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Reilly-O'Donnell B, Robertson GB, Karumbi A, McIntyre C, Bal W, Nishi M, Takeshima H, Stewart AJ, Pitt SJ. Dysregulated Zn 2+ homeostasis impairs cardiac type-2 ryanodine receptor and mitsugumin 23 functions, leading to sarcoplasmic reticulum Ca 2+ leakage. J Biol Chem 2017. [PMID: 28630041 PMCID: PMC5555195 DOI: 10.1074/jbc.m117.781708] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Aberrant Zn2+ homeostasis is associated with dysregulated intracellular Ca2+ release, resulting in chronic heart failure. In the failing heart a small population of cardiac ryanodine receptors (RyR2) displays sub-conductance-state gating leading to Ca2+ leakage from sarcoplasmic reticulum (SR) stores, which impairs cardiac contractility. Previous evidence suggests contribution of RyR2-independent Ca2+ leakage through an uncharacterized mechanism. We sought to examine the role of Zn2+ in shaping intracellular Ca2+ release in cardiac muscle. Cardiac SR vesicles prepared from sheep or mouse ventricular tissue were incorporated into phospholipid bilayers under voltage-clamp conditions, and the direct action of Zn2+ on RyR2 channel function was examined. Under diastolic conditions, the addition of pathophysiological concentrations of Zn2+ (≥2 nm) caused dysregulated RyR2-channel openings. Our data also revealed that RyR2 channels are not the only SR Ca2+-permeable channels regulated by Zn2+. Elevating the cytosolic Zn2+ concentration to 1 nm increased the activity of the transmembrane protein mitsugumin 23 (MG23). The current amplitude of the MG23 full-open state was consistent with that previously reported for RyR2 sub-conductance gating, suggesting that in heart failure in which Zn2+ levels are elevated, RyR2 channels do not gate in a sub-conductance state, but rather MG23-gating becomes more apparent. We also show that in H9C2 cells exposed to ischemic conditions, intracellular Zn2+ levels are elevated, coinciding with increased MG23 expression. In conclusion, these data suggest that dysregulated Zn2+ homeostasis alters the function of both RyR2 and MG23 and that both ion channels play a key role in diastolic SR Ca2+ leakage.
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Affiliation(s)
- Benedict Reilly-O'Donnell
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Gavin B Robertson
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Angela Karumbi
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Connor McIntyre
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Wojciech Bal
- Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Science, Warsaw, 02-106 Poland, and
| | - Miyuki Nishi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Hiroshi Takeshima
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Alan J Stewart
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Samantha J Pitt
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom,
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2
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Norris NC, Joseph S, Aditya S, Karunasekara Y, Board PG, Dulhunty AF, Oakley AJ, Casarotto MG. Structural and biophysical analyses of the skeletal dihydropyridine receptor β subunit β 1a reveal critical roles of domain interactions for stability. J Biol Chem 2017; 292:8401-8411. [PMID: 28351836 DOI: 10.1074/jbc.m116.763896] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 03/16/2017] [Indexed: 01/02/2023] Open
Abstract
Excitation-contraction (EC) coupling in skeletal muscle requires a physical interaction between the voltage-gated calcium channel dihydropyridine receptor (DHPR) and the ryanodine receptor Ca2+ release channel. Although the exact molecular mechanism that initiates skeletal EC coupling is unresolved, it is clear that both the α1 and β subunits of DHPR are essential for this process. Here, we employed a series of techniques, including size-exclusion chromatography-multi-angle light scattering, differential scanning fluorimetry, and isothermal calorimetry, to characterize various biophysical properties of the skeletal DHPR β subunit β1a Removal of the intrinsically disordered N and C termini and the hook region of β1a prevented oligomerization, allowing for its structural determination by X-ray crystallography. The structure had a topology similar to that of previously determined β isoforms, which consist of SH3 and guanylate kinase domains. However, transition melting temperatures derived from the differential scanning fluorimetry experiments indicated a significant difference in stability of ∼2-3 °C between the β1a and β2a constructs, and the addition of the DHPR α1s I-II loop (α-interaction domain) peptide stabilized both β isoforms by ∼6-8 °C. Similar to other β isoforms, β1a bound with nanomolar affinity to the α-interaction domain, but binding affinities were influenced by amino acid substitutions in the adjacent SH3 domain. These results suggest that intramolecular interactions between the SH3 and guanylate kinase domains play a role in the stability of β1a while also providing a conduit for allosteric signaling events.
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Affiliation(s)
- Nicole C Norris
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Soumya Joseph
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Shouvik Aditya
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Yamuna Karunasekara
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Philip G Board
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Angela F Dulhunty
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Aaron J Oakley
- Department of Chemistry, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Marco G Casarotto
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia.
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3
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Li J, Wang R, Gannon OJ, Rezey AC, Jiang S, Gerlach BD, Liao G, Tang DD. Polo-like Kinase 1 Regulates Vimentin Phosphorylation at Ser-56 and Contraction in Smooth Muscle. J Biol Chem 2016; 291:23693-23703. [PMID: 27662907 PMCID: PMC5095422 DOI: 10.1074/jbc.m116.749341] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/15/2016] [Indexed: 11/06/2022] Open
Abstract
Polo-like kinase 1 (Plk1) is a serine/threonine-protein kinase that has been implicated in mitosis, cytokinesis, and smooth muscle cell proliferation. The role of Plk1 in smooth muscle contraction has not been investigated. Here, stimulation with acetylcholine induced Plk1 phosphorylation at Thr-210 (an indication of Plk1 activation) in smooth muscle. Contractile stimulation also activated Plk1 in live smooth muscle cells as evidenced by changes in fluorescence resonance energy transfer signal of a Plk1 sensor. Moreover, knockdown of Plk1 in smooth muscle attenuated force development. Smooth muscle conditional knock-out of Plk1 also diminished contraction of mouse tracheal rings. Plk1 knockdown inhibited acetylcholine-induced vimentin phosphorylation at Ser-56 without affecting myosin light chain phosphorylation. Expression of T210A Plk1 inhibited the agonist-induced vimentin phosphorylation at Ser-56 and contraction in smooth muscle. However, myosin light chain phosphorylation was not affected by T210A Plk1. Ste20-like kinase (SLK) is a serine/threonine-protein kinase that has been implicated in spindle orientation and microtubule organization during mitosis. In this study knockdown of SLK inhibited Plk1 phosphorylation at Thr-210 and activation. Finally, asthma is characterized by airway hyperresponsiveness, which largely stems from airway smooth muscle hyperreactivity. Here, smooth muscle conditional knock-out of Plk1 attenuated airway resistance and airway smooth muscle hyperreactivity in a murine model of asthma. Taken together, these findings suggest that Plk1 regulates smooth muscle contraction by modulating vimentin phosphorylation at Ser-56. Plk1 activation is regulated by SLK during contractile activation. Plk1 contributes to the pathogenesis of asthma.
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Affiliation(s)
- Jia Li
- From the Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York 12208
| | - Ruping Wang
- From the Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York 12208
| | - Olivia J Gannon
- From the Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York 12208
| | - Alyssa C Rezey
- From the Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York 12208
| | - Sixin Jiang
- From the Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York 12208
| | - Brennan D Gerlach
- From the Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York 12208
| | - Guoning Liao
- From the Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York 12208
| | - Dale D Tang
- From the Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York 12208
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4
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Habeck M, Tokhtaeva E, Nadav Y, Ben Zeev E, Ferris SP, Kaufman RJ, Bab-Dinitz E, Kaplan JH, Dada LA, Farfel Z, Tal DM, Katz A, Sachs G, Vagin O, Karlish SJD. Selective Assembly of Na,K-ATPase α2β2 Heterodimers in the Heart: DISTINCT FUNCTIONAL PROPERTIES AND ISOFORM-SELECTIVE INHIBITORS. J Biol Chem 2016; 291:23159-23174. [PMID: 27624940 DOI: 10.1074/jbc.m116.751735] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Indexed: 12/31/2022] Open
Abstract
The Na,K-ATPase α2 subunit plays a key role in cardiac muscle contraction by regulating intracellular Ca2+, whereas α1 has a more conventional role of maintaining ion homeostasis. The β subunit differentially regulates maturation, trafficking, and activity of α-β heterodimers. It is not known whether the distinct role of α2 in the heart is related to selective assembly with a particular one of the three β isoforms. We show here by immunofluorescence and co-immunoprecipitation that α2 is preferentially expressed with β2 in T-tubules of cardiac myocytes, forming α2β2 heterodimers. We have expressed human α1β1, α2β1, α2β2, and α2β3 in Pichia pastoris, purified the complexes, and compared their functional properties. α2β2 and α2β3 differ significantly from both α2β1 and α1β1 in having a higher K0.5K+ and lower K0.5Na+ for activating Na,K-ATPase. These features are the result of a large reduction in binding affinity for extracellular K+ and shift of the E1P-E2P conformational equilibrium toward E1P. A screen of perhydro-1,4-oxazepine derivatives of digoxin identified several derivatives (e.g. cyclobutyl) with strongly increased selectivity for inhibition of α2β2 and α2β3 over α1β1 (range 22-33-fold). Molecular modeling suggests a possible basis for isoform selectivity. The preferential assembly, specific T-tubular localization, and low K+ affinity of α2β2 could allow an acute response to raised ambient K+ concentrations in physiological conditions and explain the importance of α2β2 for cardiac muscle contractility. The high sensitivity of α2β2 to digoxin derivatives explains beneficial effects of cardiac glycosides for treatment of heart failure and potential of α2β2-selective digoxin derivatives for reducing cardiotoxicity.
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Affiliation(s)
| | - Elmira Tokhtaeva
- the Department of Physiology, School of Medicine, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Yotam Nadav
- From the Department of Biomolecular Sciences and
| | - Efrat Ben Zeev
- Israel National Centre for Personalized Medicine, Weizmann Institute of Science, Rehovoth 7610001, Israel
| | - Sean P Ferris
- the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | - Randal J Kaufman
- the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | | | - Jack H Kaplan
- the Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago, Illinois 60607, and
| | - Laura A Dada
- the Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Zvi Farfel
- From the Department of Biomolecular Sciences and.,the School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Daniel M Tal
- From the Department of Biomolecular Sciences and
| | - Adriana Katz
- From the Department of Biomolecular Sciences and
| | - George Sachs
- the Department of Physiology, School of Medicine, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Olga Vagin
- the Department of Physiology, School of Medicine, UCLA and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073,
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5
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Ávila-Medina J, Calderón-Sánchez E, González-Rodríguez P, Monje-Quiroga F, Rosado JA, Castellano A, Ordóñez A, Smani T. Orai1 and TRPC1 Proteins Co-localize with CaV1.2 Channels to Form a Signal Complex in Vascular Smooth Muscle Cells. J Biol Chem 2016; 291:21148-21159. [PMID: 27535226 DOI: 10.1074/jbc.m116.742171] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Indexed: 11/06/2022] Open
Abstract
Voltage-dependent CaV1.2 L-type Ca2+ channels (LTCC) are the main route for calcium entry in vascular smooth muscle cells (VSMC). Several studies have also determined the relevant role of store-operated Ca2+ channels (SOCC) in vascular tone regulation. Nevertheless, the role of Orai1- and TRPC1-dependent SOCC in vascular tone regulation and their possible interaction with CaV1.2 are still unknown. The current study sought to characterize the co-activation of SOCC and LTCC upon stimulation by agonists, and to determine the possible crosstalk between Orai1, TRPC1, and CaV1.2. Aorta rings and isolated VSMC obtained from wild type or smooth muscle-selective conditional CaV1.2 knock-out (CaV1.2KO) mice were used to study vascular contractility, intracellular Ca2+ mobilization, and distribution of ion channels. We found that serotonin (5-HT) or store depletion with thapsigargin (TG) enhanced intracellular free Ca2+ concentration ([Ca2+]i) and stimulated aorta contraction. These responses were sensitive to LTCC and SOCC inhibitors. Also, 5-HT- and TG-induced responses were significantly attenuated in CaV1.2KO mice. Furthermore, hyperpolarization induced with cromakalim or valinomycin significantly reduced both 5-HT and TG responses, whereas these responses were enhanced with LTCC agonist Bay-K-8644. Interestingly, in situ proximity ligation assay revealed that CaV1.2 interacts with Orai1 and TRPC1 in untreated VSMC. These interactions enhanced significantly after stimulation of cells with 5-HT and TG. Therefore, these data indicate for the first time a functional interaction between Orai1, TRPC1, and CaV1.2 channels in VSMC, confirming that upon agonist stimulation, vessel contraction involves Ca2+ entry due to co-activation of Orai1- and TRPC1-dependent SOCC and LTCC.
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Affiliation(s)
- Javier Ávila-Medina
- From the Departamento de Fisiología Médica y Biofísica and Groupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | - Eva Calderón-Sánchez
- Groupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | | | - Francisco Monje-Quiroga
- the Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Wien, Austria, and
| | - Juan Antonio Rosado
- the Departamento de Fisiología, Universidad de Extremadura, 10071 Cáceres, Spain
| | | | - Antonio Ordóñez
- Groupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | - Tarik Smani
- From the Departamento de Fisiología Médica y Biofísica and Groupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain,
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6
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Mosca B, Eckhardt J, Bergamelli L, Treves S, Bongianino R, De Negri M, Priori SG, Protasi F, Zorzato F. Role of the JP45-Calsequestrin Complex on Calcium Entry in Slow Twitch Skeletal Muscles. J Biol Chem 2016; 291:14555-65. [PMID: 27189940 PMCID: PMC4938177 DOI: 10.1074/jbc.m115.709071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Indexed: 12/27/2022] Open
Abstract
We exploited a variety of mouse models to assess the roles of JP45-CASQ1 (CASQ, calsequestrin) and JP45-CASQ2 on calcium entry in slow twitch muscles. In flexor digitorum brevis (FDB) fibers isolated from JP45-CASQ1-CASQ2 triple KO mice, calcium transients induced by tetanic stimulation rely on calcium entry via La3+- and nifedipine-sensitive calcium channels. The comparison of excitation-coupled calcium entry (ECCE) between FDB fibers from WT, JP45KO, CASQ1KO, CASQ2KO, JP45-CASQ1 double KO, JP45-CASQ2 double KO, and JP45-CASQ1-CASQ2 triple KO shows that ECCE enhancement requires ablation of both CASQs and JP45. Calcium entry activated by ablation of both JP45-CASQ1 and JP45-CASQ2 complexes supports tetanic force development in slow twitch soleus muscles. In addition, we show that CASQs interact with JP45 at Ca2+ concentrations similar to those present in the lumen of the sarcoplasmic reticulum at rest, whereas Ca2+ concentrations similar to those present in the SR lumen after depolarization-induced calcium release cause the dissociation of JP45 from CASQs. Our results show that the complex JP45-CASQs is a negative regulator of ECCE and that tetanic force development in slow twitch muscles is supported by the dynamic interaction between JP45 and CASQs.
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Affiliation(s)
- Barbara Mosca
- Department of Life Science and Biotechnology, University of Ferrara, Via Borsari 46, 44100, Ferrara, Italy
| | - Jan Eckhardt
- From the Departments of Anaesthesia and Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Leda Bergamelli
- Department of Life Science and Biotechnology, University of Ferrara, Via Borsari 46, 44100, Ferrara, Italy
| | - Susan Treves
- Department of Life Science and Biotechnology, University of Ferrara, Via Borsari 46, 44100, Ferrara, Italy From the Departments of Anaesthesia and Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Rossana Bongianino
- Molecular Cardiology Laboratories Fondazione Salvatore Maugeri, Via Maugeri 10/10°, 27100, Pavia Italy
| | - Marco De Negri
- Molecular Cardiology Laboratories Fondazione Salvatore Maugeri, Via Maugeri 10/10°, 27100, Pavia Italy
| | - Silvia G Priori
- Molecular Cardiology Laboratories Fondazione Salvatore Maugeri, Via Maugeri 10/10°, 27100, Pavia Italy, Department of Molecular Medicine, University of Pavia, Pavia Italy, and
| | - Feliciano Protasi
- Center for Research on Ageing and Translational Medicine and DNICS (Department of Neuroscience, Imaging, and Clinical Sciences), University G. d'Annunzio, 66100 Chieti, Italy
| | - Francesco Zorzato
- From the Departments of Anaesthesia and Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland, Department of Life Science and Biotechnology, University of Ferrara, Via Borsari 46, 44100, Ferrara, Italy
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7
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Mahalingam M, Perez CF, Fessenden JD. Fluorescence Resonance Energy Transfer-based Structural Analysis of the Dihydropyridine Receptor α1S Subunit Reveals Conformational Differences Induced by Binding of the β1a Subunit. J Biol Chem 2016; 291:13762-70. [PMID: 27129199 DOI: 10.1074/jbc.m115.704049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Indexed: 11/06/2022] Open
Abstract
The skeletal muscle dihydropyridine receptor α1S subunit plays a key role in skeletal muscle excitation-contraction coupling by sensing membrane voltage changes and then triggering intracellular calcium release. The cytoplasmic loops connecting four homologous α1S structural domains have diverse functions, but their structural arrangement is poorly understood. Here, we used a novel FRET-based method to characterize the relative proximity of these intracellular loops in α1S subunits expressed in intact cells. In dysgenic myotubes, energy transfer was observed from an N-terminal-fused YFP to a FRET acceptor, ReAsH (resorufin arsenical hairpin binder), targeted to each α1S intracellular loop, with the highest FRET efficiencies measured to the α1S II-III loop and C-terminal tail. However, in HEK-293T cells, FRET efficiencies from the α1S N terminus to the II-III and III-IV loops and the C-terminal tail were significantly lower, thus suggesting that these loop structures are influenced by the cellular microenvironment. The addition of the β1a dihydropyridine receptor subunit enhanced FRET to the II-III loop, thus indicating that β1a binding directly affects II-III loop conformation. This specific structural change required the C-terminal 36 amino acids of β1a, which are essential to support EC coupling. Direct FRET measurements between α1S and β1a confirmed that both wild type and truncated β1a bind similarly to α1S These results provide new insights into the role of muscle-specific proteins on the structural arrangement of α1S intracellular loops and point to a new conformational effect of the β1a subunit in supporting skeletal muscle excitation-contraction coupling.
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Affiliation(s)
- Mohana Mahalingam
- From the Department of Anesthesia, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115
| | - Claudio F Perez
- From the Department of Anesthesia, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115
| | - James D Fessenden
- From the Department of Anesthesia, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115
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8
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Guo W, Sun B, Xiao Z, Liu Y, Wang Y, Zhang L, Wang R, Chen SRW. The EF-hand Ca2+ Binding Domain Is Not Required for Cytosolic Ca2+ Activation of the Cardiac Ryanodine Receptor. J Biol Chem 2015; 291:2150-60. [PMID: 26663082 DOI: 10.1074/jbc.m115.693325] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Indexed: 11/06/2022] Open
Abstract
Activation of the cardiac ryanodine receptor (RyR2) by elevating cytosolic Ca(2+) is a central step in the process of Ca(2+)-induced Ca(2+) release, but the molecular basis of RyR2 activation by cytosolic Ca(2+) is poorly defined. It has been proposed recently that the putative Ca(2+) binding domain encompassing a pair of EF-hand motifs (EF1 and EF2) in the skeletal muscle ryanodine receptor (RyR1) functions as a Ca(2+) sensor that regulates the gating of RyR1. Although the role of the EF-hand domain in RyR1 function has been studied extensively, little is known about the functional significance of the corresponding EF-hand domain in RyR2. Here we investigate the effect of mutations in the EF-hand motifs on the Ca(2+) activation of RyR2. We found that mutations in the EF-hand motifs or deletion of the entire EF-hand domain did not affect the Ca(2+)-dependent activation of [(3)H]ryanodine binding or the cytosolic Ca(2+) activation of RyR2. On the other hand, deletion of the EF-hand domain markedly suppressed the luminal Ca(2+) activation of RyR2 and spontaneous Ca(2+) release in HEK293 cells during store Ca(2+) overload or store overload-induced Ca(2+) release (SOICR). Furthermore, mutations in the EF2 motif, but not EF1 motif, of RyR2 raised the threshold for SOICR termination, whereas deletion of the EF-hand domain of RyR2 increased both the activation and termination thresholds for SOICR. These results indicate that, although the EF-hand domain is not required for RyR2 activation by cytosolic Ca(2+), it plays an important role in luminal Ca(2+) activation and SOICR.
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Affiliation(s)
- Wenting Guo
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Bo Sun
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Zhichao Xiao
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Yingjie Liu
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Yundi Wang
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Lin Zhang
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ruiwu Wang
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - S R Wayne Chen
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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9
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Søndergaard MT, Tian X, Liu Y, Wang R, Chazin WJ, Chen SRW, Overgaard MT. Arrhythmogenic Calmodulin Mutations Affect the Activation and Termination of Cardiac Ryanodine Receptor-mediated Ca2+ Release. J Biol Chem 2015; 290:26151-62. [PMID: 26309258 DOI: 10.1074/jbc.m115.676627] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Indexed: 11/06/2022] Open
Abstract
The intracellular Ca(2+) sensor calmodulin (CaM) regulates the cardiac Ca(2+) release channel/ryanodine receptor 2 (RyR2), and mutations in CaM cause arrhythmias such as catecholaminergic polymorphic ventricular tachycardia (CPVT) and long QT syndrome. Here, we investigated the effect of CaM mutations causing CPVT (N53I), long QT syndrome (D95V and D129G), or both (CaM N97S) on RyR2-mediated Ca(2+) release. All mutations increased Ca(2+) release and rendered RyR2 more susceptible to store overload-induced Ca(2+) release (SOICR) by lowering the threshold of store Ca(2+) content at which SOICR occurred and the threshold at which SOICR terminated. To obtain mechanistic insights, we investigated the Ca(2+) binding of the N- and C-terminal domains (N- and C-domain) of CaM in the presence of a peptide corresponding to the CaM-binding domain of RyR2. The N53I mutation decreased the affinity of Ca(2+) binding to the N-domain of CaM, relative to CaM WT, but did not affect the C-domain. Conversely, mutations N97S, D95V, and D129G had little or no effect on Ca(2+) binding to the N-domain but markedly decreased the affinity of the C-domain for Ca(2+). These results suggest that mutations D95V, N97S, and D129G alter the interaction between CaM and the CaMBD and thus RyR2 regulation. Because the N53I mutation minimally affected Ca(2+) binding to the C-domain, it must cause aberrant regulation via a different mechanism. These results support aberrant RyR2 regulation as the disease mechanism for CPVT associated with CaM mutations and shows that CaM mutations not associated with CPVT can also affect RyR2. A model for the CaM-RyR2 interaction, where the Ca(2+)-saturated C-domain is constitutively bound to RyR2 and the N-domain senses increases in Ca(2+) concentration, is proposed.
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Affiliation(s)
- Mads T Søndergaard
- From the Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark, the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Xixi Tian
- the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Yingjie Liu
- the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Ruiwu Wang
- the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Walter J Chazin
- the Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - S R Wayne Chen
- the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Michael T Overgaard
- From the Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark,
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10
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Hiess F, Vallmitjana A, Wang R, Cheng H, ter Keurs HEDJ, Chen J, Hove-Madsen L, Benitez R, Chen SRW. Distribution and Function of Cardiac Ryanodine Receptor Clusters in Live Ventricular Myocytes. J Biol Chem 2015; 290:20477-87. [PMID: 26109063 DOI: 10.1074/jbc.m115.650531] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Indexed: 11/06/2022] Open
Abstract
The cardiac Ca(2+) release channel (ryanodine receptor, RyR2) plays an essential role in excitation-contraction coupling in cardiac muscle cells. Effective and stable excitation-contraction coupling critically depends not only on the expression of RyR2, but also on its distribution. Despite its importance, little is known about the distribution and organization of RyR2 in living cells. To study the distribution of RyR2 in living cardiomyocytes, we generated a knock-in mouse model expressing a GFP-tagged RyR2 (GFP-RyR2). Confocal imaging of live ventricular myocytes isolated from the GFP-RyR2 mouse heart revealed clusters of GFP-RyR2 organized in rows with a striated pattern. Similar organization of GFP-RyR2 clusters was observed in fixed ventricular myocytes. Immunofluorescence staining with the anti-α-actinin antibody (a z-line marker) showed that nearly all GFP-RyR2 clusters were localized in the z-line zone. There were small regions with dislocated GFP-RyR2 clusters. Interestingly, these same regions also displayed dislocated z-lines. Staining with di-8-ANEPPS revealed that nearly all GFP-RyR2 clusters were co-localized with transverse but not longitudinal tubules, whereas staining with MitoTracker Red showed that GFP-RyR2 clusters were not co-localized with mitochondria in live ventricular myocytes. We also found GFP-RyR2 clusters interspersed between z-lines only at the periphery of live ventricular myocytes. Simultaneous detection of GFP-RyR2 clusters and Ca(2+) sparks showed that Ca(2+) sparks originated exclusively from RyR2 clusters. Ca(2+) sparks from RyR2 clusters induced no detectable changes in mitochondrial Ca(2+) level. These results reveal, for the first time, the distribution of RyR2 clusters and its functional correlation in living ventricular myocytes.
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Affiliation(s)
- Florian Hiess
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and
| | - Alexander Vallmitjana
- the Department of Automatic Control, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
| | - Ruiwu Wang
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and
| | - Hongqiang Cheng
- the Department of Medicine, University of California at San Diego, La Jolla, California 92161, and
| | - Henk E D J ter Keurs
- the Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Ju Chen
- the Department of Medicine, University of California at San Diego, La Jolla, California 92161, and
| | - Leif Hove-Madsen
- the Cardiovascular Research Centre CSIC-ICCC, Hospital de Sant Pau, 08025 Barcelona, Spain
| | - Raul Benitez
- the Department of Automatic Control, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
| | - S R Wayne Chen
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and
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11
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Guo A, Hall D, Zhang C, Peng T, Miller JD, Kutschke W, Grueter CE, Johnson FL, Lin RZ, Song LS. Molecular Determinants of Calpain-dependent Cleavage of Junctophilin-2 Protein in Cardiomyocytes. J Biol Chem 2015; 290:17946-17955. [PMID: 26063807 DOI: 10.1074/jbc.m115.652396] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Indexed: 12/29/2022] Open
Abstract
Junctophilin-2 (JP2), a membrane-binding protein that provides a structural bridge between the plasmalemma and sarcoplasmic reticulum, is essential for precise Ca(2+)-induced Ca(2+) release during excitation-contraction coupling in cardiomyocytes. In animal and human failing hearts, expression of JP2 is decreased markedly, but the molecular mechanisms underlying JP2 down-regulation remain incompletely defined. In mouse hearts, ischemia/reperfusion injury resulted in acute JP2 down-regulation, which was attenuated by pretreatment with the calpain inhibitor MDL-28170 or by transgenic overexpression of calpastatin, an endogenous calpain inhibitor. Using a combination of computational analysis to predict calpain cleavage sites and in vitro calpain proteolysis reactions, we identified four putative calpain cleavage sites within JP2 with three N-terminal and one C-terminal cleavage sites. Mutagenesis defined the C-terminal region of JP2 as the predominant calpain cleavage site. Exogenous expression of putative JP2 cleavage fragments was not sufficient to rescue Ca(2+) handling in JP2-deficient cardiomyocytes, indicating that cleaved JP2 is non-functional for normal Ca(2+)-induced Ca(2+) release. These data provide new molecular insights into the posttranslational regulatory mechanisms of JP2 in cardiac diseases.
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Affiliation(s)
- Ang Guo
- Division of Cardiovascular Medicine, Department of Internal Medicine and François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Duane Hall
- Division of Cardiovascular Medicine, Department of Internal Medicine and François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Caimei Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine and François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Tianqing Peng
- Departments of Medicine and Pathology, University of Western Ontario, London, Ontario N6A 4G5, Canada
| | - Jordan D Miller
- Division of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota 55905
| | - William Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine and François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Chad E Grueter
- Division of Cardiovascular Medicine, Department of Internal Medicine and François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Frances L Johnson
- Division of Cardiovascular Medicine, Department of Internal Medicine and François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Richard Z Lin
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York 11794
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine and François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242.
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12
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Abstract
Aberrant Zn2+ homeostasis is a hallmark of certain cardiomyopathies associated with altered contractile force. In this study, we addressed whether Zn2+ modulates cardiac ryanodine receptor gating and Ca2+ dynamics in isolated cardiomyocytes. We reveal that Zn2+ is a high affinity regulator of RyR2 displaying three modes of operation. Picomolar free Zn2+ concentrations potentiate RyR2 responses, but channel activation is still dependent on the presence of cytosolic Ca2+. At concentrations of free Zn2+ >1 nm, Zn2+ is the main activating ligand, and the dependence on Ca2+ is removed. Zn2+ is therefore a higher affinity activator of RyR2 than Ca2+. Millimolar levels of free Zn2+ were found to inhibit channel openings. In cardiomyocytes, consistent with our single channel results, we show that Zn2+ modulates both the frequency and amplitude of Ca2+ waves in a concentration-dependent manner and that physiological levels of Zn2+ elicit Ca2+ release in the absence of activating levels of cytosolic Ca2+. This highlights a new role for intracellular Zn2+ in shaping Ca2+ dynamics in cardiomyocytes through modulation of RyR2 gating.
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Affiliation(s)
- Jason Woodier
- From the School of Medicine, University of St. Andrews, St. Andrews KY16 9TF, United Kingdom and
| | - Richard D Rainbow
- the Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield General Hospital, Leicester LE3 9QP, United Kingdom
| | - Alan J Stewart
- From the School of Medicine, University of St. Andrews, St. Andrews KY16 9TF, United Kingdom and
| | - Samantha J Pitt
- From the School of Medicine, University of St. Andrews, St. Andrews KY16 9TF, United Kingdom and
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