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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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Abstract
The ryanodine receptor/Ca2+ release channel plays a pivotal role in skeletal and cardiac muscle excitation-contraction coupling. Defective regulation leads to neuromuscular disorders and arrhythmogenic cardiac disease. This mini-review focuses on channel regulation through structural intra- and inter-subunit interactions and their implications in ryanodine receptor pathophysiology.
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Functional Impact of Ryanodine Receptor Oxidation on Intracellular Calcium Regulation in the Heart. Rev Physiol Biochem Pharmacol 2016; 171:39-62. [PMID: 27251471 DOI: 10.1007/112_2016_2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Type 2 ryanodine receptor (RyR2) serves as the major intracellular Ca2+ release channel that drives heart contraction. RyR2 is activated by cytosolic Ca2+ via the process of Ca2+-induced Ca2+ release (CICR). To ensure stability of Ca2+ dynamics, the self-reinforcing CICR must be tightly controlled. Defects in this control cause sarcoplasmic reticulum (SR) Ca2+ mishandling, which manifests in a variety of cardiac pathologies that include myocardial infarction and heart failure. These pathologies are also associated with oxidative stress. Given that RyR2 contains a large number of cysteine residues, it is no surprise that RyR2 plays a key role in the cellular response to oxidative stress. RyR's many cysteine residues pose an experimental limitation in defining a specific target or mechanism of action for oxidative stress. As a result, the current understanding of redox-mediated RyR2 dysfunction remains incomplete. Several oxidative modifications, including S-glutathionylation and S-nitrosylation, have been suggested playing an important role in the regulation of RyR2 activity. Moreover, oxidative stress can increase RyR2 activity by forming disulfide bonds between two neighboring subunits (intersubunit cross-linking). Since intersubunit interactions within the RyR2 homotetramer complex dictate the channel gating, such posttranslational modification of RyR2 would have a significant impact on RyR2 function and Ca2+ regulation. This review summarizes recent findings on oxidative modifications of RyR2 and discusses contributions of these RyR2 modifications to SR Ca2+ mishandling during cardiac pathologies.
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54
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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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Xiao Z, Guo W, Yuen SMWK, Wang R, Zhang L, Van Petegem F, Chen SRW. The H29D Mutation Does Not Enhance Cytosolic Ca2+ Activation of the Cardiac Ryanodine Receptor. PLoS One 2015; 10:e0139058. [PMID: 26405799 PMCID: PMC4583508 DOI: 10.1371/journal.pone.0139058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/07/2015] [Indexed: 11/25/2022] Open
Abstract
The N-terminal domain of the cardiac ryanodine receptor (RyR2) harbors a large number of naturally occurring mutations that are associated with stress-induced ventricular tachyarrhythmia and sudden death. Nearly all these disease-associated N-terminal mutations are located at domain interfaces or buried within domains. Mutations at these locations would alter domain-domain interactions or the stability/folding of domains. Recently, a novel RyR2 mutation H29D associated with ventricular arrhythmia at rest was found to enhance the activation of single RyR2 channels by diastolic levels of cytosolic Ca2+. Unlike other N-terminal disease-associated mutations, the H29D mutation is located on the surface of the N-terminal domain. It is unclear how this surface-exposed H29D mutation that does not appear to interact with other parts of the RyR2 structure could alter the intrinsic properties of the channel. Here we carried out detailed functional characterization of the RyR2-H29D mutant at the molecular and cellular levels. We found that the H29D mutation has no effect on the basal level or the Ca2+ dependent activation of [3H]ryanodine binding to RyR2, the cytosolic Ca2+ activation of single RyR2 channels, or the cytosolic Ca2+- or caffeine-induced Ca2+ release in HEK293 cells. In addition, the H29D mutation does not alter the propensity for spontaneous Ca2+ release or the thresholds for Ca2+ release activation or termination. Furthermore, the H29D mutation does not have significant impact on the thermal stability of the N-terminal region (residues 1–547) of RyR2. Collectively, our data show that the H29D mutation exerts little or no effect on the function of RyR2 or on the folding stability of the N-terminal region. Thus, our results provide no evidence that the H29D mutation enhances the cytosolic Ca2+ activation of RyR2.
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Affiliation(s)
- Zhichao Xiao
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Wenting Guo
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Siobhan M. Wong King Yuen
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
| | - Ruiwu Wang
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Lin Zhang
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
| | - S. R. Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- * E-mail:
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56
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Yuchi Z, Yuen SMWK, Lau K, Underhill AQ, Cornea RL, Fessenden JD, Van Petegem F. Crystal structures of ryanodine receptor SPRY1 and tandem-repeat domains reveal a critical FKBP12 binding determinant. Nat Commun 2015; 6:7947. [PMID: 26245150 PMCID: PMC4530471 DOI: 10.1038/ncomms8947] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 06/30/2015] [Indexed: 12/22/2022] Open
Abstract
Ryanodine receptors (RyRs) form calcium release channels located in the membranes of the sarcoplasmic and endoplasmic reticulum. RyRs play a major role in excitation-contraction coupling and other Ca2+-dependent signalling events, and consist of several globular domains that together form a large assembly. Here we describe the crystal structures of the SPRY1 and tandem-repeat domains at 1.2–1.5 Å resolution, which reveal several structural elements not detected in recent cryo-EM reconstructions of RyRs. The cryo-EM studies disagree on the position of SPRY domains, which had been proposed based on homology modelling. Computational docking of the crystal structures, combined with FRET studies, show that the SPRY1 domain is located next to FK506-binding protein (FKBP). Molecular dynamics flexible fitting and mutagenesis experiments suggest a hydrophobic cluster within SPRY1 that is crucial for FKBP binding. A RyR1 disease mutation, N760D, appears to directly impact FKBP binding through interfering with SPRY1 folding. The ryanodine receptor (RyR) is a large multi-domain ion channel that functions to release calcium from the endoplasmic or sarcoplasmic reticulum. Here the authors present crystal structures of the SPRY1 and tandem repeat domains of RyR, allowing precise positioning of the domains and linking disease mutations to RyR function.
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Affiliation(s)
- Zhiguang Yuchi
- Department of Biochemistry and Molecular Biology, The Life Sciences Centre, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
| | - Siobhan M Wong King Yuen
- Department of Biochemistry and Molecular Biology, The Life Sciences Centre, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
| | - Kelvin Lau
- Department of Biochemistry and Molecular Biology, The Life Sciences Centre, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
| | - Ainsley Q Underhill
- Department of Biochemistry and Molecular Biology, The Life Sciences Centre, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 321 Church Street SE, Minneapolis, Minnesota 55455, USA
| | - James D Fessenden
- Department of Anesthesia, Perioperative and Pain Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The Life Sciences Centre, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
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57
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Murayama T, Kurebayashi N, Yamazawa T, Oyamada H, Suzuki J, Kanemaru K, Oguchi K, Iino M, Sakurai T. Divergent Activity Profiles of Type 1 Ryanodine Receptor Channels Carrying Malignant Hyperthermia and Central Core Disease Mutations in the Amino-Terminal Region. PLoS One 2015; 10:e0130606. [PMID: 26115329 PMCID: PMC4482644 DOI: 10.1371/journal.pone.0130606] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 05/21/2015] [Indexed: 11/25/2022] Open
Abstract
The type 1 ryanodine receptor (RyR1) is a Ca2+ release channel in the sarcoplasmic reticulum of skeletal muscle and is mutated in several diseases, including malignant hyperthermia (MH) and central core disease (CCD). Most MH and CCD mutations cause accelerated Ca2+ release, resulting in abnormal Ca2+ homeostasis in skeletal muscle. However, how specific mutations affect the channel to produce different phenotypes is not well understood. In this study, we have investigated 11 mutations at 7 different positions in the amino (N)-terminal region of RyR1 (9 MH and 2 MH/CCD mutations) using a heterologous expression system in HEK293 cells. In live-cell Ca2+ imaging at room temperature (~25 °C), cells expressing mutant channels exhibited alterations in Ca2+ homeostasis, i.e., an enhanced sensitivity to caffeine, a depletion of Ca2+ in the ER and an increase in resting cytoplasmic Ca2+. RyR1 channel activity was quantitatively evaluated by [3H]ryanodine binding and three parameters (sensitivity to activating Ca2+, sensitivity to inactivating Ca2+ and attainable maximum activity, i.e., gain) were obtained by fitting analysis. The mutations increased the gain and the sensitivity to activating Ca2+ in a site-specific manner. The gain was consistently higher in both MH and MH/CCD mutations. Sensitivity to activating Ca2+ was markedly enhanced in MH/CCD mutations. The channel activity estimated from the three parameters provides a reasonable explanation to the pathological phenotype assessed by Ca2+ homeostasis. These properties were also observed at higher temperatures (~37 °C). Our data suggest that divergent activity profiles may cause varied disease phenotypes by specific mutations. This approach should be useful for diagnosis and treatment of diseases with mutations in RyR1.
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Affiliation(s)
- Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo 113–8421, Japan
- * E-mail:
| | - Nagomi Kurebayashi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo 113–8421, Japan
| | - Toshiko Yamazawa
- Department of Molecular Physiology, Jikei University School of Medicine, Tokyo 105–8461, Japan
| | - Hideto Oyamada
- Department of Pharmacology, School of Medicine, Showa University, Tokyo 142–8555, Japan
| | - Junji Suzuki
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo 113–0033, Japan
| | - Kazunori Kanemaru
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo 113–0033, Japan
| | - Katsuji Oguchi
- Department of Pharmacology, School of Medicine, Showa University, Tokyo 142–8555, Japan
| | - Masamitsu Iino
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo 113–0033, Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo 113–8421, Japan
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58
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Liu Y, Sun B, Xiao Z, Wang R, Guo W, Zhang JZ, Mi T, Wang Y, Jones PP, Van Petegem F, Chen SRW. Roles of the NH2-terminal domains of cardiac ryanodine receptor in Ca2+ release activation and termination. J Biol Chem 2015; 290:7736-46. [PMID: 25627681 DOI: 10.1074/jbc.m114.618827] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The NH2-terminal region (residues 1-543) of the cardiac ryanodine receptor (RyR2) harbors a large number of mutations associated with cardiac arrhythmias and cardiomyopathies. Functional studies have revealed that the NH2-terminal region is involved in the activation and termination of Ca(2+) release. The three-dimensional structure of the NH2-terminal region has recently been solved. It is composed of three domains (A, B, and C). However, the roles of these individual domains in Ca(2+) release activation and termination are largely unknown. To understand the functional significance of each of these NH2-terminal domains, we systematically deleted these domains and assessed their impact on caffeine- or Ca(2+)-induced Ca(2+) release and store overload-induced Ca(2+) release (SOICR) in HEK293 cells. We found that all deletion mutants were capable of forming caffeine- and ryanodine-sensitive functional channels, indicating that the NH2-terminal region is not essential for channel gating. Ca(2+) release measurements revealed that deleting domain A markedly reduced the threshold for SOICR termination but had no effect on caffeine or Ca(2+) activation or the threshold for SOICR activation, whereas deleting domain B substantially enhanced caffeine and Ca(2+) activation and lowered the threshold for SOICR activation and termination. Conversely, deleting domain C suppressed caffeine activation, abolished Ca(2+) activation and SOICR, and diminished protein expression. These results suggest that domain A is involved in channel termination, domain B is involved in channel suppression, and domain C is critical for channel activation and expression. Our data shed new insights into the structure-function relationship of the NH2-terminal domains of RyR2 and the action of NH2-terminal disease mutations.
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Affiliation(s)
- 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
| | - 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
| | - 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
| | - 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
| | - Joe Z Zhang
- Department of Physiology and HeartOtago, University of Otago, Dunedin 9054, New Zealand, and
| | - Tao Mi
- 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
| | - Peter P Jones
- Department of Physiology and HeartOtago, University of Otago, Dunedin 9054, New Zealand, and
| | - Filip Van Petegem
- Cardiovascular Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, 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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59
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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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60
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Seo MD, Enomoto M, Ishiyama N, Stathopulos PB, Ikura M. Structural insights into endoplasmic reticulum stored calcium regulation by inositol 1,4,5-trisphosphate and ryanodine receptors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1980-91. [PMID: 25461839 DOI: 10.1016/j.bbamcr.2014.11.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 11/17/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
Abstract
The two major calcium (Ca²⁺) release channels on the sarco/endoplasmic reticulum (SR/ER) are inositol 1,4,5-trisphosphate and ryanodine receptors (IP3Rs and RyRs). They play versatile roles in essential cell signaling processes, and abnormalities of these channels are associated with a variety of diseases. Structural information on IP3Rs and RyRs determined using multiple techniques including X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy and cryo-electron microscopy (EM), has significantly advanced our understanding of the mechanisms by which these Ca²⁺ release channels function under normal and pathophysiological circumstances. In this review, structural advances on the understanding of the mechanisms of IP3R and RyR function and dysfunction are summarized. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
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Affiliation(s)
- Min-Duk Seo
- Department of Molecular Science and Technology, Ajou University, Suwon, Gyeonggi 443-749, Republic of Korea; College of Pharmacy, Ajou University, Suwon, Gyeonggi 443-749, Republic of Korea
| | - Masahiro Enomoto
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Noboru Ishiyama
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada.
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61
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Seidel M, Thomas NL, Williams AJ, Lai FA, Zissimopoulos S. Dantrolene rescues aberrant N-terminus intersubunit interactions in mutant pro-arrhythmic cardiac ryanodine receptors. Cardiovasc Res 2014; 105:118-28. [PMID: 25411383 DOI: 10.1093/cvr/cvu240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS The ryanodine receptor (RyR2) is an intracellular Ca(2+) release channel essential for cardiac excitation-contraction coupling. Abnormal RyR2 channel function results in the generation of arrhythmias and sudden cardiac death. The present study was undertaken to investigate the mechanistic basis of RyR2 dysfunction in inherited arrhythmogenic cardiac disease. METHODS AND RESULTS We present several lines of complementary evidence, indicating that the arrhythmia-associated L433P mutation disrupts RyR2 N-terminus self-association. A combination of yeast two-hybrid, co-immunoprecipitation, and chemical cross-linking assays collectively demonstrate that a RyR2 N-terminal fragment carrying the L433P mutation displays substantially reduced self-interaction compared with wild type. Moreover, sucrose density gradient centrifugation reveals that the L433P mutation impairs tetramerization of the full-length channel. [(3)H]Ryanodine-binding assays demonstrate that disrupted N-terminal intersubunit interactions within RyR2(L433P) confer an altered sensitivity to Ca(2+) activation. Calcium imaging of RyR2(L433P)-expressing cells reveals substantially prolonged Ca(2+) transients and reduced Ca(2+) store content indicating defective channel closure. Importantly, dantrolene treatment reverses the L433P mutation-induced impairment and restores channel function. CONCLUSION The N-terminus domain constitutes an important structural determinant for the functional oligomerization of RyR2. Our findings are consistent with defective N-terminus self-association as a molecular mechanism underlying RyR2 channel deregulation in inherited arrhythmogenic cardiac disease. Significantly, the therapeutic action of dantrolene may occur via the restoration of normal RyR2 N-terminal intersubunit interactions.
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Affiliation(s)
- Monika Seidel
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - N Lowri Thomas
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - Alan J Williams
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - F Anthony Lai
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - Spyros Zissimopoulos
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
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62
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Gillespie D, Xu L, Meissner G. Selecting ions by size in a calcium channel: the ryanodine receptor case study. Biophys J 2014; 107:2263-73. [PMID: 25418295 PMCID: PMC4241444 DOI: 10.1016/j.bpj.2014.09.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 09/25/2014] [Accepted: 09/30/2014] [Indexed: 10/24/2022] Open
Abstract
Many calcium channels can distinguish between ions of the same charge but different size. For example, when cations are in direct competition with each other, the ryanodine receptor (RyR) calcium channel preferentially conducts smaller cations such as Li(+) and Na(+) over larger ones such as K(+) and Cs(+). Here, we analyze the physical basis for this preference using a previously established model of RyR permeation and selectivity. Like other calcium channels, RyR has four aspartate residues in its GGGIGDE selectivity filter. These aspartates have their terminal carboxyl group in the pore lumen, which take up much of the available space for permeating ions. We find that small ions are preferred by RyR because they can fit into this crowded environment more easily.
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Affiliation(s)
- Dirk Gillespie
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois.
| | - Le Xu
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina
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63
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Lau K, Van Petegem F. Crystal structures of wild type and disease mutant forms of the ryanodine receptor SPRY2 domain. Nat Commun 2014; 5:5397. [DOI: 10.1038/ncomms6397] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 09/26/2014] [Indexed: 12/16/2022] Open
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64
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Borko Ľ, Bauerová-Hlinková V, Hostinová E, Gašperík J, Beck K, Lai FA, Zahradníková A, Ševčík J. Structural insights into the human RyR2 N-terminal region involved in cardiac arrhythmias. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:2897-912. [PMID: 25372681 PMCID: PMC4220973 DOI: 10.1107/s1399004714020343] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 09/10/2014] [Indexed: 01/11/2023]
Abstract
Human ryanodine receptor 2 (hRyR2) mediates calcium release from the sarcoplasmic reticulum, enabling cardiomyocyte contraction. The N-terminal region of hRyR2 (amino acids 1-606) is the target of >30 arrhythmogenic mutations and contains a binding site for phosphoprotein phosphatase 1. Here, the solution and crystal structures determined under near-physiological conditions, as well as a homology model of the hRyR2 N-terminal region, are presented. The N-terminus is held together by a unique network of interactions among its three domains, A, B and C, in which the central helix (amino acids 410-437) plays a prominent stabilizing role. Importantly, the anion-binding site reported for the mouse RyR2 N-terminal region is notably absent from the human RyR2. The structure concurs with the differential stability of arrhythmogenic mutations in the central helix (R420W, I419F and I419F/R420W) which are owing to disparities in the propensity of mutated residues to form energetically favourable or unfavourable contacts. In solution, the N-terminus adopts a globular shape with a prominent tail that is likely to involve residues 545-606, which are unresolved in the crystal structure. Docking the N-terminal domains into cryo-electron microscopy maps of the closed and open RyR1 conformations reveals C(α) atom movements of up to 8 Å upon channel gating, and predicts the location of the leucine-isoleucine zipper segment and the interaction site for spinophilin and phosphoprotein phosphatase 1 on the RyR surface.
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Affiliation(s)
- Ľubomír Borko
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Vladena Bauerová-Hlinková
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Eva Hostinová
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Juraj Gašperík
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Konrad Beck
- Cardiff University School of Dentistry, Heath Park, Cardiff CF14 4XY, Wales
| | - F. Anthony Lai
- Department of Cardiology, Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff CF14 4XN, Wales
| | - Alexandra Zahradníková
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, 833 34 Bratislava, Slovakia
| | - Jozef Ševčík
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
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Abstract
In the 30 years since IP3 (inositol 1,4,5-trisphosphate) was first shown to release Ca2+ from intracellular stores, the importance of spatially organized interactions within IP3-regulated signalling pathways has been universally recognized. Recent evidence that addresses three different levels of the structural determinants of IP3-evoked Ca2+ signalling is described in the present review. High-resolution structures of the N-terminal region of the IP3R (IP3 receptor) have established that the two essential phosphate groups of IP3 bind to opposite sides of the IP3-binding site, pulling its two domains together. This conformational change is proposed to disrupt an interaction between adjacent subunits within the tetrameric IP3R that normally holds the channel in a closed state. Similar structural changes are thought to allow gating of ryanodine receptors. cAMP increases the sensitivity of IP3Rs and thereby potentiates the Ca2+ signals evoked by receptors that stimulate IP3 formation. We speculate that both IP3 and cAMP are delivered to IP3Rs within signalling junctions, wherein the associated IP3Rs are exposed to a saturating concentration of either messenger. The concentration-dependent effects of extracellular stimuli come from recruitment of junctions rather than from a graded increase in the activity of individual junctions. IP3Rs within 'IP3 junctions' respond directly to receptors that stimulate phospholipase C, whereas extra-junctional IP3Rs are exposed to suboptimal concentrations of IP3 and open only when they are sensitized by cAMP. These results highlight the importance of selective delivery of diffusible messengers to IP3Rs. The spatial organization of IP3Rs also allows them to direct Ca2+ to specific intracellular targets that include other IP3Rs, mitochondria and Ca2+-regulated channels and enzymes. IP3Rs also interact functionally with lysosomes because Ca2+ released by IP3Rs, but not that entering cells via store-operated Ca2+ entry pathways, is selectively accumulated by lysosomes. This Ca2+ uptake shapes the Ca2+ signals evoked by IP3 and it may regulate lysosomal behaviour.
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66
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Lau K, Chan MMY, Van Petegem F. Lobe-specific calmodulin binding to different ryanodine receptor isoforms. Biochemistry 2014; 53:932-46. [PMID: 24447242 DOI: 10.1021/bi401502x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Ryanodine receptors (RyRs) are large ion channels that are responsible for the release of Ca(2+) from the sarcoplasmic/endoplasmic reticulum. Calmodulin (CaM) is a Ca(2+) binding protein that can affect the channel open probability at both high and low Ca(2+) concentrations, shifting the Ca(2+) dependencies of channel opening in an isoform-specific manner. Here we analyze the binding of CaM and its individual domains to three different RyR regions using isothermal titration calorimetry. We compared binding to skeletal muscle (RyR1) and cardiac (RyR2) isoforms, under both Ca(2+)-loaded and Ca(2+)-free conditions. CaM can bind all three regions in both isoforms, but the binding modes differ appreciably in two segments. The results highlight a Ca(2+)/CaM and apoCaM binding site in the C-terminal fifth of the channel. This binding site is the target for malignant hyperthermia and central core disease mutations in RyR1, which affect the energetics and mode of CaM binding.
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Affiliation(s)
- Kelvin Lau
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia , Vancouver, British Columbia V6T 1Z3, Canada
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67
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Zhong X, Liu Y, Zhu L, Meng X, Wang R, Van Petegem F, Wagenknecht T, Chen SRW, Liu Z. Conformational dynamics inside amino-terminal disease hotspot of ryanodine receptor. Structure 2013; 21:2051-60. [PMID: 24139989 DOI: 10.1016/j.str.2013.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 08/22/2013] [Accepted: 09/11/2013] [Indexed: 11/15/2022]
Abstract
The N-terminal region of both skeletal and cardiac ryanodine receptor is a disease mutation hotspot. Recently, a crystal structure of the RyR1 fragment (residues 1-559) was solved. This N-terminal structure contains three separate domains, A, B, and C, and was docked into a central vestibule in a full-length RyR1 cryo-EM map. Here, we reconstructed three-dimensional cryo-EM structures of two GFP-tagged RyR2s with GFP inserted after residue Glu-310 and Ser-437, respectively. The structures of RyR2E310-GFP and RyR2S437-GFP displayed an extra mass on domain B and C, directly validating the predicted docking model. Next, we revealed domain movements in molecular dynamics flexible fitting models in both the closed and open state cryo-EM maps. To further probe the conformational changes, we generated FRET pairs by inserting CFP or YFP in two selected domains, FRET studies of three dual-insertion pairs and three co-expressed single-insertion pairs showed the dynamic structural changes within the N-terminal domains.
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Affiliation(s)
- Xiaowei Zhong
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
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68
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Amador FJ, Kimlicka L, Stathopulos PB, Gasmi-Seabrook GMC, Maclennan DH, Van Petegem F, Ikura M. Type 2 ryanodine receptor domain A contains a unique and dynamic α-helix that transitions to a β-strand in a mutant linked with a heritable cardiomyopathy. J Mol Biol 2013; 425:4034-46. [PMID: 23978697 DOI: 10.1016/j.jmb.2013.08.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/09/2013] [Accepted: 08/19/2013] [Indexed: 11/18/2022]
Abstract
Ryanodine receptors (RyRs) are large tetrameric calcium (Ca(2+)) release channels found on the sarcoplasmic reticulum that respond to dihydropyridine receptor activity through a direct conformational interaction and/or indirect Ca(2+) sensitivity, propagating sarcoplasmic reticulum luminal Ca(2+) release in the process of excitation-contraction coupling. There are three human RyR subtypes, and several debilitating diseases are linked to heritable mutations in RyR1 and RyR2 including malignant hypothermia, central core disease, catecholaminergic polymorphic ventricular tachycardia (CPVT) and arrhythmogenic right ventricular dysplasia type 2 (ARVD2). Despite the recent appreciation that many disease-associated mutations within the N-terminal RyRABC domains (i.e., residues 1-559) are located in the putative interfaces mediating tetrameric channel assembly, the precise structural and dynamical consequences of the mutations are not well understood. We used solution nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography to examine the effect of ARVD2-associated (i.e., R176Q) and CPVT-associated [i.e., P164S, R169Q and delta exon 3 (Δ3)] mutations on the structure and dynamics of RyR2A. Our solution NMR data exposed a mobile α-helix, unique to type 2; further, this α2 helix rescues the β-strand lost in RyR2A Δ3 but remains dynamic in the hot-spot loop (HS-loop) P164S, R169Q and R176Q mutant proteins. Docking of our X-ray crystal/NMR hybrid structure into the RyR1 cryo-electron microscopy map revealed that this RyR2A α2 helix is in close proximity to dense "columns" projecting toward the channel pore. This is in contrast to the HS-loop mutations that cause structural changes largely localized to the intersubunit interface between adjacent ABC domains. Taken together, our data suggest that ARVD2 and CPVT mutations have at least two distinct structural consequences linked to channel dysfunction: perturbation of the HS-loop (i.e., domain A):domain B intersubunit interface and disruption of the communication between the N-terminal region and the channel domain.
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Affiliation(s)
- Fernando J Amador
- Campbell Family Institute for Cancer Research, Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 1L7
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69
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The CPVT-associated RyR2 mutation G230C enhances store overloadinduced Ca2+ release and destabilizes the N-terminal domains. Biochem J 2013; 454:123-31. [DOI: 10.1042/bj20130594] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
CPVT (catecholaminergic polymorphic ventricular tachycardia) is an inherited life-threatening arrhythmogenic disorder. CPVT is caused by DADs (delayed after-depolarizations) that are induced by spontaneous Ca2+ release during SR (sarcoplasmic reticulum) Ca2+ overload, a process also known as SOICR (store-overload-induced Ca2+ release). A number of mutations in the cardiac ryanodine receptor RyR2 are linked to CPVT. Many of these CPVT-associated RyR2 mutations enhance the propensity for SOICR and DADs by sensitizing RyR2 to luminal or luminal/cytosolic Ca2+ activation. Recently, a novel CPVT RyR2 mutation, G230C, was found to increase the cytosolic, but not the luminal, Ca2+ sensitivity of single RyR2 channels in lipid bilayers. This observation led to the suggestion of a SOICR-independent disease mechanism for the G230C mutation. However, the cellular impact of this mutation on SOICR is yet to be determined. To this end, we generated stable inducible HEK (human embryonic kidney)-293 cell lines expressing the RyR2 WT (wild-type) and the G230C mutant. Using single-cell Ca2+ imaging, we found that the G230C mutation markedly enhanced the propensity for SOICR and reduced the SOICR threshold. Furthermore, the G230C mutation increased the sensitivity of single RyR2 channels to both luminal and cytosolic Ca2+ activation and the Ca2+-dependent activation of [3H]ryanodine binding. In addition, the G230C mutation decreased the thermal stability of the N-terminal region (amino acids 1–547) of RyR2. These data suggest that the G230C mutation enhances the propensity for SOICR by sensitizing the channel to luminal and cytosolic Ca2+ activation, and that G230C has an intrinsic structural impact on the N-terminal domains of RyR2.
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70
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Kimlicka L, Tung CC, Carlsson ACC, Lobo PA, Yuchi Z, Van Petegem F. The cardiac ryanodine receptor N-terminal region contains an anion binding site that is targeted by disease mutations. Structure 2013; 21:1440-9. [PMID: 23871484 DOI: 10.1016/j.str.2013.06.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 06/10/2013] [Accepted: 06/13/2013] [Indexed: 11/30/2022]
Abstract
Ryanodine receptors (RyRs) are calcium release channels located in the membrane of the endoplasmic and sarcoplasmic reticulum and play a major role in muscle excitation-contraction coupling. The cardiac isoform (RyR2) is the target for >150 mutations that cause catecholaminergic polymorphic ventricular tachycardia (CPVT) and other conditions. Here, we present the crystal structure of the N-terminal region of RyR2 (1-547), an area encompassing 29 distinct disease mutations. The protein folds up in three individual domains, which are held together via a central chloride anion that shields repulsive positive charges. Several disease mutant versions of the construct drastically destabilize the protein. The R420Q disease mutant causes CPVT and ablates chloride binding. The mutation results in reorientations of the first two domains relative to the third domain. These conformational changes likely activate the channel by destabilizing intersubunit interactions that are disrupted upon channel opening.
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Affiliation(s)
- Lynn Kimlicka
- Department of Biochemistry and Molecular Biology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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