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Dong J, Li D, Kang L, Luo C, Wang J. Insights into human eNOS, nNOS and iNOS structures and medicinal indications from statistical analyses of their interactions with bound compounds. BIOPHYSICS REPORTS 2023; 9:159-175. [PMID: 38028152 PMCID: PMC10648232 DOI: 10.52601/bpr.2023.210045] [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: 10/25/2021] [Accepted: 05/18/2023] [Indexed: 12/01/2023] Open
Abstract
83 Structures of human nNOS, 55 structures of human eNOS, 13 structures of iNOS, and about 126 reported NOS-bound compounds are summarized and analyzed. Structural and statistical analysis show that, at least one copy of each analyzed compound binds to the active site (the substrate arginine binding site) of human NOS. And binding features of the three isoforms show differences, but the binding preference of compounds is not in the way helpful for inhibitor design targeting nNOS and iNOS, or for activator design targeting eNOS. This research shows that there is a strong structural and functional similarity between oxygenase domains of human NOS isoforms, especially the architecture, residue composition, size, shape, and distribution profile of hydrophobicity, polarity and charge of the active site. The selectivity and efficacy of inhibitors over the rest of isoforms rely a lot on chance and randomness. Further increase of selectivity via rational improvement is uncertain, unpredictable and unreliable, therefore, to achieve high selectivity through targeting this site is complicated and requires combinative investigation. After analysis on the current two targeting sites in NOS, the highly conserved arginine binding pocket and H4B binding pocket, new potential drug-targeting sites are proposed based on structure and sequence profiling. This comprehensive analysis on the structure and interaction profiles of human NOS and bound compounds provides fresh insights for drug discovery and pharmacological research, and the new discovery here is practically applied to guide protein-structure based drug discovery.
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Affiliation(s)
- Jianshu Dong
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Henan Province, Zhengzhou University, Zhengzhou 450001, China
- Key Laboratory of Henan Province for Drug Quality control and Evaluation, Zhengzhou University, Zhengzhou 450001, China
| | - Dié Li
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Henan Province, Zhengzhou University, Zhengzhou 450001, China
- Key Laboratory of Henan Province for Drug Quality control and Evaluation, Zhengzhou University, Zhengzhou 450001, China
| | - Lei Kang
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Henan Province, Zhengzhou University, Zhengzhou 450001, China
- Key Laboratory of Henan Province for Drug Quality control and Evaluation, Zhengzhou University, Zhengzhou 450001, China
| | - Chenbing Luo
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China
- Institute of Drug Discovery and Development, Zhengzhou University, Zhengzhou 450001, China
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Zhengzhou University, Zhengzhou 450001, China
- Collaborative Innovation Center of New Drug Research and Safety Evaluation, Henan Province, Zhengzhou University, Zhengzhou 450001, China
- Key Laboratory of Henan Province for Drug Quality control and Evaluation, Zhengzhou University, Zhengzhou 450001, China
| | - Jiangyun Wang
- Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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2
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Lansdell TA, Chambers LC, Dorrance AM. Endothelial Cells and the Cerebral Circulation. Compr Physiol 2022; 12:3449-3508. [PMID: 35766836 DOI: 10.1002/cphy.c210015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Endothelial cells form the innermost layer of all blood vessels and are the only vascular component that remains throughout all vascular segments. The cerebral vasculature has several unique properties not found in the peripheral circulation; this requires that the cerebral endothelium be considered as a unique entity. Cerebral endothelial cells perform several functions vital for brain health. The cerebral vasculature is responsible for protecting the brain from external threats carried in the blood. The endothelial cells are central to this requirement as they form the basis of the blood-brain barrier. The endothelium also regulates fibrinolysis, thrombosis, platelet activation, vascular permeability, metabolism, catabolism, inflammation, and white cell trafficking. Endothelial cells regulate the changes in vascular structure caused by angiogenesis and artery remodeling. Further, the endothelium contributes to vascular tone, allowing proper perfusion of the brain which has high energy demands and no energy stores. In this article, we discuss the basic anatomy and physiology of the cerebral endothelium. Where appropriate, we discuss the detrimental effects of high blood pressure on the cerebral endothelium and the contribution of cerebrovascular disease endothelial dysfunction and dementia. © 2022 American Physiological Society. Compr Physiol 12:3449-3508, 2022.
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Affiliation(s)
- Theresa A Lansdell
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Laura C Chambers
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
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3
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A Free-Energy Landscape Analysis of Calmodulin Obtained from an NMR Data-Utilized Multi-Scale Divide-and-Conquer Molecular Dynamics Simulation. Life (Basel) 2021; 11:life11111241. [PMID: 34833117 PMCID: PMC8617919 DOI: 10.3390/life11111241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 11/16/2022] Open
Abstract
Calmodulin (CaM) is a multifunctional calcium-binding protein, which regulates a variety of biochemical processes. CaM acts through its conformational changes and complex formation with its target enzymes. CaM consists of two globular domains (N-lobe and C-lobe) linked by an extended linker region. Upon calcium binding, the N-lobe and C-lobe undergo local conformational changes, followed by a major conformational change of the entire CaM to wrap the target enzyme. However, the regulation mechanisms, such as allosteric interactions, which regulate the large structural changes, are still unclear. In order to investigate the series of structural changes, the free-energy landscape of CaM was obtained by multi-scale divide-and-conquer molecular dynamics (MSDC-MD). The resultant free-energy landscape (FEL) shows that the Ca2+ bound CaM (holo-CaM) would take an experimentally famous elongated structure, which can be formed in the early stage of structural change, by breaking the inter-domain interactions. The FEL also shows that important interactions complete the structural change from the elongated structure to the ring-like structure. In addition, the FEL might give a guiding principle to predict mutational sites in CaM. In this study, it was demonstrated that the movement process of macroscopic variables on the FEL may be diffusive to some extent, and then, the MSDC-MD is suitable to the parallel computation.
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4
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Simultaneous detection of reciprocal interactions between calmodulin, Ca2+ and molecular targets: a focus on the calmodulin-RyR2 complex. Biochem J 2021; 478:487-491. [PMID: 33544125 DOI: 10.1042/bcj20200818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 01/22/2023]
Abstract
In a recent issue of Biochemical Journal, Brohus et al. (Biochem. J.476, 193-209) investigated the interaction between the ubiquitous intracellular Ca2+-sensor calmodulin (CaM) and peptides that mimic different structural regions of the cardiac ryanodine receptor (RyR2) at different Ca2+ concentrations. For the purpose, a novel bidimensional titration assay based on changes in fluorescence anisotropy was designed. The study identified the CaM domains that selectively bind to a specific CaM-binding domain in RyR2 and demonstrated that the interaction occurs essentially under Ca2+-saturating conditions. This study provides an elegant and experimentally accessible framework for detailed molecular investigations of the emerging life-threatening arrhythmia diseases associated with mutations in the genes encoding CaM. Furthermore, by allowing the measurement of the equilibrium dissociation constant in a protein-protein complex as a function of [Ca2+], the methodology presented by Brohus et al. may have broad applicability to the study of Ca2+ signalling.
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5
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Dürvanger Z, Harmat V. Structural Diversity in Calmodulin - Peptide Interactions. Curr Protein Pept Sci 2020; 20:1102-1111. [PMID: 31553290 DOI: 10.2174/1389203720666190925101937] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 03/13/2019] [Accepted: 04/12/2019] [Indexed: 01/17/2023]
Abstract
Calmodulin (CaM) is a highly conserved eukaryotic Ca2+ sensor protein that is able to bind a large variety of target sequences without a defined consensus sequence. The recognition of this diverse target set allows CaM to take part in the regulation of several vital cell functions. To fully understand the structural basis of the regulation functions of CaM, the investigation of complexes of CaM and its targets is essential. In this minireview we give an outline of the different types of CaM - peptide complexes with 3D structure determined, also providing an overview of recently determined structures. We discuss factors defining the orientations of peptides within the complexes, as well as roles of anchoring residues. The emphasis is on complexes where multiple binding modes were found.
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Affiliation(s)
- Zsolt Dürvanger
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary
| | - Veronika Harmat
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary.,MTA-ELTE Protein Modelling Research Group, Budapest, Hungary
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Porter JJ, Jang HS, Haque MM, Stuehr DJ, Mehl RA. Tyrosine nitration on calmodulin enhances calcium-dependent association and activation of nitric-oxide synthase. J Biol Chem 2019; 295:2203-2211. [PMID: 31914408 DOI: 10.1074/jbc.ra119.010999] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 12/19/2019] [Indexed: 12/14/2022] Open
Abstract
Production of reactive oxygen species caused by dysregulated endothelial nitric-oxide synthase (eNOS) activity is linked to vascular dysfunction. eNOS is a major target protein of the primary calcium-sensing protein calmodulin. Calmodulin is often modified by the main biomarker of nitroxidative stress, 3-nitrotyrosine (nitroTyr). Despite nitroTyr being an abundant post-translational modification on calmodulin, the mechanistic role of this modification in altering calmodulin function and eNOS activation has not been investigated. Here, using genetic code expansion to site-specifically nitrate calmodulin at its two tyrosine residues, we assessed the effects of these alterations on calcium binding by calmodulin and on binding and activation of eNOS. We found that nitroTyr-calmodulin retains affinity for eNOS under resting physiological calcium concentrations. Results from in vitro eNOS assays with calmodulin nitrated at Tyr-99 revealed that this nitration reduces nitric-oxide production and increases eNOS decoupling compared with WT calmodulin. In contrast, calmodulin nitrated at Tyr-138 produced more nitric oxide and did so more efficiently than WT calmodulin. These results indicate that the nitroTyr post-translational modification, like tyrosine phosphorylation, can impact calmodulin sensitivity for calcium and reveal Tyr site-specific gain or loss of functions for calmodulin-induced eNOS activation.
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Affiliation(s)
- Joseph J Porter
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331
| | - Hyo Sang Jang
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331
| | - Mohammad Mahfuzul Haque
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Dennis J Stuehr
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331.
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7
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Tejero J, Shiva S, Gladwin MT. Sources of Vascular Nitric Oxide and Reactive Oxygen Species and Their Regulation. Physiol Rev 2019; 99:311-379. [PMID: 30379623 DOI: 10.1152/physrev.00036.2017] [Citation(s) in RCA: 271] [Impact Index Per Article: 54.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nitric oxide (NO) is a small free radical with critical signaling roles in physiology and pathophysiology. The generation of sufficient NO levels to regulate the resistance of the blood vessels and hence the maintenance of adequate blood flow is critical to the healthy performance of the vasculature. A novel paradigm indicates that classical NO synthesis by dedicated NO synthases is supplemented by nitrite reduction pathways under hypoxia. At the same time, reactive oxygen species (ROS), which include superoxide and hydrogen peroxide, are produced in the vascular system for signaling purposes, as effectors of the immune response, or as byproducts of cellular metabolism. NO and ROS can be generated by distinct enzymes or by the same enzyme through alternate reduction and oxidation processes. The latter oxidoreductase systems include NO synthases, molybdopterin enzymes, and hemoglobins, which can form superoxide by reduction of molecular oxygen or NO by reduction of inorganic nitrite. Enzymatic uncoupling, changes in oxygen tension, and the concentration of coenzymes and reductants can modulate the NO/ROS production from these oxidoreductases and determine the redox balance in health and disease. The dysregulation of the mechanisms involved in the generation of NO and ROS is an important cause of cardiovascular disease and target for therapy. In this review we will present the biology of NO and ROS in the cardiovascular system, with special emphasis on their routes of formation and regulation, as well as the therapeutic challenges and opportunities for the management of NO and ROS in cardiovascular disease.
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Affiliation(s)
- Jesús Tejero
- Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania ; Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania ; Department of Pharmacology and Chemical Biology, University of Pittsburgh , Pittsburgh, Pennsylvania ; and Department of Medicine, Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Sruti Shiva
- Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania ; Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania ; Department of Pharmacology and Chemical Biology, University of Pittsburgh , Pittsburgh, Pennsylvania ; and Department of Medicine, Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Mark T Gladwin
- Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania ; Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania ; Department of Pharmacology and Chemical Biology, University of Pittsburgh , Pittsburgh, Pennsylvania ; and Department of Medicine, Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
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8
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Shimoyama H. A structural comparison of ‘real’ and ‘model’ calmodulin clarified allosteric interactions regulating domain motion. J Biomol Struct Dyn 2018; 37:1567-1581. [DOI: 10.1080/07391102.2018.1462730] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Hiromitsu Shimoyama
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
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9
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La Verde V, Dominici P, Astegno A. Towards Understanding Plant Calcium Signaling through Calmodulin-Like Proteins: A Biochemical and Structural Perspective. Int J Mol Sci 2018; 19:E1331. [PMID: 29710867 PMCID: PMC5983762 DOI: 10.3390/ijms19051331] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 11/17/2022] Open
Abstract
Ca2+ ions play a key role in a wide variety of environmental responses and developmental processes in plants, and several protein families with Ca2+-binding domains have evolved to meet these needs, including calmodulin (CaM) and calmodulin-like proteins (CMLs). These proteins have no catalytic activity, but rather act as sensor relays that regulate downstream targets. While CaM is well-studied, CMLs remain poorly characterized at both the structural and functional levels, even if they are the largest class of Ca2+ sensors in plants. The major structural theme in CMLs consists of EF-hands, and variations in these domains are predicted to significantly contribute to the functional versatility of CMLs. Herein, we focus on recent advances in understanding the features of CMLs from biochemical and structural points of view. The analysis of the metal binding and structural properties of CMLs can provide valuable insight into how such a vast array of CML proteins can coexist, with no apparent functional redundancy, and how these proteins contribute to cellular signaling while maintaining properties that are distinct from CaM and other Ca2+ sensors. An overview of the principal techniques used to study the biochemical properties of these interesting Ca2+ sensors is also presented.
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Affiliation(s)
- Valentina La Verde
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy.
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy.
| | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy.
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10
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Hanson QM, Carley JR, Gilbreath TJ, Smith BC, Underbakke ES. Calmodulin-induced Conformational Control and Allostery Underlying Neuronal Nitric Oxide Synthase Activation. J Mol Biol 2018; 430:935-947. [PMID: 29458127 DOI: 10.1016/j.jmb.2018.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/07/2018] [Accepted: 02/07/2018] [Indexed: 10/18/2022]
Abstract
Nitric oxide synthase (NOS) is the primary generator of nitric oxide signals controlling diverse physiological processes such as neurotransmission and vasodilation. NOS activation is contingent on Ca2+/calmodulin binding at a linker between its oxygenase and reductase domains to induce large conformational changes that orchestrate inter-domain electron transfer. However, the structural dynamics underlying activation of full-length NOS remain ambiguous. Employing hydrogen-deuterium exchange mass spectrometry, we reveal mechanisms underlying neuronal NOS activation by calmodulin and regulation by phosphorylation. We demonstrate that calmodulin binding orders the junction between reductase and oxygenase domains, exposes the FMN subdomain, and elicits a more dynamic oxygenase active site. Furthermore, we demonstrate that phosphorylation partially mimics calmodulin activation to modulate neuronal NOS activity via long-range allostery. Calmodulin binding and phosphorylation ultimately promote a more dynamic holoenzyme while coordinating inter-domain communication and electron transfer.
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Affiliation(s)
- Quinlin M Hanson
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Jeffrey R Carley
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Tyler J Gilbreath
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Brian C Smith
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Eric S Underbakke
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
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11
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Chemin J, Taiakina V, Monteil A, Piazza M, Guan W, Stephens RF, Kitmitto A, Pang ZP, Dolphin AC, Perez-Reyes E, Dieckmann T, Guillemette JG, Spafford JD. Calmodulin regulates Ca v3 T-type channels at their gating brake. J Biol Chem 2017; 292:20010-20031. [PMID: 28972185 PMCID: PMC5723990 DOI: 10.1074/jbc.m117.807925] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/19/2017] [Indexed: 01/10/2023] Open
Abstract
Calcium (Cav1 and Cav2) and sodium channels possess homologous CaM-binding motifs, known as IQ motifs in their C termini, which associate with calmodulin (CaM), a universal calcium sensor. Cav3 T-type channels, which serve as pacemakers of the mammalian brain and heart, lack a C-terminal IQ motif. We illustrate that T-type channels associate with CaM using co-immunoprecipitation experiments and single particle cryo-electron microscopy. We demonstrate that protostome invertebrate (LCav3) and human Cav3.1, Cav3.2, and Cav3.3 T-type channels specifically associate with CaM at helix 2 of the gating brake in the I-II linker of the channels. Isothermal titration calorimetry results revealed that the gating brake and CaM bind each other with high-nanomolar affinity. We show that the gating brake assumes a helical conformation upon binding CaM, with associated conformational changes to both CaM lobes as indicated by amide chemical shifts of the amino acids of CaM in 1H-15N HSQC NMR spectra. Intact Ca2+-binding sites on CaM and an intact gating brake sequence (first 39 amino acids of the I-II linker) were required in Cav3.2 channels to prevent the runaway gating phenotype, a hyperpolarizing shift in voltage sensitivities and faster gating kinetics. We conclude that the presence of high-nanomolar affinity binding sites for CaM at its universal gating brake and its unique form of regulation via the tuning of the voltage range of activity could influence the participation of Cav3 T-type channels in heart and brain rhythms. Our findings may have implications for arrhythmia disorders arising from mutations in the gating brake or CaM.
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Affiliation(s)
- Jean Chemin
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier F-34094, France
| | | | - Arnaud Monteil
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, Montpellier F-34094, France
| | - Michael Piazza
- Departments of Chemistry, Waterloo, Ontario N2L 3G1, Canada
| | - Wendy Guan
- Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | | | - Ashraf Kitmitto
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, United Kingdom
| | - Zhiping P Pang
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | | | | | - J David Spafford
- Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
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12
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Zhang P, Tripathi S, Trinh H, Cheung MS. Opposing Intermolecular Tuning of Ca 2+ Affinity for Calmodulin by Neurogranin and CaMKII Peptides. Biophys J 2017; 112:1105-1119. [PMID: 28355539 PMCID: PMC5374985 DOI: 10.1016/j.bpj.2017.01.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/27/2016] [Accepted: 01/23/2017] [Indexed: 12/03/2022] Open
Abstract
We investigated the impact of bound calmodulin (CaM)-target compound structure on the affinity of calcium (Ca2+) by integrating coarse-grained models and all-atomistic simulations with nonequilibrium physics. We focused on binding between CaM and two specific targets, Ca2+/CaM-dependent protein kinase II (CaMKII) and neurogranin (Ng), as they both regulate CaM-dependent Ca2+ signaling pathways in neurons. It was shown experimentally that Ca2+/CaM (holoCaM) binds to the CaMKII peptide with overwhelmingly higher affinity than Ca2+-free CaM (apoCaM); the binding of CaMKII peptide to CaM in return increases the Ca2+ affinity for CaM. However, this reciprocal relation was not observed in the Ng peptide (Ng13–49), which binds to apoCaM or holoCaM with binding affinities of the same order of magnitude. Unlike the holoCaM-CaMKII peptide, whose structure can be determined by crystallography, the structural description of the apoCaM-Ng13–49 is unknown due to low binding affinity, therefore we computationally generated an ensemble of apoCaM-Ng13–49 structures by matching the changes in the chemical shifts of CaM upon Ng13–49 binding from nuclear magnetic resonance experiments. Next, we computed the changes in Ca2+ affinity for CaM with and without binding targets in atomistic models using Jarzynski’s equality. We discovered the molecular underpinnings of lowered affinity of Ca2+ for CaM in the presence of Ng13–49 by showing that the N-terminal acidic region of Ng peptide pries open the β-sheet structure between the Ca2+ binding loops particularly at C-domain of CaM, enabling Ca2+ release. In contrast, CaMKII peptide increases Ca2+ affinity for the C-domain of CaM by stabilizing the two Ca2+ binding loops. We speculate that the distinctive structural difference in the bound complexes of apoCaM-Ng13–49 and holoCaM-CaMKII delineates the importance of CaM’s progressive mechanism of target binding on its Ca2+ binding affinities.
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Affiliation(s)
- Pengzhi Zhang
- Department of Physics, University of Houston, Houston, Texas
| | | | - Hoa Trinh
- Department of Physics, University of Houston, Houston, Texas
| | - Margaret S Cheung
- Department of Physics, University of Houston, Houston, Texas; Center for Theoretical Biological Physics, Rice University, Houston, Texas.
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13
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Carpenter MC, Palmer AE. Native and engineered sensors for Ca 2+ and Zn 2+: lessons from calmodulin and MTF1. Essays Biochem 2017; 61:237-243. [PMID: 28487400 PMCID: PMC6016828 DOI: 10.1042/ebc20160069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 01/16/2023]
Abstract
Ca2+ and Zn2+ dynamics have been identified as important drivers of physiological processes. In order for these dynamics to encode function, the cell must have sensors that transduce changes in metal concentration to specific downstream actions. Here we compare and contrast the native metal sensors: calmodulin (CaM), the quintessential Ca2+ sensor and metal-responsive transcription factor 1 (MTF1), a candidate Zn2+ sensor. While CaM recognizes and modulates the activity of hundreds of proteins through allosteric interactions, MTF1 recognizes a single DNA motif that is distributed throughout the genome regulating the transcription of many target genes. We examine how the different inorganic chemistries of these two metal ions may shape these different mechanisms transducing metal ion concentration into changing physiologic activity. In addition to native metal sensors, scientists have engineered sensors to spy on the dynamic changes of metals in cells. The inorganic chemistry of the metals shapes the possibilities in the design strategies of engineered sensors. We examine how different strategies to tune the affinities of engineered sensors mirror the strategies nature developed to sense both Ca2+ and Zn2+ in cells.
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Affiliation(s)
- Margaret C Carpenter
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80305, U.S.A
| | - Amy E Palmer
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80305, U.S.A.
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14
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Interplay of myosin phosphatase and protein phosphatase-2A in the regulation of endothelial nitric-oxide synthase phosphorylation and nitric oxide production. Sci Rep 2017; 7:44698. [PMID: 28300193 PMCID: PMC5353758 DOI: 10.1038/srep44698] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 02/13/2017] [Indexed: 01/07/2023] Open
Abstract
The inhibitory phosphorylation of endothelial nitric oxide (NO) synthase (eNOS) at Thr497 (eNOSpThr497) by protein kinase C or RhoA-activated kinase is a major regulatory determinant of eNOS activity. The signalling mechanisms involved in the dephosphorylation of eNOSpThr497 have not yet been clarified. This study identifies myosin phosphatase (MP) holoenzyme consisting of protein phosphatase-1 catalytic subunit (PP1c) and MP target subunit-1 (MYPT1) as an eNOSpThr497 phosphatase. In support of this finding are: (i) eNOS and MYPT1 interacts in various endothelial cells (ECs) and in in vitro binding assays (ii) MYPT1 targets and stimulates PP1c toward eNOSpThr497 substrate (iii) phosphorylation of MYPT1 at Thr696 (MYPT1pThr696) controls the activity of MP on eNOSpThr497. Phosphatase inhibition suppresses both NO production and transendothelial resistance (TER) of ECs. In contrast, epigallocatechin-3-gallate (EGCG) signals ECs via the 67 kDa laminin-receptor (67LR) resulting in protein kinase A dependent activation of protein phosphatase-2A (PP2A). PP2A dephosphorylates MYPT1pThr696 and thereby stimulates MP activity inducing dephosphorylation of eNOSpThr497 and the 20 kDa myosin II light chains. Thus an interplay of MP and PP2A is involved in the physiological regulation of EC functions implying that an EGCG dependent activation of these phosphatases leads to enhanced NO production and EC barrier improvement.
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15
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Piazza M, Dieckmann T, Guillemette JG. Structural Studies of a Complex Between Endothelial Nitric Oxide Synthase and Calmodulin at Physiological Calcium Concentration. Biochemistry 2016; 55:5962-5971. [DOI: 10.1021/acs.biochem.6b00821] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael Piazza
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Thorsten Dieckmann
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - J. Guy Guillemette
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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16
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Shukla D, Peck A, Pande VS. Conformational heterogeneity of the calmodulin binding interface. Nat Commun 2016; 7:10910. [PMID: 27040077 PMCID: PMC4822001 DOI: 10.1038/ncomms10910] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 01/28/2016] [Indexed: 01/13/2023] Open
Abstract
Calmodulin (CaM) is a ubiquitous Ca(2+) sensor and a crucial signalling hub in many pathways aberrantly activated in disease. However, the mechanistic basis of its ability to bind diverse signalling molecules including G-protein-coupled receptors, ion channels and kinases remains poorly understood. Here we harness the high resolution of molecular dynamics simulations and the analytical power of Markov state models to dissect the molecular underpinnings of CaM binding diversity. Our computational model indicates that in the absence of Ca(2+), sub-states in the folded ensemble of CaM's C-terminal domain present chemically and sterically distinct topologies that may facilitate conformational selection. Furthermore, we find that local unfolding is off-pathway for the exchange process relevant for peptide binding, in contrast to prior hypotheses that unfolding might account for binding diversity. Finally, our model predicts a novel binding interface that is well-populated in the Ca(2+)-bound regime and, thus, a candidate for pharmacological intervention.
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Affiliation(s)
- Diwakar Shukla
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
- SIMBIOS NIH Center for Biomedical Computation, Stanford University, Stanford, California 94305, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Ariana Peck
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Vijay S. Pande
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
- SIMBIOS NIH Center for Biomedical Computation, Stanford University, Stanford, California 94305, USA
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17
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Astegno A, La Verde V, Marino V, Dell'Orco D, Dominici P. Biochemical and biophysical characterization of a plant calmodulin: Role of the N- and C-lobes in calcium binding, conformational change, and target interaction. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1864:297-307. [PMID: 26708477 DOI: 10.1016/j.bbapap.2015.12.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/29/2015] [Accepted: 12/09/2015] [Indexed: 12/22/2022]
Abstract
In plants, transient elevation of intracellular Ca(2+) concentration in response to abiotic stress is responsible for glutamate decarboxylase (GAD) activation via association with calmodulin (CaM), an EF-hand protein consisting of two homologous domains (N and C). An unusual 1:2 binding mode of CaM to CaM-binding domains of GAD has long been known, however the contribution of the two CaM domains in target recognition and activation remains to be clarified. Here, we explored the coupling between physicochemical properties of Arabidopsis CaM1 (AtCaM1) and Arabidopsis GAD1 activation, focusing on each AtCaM1 lobe. We found that the four EF-loops of AtCaM1 differently contribute to the ~20 μM apparent affinity for Ca(2+) and the C-lobe shows a ~6-fold higher affinity than N-lobe (Kd(app) 5.6 μM and 32 μM for C- and N-lobes, respectively). AtCaM1 responds structurally to Ca(2+) in a manner similar to vertebrate CaM based on comparison of Ca(2+)-induced changes in hydrophobicity exposure, secondary structure, and hydrodynamic behavior. Molecular dynamics simulations of AtCaM1 apo and Ca(2+)-bound reveal that the latter state is significantly less flexible, although regions of the N-lobe remain quite flexible; this suggests the importance of N-lobe for completing the transition to the extended structure of holoprotein, consistent with data from ANS fluorescence, CD spectroscopy, and SEC analysis. Moreover, enzymatic analysis reveal that mutations in the two lobes affect GAD1 activation in similar ways and only intact AtCaM1 can fully activate GAD1. Taken together, our data provide new insights into the CaM lobes role in interactions between CaM and plant GAD.
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Affiliation(s)
| | | | - Valerio Marino
- Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy
| | - Daniele Dell'Orco
- Department of Neurological, Biomedical and Movement Sciences, University of Verona, Verona, Italy
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Verona, Italy
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18
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Maaty WS, Weis DD. Label-Free, In-Solution Screening of Peptide Libraries for Binding to Protein Targets Using Hydrogen Exchange Mass Spectrometry. J Am Chem Soc 2016; 138:1335-43. [PMID: 26741284 DOI: 10.1021/jacs.5b11742] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is considerable interest in the discovery of peptide ligands that bind to protein targets. Discovery of such ligands is usually approached by screening large peptide libraries. However, the individual peptides must be tethered to a tag that preserves their individual identities (e.g., phage display or one-bead one-compound). To overcome this limitation, we have developed a method for screening libraries of label-free peptides for binding to a protein target in solution as a single batch. The screening is based on decreased amide hydrogen exchange by peptides that bind to the target. Hydrogen exchange is measured by mass spectrometry. We demonstrate the approach using a peptide library derived from the Escherichia coli proteome that contained 6664 identifiable features. The library was spiked separately with a peptide spanning the calmodulin binding domain of endothelial nitric oxide synthase (eNOS, 494-513) and a peptide spanning the N-terminal 20 residues of bovine ribonuclease A (S peptide). Human calmodulin and bovine ribonuclease S (RNase S) were screened against the library. Using a novel data analysis workflow, we identified the eNOS peptide as the only calmodulin binding peptide and S peptide as the only ribonuclease S binding peptide in the library.
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Affiliation(s)
- Walid S Maaty
- Department of Nucleic Acid and Protein Structure, Agricultural Genetic Engineering Research Institute, Agricultural Research Center , Giza 12619, Egypt
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19
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Samson R, Lee A, Lawless S, Hsu R, Sander G. Novel Pathophysiological Mechanisms in Hypertension. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 956:21-35. [PMID: 27981434 DOI: 10.1007/5584_2016_96] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hypertension is the most common disease affecting humans and imparts a significant cardiovascular and renal risk to patients. Extensive research over the past few decades has enhanced our understanding of the underlying mechanisms in hypertension. However, in most instances, the cause of hypertension in a given patient continues to remain elusive. Nevertheless, achieving aggressive blood pressure goals significantly reduces cardiovascular morbidity and mortality, as demonstrated in the recently concluded SPRINT trial. Since a large proportion of patients still fail to achieve blood pressure goals, knowledge of novel pathophysiologic mechanisms and mechanism based treatment strategies is crucial. The following chapter will review the novel pathophysiological mechanisms in hypertension, with a focus on role of immunity, inflammation and vascular endothelial homeostasis. The therapeutic implications of these mechanisms will be discussed where applicable.
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Affiliation(s)
- Rohan Samson
- Tulane University Heart and Vascular Institute, Tulane School of Medicine, 1430 Tulane Avenue, SL-48, New Orleans, LA, 70112, USA.
| | - Andrew Lee
- Tulane University Heart and Vascular Institute, Tulane School of Medicine, 1430 Tulane Avenue, SL-48, New Orleans, LA, 70112, USA
| | - Sean Lawless
- Tulane University Heart and Vascular Institute, Tulane School of Medicine, 1430 Tulane Avenue, SL-48, New Orleans, LA, 70112, USA
| | - Robert Hsu
- Tulane University Heart and Vascular Institute, Tulane School of Medicine, 1430 Tulane Avenue, SL-48, New Orleans, LA, 70112, USA
| | - Gary Sander
- Tulane University Heart and Vascular Institute, Tulane School of Medicine, 1430 Tulane Avenue, SL-48, New Orleans, LA, 70112, USA
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20
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Shu X, Keller TCS, Begandt D, Butcher JT, Biwer L, Keller AS, Columbus L, Isakson BE. Endothelial nitric oxide synthase in the microcirculation. Cell Mol Life Sci 2015; 72:4561-75. [PMID: 26390975 PMCID: PMC4628887 DOI: 10.1007/s00018-015-2021-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/21/2015] [Accepted: 08/11/2015] [Indexed: 02/07/2023]
Abstract
Endothelial nitric oxide synthase (eNOS, NOS3) is responsible for producing nitric oxide (NO)--a key molecule that can directly (or indirectly) act as a vasodilator and anti-inflammatory mediator. In this review, we examine the structural effects of regulation of the eNOS enzyme, including post-translational modifications and subcellular localization. After production, NO diffuses to surrounding cells with a variety of effects. We focus on the physiological role of NO and NO-derived molecules, including microvascular effects on vessel tone and immune response. Regulation of eNOS and NO action is complicated; we address endogenous and exogenous mechanisms of NO regulation with a discussion of pharmacological agents used in clinical and laboratory settings and a proposed role for eNOS in circulating red blood cells.
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Affiliation(s)
- Xiaohong Shu
- College of Pharmacy, Dalian Medical University, Dalian, 116044, China
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
| | - T C Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, USA
| | - Daniela Begandt
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
| | - Joshua T Butcher
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
| | - Lauren Biwer
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, USA
| | - Alexander S Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, USA
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VA, 22908, USA.
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, USA.
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21
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Sheng Y, Zhong L, Guo D, Lau G, Feng C. Insight into structural rearrangements and interdomain interactions related to electron transfer between flavin mononucleotide and heme in nitric oxide synthase: A molecular dynamics study. J Inorg Biochem 2015; 153:186-196. [PMID: 26277414 DOI: 10.1016/j.jinorgbio.2015.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Revised: 06/29/2015] [Accepted: 08/05/2015] [Indexed: 10/23/2022]
Abstract
Calmodulin (CaM) binding to nitric oxide synthase (NOS) enables a conformational change, in which the FMN domain shuttles between the FAD and heme domains to deliver electrons to the active site heme center. A clear understanding of this large conformational change is critical, since this step is the rate-limiting in NOS catalysis. Herein molecular dynamics simulations were conducted on a model of an oxygenase/FMN (oxyFMN) construct of human inducible NOS (iNOS). This is to investigate the structural rearrangements and the domain interactions related to the FMN-heme interdomain electron transfer (IET). We carried out simulations on the iNOS oxyFMN·CaM complex models in [Fe(III)][FMNH(-)] and [Fe(II)][FMNH] oxidation states, the pre- and post-IET states. The comparison of the dynamics and conformations of the iNOS construct at the two oxidation states has allowed us to identify key factors related to facilitating the FMN-heme IET process. The computational results demonstrated, for the first time, that the conformational change is redox-dependent. Predictions of the key interacting sites in optimal interdomain FMN/heme docking are well supported by experimental data in the literature. An intra-subunit pivot region is predicted to modulate the FMN domain motion and correlate with existence of a bottleneck in the conformational sampling that leads to the electron transfer-competent state. Interactions of the residues identified in this work are proposed to ensure that the FMN domain moves with appropriate degrees of freedom and docks to proper positions at the heme domain, resulting in efficient IET and nitric oxide production.
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Affiliation(s)
- Yinghong Sheng
- Department of Chemistry & Physics, College of Arts & Sciences, Florida Gulf Coast University, 10501 FGCU Blvd. S., Fort Myers, FL 33965, USA.
| | - Linghao Zhong
- Pennsylvania State University at Mont Alto, 1 Campus Drive, Mont Alto, PA 17237, USA
| | - Dahai Guo
- Department of Bioengineering and Software Engineering, U.A. Whitaker College of Engineering, Florida Gulf Coast University, 10501 FGCU Blvd. S., Fort Myers, FL 33965, USA
| | - Gavin Lau
- Department of Chemistry & Physics, College of Arts & Sciences, Florida Gulf Coast University, 10501 FGCU Blvd. S., Fort Myers, FL 33965, USA
| | - Changjian Feng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, USA.
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22
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Abstract
For >50 years, it has been recognized that immunity contributes to hypertension. Recent data have defined an important role of T cells and various T cell-derived cytokines in several models of experimental hypertension. These studies have shown that stimuli like angiotensin II, deoxycorticosterone acetate-salt, and excessive catecholamines lead to formation of effector like T cells that infiltrate the kidney and perivascular regions of both large arteries and arterioles. There is also accumulation of monocyte/macrophages in these regions. Cytokines released from these cells, including interleukin-17, interferon-γ, tumor necrosis factorα, and interleukin-6 promote both renal and vascular dysfunction and damage, leading to enhanced sodium retention and increased systemic vascular resistance. The renal effects of these cytokines remain to be fully defined, but include enhanced formation of angiotensinogen, increased sodium reabsorption, and increased renal fibrosis. Recent experiments have defined a link between oxidative stress and immune activation in hypertension. These have shown that hypertension is associated with formation of reactive oxygen species in dendritic cells that lead to formation of gamma ketoaldehydes, or isoketals. These rapidly adduct to protein lysines and are presented by dendritic cells as neoantigens that activate T cells and promote hypertension. Thus, cells of both the innate and adaptive immune system contribute to end-organ damage and dysfunction in hypertension. Therapeutic interventions to reduce activation of these cells may prove beneficial in reducing end-organ damage and preventing consequences of hypertension, including myocardial infarction, heart failure, renal failure, and stroke.
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Affiliation(s)
- William G McMaster
- From the Department of Surgery, Division of Clinical Pharmacology (W.G.M.) and the Department of Medicine (W.G.M., A.K., M.S.M., D.G.H.), Vanderbilt University School of Medicine, Nashville, TN
| | - Annet Kirabo
- From the Department of Surgery, Division of Clinical Pharmacology (W.G.M.) and the Department of Medicine (W.G.M., A.K., M.S.M., D.G.H.), Vanderbilt University School of Medicine, Nashville, TN
| | - Meena S Madhur
- From the Department of Surgery, Division of Clinical Pharmacology (W.G.M.) and the Department of Medicine (W.G.M., A.K., M.S.M., D.G.H.), Vanderbilt University School of Medicine, Nashville, TN
| | - David G Harrison
- From the Department of Surgery, Division of Clinical Pharmacology (W.G.M.) and the Department of Medicine (W.G.M., A.K., M.S.M., D.G.H.), Vanderbilt University School of Medicine, Nashville, TN.
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23
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Piazza M, Guillemette JG, Dieckmann T. Dynamics of nitric oxide synthase-calmodulin interactions at physiological calcium concentrations. Biochemistry 2015; 54:1989-2000. [PMID: 25751535 DOI: 10.1021/bi501353s] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The intracellular Ca²⁺ concentration is an important regulator of many cellular functions. The small acidic protein calmodulin (CaM) serves as a Ca²⁺ sensor and control element for many enzymes. Nitric oxide synthase (NOS) is one of the proteins that is activated by CaM and plays a major role in a number of key physiological and pathological processes. Previous studies have shown CaM to act like a switch that causes a conformational change in NOS to allow for the electron transfer between the reductase and oxygenase domains through a process that is thought to be highly dynamic. We have analyzed the structure and dynamics of complexes formed by peptides based on inducible NOS (iNOS) and endothelial NOS (eNOS) with CaM at Ca²⁺ concentrations that mimic the physiological basal (17 and 100 nM) and elevated levels (225 nM) found in mammalian cells using fluorescence techniques and nuclear magnetic resonance spectroscopy. The results show the CaM-NOS complexes have similar structures at physiological and fully saturated Ca²⁺ levels; however, their dynamics are remarkably different. At 225 nM Ca²⁺, the CaM-NOS complexes show overall an increase in backbone dynamics, when compared to the dynamics of the complexes at saturating Ca²⁺ concentrations. Specifically, the N-lobe of CaM in the CaM-iNOS complex displays a lower internal mobility (higher S²) and higher exchange protection compared to those of the CaM-eNOS complex. In contrast, the C-lobe of CaM in the CaM-eNOS complex is less dynamic. These results illustrate that structures of CaM-NOS complexes determined at saturated Ca²⁺ concentrations cannot provide a complete picture because the differences in intramolecular dynamics become visible only at physiological Ca²⁺ levels.
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Affiliation(s)
- Michael Piazza
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - J Guy Guillemette
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Thorsten Dieckmann
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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24
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Astegno A, Maresi E, Marino V, Dominici P, Pedroni M, Piccinelli F, Dell'Orco D. Structural plasticity of calmodulin on the surface of CaF2 nanoparticles preserves its biological function. NANOSCALE 2014; 6:15037-47. [PMID: 25367003 DOI: 10.1039/c4nr04368e] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nanoparticles are increasingly used in biomedical applications and are especially attractive as biocompatible and biodegradable protein delivery systems. Herein, the interaction between biocompatible 25 nm CaF2 nanoparticles and the ubiquitous calcium sensor calmodulin has been investigated in order to assess the potential of these particles to serve as suitable surface protein carriers. Calmodulin is a multifunctional messenger protein that activates a wide variety of signaling pathways in eukaryotic cells by changing its conformation in a calcium-dependent manner. Isothermal titration calorimetry and circular dichroism studies have shown that the interaction between calmodulin and CaF2 nanoparticles occurs with physiologically relevant affinity and that the binding process is fully reversible, occurring without significant alterations in protein secondary and tertiary structures. Experiments performed with a mutant form of calmodulin having an impaired Ca(2+)-binding ability in the C-terminal lobe suggest that the EF-hand Ca(2+)-binding motifs are directly involved in the binding of calmodulin to the CaF2 matrix. The residual capability of nanoparticle-bound calmodulin to function as a calcium sensor protein, binding to and altering the activity of a target protein, was successfully probed by biochemical assays. Even if efficiently carried by CaF2 nanoparticles, calmodulin may dissociate, thus retaining the ability to bind the peptide encompassing the putative C-terminal calmodulin-binding domain of glutamate decarboxylase and activate the enzyme. We conclude that the high flexibility and structural plasticity of calmodulin are responsible for the preservation of its function when bound in high amounts to a nanoparticle surface.
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25
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The Ever Changing Moods of Calmodulin: How Structural Plasticity Entails Transductional Adaptability. J Mol Biol 2014; 426:2717-35. [DOI: 10.1016/j.jmb.2014.05.016] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 05/14/2014] [Accepted: 05/16/2014] [Indexed: 11/20/2022]
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