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Campiglio M, Dyrda A, Tuinte WE, Török E. Ca V1.1 Calcium Channel Signaling Complexes in Excitation-Contraction Coupling: Insights from Channelopathies. Handb Exp Pharmacol 2023; 279:3-39. [PMID: 36592225 DOI: 10.1007/164_2022_627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the mechanical coupling between two ion channels: the L-type voltage-gated calcium channel (CaV1.1), located in the sarcolemma and functioning as the voltage sensor of EC coupling, and the ryanodine receptor 1 (RyR1), located on the sarcoplasmic reticulum serving as the calcium release channel. To this day, the molecular mechanism by which these two ion channels are linked remains elusive. However, recently, skeletal muscle EC coupling could be reconstituted in heterologous cells, revealing that only four proteins are essential for this process: CaV1.1, RyR1, and the cytosolic proteins CaVβ1a and STAC3. Due to the crucial role of these proteins in skeletal muscle EC coupling, any mutation that affects any one of these proteins can have devastating consequences, resulting in congenital myopathies and other pathologies.Here, we summarize the current knowledge concerning these four essential proteins and discuss the pathophysiology of the CaV1.1, RyR1, and STAC3-related skeletal muscle diseases with an emphasis on the molecular mechanisms. Being part of the same signalosome, mutations in different proteins often result in congenital myopathies with similar symptoms or even in the same disease.
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Affiliation(s)
- Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
| | - Agnieszka Dyrda
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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Miotto MC, Weninger G, Dridi H, Yuan Q, Liu Y, Wronska A, Melville Z, Sittenfeld L, Reiken S, Marks AR. Structural analyses of human ryanodine receptor type 2 channels reveal the mechanisms for sudden cardiac death and treatment. SCIENCE ADVANCES 2022; 8:eabo1272. [PMID: 35857850 PMCID: PMC9299551 DOI: 10.1126/sciadv.abo1272] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 06/03/2022] [Indexed: 05/29/2023]
Abstract
Ryanodine receptor type 2 (RyR2) mutations have been linked to an inherited form of exercise-induced sudden cardiac death called catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT results from stress-induced sarcoplasmic reticular Ca2+ leak via the mutant RyR2 channels during diastole. We present atomic models of human wild-type (WT) RyR2 and the CPVT mutant RyR2-R2474S determined by cryo-electron microscopy with overall resolutions in the range of 2.6 to 3.6 Å, and reaching local resolutions of 2.25 Å, unprecedented for RyR2 channels. Under nonactivating conditions, the RyR2-R2474S channel is in a "primed" state between the closed and open states of WT RyR2, rendering it more sensitive to activation that results in stress-induced Ca2+ leak. The Rycal drug ARM210 binds to RyR2-R2474S, reverting the primed state toward the closed state. Together, these studies provide a mechanism for CPVT and for the therapeutic actions of ARM210.
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Affiliation(s)
- Marco C. Miotto
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Gunnar Weninger
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Haikel Dridi
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Qi Yuan
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Yang Liu
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Anetta Wronska
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Zephan Melville
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Leah Sittenfeld
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Steven Reiken
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Andrew R. Marks
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
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Woll KA, Van Petegem F. Calcium Release Channels: Structure and Function of IP3 Receptors and Ryanodine Receptors. Physiol Rev 2021; 102:209-268. [PMID: 34280054 DOI: 10.1152/physrev.00033.2020] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca2+-release channels are giant membrane proteins that control the release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. The two members, ryanodine receptors (RyRs) and inositol-1,4,5-trisphosphate Receptors (IP3Rs), are evolutionarily related and are both activated by cytosolic Ca2+. They share a common architecture, but RyRs have evolved additional modules in the cytosolic region. Their massive size allows for the regulation by tens of proteins and small molecules, which can affect the opening and closing of the channels. In addition to Ca2+, other major triggers include IP3 for the IP3Rs, and depolarization of the plasma membrane for a particular RyR subtype. Their size has made them popular targets for study via electron microscopic methods, with current structures culminating near 3Å. The available structures have provided many new mechanistic insights int the binding of auxiliary proteins and small molecules, how these can regulate channel opening, and the mechanisms of disease-associated mutations. They also help scrutinize previously proposed binding sites, as some of these are now incompatible with the structures. Many questions remain around the structural effects of post-translational modifications, additional binding partners, and the higher-order complexes these channels can make in situ. This review summarizes our current knowledge about the structures of Ca2+-release channels and how this informs on their function.
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Affiliation(s)
- Kellie A Woll
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
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Truong KM, Cherednichenko G, Pessah IN. Interactions of Dichlorodiphenyltrichloroethane (DDT) and Dichlorodiphenyldichloroethylene (DDE) With Skeletal Muscle Ryanodine Receptor Type 1. Toxicol Sci 2020; 170:509-524. [PMID: 31127943 DOI: 10.1093/toxsci/kfz120] [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] [Indexed: 12/16/2022] Open
Abstract
Dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) are ubiquitous in the environment and detected in tissues of living organisms. Although DDT owes its insecticidal activity to impeding closure of voltage-gated sodium channels, it mediates toxicity in mammals by acting as an endocrine disruptor (ED). Numerous studies demonstrate DDT/DDE to be EDs, but studies examining muscle-specific effects mediated by nonhormonal receptors in mammals are lacking. Therefore, we investigated whether o,p'-DDT, p,p'-DDT, o,p'-DDE, and p,p'-DDE (DDx, collectively) alter the function of ryanodine receptor type 1 (RyR1), a protein critical for skeletal muscle excitation-contraction coupling and muscle health. DDx (0.01-10 µM) elicited concentration-dependent increases in [3H]ryanodine ([3H]Ry) binding to RyR1 with o,p'-DDE showing highest potency and efficacy. DDx also showed sex differences in [3H]Ry-binding efficacy toward RyR1, where [3H]Ry-binding in female muscle preparations was greater than male counterparts. Measurements of Ca2+ transport across sarcoplasmic reticulum (SR) membrane vesicles further confirmed DDx can selectively engage with RyR1 to cause Ca2+ efflux from SR stores. DDx also disrupts RyR1-signaling in HEK293T cells stably expressing RyR1 (HEK-RyR1). Pretreatment with DDx (0.1-10 µM) for 100 s, 12 h, or 24 h significantly sensitized Ca2+-efflux triggered by RyR agonist caffeine in a concentration-dependent manner. o,p'-DDE (24 h; 1 µM) significantly increased Ca2+-transient amplitude from electrically stimulated mouse myotubes compared with control and displayed abnormal fatigability. In conclusion, our study demonstrates DDx can directly interact and modulate RyR1 conformation, thereby altering SR Ca2+-dynamics and sensitize RyR1-expressing cells to RyR1 activators, which may ultimately contribute to long-term impairments in muscle health.
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Affiliation(s)
- Kim M Truong
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616-5270
| | - Gennady Cherednichenko
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616-5270
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California 95616-5270
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5
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Ryanodine receptor modulation by caffeine challenge modifies Na + current properties in intact murine skeletal muscle fibres. Sci Rep 2020; 10:2199. [PMID: 32042141 PMCID: PMC7010675 DOI: 10.1038/s41598-020-59196-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 01/06/2020] [Indexed: 12/18/2022] Open
Abstract
We investigated effects of the ryanodine receptor (RyR) modulator caffeine on Na+ current (INa) activation and inactivation in intact loose-patch clamped murine skeletal muscle fibres subject to a double pulse procedure. INa activation was examined using 10-ms depolarising, V1, steps to varying voltages 0–80 mV positive to resting membrane potential. The dependence of the subsequent, INa inactivation on V1 was examined by superimposed, V2, steps to a fixed depolarising voltage. Current-voltage activation and inactivation curves indicated that adding 0.5 and 2 mM caffeine prior to establishing the patch seal respectively produced decreased (within 1 min) and increased (after ~2 min) peak INa followed by its recovery to pretreatment levels (after ~40 and ~30 min respectively). These changes accompanied negative shifts in the voltage dependence of INa inactivation (within 10 min) and subsequent superimposed positive activation and inactivation shifts, following 0.5 mM caffeine challenge. In contrast, 2 mM caffeine elicited delayed negative shifts in both activation and inactivation. These effects were abrogated if caffeine was added after establishing the patch seal or with RyR block by 10 μM dantrolene. These effects precisely paralleled previous reports of persistently (~10 min) increased cytosolic [Ca2+] with 0.5 mM, and an early peak rapidly succeeded by persistently reduced [Ca2+] likely reflecting gradual RyR inactivation with ≥1.0 mM caffeine. The latter findings suggested inhibitory effects of even resting cytosolic [Ca2+] on INa. They suggest potentially physiologically significant negative feedback regulation of RyR activity on Nav1.4 properties through increased or decreased local cytosolic [Ca2+], Ca2+-calmodulin and FKBP12.
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Richardson SJ, Steele GA, Gallant EM, Lam A, Schwartz CE, Board PG, Casarotto MG, Beard NA, Dulhunty AF. Association of FK506 binding proteins with RyR channels - effect of CLIC2 binding on sub-conductance opening and FKBP binding. J Cell Sci 2017; 130:3588-3600. [PMID: 28851804 DOI: 10.1242/jcs.204461] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 07/31/2017] [Indexed: 12/22/2022] Open
Abstract
Ryanodine receptor (RyR) Ca2+ channels are central to striated muscle function and influence signalling in neurons and other cell types. Beneficially low RyR activity and maximum conductance opening may be stabilised when RyRs bind to FK506 binding proteins (FKBPs) and destabilised by FKBP dissociation, with submaximal opening during RyR hyperactivity associated with myopathies and neurological disorders. However, the correlation with submaximal opening is debated and quantitative evidence is lacking. Here, we have measured altered FKBP binding to RyRs and submaximal activity with addition of wild-type (WT) CLIC2, an inhibitory RyR ligand, or its H101Q mutant that hyperactivates RyRs, which probably causes cardiac and intellectual abnormalities. The proportion of sub-conductance opening increases with WT and H101Q CLIC2 and is correlated with reduced FKBP-RyR association. The sub-conductance opening reduces RyR currents in the presence of WT CLIC2. In contrast, sub-conductance openings contribute to excess RyR 'leak' with H101Q CLIC2. There are significant FKBP and RyR isoform-specific actions of CLIC2, rapamycin and FK506 on FKBP-RyR association. The results show that FKBPs do influence RyR gating and would contribute to excess Ca2+ release in this CLIC2 RyR channelopathy.
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Affiliation(s)
- Spencer J Richardson
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
| | - Gregory A Steele
- Capital Pathology Laboratory, 70 Kent St, Deakin, ACT 2600, Australia
| | - Esther M Gallant
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
| | - Alexander Lam
- Neurosurgery, Royal Perth Hospital, 197 Wellington St, Perth, WA 6000, Australia
| | - Charles E Schwartz
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Philip G Board
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
| | - Marco G Casarotto
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
| | - Nicole A Beard
- Cardiac Physiology Department, Health Research Institute, Faculty of Education Science and Mathematics, University of Canberra, Bruce, ACT 2617, Australia
| | - Angela F Dulhunty
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
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7
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Yuchi Z, Van Petegem F. Ryanodine receptors under the magnifying lens: Insights and limitations of cryo-electron microscopy and X-ray crystallography studies. Cell Calcium 2016; 59:209-27. [DOI: 10.1016/j.ceca.2016.04.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/08/2016] [Accepted: 04/09/2016] [Indexed: 10/21/2022]
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8
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Zheng W. Toward decrypting the allosteric mechanism of the ryanodine receptor based on coarse-grained structural and dynamic modeling. Proteins 2015; 83:2307-18. [DOI: 10.1002/prot.24951] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 10/09/2015] [Accepted: 10/14/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Wenjun Zheng
- Department of Physics; State University of New York at Buffalo; Buffalo New York 14260
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9
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Van Petegem F. Ryanodine Receptors: Allosteric Ion Channel Giants. J Mol Biol 2015; 427:31-53. [DOI: 10.1016/j.jmb.2014.08.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/02/2014] [Accepted: 08/05/2014] [Indexed: 01/27/2023]
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10
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Strauss JD, Wagenknecht T. Structure of glutaraldehyde cross-linked ryanodine receptor. J Struct Biol 2013; 181:300-6. [PMID: 23333333 PMCID: PMC3587655 DOI: 10.1016/j.jsb.2013.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/04/2013] [Accepted: 01/09/2013] [Indexed: 01/01/2023]
Abstract
The ryanodine receptor (RyR) family of calcium release channels plays a vital role in excitation-contraction coupling (ECC). Along with the dihydropyridine receptor (DHPR), calsequestrin, and several other smaller regulatory and adaptor proteins, RyRs form a large dynamic complex referred to as ECC machinery. Here we describe a simple cross-linking procedure that can be used to stabilize fragile components of the ECC machinery, for the purpose of structural elucidation by single particle cryo-electron microscopy (cryo-EM). As a model system, the complex of the FK506-binding protein (FKBP12) and RyR1 was used to test the cross-linking protocol. Glutaraldehyde fixation led to complete cross-linking of receptor-bound FKBP12 to RyR1, and also to extensive cross-linking of the four subunits comprising RyR to one another without compromising the RyR1 ultrastructure. FKBP12 cross-linked with RyR1 was visualized in 2D averages by single particle cryo-EM. Comparison of control RyR1 and cross-linked RyR1 3D reconstructions revealed minor conformational changes at the transmembrane assembly and at the cytoplasmic region. Intersubunit cross-linking enhanced [(3)H]ryanodine binding to RyR1. Based on our findings we propose that intersubunit cross-linking of RyR1 by glutaraldehyde induced RyR1 to adopt an open like conformation.
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Affiliation(s)
- Joshua D. Strauss
- Wadsworth Center, New York State Department of Health, Albany, New York 12201
- Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201
| | - Terence Wagenknecht
- Wadsworth Center, New York State Department of Health, Albany, New York 12201
- Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Albany, NY 12201
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11
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Sun W, Wang L, Jiang H, Chen D, Murchie AI. Targeting mitochondrial transcription in fission yeast with ETB, an inhibitor of HSP60, the chaperone that binds to the mitochondrial transcription factor Mtf1. Genes Cells 2012; 17:122-31. [DOI: 10.1111/j.1365-2443.2011.01578.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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LI YM, JI GJ. Evolution in Research of Ryanodine Receptors and Its Subtype 2 Regulators*. PROG BIOCHEM BIOPHYS 2011. [DOI: 10.3724/sp.j.1206.2010.00518] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Blayney LM, Jones JL, Griffiths J, Lai FA. A mechanism of ryanodine receptor modulation by FKBP12/12.6, protein kinase A, and K201. Cardiovasc Res 2010; 85:68-78. [PMID: 19661110 DOI: 10.1093/cvr/cvp273] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS Our objective was to explore the functional interdependence of protein kinase A (PKA) phosphorylation with binding of modulatory FK506 binding proteins (FKBP12/12.6) to the ryanodine receptor (RyR). RyR type 1 or type 2 was prepared from rabbit skeletal muscle or pig cardiac muscle, respectively. In heart failure, RyR2 dysfunction is implicated in fatal arrhythmia and RyR1 dysfunction is associated with muscle fatigue. A controversial underlying mechanism of RyR1/2 dysfunction is proposed to be hyperphosphorylation of RyR1/2 by PKA, causing loss of FKBP12/12.6 binding that is reversible by the experimental inhibitory drug K201 (JTV519). Phosphorylation is also a trigger for fatal arrhythmia in catecholaminergic polymorphic ventricular tachycardia associated with point mutations in RyR2. METHODS AND RESULTS Equilibrium binding kinetics of RyR1/2 to FKBP12/12.6 were measured using surface plasmon resonance (Biacore). Free Ca(2+) concentration was used to modulate the open/closed conformation of RyR1/2 channels measured using [(3)H]ryanodine binding assays. The affinity constant-K(A), for RyR1/2 binding to FKBP12/12.6, was significantly greater for the closed compared with the open conformation. The effect of phosphorylation or K201 was to reduce the K(A) of the closed conformation by increasing the rate of dissociation k(d). K201 reduced [(3)H]ryanodine binding to RyR1/2 at all free Ca(2+) concentrations including PKA phosphorylated preparations. CONCLUSION The results are explained through a model proposing that phosphorylation and K201 acted similarly to change the conformation of RyR1/2 and regulate FKBP12/12.6 binding. K201 stabilized the conformation, whereas phosphorylation facilitated a subsequent molecular event that might increase the rate of an open/closed conformational transition.
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Affiliation(s)
- Lynda M Blayney
- Department of Medicine - Cardiology, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
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Blayney LM, Lai FA. Ryanodine receptor-mediated arrhythmias and sudden cardiac death. Pharmacol Ther 2009; 123:151-77. [PMID: 19345240 PMCID: PMC2704947 DOI: 10.1016/j.pharmthera.2009.03.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 03/03/2009] [Indexed: 12/25/2022]
Abstract
The cardiac ryanodine receptor-Ca2+ release channel (RyR2) is an essential sarcoplasmic reticulum (SR) transmembrane protein that plays a central role in excitation–contraction coupling (ECC) in cardiomyocytes. Aberrant spontaneous, diastolic Ca2+ leak from the SR due to dysfunctional RyR2 contributes to the formation of delayed after-depolarisations, which are thought to underlie the fatal arrhythmia that occurs in both heart failure (HF) and in catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT is an inherited disorder associated with mutations in either the RyR2 or a SR luminal protein, calsequestrin. RyR2 shows normal function at rest in CPVT but the RyR2 dysfunction is unmasked by physical exercise or emotional stress, suggesting abnormal RyR2 activation as an underlying mechanism. Several potential mechanisms have been advanced to explain the dysfunctional RyR2 observed in HF and CPVT, including enhanced RyR2 phosphorylation status, altered RyR2 regulation at luminal/cytoplasmic sites and perturbed RyR2 intra/inter-molecular interactions. This review considers RyR2 dysfunction in the context of the structural and functional modulation of the channel, and potential therapeutic strategies to stabilise RyR2 function in cardiac pathology.
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Affiliation(s)
- Lynda M Blayney
- Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff CF144XN, UK.
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15
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Dulhunty AF, Beard NA, Pouliquin P, Casarotto MG. Agonists and antagonists of the cardiac ryanodine receptor: Potential therapeutic agents? Pharmacol Ther 2007; 113:247-63. [PMID: 17055586 DOI: 10.1016/j.pharmthera.2006.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Accepted: 08/16/2006] [Indexed: 10/24/2022]
Abstract
This review addresses the potential use of the intracellular ryanodine receptor (RyR) Ca(2+) release channel as a therapeutic target in heart disease. Heart disease encompasses a wide range of conditions with the major contributors to mortality and morbidity being ischaemic heart disease and heart failure (HF). In addition there are many rare, but devastating conditions, some of which are either genetically linked to the RyR and its regulatory proteins or involve drug-induced modification of the proteins. The defects in Ca(2+) signalling vary with the nature of the heart disease and the stage in its progress and therefore specific corrections require different modifications of Ca(2+) signalling. Compounds that activate the RyR are potential inotropic agents to increase the Ca(2+) transient and strength of contraction. Compounds that reduce RyR activity are potentially useful in conditions where excess RyR activity initiates arrhythmias, or depletes the Ca(2+) store, as in end stage HF. It has recently been discovered that the cardio-protective action of the drug JTV519 can be attributed partly to its ability to stabilise the interaction between the RyR and the 12.6 kDa binding protein for the commonly used immunosuppressive drug FK506 (FKBP12.6, known as tacrolimus). This has established the credibility of the RyR as a therapeutic target. We explore the possibility that mutations causing the rare RyR-linked arrhythmias will open the door to identification of novel RyR-based therapeutic agents. The use of regulatory binding sites within the RyR complex or on its associated proteins as templates for drug design is discussed.
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Affiliation(s)
- Angela F Dulhunty
- Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, P.O. Box 334, ACT, 2601, Australia
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Abstract
We identified 1113 articles (103 reviews, 1010 primary research articles) published in 2005 that describe experiments performed using commercially available optical biosensors. While this number of publications is impressive, we find that the quality of the biosensor work in these articles is often pretty poor. It is a little disappointing that there appears to be only a small set of researchers who know how to properly perform, analyze, and present biosensor data. To help focus the field, we spotlight work published by 10 research groups that exemplify the quality of data one should expect to see from a biosensor experiment. Also, in an effort to raise awareness of the common problems in the biosensor field, we provide side-by-side examples of good and bad data sets from the 2005 literature.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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