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Greene D, Shiferaw Y. Identifying Key Binding Interactions Between the Cardiac L-Type Calcium Channel and Calmodulin Using Molecular Dynamics Simulations. J Phys Chem B 2024. [PMID: 38870543 DOI: 10.1021/acs.jpcb.4c02251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
Defects in the binding of the calcium sensing protein calmodulin (CaM) to the L-type calcium channel (CaV1.2) or to the ryanodine receptor type 2 (RyR2) can lead to dangerous cardiac arrhythmias with distinct phenotypes, such as long-QT syndrome (LQTS) and catecholaminergic ventricular tachycardia (CPVT). Certain CaM mutations lead to LQTS while other mutations lead to CPVT, but the mechanisms by which a specific mutation can lead to each disease phenotype are not well-understood. In this study, we use long, 2 μs molecular dynamics simulations and a multitrajectory approach to identify the key binding interactions between the IQ domain of CaV1.2 and CaM. Five key interactions are found between CaV1.2 and CaM in the C-lobe, 1 in the central linker, and 2 in the N-lobe. In addition, while 5 key interactions appear between residues 120-149 in the C-lobe of CaM when it interacts with CaV1.2, only 1 key interaction is found within this region of CaM when it interacts with the RyR2. We show that this difference in the distribution of key interactions correlates with the known distribution of CaM mutations that lead to LQTS or CPVT. This correlation suggests that a disruption of key binding interactions is a plausible mechanism that can lead to these two different disease phenotypes.
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Affiliation(s)
- D'Artagnan Greene
- Department of Physics and Astronomy, California State University Northridge, 18111 Nordhoff Street, Northridge, California 91330-8268, United States of America
| | - Yohannes Shiferaw
- Department of Physics and Astronomy, California State University Northridge, 18111 Nordhoff Street, Northridge, California 91330-8268, United States of America
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2
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Iacobucci GJ, Popescu GK. Calcium- and calmodulin-dependent inhibition of NMDA receptor currents. Biophys J 2024; 123:277-293. [PMID: 38140727 PMCID: PMC10870176 DOI: 10.1016/j.bpj.2023.12.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/05/2023] [Accepted: 12/19/2023] [Indexed: 12/24/2023] Open
Abstract
Calcium ions (Ca2+) reduce NMDA receptor currents through several distinct mechanisms. Among these, calmodulin (CaM)-dependent inhibition (CDI) accomplishes rapid, reversible, and incomplete reduction of the NMDA receptor currents in response to elevations in intracellular Ca2+. Quantitative and mechanistic descriptions of CDI of NMDA receptor-mediated signals have been marred by variability originating, in part, from differences in the conditions and metrics used to evaluate this process across laboratories. Recent ratiometric approaches to measure the magnitude and kinetics of NMDA receptor CDI have facilitated rapid insights into this phenomenon. Notably, the kinetics and magnitude of NMDA receptor CDI depend on the degree of saturation of its CaM binding sites, which represent the bona fide calcium sensor for this type of inhibition, the kinetics and magnitude of the Ca2+ signal, which depends on the biophysical properties of the NMDA receptor or of adjacent Ca2+ sources, and on the relative distribution of Ca2+ sources and CaM molecules. Given that all these factors vary widely during development, across cell types, and with physiological and pathological states, it is important to understand how NMDA receptor CDI develops and how it contributes to signaling in the central nervous system. Here, we review briefly these recent advances and highlight remaining questions about the structural and kinetic mechanisms of NMDA receptor CDI. Given that pathologies can arise from several sources, including mutations in the NMDA receptor and in CaM, understanding how CaM responds to intracellular Ca2+ signals to initiate conformational changes in NMDA receptors, and mapping the structural domains responsible will help to envision novel therapeutic strategies to neuropsychiatric diseases, which presently have limited available treatments.
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Affiliation(s)
- Gary J Iacobucci
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, SUNY, Buffalo, New York
| | - Gabriela K Popescu
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, SUNY, Buffalo, New York.
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3
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del Rivero Morfin PJ, Kochiss AL, Liedl KR, Flucher BE, Fernández-Quintero ML, Ben-Johny M. Asymmetric contribution of a selectivity filter gate in triggering inactivation of CaV1.3 channels. J Gen Physiol 2024; 156:e202313365. [PMID: 38175169 PMCID: PMC10771039 DOI: 10.1085/jgp.202313365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 10/08/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
Voltage-dependent and Ca2+-dependent inactivation (VDI and CDI, respectively) of CaV channels are two biologically consequential feedback mechanisms that fine-tune Ca2+ entry into neurons and cardiomyocytes. Although known to be initiated by distinct molecular events, how these processes obstruct conduction through the channel pore remains poorly defined. Here, focusing on ultrahighly conserved tryptophan residues in the interdomain interfaces near the selectivity filter of CaV1.3, we demonstrate a critical role for asymmetric conformational changes in mediating VDI and CDI. Specifically, mutagenesis of the domain III-IV interface, but not others, enhanced VDI. Molecular dynamics simulations demonstrate that mutations in distinct selectivity filter interfaces differentially impact conformational flexibility. Furthermore, mutations in distinct domains preferentially disrupt CDI mediated by the N- versus C-lobes of CaM, thus uncovering a scheme of structural bifurcation of CaM signaling. These findings highlight the fundamental importance of the asymmetric arrangement of the pseudotetrameric CaV pore domain for feedback inhibition.
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Affiliation(s)
| | - Audrey L. Kochiss
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E. Flucher
- Department of Physiology and Medical Physics, Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | | | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
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4
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Abstract
Calcium ions (Ca2+) are the basis of a unique and potent array of cellular responses. Calmodulin (CaM) is a small but vital protein that is able to rapidly transmit information about changes in Ca2+ concentrations to its regulatory targets. CaM plays a critical role in cellular Ca2+ signaling, and interacts with a myriad of target proteins. Ca2+-dependent modulation by CaM is a major component of a diverse array of processes, ranging from gene expression in neurons to the shaping of the cardiac action potential in heart cells. Furthermore, the protein sequence of CaM is highly evolutionarily conserved, and identical CaM proteins are encoded by three independent genes (CALM1-3) in humans. Mutations within any of these three genes may lead to severe cardiac deficits including severe long QT syndrome (LQTS) and/or catecholaminergic polymorphic ventricular tachycardia (CPVT). Research into disease-associated CaM variants has identified several proteins modulated by CaM that are likely to underlie the pathogenesis of these calmodulinopathies, including the cardiac L-type Ca2+ channel (LTCC) CaV1.2, and the sarcoplasmic reticulum Ca2+ release channel, ryanodine receptor 2 (RyR2). Here, we review the research that has been done to identify calmodulinopathic CaM mutations and evaluate the mechanisms underlying their role in disease.
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Affiliation(s)
- John W. Hussey
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Worawan B. Limpitikul
- Department of Medicine, Division of Cardiology, Massachusetts General Hospital, Boston, MA, USA
| | - Ivy E. Dick
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- CONTACT Ivy E. Dick School of Medicine, University of Maryland, Baltimore, MD21210
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5
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Wong LC, Roses-Noguer F, Bueno A, Villabriga BB, Homfray T, Till J. Early-onset cardiac arrest, prolonged QT interval, and left ventricular hypertrophy: Phenotypic manifestations of a pathogenic de novo calmodulin variant. HeartRhythm Case Rep 2023; 9:858-862. [PMID: 38204837 PMCID: PMC10774527 DOI: 10.1016/j.hrcr.2023.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024] Open
Affiliation(s)
- Leonie C.H. Wong
- Department of Paediatric Cardiology, Royal Brompton Hospital, London, United Kingdom
| | - Ferran Roses-Noguer
- Department of Paediatric Cardiology, Royal Brompton Hospital, London, United Kingdom
- Department of Paediatric Cardiology, Vall d’Hebron University Hospital, Barcelona, Spain
- European Reference Network for rare, low-prevalence, or complex diseases of the Heart (ERN GUARD-Heart)
| | - Andrea Bueno
- Department of Paediatric Cardiology, Vall d’Hebron University Hospital, Barcelona, Spain
| | - Begoña Benito Villabriga
- Department of Cardiology, Vall d’Hebron University Hospital, Barcelona, Spain
- European Reference Network for rare, low-prevalence, or complex diseases of the Heart (ERN GUARD-Heart)
| | - Tessa Homfray
- Department of Medical Genetics, Royal Brompton Hospital, London, United Kingdom
- Department of Medical Genetics, St George’s University of London, London, United Kingdom
| | - Jan Till
- Department of Paediatric Cardiology, Royal Brompton Hospital, London, United Kingdom
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6
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Kang PW, Woodbury L, Angsutararux P, Sambare N, Shi J, Marras M, Abella C, Bedi A, Zinn D, Cui J, Silva JR. Arrhythmia-associated calmodulin variants interact with KCNQ1 to confer aberrant membrane trafficking and function. PNAS NEXUS 2023; 2:pgad335. [PMID: 37965565 PMCID: PMC10642763 DOI: 10.1093/pnasnexus/pgad335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 10/04/2023] [Indexed: 11/16/2023]
Abstract
Missense variants in calmodulin (CaM) predispose patients to arrhythmias associated with high mortality rates ("calmodulinopathy"). As CaM regulates many key cardiac ion channels, an understanding of disease mechanism associated with CaM variant arrhythmias requires elucidating individual CaM variant effects on distinct channels. One key CaM regulatory target is the KCNQ1 (KV7.1) voltage-gated potassium channel that carries the IKs current. Yet, relatively little is known as to how CaM variants interact with KCNQ1 or affect its function. Here, we take a multipronged approach employing a live-cell fluorescence resonance energy transfer binding assay, fluorescence trafficking assay, and functional electrophysiology to characterize >10 arrhythmia-associated CaM variants for effect on KCNQ1 CaM binding, membrane trafficking, and channel function. We identify one variant (G114W) that exhibits severely weakened binding to KCNQ1 but find that most other CaM variants interact with similar binding affinity to KCNQ1 when compared with CaM wild-type over physiological Ca2+ ranges. We further identify several CaM variants that affect KCNQ1 and IKs membrane trafficking and/or baseline current activation kinetics, thereby delineating KCNQ1 dysfunction in calmodulinopathy. Lastly, we identify CaM variants with no effect on KCNQ1 function. This study provides extensive functional data that reveal how CaM variants contribute to creating a proarrhythmic substrate by causing abnormal KCNQ1 membrane trafficking and current conduction. We find that CaM variant regulation of KCNQ1 is not uniform with effects varying from benign to significant loss of function, suggesting how CaM variants predispose patients to arrhythmia via the dysregulation of multiple cardiac ion channels. Classification: Biological, Health, and Medical Sciences, Physiology.
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Affiliation(s)
- Po wei Kang
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Lucy Woodbury
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Paweorn Angsutararux
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Namit Sambare
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jingyi Shi
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Martina Marras
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Carlota Abella
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Anish Bedi
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - DeShawn Zinn
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
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Thanassoulas A, Theodoridou M, Barrak L, Riguene E, Alyaarabi T, Elrayess MA, Lai FA, Nomikos M. Arrhythmia-Associated Calmodulin E105A Mutation Alters the Binding Affinity of CaM to a Ryanodine Receptor 2 CaM-Binding Pocket. Int J Mol Sci 2023; 24:15630. [PMID: 37958614 PMCID: PMC10649572 DOI: 10.3390/ijms242115630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 10/21/2023] [Accepted: 10/24/2023] [Indexed: 11/15/2023] Open
Abstract
Calmodulin (CaM) is a small, multifunctional calcium (Ca2+)-binding sensor that binds and regulates the open probability of cardiac ryanodine receptor 2 (RyR2) at both low and high cytosolic Ca2+ concentrations. Recent isothermal titration calorimetry (ITC) studies of a number of peptides that correspond to different regions of human RyR2 showed that two regions of human RyR2 (3584-3602aa and 4255-4271aa) bind with high affinity to CaM, suggesting that these two regions might contribute to a putative RyR2 intra-subunit CaM-binding pocket. Moreover, a previously characterized de novo long QT syndrome (LQTS)-associated missense CaM mutation (E105A) which was identified in a 6-year-old boy, who experienced an aborted first episode of cardiac arrest revealed that this mutation dysregulates normal cardiac function in zebrafish by a complex mechanism that involves alterations in both CaM-Ca2+ and CaM-RyR2 interactions. Herein, to gain further insight into how the CaM E105A mutation leads to severe cardiac arrhythmia, we generated large quantities of recombinant CaMWT and CaME105A proteins. We then performed ITC experiments to investigate and compare the interactions of CaMWT and CaME105A mutant protein with two synthetic peptides that correspond to the two aforementioned human RyR2 regions, which we have proposed to contribute to the RyR2 CaM-binding pocket. Our data reveal that the E105A mutation has a significant negative effect on the interaction of CaM with both RyR2 regions in the presence and absence of Ca2+, highlighting the potential contribution of these two human RyR2 regions to an RyR2 CaM-binding pocket, which may be essential for physiological CaM/RyR2 association and thus channel regulation.
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Affiliation(s)
- Angelos Thanassoulas
- College of Medicine, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.T.); (L.B.); (E.R.); (T.A.); (M.A.E.); (F.A.L.)
| | - Maria Theodoridou
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar;
| | - Laila Barrak
- College of Medicine, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.T.); (L.B.); (E.R.); (T.A.); (M.A.E.); (F.A.L.)
| | - Emna Riguene
- College of Medicine, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.T.); (L.B.); (E.R.); (T.A.); (M.A.E.); (F.A.L.)
| | - Tamader Alyaarabi
- College of Medicine, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.T.); (L.B.); (E.R.); (T.A.); (M.A.E.); (F.A.L.)
| | - Mohamed A. Elrayess
- College of Medicine, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.T.); (L.B.); (E.R.); (T.A.); (M.A.E.); (F.A.L.)
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar;
| | - F. Anthony Lai
- College of Medicine, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.T.); (L.B.); (E.R.); (T.A.); (M.A.E.); (F.A.L.)
| | - Michail Nomikos
- College of Medicine, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.T.); (L.B.); (E.R.); (T.A.); (M.A.E.); (F.A.L.)
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8
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del Rivero Morfin PJ, Kochiss AL, Liedl KR, Flucher BE, Fernández-Quintero ML, Ben-Johny M. Asymmetric Contribution of a Selectivity Filter Gate in Triggering Inactivation of Ca V1.3 Channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.21.558864. [PMID: 37790368 PMCID: PMC10542529 DOI: 10.1101/2023.09.21.558864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Voltage-dependent and Ca2+-dependent inactivation (VDI and CDI, respectively) of CaV channels are two biologically consequential feedback mechanisms that fine-tune Ca2+ entry into neurons and cardiomyocytes. Although known to be initiated by distinct molecular events, how these processes obstruct conduction through the channel pore remains poorly defined. Here, focusing on ultra-highly conserved tryptophan residues in the inter-domain interfaces near the selectivity filter of CaV1.3, we demonstrate a critical role for asymmetric conformational changes in mediating VDI and CDI. Specifically, mutagenesis of the domain III-IV interface, but not others, enhanced VDI. Molecular dynamics simulations demonstrate that mutations in distinct selectivity filter interfaces differentially impact conformational flexibility. Furthermore, mutations in distinct domains preferentially disrupt CDI mediated by the N- versus C-lobes of CaM, thus uncovering a scheme of structural bifurcation of CaM signaling. These findings highlight the fundamental importance of the asymmetric arrangement of the pseudo-tetrameric CaV pore domain for feedback inhibition.
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Affiliation(s)
| | - Audrey L. Kochiss
- Department of Physiology and Cellular Biophysics, Columbia University
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E. Flucher
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | | | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University
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9
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Crotti L, Spazzolini C, Nyegaard M, Overgaard MT, Kotta MC, Dagradi F, Sala L, Aiba T, Ayers MD, Baban A, Barc J, Beach CM, Behr ER, Bos JM, Cerrone M, Covi P, Cuneo B, Denjoy I, Donner B, Elbert A, Eliasson H, Etheridge SP, Fukuyama M, Girolami F, Hamilton R, Horie M, Iascone M, Jaimez JJ, Jensen HK, Kannankeril PJ, Kaski JP, Makita N, Muñoz-Esparza C, Odland HH, Ohno S, Papagiannis J, Porretta AP, Prandstetter C, Probst V, Robyns T, Rosenthal E, Rosés-Noguer F, Sekarski N, Singh A, Spentzou G, Stute F, Tfelt-Hansen J, Till J, Tobert KE, Vinocur JM, Webster G, Wilde AAM, Wolf CM, Ackerman MJ, Schwartz PJ. Clinical presentation of calmodulin mutations: the International Calmodulinopathy Registry. Eur Heart J 2023; 44:3357-3370. [PMID: 37528649 PMCID: PMC10499544 DOI: 10.1093/eurheartj/ehad418] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/14/2023] [Accepted: 06/13/2023] [Indexed: 08/03/2023] Open
Abstract
AIMS Calmodulinopathy due to mutations in any of the three CALM genes (CALM1-3) causes life-threatening arrhythmia syndromes, especially in young individuals. The International Calmodulinopathy Registry (ICalmR) aims to define and link the increasing complexity of the clinical presentation to the underlying molecular mechanisms. METHODS AND RESULTS The ICalmR is an international, collaborative, observational study, assembling and analysing clinical and genetic data on CALM-positive patients. The ICalmR has enrolled 140 subjects (median age 10.8 years [interquartile range 5-19]), 97 index cases and 43 family members. CALM-LQTS and CALM-CPVT are the prevalent phenotypes. Primary neurological manifestations, unrelated to post-anoxic sequelae, manifested in 20 patients. Calmodulinopathy remains associated with a high arrhythmic event rate (symptomatic patients, n = 103, 74%). However, compared with the original 2019 cohort, there was a reduced frequency and severity of all cardiac events (61% vs. 85%; P = .001) and sudden death (9% vs. 27%; P = .008). Data on therapy do not allow definitive recommendations. Cardiac structural abnormalities, either cardiomyopathy or congenital heart defects, are present in 30% of patients, mainly CALM-LQTS, and lethal cases of heart failure have occurred. The number of familial cases and of families with strikingly different phenotypes is increasing. CONCLUSION Calmodulinopathy has pleiotropic presentations, from channelopathy to syndromic forms. Clinical severity ranges from the early onset of life-threatening arrhythmias to the absence of symptoms, and the percentage of milder and familial forms is increasing. There are no hard data to guide therapy, and current management includes pharmacological and surgical antiadrenergic interventions with sodium channel blockers often accompanied by an implantable cardioverter-defibrillator.
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Affiliation(s)
- Lia Crotti
- Istituto Auxologico Italiano IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Via Pier Lombardo 22, 20135 Milan, Italy
- Department of Medicine and Surgery, University of Milano-Bicocca, Piazza dell'Ateneo Nuovo, 1, 20126 Milan, Italy
| | - Carla Spazzolini
- Istituto Auxologico Italiano IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Via Pier Lombardo 22, 20135 Milan, Italy
| | - Mette Nyegaard
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Michael T Overgaard
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Maria-Christina Kotta
- Istituto Auxologico Italiano IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Via Pier Lombardo 22, 20135 Milan, Italy
| | - Federica Dagradi
- Istituto Auxologico Italiano IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Via Pier Lombardo 22, 20135 Milan, Italy
| | - Luca Sala
- Istituto Auxologico Italiano IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Via Pier Lombardo 22, 20135 Milan, Italy
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Takeshi Aiba
- Division of Arrhythmia, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Mark D Ayers
- Department of Pediatrics, Division of Pediatric Cardiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anwar Baban
- Member of the European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
- Pediatric Cardiology and Arrhythmia/Syncope Units, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Julien Barc
- Université de Nantes, CHU Nantes, CNRS, INSERM, L’institut du Thorax, Nantes, France
| | - Cheyenne M Beach
- Pediatric Cardiology, Yale School of Medicine, New Haven, CT, USA
| | - Elijah R Behr
- Cardiology Section, Institute of Molecular and Clinical Sciences, St George’s University of London and Cardiovascular Clinical Academic Group, St George’s University Hospitals NHS Foundation Trust, UK
| | - J Martijn Bos
- Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental Therapeutics, Division of Heart Rhythm Services and Pediatric Cardiology, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Marina Cerrone
- Inherited Arrhythmias Clinic, Leon H. Charney Division of Cardiology, NYU Grossmann School of Medicine, New York, NY, USA
| | - Peter Covi
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Bettina Cuneo
- Department of Pediatrics, Section of Cardiology, University of Denver School of Medicine, Aurora, CO, USA
| | - Isabelle Denjoy
- Centre de Référence Maladies Cardiaques Héréditaires Filière Cardiogen, Département de Rythmologie, Groupe Hospitalier Bichat-Claude Bernard, Paris, France
| | - Birgit Donner
- Kardiologie, Universitäts-Kinderspital beider Basel (UKBB), Basel, Switzerland
| | - Adrienne Elbert
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Håkan Eliasson
- Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden
- Pediatric Cardiology C8:34, Karolinska University Hospital, Stockholm, Sweden
| | - Susan P Etheridge
- Department of Pediatrics, Division of Pediatric Cardiology, University of Utah and Primary Children’s Hospital, Salt Lake City, UT, USA
| | - Megumi Fukuyama
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Shiga, Japan
| | | | - Robert Hamilton
- Division of Cardiology, The Hospital for Sick Children (SickKids), Toronto, ON, Canada
| | - Minoru Horie
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Shiga, Japan
| | - Maria Iascone
- Laboratorio di Genetica Medica, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Juan Jiménez Jaimez
- Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitario IBS Granada, Spain
| | - Henrik Kjærulf Jensen
- Department of Cardiology, Department of Clinical Medicine, Aarhus University Hospital, Aarhus University, K-8200 Aarhus N, Denmark
| | - Prince J Kannankeril
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Juan P Kaski
- Centre for Paediatric Inherited and Rare Cardiovascular Disease, Institute of Cardiovascular Science, University College London, Zayed Centre for Research into Rare Disease in Childhood, London, UK
- Centre for Inherited Cardiovascular Diseases, Great Ormond Street Hospital, London, UK
| | - Naomasa Makita
- National Cerebral and Cardiovascular Center, Suita, Japan
- Sapporo Teishinkai Hospital, Sapporo, Japan
| | - Carmen Muñoz-Esparza
- Member of the European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
- Inherited Cardiac Disease Unit, Hospital Universitario Virgen Arrixaca, Murcia, Spain
| | - Hans H Odland
- Department of Cardiology and Pediatric Cardiology, Section for Arrhythmias, Oslo University Hospital, Oslo, Norway
| | - Seiko Ohno
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - John Papagiannis
- Pediatric and Adult Congenital Heart Disease, Onassis Cardiac Surgery Center, Athens, Greece
| | - Alessandra Pia Porretta
- Unité des Troubles du Rythme, Service de Cardiologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Christopher Prandstetter
- Medical Faculty, Johannes Kepler University Linz, Linz, Austria
- Department of Pediatric Cardiology, Kepler University Hospital, Linz, Austria
| | - Vincent Probst
- Service de Cardiologie, L’institut du Thorax, CHU Nantes, Nantes, France
| | - Tomas Robyns
- Member of the European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
- Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium
| | - Eric Rosenthal
- Evelina London Children’s Hospital, St Thomas’ Hospital, London, UK
| | - Ferran Rosés-Noguer
- Member of the European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
- Lead Paediatric Cardiology Department, Vall d’Hebron University Hospital, Barcelona, Spain
- Royal Brompton Hospital NHS Guy’s and St Thomas Foundation Trust, London, UK
| | - Nicole Sekarski
- Unité de Cardiologie Pédiatrique, Département Médico-Chirurgical de Pédiatrie, CHUV | Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Anoop Singh
- Department of Pediatrics, Medical College of Wisconsin, Wauwatosa, WI, USA
| | | | - Fridrike Stute
- Department of Pediatric Cardiology, University Heart & Vascular Center Hamburg, Hamburg, Germany
| | - Jacob Tfelt-Hansen
- Member of the European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
- Section of Genetics, Department of Forensic Medicine, Faculty of Medical Sciences, University of Copenhagen, Denmark
- Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jan Till
- Royal Brompton Hospital NHS Guy’s and St Thomas Foundation Trust, London, UK
| | - Kathryn E Tobert
- Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental Therapeutics, Division of Heart Rhythm Services and Pediatric Cardiology, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | | | - Gregory Webster
- Ann & Robert H. Lurie Children’s Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Arthur A M Wilde
- Member of the European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart: ERN GUARD-Heart
- Department of Cardiology, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, The Netherlands
| | - Cordula M Wolf
- Center for Rare Congenital Heart Diseases, Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, Technical University Munich, School of Medicine & Health, Munich, Germany
| | - Michael J Ackerman
- Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental Therapeutics, Division of Heart Rhythm Services and Pediatric Cardiology, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Peter J Schwartz
- Istituto Auxologico Italiano IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Via Pier Lombardo 22, 20135 Milan, Italy
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10
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Wren LM, DeKeyser JM, Barefield DY, Hawkins NA, McNally EM, Kearney JA, Wasserstrom JA, George AL. Sex and Gene Influence Arrhythmia Susceptibility in Murine Models of Calmodulinopathy. Circ Arrhythm Electrophysiol 2023; 16:e010891. [PMID: 37589122 PMCID: PMC10530303 DOI: 10.1161/circep.122.010891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 07/16/2023] [Indexed: 08/18/2023]
Abstract
BACKGROUND Pathogenic variants in genes encoding CaM (calmodulin) are associated with a life-threatening ventricular arrhythmia syndrome (calmodulinopathy). The in vivo consequences of CaM variants have not been studied extensively and there is incomplete understanding of the genotype-phenotype relationship for recurrent variants. We investigated effects of different factors on calmodulinopathy phenotypes using 2 mouse models with a recurrent pathogenic variant (N98S) in Calm1 or Calm2. METHODS Genetically engineered mice with heterozygous N98S pathogenic variants in Calm1 or Calm2 were generated. Differences between the sexes and affected genes were assessed using multiple physiological assays at the cellular and whole animal levels. Statistical significance among groups was evaluated using 1-way ANOVA or the Kruskal-Wallis test when data were not normally distributed. RESULTS Calm1N98S/+ (Calm1S/+) or Calm2N98S/+ (Calm2S/+) mice exhibited sinus bradycardia and were more susceptible to arrhythmias after exposure to epinephrine and caffeine. Male Calm1S/+ mice had the most severe arrhythmia phenotype with evidence of early embryonic lethality, greater susceptibility for arrhythmic events, frequent premature beats, corrected QT prolongation, and more heart rate variability after epinephrine and caffeine than females with the same genotype. Calm2 S/+ mice exhibited a less severe phenotype, with female Calm2 S/+ mice having the least severe arrhythmia susceptibility. Flecainide was not effective in preventing arrhythmias in heterozygous CaM-N98S mice. Intracellular Ca2+ transients observed in isolated ventricular cardiomyocytes from male heterozygous CaM-N98S mice had lower peak amplitudes and slower sarcoplasmic reticulum Ca2+ release following in vitro exposure to epinephrine and caffeine, which were not observed in cardiomyocytes from heterozygous female CaM-N98S mice. CONCLUSIONS We report heterogeneity in arrhythmia susceptibility and cardiomyocyte Ca2+ dynamics among male and female mice heterozygous for a recurrent pathogenic variant in Calm1 or Calm2, illustrating a complex calmodulinopathy phenotype in vivo. Further investigation of sex and genetic differences may help identify the molecular basis for this heterogeneity.
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Affiliation(s)
- Lisa M Wren
- Department of Pharmacology (L.M.W., J.-M.D., N.A.H., J.A.K., A.L.G.), The Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Jean-Marc DeKeyser
- Department of Pharmacology (L.M.W., J.-M.D., N.A.H., J.A.K., A.L.G.), The Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - David Y Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL (D.Y.B.)
| | - Nicole A Hawkins
- Department of Pharmacology (L.M.W., J.-M.D., N.A.H., J.A.K., A.L.G.), The Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Elizabeth M McNally
- Center for Genetic Medicine (E.M.M.), The Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Jennifer A Kearney
- Department of Pharmacology (L.M.W., J.-M.D., N.A.H., J.A.K., A.L.G.), The Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - J Andrew Wasserstrom
- Department of Medicine (J.A.W.), The Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Alfred L George
- Department of Pharmacology (L.M.W., J.-M.D., N.A.H., J.A.K., A.L.G.), The Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL
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11
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McCormick L, Wadmore K, Milburn A, Gupta N, Morris R, Held M, Prakash O, Carr J, Barrett‐Jolley R, Dart C, Helassa N. Long QT syndrome-associated calmodulin variants disrupt the activity of the slowly activating delayed rectifier potassium channel. J Physiol 2023; 601:3739-3764. [PMID: 37428651 PMCID: PMC10952621 DOI: 10.1113/jp284994] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/21/2023] [Indexed: 07/12/2023] Open
Abstract
Calmodulin (CaM) is a highly conserved mediator of calcium (Ca2+ )-dependent signalling and modulates various cardiac ion channels. Genotyping has revealed several CaM mutations associated with long QT syndrome (LQTS). LQTS patients display prolonged ventricular recovery times (QT interval), increasing their risk of incurring life-threatening arrhythmic events. Loss-of-function mutations to Kv7.1 (which drives the slow delayed rectifier potassium current, IKs, a key ventricular repolarising current) are the largest contributor to congenital LQTS (>50% of cases). CaM modulates Kv7.1 to produce a Ca2+ -sensitive IKs, but little is known about the consequences of LQTS-associated CaM mutations on Kv7.1 function. Here, we present novel data characterising the biophysical and modulatory properties of three LQTS-associated CaM variants (D95V, N97I and D131H). We showed that mutations induced structural alterations in CaM and reduced affinity for Kv7.1, when compared with wild-type (WT). Using HEK293T cells expressing Kv7.1 channel subunits (KCNQ1/KCNE1) and patch-clamp electrophysiology, we demonstrated that LQTS-associated CaM variants reduced current density at systolic Ca2+ concentrations (1 μm), revealing a direct QT-prolonging modulatory effect. Our data highlight for the first time that LQTS-associated perturbations to CaM's structure impede complex formation with Kv7.1 and subsequently result in reduced IKs. This provides a novel mechanistic insight into how the perturbed structure-function relationship of CaM variants contributes to the LQTS phenotype. KEY POINTS: Calmodulin (CaM) is a ubiquitous, highly conserved calcium (Ca2+ ) sensor playing a key role in cardiac muscle contraction. Genotyping has revealed several CaM mutations associated with long QT syndrome (LQTS), a life-threatening cardiac arrhythmia syndrome. LQTS-associated CaM variants (D95V, N97I and D131H) induced structural alterations, altered binding to Kv7.1 and reduced IKs. Our data provide a novel mechanistic insight into how the perturbed structure-function relationship of CaM variants contributes to the LQTS phenotype.
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Affiliation(s)
- Liam McCormick
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
- Manchester Centre for Genomic Medicine, North West Genomic Laboratory HubSaint Mary's HospitalManchesterUK
| | - Kirsty Wadmore
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Amy Milburn
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Nitika Gupta
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Rachael Morris
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Marie Held
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Ohm Prakash
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Joseph Carr
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Richard Barrett‐Jolley
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Caroline Dart
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Nordine Helassa
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
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12
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Brohus M, Busuioc AO, Wimmer R, Nyegaard M, Overgaard MT. Calmodulin mutations affecting Gly114 impair binding to the Na V1.5 IQ-domain. Front Pharmacol 2023; 14:1210140. [PMID: 37663247 PMCID: PMC10469309 DOI: 10.3389/fphar.2023.1210140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/25/2023] [Indexed: 09/05/2023] Open
Abstract
Missense variants in CALM genes encoding the Ca2+-binding protein calmodulin (CaM) cause severe cardiac arrhythmias. The disease mechanisms have been attributed to dysregulation of RyR2, for Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) and/or CaV1.2, for Long-QT Syndrome (LQTS). Recently, a novel CALM2 variant, G114R, was identified in a mother and two of her four children, all of whom died suddenly while asleep at a young age. The G114R variant impairs closure of CaV1.2 and RyR2, consistent with a CPVT and/or mild LQTS phenotype. However, the children carrying the CALM2 G114R variant displayed a phenotype commonly observed with variants in NaV1.5, i.e., Brugada Syndrome (BrS) or LQT3, where death while asleep is a common feature. We therefore hypothesized that the G114R variant specifically would interfere with NaV1.5 binding. Here, we demonstrate that CaM binding to the NaV1.5 IQ-domain is severely impaired for two CaM variants G114R and G114W. The impact was most severe at low and intermediate Ca2+ concentrations (up to 4 µM) resulting in more than a 50-fold reduction in NaV1.5 binding affinity, and a smaller 1.5 to 11-fold reduction at high Ca2+ concentrations (25-400 µM). In contrast, the arrhythmogenic CaM-N98S variant only induced a 1.5-fold reduction in NaV1.5 binding and only at 4 µM Ca2+. A non-arrhythmogenic I10T variant in CaM did not impair NaV1.5 IQ binding. These data suggest that the interaction between NaV1.5 and CaM is decreased with certain CaM variants, which may alter the cardiac sodium current, INa. Overall, these results suggest that the phenotypic spectrum of calmodulinopathies may likely expand to include BrS- and/or LQT3-like traits.
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Affiliation(s)
- Malene Brohus
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Ana-Octavia Busuioc
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Reinhard Wimmer
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Mette Nyegaard
- Department of Health Science and Technology, Aalborg University, Gistrup, Denmark
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13
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Williams RB, Alam Afsar MN, Tikunova S, Kou Y, Fang X, Somarathne RP, Gyawu RF, Knotts GM, Agee TA, Garcia SA, Losordo LD, Fitzkee NC, Kekenes-Huskey PM, Davis JP, Johnson CN. Human disease-associated calmodulin mutations alter calcineurin function through multiple mechanisms. Cell Calcium 2023; 113:102752. [PMID: 37245392 PMCID: PMC10330910 DOI: 10.1016/j.ceca.2023.102752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 04/29/2023] [Accepted: 05/03/2023] [Indexed: 05/30/2023]
Abstract
Calmodulin (CaM) is a ubiquitous, calcium-sensing protein that regulates a multitude of processes throughout the body. In response to changes in [Ca2+], CaM modifies, activates, and deactivates enzymes and ion channels, as well as many other cellular processes. The importance of CaM is highlighted by the conservation of an identical amino acid sequence in all mammals. Alterations to CaM amino acid sequence were once thought to be incompatible with life. During the last decade modifications to the CaM protein sequence have been observed in patients suffering from life-threatening heart disease (calmodulinopathy). Thus far, inadequate or untimely interaction between mutant CaM and several proteins (LTCC, RyR2, and CaMKII) have been identified as mechanisms underlying calmodulinopathy. Given the extensive number of CaM interactions in the body, there are likely many consequences for altering CaM protein sequence. Here, we demonstrate that disease-associated CaM mutations alter the sensitivity and activity of the Ca2+-CaM-enhanced serine/threonine phosphatase calcineurin (CaN). Biophysical characterization by circular dichroism, solution NMR spectroscopy, stopped-flow kinetic measurements, and MD simulations provide mechanistic insight into mutation dysfunction as well as highlight important aspects of CaM Ca2+ signal transduction. We find that individual CaM point mutations (N53I, F89L, D129G, and F141L) impair CaN function, however, the mechanisms are not the same. Specifically, individual point mutations can influence or modify the following properties: CaM binding, Ca2+ binding, and/or Ca2+kinetics. Moreover, structural aspects of the CaNCaM complex can be altered in manners that indicate changes to allosteric transmission of CaM binding to the enzyme active site. Given that loss of CaN function can be fatal, as well as evidence that CaN modifies ion channels already associated with calmodulinopathy, our results raise the possibility that altered CaN function contributes to calmodulinopathy.
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Affiliation(s)
- Ryan B Williams
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Md Nure Alam Afsar
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Svetlana Tikunova
- Department of Physiology and Cell Biology, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus OH 43210, U.S.A
| | - Yongjun Kou
- Department of Physiology and Cell Biology, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus OH 43210, U.S.A
| | - Xuan Fang
- Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood Illinois 60153, U.S.A
| | - Radha P Somarathne
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Rita F Gyawu
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Garrett M Knotts
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Taylor A Agee
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Sara A Garcia
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Luke D Losordo
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Nicholas C Fitzkee
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A
| | - Peter M Kekenes-Huskey
- Department of Cell and Molecular Physiology, Loyola University of Chicago, Maywood Illinois 60153, U.S.A
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus OH 43210, U.S.A.
| | - Christopher N Johnson
- Department of Chemistry, Mississippi State University, Starkville MS 39759, U.S.A; Vanderbilt Center for Arrhythmia Research and Therapeutics, Nashville TN 37232, U.S.A.
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14
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Gao J, Makiyama T, Yamamoto Y, Kobayashi T, Aoki H, Maurissen TL, Wuriyanghai Y, Kashiwa A, Imamura T, Aizawa T, Huang H, Kohjitani H, Nishikawa M, Chonabayashi K, Fukuyama M, Manabe H, Nakau K, Wada T, Kato K, Toyoda F, Yoshida Y, Makita N, Woltjen K, Ohno S, Kurebayashi N, Murayama T, Sakurai T, Horie M, Kimura T. Novel Calmodulin Variant p.E46K Associated With Severe Catecholaminergic Polymorphic Ventricular Tachycardia Produces Robust Arrhythmogenicity in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Circ Arrhythm Electrophysiol 2023; 16:e011387. [PMID: 36866681 DOI: 10.1161/circep.122.011387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
BACKGROUND CaM (calmodulin) is a ubiquitously expressed, multifunctional Ca2+ sensor protein that regulates numerous proteins. Recently, CaM missense variants have been identified in patients with malignant inherited arrhythmias, such as long QT syndrome and catecholaminergic polymorphic ventricular tachycardia (CPVT). However, the exact mechanism of CaM-related CPVT in human cardiomyocytes remains unclear. In this study, we sought to investigate the arrhythmogenic mechanism of CPVT caused by a novel variant using human induced pluripotent stem cell (iPSC) models and biochemical assays. METHODS We generated iPSCs from a patient with CPVT bearing CALM2 p.E46K. As comparisons, we used 2 control lines including an isogenic line, and another iPSC line from a patient with long QT syndrome bearing CALM2 p.N98S (also reported in CPVT). Electrophysiological properties were investigated using iPSC-cardiomyocytes. We further examined the RyR2 (ryanodine receptor 2) and Ca2+ affinities of CaM using recombinant proteins. RESULTS We identified a novel de novo heterozygous variant, CALM2 p.E46K, in 2 unrelated patients with CPVT accompanied by neurodevelopmental disorders. The E46K-cardiomyocytes exhibited more frequent abnormal electrical excitations and Ca2+ waves than the other lines in association with increased Ca2+ leakage from the sarcoplasmic reticulum via RyR2. Furthermore, the [3H]ryanodine binding assay revealed that E46K-CaM facilitated RyR2 function especially by activating at low [Ca2+] levels. The real-time CaM-RyR2 binding analysis demonstrated that E46K-CaM had a 10-fold increased RyR2 binding affinity compared with wild-type CaM which may account for the dominant effect of the mutant CaM. Additionally, the E46K-CaM did not affect CaM-Ca2+ binding or L-type calcium channel function. Finally, antiarrhythmic agents, nadolol and flecainide, suppressed abnormal Ca2+ waves in E46K-cardiomyocytes. CONCLUSIONS We, for the first time, established a CaM-related CPVT iPSC-CM model which recapitulated severe arrhythmogenic features resulting from E46K-CaM dominantly binding and facilitating RyR2. In addition, the findings in iPSC-based drug testing will contribute to precision medicine.
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Affiliation(s)
- Jingshan Gao
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takeru Makiyama
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Community Medicine Supporting System (T. Makiyama), Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yuta Yamamoto
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Bioscience & Genetics (Y. Yamamoto, S.O.), National Cerebral & Cardiovascular Center, Suita, Japan
- Now with Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA (Y. Yamamoto)
| | - Takuya Kobayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan (T. Kobayashi, N.K., T. Murayama, T.S.)
| | - Hisaaki Aoki
- Department of Pediatric Cardiology, Osaka Women's & Children's Hospital, Osaka, Japan (H.A.)
| | - Thomas L Maurissen
- Department of Life Science Frontiers (T.L.M., K.W.), Center for iPS Cell Research & Application (CiRA), Kyoto University, Kyoto, Japan
- Now with Roche Pharma Research & Early Development, Immunology, Infectious Diseases & Ophthalmology, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland (T.L.M.)
| | - Yimin Wuriyanghai
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
- Now with Department of Internal medicine, Peking University Third Hospital, Beijing, China (Y.W.)
| | - Asami Kashiwa
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tomohiko Imamura
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takanori Aizawa
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hai Huang
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hirohiko Kohjitani
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Misato Nishikawa
- Department of Cell Growth & Differentiation (M.N., K.C., Y. Yoshida), Center for iPS Cell Research & Application (CiRA), Kyoto University, Kyoto, Japan
| | - Kazuhisa Chonabayashi
- Department of Hematology & Oncology (K.C.), Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Cell Growth & Differentiation (M.N., K.C., Y. Yoshida), Center for iPS Cell Research & Application (CiRA), Kyoto University, Kyoto, Japan
| | - Megumi Fukuyama
- Department of Cardiovascular Medicine (M.F., K.K., M.H.), Shiga University of Medical Science, Otsu, Japan
| | - Hiromi Manabe
- Department of Pediatrics, Asahikawa Kosei General Hospital (H.M.), Asahikawa Medical University, Asahikawa, Japan
| | - Kouichi Nakau
- Asahikawa, Japan and Department of Pediatrics (K.N.), Asahikawa Medical University, Asahikawa, Japan
| | - Tsutomu Wada
- Department of Pediatrics, Sapporo Medical University Hospital, Sapporo, Japan (T.W.)
| | - Koichi Kato
- Department of Cardiovascular Medicine (M.F., K.K., M.H.), Shiga University of Medical Science, Otsu, Japan
| | - Futoshi Toyoda
- Department of Physiology (F.T.), Shiga University of Medical Science, Otsu, Japan
| | - Yoshinori Yoshida
- Department of Cell Growth & Differentiation (M.N., K.C., Y. Yoshida), Center for iPS Cell Research & Application (CiRA), Kyoto University, Kyoto, Japan
| | - Naomasa Makita
- Omics Research Center (N.M.), National Cerebral & Cardiovascular Center, Suita, Japan
- Now with Department of Cardiology, Sapporo Teishinkai Hospital, Sapporo, Japan (N.M.)
| | - Knut Woltjen
- Department of Life Science Frontiers (T.L.M., K.W.), Center for iPS Cell Research & Application (CiRA), Kyoto University, Kyoto, Japan
| | - Seiko Ohno
- Department of Bioscience & Genetics (Y. Yamamoto, S.O.), National Cerebral & Cardiovascular Center, Suita, Japan
| | - Nagomi Kurebayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan (T. Kobayashi, N.K., T. Murayama, T.S.)
| | - Takashi Murayama
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan (T. Kobayashi, N.K., T. Murayama, T.S.)
| | - Takashi Sakurai
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan (T. Kobayashi, N.K., T. Murayama, T.S.)
| | - Minoru Horie
- Department of Cardiovascular Medicine (M.F., K.K., M.H.), Shiga University of Medical Science, Otsu, Japan
| | - Takeshi Kimura
- Department of Cardiovascular Medicine (J.G., T. Makiyama, Y. Yamamoto, Y.W., A.K., T.I., T.A., H.H., H.K., T. Kimura), Kyoto University Graduate School of Medicine, Kyoto, Japan
- Now with Department of Cardiology, Hirakata Kohsai Hospital, Osaka, Japan (T. Kimura)
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15
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Kuo CWS, Dobi S, Gök C, Da Silva Costa A, Main A, Robertson-Gray O, Baptista-Hon D, Wypijewski KJ, Costello H, Hales TG, MacQuaide N, Smith GL, Fuller W. Palmitoylation of the pore-forming subunit of Ca(v)1.2 controls channel voltage sensitivity and calcium transients in cardiac myocytes. Proc Natl Acad Sci U S A 2023; 120:e2207887120. [PMID: 36745790 PMCID: PMC9963536 DOI: 10.1073/pnas.2207887120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 12/07/2022] [Indexed: 02/08/2023] Open
Abstract
Mammalian voltage-activated L-type Ca2+ channels, such as Ca(v)1.2, control transmembrane Ca2+ fluxes in numerous excitable tissues. Here, we report that the pore-forming α1C subunit of Ca(v)1.2 is reversibly palmitoylated in rat, rabbit, and human ventricular myocytes. We map the palmitoylation sites to two regions of the channel: The N terminus and the linker between domains I and II. Whole-cell voltage clamping revealed a rightward shift of the Ca(v)1.2 current-voltage relationship when α1C was not palmitoylated. To examine function, we expressed dihydropyridine-resistant α1C in human induced pluripotent stem cell-derived cardiomyocytes and measured Ca2+ transients in the presence of nifedipine to block the endogenous channels. The transients generated by unpalmitoylatable channels displayed a similar activation time course but significantly reduced amplitude compared to those generated by wild-type channels. We thus conclude that palmitoylation controls the voltage sensitivity of Ca(v)1.2. Given that the identified Ca(v)1.2 palmitoylation sites are also conserved in most Ca(v)1 isoforms, we propose that palmitoylation of the pore-forming α1C subunit provides a means to regulate the voltage sensitivity of voltage-activated Ca2+ channels in excitable cells.
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Affiliation(s)
- Chien-Wen S. Kuo
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Sara Dobi
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Caglar Gök
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Ana Da Silva Costa
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Alice Main
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Olivia Robertson-Gray
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Daniel Baptista-Hon
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
- Center for Biomedicine and Innovations, Faculty of Medicine, Macau University of Science and Technology, Macau SAR, 999078China
| | | | - Hannah Costello
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Tim G. Hales
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Niall MacQuaide
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Godfrey L. Smith
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - William Fuller
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
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16
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Kang PW, Woodbury L, Angsutararux P, Sambare N, Shi J, Marras M, Abella C, Bedi A, Zinn D, Cui J, Silva JR. Arrhythmia-associated Calmodulin Variants Interact with KCNQ1 to Confer Aberrant Membrane Trafficking and Function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.28.526031. [PMID: 36747728 PMCID: PMC9900995 DOI: 10.1101/2023.01.28.526031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Rationale Missense variants in calmodulin (CaM) predispose patients to arrhythmias associated with high mortality rates. As CaM regulates several key cardiac ion channels, a mechanistic understanding of CaM variant-associated arrhythmias requires elucidating individual CaM variant effect on distinct channels. One key CaM regulatory target is the KCNQ1 (K V 7.1) voltage-gated potassium channel that underlie the I Ks current. Yet, relatively little is known as to how CaM variants interact with KCNQ1 or affect its function. Objective To observe how arrhythmia-associated CaM variants affect binding to KCNQ1, channel membrane trafficking, and KCNQ1 function. Methods and Results We combine a live-cell FRET binding assay, fluorescence trafficking assay, and functional electrophysiology to characterize >10 arrhythmia-associated CaM variants effect on KCNQ1. We identify one variant (G114W) that exhibits severely weakened binding to KCNQ1 but find that most other CaM variants interact with similar binding affinity to KCNQ1 when compared to CaM wild-type over physiological Ca 2+ ranges. We further identify several CaM variants that affect KCNQ1 and I Ks membrane trafficking and/or baseline current activation kinetics, thereby contextualizing KCNQ1 dysfunction in calmodulinopathy. Lastly, we delineate CaM variants with no effect on KCNQ1 function. Conclusions This study provides comprehensive functional data that reveal how CaM variants contribute to creating a pro-arrhythmic substrate by causing abnormal KCNQ1 membrane trafficking and current conduction. We find that CaM variant regulation of KCNQ1 is not uniform with effects varying from benign to significant loss of function. This study provides a new approach to collecting details of CaM binding that are key for understanding how CaM variants predispose patients to arrhythmia via the dysregulation of multiple cardiac ion channels.
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17
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Keefe JA, Moore OM, Ho KS, Wehrens XHT. Role of Ca 2+ in healthy and pathologic cardiac function: from normal excitation-contraction coupling to mutations that cause inherited arrhythmia. Arch Toxicol 2023; 97:73-92. [PMID: 36214829 PMCID: PMC10122835 DOI: 10.1007/s00204-022-03385-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 09/15/2022] [Indexed: 01/19/2023]
Abstract
Calcium (Ca2+) ions are a key second messenger involved in the rhythmic excitation and contraction of cardiomyocytes throughout the heart. Proper function of Ca2+-handling proteins is required for healthy cardiac function, whereas disruption in any of these can cause cardiac arrhythmias. This comprehensive review provides a broad overview of the roles of Ca2+-handling proteins and their regulators in healthy cardiac function and the mechanisms by which mutations in these proteins contribute to inherited arrhythmias. Major Ca2+ channels and Ca2+-sensitive regulatory proteins involved in cardiac excitation-contraction coupling are discussed, with special emphasis on the function of the RyR2 macromolecular complex. Inherited arrhythmia disorders including catecholaminergic polymorphic ventricular tachycardia, long QT syndrome, Brugada syndrome, short QT syndrome, and arrhythmogenic right-ventricular cardiomyopathy are discussed with particular emphasis on subtypes caused by mutations in Ca2+-handling proteins.
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Affiliation(s)
- Joshua A Keefe
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Oliver M Moore
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kevin S Ho
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA. .,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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18
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Calmodulin variant E140G associated with long QT syndrome impairs CaMKIIδ autophosphorylation and L-type calcium channel inactivation. J Biol Chem 2023; 299:102777. [PMID: 36496072 PMCID: PMC9830374 DOI: 10.1016/j.jbc.2022.102777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
Long QT syndrome (LQTS) is a human inherited heart condition that can cause life-threatening arrhythmia including sudden cardiac death. Mutations in the ubiquitous Ca2+-sensing protein calmodulin (CaM) are associated with LQTS, but the molecular mechanism by which these mutations lead to irregular heartbeats is not fully understood. Here, we use a multidisciplinary approach including protein biophysics, structural biology, confocal imaging, and patch-clamp electrophysiology to determine the effect of the disease-associated CaM mutation E140G on CaM structure and function. We present novel data showing that mutant-regulated CaMKIIδ kinase activity is impaired with a significant reduction in enzyme autophosphorylation rate. We report the first high-resolution crystal structure of a LQTS-associated CaM variant in complex with the CaMKIIδ peptide, which shows significant structural differences, compared to the WT complex. Furthermore, we demonstrate that the E140G mutation significantly disrupted Cav1.2 Ca2+/CaM-dependent inactivation, while cardiac ryanodine receptor (RyR2) activity remained unaffected. In addition, we show that the LQTS-associated mutation alters CaM's Ca2+-binding characteristics, secondary structure content, and interaction with key partners involved in excitation-contraction coupling (CaMKIIδ, Cav1.2, RyR2). In conclusion, LQTS-associated CaM mutation E140G severely impacts the structure-function relationship of CaM and its regulation of CaMKIIδ and Cav1.2. This provides a crucial insight into the molecular factors contributing to CaM-mediated arrhythmias with a central role for CaMKIIδ.
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19
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McCoy MD, Ullah A, Lederer WJ, Jafri MS. Understanding Calmodulin Variants Affecting Calcium-Dependent Inactivation of L-Type Calcium Channels through Whole-Cell Simulation of the Cardiac Ventricular Myocyte. Biomolecules 2022; 13:72. [PMID: 36671457 PMCID: PMC9855640 DOI: 10.3390/biom13010072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
Mutations in the calcium-sensing protein calmodulin (CaM) have been linked to two cardiac arrhythmia diseases, Long QT Syndrome 14 (LQT14) and Catecholaminergic Polymorphic Ventricular Tachycardia Type 4 (CPVT4), with varying degrees of severity. Functional characterization of the CaM mutants most strongly associated with LQT14 show a clear disruption of the calcium-dependent inactivation (CDI) of the L-Type calcium channel (LCC). CPVT4 mutants on the other hand are associated with changes in their affinity to the ryanodine receptor. In clinical studies, some variants have been associated with both CPVT4 and LQT15. This study uses simulations in a model for excitation-contraction coupling in the rat ventricular myocytes to understand how LQT14 variant might give the functional phenotype similar to CPVT4. Changing the CaM-dependent transition rate by a factor of 0.75 corresponding to the D96V variant and by a factor of 0.90 corresponding to the F142L or N98S variants, in a physiologically based stochastic model of the LCC prolonger, the action potential duration changed by a small amount in a cardiac myocyte but did not disrupt CICR at 1, 2, and 4 Hz. Under beta-adrenergic simulation abnormal excitation-contraction coupling was observed above 2 Hz pacing for the mutant CaM. The same conditions applied under beta-adrenergic stimulation led to the rapid onset of arrhythmia in the mutant CaM simulations. Simulations with the LQT14 mutations under the conditions of rapid pacing with beta-adrenergic stimulation drives the cardiac myocyte toward an arrhythmic state known as Ca2+ overload. These simulations provide a mechanistic link to a disease state for LQT14-associated mutations in CaM to yield a CPVT4 phenotype. The results show that small changes to the CaM-regulated inactivation of LCC promote arrhythmia and underscore the significance of CDI in proper heart function.
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Affiliation(s)
- Matthew D. McCoy
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
- Innovation Center for Biomedical Informatics, Department of Oncology, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, USA
| | - Aman Ullah
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
| | - W. Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
| | - M. Saleet Jafri
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
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20
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Bamgboye MA, Traficante MK, Owoyemi J, DiSilvestre D, Vieira DCO, Dick IE. Impaired Ca V1.2 inactivation reduces the efficacy of calcium channel blockers in the treatment of LQT8. J Mol Cell Cardiol 2022; 173:92-100. [PMID: 36272554 PMCID: PMC10583761 DOI: 10.1016/j.yjmcc.2022.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/12/2022] [Accepted: 10/16/2022] [Indexed: 11/23/2022]
Abstract
Mutations in the CaV1.2 L-type calcium channel can cause a profound form of long-QT syndrome known as long-QT type 8 (LQT8), which results in cardiac arrhythmias that are often fatal in early childhood. A growing number of such pathogenic mutations in CaV1.2 have been identified, increasing the need for targeted therapies. As many of these mutations reduce channel inactivation; resulting in excess Ca2+ entry during the action potential, calcium channel blockers (CCBs) would seem to represent a promising treatment option. Yet CCBs have been unsuccessful in the treatment of LQT8. Here, we demonstrate that this lack of efficacy likely stems from the impact of the mutations on CaV1.2 channel inactivation. As CCBs are known to preferentially bind to the inactivated state of the channel, mutation-dependent deficits in inactivation result in a decrease in use-dependent block of the mutant channel. Further, application of the CCB verapamil to induced pluripotent stem cell (iPSC) derived cardiomyocytes from an LQT8 patient demonstrates that this loss of use-dependent block translates to a lack of efficacy in correcting the LQT phenotype. As a growing number of channelopathic mutations demonstrate effects on channel inactivation, reliance on state-dependent blockers may leave a growing population of patients without a viable treatment option. This biophysical understanding of the interplay between inactivation deficits and state-dependent block may provide a new avenue to guide the development of improved therapies.
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Affiliation(s)
- Moradeke A Bamgboye
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Maria K Traficante
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Josiah Owoyemi
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Deborah DiSilvestre
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Daiana C O Vieira
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Ivy E Dick
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America.
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21
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Munk M, Villalobo E, Villalobo A, Berchtold MW. Differential expression of the three independent CaM genes coding for an identical protein: Potential relevance of distinct mRNA stability by different codon usage. Cell Calcium 2022; 107:102656. [DOI: 10.1016/j.ceca.2022.102656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/01/2022] [Accepted: 09/25/2022] [Indexed: 11/24/2022]
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22
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Zhao J, Segura E, Marsolais M, Parent L. A CACNA1C variant associated with cardiac arrhythmias provides mechanistic insights in the calmodulation of L-type Ca 2+ channels. J Biol Chem 2022; 298:102632. [PMID: 36273583 PMCID: PMC9691931 DOI: 10.1016/j.jbc.2022.102632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/12/2022] [Accepted: 10/15/2022] [Indexed: 11/07/2022] Open
Abstract
We recently reported the identification of a de novo single nucleotide variant in exon 9 of CACNA1C associated with prolonged repolarization interval. Recombinant expression of the glycine to arginine variant at position 419 produced a gain in the function of the L-type CaV1.2 channel with increased peak current density and activation gating but without significant decrease in the inactivation kinetics. We herein reveal that these properties are replicated by overexpressing calmodulin (CaM) with CaV1.2 WT and are reversed by exposure to the CaM antagonist W-13. Phosphomimetic (T79D or S81D), but not phosphoresistant (T79A or S81A), CaM surrogates reproduced the impact of CaM WT on the function of CaV1.2 WT. The increased channel activity of CaV1.2 WT following overexpression of CaM was found to arise in part from enhanced cell surface expression. In contrast, the properties of the variant remained unaffected by any of these treatments. CaV1.2 substituted with the α-helix breaking proline residue were more reluctant to open than CaV1.2 WT but were upregulated by phosphomimetic CaM surrogates. Our results indicate that (1) CaM and its phosphomimetic analogs promote a gain in the function of CaV1.2 and (2) the structural properties of the first intracellular linker of CaV1.2 contribute to its CaM-induced modulation. We conclude that the CACNA1C clinical variant mimics the increased activity associated with the upregulation of CaV1.2 by Ca2+-CaM, thus maintaining a majority of channels in a constitutively active mode that could ultimately promote ventricular arrhythmias.
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Affiliation(s)
- Juan Zhao
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
| | - Emilie Segura
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada
| | - Mireille Marsolais
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada
| | - Lucie Parent
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada,For correspondence: Lucie Parent
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23
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Westerlund AM, Sridhar A, Dahl L, Andersson A, Bodnar AY, Delemotte L. Markov state modelling reveals heterogeneous drug-inhibition mechanism of Calmodulin. PLoS Comput Biol 2022; 18:e1010583. [PMID: 36206305 PMCID: PMC9581412 DOI: 10.1371/journal.pcbi.1010583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/19/2022] [Accepted: 09/18/2022] [Indexed: 11/06/2022] Open
Abstract
Calmodulin (CaM) is a calcium sensor which binds and regulates a wide range of target-proteins. This implicitly enables the concentration of calcium to influence many downstream physiological responses, including muscle contraction, learning and depression. The antipsychotic drug trifluoperazine (TFP) is a known CaM inhibitor. By binding to various sites, TFP prevents CaM from associating to target-proteins. However, the molecular and state-dependent mechanisms behind CaM inhibition by drugs such as TFP are largely unknown. Here, we build a Markov state model (MSM) from adaptively sampled molecular dynamics simulations and reveal the structural and dynamical features behind the inhibitory mechanism of TFP-binding to the C-terminal domain of CaM. We specifically identify three major TFP binding-modes from the MSM macrostates, and distinguish their effect on CaM conformation by using a systematic analysis protocol based on biophysical descriptors and tools from machine learning. The results show that depending on the binding orientation, TFP effectively stabilizes features of the calcium-unbound CaM, either affecting the CaM hydrophobic binding pocket, the calcium binding sites or the secondary structure content in the bound domain. The conclusions drawn from this work may in the future serve to formulate a complete model of pharmacological modulation of CaM, which furthers our understanding of how these drugs affect signaling pathways as well as associated diseases. Calmodulin (CaM) is a calcium-sensing protein which makes other proteins dependent on the surrounding calcium concentration by binding to these proteins. Such protein-protein interactions with CaM are vital for calcium to control many physiological pathways within the cell. The antipsychotic drug trifluoperazine (TFP) inhibits CaM’s ability to bind and regulate other proteins. Here, we use molecular dynamics simulations together with Markov state modeling and machine learning to understand the structural and dynamical features by which TFP bound to the one domain of CaM prevents association to other proteins. We find that TFP encourages CaM to adopt a conformation that is like the one stabilized in absence of calcium: depending on the binding orientation of TFP, the drug indeed either affects the CaM hydrophobic binding pocket, the calcium binding sites or the secondary structure content in the domain. Understanding TFP binding is a first step towards designing better drugs targeting CaM.
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Affiliation(s)
- Annie M. Westerlund
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Akshay Sridhar
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Leo Dahl
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Alma Andersson
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
- Division of Gene Technology, Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Anna-Yaroslava Bodnar
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - Lucie Delemotte
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
- * E-mail:
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24
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Saleem A, Abbas MK, Wang Y, Lan F. hPSC gene editing for cardiac disease therapy. Pflugers Arch 2022; 474:1123-1132. [PMID: 36163402 DOI: 10.1007/s00424-022-02751-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/09/2022] [Accepted: 09/18/2022] [Indexed: 11/26/2022]
Abstract
Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide. However, the lack of human cardiomyocytes with proper genetic backgrounds limits the study of disease mechanisms. Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have significantly advanced the study of these conditions. Moreover, hPSC-CMs made it easy to study CVDs using genome-editing techniques. This article discusses the applications of these techniques in hPSC for studying CVDs. Recently, several genome-editing systems have been used to modify hPSCs, including zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeat-associated protein 9 (CRISPR/Cas9). We focused on the recent advancement of genome editing in hPSCs, which dramatically improved the efficiency of the cell-based mechanism study and therapy for cardiac diseases.
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Affiliation(s)
- Amina Saleem
- Beijing Laboratory for Cardiovascular Precision Medicine, MOE Key Laboratory of Medical Engineering for Cardiovascular Diseases, MOE Key Laboratory of Remodeling Related Cardiovascular Disease, Beijing Collaborative Innovation Center for Cardiovascular Disorders, Research Institute Building, Beijinj Anzhen Hospital, Capital Medical University, Room 319, 2 Anzhen Road, Chaoyang District, Beijing, Beijing, 100029, China
| | - Muhammad Khawar Abbas
- BHMS Department, University College of Conventional Medicine, Faculty of Medicine and Allied Health Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Yongming Wang
- The State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, 200438, China
- The Key Lab of Reproduction Regulation of NPFPC in SIPPR, Institute of Reproduction & Development in Obstetrics & Gynecology Hospital, Fudan University, Shanghai, 200011, China
| | - Feng Lan
- Beijing Laboratory for Cardiovascular Precision Medicine, MOE Key Laboratory of Medical Engineering for Cardiovascular Diseases, MOE Key Laboratory of Remodeling Related Cardiovascular Disease, Beijing Collaborative Innovation Center for Cardiovascular Disorders, Research Institute Building, Beijinj Anzhen Hospital, Capital Medical University, Room 319, 2 Anzhen Road, Chaoyang District, Beijing, Beijing, 100029, China.
- Fuwai Hospital Chinese Academy of Medical Sciences, Shenzhen, Shenzhen Key Laboratory of Cardiovascular Disease, State Key Laboratory of Cardiovascular Disease, Key Laboratory of Pluripotent Stem Cells in Cardiac Repair and Regeneration, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Beijing, 100029, China.
- National Health Commission Key Laboratory of Cardiovascular Regenerative Medicine, Fuwai Central-China Hospital, Central-China Branch of National Center for Cardiovascular Diseases, Zhengzhou, Beijing, 100037, China.
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25
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Novaes GM, Alvarez-Lacalle E, Muñoz SA, dos Santos RW. An ensemble of parameters from a robust Markov-based model reproduces L-type calcium currents from different human cardiac myocytes. PLoS One 2022; 17:e0266233. [PMID: 35381041 PMCID: PMC8982880 DOI: 10.1371/journal.pone.0266233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 03/16/2022] [Indexed: 11/18/2022] Open
Abstract
The development of modeling structures at the channel level that can integrate subcellular and cell models and properly reproduce different experimental data is of utmost importance in cardiac electrophysiology. In contrast to gate-based models, Markov Chain models are well suited to promote the integration of the subcellular level of the cardiomyocyte to the whole cell. In this paper, we develop Markov Chain models for the L-type Calcium current that can reproduce the electrophysiology of two established human models for the ventricular and Purkinje cells. In addition, instead of presenting a single set of parameters, we present a collection of set of parameters employing Differential Evolution algorithms that can properly reproduce very different protocol data. We show the importance of using an ensemble of a set of parameter values to obtain proper results when considering a second protocol that suppresses calcium inactivation and mimics a pathological condition. We discuss how model discrepancy, data availability, and parameter identifiability can influence the choice of the size of the collection. In summary, we have modified two cardiac models by proposing new Markov Chain models for the L-type Calcium. We keep the original whole-cell dynamics by reproducing the same characteristic action potential and calcium dynamics, whereas the Markov chain-based description of the L-type Calcium channels allows novel small spatial scale simulations of subcellular processes. Finally, the use of collections of parameters was crucial for addressing model discrepancy, identifiability issues, and avoiding fitting parameters overly precisely, i.e., overfitting.
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Affiliation(s)
- Gustavo Montes Novaes
- Graduate Program in Computational Modeling, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
- Department of Physics, Universitat Politècnica de Catalunya-BarcelonaTech, Barcelona, Spain
- Department of Computation and Mechanics, Federal Center of Technological Education of Minas Gerais, Leopoldina, MG, Brazil
- * E-mail:
| | | | - Sergio Alonso Muñoz
- Department of Physics, Universitat Politècnica de Catalunya-BarcelonaTech, Barcelona, Spain
| | - Rodrigo Weber dos Santos
- Graduate Program in Computational Modeling, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
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26
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Colecraft HM, Trimmer JS. Controlling ion channel function with renewable recombinant antibodies. J Physiol 2022; 600:2023-2036. [PMID: 35238051 PMCID: PMC9058206 DOI: 10.1113/jp282403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/11/2022] [Indexed: 11/08/2022] Open
Abstract
Selective ion channel modulators play a critical role in physiology in defining the contribution of specific ion channels to physiological function and as proof of concept for novel therapeutic strategies. Antibodies are valuable research tools that have broad uses including defining the expression and localization of ion channels in native tissue, and capturing ion channel proteins for subsequent analyses. In this review, we detail how renewable and recombinant antibodies can be used to control ion channel function. We describe the different forms of renewable and recombinant antibodies that have been used and the mechanisms by which they modulate ion channel function. We highlight the use of recombinant antibodies that are expressed intracellularly (intrabodies) as genetically-encoded tools to control ion channel function. We also offer perspectives of avenues of future research that may be opened by the application of emerging technologies for engineering recombinant antibodies for enhanced utility in ion channel research. Overall, this review provides insights that may help stimulate and guide interested researchers to develop and incorporate renewable and recombinant antibodies as valuable tools to control ion channel function. Abstract figure legend Two different approaches for controlling ion channel function using renewable recombinant antibodies. On the left, an externally applied intact IgG antibody (purple) binds to an extracellular domain of an ion channel (light blue) to control ion channel function. On the right, a genetically-encoded intrabody, in this example a camelid nanobody (green) fused to an effector molecule (red) binds to an intracellular auxiliary subunit of an ion channel (dark blue) to control ion channel function. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
| | - James S Trimmer
- Department of Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA, 95616, USA
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Kato K, Isbell HM, Fressart V, Denjoy I, Debbiche A, Itoh H, Poinsot J, George AL, Coulombe A, Shea MA, Guicheney P. Novel CALM3 Variant Causing Calmodulinopathy With Variable Expressivity in a 4-Generation Family. Circ Arrhythm Electrophysiol 2022; 15:e010572. [PMID: 35225649 DOI: 10.1161/circep.121.010572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND CaM (calmodulin), encoded by 3 separate genes (CALM1, CALM2, and CALM3), is a multifunctional Ca2+-binding protein involved in many signal transduction events including ion channel regulation. CaM variants may present with early-onset long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia, or sudden cardiac death. Most reported variants occurred de novo. We identified a novel CALM3 variant, p.Asn138Lys (N138K), in a 4-generation family segregating with LQTS. The aim of this study was to elucidate its pathogenicity and to compare it with that of p.D130G-CaM-a variant associated with a severe LQTS phenotype. METHODS We performed whole exome sequencing for a large, 4-generation family affected by LQTS. To assess the effect of the detected CALM3 variant, the intrinsic Ca2+-binding affinity was measured by stoichiometric Ca2+ titrations and equilibrium titrations. L-type Ca2+ and slow delayed rectifier potassium currents (ICaL and IKs) were recorded by whole-cell patch-clamp. Cav1.2 and Kv7.1 membrane expression were determined by optical fluorescence assays. RESULTS We identified 14 p.N138K-CaM carriers in a family where 2 sudden deaths occurred in children. Several members were only mildly affected compared with CaM-LQTS patients to date described in literature. The intrinsic Ca2+-binding affinity of the CaM C-terminal domain was 10-fold lower for p.N138K-CaM compared with wild-type-CaM. ICaL inactivation was slowed in cells expressing p.N138K-CaM but less than in p.D130G-CaM cells. Unexpectedly, a larger IKs current density was observed in cells expressing p.N138K-CaM, but not for p.D130G-CaM, compared with wild-type-CaM. CONCLUSIONS The p.N138K CALM3 variant impairs Ca2+-binding affinity of CaM and ICaL inactivation but potentiates IKs. The variably expressed phenotype of this variant compared with previously published de novo LQTS-CaM variants is likely explained by a milder impairment of ICaL inactivation combined with IKs augmentation.
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Affiliation(s)
- Koichi Kato
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France (K.K., V.F., I.D., A.D., A.C., P.G.).,Department of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Japan (K.K.)
| | - Holly M Isbell
- Department of Biochemistry, Carver College of Medicine, University of Iowa (H.M.I., M.A.S.)
| | - Véronique Fressart
- AP-HP, Pitié-Salpêtrière Hospital, Functional Unit of Cardiogenetics and Myogenetics, Paris, France (V.F.)
| | - Isabelle Denjoy
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France (K.K., V.F., I.D., A.D., A.C., P.G.).,Cardiology Department, Referring Center for Heritable or Rare Cardiac Diseases, AP-HP, Bichat Hospital, HUPNVS, Referring Center for Rare Cardiac Diseases, Sorbonne University, Paris, France (I.D.)
| | - Amal Debbiche
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France (K.K., V.F., I.D., A.D., A.C., P.G.)
| | - Hideki Itoh
- Division of Patient Safety, Hiroshima University Hospital, Japan (H.I.)
| | - Jacques Poinsot
- Unité de cardio-pediatrie, service de medecine pediatrique, Centre Hospitalier Universitaire de Tours, Tours, France (J.P.)
| | - Alfred L George
- Department of Pharmacology Northwestern University Feinberg School of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (A.L.G.)
| | - Alain Coulombe
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France (K.K., V.F., I.D., A.D., A.C., P.G.)
| | - Madeline A Shea
- Department of Biochemistry, Carver College of Medicine, University of Iowa (H.M.I., M.A.S.)
| | - Pascale Guicheney
- Sorbonne Université, Inserm, Research Unit on Cardiovascular and Metabolic Diseases, UMRS-1166, Paris, France (K.K., V.F., I.D., A.D., A.C., P.G.)
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28
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Tang JKK, Rabkin SW. Hypocalcemia-Induced QT Interval Prolongation. Cardiology 2022; 147:191-195. [PMID: 35078204 DOI: 10.1159/000515985] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 03/10/2021] [Indexed: 11/19/2022]
Abstract
An 87-year-old man with a history of transcatheter aortic valve replacement, pulmonary hypertension, diastolic dysfunction with preserved systolic function, and myelofibrosis had a 12-lead ECG showed a prolonged QT interval of 508 ms with heart-rate correction placing it in the 99th percentile of the population. Reduction in the dose of furosemide and calcium supplementation increased serum calcium and shortened the QT interval. This case provides an opportunity to examine newer concepts for the understanding of the mechanisms by which hypocalcemia might induce QT prolongation. Hypocalcemia likely produces corrected QT interval prolongation primarily through a calcium-dependent inactivation (CDI) mechanism on the L-type calcium channel (LTCC). Lower extracellular calcium leads to a decreased ICaL, subsequently causing intracellular calcium to take longer to reach the critical threshold to induce CDI of the LTCC. The resulting prolonged repolarization of the ventricular myocyte can lead to early after-depolarizations and ensuing life-threatening ventricular arrhythmias. Genetic polymorphisms in Ca2+-binding protein calmodulin which can prolong QT, underscore the role for disturbances of intracellular myocardial calcium handling in arrhythmogenesis. Hypocalcemia is an under-recognized cause of QT prolongation and should be taken into careful consideration in patients presenting with incidental findings of a prolonged QT interval.
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Affiliation(s)
- Jacky K K Tang
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Simon W Rabkin
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
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29
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Lin DJ, Lee WS, Chien YC, Chen TY, Yang KT. The link between abnormalities of calcium handling proteins and catecholaminergic polymorphic ventricular tachycardia. Tzu Chi Med J 2021; 33:323-331. [PMID: 34760626 PMCID: PMC8532576 DOI: 10.4103/tcmj.tcmj_288_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/09/2021] [Accepted: 03/03/2021] [Indexed: 01/18/2023] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT), a rare autosomal dominant or recessive disease, usually results in syncope or sudden cardiac death. Most CPVT patients do not show abnormal cardiac structure and electrocardiogram features and symptoms, usually onset during adrenergically mediated physiological conditions. CPVT tends to occur at a younger age and is not easy to be diagnosed and managed. The main cause of CPVT is associated with mishandling Ca2+ in cardiomyocytes. Intracellular Ca2+ is strictly controlled by a protein located in the sarcoplasm reticulum (SR), such as ryanodine receptor, histidine-rich Ca2+-binding protein, triadin, and junctin. Mutation in these proteins results in misfolding or malfunction of these proteins, thereby affecting their Ca2+-binding affinity, and subsequently disturbs Ca2+ homeostasis during excitation–contraction coupling (E-C coupling). Furthermore, transient disturbance of Ca2+ homeostasis increases membrane potential and causes Ca2+ store overload-induced Ca2+ release, which in turn leads to delayed after depolarization and arrhythmia. Previous studies have focused on the interaction between ryanodine receptors and protein kinase or phosphatase in the cytosol. However, recent studies showed the regulation signaling for ryanodine receptor not only from the cytosol but also within the SR. The changing of Ca2+ concentration is critical for protein interaction inside the SR which changes protein conformation to regulate the open probability of ryanodine receptors. Thus, it influences the threshold of Ca2+ released from the SR, making it easier to release Ca2+ during E-C coupling. In this review, we briefly discuss how Ca2+ handling protein variations affect the Ca2+ handling in CPVT.
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Affiliation(s)
- Ding-Jyun Lin
- School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Wen-Sen Lee
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | | | - Tsung-Yu Chen
- School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Kun-Ta Yang
- Master Program in Medical Physiology, School of Medicine, Tzu Chi University, Hualien, Taiwan.,Department of Physiology, School of Medicine, Tzu Chi University, Hualien, Taiwan
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30
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Tsai WC, Chen PS, Rubart M. Calmodulinopathy in inherited arrhythmia syndromes. Tzu Chi Med J 2021; 33:339-344. [PMID: 34760628 PMCID: PMC8532581 DOI: 10.4103/tcmj.tcmj_182_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/02/2020] [Accepted: 10/07/2020] [Indexed: 11/04/2022] Open
Abstract
Calmodulin (CaM) is a ubiquitous intracellular calcium sensor that controls and regulates key cellular functions. In all vertebrates, three CaM genes located on separate chromosomes encode an identical 149 amino acid protein, implying an extraordinarily high level of evolutionary importance and suggesting that CaM mutations would be possibly fatal. Inherited arrhythmia syndromes comprise a spectrum of primary electrical disorders caused by mutations in genes encoding ion channels or associated proteins leading to various cardiac arrhythmias, unexplained syncope, and sudden cardiac death. CaM mutations have emerged as an independent entity among inherited arrhythmia syndromes, referred to as calmodulinopathies. The most common clinical presentation associated with calmodulinopathy is congenital long QT syndrome, followed by catecholaminergic polymorphic ventricular tachycardia, both of which significantly increase the possibility of repeated syncope, lethal arrhythmic events, and sudden cardiac death, especially in young individuals. Here, we aim to give an overview of biochemical and structural characteristics of CaM and progress toward updating current known CaM mutations and associated clinical phenotypes. We also review the possible mechanisms underlying calmodulinopathy, based on several key in vitro studies. We expect that further experimental studies are needed to explore the complexity of calmodulinopathy.
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Affiliation(s)
- Wen-Chin Tsai
- Department of Cardiology, Cardiovascular Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, and Tzu Chi University, Hualien, Taiwan
| | - Peng-Sheng Chen
- Department of Cardiology, Cedar-Sinai Medical Center, Los Angeles, CA, USA.,Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Michael Rubart
- Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Pediatrics, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
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31
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Ledford HA, Park S, Muir D, Woltz RL, Ren L, Nguyen PT, Sirish P, Wang W, Sihn CR, George AL, Knollmann BC, Yamoah EN, Yarov-Yarovoy V, Zhang XD, Chiamvimonvat N. Different arrhythmia-associated calmodulin mutations have distinct effects on cardiac SK channel regulation. J Gen Physiol 2021; 152:211546. [PMID: 33211795 PMCID: PMC7681919 DOI: 10.1085/jgp.202012667] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/25/2020] [Accepted: 10/19/2020] [Indexed: 12/21/2022] Open
Abstract
Calmodulin (CaM) plays a critical role in intracellular signaling and regulation of Ca2+-dependent proteins and ion channels. Mutations in CaM cause life-threatening cardiac arrhythmias. Among the known CaM targets, small-conductance Ca2+-activated K+ (SK) channels are unique, since they are gated solely by beat-to-beat changes in intracellular Ca2+. However, the molecular mechanisms of how CaM mutations may affect the function of SK channels remain incompletely understood. To address the structural and functional effects of these mutations, we introduced prototypical human CaM mutations in human induced pluripotent stem cell–derived cardiomyocyte-like cells (hiPSC-CMs). Using structural modeling and molecular dynamics simulation, we demonstrate that human calmodulinopathy-associated CaM mutations disrupt cardiac SK channel function via distinct mechanisms. CaMD96V and CaMD130G mutants reduce SK currents through a dominant-negative fashion. By contrast, specific mutations replacing phenylalanine with leucine result in conformational changes that affect helix packing in the C-lobe, which disengage the interactions between apo-CaM and the CaM-binding domain of SK channels. Distinct mutant CaMs may result in a significant reduction in the activation of the SK channels, leading to a decrease in the key Ca2+-dependent repolarization currents these channels mediate. The findings in this study may be generalizable to other interactions of mutant CaMs with Ca2+-dependent proteins within cardiac myocytes.
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Affiliation(s)
- Hannah A Ledford
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA
| | - Seojin Park
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, NV
| | - Duncan Muir
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA
| | - Ryan L Woltz
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA
| | - Lu Ren
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA
| | - Phuong T Nguyen
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, CA
| | - Padmini Sirish
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA
| | - Wenying Wang
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, NV
| | - Choong-Ryoul Sihn
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, NV
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Björn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, School of Medicine, Vanderbilt University, Nashville, TN
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, NV
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, CA
| | - Xiao-Dong Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA.,Department of Veterans Affairs, Northern California Health Care System, Mather, CA
| | - Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA.,Department of Veterans Affairs, Northern California Health Care System, Mather, CA
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32
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Berchtold MW, Munk M, Kulej K, Porth I, Lorentzen L, Panina S, Zacharias T, Larsen MR, la Cour JM. The heart arrhythmia-linked D130G calmodulin mutation causes premature inhibitory autophosphorylation of CaMKII. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119119. [PMID: 34391760 DOI: 10.1016/j.bbamcr.2021.119119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 10/20/2022]
Abstract
The Ca2+/calmodulin (CaM)-dependent kinase II (CaMKII) is well known for transmitting Ca2+-signals, which leads to a multitude of physiological responses. Its functionality is believed to involve CaMKII holoenzyme dynamics where trans-autophosphorylation of the crucial phosphorylation site, T286 occurs. Phosphorylation of this site does not occur when stimulated exclusively with the arrhythmia associated D130G mutant form of CaM in vitro. Here, we present evidence that the loss-of-CaMKII function correlates with premature phosphorylation of its inhibitory phosphosite T306 in CaMKIIα and T307 in CaMKIIδ as this site was up to 20-fold more phosphorylated in the presence of D130G CaM compared to wildtype CaM. Indeed, changing this phosphosite to a non-phosphorylatable alanine reversed the inhibitory effect of D130G both in vitro and in live cell experiments. In addition, several phosphosites with so far undescribed functions directing the Ca2+-sensitivity of the CaMKII sensor were also affected by the presence of the D130G mutation implicating a role of several additional autophosphosites (besides T286 and T306/T307) so far not known to regulate CaMKII Ca2+ sensitivity. Furthermore, we show that introducing a D130G mutation in the CALM2 gene of the P19CL6 pluripotent mouse embryonic carcinoma cell line using CRISPR/Cas9 decreased the spontaneous beat frequency compared to wildtype cells when differentiated into cardiomyocytes supporting an alteration of cardiomyocyte physiology caused by this point mutation. In conclusion, our observations shed for the first time light on how the D130G CaM mutation interferes with the function of CaMKII and how it affects the beating frequency of cardiomyocyte-like cells.
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Affiliation(s)
| | - Mads Munk
- Department of Biology, University of Copenhagen, Denmark
| | - Katarzyna Kulej
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Denmark; Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
| | - Isabel Porth
- Department of Biology, University of Copenhagen, Denmark
| | - Lasse Lorentzen
- Department of Biology, University of Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Svetlana Panina
- Department of Biology, University of Copenhagen, Denmark; MonTa Biosciences ApS, Diplomvej 381, 2800 kgs Lyngby, Denmark
| | | | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Denmark
| | - Jonas M la Cour
- Department of Biology, University of Copenhagen, Denmark; ChemoMetec A/S, Gydevang 43, 3450 Lillerød, Denmark
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33
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Woll KA, Van Petegem F. Calcium Release Channels: Structure and Function of IP3 Receptors and Ryanodine Receptors. Physiol Rev 2021; 102:209-268. [PMID: 34280054 DOI: 10.1152/physrev.00033.2020] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca2+-release channels are giant membrane proteins that control the release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. The two members, ryanodine receptors (RyRs) and inositol-1,4,5-trisphosphate Receptors (IP3Rs), are evolutionarily related and are both activated by cytosolic Ca2+. They share a common architecture, but RyRs have evolved additional modules in the cytosolic region. Their massive size allows for the regulation by tens of proteins and small molecules, which can affect the opening and closing of the channels. In addition to Ca2+, other major triggers include IP3 for the IP3Rs, and depolarization of the plasma membrane for a particular RyR subtype. Their size has made them popular targets for study via electron microscopic methods, with current structures culminating near 3Å. The available structures have provided many new mechanistic insights int the binding of auxiliary proteins and small molecules, how these can regulate channel opening, and the mechanisms of disease-associated mutations. They also help scrutinize previously proposed binding sites, as some of these are now incompatible with the structures. Many questions remain around the structural effects of post-translational modifications, additional binding partners, and the higher-order complexes these channels can make in situ. This review summarizes our current knowledge about the structures of Ca2+-release channels and how this informs on their function.
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Affiliation(s)
- Kellie A Woll
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
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34
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Mechanisms underlying pathological Ca 2+ handling in diseases of the heart. Pflugers Arch 2021; 473:331-347. [PMID: 33399957 PMCID: PMC10070045 DOI: 10.1007/s00424-020-02504-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Cardiomyocyte contraction relies on precisely regulated intracellular Ca2+ signaling through various Ca2+ channels and transporters. In this article, we will review the physiological regulation of Ca2+ handling and its role in maintaining normal cardiac rhythm and contractility. We discuss how inherited variants or acquired defects in Ca2+ channel subunits contribute to the development or progression of diseases of the heart. Moreover, we highlight recent insights into the role of protein phosphatase subunits and striated muscle preferentially expressed protein kinase (SPEG) in atrial fibrillation, heart failure, and cardiomyopathies. Finally, this review summarizes current drug therapies and new advances in genome editing as therapeutic strategies for the cardiac diseases caused by aberrant intracellular Ca2+ signaling.
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35
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Gong D, Yan N, Ledford HA. Structural Basis for the Modulation of Ryanodine Receptors. Trends Biochem Sci 2020; 46:489-501. [PMID: 33353849 DOI: 10.1016/j.tibs.2020.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 12/11/2022]
Abstract
Historically, ryanodine receptors (RyRs) have presented unique challenges for high-resolution structural determination despite long-standing interest in their role in excitation-contraction coupling. Owing to their large size (nearly 2.2 MDa), high-resolution structures remained elusive until the advent of cryogenic electron microscopy (cryo-EM) techniques. In recent years, structures for both RyR1 and RyR2 have been solved at near-atomic resolution. Furthermore, recent reports have delved into their more complex structural associations with key modulators - proteins such as the dihydropyridine receptor (DHPR), FKBP12/12.6, and calmodulin (CaM), as well as ions and small molecules including Ca2+, ATP, caffeine, and PCB95. This review addresses the modulation of RyR1 and RyR2, in addition to the impact of such discoveries on intracellular Ca2+ dynamics and biophysical properties.
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Affiliation(s)
- Deshun Gong
- Zhejiang Provincial Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province/Key Laboratory of Growth Regulation and Transformation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang Province, China.
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Hannah A Ledford
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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36
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Brohus M, Arsov T, Wallace DA, Jensen HH, Nyegaard M, Crotti L, Adamski M, Zhang Y, Field MA, Athanasopoulos V, Baró I, Ribeiro de Oliveira-Mendes BB, Redon R, Charpentier F, Raju H, DiSilvestre D, Wei J, Wang R, Rafehi H, Kaspi A, Bahlo M, Dick IE, Chen SRW, Cook MC, Vinuesa CG, Overgaard MT, Schwartz PJ. Infanticide vs. inherited cardiac arrhythmias. Europace 2020; 23:441-450. [PMID: 33200177 PMCID: PMC7947592 DOI: 10.1093/europace/euaa272] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 08/12/2020] [Indexed: 01/28/2023] Open
Abstract
AIMS In 2003, an Australian woman was convicted by a jury of smothering and killing her four children over a 10-year period. Each child died suddenly and unexpectedly during a sleep period, at ages ranging from 19 days to 18 months. In 2019 we were asked to investigate if a genetic cause could explain the children's deaths as part of an inquiry into the mother's convictions. METHODS AND RESULTS Whole genomes or exomes of the mother and her four children were sequenced. Functional analysis of a novel CALM2 variant was performed by measuring Ca2+-binding affinity, interaction with calcium channels and channel function. We found two children had a novel calmodulin variant (CALM2 G114R) that was inherited maternally. Three genes (CALM1-3) encode identical calmodulin proteins. A variant in the corresponding residue of CALM3 (G114W) was recently reported in a child who died suddenly at age 4 and a sibling who suffered a cardiac arrest at age 5. We show that CALM2 G114R impairs calmodulin's ability to bind calcium and regulate two pivotal calcium channels (CaV1.2 and RyR2) involved in cardiac excitation contraction coupling. The deleterious effects of G114R are similar to those produced by G114W and N98S, which are considered arrhythmogenic and cause sudden cardiac death in children. CONCLUSION A novel functional calmodulin variant (G114R) predicted to cause idiopathic ventricular fibrillation, catecholaminergic polymorphic ventricular tachycardia, or mild long QT syndrome was present in two children. A fatal arrhythmic event may have been triggered by their intercurrent infections. Thus, calmodulinopathy emerges as a reasonable explanation for a natural cause of their deaths.
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Affiliation(s)
- Malene Brohus
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
| | - Todor Arsov
- Department of Immunology and Infectious Disease, Centre for Personalised Immunology, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Canberra, Acton 2601, Australia,Department of Pediatrics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - David A Wallace
- Department of Immunology and Infectious Disease, Centre for Personalised Immunology, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Canberra, Acton 2601, Australia
| | - Helene Halkjær Jensen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
| | - Mette Nyegaard
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Lia Crotti
- Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Via Pier Lombardo, 22, 20135 Milan, Italy,Department of Cardiovascular, Neural and Metabolic Sciences, Istituto Auxologico Italiano, IRCCS, San Luca Hospital, Milan, Italy,Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Marcin Adamski
- Biology Teaching and Learning Centre, Research School of Biology and John Curtin School of Medical Research, The Australian National University, Canberra, Acton 2601, Australia
| | - Yafei Zhang
- NGS Team, Australian Phenomics Facility, John Curtin School of Medical Research, Australian National University, Canberra, Acton 2601, Australia
| | - Matt A Field
- Department of Immunology and Infectious Disease, Centre for Personalised Immunology, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Canberra, Acton 2601, Australia,Centre for Tropical Bioinformatics and Molecular Biology, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland 4878, Australia
| | - Vicki Athanasopoulos
- Department of Immunology and Infectious Disease, Centre for Personalised Immunology, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Canberra, Acton 2601, Australia
| | - Isabelle Baró
- Université de Nantes, CNRS, INSERM, L’institut du Thorax, F-44000 Nantes, France
| | | | - Richard Redon
- Université de Nantes, CNRS, INSERM, L’institut du Thorax, F-44000 Nantes, France
| | - Flavien Charpentier
- Université de Nantes, CNRS, INSERM, L’institut du Thorax, F-44000 Nantes, France
| | - Hariharan Raju
- Cardiology Department, Faculty of Medicine, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Deborah DiSilvestre
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jinhong Wei
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ruiwu Wang
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Haloom Rafehi
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Royal Parade, Parkville, Victoria 3052, Australia,Department of Medical Biology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Antony Kaspi
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Royal Parade, Parkville, Victoria 3052, Australia,Department of Medical Biology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Royal Parade, Parkville, Victoria 3052, Australia,Department of Medical Biology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Ivy E Dick
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Sui Rong Wayne Chen
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Matthew C Cook
- Department of Immunology and Infectious Disease, Centre for Personalised Immunology, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Canberra, Acton 2601, Australia
| | - Carola G Vinuesa
- Department of Immunology and Infectious Disease, Centre for Personalised Immunology, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Canberra, Acton 2601, Australia,Corresponding authors. +39 0255000408/9. E-mail address: (P.J.S.); Tel +45 9940 8525. E-mail address: (M.T.O.); Tel +61 432130556. E-mail address: (C.G.V.)
| | - Michael Toft Overgaard
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark,Corresponding authors. +39 0255000408/9. E-mail address: (P.J.S.); Tel +45 9940 8525. E-mail address: (M.T.O.); Tel +61 432130556. E-mail address: (C.G.V.)
| | - Peter J Schwartz
- Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Via Pier Lombardo, 22, 20135 Milan, Italy,Corresponding authors. +39 0255000408/9. E-mail address: (P.J.S.); Tel +45 9940 8525. E-mail address: (M.T.O.); Tel +61 432130556. E-mail address: (C.G.V.)
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Crotti L, Spazzolini C, Tester DJ, Ghidoni A, Baruteau AE, Beckmann BM, Behr ER, Bennett JS, Bezzina CR, Bhuiyan ZA, Celiker A, Cerrone M, Dagradi F, De Ferrari GM, Etheridge SP, Fatah M, Garcia-Pavia P, Al-Ghamdi S, Hamilton RM, Al-Hassnan ZN, Horie M, Jimenez-Jaimez J, Kanter RJ, Kaski JP, Kotta MC, Lahrouchi N, Makita N, Norrish G, Odland HH, Ohno S, Papagiannis J, Parati G, Sekarski N, Tveten K, Vatta M, Webster G, Wilde AAM, Wojciak J, George AL, Ackerman MJ, Schwartz PJ. Calmodulin mutations and life-threatening cardiac arrhythmias: insights from the International Calmodulinopathy Registry. Eur Heart J 2020; 40:2964-2975. [PMID: 31170290 DOI: 10.1093/eurheartj/ehz311] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/06/2019] [Accepted: 04/29/2019] [Indexed: 12/12/2022] Open
Abstract
AIMS Calmodulinopathies are rare life-threatening arrhythmia syndromes which affect mostly young individuals and are, caused by mutations in any of the three genes (CALM 1-3) that encode identical calmodulin proteins. We established the International Calmodulinopathy Registry (ICalmR) to understand the natural history, clinical features, and response to therapy of patients with a CALM-mediated arrhythmia syndrome. METHODS AND RESULTS A dedicated Case Report File was created to collect demographic, clinical, and genetic information. ICalmR has enrolled 74 subjects, with a variant in the CALM1 (n = 36), CALM2 (n = 23), or CALM3 (n = 15) genes. Sixty-four (86.5%) were symptomatic and the 10-year cumulative mortality was 27%. The two prevalent phenotypes are long QT syndrome (LQTS; CALM-LQTS, n = 36, 49%) and catecholaminergic polymorphic ventricular tachycardia (CPVT; CALM-CPVT, n = 21, 28%). CALM-LQTS patients have extremely prolonged QTc intervals (594 ± 73 ms), high prevalence (78%) of life-threatening arrhythmias with median age at onset of 1.5 years [interquartile range (IQR) 0.1-5.5 years] and poor response to therapies. Most electrocardiograms (ECGs) show late onset peaked T waves. All CALM-CPVT patients were symptomatic with median age of onset of 6.0 years (IQR 3.0-8.5 years). Basal ECG frequently shows prominent U waves. Other CALM-related phenotypes are idiopathic ventricular fibrillation (IVF, n = 7), sudden unexplained death (SUD, n = 4), overlapping features of CPVT/LQTS (n = 3), and predominant neurological phenotype (n = 1). Cardiac structural abnormalities and neurological features were present in 18 and 13 patients, respectively. CONCLUSION Calmodulinopathies are largely characterized by adrenergically-induced life-threatening arrhythmias. Available therapies are disquietingly insufficient, especially in CALM-LQTS. Combination therapy with drugs, sympathectomy, and devices should be considered.
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Affiliation(s)
- Lia Crotti
- Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Milan, Italy.,Istituto Auxologico Italiano, IRCCS, Laboratory of Cardiovascular Genetics, Milan, Italy.,Istituto Auxologico Italiano, IRCCS, Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy.,Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy.,Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart
| | - Carla Spazzolini
- Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Milan, Italy.,Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart
| | - David J Tester
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA.,Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Alice Ghidoni
- Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Milan, Italy.,Istituto Auxologico Italiano, IRCCS, Laboratory of Cardiovascular Genetics, Milan, Italy.,Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart
| | - Alban-Elouen Baruteau
- Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart.,L'Institut du Thorax, INSERM, CNRS, UNIV Nantes, CHU Nantes, Nantes, France.,Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Britt-Maria Beckmann
- Department of Medicine I, Klinikum Grosshadern, Ludwig-Maximilians University, Munich, Germany
| | - Elijah R Behr
- Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart.,Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | | | - Connie R Bezzina
- Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart.,Amsterdam UMC, University of Amsterdam, Heart Center; Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Zahurul A Bhuiyan
- Unité de Recherche Cardiogénétique, Service de Médecine Génétique, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Alpay Celiker
- Department of Pediatric Cardiology, Koc University School of Medicine, Istanbul, Turkey
| | - Marina Cerrone
- Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, NY, USA
| | - Federica Dagradi
- Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Milan, Italy.,Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart
| | - Gaetano M De Ferrari
- Division of Cardiology, "Città della Salute e della Scienza di Torino" Hospital, Department of Medical Sciences, University of Turin, Italy.,PhD Program in Translational Medicine, Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Susan P Etheridge
- Division of Pediatric Cardiology, Department of Pediatrics, University of Utah and Primary Children's Hospital, Salt Lake City, UT, USA
| | - Meena Fatah
- The Labatt Family Heart Centre and Pediatrics (Cardiology), The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - Pablo Garcia-Pavia
- Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart.,Inherited Cardiac Diseases Unit, Department of Cardiology, Hospital Universitario Puerta de Hierro, CIBERCV, Madrid, Spain.,University Francisco de Vitoria (UFV), Pozuelo de Alarcon, Spain
| | - Saleh Al-Ghamdi
- Cardiac Sciences Department, Section of Pediatric Cardiology, King Abdulaziz Cardiac Center, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Robert M Hamilton
- The Labatt Family Heart Centre and Pediatrics (Cardiology), The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - Zuhair N Al-Hassnan
- Cardiovascular Genetic Program, Department of Medical Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Minoru Horie
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Juan Jimenez-Jaimez
- Cardiology Department, Virgen de las Nieves University Hospital, Granada, Spain
| | | | - Juan P Kaski
- Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart.,Centre for Inherited Cardiovascular Diseases, Great Ormond Street Hospital, London, UK.,Institute of Cardiovascular Science, University College London, London, UK
| | - Maria-Christina Kotta
- Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Milan, Italy.,Istituto Auxologico Italiano, IRCCS, Laboratory of Cardiovascular Genetics, Milan, Italy.,Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart
| | - Najim Lahrouchi
- Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart.,Amsterdam UMC, University of Amsterdam, Heart Center; Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Naomasa Makita
- National Cerebral and Cardiovascular Center, Research Institute and Omics Research Center, Osaka, Japan
| | - Gabrielle Norrish
- Centre for Inherited Cardiovascular Diseases, Great Ormond Street Hospital, London, UK.,Institute of Cardiovascular Science, University College London, London, UK
| | - Hans H Odland
- Department of Pediatric Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Seiko Ohno
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan.,Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - John Papagiannis
- Division of Cardiology, Children's Mercy Hospital, Kansas City, MO, USA
| | - Gianfranco Parati
- Istituto Auxologico Italiano, IRCCS, Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy.,Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Nicole Sekarski
- Paediatric Cardiology Unit, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Kristian Tveten
- Department of Medical Genetics, Telemark Hospital Trust, Skien, Norway
| | - Matteo Vatta
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.,Invitae Corporation, San Francisco, CA, USA
| | - Gregory Webster
- Division of Cardiology, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Arthur A M Wilde
- Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart.,Amsterdam UMC, University of Amsterdam, Heart Center; Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Julianne Wojciak
- Department of Genomic Medicine, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Michael J Ackerman
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Peter J Schwartz
- Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Milan, Italy.,Istituto Auxologico Italiano, IRCCS, Laboratory of Cardiovascular Genetics, Milan, Italy.,Member of the European Reference Network for Rare, Low Prevalence and Complex Diseases of the Heart-ERN GUARD-Heart
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38
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Tsai WC, Guo S, Olaopa MA, Field LJ, Yang J, Shen C, Chang CP, Chen PS, Rubart M. Complex Arrhythmia Syndrome in a Knock-In Mouse Model Carrier of the N98S Calm1 Mutation. Circulation 2020; 142:1937-1955. [PMID: 32929985 DOI: 10.1161/circulationaha.120.046450] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Calmodulin mutations are associated with arrhythmia syndromes in humans. Exome sequencing previously identified a de novo mutation in CALM1 resulting in a p.N98S substitution in a patient with sinus bradycardia and stress-induced bidirectional ventricular ectopy. The objectives of the present study were to determine if mice carrying the N98S mutation knocked into Calm1 replicate the human arrhythmia phenotype and to examine arrhythmia mechanisms. METHODS Mouse lines heterozygous for the Calm1N98S allele (Calm1N98S/+) were generated using CRISPR/Cas9 technology. Adult mutant mice and their wildtype littermates (Calm1+/+) underwent electrocardiographic monitoring. Ventricular de- and repolarization was assessed in isolated hearts using optical voltage mapping. Action potentials and whole-cell currents and [Ca2+]i, as well, were measured in single ventricular myocytes using the patch-clamp technique and fluorescence microscopy, respectively. The microelectrode technique was used for in situ membrane voltage monitoring of ventricular conduction fibers. RESULTS Two biologically independent knock-in mouse lines heterozygous for the Calm1N98S allele were generated. Calm1N98S/+ mice of either sex and line exhibited sinus bradycardia, QTc interval prolongation, and catecholaminergic bidirectional ventricular tachycardia. Male mutant mice also showed QRS widening. Pharmacological blockade and activation of β-adrenergic receptors rescued and exacerbated, respectively, the long-QT phenotype of Calm1N98S/+ mice. Optical and electric assessment of membrane potential in isolated hearts and single left ventricular myocytes, respectively, revealed β-adrenergically induced delay of repolarization. β-Adrenergic stimulation increased peak density, slowed inactivation, and left-shifted the activation curve of ICa.L significantly more in Calm1N98S/+ versus Calm1+/+ ventricular myocytes, increasing late ICa.L in the former. Rapidly paced Calm1N98S/+ ventricular myocytes showed increased propensity to delayed afterdepolarization-induced triggered activity, whereas in situ His-Purkinje fibers exhibited increased susceptibility for pause-dependent early afterdepolarizations. Epicardial mapping of Calm1N98S/+ hearts showed that both reentry and focal mechanisms contribute to arrhythmogenesis. CONCLUSIONS Heterozygosity for the Calm1N98S mutation is causative of an arrhythmia syndrome characterized by sinus bradycardia, QRS widening, adrenergically mediated QTc interval prolongation, and bidirectional ventricular tachycardia. β-Adrenergically induced ICa.L dysregulation contributes to the long-QT phenotype. Pause-dependent early afterdepolarizations and tachycardia-induced delayed afterdepolarizations originating in the His-Purkinje network and ventricular myocytes, respectively, constitute potential sources of arrhythmia in Calm1N98S/+ hearts.
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Affiliation(s)
- Wen-Chin Tsai
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (W.-C.T., S.G., M.A.O., J.Y., C.-P.C. P.-S.C., M.R.), Indiana University School of Medicine, Indianapolis.,Department of Cardiology, Cardiovascular Research Center, Buddhist Tzu Chi General Hospital and Tzu Chi University, Hualien, Taiwan (W.-C.T.)
| | - Shuai Guo
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (W.-C.T., S.G., M.A.O., J.Y., C.-P.C. P.-S.C., M.R.), Indiana University School of Medicine, Indianapolis.,Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China (S.G.)
| | - Michael A Olaopa
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (W.-C.T., S.G., M.A.O., J.Y., C.-P.C. P.-S.C., M.R.), Indiana University School of Medicine, Indianapolis
| | - Loren J Field
- Wells Center for Pediatric Research, Department of Pediatrics (L.J.F., M.R.), Indiana University School of Medicine, Indianapolis
| | - Jin Yang
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (W.-C.T., S.G., M.A.O., J.Y., C.-P.C. P.-S.C., M.R.), Indiana University School of Medicine, Indianapolis
| | - Changyu Shen
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (C.S.)
| | - Ching-Pin Chang
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (W.-C.T., S.G., M.A.O., J.Y., C.-P.C. P.-S.C., M.R.), Indiana University School of Medicine, Indianapolis
| | - Peng-Sheng Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (W.-C.T., S.G., M.A.O., J.Y., C.-P.C. P.-S.C., M.R.), Indiana University School of Medicine, Indianapolis
| | - Michael Rubart
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (W.-C.T., S.G., M.A.O., J.Y., C.-P.C. P.-S.C., M.R.), Indiana University School of Medicine, Indianapolis.,Wells Center for Pediatric Research, Department of Pediatrics (L.J.F., M.R.), Indiana University School of Medicine, Indianapolis
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39
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Saljic A, Muthukumarasamy KM, la Cour JM, Boddum K, Grunnet M, Berchtold MW, Jespersen T. Impact of arrhythmogenic calmodulin variants on small conductance Ca 2+ -activated K + (SK3) channels. Physiol Rep 2020; 7:e14210. [PMID: 31587513 PMCID: PMC6778599 DOI: 10.14814/phy2.14210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023] Open
Abstract
Calmodulin (CaM) is a ubiquitous Ca2+‐sensing protein regulating many important cellular processes. Several CaM‐associated variants have been identified in a small group of patients with cardiac arrhythmias. The mechanism remains largely unknown, even though a number of ion channels, including the ryanodine receptors and the L‐type calcium channels have been shown to be functionally affected by the presence of mutant CaM. CaM is constitutively bound to the SK channel, which underlies the calcium‐gated ISK contributing to cardiac repolarization. The CaM binding to SK channels is essential for gating, correct assembly, and membrane expression. To elucidate the effect of nine different arrhythmogenic CaM variants on SK3 channel function, HEK293 cells stably expressing SK3 were transiently co‐transfected with CaMWT or variant and whole‐cell patch‐clamp recordings were performed with a calculated free Ca2+ concentration of 400 nmol/L. MDCK cells were transiently transfected with SK3 and/or CaMWT or variant to address SK3 and CaM localization by immunocytochemistry. The LQTS‐associated variants CaMD96V, CaMD130G, and CaMF142L reduced ISK,Ca compared with CaMWT (P < 0.01, P < 0.001, and P < 0.05, respectively). The CPVT associated variant CaMN54I also reduced the ISK,Ca (P < 0.05), which was linked to an accumulation of SK3/CaMN54I channel complexes in intracellular compartments (P < 0.05). The CPVT associated variants, CaMA103V and CaMD132E only revealed a tendency toward reduced current, while the variants CaMF90L and CaMN98S, causing LQTS syndrome, did not have any impact on ISK,Ca. In conclusion, we found that the arrhythmogenic CaM variants CaMN54I, CaMD96V, CaMD130G, and CaMF142L significantly down‐regulate the SK3 channel current, but with distinct mechanism.
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Affiliation(s)
- Arnela Saljic
- Laboratory of Cardiac Physiology, Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kalai Mangai Muthukumarasamy
- Laboratory of Cardiac Physiology, Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas Marstrand la Cour
- Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kim Boddum
- Laboratory of Cardiac Physiology, Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Martin Werner Berchtold
- Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Laboratory of Cardiac Physiology, Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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40
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Chakouri N, Diaz J, Yang PS, Ben-Johny M. Ca V channels reject signaling from a second CaM in eliciting Ca 2+-dependent feedback regulation. J Biol Chem 2020; 295:14948-14962. [PMID: 32820053 DOI: 10.1074/jbc.ra120.013777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 08/18/2020] [Indexed: 11/06/2022] Open
Abstract
Calmodulin (CaM) regulation of voltage-gated calcium (CaV1-2) channels is a powerful Ca2+-feedback mechanism to adjust channel activity in response to Ca2+ influx. Despite progress in resolving mechanisms of CaM-CaV feedback, the stoichiometry of CaM interaction with CaV channels remains ambiguous. Functional studies that tethered CaM to CaV1.2 suggested that a single CaM sufficed for Ca2+ feedback, yet biochemical, FRET, and structural studies showed that multiple CaM molecules interact with distinct interfaces within channel cytosolic segments, suggesting that functional Ca2+ regulation may be more nuanced. Resolving this ambiguity is critical as CaM is enriched in subcellular domains where CaV channels reside, such as the cardiac dyad. We here localized multiple CaMs to the CaV nanodomain by tethering either WT or mutant CaM that lack Ca2+-binding capacity to the pore-forming α-subunit of CaV1.2, CaV1.3, and CaV2.1 and/or the auxiliary β2A subunit. We observed that a single CaM tethered to either the α or β2A subunit tunes Ca2+ regulation of CaV channels. However, when multiple CaMs are localized concurrently, CaV channels preferentially respond to signaling from the α-subunit-tethered CaM. Mechanistically, the introduction of a second IQ domain to the CaV1.3 carboxyl tail switched the apparent functional stoichiometry, permitting two CaMs to mediate functional regulation. In all, Ca2+ feedback of CaV channels depends exquisitely on a single CaM preassociated with the α-subunit carboxyl tail. Additional CaMs that colocalize with the channel complex are unable to trigger Ca2+-dependent feedback of channel gating but may support alternate regulatory functions.
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Affiliation(s)
- Nourdine Chakouri
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York, USA
| | - Johanna Diaz
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York, USA
| | - Philemon S Yang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York, USA.
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Regulation of cardiovascular calcium channel activity by post-translational modifications or interacting proteins. Pflugers Arch 2020; 472:653-667. [PMID: 32435990 DOI: 10.1007/s00424-020-02398-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 02/08/2023]
Abstract
Voltage-gated calcium channels are the major pathway for Ca2+ influx to initiate the contraction of smooth and cardiac muscles. Alterations of calcium channel function have been implicated in multiple cardiovascular diseases, such as hypertension, atrial fibrillation, and long QT syndrome. Post-translational modifications do expand cardiovascular calcium channel structure and function to affect processes such as channel trafficking or polyubiquitination by two E3 ubiquitin ligases, Ret finger protein 2 (Rfp2) or murine double minute 2 protein (Mdm2). Additionally, biophysical property such as Ca2+-dependent inactivation (CDI) could be altered through binding of calmodulin, or channel activity could be modulated via S-nitrosylation by nitric oxide and phosphorylation by protein kinases or by interacting protein partners, such as galectin-1 and Rem. Understanding how cardiovascular calcium channel function is post-translationally remodeled under distinctive disease conditions will provide better information about calcium channel-related disease mechanisms and improve the development of more selective therapeutic agents for cardiovascular diseases.
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42
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Su J, Gao Q, Yu L, Sun X, Feng R, Shao D, Yuan Y, Zhu Z, Sun X, Kameyama M, Hao L. The LQT-associated calmodulin mutant E141G induces disturbed Ca 2+-dependent binding and a flickering gating mode of the Ca V1.2 channel. Am J Physiol Cell Physiol 2020; 318:C991-C1004. [PMID: 32186935 DOI: 10.1152/ajpcell.00019.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calmodulin (CaM) mutations are associated with congenital long QT (LQT) syndrome (LQTS), which may be related to the dysregulation of the cardiac-predominant Ca2+ channel isoform CaV1.2. Among various mutants, CaM-E141G was identified as a critical missense variant. However, the interaction of this CaM mutant with the CaV1.2 channel has not been determined. In this study, by utilizing a semiquantitative pull-down assay, we explored the interaction of CaM-E141G with CaM-binding peptide fragments of the CaV1.2 channel. Using the patch-clamp technique, we also investigated the electrophysiological effects of the mutant on CaV1.2 channel activity. We found that the maximum binding (Bmax) of CaM-E141G to the proximal COOH-terminal region, PreIQ-IQ, PreIQ, IQ, and NT (an NH2-terminal peptide) was decreased (by 17.71-59.26%) compared with that of wild-type CaM (CaM-WT). In particular, the Ca2+-dependent increase in Bmax became slower with the combination of CaM-E141G + PreIQ and IQ but faster in the case of NT. Functionally, CaM-WT and CaM-E141G at 500 nM Ca2+ decreased CaV1.2 channel activity to 24.88% and 55.99%, respectively, compared with 100 nM Ca2+, showing that the inhibitory effect was attenuated in CaM-E141G. The mean open time of the CaV1.2 channel was increased, and the number of blank traces with no channel opening was significantly decreased. Overall, CaM-E141G exhibits disrupted binding with the CaV1.2 channel and induces a flickering gating mode, which may result in the dysfunction of the CaV1.2 channel and, thus, the development of LQTS. The present study is the first to investigate the detailed binding properties and single-channel gating mode induced by the interaction of CaM-E141G with the CaV1.2 channel.
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Affiliation(s)
- Jingyang Su
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Qinghua Gao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China.,Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Lifeng Yu
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Xuanxuan Sun
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Rui Feng
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Dongxue Shao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Yuan Yuan
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Zhengnan Zhu
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Xuefei Sun
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Masaki Kameyama
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Liying Hao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
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43
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Wleklinski MJ, Kannankeril PJ, Knollmann BC. Molecular and tissue mechanisms of catecholaminergic polymorphic ventricular tachycardia. J Physiol 2020; 598:2817-2834. [PMID: 32115705 DOI: 10.1113/jp276757] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/03/2020] [Indexed: 12/21/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a stress-induced cardiac channelopathy that has a high mortality in untreated patients. Our understanding has grown tremendously since CPVT was first described as a clinical syndrome in 1995. It is now established that the deadly arrhythmias are caused by unregulated 'pathological' calcium release from the sarcoplasmic reticulum (SR), the major calcium storage organelle in striated muscle. Important questions remain regarding the molecular mechanisms that are responsible for the pathological calcium release, regarding the tissue origin of the arrhythmic beats that initiate ventricular tachycardia, and regarding optimal therapeutic approaches. At present, mutations in six genes involved in SR calcium release have been identified as the genetic cause of CPVT: RYR2 (encoding ryanodine receptor calcium release channel), CASQ2 (encoding cardiac calsequestrin), TRDN (encoding triadin), CALM1, CALM2 and CALM3 (encoding identical calmodulin protein). Here, we review each CPVT subtype and how CPVT mutations alter protein function, RyR2 calcium release channel regulation, and cellular calcium handling. We then discuss research and hypotheses surrounding the tissue mechanisms underlying CPVT, such as the pathophysiological role of sinus node dysfunction in CPVT, and whether the arrhythmogenic beats originate from the conduction system or the ventricular working myocardium. Finally, we review the treatments that are available for patients with CPVT, their efficacy, and how therapy could be improved in the future.
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Affiliation(s)
- Matthew J Wleklinski
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Prince J Kannankeril
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Bjӧrn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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44
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Holt C, Hamborg L, Lau K, Brohus M, Sørensen AB, Larsen KT, Sommer C, Van Petegem F, Overgaard MT, Wimmer R. The arrhythmogenic N53I variant subtly changes the structure and dynamics in the calmodulin N-terminal domain, altering its interaction with the cardiac ryanodine receptor. J Biol Chem 2020; 295:7620-7634. [PMID: 32317284 DOI: 10.1074/jbc.ra120.013430] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/18/2020] [Indexed: 12/11/2022] Open
Abstract
Mutations in the genes encoding the highly conserved Ca2+-sensing protein calmodulin (CaM) cause severe cardiac arrhythmias, including catecholaminergic polymorphic ventricular tachycardia or long QT syndrome and sudden cardiac death. Most of the identified arrhythmogenic mutations reside in the C-terminal domain of CaM and mostly affect Ca2+-coordinating residues. One exception is the catecholaminergic polymorphic ventricular tachycardia-causing N53I substitution, which resides in the N-terminal domain (N-domain). It does not affect Ca2+ coordination and has only a minor impact on binding affinity toward Ca2+ and on other biophysical properties. Nevertheless, the N53I substitution dramatically affects CaM's ability to reduce the open probability of the cardiac ryanodine receptor (RyR2) while having no effect on the regulation of the plasmalemmal voltage-gated Ca2+ channel, Cav1.2. To gain more insight into the molecular disease mechanism of this mutant, we used NMR to investigate the structures and dynamics of both apo- and Ca2+-bound CaM-N53I in solution. We also solved the crystal structures of WT and N53I CaM in complex with the primary calmodulin-binding domain (CaMBD2) from RyR2 at 1.84-2.13 Å resolutions. We found that all structures of the arrhythmogenic CaM-N53I variant are highly similar to those of WT CaM. However, we noted that the N53I substitution exposes an additional hydrophobic surface and that the intramolecular dynamics of the protein are significantly altered such that they destabilize the CaM N-domain. We conclude that the N53I-induced changes alter the interaction of the CaM N-domain with RyR2 and thereby likely cause the arrhythmogenic phenotype of this mutation.
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Affiliation(s)
- Christian Holt
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
| | - Louise Hamborg
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
| | - Kelvin Lau
- University of British Columbia, Department of Biochemistry and Molecular Biology, V6T 1Z3 Vancouver, British Columbia, Canada
| | - Malene Brohus
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
| | | | | | - Cordula Sommer
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
| | - Filip Van Petegem
- University of British Columbia, Department of Biochemistry and Molecular Biology, V6T 1Z3 Vancouver, British Columbia, Canada
| | | | - Reinhard Wimmer
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
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45
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Cardiomyocyte calcium handling in health and disease: Insights from in vitro and in silico studies. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 157:54-75. [PMID: 32188566 DOI: 10.1016/j.pbiomolbio.2020.02.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/31/2019] [Accepted: 02/29/2020] [Indexed: 02/07/2023]
Abstract
Calcium (Ca2+) plays a central role in cardiomyocyte excitation-contraction coupling. To ensure an optimal electrical impulse propagation and cardiac contraction, Ca2+ levels are regulated by a variety of Ca2+-handling proteins. In turn, Ca2+ modulates numerous electrophysiological processes. Accordingly, Ca2+-handling abnormalities can promote cardiac arrhythmias via various mechanisms, including the promotion of afterdepolarizations, ion-channel modulation and structural remodeling. In the last 30 years, significant improvements have been made in the computational modeling of cardiomyocyte Ca2+ handling under physiological and pathological conditions. However, numerous questions involving the Ca2+-dependent regulation of different macromolecular complexes, cross-talk between Ca2+-dependent regulatory pathways operating over a wide range of time scales, and bidirectional interactions between electrophysiology and mechanics remain to be addressed by in vitro and in silico studies. A better understanding of disease-specific Ca2+-dependent proarrhythmic mechanisms may facilitate the development of improved therapeutic strategies. In this review, we describe the fundamental mechanisms of cardiomyocyte Ca2+ handling in health and disease, and provide an overview of currently available computational models for cardiomyocyte Ca2+ handling. Finally, we discuss important uncertainties and open questions about cardiomyocyte Ca2+ handling and highlight how synergy between in vitro and in silico studies may help to answer several of these issues.
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46
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Kistamás K, Veress R, Horváth B, Bányász T, Nánási PP, Eisner DA. Calcium Handling Defects and Cardiac Arrhythmia Syndromes. Front Pharmacol 2020; 11:72. [PMID: 32161540 PMCID: PMC7052815 DOI: 10.3389/fphar.2020.00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Calcium ions (Ca2+) play a major role in the cardiac excitation-contraction coupling. Intracellular Ca2+ concentration increases during systole and falls in diastole thereby determining cardiac contraction and relaxation. Normal cardiac function also requires perfect organization of the ion currents at the cellular level to drive action potentials and to maintain action potential propagation and electrical homogeneity at the tissue level. Any imbalance in Ca2+ homeostasis of a cardiac myocyte can lead to electrical disturbances. This review aims to discuss cardiac physiology and pathophysiology from the elementary membrane processes that can cause the electrical instability of the ventricular myocytes through intracellular Ca2+ handling maladies to inherited and acquired arrhythmias. Finally, the paper will discuss the current therapeutic approaches targeting cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Roland Veress
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - David A Eisner
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
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47
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Calmodulin Mutations Associated with Heart Arrhythmia: A Status Report. Int J Mol Sci 2020; 21:ijms21041418. [PMID: 32093079 PMCID: PMC7073091 DOI: 10.3390/ijms21041418] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 02/06/2023] Open
Abstract
Calmodulin (CaM) is a ubiquitous intracellular Ca2+ sensing protein that modifies gating of numerous ion channels. CaM has an extraordinarily high level of evolutionary conservation, which led to the fundamental assumption that mutation would be lethal. However, in 2012, complete exome sequencing of infants suffering from recurrent cardiac arrest revealed de novo mutations in the three human CALM genes. The correlation between mutations and pathophysiology suggests defects in CaM-dependent ion channel functions. Here, we review the current state of the field for all reported CaM mutations associated with cardiac arrhythmias, including knowledge of their biochemical and structural characteristics, and progress towards understanding how these mutations affect cardiac ion channel function.
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48
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Wang K, Brohus M, Holt C, Overgaard MT, Wimmer R, Van Petegem F. Arrhythmia mutations in calmodulin can disrupt cooperativity of Ca 2+ binding and cause misfolding. J Physiol 2020; 598:1169-1186. [PMID: 32012279 DOI: 10.1113/jp279307] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/28/2020] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Mutations in the calmodulin protein (CaM) are associated with arrhythmia syndromes. This study focuses on understanding the structural characteristics of CaM disease mutants and their interactions with the voltage-gated calcium channel CaV 1.2. Arrhythmia mutations in CaM can lead to loss of Ca2+ binding, uncoupling of Ca2+ binding cooperativity, misfolding of the EF-hands and altered affinity for the calcium channel. These results help us to understand how different CaM mutants have distinct effects on structure and interactions with protein targets to cause disease. ABSTRACT Calmodulinopathies are life-threatening arrhythmia syndromes that arise from mutations in calmodulin (CaM), a calcium sensing protein whose sequence is completely conserved across all vertebrates. These mutations have been shown to interfere with the function of cardiac ion channels, including the voltage-gated Ca2+ channel CaV 1.2 and the ryanodine receptor (RyR2), in a mutation-specific manner. The ability of different CaM disease mutations to discriminate between these channels has been enigmatic. We present crystal structures of several C-terminal lobe mutants and an N-terminal lobe mutant in complex with the CaV 1.2 IQ domain, in conjunction with binding assays and complementary structural biology techniques. One mutation (D130G) causes a pathological conformation, with complete separation of EF-hands within the C-lobe and loss of Ca2+ binding in EF-hand 4. Another variant (Q136P) has severely reduced affinity for the IQ domain, and shows changes in the CD spectra under Ca2+ -saturating conditions when unbound to the IQ domain. Ca2+ binding to a pair of EF-hands normally proceeds with very high cooperativity, but we found that N98S CaM can adopt different conformations with either one or two Ca2+ ions bound to the C-lobe, possibly disrupting the cooperativity. An N-lobe variant (N54I), which causes severe stress-induced arrhythmia, does not show any major changes in complex with the IQ domain, providing a structural basis for why this mutant does not affect function of CaV 1.2. These findings show that different CaM mutants have distinct effects on both the CaM structure and interactions with protein targets, and act via distinct pathological mechanisms to cause disease.
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Affiliation(s)
- Kaiqian Wang
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, V6T 1Z3 Vancouver, BC, Canada
| | - Malene Brohus
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Christian Holt
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | | | - Reinhard Wimmer
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, V6T 1Z3 Vancouver, BC, Canada
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49
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Fleetwood O, Kasimova MA, Westerlund AM, Delemotte L. Molecular Insights from Conformational Ensembles via Machine Learning. Biophys J 2020; 118:765-780. [PMID: 31952811 PMCID: PMC7002924 DOI: 10.1016/j.bpj.2019.12.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/21/2019] [Accepted: 12/16/2019] [Indexed: 01/04/2023] Open
Abstract
Biomolecular simulations are intrinsically high dimensional and generate noisy data sets of ever-increasing size. Extracting important features from the data is crucial for understanding the biophysical properties of molecular processes, but remains a big challenge. Machine learning (ML) provides powerful dimensionality reduction tools. However, such methods are often criticized as resembling black boxes with limited human-interpretable insight. We use methods from supervised and unsupervised ML to efficiently create interpretable maps of important features from molecular simulations. We benchmark the performance of several methods, including neural networks, random forests, and principal component analysis, using a toy model with properties reminiscent of macromolecular behavior. We then analyze three diverse biological processes: conformational changes within the soluble protein calmodulin, ligand binding to a G protein-coupled receptor, and activation of an ion channel voltage-sensor domain, unraveling features critical for signal transduction, ligand binding, and voltage sensing. This work demonstrates the usefulness of ML in understanding biomolecular states and demystifying complex simulations.
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Affiliation(s)
- Oliver Fleetwood
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Marina A Kasimova
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Annie M Westerlund
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden.
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50
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Søndergaard MT, Liu Y, Guo W, Wei J, Wang R, Brohus M, Overgaard MT, Chen SRW. Role of cardiac ryanodine receptor calmodulin-binding domains in mediating the action of arrhythmogenic calmodulin N-domain mutation N54I. FEBS J 2019; 287:2256-2280. [PMID: 31763755 DOI: 10.1111/febs.15147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 09/12/2019] [Accepted: 11/19/2019] [Indexed: 11/27/2022]
Abstract
The Ca2+ -sensing protein calmodulin (CaM) inhibits cardiac ryanodine receptor (RyR2)-mediated Ca2+ release. CaM mutations associated with arrhythmias and sudden cardiac death have been shown to diminish CaM-dependent inhibition of RyR2, but the underlying mechanisms are not well understood. Nearly all arrhythmogenic CaM mutations identified are located in the C-domain of CaM and exert marked effects on Ca2+ binding to CaM and on the CaM C-domain interaction with the CaM-binding domain 2 (CaMBD2) in RyR2. Interestingly, the arrhythmogenic N-domain mutation CaM-N54I has little or no effect on Ca2+ binding to CaM or the CaM C-domain-RyR2 CaMBD2 interaction, unlike all CaM C-domain mutations. This suggests that CaM-N54I may diminish CaM-dependent RyR2 inhibition by affecting CaM N-domain interactions with RyR2 CaMBDs other than CaMBD2. To explore this possibility, we assessed the effects of deleting each of the four known CaMBDs in RyR2 (CaMBD1a, -1b, -2, or -3) on the CaM-dependent inhibition of RyR2-mediated Ca2+ release in HEK293 cells. We found that removing CaMBD1a, CaMBD1b, or CaMBD3 did not alter the effects of CaM-N54I or CaM-WT on RyR2 inhibition. On the other hand, deleting RyR2-CaMBD2 abolished the effects of both CaM-N54I and CaM-WT. Our results support that CaM-N54I causes aberrant RyR2 regulation via an uncharacterized CaMBD or less likely CaMBD2, and that RyR2 CaMBD2 is required for the actions of both N- and C-domain CaM mutations. Moreover, our results show that CaMBD1a is central to RyR2 regulation, but CaMBD1a, CaMBD1b, and CaMBD3 are not required for CaM-dependent inhibition of RyR2 in HEK293 cells.
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Affiliation(s)
- Mads T Søndergaard
- Department of Chemistry and Bioscience, Aalborg University, Denmark.,Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, Department of Biochemistry and Molecular Biology, University of Calgary, AB, Canada
| | - Yingjie Liu
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, Department of Biochemistry and Molecular Biology, University of Calgary, AB, Canada
| | - Wenting Guo
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, Department of Biochemistry and Molecular Biology, University of Calgary, AB, Canada
| | - Jinhong Wei
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, Department of Biochemistry and Molecular Biology, University of Calgary, AB, Canada
| | - Ruiwu Wang
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, Department of Biochemistry and Molecular Biology, University of Calgary, AB, Canada
| | - Malene Brohus
- Department of Chemistry and Bioscience, Aalborg University, Denmark
| | | | - S R Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, Department of Biochemistry and Molecular Biology, University of Calgary, AB, Canada
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