1
|
Sun QA, Grimmett ZW, Hess DT, Perez LG, Qian Z, Chaube R, Venetos NM, Plummer BN, Laurita KR, Premont RT, Stamler JS. Physiological role for S-nitrosylation of RyR1 in skeletal muscle function and development. Biochem Biophys Res Commun 2024; 723:150163. [PMID: 38820626 DOI: 10.1016/j.bbrc.2024.150163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/20/2024] [Accepted: 05/22/2024] [Indexed: 06/02/2024]
Abstract
Excitation-contraction coupling in skeletal muscle myofibers depends upon Ca2+ release from the sarcoplasmic reticulum through the ryanodine receptor/Ca2+-release channel RyR1. The RyR1 contains ∼100 Cys thiols of which ∼30 comprise an allosteric network subject to posttranslational modification by S-nitrosylation, S-palmitoylation and S-oxidation. However, the role and function of these modifications is not understood. Although aberrant S-nitrosylation of multiple unidentified sites has been associated with dystrophic diseases, malignant hyperthermia and other myopathic syndromes, S-nitrosylation in physiological situations is reportedly specific to a single (1 of ∼100) Cys in RyR1, Cys3636 in a manner gated by pO2. Using mice expressing a form of RyR1 with a Cys3636→Ala point mutation to prevent S-nitrosylation at this site, we showed that Cys3636 was the principal target of endogenous S-nitrosylation during normal muscle function. The absence of Cys3636 S-nitrosylation suppressed stimulus-evoked Ca2+ release at physiological pO2 (at least in part by altering the regulation of RyR1 by Ca2+/calmodulin), eliminated pO2 coupling, and diminished skeletal myocyte contractility in vitro and measures of muscle strength in vivo. Furthermore, we found that abrogation of Cys3636 S-nitrosylation resulted in a developmental defect reflected in diminished myofiber diameter, altered fiber subtypes, and altered expression of genes implicated in muscle development and atrophy. Thus, our findings establish a physiological role for pO2-coupled S-nitrosylation of RyR1 in skeletal muscle contractility and development and provide foundation for future studies of RyR1 modifications in physiology and disease.
Collapse
Affiliation(s)
- Qi-An Sun
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Zachary W Grimmett
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Douglas T Hess
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Lautaro G Perez
- Department of Surgery, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Zhaoxia Qian
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Ruchi Chaube
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Nicholas M Venetos
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Bradley N Plummer
- Heart and Vascular Research Center, MetroHealth Campus of Case Western Reserve University, Cleveland, OH, 44109, USA
| | - Kenneth R Laurita
- Heart and Vascular Research Center, MetroHealth Campus of Case Western Reserve University, Cleveland, OH, 44109, USA
| | - Richard T Premont
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA; Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Jonathan S Stamler
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA; Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA.
| |
Collapse
|
2
|
Weninger G, Miotto MC, Tchagou C, Reiken S, Dridi H, Brandenburg S, Riedemann GC, Yuan Q, Liu Y, Chang A, Wronska A, Lehnart SE, Marks AR. Structural insights into the regulation of RyR1 by S100A1. Proc Natl Acad Sci U S A 2024; 121:e2400497121. [PMID: 38917010 DOI: 10.1073/pnas.2400497121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 05/23/2024] [Indexed: 06/27/2024] Open
Abstract
S100A1, a small homodimeric EF-hand Ca2+-binding protein (~21 kDa), plays an important regulatory role in Ca2+ signaling pathways involved in various biological functions including Ca2+ cycling and contractile performance in skeletal and cardiac myocytes. One key target of the S100A1 interactome is the ryanodine receptor (RyR), a huge homotetrameric Ca2+ release channel (~2.3 MDa) of the sarcoplasmic reticulum. Here, we report cryoelectron microscopy structures of S100A1 bound to RyR1, the skeletal muscle isoform, in absence and presence of Ca2+. Ca2+-free apo-S100A1 binds beneath the bridging solenoid (BSol) and forms contacts with the junctional solenoid and the shell-core linker of RyR1. Upon Ca2+-binding, S100A1 undergoes a conformational change resulting in the exposure of the hydrophobic pocket known to serve as a major interaction site of S100A1. Through interactions of the hydrophobic pocket with RyR1, Ca2+-bound S100A1 intrudes deeper into the RyR1 structure beneath BSol than the apo-form and induces sideways motions of the C-terminal BSol region toward the adjacent RyR1 protomer resulting in tighter interprotomer contacts. Interestingly, the second hydrophobic pocket of the S100A1-dimer is largely exposed at the hydrophilic surface making it prone to interactions with the local environment, suggesting that S100A1 could be involved in forming larger heterocomplexes of RyRs with other protein partners. Since S100A1 interactions stabilizing BSol are implicated in the regulation of RyR-mediated Ca2+ release, the characterization of the S100A1 binding site conserved between RyR isoforms may provide the structural basis for the development of therapeutic strategies regarding treatments of RyR-related disorders.
Collapse
Affiliation(s)
- Gunnar Weninger
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Marco C Miotto
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Carl Tchagou
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Steven Reiken
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Haikel Dridi
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Sören Brandenburg
- Department of Cardiology and Pneumology, Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC 2067), University of Göttingen, 37075 Göttingen, Germany
| | - Gabriel C Riedemann
- Department of Cardiology and Pneumology, Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Qi Yuan
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Yang Liu
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Alexander Chang
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Anetta Wronska
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| | - Stephan E Lehnart
- Department of Cardiology and Pneumology, Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, 37075 Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC 2067), University of Göttingen, 37075 Göttingen, Germany
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032
| |
Collapse
|
3
|
Hu M, Feng X, Liu Q, Liu S, Huang F, Xu H. The ion channels of endomembranes. Physiol Rev 2024; 104:1335-1385. [PMID: 38451235 DOI: 10.1152/physrev.00025.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 02/20/2024] [Accepted: 02/25/2024] [Indexed: 03/08/2024] Open
Abstract
The endomembrane system consists of organellar membranes in the biosynthetic pathway [endoplasmic reticulum (ER), Golgi apparatus, and secretory vesicles] as well as those in the degradative pathway (early endosomes, macropinosomes, phagosomes, autophagosomes, late endosomes, and lysosomes). These endomembrane organelles/vesicles work together to synthesize, modify, package, transport, and degrade proteins, carbohydrates, and lipids, regulating the balance between cellular anabolism and catabolism. Large ion concentration gradients exist across endomembranes: Ca2+ gradients for most endomembrane organelles and H+ gradients for the acidic compartments. Ion (Na+, K+, H+, Ca2+, and Cl-) channels on the organellar membranes control ion flux in response to cellular cues, allowing rapid informational exchange between the cytosol and organelle lumen. Recent advances in organelle proteomics, organellar electrophysiology, and luminal and juxtaorganellar ion imaging have led to molecular identification and functional characterization of about two dozen endomembrane ion channels. For example, whereas IP3R1-3 channels mediate Ca2+ release from the ER in response to neurotransmitter and hormone stimulation, TRPML1-3 and TMEM175 channels mediate lysosomal Ca2+ and H+ release, respectively, in response to nutritional and trafficking cues. This review aims to summarize the current understanding of these endomembrane channels, with a focus on their subcellular localizations, ion permeation properties, gating mechanisms, cell biological functions, and disease relevance.
Collapse
Affiliation(s)
- Meiqin Hu
- Department of Neurology and Department of Cardiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People's Republic of China
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Xinghua Feng
- Department of Neurology and Department of Cardiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People's Republic of China
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Qiang Liu
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Siyu Liu
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Fangqian Huang
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Haoxing Xu
- Department of Neurology and Department of Cardiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People's Republic of China
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States
| |
Collapse
|
4
|
Fernández-Morales JC, Toth N, Bayram P, Rienzo T, Morad M. Loss-of-function W4645R mutation in the RyR2-caffeine binding site: implications for synchrony and arrhythmogenesis. Cell Calcium 2024; 123:102925. [PMID: 38908063 DOI: 10.1016/j.ceca.2024.102925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 06/14/2024] [Accepted: 06/16/2024] [Indexed: 06/24/2024]
Abstract
AIMS Previous studies have identified RyR2 W4645R mutation, located in the caffeine-binding site, to associate with CPVT1 pathology. Caffeine binding to its site is thought to displace the carboxyl-terminal domain to Ca2+-binding, allowing the tryptophan residue (W4645) to regulate Ca2+ sensitivity of RyR2. To gain insights into regulation of RyR2 Ca2+-binding and its interaction with caffeine-binding site, we introduced W4645R-RyR2 point mutation via CRISPR/Cas9 gene-editing in human induced pluripotent stem cell-derived cardiomyocytes (hiPSCCMs) and characterized their Ca2+-signaling phenotype compared to WT hiPSCCMs. METHODS AND RESULTS W4645R-RyR2 cardiomyocytes had: (1) no significant change in ICa magnitude or voltage-dependence; (2) slightly reduced CICR; (3) altered relaxation kinetics of Ca2+-transients with no change in isoproterenol sensitivity; (4) complete loss of caffeine-triggered Ca2+ release; (5) larger SR Ca2+ leak resulting in 40 % lower SR Ca2+ content, as determined by myocytes' response to 4-CmC; (6) lower incidence of calcium sparks and asynchronous spontaneous SR Ca2+ releases. CONCLUSIONS W4645R-RyR2 mutation induces loss of caffeine-triggered SR Ca2+ release and enhances SR Ca2+ leak that underlie asynchronous spontaneous Ca2+ releases, triggering arrhythmia and impairing cardiac function.
Collapse
Affiliation(s)
| | - Noemi Toth
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Pinar Bayram
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Taylor Rienzo
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Martin Morad
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA; Department of Regenerative Medicine and Cell Biology, MUSC,Charleston, SC, USA.
| |
Collapse
|
5
|
Rebbeck RT, Svensson B, Zhang J, Samsó M, Thomas DD, Bers DM, Cornea RL. Kinetics and mapping of Ca-driven calmodulin conformations on skeletal and cardiac muscle ryanodine receptors. Nat Commun 2024; 15:5120. [PMID: 38879623 PMCID: PMC11180167 DOI: 10.1038/s41467-024-48951-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 05/16/2024] [Indexed: 06/19/2024] Open
Abstract
Calmodulin transduces [Ca2+] information regulating the rhythmic Ca2+ cycling between the sarcoplasmic reticulum and cytoplasm during contraction and relaxation in cardiac and skeletal muscle. However, the structural dynamics by which calmodulin modulates the sarcoplasmic reticulum Ca2+ release channel, the ryanodine receptor, at physiologically relevant [Ca2+] is unknown. Using fluorescence lifetime FRET, we resolve different structural states of calmodulin and Ca2+-driven shifts in the conformation of calmodulin bound to ryanodine receptor. Skeletal and cardiac ryanodine receptor isoforms show different calmodulin-ryanodine receptor conformations, as well as binding and structural kinetics with 0.2-ms resolution, which reflect different functional roles of calmodulin. These FRET methods provide insight into the physiological calmodulin-ryanodine receptor structural states, revealing additional distinct structural states that complement cryo-EM models that are based on less physiological conditions. This technology will drive future studies on pathological calmodulin-ryanodine receptor interactions and dynamics with other important ryanodine receptor bound modulators.
Collapse
Affiliation(s)
- Robyn T Rebbeck
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis, MN, USA.
| | - Bengt Svensson
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Jingyan Zhang
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Montserrat Samsó
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Donald M Bers
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis, MN, USA.
| |
Collapse
|
6
|
Taweechat P, Boonamnaj P, Samsó M, Sompornpisut P. Significance of Zn 2+ in RyR1 for Structural Integrity and Ligand Binding: Insight from Molecular Dynamics. J Phys Chem B 2024; 128:4670-4684. [PMID: 38717304 PMCID: PMC11103704 DOI: 10.1021/acs.jpcb.4c01189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/24/2024] [Accepted: 04/24/2024] [Indexed: 05/22/2024]
Abstract
Ryanodine receptor type 1 (RyR1) is a Ca2+-release channel central to skeletal muscle excitation-contraction (EC) coupling. RyR1's cryo-EM structures reveal a zinc-finger motif positioned within the cytoplasmic C-terminal domain (CTD). Yet, owing to limitations in cryo-EM resolution, RyR1 structures lack precision in detailing the metal coordination structure, prompting the need for an accurate model. In this study, we employed molecular dynamics (MD) simulations and the density functional theory (DFT) method to refine the binding characteristics of Zn2+ in the zinc-finger site of the RyR1 channel. Our findings also highlight substantial conformational changes in simulations conducted in the absence of Zn2+. Notably, we observed a loss of contact at the interface between protein domains proximal to the zinc-finger site, indicating a crucial role of Zn2+ in maintaining structural integrity and interdomain interactions within RyR1. Furthermore, this study provides valuable insights into the modulation of ATP, Ca2+, and caffeine binding, shedding light on the intricate relationship between Zn2+ coordination and the dynamic behavior of RyR1. Our integrative approach combining MD simulations and DFT calculations enhances our understanding of the molecular mechanisms governing ligand binding in RyR1.
Collapse
Affiliation(s)
- Panyakorn Taweechat
- Center
of Excellence in Computational Chemistry, Department of Chemistry,
Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Panisak Boonamnaj
- Center
of Excellence in Computational Chemistry, Department of Chemistry,
Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Montserrat Samsó
- Department
of Physiology and Biophysics, Virginia Commonwealth
University, Richmond, Virginia 23298, United States
| | - Pornthep Sompornpisut
- Center
of Excellence in Computational Chemistry, Department of Chemistry,
Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| |
Collapse
|
7
|
Nayak AR, Rangubpit W, Will AH, Hu Y, Castro-Hartmann P, Lobo JJ, Dryden K, Lamb GD, Sompornpisut P, Samsó M. Interplay between Mg 2+ and Ca 2+ at multiple sites of the ryanodine receptor. Nat Commun 2024; 15:4115. [PMID: 38750013 PMCID: PMC11096358 DOI: 10.1038/s41467-024-48292-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 04/26/2024] [Indexed: 05/18/2024] Open
Abstract
RyR1 is an intracellular Ca2+ channel important in excitable cells such as neurons and muscle fibers. Ca2+ activates it at low concentrations and inhibits it at high concentrations. Mg2+ is the main physiological RyR1 inhibitor, an effect that is overridden upon activation. Despite the significance of Mg2+-mediated inhibition, the molecular-level mechanisms remain unclear. In this work we determined two cryo-EM structures of RyR1 with Mg2+ up to 2.8 Å resolution, identifying multiple Mg2+ binding sites. Mg2+ inhibits at the known Ca2+ activating site and we propose that the EF hand domain is an inhibitory divalent cation sensor. Both divalent cations bind to ATP within a crevice, contributing to the precise transmission of allosteric changes within the enormous channel protein. Notably, Mg2+ inhibits RyR1 by interacting with the gating helices as validated by molecular dynamics. This structural insight enhances our understanding of how Mg2+ inhibition is overcome during excitation.
Collapse
Affiliation(s)
- Ashok R Nayak
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Warin Rangubpit
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Alex H Will
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Yifan Hu
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Pablo Castro-Hartmann
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
- ThermoFisher Scientific, Cambridge, UK
| | - Joshua J Lobo
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Kelly Dryden
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
- Department of Chemistry and Biochemistry, UC Santa Barbara, Santa Barbara, CA, USA
| | - Graham D Lamb
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC, Australia
| | - Pornthep Sompornpisut
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.
| | - Montserrat Samsó
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA.
| |
Collapse
|
8
|
Benucci S, Ruiz A, Franchini M, Ruggiero L, Zoppi D, Sitsapesan R, Lindsay C, Pelczar P, Pietrangelo L, Protasi F, Treves S, Zorzato F. A novel, patient-derived RyR1 mutation impairs muscle function and calcium homeostasis in mice. J Gen Physiol 2024; 156:e202313486. [PMID: 38445312 PMCID: PMC10911087 DOI: 10.1085/jgp.202313486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/20/2023] [Accepted: 02/09/2024] [Indexed: 03/07/2024] Open
Abstract
RYR1 is the most commonly mutated gene associated with congenital myopathies, a group of early-onset neuromuscular conditions of variable severity. The functional effects of a number of dominant RYR1 mutations have been established; however, for recessive mutations, these effects may depend on multiple factors, such as the formation of a hypomorphic allele, or on whether they are homozygous or compound heterozygous. Here, we functionally characterize a new transgenic mouse model knocked-in for mutations identified in a severely affected child born preterm and presenting limited limb movement. The child carried the homozygous c.14928C>G RYR1 mutation, resulting in the p.F4976L substitution. In vivo and ex vivo assays revealed that homozygous mice fatigued sooner and their muscles generated significantly less force compared with their WT or heterozygous littermates. Electron microscopy, biochemical, and physiological analyses showed that muscles from RyR1 p.F4976L homozygous mice have the following properties: (1) contain fewer calcium release units and show areas of myofibrillar degeneration, (2) contain less RyR1 protein, (3) fibers show smaller electrically evoked calcium transients, and (4) their SR has smaller calcium stores. In addition, single-channel recordings indicate that RyR1 p.F4976L exhibits higher Po in the presence of 100 μM [Ca2+]. Our mouse model partly recapitulates the clinical picture of the homozygous human patient and provides significant insight into the functional impact of this mutation. These results will help understand the pathology of patients with similar RYR1 mutations.
Collapse
Affiliation(s)
- Sofia Benucci
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Alexis Ruiz
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Martina Franchini
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Lucia Ruggiero
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli Federico II, Napoli, Italy
| | - Dario Zoppi
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli Federico II, Napoli, Italy
| | | | - Chris Lindsay
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Pawel Pelczar
- Center for Transgenic Models, University of Basel, Basel, Switzerland
| | - Laura Pietrangelo
- DMSI, Department of Medicine and Aging Sciences and CAST, Center for Advanced Studies and Technology, University G. d’Annunzio of Chieti-Pescara, Chieti, Italy
| | - Feliciano Protasi
- DMSI, Department of Medicine and Aging Sciences and CAST, Center for Advanced Studies and Technology, University G. d’Annunzio of Chieti-Pescara, Chieti, Italy
| | - Susan Treves
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
- Department of Life Science and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Francesco Zorzato
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
- Department of Life Science and Biotechnology, University of Ferrara, Ferrara, Italy
| |
Collapse
|
9
|
Xu J, Liao C, Yin CC, Li G, Zhu Y, Sun F. In situ structural insights into the excitation-contraction coupling mechanism of skeletal muscle. SCIENCE ADVANCES 2024; 10:eadl1126. [PMID: 38507485 PMCID: PMC10954225 DOI: 10.1126/sciadv.adl1126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 02/12/2024] [Indexed: 03/22/2024]
Abstract
Excitation-contraction coupling (ECC) is a fundamental mechanism in control of skeletal muscle contraction and occurs at triad junctions, where dihydropyridine receptors (DHPRs) on transverse tubules sense excitation signals and then cause calcium release from the sarcoplasmic reticulum via coupling to type 1 ryanodine receptors (RyR1s), inducing the subsequent contraction of muscle filaments. However, the molecular mechanism remains unclear due to the lack of structural details. Here, we explored the architecture of triad junction by cryo-electron tomography, solved the in situ structure of RyR1 in complex with FKBP12 and calmodulin with the resolution of 16.7 Angstrom, and found the intact RyR1-DHPR supercomplex. RyR1s arrange into two rows on the terminal cisternae membrane by forming right-hand corner-to-corner contacts, and tetrads of DHPRs bind to RyR1s in an alternating manner, forming another two rows on the transverse tubule membrane. This unique arrangement is important for synergistic calcium release and provides direct evidence of physical coupling in ECC.
Collapse
Affiliation(s)
- Jiashu Xu
- Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chenyi Liao
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Chang-Cheng Yin
- Department of Biophysics, The Health Science Center, Peking University, Beijing 100191, China
- Electron Microscopy Analysis Laboratory, The Health Science Center, Peking University, Beijing 100191, China
- Center for Protein Science, Peking University, Beijing 100871, China
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yun Zhu
- Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Fei Sun
- Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, Guangdong, 510005, China
| |
Collapse
|
10
|
Xia Y, Zhang XH, Yamaguchi N, Morad M. Point mutations in RyR2 Ca2+-binding residues of human cardiomyocytes cause cellular remodelling of cardiac excitation contraction-coupling. Cardiovasc Res 2024; 120:44-55. [PMID: 37890099 PMCID: PMC10898933 DOI: 10.1093/cvr/cvad163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 07/17/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023] Open
Abstract
AIMS CRISPR/Cas9 gene edits of cardiac ryanodine receptor (RyR2) in human-induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) provide a novel platform for introducing mutations in RyR2 Ca2+-binding residues and examining the resulting excitation contraction (EC)-coupling remodelling consequences. METHODS AND RESULTS Ca2+-signalling phenotypes of mutations in RyR2 Ca2+-binding site residues associated with cardiac arrhythmia (RyR2-Q3925E) or not proven to cause cardiac pathology (RyR2-E3848A) were determined using ICa- and caffeine-triggered Ca2+ releases in voltage-clamped and total internal reflection fluorescence-imaged wild type and mutant cardiomyocytes infected with sarcoplasmic reticulum (SR)-targeted ER-GCaMP6 probe. (i) ICa- and caffeine-triggered Fura-2 or ER-GCaMP6 signals were suppressed, even when ICa was significantly enhanced in Q3925E and E3848A mutant cardiomyocytes; (ii) spontaneous beating (Fura-2 Ca2+ transients) persisted in mutant cells without the SR-release signals; (iii) while 5-20 mM caffeine failed to trigger Ca2+-release in voltage-clamped mutant cells, only ∼20% to ∼70% of intact myocytes responded respectively to caffeine; (iv) and 20 mM caffeine transients, however, activated slowly, were delayed, and variably suppressed by 2-APB, FCCP, or ruthenium red. CONCLUSION Mutating RyR2 Ca2+-binding residues, irrespective of their reported pathogenesis, suppressed both ICa- and caffeine-triggered Ca2+ releases, suggesting interaction between Ca2+- and caffeine-binding sites. Enhanced transmembrane calcium influx and remodelling of EC-coupling pathways may underlie the persistence of spontaneous beating in Ca2+-induced Ca2+ release-suppressed mutant myocytes.
Collapse
Affiliation(s)
- Yanli Xia
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
| | - Xiao-hua Zhang
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
| | - Naohiro Yamaguchi
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
| | - Martin Morad
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
| |
Collapse
|
11
|
Farrell RJ, Bredvik KG, Hoppa MB, Hennigan ST, Brown TA, Ryan TA. A ratiometric ER calcium sensor for quantitative comparisons across cell types and subcellular regions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.15.580492. [PMID: 38405980 PMCID: PMC10888930 DOI: 10.1101/2024.02.15.580492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
The endoplasmic reticulum (ER) is an important regulator of Ca 2 + in cells and dysregulation of ER calcium homeostasis can lead to numerous pathologies. Understanding how various pharmacological and genetic perturbations of ER Ca 2 + homeostasis impacts cellular physiology would likely be facilitated by more quantitative measurements of ER Ca 2 + levels that allow easier comparisons across conditions. Here, we developed a ratiometric version of our original ER-GCaMP probe that allows for more quantitative comparisons of the concentration of Ca 2 + in the ER across cell types and sub-cellular compartments. Using this approach we show that the resting concentration of ER Ca2+ in primary dissociated neurons is substantially lower than that in measured in embryonic fibroblasts.
Collapse
Affiliation(s)
- Ryan J Farrell
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA, 10065
- David Rockefeller Graduate Program, The Rockefeller University, New York, NY, USA, 10065
- Present Address: Neuroscience Institute, NYU Medical Center, New York, NY, USA, 10016
| | - Kirsten G Bredvik
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA, 10065
- Tri-Institutional M.D./Ph.D. Program, Weill Cornell Medicine, New York, NY, USA, 10065
| | - Michael B Hoppa
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA, 10065
- Present Address: Department of Biology, Dartmouth College, Hanover, NH 03755
| | - S Thomas Hennigan
- Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147
| | - Timothy A Brown
- Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147
| | - Timothy A Ryan
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA, 10065
- Lead Contact: correspondence
| |
Collapse
|
12
|
Wegener JW, Mitronova GY, ElShareif L, Quentin C, Belov V, Pochechueva T, Hasenfuss G, Ackermann L, Lehnart SE. A dual-targeted drug inhibits cardiac ryanodine receptor Ca 2+ leak but activates SERCA2a Ca 2+ uptake. Life Sci Alliance 2024; 7:e202302278. [PMID: 38012000 PMCID: PMC10681910 DOI: 10.26508/lsa.202302278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023] Open
Abstract
In the heart, genetic or acquired mishandling of diastolic [Ca2+] by ryanodine receptor type 2 (RyR2) overactivity correlates with risks of arrhythmia and sudden cardiac death. Strategies to avoid these risks include decrease of Ca2+ release by drugs modulating RyR2 activity or increase in Ca2+ uptake by drugs modulating SR Ca2+ ATPase (SERCA2a) activity. Here, we combine these strategies by developing experimental compounds that act simultaneously on both processes. Our screening efforts identified the new 1,4-benzothiazepine derivative GM1869 as a promising compound. Consequently, we comparatively studied the effects of the known RyR2 modulators Dantrolene and S36 together with GM1869 on RyR2 and SERCA2a activity in cardiomyocytes from wild type and arrhythmia-susceptible RyR2R2474S/+ mice by confocal live-cell imaging. All drugs reduced RyR2-mediated Ca2+ spark frequency but only GM1869 accelerated SERCA2a-mediated decay of Ca2+ transients in murine and human cardiomyocytes. Our data indicate that S36 and GM1869 are more suitable than dantrolene to directly modulate RyR2 activity, especially in RyR2R2474S/+ mice. Remarkably, GM1869 may represent a new dual-acting lead compound for maintenance of diastolic [Ca2+].
Collapse
Affiliation(s)
- Jörg W Wegener
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Gyuzel Y Mitronova
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Lina ElShareif
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
| | - Christine Quentin
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Vladimir Belov
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Tatiana Pochechueva
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Gerd Hasenfuss
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Lutz Ackermann
- Georg-August University of Göttingen, Institute of Organic and Biomolecular Chemistry, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Stephan E Lehnart
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| |
Collapse
|
13
|
Chirasani VR, Elferdink M, Kral M, Carter JS, Heitmann S, Meissner G, Yamaguchi N. Structural and functional interactions between the EF hand domain and S2-S3 loop in the type-1 ryanodine receptor ion channel. J Biol Chem 2024; 300:105606. [PMID: 38159862 PMCID: PMC10832476 DOI: 10.1016/j.jbc.2023.105606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 12/04/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024] Open
Abstract
Previous cryo-electron micrographs suggested that the skeletal muscle Ca2+ release channel, ryanodine receptor (RyR)1, is regulated by intricate interactions between the EF hand Ca2+ binding domain and the cytosolic loop (S2-S3 loop). However, the precise molecular details of these interactions and functional consequences of the interactions remain elusive. Here, we used molecular dynamics simulations to explore the specific amino acid pairs involved in hydrogen bond interactions within the EF hand-S2-S3 loop interface. Our simulations unveiled two key interactions: (1) K4101 (EF hand) with D4730 (S2-S3 loop) and (2) E4075, Q4078, and D4079 (EF hand) with R4736 (S2-S3 loop). To probe the functional significance of these interactions, we constructed mutant RyR1 complementary DNAs and expressed them in HEK293 cells for [3H]ryanodine binding assays. Our results demonstrated that mutations in the EF hand, specifically K4101E and K4101M, resulted in reduced affinities for Ca2+/Mg2+-dependent inhibitions. Interestingly, the K4101E mutation increased the affinity for Ca2+-dependent activation. Conversely, mutations in the S2-S3 loop, D4730K and D4730N, did not significantly change the affinities for Ca2+/Mg2+-dependent inhibitions. Our previous finding that skeletal disease-associated RyR1 mutations, R4736Q and R4736W, impaired Ca2+-dependent inhibition, is consistent with the current results. In silico mutagenesis analysis aligned with our functional data, indicating altered hydrogen bonding patterns upon mutations. Taken together, our findings emphasize the critical role of the EF hand-S2-S3 loop interaction in Ca2+/Mg2+-dependent inhibition of RyR1 and provide insights into potential therapeutic strategies targeting this domain interaction for the treatment of skeletal myopathies.
Collapse
Affiliation(s)
- Venkat R Chirasani
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; R.L. Juliano Structural Bioinformatics Core, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Millar Elferdink
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, USA; Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, South Carolina, USA; College of Charleston Honors College, Charleston, South Carolina, USA
| | - MacKenzie Kral
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, USA; Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, South Carolina, USA; College of Charleston Honors College, Charleston, South Carolina, USA
| | - Jordan S Carter
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, USA; Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, South Carolina, USA
| | - Savannah Heitmann
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, USA; Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, South Carolina, USA
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Naohiro Yamaguchi
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina, USA; Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, South Carolina, USA.
| |
Collapse
|
14
|
Joseph TT, Bu W, Haji-Ghassemi O, Chen YS, Woll K, Allen PD, Brannigan G, van Petegem F, Eckenhoff RG. Propofol directly binds and inhibits skeletal muscle ryanodine receptor 1 (RyR1). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.575040. [PMID: 38260485 PMCID: PMC10802444 DOI: 10.1101/2024.01.10.575040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
As the primary Ca 2+ release channel in skeletal muscle sarcoplasmic reticulum (SR), mutations in the type 1 ryanodine receptor (RyR1) or its binding partners underlie a constellation of muscle disorders, including malignant hyperthermia (MH). In patients with MH mutations, exposure to triggering drugs such as the halogenated volatile anesthetics biases RyR1 to an open state, resulting in uncontrolled Ca 2+ release, sarcomere tension and heat production. Restoration of Ca 2+ into the SR also consumes ATP, generating a further untenable metabolic load. When anesthetizing patients with known MH mutations, the non-triggering intravenous general anesthetic propofol is commonly substituted for triggering anesthetics. Evidence of direct binding of anesthetic agents to RyR1 or its binding partners is scant, and the atomic-level interactions of propofol with RyR1 are entirely unknown. Here, we show that propofol decreases RyR1 opening in heavy SR vesicles and planar lipid bilayers, and that it inhibits activator-induced Ca 2+ release from SR in human skeletal muscle. In addition to confirming direct binding, photoaffinity labeling using m- azipropofol (AziP m ) revealed several putative propofol binding sites on RyR1. Prediction of binding affinity by molecular dynamics simulation suggests that propofol binds at least one of these sites at clinical concentrations. These findings invite the hypothesis that in addition to propofol not triggering MH, it may also be protective against MH by inhibiting induced Ca 2+ flux through RyR1.
Collapse
|
15
|
Akizawa H, Lopes EM, Fissore RA. Zn 2+ is essential for Ca 2+ oscillations in mouse eggs. eLife 2023; 12:RP88082. [PMID: 38099643 PMCID: PMC10723796 DOI: 10.7554/elife.88082] [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: 12/17/2023] Open
Abstract
Changes in the intracellular concentration of free calcium (Ca2+) underpin egg activation and initiation of development in animals and plants. In mammals, the Ca2+ release is periodical, known as Ca2+ oscillations, and mediated by the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1). Another divalent cation, zinc (Zn2+), increases exponentially during oocyte maturation and is vital for meiotic transitions, arrests, and polyspermy prevention. It is unknown if these pivotal cations interplay during fertilization. Here, using mouse eggs, we showed that basal concentrations of labile Zn2+ are indispensable for sperm-initiated Ca2+ oscillations because Zn2+-deficient conditions induced by cell-permeable chelators abrogated Ca2+ responses evoked by fertilization and other physiological and pharmacological agonists. We also found that chemically or genetically generated eggs with lower levels of labile Zn2+ displayed reduced IP3R1 sensitivity and diminished ER Ca2+ leak despite the stable content of the stores and IP3R1 mass. Resupplying Zn2+ restarted Ca2+ oscillations, but excessive Zn2+ prevented and terminated them, hindering IP3R1 responsiveness. The findings suggest that a window of Zn2+ concentrations is required for Ca2+ responses and IP3R1 function in eggs, ensuring optimal response to fertilization and egg activation.
Collapse
Affiliation(s)
- Hiroki Akizawa
- Department of Veterinary and Animal Sciences, University of Massachusetts AmherstAmherstUnited States
| | - Emily M Lopes
- Department of Veterinary and Animal Sciences, University of Massachusetts AmherstAmherstUnited States
- Molecular and Cellular Biology Graduate Program, University of MassachusettsAmherstUnited States
| | - Rafael A Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts AmherstAmherstUnited States
| |
Collapse
|
16
|
Mitronova GY, Quentin C, Belov VN, Wegener JW, Kiszka KA, Lehnart SE. 1,4-Benzothiazepines with Cyclopropanol Groups and Their Structural Analogues Exhibit Both RyR2-Stabilizing and SERCA2a-Stimulating Activities. J Med Chem 2023; 66:15761-15775. [PMID: 37991191 PMCID: PMC10726367 DOI: 10.1021/acs.jmedchem.3c01235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/24/2023] [Accepted: 11/07/2023] [Indexed: 11/23/2023]
Abstract
To discover new multifunctional agents for the treatment of cardiovascular diseases, we designed and synthesized a series of compounds with a cyclopropyl alcohol moiety and evaluated them in biochemical assays. Biological screening identified derivatives with dual activity: preventing Ca2+ leak through ryanodine receptor 2 (RyR2) and enhancing cardiac sarco-endoplasmic reticulum (SR) Ca2+ load by activation of Ca2+-dependent ATPase 2a (SERCA2a). The compounds that stabilize RyR2 at micro- and nanomolar concentrations are either structurally related to RyR-stabilizing drugs or Rycals or have structures similar to them. The novel compounds also demonstrate a good ability to increase ATP hydrolysis mediated by SERCA2a activity in cardiac microsomes, e.g., the half-maximal effective concentration (EC50) was as low as 383 nM for compound 12a, which is 1,4-benzothiazepine with two cyclopropanol groups. Our findings indicate that these derivatives can be considered as new lead compounds to improve cardiac function in heart failure.
Collapse
Affiliation(s)
- Gyuzel Y. Mitronova
- Department
of NanoBiophotonics, Max Planck Institute
for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
- German
Centre for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen 37075, Germany
| | - Christine Quentin
- Department
of NanoBiophotonics, Max Planck Institute
for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Vladimir N. Belov
- Department
of NanoBiophotonics, Max Planck Institute
for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Jörg W. Wegener
- Department
of Cardiology & Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Strasse 42a, Göttingen 37075, Germany
- German
Centre for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen 37075, Germany
| | - Kamila A. Kiszka
- Department
of NanoBiophotonics, Max Planck Institute
for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Stephan E. Lehnart
- Department
of Cardiology & Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Robert-Koch-Strasse 42a, Göttingen 37075, Germany
- German
Centre for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen 37075, Germany
| |
Collapse
|
17
|
Noda Y, Miyoshi H, Benucci S, Gonzalez A, Bandschapp O, Girard T, Treves S, Zorzato F. Functional characterization of RYR1 variants identified in malignant hyperthermia susceptible individuals. Neuromuscul Disord 2023; 33:951-963. [PMID: 37996280 DOI: 10.1016/j.nmd.2023.10.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/25/2023]
Abstract
Malignant hyperthermia is a pharmacogenetic disorder triggered by halogenated anesthetic agents in genetically predisposed individuals. Approximately 70 % of these individuals carry mutations in RYR1, the gene encoding the ryanodine receptor calcium channel of skeletal muscle. In this study, we performed functional analysis of 5 RYR1 variants identified in members from 8 families who had been diagnosed by the IVCT. Of the 68 individuals enrolled in the study, 43 were diagnosed as MHS, 23 as MHN, and 2 individuals were not tested. Here we demonstrate that the 5 RyR1 variants cause hypersensitivity to RyR1 agonist-mediated calcium release. According to the EMHG scoring matrix these five genetic variants can be classified as follows: c.8638G>A (p.E2880K) and c.11314C>T (p.R3772W) likely pathogenic, c.11416G>A (p.G3806R), c.14627A>G (p.K4876R) and c.14813T>C (p.I4938T), pathogenic (RefSeq NM_000540.3). We propose that the newly functionally characterized RYR1 variants, be included in the panel of variants to be used for the molecular diagnosis of MHS.
Collapse
Affiliation(s)
- Yuko Noda
- Departments of Biomedicine and Neurology, Basel University Hospital, Hebelstrasse 20, Basel 4031, Switzerland; Department of Anesthesiology, Hiroshima University Hospital, 1-2-3 Kasumi Minami-ku Hiroshima, 734-8551, Japan
| | - Hirotsugu Miyoshi
- Department of Anesthesiology, Hiroshima University Hospital, 1-2-3 Kasumi Minami-ku Hiroshima, 734-8551, Japan
| | - Sofia Benucci
- Departments of Biomedicine and Neurology, Basel University Hospital, Hebelstrasse 20, Basel 4031, Switzerland
| | | | | | - Thierry Girard
- Anesthesiology, Spitalstrasse 21, Basel 4031, Switzerland
| | - Susan Treves
- Departments of Biomedicine and Neurology, Basel University Hospital, Hebelstrasse 20, Basel 4031, Switzerland; Department of Life Science and Biotechnology, University of Ferrara, Via Borsari 46, Ferrara 44100, Italy.
| | - Francesco Zorzato
- Departments of Biomedicine and Neurology, Basel University Hospital, Hebelstrasse 20, Basel 4031, Switzerland; Department of Life Science and Biotechnology, University of Ferrara, Via Borsari 46, Ferrara 44100, Italy.
| |
Collapse
|
18
|
Song X, Kirtipal N, Lee S, Malý P, Bharadwaj S. Current therapeutic targets and multifaceted physiological impacts of caffeine. Phytother Res 2023; 37:5558-5598. [PMID: 37679309 DOI: 10.1002/ptr.8000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 08/04/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023]
Abstract
Caffeine, which shares consubstantial structural similarity with purine adenosine, has been demonstrated as a nonselective adenosine receptor antagonist for eliciting most of the biological functions at physiologically relevant dosages. Accumulating evidence supports caffeine's beneficial effects against different disorders, such as total cardiovascular diseases and type 2 diabetes. Conversely, paradoxical effects are also linked to caffeine ingestion in humans including hypertension-hypotension and tachycardia-bradycardia. These observations suggest the association of caffeine action with its ingested concentration and/or concurrent interaction with preferential molecular targets to direct explicit events in the human body. Thus, a coherent analysis of the functional targets of caffeine, relevant to normal physiology, and disease pathophysiology, is required to understand the pharmacology of caffeine. This review provides a broad overview of the experimentally validated targets of caffeine, particularly those of therapeutic interest, and the impacts of caffeine on organ-specific physiology and pathophysiology. Overall, the available empirical and epidemiological evidence supports the dose-dependent functional activities of caffeine and advocates for further studies to get insights into the caffeine-induced changes under specific conditions, such as asthma, DNA repair, and cancer, in view of its therapeutic applications.
Collapse
Affiliation(s)
- Xinjie Song
- Zhejiang Provincial Key Lab for Chemical and Biological Processing Technology of Farm Product, School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou, China
| | - Nikhil Kirtipal
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Sunjae Lee
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Petr Malý
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences v.v.i, BIOCEV Research Center, Vestec, Czech Republic
| | - Shiv Bharadwaj
- Laboratory of Ligand Engineering, Institute of Biotechnology of the Czech Academy of Sciences v.v.i, BIOCEV Research Center, Vestec, Czech Republic
| |
Collapse
|
19
|
Akizawa H, Lopes E, Fissore RA. Zn 2+ is Essential for Ca 2+ Oscillations in Mouse Eggs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.13.536745. [PMID: 37131581 PMCID: PMC10153198 DOI: 10.1101/2023.04.13.536745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Changes in the intracellular concentration of free calcium (Ca2+) underpin egg activation and initiation of development in animals and plants. In mammals, the Ca2+ release is periodical, known as Ca2+ oscillations, and mediated by the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1). Another divalent cation, zinc (Zn2+), increases exponentially during oocyte maturation and is vital for meiotic transitions, arrests, and polyspermy prevention. It is unknown if these pivotal cations interplay during fertilization. Here, using mouse eggs, we showed that basal concentrations of labile Zn2+ are indispensable for sperm-initiated Ca2+ oscillations because Zn2+-deficient conditions induced by cell-permeable chelators abrogated Ca2+ responses evoked by fertilization and other physiological and pharmacological agonists. We also found that chemically- or genetically generated eggs with lower levels of labile Zn2+ displayed reduced IP3R1 sensitivity and diminished ER Ca2+ leak despite the stable content of the stores and IP3R1 mass. Resupplying Zn2+ restarted Ca2+ oscillations, but excessive Zn2+ prevented and terminated them, hindering IP3R1 responsiveness. The findings suggest that a window of Zn2+ concentrations is required for Ca2+ responses and IP3R1 function in eggs, ensuring optimal response to fertilization and egg activation.
Collapse
Affiliation(s)
- Hiroki Akizawa
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, Massachusetts, 01003, United States
| | - Emily Lopes
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, Massachusetts, 01003, United States
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, 01003, United States
| | - Rafael A. Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, Massachusetts, 01003, United States
| |
Collapse
|
20
|
Gong Y, Ge L, Li Q, Gong J, Chen M, Gao H, Kang J, Yu T, Li J, Xu H. Ethanol Causes Cell Death and Neuronal Differentiation Defect During Initial Neurogenesis of the Neural Retina by Disrupting Calcium Signaling in Human Retinal Organoids. Stem Cell Rev Rep 2023; 19:2790-2806. [PMID: 37603136 DOI: 10.1007/s12015-023-10604-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2023] [Indexed: 08/22/2023]
Abstract
Fetal Alcohol Syndrome (FAS) affects a significant proportion, exceeding 90%, of afflicted children, leading to severe ocular aberrations such as microphthalmia and optic nerve hypoplasia. During the early stages of pregnancy, the commencement of neural retina neurogenesis represents a critical period for human eye development, concurrently exposing the developing retinal structures to the highest risk of prenatal ethanol exposure due to a lack of awareness. Despite the paramount importance of this period, the precise influence and underlying mechanisms of short-term ethanol exposure on the developmental process of the human neural retina have remained largely elusive. In this study, we utilize the human embryonic stem cells derived retinal organoids (hROs) to recapitulate the initial retinal neurogenesis and find that 1% (v/v) ethanol slows the growth of hROs by inducing robust cell death and retinal ganglion cell differentiation defect. Bulk RNA-seq analysis and two-photon microscope live calcium imaging reveal altered calcium signaling dynamics derived from ethanol-induced down-regulation of RYR1 and CACNA1S. Moreover, the calcium-binding protein RET, one of the downstream effector genes of the calcium signaling pathway, synergistically integrates ethanol and calcium signals to abort neuron differentiation and cause cell death. To sum up, our study illustrates the effect and molecular mechanism of ethanol on the initial neurogenesis of the human embryonic neural retina, providing a novel interpretation of the ocular phenotype of FAS and potentially informing preventative measures for susceptible populations.
Collapse
Affiliation(s)
- Yu Gong
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
- Department of Ophthalmology, University-Town Hospital of Chongqing Medical University, Chongqing, China
| | - Lingling Ge
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Qiyou Li
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Jing Gong
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400044, China
| | - Min Chen
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Hui Gao
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Jiahui Kang
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China
| | - Ting Yu
- Department of Clinical Laboratory, The 89th Hospital of The People's Liberation Army, Weifang, People's Republic of China
| | - Jiawen Li
- Department of Ophthalmology, University-Town Hospital of Chongqing Medical University, Chongqing, China.
| | - Haiwei Xu
- Southwest Hospital/ Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, People's Republic of China.
- Key Lab of Visual Damage and Regeneration & Restoration of Chongqing, Chongqing, People's Republic of China.
| |
Collapse
|
21
|
Paknejad N, Sapuru V, Hite RK. Structural titration reveals Ca 2+-dependent conformational landscape of the IP 3 receptor. Nat Commun 2023; 14:6897. [PMID: 37898605 PMCID: PMC10613215 DOI: 10.1038/s41467-023-42707-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 10/18/2023] [Indexed: 10/30/2023] Open
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are endoplasmic reticulum Ca2+ channels whose biphasic dependence on cytosolic Ca2+ gives rise to Ca2+ oscillations that regulate fertilization, cell division and cell death. Despite the critical roles of IP3R-mediated Ca2+ responses, the structural underpinnings of the biphasic Ca2+ dependence that underlies Ca2+ oscillations are incompletely understood. Here, we collect cryo-EM images of an IP3R with Ca2+ concentrations spanning five orders of magnitude. Unbiased image analysis reveals that Ca2+ binding does not explicitly induce conformational changes but rather biases a complex conformational landscape consisting of resting, preactivated, activated, and inhibited states. Using particle counts as a proxy for relative conformational free energy, we demonstrate that Ca2+ binding at a high-affinity site allows IP3Rs to activate by escaping a low-energy resting state through an ensemble of preactivated states. At high Ca2+ concentrations, IP3Rs preferentially enter an inhibited state stabilized by a second, low-affinity Ca2+ binding site. Together, these studies provide a mechanistic basis for the biphasic Ca2+-dependence of IP3R channel activity.
Collapse
Affiliation(s)
- Navid Paknejad
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Physiology, Biophysics, and Systems Biology (PBSB) Program, Weill Cornell Graduate School of Biomedical Sciences, 1300 York Avenue, New York, NY, 10065, USA
| | - Vinay Sapuru
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Physiology, Biophysics, and Systems Biology (PBSB) Program, Weill Cornell Graduate School of Biomedical Sciences, 1300 York Avenue, New York, NY, 10065, USA
| | - Richard K Hite
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.
| |
Collapse
|
22
|
Šeflová J, Schwarz JA, Smith AN, Svensson B, Blackwell DJ, Phillips TA, Nikolaienko R, Bovo E, Rebbeck RT, Zima AV, Thomas DD, Van Petegem F, Knollmann BC, Johnston JN, Robia SL, Cornea RL. RyR2 Binding of an Antiarrhythmic Cyclic Depsipeptide Mapped Using Confocal Fluorescence Lifetime Detection of FRET. ACS Chem Biol 2023; 18:2290-2299. [PMID: 37769131 DOI: 10.1021/acschembio.3c00376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Hyperactivity of cardiac sarcoplasmic reticulum (SR) ryanodine receptor (RyR2) Ca2+-release channels contributes to heart failure and arrhythmias. Reducing the RyR2 activity, particularly during cardiac relaxation (diastole), is a desirable therapeutic goal. We previously reported that the unnatural enantiomer (ent) of an insect-RyR activator, verticilide, inhibits porcine and mouse RyR2 at diastolic (nanomolar) Ca2+ and has in vivo efficacy against atrial and ventricular arrhythmia. To determine the ent-verticilide structural mode of action on RyR2 and guide its further development via medicinal chemistry structure-activity relationship studies, here, we used fluorescence lifetime (FLT)-measurements of Förster resonance energy transfer (FRET) in HEK293 cells expressing human RyR2. For these studies, we used an RyR-specific FRET molecular-toolkit and computational methods for trilateration (i.e., using distances to locate a point of interest). Multiexponential analysis of FLT-FRET measurements between four donor-labeled FKBP12.6 variants and acceptor-labeled ent-verticilide yielded distance relationships placing the acceptor probe at two candidate loci within the RyR2 cryo-EM map. One locus is within the Ry12 domain (at the corner periphery of the RyR2 tetrameric complex). The other locus is sandwiched at the interface between helical domain 1 and the SPRY3 domain. These findings document RyR2-target engagement by ent-verticilide, reveal new insight into the mechanism of action of this new class of RyR2-targeting drug candidate, and can serve as input in future computational determinations of the ent-verticilide binding site on RyR2 that will inform structure-activity studies for lead optimization.
Collapse
Affiliation(s)
- Jaroslava Šeflová
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Jacob A Schwarz
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Abigail N Smith
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Bengt Svensson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Daniel J Blackwell
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Taylor A Phillips
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Roman Nikolaienko
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Elisa Bovo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Robyn T Rebbeck
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - David D Thomas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Björn C Knollmann
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jeffrey N Johnston
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
| | - Răzvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
23
|
Raisch T, Raunser S. The modes of action of ion-channel-targeting neurotoxic insecticides: lessons from structural biology. Nat Struct Mol Biol 2023; 30:1411-1427. [PMID: 37845413 DOI: 10.1038/s41594-023-01113-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 08/31/2023] [Indexed: 10/18/2023]
Abstract
Insecticides are indispensable tools for plant protection in modern agriculture. Despite having highly heterogeneous structures, many neurotoxic insecticides use similar principles to inhibit or deregulate neuronal ion channels. Insecticides targeting pentameric ligand-gated channels are structural mimetics of neurotransmitters or manipulate and deregulate the proteins. Those binding to (pseudo-)tetrameric voltage-gated(-like) channels, on the other hand, are natural or synthetic compounds that directly block the ion-conducting pore or prevent conformational changes in the transmembrane domain necessary for opening and closing the pore. The use of a limited number of inhibition mechanisms can be problematic when resistances arise and become more widespread. Therefore, there is a rising interest in the development of insecticides with novel mechanisms that evade resistance and are pest-insect-specific. During the last decade, most known insecticide targets, many with bound compounds, have been structurally characterized, bringing the rational design of novel classes of agrochemicals within closer reach than ever before.
Collapse
Affiliation(s)
- Tobias Raisch
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
| |
Collapse
|
24
|
Dridi H, Santulli G, Bahlouli L, Miotto MC, Weninger G, Marks AR. Mitochondrial Calcium Overload Plays a Causal Role in Oxidative Stress in the Failing Heart. Biomolecules 2023; 13:1409. [PMID: 37759809 PMCID: PMC10527470 DOI: 10.3390/biom13091409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/13/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023] Open
Abstract
Heart failure is a serious global health challenge, affecting more than 6.2 million people in the United States and is projected to reach over 8 million by 2030. Independent of etiology, failing hearts share common features, including defective calcium (Ca2+) handling, mitochondrial Ca2+ overload, and oxidative stress. In cardiomyocytes, Ca2+ not only regulates excitation-contraction coupling, but also mitochondrial metabolism and oxidative stress signaling, thereby controlling the function and actual destiny of the cell. Understanding the mechanisms of mitochondrial Ca2+ uptake and the molecular pathways involved in the regulation of increased mitochondrial Ca2+ influx is an ongoing challenge in order to identify novel therapeutic targets to alleviate the burden of heart failure. In this review, we discuss the mechanisms underlying altered mitochondrial Ca2+ handling in heart failure and the potential therapeutic strategies.
Collapse
Affiliation(s)
- Haikel Dridi
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| | - Gaetano Santulli
- Department of Medicine, Division of Cardiology, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, New York, NY 10461, USA;
| | - Laith Bahlouli
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| | - Marco C. Miotto
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| | - Gunnar Weninger
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| | - Andrew R. Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| |
Collapse
|
25
|
Lee CS, Jung SY, Yee RSZ, Agha NH, Hong J, Chang T, Babcock LW, Fleischman JD, Clayton B, Hanna AD, Ward CS, Lanza D, Hurley AE, Zhang P, Wehrens XHT, Lagor WR, Rodney GG, Hamilton SL. Speg interactions that regulate the stability of excitation-contraction coupling protein complexes in triads and dyads. Commun Biol 2023; 6:942. [PMID: 37709832 PMCID: PMC10502019 DOI: 10.1038/s42003-023-05330-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 09/07/2023] [Indexed: 09/16/2023] Open
Abstract
Here we show that striated muscle preferentially expressed protein kinase α (Spegα) maintains cardiac function in hearts with Spegβ deficiency. Speg is required for stability of excitation-contraction coupling (ECC) complexes and interacts with esterase D (Esd), Cardiomyopathy-Associated Protein 5 (Cmya5), and Fibronectin Type III and SPRY Domain Containing 2 (Fsd2) in cardiac and skeletal muscle. Mice with a sequence encoding a V5/HA tag inserted into the first exon of the Speg gene (HA-Speg mice) display a >90% decrease in Spegβ but Spegα is expressed at ~50% of normal levels. Mice deficient in both Spegα and Speg β (Speg KO mice) develop a severe dilated cardiomyopathy and muscle weakness and atrophy, but HA-Speg mice display mild muscle weakness with no cardiac involvement. Spegα in HA-Speg mice suppresses Ca2+ leak, proteolytic cleavage of Jph2, and disruption of transverse tubules. Despite it's low levels, HA-Spegβ immunoprecipitation identified Esd, Cmya5 and Fsd2 as Spegβ binding partners that localize to triads and dyads to stabilize ECC complexes. This study suggests that Spegα and Spegβ display functional redundancy, identifies Esd, Cmya5 and Fsd2 as components of both cardiac dyads and skeletal muscle triads and lays the groundwork for the identification of new therapeutic targets for centronuclear myopathy.
Collapse
Affiliation(s)
- Chang Seok Lee
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Sung Yun Jung
- Department of Biochemistry, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Rachel Sue Zhen Yee
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Nadia H Agha
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Jin Hong
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Ting Chang
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Lyle W Babcock
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Jorie D Fleischman
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Benjamin Clayton
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Amy D Hanna
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Christopher S Ward
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Denise Lanza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Ayrea E Hurley
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Pumin Zhang
- The First Affiliated Hospital, Zhejiang University Medical School, Hangzhou, China
| | - Xander H T Wehrens
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - William R Lagor
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - George G Rodney
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Susan L Hamilton
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA.
| |
Collapse
|
26
|
Magyar ZÉ, Hevesi J, Groom L, Dirksen RT, Almássy J. Function of a mutant ryanodine receptor (T4709M) linked to congenital myopathy. Sci Rep 2023; 13:14659. [PMID: 37670077 PMCID: PMC10480487 DOI: 10.1038/s41598-023-41801-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 08/31/2023] [Indexed: 09/07/2023] Open
Abstract
Physiological muscle contraction requires an intact ligand gating mechanism of the ryanodine receptor 1 (RyR1), the Ca2+-release channel of the sarcoplasmic reticulum. Some mutations impair the gating and thus cause muscle disease. The RyR1 mutation T4706M is linked to a myopathy characterized by muscle weakness. Although, low expression of the T4706M RyR1 protein can explain in part the symptoms, little is known about the function RyR1 channels with this mutation. In order to learn whether this mutation alters channel function in a manner that can account for the observed symptoms, we examined RyR1 channels isolated from mice homozygous for the T4709M (TM) mutation at the single channel level. Ligands, including Ca2+, ATP, Mg2+ and the RyR inhibitor dantrolene were tested. The full conductance of the TM channel was the same as that of wild type (wt) channels and a population of partial open (subconductive) states were not observed. However, two unique sub-populations of TM RyRs were identified. One half of the TM channels exhibited high open probability at low (100 nM) and high (50 μM) cytoplasmic [Ca2+], resulting in Ca2+-insensitive, constitutively high Po channels. The rest of the TM channels exhibited significantly lower activity within the physiologically relevant range of cytoplasmic [Ca2+], compared to wt. TM channels retained normal Mg2+ block, modulation by ATP, and inhibition by dantrolene. Together, these results suggest that the TM mutation results in a combination of primary and secondary RyR1 dysfunctions that contribute to disease pathogenesis.
Collapse
Affiliation(s)
- Zsuzsanna É Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Judit Hevesi
- Department of Orthodontics, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
- Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Linda Groom
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - János Almássy
- Department of Physiology, Semmelweis University, Budapest, Hungary.
| |
Collapse
|
27
|
Magyar ZÉ, Bauer J, Bauerová-Hlinková V, Jóna I, Gaburjakova J, Gaburjakova M, Almássy J. Eu 3+ detects two functionally distinct luminal Ca 2+ binding sites in ryanodine receptors. Biophys J 2023; 122:3516-3531. [PMID: 37533257 PMCID: PMC10502479 DOI: 10.1016/j.bpj.2023.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/26/2023] [Accepted: 07/31/2023] [Indexed: 08/04/2023] Open
Abstract
Ryanodine receptors (RyRs) are Ca2+ release channels, gated by Ca2+ in the cytosol and the sarcoplasmic reticulum lumen. Their regulation is impaired in certain cardiac and muscle diseases. Although a lot of data is available on the luminal Ca2+ regulation of RyR, its interpretation is complicated by the possibility that the divalent ions used to probe the luminal binding sites may contaminate the cytoplasmic sites by crossing the channel pore. In this study, we used Eu3+, an impermeable agonist of Ca2+ binding sites, as a probe to avoid this complication and to gain more specific information about the function of the luminal Ca2+ sensor. Single-channel currents were measured from skeletal muscle and cardiac RyRs (RyR1 and RyR2) using the lipid bilayer technique. We show that RyR2 is activated by the luminal addition of Ca2+, whereas RyR1 is inhibited. These results were qualitatively reproducible using Eu3+. The luminal regulation of RyR1 carrying a mutation associated with malignant hyperthermia was not different from that of the wild-type. RyR1 inhibition by Eu3+ was extremely voltage dependent, whereas RyR2 activation did not depend on the membrane potential. These results suggest that the RyR1 inhibition site is in the membrane's electric field (channel pore), whereas the RyR2 activation site is outside. Using in silico analysis and previous results, we predicted putative Ca2+ binding site sequences. We propose that RyR2 bears an activation site, which is missing in RyR1, but both isoforms share the same inhibitory Ca2+ binding site near the channel gate.
Collapse
Affiliation(s)
- Zsuzsanna É Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Jacob Bauer
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | | | - István Jóna
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Jana Gaburjakova
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Marta Gaburjakova
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - János Almássy
- Department of Physiology, Semmelweis University, Budapest, Hungary.
| |
Collapse
|
28
|
Cholak S, Saville JW, Zhu X, Berezuk AM, Tuttle KS, Haji-Ghassemi O, Alvarado FJ, Van Petegem F, Subramaniam S. Allosteric modulation of ryanodine receptor RyR1 by nucleotide derivatives. Structure 2023; 31:790-800.e4. [PMID: 37192614 PMCID: PMC10569317 DOI: 10.1016/j.str.2023.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 02/22/2023] [Accepted: 04/19/2023] [Indexed: 05/18/2023]
Abstract
The coordinated release of Ca2+ from the sarcoplasmic reticulum (SR) is critical for excitation-contraction coupling. This release is facilitated by ryanodine receptors (RyRs) that are embedded in the SR membrane. In skeletal muscle, activity of RyR1 is regulated by metabolites such as ATP, which upon binding increase channel open probability (Po). To obtain structural insights into the mechanism of RyR1 priming by ATP, we determined several cryo-EM structures of RyR1 bound individually to ATP-γ-S, ADP, AMP, adenosine, adenine, and cAMP. We demonstrate that adenine and adenosine bind RyR1, but AMP is the smallest ATP derivative capable of inducing long-range (>170 Å) structural rearrangements associated with channel activation, establishing a structural basis for key binding site interactions that are the threshold for triggering quaternary structural changes. Our finding that cAMP also induces these structural changes and results in increased channel opening suggests its potential role as an endogenous modulator of RyR1 conductance.
Collapse
Affiliation(s)
- Spencer Cholak
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - James W Saville
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Xing Zhu
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Alison M Berezuk
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Katharine S Tuttle
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Omid Haji-Ghassemi
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Francisco J Alvarado
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
| |
Collapse
|
29
|
Smith HA, Thillaiappan NB, Rossi AM. IP 3 receptors: An "elementary" journey from structure to signals. Cell Calcium 2023; 113:102761. [PMID: 37271052 DOI: 10.1016/j.ceca.2023.102761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 06/06/2023]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are large tetrameric channels which sit mostly in the membrane of the endoplasmic reticulum (ER) and mediate Ca2+ release from intracellular stores in response to extracellular stimuli in almost all cells. Dual regulation of IP3Rs by IP3 and Ca2+ itself, upstream "licensing", and the arrangement of IP3Rs into small clusters in the ER membrane, allow IP3Rs to generate spatially and temporally diverse Ca2+ signals. The characteristic biphasic regulation of IP3Rs by cytosolic Ca2+ concentration underpins regenerative Ca2+ signals by Ca2+-induced Ca2+-release, while also preventing uncontrolled explosive Ca2+ release. In this way, cells can harness a simple ion such as Ca2+ as a near-universal intracellular messenger to regulate diverse cellular functions, including those with conflicting outcomes such as cell survival and cell death. High-resolution structures of the IP3R bound to IP3 and Ca2+ in different combinations have together started to unravel the workings of this giant channel. Here we discuss, in the context of recently published structures, how the tight regulation of IP3Rs and their cellular geography lead to generation of "elementary" local Ca2+ signals known as Ca2+ "puffs", which form the fundamental bottleneck through which all IP3-mediated cytosolic Ca2+ signals must first pass.
Collapse
Affiliation(s)
- Holly A Smith
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | | | - Ana M Rossi
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom.
| |
Collapse
|
30
|
Wu M, Wu C, Song T, Pan K, Wang Y, Liu Z. Structure and transport mechanism of the human calcium pump SPCA1. Cell Res 2023; 33:533-545. [PMID: 37258749 PMCID: PMC10313705 DOI: 10.1038/s41422-023-00827-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/08/2023] [Indexed: 06/02/2023] Open
Abstract
Secretory-pathway Ca2+-ATPases (SPCAs) play critical roles in maintaining Ca2+ homeostasis, but the exact mechanism of SPCAs-mediated Ca2+ transport remains unclear. Here, we determined six cryo-electron microscopy (cryo-EM) structures of human SPCA1 (hSPCA1) in a series of intermediate states, revealing a near-complete conformational cycle. With the aid of molecular dynamics simulations, these structures offer a clear structural basis for Ca2+ entry and release in hSPCA1. We found that hSPCA1 undergoes unique conformational changes during ATP binding and phosphorylation compared to other well-studied P-type II ATPases. In addition, we observed a conformational distortion of the Ca2+-binding site induced by the separation of transmembrane helices 4L and 6, unveiling a distinct Ca2+ release mechanism. Particularly, we determined a structure of the long-sought CaE2P state of P-type IIA ATPases, providing valuable insights into the Ca2+ transport cycle. Together, these findings enhance our understanding of Ca2+ transport by hSPCA1 and broaden our knowledge of P-type ATPases.
Collapse
Affiliation(s)
- Mengqi Wu
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Cang Wu
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Tiefeng Song
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kewu Pan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yong Wang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining, Zhejiang, China.
| | - Zhongmin Liu
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| |
Collapse
|
31
|
Thomas NL, Dart C, Helassa N. Editorial: The role of calcium and calcium binding proteins in cell physiology and disease. Front Physiol 2023; 14:1228885. [PMID: 37362430 PMCID: PMC10289193 DOI: 10.3389/fphys.2023.1228885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 06/02/2023] [Indexed: 06/28/2023] Open
Affiliation(s)
- N. Lowri Thomas
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - C. Dart
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, North West England, United Kingdom
| | - N. Helassa
- Department of Cardiovascular and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, North West England, United Kingdom
| |
Collapse
|
32
|
Du J, Fu Y. Diamide insecticides targeting insect ryanodine receptors: Mechanism and application prospect. Biochem Biophys Res Commun 2023; 670:19-26. [PMID: 37271036 DOI: 10.1016/j.bbrc.2023.05.107] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 05/25/2023] [Indexed: 06/06/2023]
Abstract
As a Lepidoptera pest, Spodoptera frugiperda has become one of the major migratory pests causing significant damage to crops. It should prevent and control Spodoptera frugiperda with strong reproductive ability, adaptability, and migration ability, and reduce economic losses as much as possible. Chemical insecticides are mainly used in the emergency control of Spodoptera frugiperda. Diamide insecticide is a kind of pesticide that specifically targets the ryanodine receptor of Lepidopteran pests, which makes it safe, effective, targeted, and low toxicity to mammals. So, it is one of the most concerned and fastest-growing pesticide products after neonicotinoid pesticides. Intracellular Ca2+ concentration can be regulated by ryanodine receptors, and the continuous release of Ca2+ eventually leads to the death of pests and achieve the insecticidal effect. This review introduces in detail diamide insecticides that mainly play roles in stomach toxicity, as well as its specific target-ryanodine receptor, and analyzes how the diamide insecticide acts on the ryanodine receptor and how its mechanism of action can provide a theoretical basis for the rational use of highly effective insecticides and solve the resistance problem. Moreover, we also propose several recommendations for reducing resistance to diamide insecticides, and provide a reference for chemical control and resistance studies of Spodoptera frugiperda, which has broad development prospects in today's increasingly concerned about the ecological environment and advocating green environmental protection.
Collapse
Affiliation(s)
- Juan Du
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Yuejun Fu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China.
| |
Collapse
|
33
|
Haji-Ghassemi O, Chen YS, Woll K, Gurrola GB, Valdivia CR, Cai W, Li S, Valdivia HH, Van Petegem F. Cryo-EM analysis of scorpion toxin binding to Ryanodine Receptors reveals subconductance that is abolished by PKA phosphorylation. SCIENCE ADVANCES 2023; 9:eadf4936. [PMID: 37224245 PMCID: PMC10208580 DOI: 10.1126/sciadv.adf4936] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 04/18/2023] [Indexed: 05/26/2023]
Abstract
Calcins are peptides from scorpion venom with the unique ability to cross cell membranes, gaining access to intracellular targets. Ryanodine Receptors (RyR) are intracellular ion channels that control release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. Calcins target RyRs and induce long-lived subconductance states, whereby single-channel currents are decreased. We used cryo-electron microscopy to reveal the binding and structural effects of imperacalcin, showing that it opens the channel pore and causes large asymmetry throughout the cytosolic assembly of the tetrameric RyR. This also creates multiple extended ion conduction pathways beyond the transmembrane region, resulting in subconductance. Phosphorylation of imperacalcin by protein kinase A prevents its binding to RyR through direct steric hindrance, showing how posttranslational modifications made by the host organism can determine the fate of a natural toxin. The structure provides a direct template for developing calcin analogs that result in full channel block, with potential to treat RyR-related disorders.
Collapse
Affiliation(s)
- Omid Haji-Ghassemi
- Department of Biochemistry and Molecular Biology, Life Sciences Centre, University of British Columbia, Vancouver, BC, Canada
| | - Yu Seby Chen
- Department of Biochemistry and Molecular Biology, Life Sciences Centre, University of British Columbia, Vancouver, BC, Canada
| | - Kellie Woll
- Department of Biochemistry and Molecular Biology, Life Sciences Centre, University of British Columbia, Vancouver, BC, Canada
| | - Georgina B. Gurrola
- Universidad Nacional Autónoma de México, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotechnología, Cuaernavaca, Morelos 62271, Mexico
| | - Carmen R. Valdivia
- Department of Medicine and Cardiovascular Research Center, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Wenxuan Cai
- Department of Medicine and Cardiovascular Research Center, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Songhua Li
- Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Hector H. Valdivia
- Department of Medicine and Cardiovascular Research Center, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Centre, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
34
|
Wang W, Lu D, Xu Q, Jin Y, Pang G, Liu Y. Remodeling of the ryanodine receptor isoform 1 channel regulates the sweet and umami taste perception of Rattus norvegicus. FUNDAMENTAL RESEARCH 2023; 3:459-468. [PMID: 38933774 PMCID: PMC11197482 DOI: 10.1016/j.fmre.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 02/22/2022] [Accepted: 02/28/2022] [Indexed: 10/18/2022] Open
Abstract
Sweet and umami tastes are elicited by sweet and umami receptors on the tongue and palate epithelium, respectively. However, the molecular machinery allowing the taste reaction remains incompletely understood. Through a phosphoproteomic approach, we identified the key proteins that trigger taste mechanisms based on phosphorylation cascades. Ryanodine receptor isoform 1 (RYR1) was further verified by sensory and behavioral assays. We propose a model of RYR1-mediated sweet/umami signaling in which the RYR1 channel, which mediates Ca2+ release from the endoplasmic reticulum, is closed by dephosphorylation in bud tissue after sweet/umami treatment. The alteration in Ca2+ content in the cytosol induces transient membrane depolarization and generates a cell current for taste signal transduction. We demonstrate that RYR1 is a new channel involved in the regulation of sweet/umami signal transduction and propose a "metabolic clock" notion based on sweet/umami sensing. Our study provides a valuable foundation for a system-level understanding of the taste perception mechanism.
Collapse
Affiliation(s)
- Wenli Wang
- Department of Food Science & Technology, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dingqiang Lu
- College of Biotechnology & Food Science, Tianjin University of Commerce, Tianjin 300134, China
| | - Qiuda Xu
- College of Biotechnology & Food Science, Tianjin University of Commerce, Tianjin 300134, China
| | - Yulian Jin
- College of Biotechnology & Food Science, Tianjin University of Commerce, Tianjin 300134, China
| | - Guangchang Pang
- College of Biotechnology & Food Science, Tianjin University of Commerce, Tianjin 300134, China
| | - Yuan Liu
- Department of Food Science & Technology, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| |
Collapse
|
35
|
Chen M, Toader B, Lederman R. Integrating Molecular Models Into CryoEM Heterogeneity Analysis Using Scalable High-resolution Deep Gaussian Mixture Models. J Mol Biol 2023; 435:168014. [PMID: 36806476 PMCID: PMC10164680 DOI: 10.1016/j.jmb.2023.168014] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/17/2023]
Abstract
Resolving the structural variability of proteins is often key to understanding the structure-function relationship of those macromolecular machines. Single particle analysis using Cryogenic electron microscopy (CryoEM), combined with machine learning algorithms, provides a way to reveal the dynamics within the protein system from noisy micrographs. Here, we introduce an improved computational method that uses Gaussian mixture models for protein structure representation and deep neural networks for conformation space embedding. By integrating information from molecular models into the heterogeneity analysis, we can analyze continuous protein conformational changes using structural information at the frequency of 1/3 Å-1, and present the results in a more interpretable form.
Collapse
Affiliation(s)
- Muyuan Chen
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, USA
| | - Bogdan Toader
- Department of Statistics and Data Science, Yale University, New Haven, CT, USA
| | - Roy Lederman
- Department of Statistics and Data Science, Yale University, New Haven, CT, USA
| |
Collapse
|
36
|
MATSUKAWA HIROYUKI, MURAYAMA TAKASHI. Development of Ryanodine Receptor (RyR) Inhibitors for Skeletal Muscle and Heart Diseases. JUNTENDO IJI ZASSHI = JUNTENDO MEDICAL JOURNAL 2023; 69:180-187. [PMID: 38855953 PMCID: PMC11153067 DOI: 10.14789/jmj.jmj22-0045-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/13/2023] [Indexed: 06/11/2024]
Abstract
Ryanodine receptors (RyR) are intracellular calcium (Ca2+) release channels on the sarcoplasmic reticulum of skeletal and cardiac muscles that play a central role in excitation-contraction coupling. Genetic mutations or posttranslational modifications of RyR causes hyperactivation of the channel, leading to various skeletal muscle and heart diseases. Currently, no specific treatments exist for most RyR-associated diseases. Recently, high-throughput screening (HTS) assays have been developed to identify potential candidates for treating RyR-related muscle diseases. These assays have successfully identified several compounds as novel RyR inhibitors, which are effective in animal models. In this review, we will focus on recent progress in HTS assays and discuss future perspectives of these promising approaches.
Collapse
Affiliation(s)
| | - TAKASHI MURAYAMA
- Corresponding author: Takashi Murayama, Department of Pharmacology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan, TEL: +81-3-5802-1035 E-mail: Research of the 4th Alumni Scientific Award for Medical Student, Juntendo University School of Medicine
| |
Collapse
|
37
|
Murayama T, Kurebayashi N, Ishida R, Kagechika H. Drug development for the treatment of RyR1-related skeletal muscle diseases. Curr Opin Pharmacol 2023; 69:102356. [PMID: 36842386 DOI: 10.1016/j.coph.2023.102356] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 02/27/2023]
Abstract
Type 1 ryanodine receptor (RyR1) is an intracellular Ca2+ release channel on the sarcoplasmic reticulum of skeletal muscle, and it plays a central role in excitation-contraction (E-C) coupling. Mutations in RyR1 are implicated in various muscle diseases including malignant hyperthermia, central core disease, and myopathies. Currently, no specific treatment exists for most of these diseases. Recently, high-throughput screening (HTS) assays have been developed for identifying potential candidates for treating RyR-related muscle diseases. Currently, two different methods, namely a FRET-based assay and an endoplasmic reticulum Ca2+-based assay, are available. These assays identified several compounds as novel RyR1 inhibitors. In addition, the development of a reconstituted platform permitted HTS assays for E-C coupling modulators. In this review, we will focus on recent progress in HTS assays and discuss future perspectives of these promising approaches.
Collapse
Affiliation(s)
- Takashi Murayama
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan.
| | - Nagomi Kurebayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Ryosuke Ishida
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroyuki Kagechika
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| |
Collapse
|
38
|
Ruiz-Fernández I, Valadés D, Dominguez R, Ferragut C, Pérez-López A. Load and muscle group size influence the ergogenic effect of acute caffeine intake in muscular strength, power and endurance. Eur J Nutr 2023; 62:1783-1794. [PMID: 36840816 DOI: 10.1007/s00394-023-03109-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 01/31/2023] [Indexed: 02/26/2023]
Abstract
INTRODUCTION Although acute caffeine intake seems to improve muscular strength-power-endurance performance, there is scarce evidence evaluating upper vs lower-body exercises at different loads. Thus, this study aimed to examine the effects of acute caffeine intake on upper and lower-body muscular strength, power and endurance performance at different loads. METHODS Twenty resistance-trained athletes (male/female: 10/10; age: 23 ± 4 years; body mass: 70.6 ± 15.1) participated in a double-blind, placebo-controlled, cross-over and randomized study. Participants were provided with either 3 mg/kg of body mass of caffeine or maltodextrin (placebo). Sixty minutes after ingestion, they performed muscular strength and power assessment for bench press and back squat exercise at 25%, 50%, 75% and 90% 1-repetition-maximum (1RM), performing 3, 2, 1 and 1 repetitions respectively, followed by muscular endurance assessment for both exercises at 65% and 85% 1RM performing until task failure. Isometric handgrip, isometric mid-thigh pull and vertical jump tests were also performed. RESULTS In muscular strength and power, compared to placebo, caffeine improved mean velocity (P = 0.045; pη2 = 0.101), mean power (P = 0.049; pη2 = 0.189) and rate of force development (RFD, P = 0.032; pη2 = 0.216), particularly in back squat exercise at 75% and 90% 1RM where mean velocity increased by 5-7% (P = 0.48-0.038; g = 0.348-1.413), mean power by 6-8% (P = 0.050-0.032; g = 0.547-0.818) and RFD by 17-97% (P = 0.042-0.046; g = 1.436-1.196). No differences were found in bench press exercise. In muscular endurance, caffeine improved the number of repetitions in all exercises and loads (P = 0.003; pη2 = 0.206), but only in back squat exercise at 85% 1RM, caffeine increased mean and peak velocity (8-9%, P = 0.006-0.004; g = 2.029-2.075), mean and peak power (10-13%, P = 0.006-0.003; g = 0.888-1.151) and force peak (3%, P = 0.009; g = 0.247). CONCLUSIONS Acute caffeine intake (3 mg/kg) improved muscular strength, power and endurance performance, revealing a more pronounced effect at high-loads (≥ 75% 1RM) and in lower-body (back squat) than in upper-body exercise (bench press) according to muscle group size.
Collapse
Affiliation(s)
- Iván Ruiz-Fernández
- Universidad de Alcalá, Facultad de Medicina y Ciencias de la Salud, Departamento de Ciencias Biomédicas, Área de Educación Física y Deportiva, Ctra. Madrid-Barcelona km 33,600, 28871, Alcalá de Henares, Spain
| | - David Valadés
- Universidad de Alcalá, Facultad de Medicina y Ciencias de la Salud, Departamento de Ciencias Biomédicas, Área de Educación Física y Deportiva, Ctra. Madrid-Barcelona km 33,600, 28871, Alcalá de Henares, Spain
| | - Raúl Dominguez
- Departamento de Motricidad Humana y Rendimiento Deportivo, Universidad de Sevilla, Seville, Spain
| | - Carmen Ferragut
- Universidad de Alcalá, Facultad de Medicina y Ciencias de la Salud, Departamento de Ciencias Biomédicas, Área de Educación Física y Deportiva, Ctra. Madrid-Barcelona km 33,600, 28871, Alcalá de Henares, Spain.
| | - Alberto Pérez-López
- Universidad de Alcalá, Facultad de Medicina y Ciencias de la Salud, Departamento de Ciencias Biomédicas, Área de Educación Física y Deportiva, Ctra. Madrid-Barcelona km 33,600, 28871, Alcalá de Henares, Spain
| |
Collapse
|
39
|
Mueller BD, Merrill SA, Watanabe S, Liu P, Niu L, Singh A, Maldonado-Catala P, Cherry A, Rich MS, Silva M, Maricq AV, Wang ZW, Jorgensen EM. CaV1 and CaV2 calcium channels mediate the release of distinct pools of synaptic vesicles. eLife 2023; 12:e81407. [PMID: 36820519 PMCID: PMC10023163 DOI: 10.7554/elife.81407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 02/22/2023] [Indexed: 02/24/2023] Open
Abstract
Activation of voltage-gated calcium channels at presynaptic terminals leads to local increases in calcium and the fusion of synaptic vesicles containing neurotransmitter. Presynaptic output is a function of the density of calcium channels, the dynamic properties of the channel, the distance to docked vesicles, and the release probability at the docking site. We demonstrate that at Caenorhabditis elegans neuromuscular junctions two different classes of voltage-gated calcium channels, CaV2 and CaV1, mediate the release of distinct pools of synaptic vesicles. CaV2 channels are concentrated in densely packed clusters ~250 nm in diameter with the active zone proteins Neurexin, α-Liprin, SYDE, ELKS/CAST, RIM-BP, α-Catulin, and MAGI1. CaV2 channels are colocalized with the priming protein UNC-13L and mediate the fusion of vesicles docked within 33 nm of the dense projection. CaV2 activity is amplified by ryanodine receptor release of calcium from internal stores, triggering fusion up to 165 nm from the dense projection. By contrast, CaV1 channels are dispersed in the synaptic varicosity, and are colocalized with UNC-13S. CaV1 and ryanodine receptors are separated by just 40 nm, and vesicle fusion mediated by CaV1 is completely dependent on the ryanodine receptor. Distinct synaptic vesicle pools, released by different calcium channels, could be used to tune the speed, voltage-dependence, and quantal content of neurotransmitter release.
Collapse
Affiliation(s)
- Brian D Mueller
- Howard Hughes Medical Institute, School of Biological Sciences, University of UtahSalt Lake CityUnited States
| | - Sean A Merrill
- Howard Hughes Medical Institute, School of Biological Sciences, University of UtahSalt Lake CityUnited States
| | - Shigeki Watanabe
- Howard Hughes Medical Institute, School of Biological Sciences, University of UtahSalt Lake CityUnited States
| | - Ping Liu
- Department of Neuroscience, University of Connecticut Medical SchoolFarmingtonUnited States
| | - Longgang Niu
- Department of Neuroscience, University of Connecticut Medical SchoolFarmingtonUnited States
| | - Anish Singh
- Howard Hughes Medical Institute, School of Biological Sciences, University of UtahSalt Lake CityUnited States
| | | | - Alex Cherry
- Howard Hughes Medical Institute, School of Biological Sciences, University of UtahSalt Lake CityUnited States
| | - Matthew S Rich
- Howard Hughes Medical Institute, School of Biological Sciences, University of UtahSalt Lake CityUnited States
| | - Malan Silva
- Howard Hughes Medical Institute, School of Biological Sciences, University of UtahSalt Lake CityUnited States
| | | | - Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut Medical SchoolFarmingtonUnited States
| | - Erik M Jorgensen
- Howard Hughes Medical Institute, School of Biological Sciences, University of UtahSalt Lake CityUnited States
| |
Collapse
|
40
|
Schackert F, Biedermann J, Abdolvand S, Minniberger S, Song C, Plested AJR, Carloni P, Sun H. Mechanism of Calcium Permeation in a Glutamate Receptor Ion Channel. J Chem Inf Model 2023; 63:1293-1300. [PMID: 36758214 PMCID: PMC9976283 DOI: 10.1021/acs.jcim.2c01494] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are neurotransmitter-activated cation channels ubiquitously expressed in vertebrate brains. The regulation of calcium flux through the channel pore by RNA-editing is linked to synaptic plasticity while excessive calcium influx poses a risk for neurodegeneration. Unfortunately, the molecular mechanisms underlying this key process are mostly unknown. Here, we investigated calcium conduction in calcium-permeable AMPAR using Molecular Dynamics (MD) simulations with recently introduced multisite force-field parameters for Ca2+. Our calculations are consistent with experiment and explain the distinct calcium permeability in different RNA-edited forms of GluA2. For one of the identified metal binding sites, multiscale Quantum Mechanics/Molecular Mechanics (QM/MM) simulations further validated the results from MD and revealed small but reproducible charge transfer between the metal ion and its first solvation shell. In addition, the ion occupancy derived from MD simulations independently reproduced the Ca2+ binding profile in an X-ray structure of an NaK channel mimicking the AMPAR selectivity filter. This integrated study comprising X-ray crystallography, multisite MD, and multiscale QM/MM simulations provides unprecedented insights into Ca2+ permeation mechanisms in AMPARs, and paves the way for studying other biological processes in which Ca2+ plays a pivotal role.
Collapse
Affiliation(s)
- Florian
Karl Schackert
- Computational
Biomedicine (IAS-5/INM-9), Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany,Department
of Physics, RWTH Aachen University, 52062 Aachen, Germany
| | - Johann Biedermann
- Institute
of Biology, Cellular Biophysics, Humboldt
Universität zu Berlin, 10115 Berlin, Germany,Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Saeid Abdolvand
- Institute
of Biology, Cellular Biophysics, Humboldt
Universität zu Berlin, 10115 Berlin, Germany,Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Sonja Minniberger
- Institute
of Biology, Cellular Biophysics, Humboldt
Universität zu Berlin, 10115 Berlin, Germany,Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Chen Song
- Center
for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China,Peking-Tsinghua
Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Andrew J. R. Plested
- Institute
of Biology, Cellular Biophysics, Humboldt
Universität zu Berlin, 10115 Berlin, Germany,Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Paolo Carloni
- Computational
Biomedicine (IAS-5/INM-9), Forschungszentrum
Jülich GmbH, 52428 Jülich, Germany,Department
of Physics, RWTH Aachen University, 52062 Aachen, Germany,
| | - Han Sun
- Leibniz
Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany,Institute
of Chemistry, TU Berlin, Straße des 17 Juni 135, 10623 Berlin, Germany,
| |
Collapse
|
41
|
Iyer KA, Barnakov V, Samsó M. Three-dimensional perspective on ryanodine receptor mutations causing skeletal and cardiac muscle-related diseases. Curr Opin Pharmacol 2023; 68:102327. [PMID: 36516687 PMCID: PMC9908851 DOI: 10.1016/j.coph.2022.102327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/18/2022] [Accepted: 11/12/2022] [Indexed: 12/14/2022]
Abstract
Mutations in RyR alter the cell's Ca2+ homeostasis and can cause serious health problems for which few effective therapies are available. Until recently, there was little structural context for the hundreds of mutations linked to muscular disorders reported for this large channel. Growing knowledge of the three-dimensional structure of RyR starts to illustrate the fine control of Ca2+ release. Current efforts directed towards understanding how disease mutations impinge in such processes will be crucial for future design of novel therapies. In this review article we discuss the up-to-date information about mutations according to their role in the 3D structure, and classified them to provide context from a structural perspective.
Collapse
Affiliation(s)
- Kavita A Iyer
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Vadim Barnakov
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Montserrat Samsó
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.
| |
Collapse
|
42
|
Abstract
This Review provides an update on ryanodine receptors (RyRs) and their role in human diseases of heart, muscle, and brain. Calcium (Ca2+) is a requisite second messenger in all living organisms. From C. elegans to mammals, Ca2+ is necessary for locomotion, bodily functions, and neural activity. However, too much of a good thing can be bad. Intracellular Ca2+ overload can result in loss of function and death. Intracellular Ca2+ release channels evolved to safely provide large, rapid Ca2+ signals without exposure to toxic extracellular Ca2+. RyRs are intracellular Ca2+ release channels present throughout the zoosphere. Over the past 35 years, our knowledge of RyRs has advanced to the level of atomic-resolution structures revealing their role in the mechanisms underlying the pathogenesis of human disorders of heart, muscle, and brain. Stress-induced RyR-mediated intracellular Ca2+ leak in the heart can promote heart failure and cardiac arrhythmias. In skeletal muscle, RyR1 leak contributes to muscle weakness in inherited myopathies, to age-related loss of muscle function and cancer-associated muscle weakness, and to impaired muscle function in muscular dystrophies, including Duchenne. In the brain, leaky RyR channels contribute to cognitive dysfunction in Alzheimer's disease, posttraumatic stress disorder, and Huntington's disease. Novel therapeutics targeting dysfunctional RyRs are showing promise.
Collapse
|
43
|
Greene D, Luchko T, Shiferaw Y. The role of subunit cooperativity on ryanodine receptor 2 calcium signaling. Biophys J 2023; 122:215-229. [PMID: 36348625 PMCID: PMC9822801 DOI: 10.1016/j.bpj.2022.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/09/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
The ryanodine receptor type 2 (RyR2) is composed of four subunits that control calcium (Ca) release in cardiac cells. RyR2 serves primarily as a Ca sensor and can respond to rapid sub-millisecond pulses of Ca while remaining shut at resting concentrations. However, it is not known how the four subunits interact for the RyR2 to function as an effective Ca sensor. To address this question, and to understand the role of subunit cooperativity in Ca-mediated signal transduction, we have developed a computational model of the RyR2 composed of four interacting subunits. We first analyze the statistical properties of a single RyR2 tetramer, where each subunit can exist in a closed or open conformation. Our findings indicate that the number of subunits in the open state is a crucial parameter that dictates RyR2 kinetics. We find that three or four open subunits are required for the RyR2 to harness cooperative interactions to respond to sub-millisecond changes in Ca, while at the same time remaining shut at the resting Ca levels in the cardiac cell. If the required number of open subunits is lowered to one or two, the RyR2 cannot serve as a robust Ca sensor, as the large cooperativity required to stabilize the closed state prevents channel activation. Using this four-subunit model, we analyze the kinetics of Ca release from a RyR2 cluster. We show that the closure of a cluster of RyR2 channels is highly sensitive to the balance of cooperative interactions between closed and open subunits. Based on this result, we analyze how specific interactions between RyR2 subunits can induce persistent Ca leak from the sarcoplasmic reticulum (SR), which is believed to be arrhythmogenic. Thus, these results provide a framework to analyze how a pharmacologic or genetic modification of RyR2 subunit cooperativity can induce abnormal Ca cycling that can potentially lead to life-threatening arrhythmias.
Collapse
Affiliation(s)
- D'Artagnan Greene
- Department of Physics & Astronomy, California State University, Northridge
| | - Tyler Luchko
- Department of Physics & Astronomy, California State University, Northridge
| | - Yohannes Shiferaw
- Department of Physics & Astronomy, California State University, Northridge.
| |
Collapse
|
44
|
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.
Collapse
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
| |
Collapse
|
45
|
Neumann J, Van Nieuwenhove E, Terry LE, Staels F, Knebel TR, Welkenhuyzen K, Ahmadzadeh K, Baker MR, Gerbaux M, Willemsen M, Barber JS, Serysheva II, De Waele L, Vermeulen F, Schlenner S, Meyts I, Yule DI, Bultynck G, Schrijvers R, Humblet-Baron S, Liston A. Disrupted Ca 2+ homeostasis and immunodeficiency in patients with functional IP 3 receptor subtype 3 defects. Cell Mol Immunol 2023; 20:11-25. [PMID: 36302985 PMCID: PMC9794825 DOI: 10.1038/s41423-022-00928-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 09/12/2022] [Indexed: 11/27/2022] Open
Abstract
Calcium signaling is essential for lymphocyte activation, with genetic disruptions of store-operated calcium (Ca2+) entry resulting in severe immunodeficiency. The inositol 1,4,5-trisphosphate receptor (IP3R), a homo- or heterotetramer of the IP3R1-3 isoforms, amplifies lymphocyte signaling by releasing Ca2+ from endoplasmic reticulum stores following antigen stimulation. Although knockout of all IP3R isoforms in mice causes immunodeficiency, the seeming redundancy of the isoforms is thought to explain the absence of variants in human immunodeficiency. In this study, we identified compound heterozygous variants of ITPR3 (a gene encoding IP3R subtype 3) in two unrelated Caucasian patients presenting with immunodeficiency. To determine whether ITPR3 variants act in a nonredundant manner and disrupt human immune responses, we characterized the Ca2+ signaling capacity, the lymphocyte response, and the clinical phenotype of these patients. We observed disrupted Ca2+ signaling in patient-derived fibroblasts and immune cells, with abnormal proliferation and activation responses following T-cell receptor stimulation. Reconstitution of IP3R3 in IP3R knockout cell lines led to the identification of variants as functional hypomorphs that showed reduced ability to discriminate between homeostatic and induced states, validating a genotype-phenotype link. These results demonstrate a functional link between defective endoplasmic reticulum Ca2+ channels and immunodeficiency and identify IP3Rs as diagnostic targets for patients with specific inborn errors of immunity. These results also extend the known cause of Ca2+-associated immunodeficiency from store-operated entry to impaired Ca2+ mobilization from the endoplasmic reticulum, revealing a broad sensitivity of lymphocytes to genetic defects in Ca2+ signaling.
Collapse
Affiliation(s)
- Julika Neumann
- VIB Center for Brain and Disease Research, Leuven, Belgium
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | - Erika Van Nieuwenhove
- VIB Center for Brain and Disease Research, Leuven, Belgium
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
- UZ Leuven, Leuven, Belgium
| | - Lara E Terry
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, 14526, USA
| | - Frederik Staels
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
- UZ Leuven, Leuven, Belgium
| | - Taylor R Knebel
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, 14526, USA
| | - Kirsten Welkenhuyzen
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kankerinstituut, KU Leuven, Leuven, Belgium
| | - Kourosh Ahmadzadeh
- Laboratory of Immunobiology, Department Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium
| | - Mariah R Baker
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Margaux Gerbaux
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
- Pediatric Department, Academic Children Hospital Queen Fabiola, Université Libre de Bruxelles, Brussels, Belgium
| | - Mathijs Willemsen
- VIB Center for Brain and Disease Research, Leuven, Belgium
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | - John S Barber
- VIB Center for Brain and Disease Research, Leuven, Belgium
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | - Irina I Serysheva
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Liesbeth De Waele
- Department of Pediatric Neurology, University Hospitals Leuven, Leuven, Belgium
| | | | - Susan Schlenner
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | - Isabelle Meyts
- UZ Leuven, Leuven, Belgium.
- Laboratory for Inborn Errors of Immunity, Department of Immunology and Microbiology, KU Leuven, Leuven, Belgium.
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, 14526, USA
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kankerinstituut, KU Leuven, Leuven, Belgium
| | - Rik Schrijvers
- UZ Leuven, Leuven, Belgium.
- Laboratory for Allergy and Clinical Immunology and Immunogenetics Research Group, Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium.
| | | | - Adrian Liston
- VIB Center for Brain and Disease Research, Leuven, Belgium.
- Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
- Immunology Programme, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK.
| |
Collapse
|
46
|
O’Connor TN, van den Bersselaar LR, Chen YS, Nicolau S, Simon B, Huseth A, Todd JJ, Van Petegem F, Sarkozy A, Goldberg MF, Voermans NC, Dirksena RT. RYR-1-Related Diseases International Research Workshop: From Mechanisms to Treatments Pittsburgh, PA, U.S.A., 21-22 July 2022. J Neuromuscul Dis 2023; 10:135-154. [PMID: 36404556 PMCID: PMC10023165 DOI: 10.3233/jnd-221609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Thomas N. O’Connor
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Luuk R. van den Bersselaar
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Malignant Hyperthermia Investigation Unit, Department of Anaesthesia, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands
| | - Yu Seby Chen
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Stefan Nicolau
- Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | | | | | - Joshua J. Todd
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Anna Sarkozy
- The Dubowitz Neuromuscular Centre, Institute of Child Health and Great Ormond Street Hospital for Children, London, UK
| | | | - Nicol C. Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Robert T. Dirksena
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | | |
Collapse
|
47
|
Wang ZW, Riaz S, Niu L. Roles and Sources of Calcium in Synaptic Exocytosis. ADVANCES IN NEUROBIOLOGY 2023; 33:139-170. [PMID: 37615866 DOI: 10.1007/978-3-031-34229-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Calcium ions (Ca2+) play a critical role in triggering neurotransmitter release. The rate of release is directly related to the concentration of Ca2+ at the presynaptic site, with a supralinear relationship. There are two main sources of Ca2+ that trigger synaptic vesicle fusion: influx through voltage-gated Ca2+ channels in the plasma membrane and release from the endoplasmic reticulum via ryanodine receptors. This chapter will cover the sources of Ca2+ at the presynaptic nerve terminal, the relationship between neurotransmitter release rate and Ca2+ concentration, and the mechanisms that achieve the necessary Ca2+ concentrations for triggering synaptic exocytosis at the presynaptic site.
Collapse
Affiliation(s)
- Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA.
| | - Sadaf Riaz
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Longgang Niu
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
| |
Collapse
|
48
|
Chen YS, Van Petegem F. Structural and functional conservation of the activating Ca 2+ binding site in inositol 1,4.5-trisphosphate and ryanodine receptors. Cell Calcium 2022; 108:102671. [PMID: 36370621 DOI: 10.1016/j.ceca.2022.102671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/06/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) and Ryanodine Receptors (RyRs) dictate the release of Ca2+ from the Endoplasmic (ER) and Sarcoplasmic Reticulum (SR). Arige et al [1] investigated the functional importance of specific Ca2+-coordinating residues, unambiguously confirming the activating Ca2+ binding site in the IP3R.
Collapse
Affiliation(s)
- Yu Seby Chen
- Department of Biochemistry and Molecular Biology, University of British Columbia, Life Sciences Institute, 2350 Health Sciences Mall, V6T 1Z3 Vancouver, BC Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Life Sciences Institute, 2350 Health Sciences Mall, V6T 1Z3 Vancouver, BC Canada.
| |
Collapse
|
49
|
Hadiatullah H, Zhang Y, Samurkas A, Xie Y, Sundarraj R, Zuilhof H, Qiao J, Yuchi Z. Recent progress in the structural study of ion channels as insecticide targets. INSECT SCIENCE 2022; 29:1522-1551. [PMID: 35575601 DOI: 10.1111/1744-7917.13032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 02/07/2022] [Accepted: 02/21/2022] [Indexed: 06/15/2023]
Abstract
Ion channels, many expressed in insect neural and muscular systems, have drawn huge attention as primary targets of insecticides. With the recent technical breakthroughs in structural biology, especially in cryo-electron microscopy (cryo-EM), many new high-resolution structures of ion channel targets, apo or in complex with insecticides, have been solved, shedding light on the molecular mechanism of action of the insecticides and resistance mutations. These structures also provide accurate templates for structure-based insecticide screening and rational design. This review summarizes the recent progress in the structural studies of 5 ion channel families: the ryanodine receptor (RyR), the nicotinic acetylcholine receptor (nAChR), the voltage-gated sodium channel (VGSC), the transient receptor potential (TRP) channel, and the ligand-gated chloride channel (LGCC). We address the selectivity of the channel-targeting insecticides by examining the conservation of key coordinating residues revealed by the structures. The possible resistance mechanisms are proposed based on the locations of the identified resistance mutations on the 3D structures of the target channels and their impacts on the binding of insecticides. Finally, we discuss how to develop "green" insecticides with a novel mode of action based on these high-resolution structures to overcome the resistance.
Collapse
Affiliation(s)
- Hadiatullah Hadiatullah
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Yongliang Zhang
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Arthur Samurkas
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Laboratory of Organic Chemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Yunxuan Xie
- Department of Environmental Science, Tianjin University, Tianjin, China
| | - Rajamanikandan Sundarraj
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Han Zuilhof
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Laboratory of Organic Chemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Jianjun Qiao
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, Tianjin Medical University Cancer Institute & Hospital; National Clinical Research Center for Cancer; Key Laboratory of Cancer Prevention and Therapy, Tianjin; Tianjin's Clinical Research Center for Cancer, Tianjin, China
| |
Collapse
|
50
|
Greene D, Barton M, Luchko T, Shiferaw Y. Molecular Dynamics Simulations of the Cardiac Ryanodine Receptor Type 2 (RyR2) Gating Mechanism. J Phys Chem B 2022; 126:9790-9809. [PMID: 36384028 PMCID: PMC9720719 DOI: 10.1021/acs.jpcb.2c03031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mutations in the cardiac ryanodine receptor type 2 (RyR2) have been linked to fatal cardiac arrhythmias such as catecholaminergic polymorphic ventricular tachycardia (CPVT). While many CPVT mutations are associated with an increase in Ca2+ leak from the sarcoplasmic reticulum, the mechanistic details of RyR2 channel gating are not well understood, and this poses a barrier in the development of new pharmacological treatments. To address this, we explore the gating mechanism of the RyR2 using molecular dynamics (MD) simulations. We test the effect of changing the conformation of certain structural elements by constructing chimera RyR2 structures that are derived from the currently available closed and open cryo-electron microscopy (cryo-EM) structures, and we then use MD simulations to relax the system. Our key finding is that the position of the S4-S5 linker (S4S5L) on a single subunit can determine whether the channel as a whole is open or closed. Our analysis reveals that the position of the S4S5L is regulated by interactions with the U-motif on the same subunit and with the S6 helix on an adjacent subunit. We find that, in general, channel gating is crucially dependent on high percent occupancy interactions between adjacent subunits. We compare our interaction analysis to 49 CPVT1 mutations in the literature and find that 73% appear near a high percent occupancy interaction between adjacent subunits. This suggests that disruption of cooperative, high percent occupancy interactions between adjacent subunits is a primary cause of channel leak and CPVT in mutant RyR2 channels.
Collapse
|