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Almomen M, Burgon PG. Why Craniofacial Surgeons/Researchers Need to be Aware of Native American Myopathy? Neuropediatrics 2024; 55:149-155. [PMID: 38378040 DOI: 10.1055/a-2271-8619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Congenital myopathy type 13 (CMYO13), also known as Native American myopathy, is a rare muscle disease characterized by early-onset hypotonia, muscle weakness, delayed motor milestones, and susceptibility to malignant hyperthermia. The phenotypic spectrum of congenital myopathy type 13 is expanding, with milder forms reported in non-native American patients. The first description of the disease dates to 1987 when Bailey and Bloch described an infant belonging to a Native American tribe with cleft palate, micrognathia, arthrogryposis, and general-anesthesia-induced malignant hyperthermia reaction; the cause of the latter remains poorly defined in this rare disease. The pan-ethnic distribution, as well as its predisposition to malignant hyperthermia, makes the identification of CMYO13 essential to avoid life-threatening, anesthesia-related complications. In this article, we are going to review the clinical phenotype of this disease and the pathophysiology of this rare disease with a focus on two unique features of the disease, namely cleft palate and malignant hyperthermia. We also highlight the importance of recognizing this disease's expanding phenotypic spectrum-including its susceptibility to malignant hyperthermia-and providing appropriate care to affected individuals and families.
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Affiliation(s)
- Momen Almomen
- Department of Neurosciences, King Fahad Specialist Hospital, Dammam, Kingdom of Saudi Arabia
| | - Patrick G Burgon
- Department of Chemistry and Earth Sciences, College of Arts and Sciences, Qatar University, State of Qatar
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2
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Qu H, Mao M, Wang K, Mu Z, Hu B. Knockdown of ADAM8 inhibits the proliferation, migration, invasion, and tumorigenesis of renal clear cell carcinoma cells to enhance the immunotherapy efficacy. Transl Res 2024; 266:32-48. [PMID: 37992987 DOI: 10.1016/j.trsl.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/13/2023] [Indexed: 11/24/2023]
Abstract
The current study performed bioinformatics and in vitro and in vivo experiments to explore the effects of ADAM8 on the malignant behaviors and immunotherapeutic efficacy of renal clear cell carcinoma (ccRCC) Cells. The modular genes most associated with immune cells were screened. Then, prognostic risk models were constructed by univariate COX analysis, LASSO regression analysis and multivariate COX analysis, and their diagnostic value was determined. The correlation between tumor mutation load (TMB) scores and the prognosis of ccRCC patients was clarified. Finally, six key genes (ABI3, ADAM8, APOL3, MX2, CCDC69, and STAC3) were analyzed for immunotherapy efficacy. Human and mouse ccRCC cell lines and human proximal tubular epithelial cell lines were used for in vitro cell experiments. The effect of ADAM8 overexpression or knockdown on tumor formation and survival in ccRCC cells was examined by constructing subcutaneous transplanted tumor model. Totally, 636 Black module genes were screened as being most associated with immune cell infiltration. Six genes were subsequently confirmed for the construction of prognostic risk models, of which ABI3, APOL3 and CCDC69 were low-risk factors, while ADAM8, MX2 and STAC3 were high-risk factors. The constructed risk model based on the identified six genes could accurately predict the prognosis of ccRCC patients. Besides, TMB was significantly associated with the prognosis of ccRCC patients. Furthermore, ABI3, ADAM8, APOL3, MX2, CCDC69 and STAC3 might play important roles in treatment concerning CTLA4 inhibitors or PD-1 inhibitors or combined inhibitors. Finally, we confirmed that ADAM8 could promote the proliferation, migration and invasion of ccRCC cells through in vitro experiments, and further found that in in vivo experiments, ADAM8 knockdown could inhibit tumor formation in ccRCC cells, improve the therapeutic effect of anti-PD1, and prolong the survival of mice. Our study highlighted the alleviative role of silencing ADAM8 in ccRCC patients.
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Affiliation(s)
- Hongchen Qu
- Department of Urological Surgery, Liaoning Cancer Hospital & Institute, Cancer Hospital of China Medical University, No.44 Xiaoheyan Road, Dadong District, Shenyang, Liaoning Province 110042, PR China
| | - Minghuan Mao
- Department of Urological Surgery, Fourth affiliated Hospital of China Medical University, Shenyang 110000, PR China
| | - Kai Wang
- Department of Urological Surgery, Liaoning Cancer Hospital & Institute, Cancer Hospital of China Medical University, No.44 Xiaoheyan Road, Dadong District, Shenyang, Liaoning Province 110042, PR China
| | - Zhongyi Mu
- Department of Urological Surgery, Liaoning Cancer Hospital & Institute, Cancer Hospital of China Medical University, No.44 Xiaoheyan Road, Dadong District, Shenyang, Liaoning Province 110042, PR China
| | - Bin Hu
- Department of Urological Surgery, Liaoning Cancer Hospital & Institute, Cancer Hospital of China Medical University, No.44 Xiaoheyan Road, Dadong District, Shenyang, Liaoning Province 110042, PR China.
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3
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Endo Y, Groom L, Wang SM, Pannia E, Griffiths NW, Van Gennip JLM, Ciruna B, Laporte J, Dirksen RT, Dowling JJ. Two zebrafish cacna1s loss-of-function variants provide models of mild and severe CACNA1S-related myopathy. Hum Mol Genet 2024; 33:254-269. [PMID: 37930228 PMCID: PMC10800018 DOI: 10.1093/hmg/ddad178] [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: 07/03/2023] [Revised: 09/25/2023] [Accepted: 10/09/2023] [Indexed: 11/07/2023] Open
Abstract
CACNA1S-related myopathy, due to pathogenic variants in the CACNA1S gene, is a recently described congenital muscle disease. Disease associated variants result in loss of gene expression and/or reduction of Cav1.1 protein stability. There is an incomplete understanding of the underlying disease pathomechanisms and no effective therapies are currently available. A barrier to the study of this myopathy is the lack of a suitable animal model that phenocopies key aspects of the disease. To address this barrier, we generated knockouts of the two zebrafish CACNA1S paralogs, cacna1sa and cacna1sb. Double knockout fish exhibit severe weakness and early death, and are characterized by the absence of Cav1.1 α1 subunit expression, abnormal triad structure, and impaired excitation-contraction coupling, thus mirroring the severe form of human CACNA1S-related myopathy. A double mutant (cacna1sa homozygous, cacna1sb heterozygote) exhibits normal development, but displays reduced body size, abnormal facial structure, and cores on muscle pathologic examination, thus phenocopying the mild form of human CACNA1S-related myopathy. In summary, we generated and characterized the first cacna1s zebrafish loss-of-function mutants, and show them to be faithful models of severe and mild forms of human CACNA1S-related myopathy suitable for future mechanistic studies and therapy development.
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Affiliation(s)
- Yukari Endo
- Program for Genetics and Genome Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Linda Groom
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642, United States
| | - Sabrina M Wang
- Program for Genetics and Genome Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Emanuela Pannia
- Program for Genetics and Genome Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
- Zebrafish Genetics and Disease Models Core Facility, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Nigel W Griffiths
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Jenica L M Van Gennip
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Brian Ciruna
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm U1258, Cnrs UMR7104, Université de Strasbourg, 1 Rue Laurent Fries, Illkirch 67400, France
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642, United States
| | - James J Dowling
- Program for Genetics and Genome Biology, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
- Division of Neurology, Hospital for Sick Children, 555 University Ave, Toronto, ON M5G 1X8, Canada
- Department of Paediatrics, University of Toronto, 555 University Ave, Toronto, ON M5G 1X8, Canada
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4
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Bibollet H, Kramer A, Bannister RA, Hernández-Ochoa EO. Advances in Ca V1.1 gating: New insights into permeation and voltage-sensing mechanisms. Channels (Austin) 2023; 17:2167569. [PMID: 36642864 PMCID: PMC9851209 DOI: 10.1080/19336950.2023.2167569] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/09/2023] [Indexed: 01/17/2023] Open
Abstract
The CaV1.1 voltage-gated Ca2+ channel carries L-type Ca2+ current and is the voltage-sensor for excitation-contraction (EC) coupling in skeletal muscle. Significant breakthroughs in the EC coupling field have often been close on the heels of technological advancement. In particular, CaV1.1 was the first voltage-gated Ca2+ channel to be cloned, the first ion channel to have its gating current measured and the first ion channel to have an effectively null animal model. Though these innovations have provided invaluable information regarding how CaV1.1 detects changes in membrane potential and transmits intra- and inter-molecular signals which cause opening of the channel pore and support Ca2+ release from the sarcoplasmic reticulum remain elusive. Here, we review current perspectives on this topic including the recent application of functional site-directed fluorometry.
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Affiliation(s)
- Hugo Bibollet
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Audra Kramer
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Roger A. Bannister
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Erick O. Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
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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.
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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.
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6
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Mehrabipour M, Jasemi NSK, Dvorsky R, Ahmadian MR. A Systematic Compilation of Human SH3 Domains: A Versatile Superfamily in Cellular Signaling. Cells 2023; 12:2054. [PMID: 37626864 PMCID: PMC10453029 DOI: 10.3390/cells12162054] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/02/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
SRC homology 3 (SH3) domains are fundamental modules that enable the assembly of protein complexes through physical interactions with a pool of proline-rich/noncanonical motifs from partner proteins. They are widely studied modular building blocks across all five kingdoms of life and viruses, mediating various biological processes. The SH3 domains are also implicated in the development of human diseases, such as cancer, leukemia, osteoporosis, Alzheimer's disease, and various infections. A database search of the human proteome reveals the existence of 298 SH3 domains in 221 SH3 domain-containing proteins (SH3DCPs), ranging from 13 to 720 kilodaltons. A phylogenetic analysis of human SH3DCPs based on their multi-domain architecture seems to be the most practical way to classify them functionally, with regard to various physiological pathways. This review further summarizes the achievements made in the classification of SH3 domain functions, their binding specificity, and their significance for various diseases when exploiting SH3 protein modular interactions as drug targets.
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Affiliation(s)
- Mehrnaz Mehrabipour
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.M.); (N.S.K.J.)
| | - Neda S. Kazemein Jasemi
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.M.); (N.S.K.J.)
| | - Radovan Dvorsky
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.M.); (N.S.K.J.)
- Center for Interdisciplinary Biosciences, P. J. Šafárik University, 040 01 Košice, Slovakia
| | - Mohammad R. Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.M.); (N.S.K.J.)
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7
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Navarro-Martínez A, Vicente-García C, Carvajal JJ. NMJ-related diseases beyond the congenital myasthenic syndromes. Front Cell Dev Biol 2023; 11:1216726. [PMID: 37601107 PMCID: PMC10436495 DOI: 10.3389/fcell.2023.1216726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/21/2023] [Indexed: 08/22/2023] Open
Abstract
Neuromuscular junctions (NMJs) are a special type of chemical synapse that transmits electrical stimuli from motor neurons (MNs) to their innervating skeletal muscle to induce a motor response. They are an ideal model for the study of synapses, given their manageable size and easy accessibility. Alterations in their morphology or function lead to neuromuscular disorders, such as the congenital myasthenic syndromes, which are caused by mutations in proteins located in the NMJ. In this review, we highlight novel potential candidate genes that may cause or modify NMJs-related pathologies in humans by exploring the phenotypes of hundreds of mouse models available in the literature. We also underscore the fact that NMJs may differ between species, muscles or even sexes. Hence the importance of choosing a good model organism for the study of NMJ-related diseases: only taking into account the specific features of the mammalian NMJ, experimental results would be efficiently translated to the clinic.
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Affiliation(s)
| | - Cristina Vicente-García
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO-JA, Universidad Pablo de Olavide, Sevilla, Spain
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Campiglio M, Dyrda A, Tuinte WE, Török E. Ca V1.1 Calcium Channel Signaling Complexes in Excitation-Contraction Coupling: Insights from Channelopathies. Handb Exp Pharmacol 2023; 279:3-39. [PMID: 36592225 DOI: 10.1007/164_2022_627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the mechanical coupling between two ion channels: the L-type voltage-gated calcium channel (CaV1.1), located in the sarcolemma and functioning as the voltage sensor of EC coupling, and the ryanodine receptor 1 (RyR1), located on the sarcoplasmic reticulum serving as the calcium release channel. To this day, the molecular mechanism by which these two ion channels are linked remains elusive. However, recently, skeletal muscle EC coupling could be reconstituted in heterologous cells, revealing that only four proteins are essential for this process: CaV1.1, RyR1, and the cytosolic proteins CaVβ1a and STAC3. Due to the crucial role of these proteins in skeletal muscle EC coupling, any mutation that affects any one of these proteins can have devastating consequences, resulting in congenital myopathies and other pathologies.Here, we summarize the current knowledge concerning these four essential proteins and discuss the pathophysiology of the CaV1.1, RyR1, and STAC3-related skeletal muscle diseases with an emphasis on the molecular mechanisms. Being part of the same signalosome, mutations in different proteins often result in congenital myopathies with similar symptoms or even in the same disease.
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Affiliation(s)
- Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
| | - Agnieszka Dyrda
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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9
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Brooks SV, Guzman SD, Ruiz LP. Skeletal muscle structure, physiology, and function. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:3-16. [PMID: 37562874 DOI: 10.1016/b978-0-323-98818-6.00013-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Contractions of skeletal muscles provide the stability and power for all body movements. Consequently, any impairment in skeletal muscle function results in some degree of instability or immobility. Factors that influence skeletal muscle structure and function are therefore of great interest scientifically and clinically. Injury, neuromuscular disease, and old age are among the factors that commonly contribute to impairments in skeletal muscle function. The goal of this chapter is to summarize the fundamentals of skeletal muscle structure and function to provide foundational knowledge for this Handbook volume. We examine the molecular interactions that provide the basis for the generation of force and movement, discuss mechanisms of the regulation of contraction at the level of myofibers, and introduce concepts of the activation and control of muscle function in vivo. Where appropriate, the chapter updates the emerging science that will increase understanding of muscle function.
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Affiliation(s)
- Susan V Brooks
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, United States; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States.
| | - Steve D Guzman
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Lloyd P Ruiz
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
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Tan L, Teng Y, Yu H, Liu C, Xiao K, Yin J, Zuo Y, Zhu T, Deng X. Clinical Features of Suspected Malignant Hyperthermia in China from 2015 to 2020: A Retrospective Study from China Malignant Hyperthermia Emergency Assistance Group. J Multidiscip Healthc 2022; 15:3005-3013. [PMID: 36601426 PMCID: PMC9807132 DOI: 10.2147/jmdh.s387208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/25/2022] [Indexed: 12/30/2022] Open
Abstract
Purpose Malignant hyperthermia (MH) is a rare but fatal pharmacogenetic disorder, triggered by inhalational anesthetics or succinylcholine. Since the first nonprofit academic organization China Malignant Hyperthermia Emergency Assistance WeChat-based Group (CMHEA Group) was established in 2015, they have actively participated in the diagnosis and treatment of MH patients. Based on the CMHEA Group, the aim of the study was to retrospectively analyze the characteristics of suspected MH in China from 2015 to 2020. Methods We conducted a retrospective analysis of the suspected MH patients from 2015 to 2020, for analyzing the current clinical diagnosis, treatment and prognosis of MH in China. Results A total of 58 suspected MH cases occurred from 2015 to 2020, of these, 36 cases were collected with detailed data. The MH clinical grading score of 36 patients ranged from 33 to 73, with a median of 55. Abnormal hyperthermia and hypercarbia were the most common early signs of MH. Four patients were confirmed carrying six different potential MH-causative mutations. Of the total 58 cases, 14 patients (24.1%) received dantrolene and the whole mortality rate was 53.4%. Compared to the patients not receiving dantrolene treatment, the survival rate of patients receiving dantrolene treatment was significantly higher than that of patients not receiving dantrolene (78.6% vs 36.4%, p = 0.007). Conclusion The current main diagnostic methods of suspected MH in China are still clinical diagnosis. Hence, it is critical to keep dantrolene for immediate accessibility with the introduction of domestic dantrolene to China. The WeChat group model has played an important but limited role in quick diagnosis and treatment of MH.
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Affiliation(s)
- Lingcan Tan
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Yi Teng
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Hong Yu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Chunyuan Liu
- Department of Anesthesiology, Chongqing Liangping District People’s Hospital, Chongqing, 405200, People’s Republic of China
| | - Kun Xiao
- School of Information and Software Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, People’s Republic of China
| | - Jin Yin
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Yunxia Zuo
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China
| | - Xiaoqian Deng
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610041, People’s Republic of China,Correspondence: Xiaoqian Deng, Department of Anesthesiology, West China Hospital, Sichuan University, No. 37 Guoxue Alley, Chengdu, 610041, People’s Republic of China, Tel +86 885423592, Email
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11
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Murayama T, Kurebayashi N, Numaga-Tomita T, Kobayashi T, Okazaki S, Yamashiro K, Nakada T, Mori S, Ishida R, Kagechika H, Yamada M, Sakurai T. A reconstituted depolarization-induced Ca2+ release platform for validation of skeletal muscle disease mutations and drug discovery. J Gen Physiol 2022; 154:213630. [PMID: 36318155 PMCID: PMC9629852 DOI: 10.1085/jgp.202213230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/06/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022] Open
Abstract
In skeletal muscle excitation-contraction (E-C) coupling, depolarization of the plasma membrane triggers Ca2+ release from the sarcoplasmic reticulum (SR), referred to as depolarization-induced Ca2+ release (DICR). DICR occurs through the type 1 ryanodine receptor (RyR1), which physically interacts with the dihydropyridine receptor Cav1.1 subunit in specific machinery formed with additional essential components including β1a, Stac3 adaptor protein, and junctophilins. Exome sequencing has accelerated the discovery of many novel mutations in genes encoding DICR machinery in various skeletal muscle diseases. However, functional validation is time-consuming because it must be performed in a skeletal muscle environment. In this study, we established a platform of the reconstituted DICR in HEK293 cells. The essential components were effectively transduced into HEK293 cells expressing RyR1 using baculovirus vectors, and Ca2+ release was quantitatively measured with R-CEPIA1er, a fluorescent ER Ca2+ indicator, without contaminant of extracellular Ca2+ influx. In these cells, [K+]-dependent Ca2+ release was triggered by chemical depolarization with the aid of inward rectifying potassium channel, indicating a successful reconstitution of DICR. Using the platform, we evaluated several Cav1.1 mutations that are implicated in malignant hyperthermia and myopathy. We also tested several RyR1 inhibitors; whereas dantrolene and Cpd1 inhibited DICR, procaine had no effect. Furthermore, twitch potentiators such as perchlorate and thiocyanate shifted the voltage dependence of DICR to more negative potentials without affecting Ca2+-induced Ca2+ release. These results well reproduced the findings with the muscle fibers and the cultured myotubes. Since the procedure is simple and reproducible, the reconstituted DICR platform will be highly useful for the validation of mutations and drug discovery for skeletal muscle diseases.
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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
| | - Takuro Numaga-Tomita
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Takuya Kobayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Satoru Okazaki
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Kyosuke Yamashiro
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Tsutomu Nakada
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Shuichi Mori
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 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
| | - Mitsuhiko Yamada
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Takashi Sakurai
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
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12
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Tuinte WE, Török E, Mahlknecht I, Tuluc P, Flucher BE, Campiglio M. STAC3 determines the slow activation kinetics of Ca V 1.1 currents and inhibits its voltage-dependent inactivation. J Cell Physiol 2022; 237:4197-4214. [PMID: 36161458 DOI: 10.1002/jcp.30870] [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: 07/26/2022] [Accepted: 08/23/2022] [Indexed: 11/06/2022]
Abstract
The skeletal muscle CaV 1.1 channel functions as the voltage-sensor of excitation-contraction (EC) coupling. Recently, the adaptor protein STAC3 was found to be essential for both CaV 1.1 functional expression and EC coupling. Interestingly, STAC proteins were also reported to inhibit calcium-dependent inactivation (CDI) of L-type calcium channels (LTCC), an important negative feedback mechanism in calcium signaling. The same could not be demonstrated for CaV 1.1, as STAC3 is required for its functional expression. However, upon strong membrane depolarization, CaV 1.1 conducts calcium currents characterized by very slow kinetics of activation and inactivation. Therefore, we hypothesized that the negligible inactivation observed in CaV 1.1 currents reflects the inhibitory effect of STAC3. Here, we inserted a triple mutation in the linker region of STAC3 (ETLAAA), as the analogous mutation abolished the inhibitory effect of STAC2 on CDI of CaV 1.3 currents. When coexpressed in CaV 1.1/STAC3 double knockout myotubes, the mutant STAC3-ETLAAA failed to colocalize with CaV 1.1 in the sarcoplasmic reticulum/membrane junctions. However, combined patch-clamp and calcium recording experiments revealed that STAC3-ETLAAA supports CaV 1.1 functional expression and EC coupling, although at a reduced extent compared to wild-type STAC3. Importantly, STAC3-ETLAAA coexpression dramatically accelerated the kinetics of activation and inactivation of CaV 1.1 currents, suggesting that STAC3 determines the slow CaV 1.1 currents kinetics. To examine if STAC3 specifically inhibits the CDI of CaV 1.1 currents, we performed patch-clamp recordings using calcium and barium as charge carriers in HEK cells. While CaV 1.1 displayed negligible CDI with STAC3, this did not increase in the presence of STAC3-ETLAAA. On the contrary, our data demonstrate that STAC3 specifically inhibits the voltage-dependent inactivation (VDI) of CaV 1.1 currents. Altogether, these results designate STAC3 as a crucial determinant for the slow activation kinetics of CaV 1.1 currents and implicate STAC proteins as modulators of both components of inactivation of LTCC.
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Affiliation(s)
- Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Irene Mahlknecht
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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13
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White R, Schiemann AH, Burling SM, Bjorksten A, Bulger T, Gillies R, Hopkins PM, Kamsteeg EJ, Machon RG, Massey S, Miller D, Perry M, Snoeck MM, Stephens J, Street N, van den Bersselaar LR, Stowell KM. Functional analysis of RYR1 variants in patients with confirmed susceptibility to malignant hyperthermia. Br J Anaesth 2022; 129:879-888. [DOI: 10.1016/j.bja.2022.08.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 11/02/2022] Open
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14
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Rossi D, Catallo MR, Pierantozzi E, Sorrentino V. Mutations in proteins involved in E-C coupling and SOCE and congenital myopathies. J Gen Physiol 2022; 154:213407. [PMID: 35980353 PMCID: PMC9391951 DOI: 10.1085/jgp.202213115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/15/2022] [Accepted: 07/21/2022] [Indexed: 11/24/2022] Open
Abstract
In skeletal muscle, Ca2+ necessary for muscle contraction is stored and released from the sarcoplasmic reticulum (SR), a specialized form of endoplasmic reticulum through the mechanism known as excitation–contraction (E-C) coupling. Following activation of skeletal muscle contraction by the E-C coupling mechanism, replenishment of intracellular stores requires reuptake of cytosolic Ca2+ into the SR by the activity of SR Ca2+-ATPases, but also Ca2+ entry from the extracellular space, through a mechanism called store-operated calcium entry (SOCE). The fine orchestration of these processes requires several proteins, including Ca2+ channels, Ca2+ sensors, and Ca2+ buffers, as well as the active involvement of mitochondria. Mutations in genes coding for proteins participating in E-C coupling and SOCE are causative of several myopathies characterized by a wide spectrum of clinical phenotypes, a variety of histological features, and alterations in intracellular Ca2+ balance. This review summarizes current knowledge on these myopathies and discusses available knowledge on the pathogenic mechanisms of disease.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.,Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Maria Rosaria Catallo
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.,Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
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15
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El Ghaleb Y, Ortner NJ, Posch W, Fernández-Quintero ML, Tuinte WE, Monteleone S, Draheim HJ, Liedl KR, Wilflingseder D, Striessnig J, Tuluc P, Flucher BE, Campiglio M. Calcium current modulation by the γ1 subunit depends on alternative splicing of CaV1.1. J Gen Physiol 2022; 154:e202113028. [PMID: 35349630 PMCID: PMC9037348 DOI: 10.1085/jgp.202113028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 03/08/2022] [Indexed: 01/01/2023] Open
Abstract
The skeletal muscle voltage-gated calcium channel (CaV1.1) primarily functions as a voltage sensor for excitation-contraction coupling. Conversely, its ion-conducting function is modulated by multiple mechanisms within the pore-forming α1S subunit and the auxiliary α2δ-1 and γ1 subunits. In particular, developmentally regulated alternative splicing of exon 29, which inserts 19 amino acids in the extracellular IVS3-S4 loop of CaV1.1a, greatly reduces the current density and shifts the voltage dependence of activation to positive potentials outside the physiological range. We generated new HEK293 cell lines stably expressing α2δ-1, β3, and STAC3. When the adult (CaV1.1a) and embryonic (CaV1.1e) splice variants were expressed in these cells, the difference in the voltage dependence of activation observed in muscle cells was reproduced, but not the reduced current density of CaV1.1a. Only when we further coexpressed the γ1 subunit was the current density of CaV1.1a, but not that of CaV1.1e, reduced by >50%. In addition, γ1 caused a shift of the voltage dependence of inactivation to negative voltages in both variants. Thus, the current-reducing effect of γ1, unlike its effect on inactivation, is specifically dependent on the inclusion of exon 29 in CaV1.1a. Molecular structure modeling revealed several direct ionic interactions between residues in the IVS3-S4 loop and the γ1 subunit. However, substitution of these residues by alanine, individually or in combination, did not abolish the γ1-dependent reduction of current density, suggesting that structural rearrangements in CaV1.1a induced by inclusion of exon 29 may allosterically empower the γ1 subunit to exert its inhibitory action on CaV1.1 calcium currents.
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Affiliation(s)
- Yousra El Ghaleb
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Nadine J. Ortner
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Wilfried Posch
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Wietske E. Tuinte
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Stefania Monteleone
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Henning J. Draheim
- Boehringer Ingelheim Pharma GmbH & Co KG, CNS Research, Biberach an der Riss, Germany
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Doris Wilflingseder
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E. Flucher
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
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16
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Zhang J, Wen H, Qi X, Zhang Y, Dong X, Zhang K, Zhang M, Li J, Li Y. Morphological and Molecular Responses of Lateolabrax maculatus Skeletal Muscle Cells to Different Temperatures. Int J Mol Sci 2022; 23:ijms23179812. [PMID: 36077203 PMCID: PMC9456278 DOI: 10.3390/ijms23179812] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 11/25/2022] Open
Abstract
Temperature strongly modulates muscle development and growth in ectothermic teleosts; however, the underlying mechanisms remain largely unknown. In this study, primary cultures of skeletal muscle cells of Lateolabrax maculatus were conducted and reared at different temperatures (21, 25, and 28 °C) in both the proliferation and differentiation stages. CCK-8, EdU, wound scratch and nuclear fusion index assays revealed that the proliferation, myogenic differentiation, and migration processes of skeletal muscle cells were significantly accelerated as the temperature raises. Based on the GO, GSEA, and WGCNA, higher temperature (28 °C) induced genes involved in HSF1 activation, DNA replication, and ECM organization processes at the proliferation stage, as well as HSF1 activation, calcium activity regulation, myogenic differentiation, and myoblast fusion, and sarcomere assembly processes at the differentiation stage. In contrast, lower temperature (21 °C) increased the expression levels of genes associated with DNA damage, DNA repair and apoptosis processes at the proliferation stage, and cytokine signaling and neutrophil degranulation processes at the differentiation stage. Additionally, we screened several hub genes regulating myogenesis processes. Our results could facilitate the understanding of the regulatory mechanism of temperature on fish skeletal muscle growth and further contribute to utilizing rational management strategies and promoting organism growth and development.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Yun Li
- Correspondence: ; Tel.: +86-0532-82-031-792
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17
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Gromand M, Gueguen P, Pervillé A, Ferroul F, Morel G, Harouna A, Doray B, Urtizberea JA, Alessandri JL, Robin S. STAC3 related congenital myopathy: A case series of seven Comorian patients. Eur J Med Genet 2022; 65:104598. [PMID: 36030003 DOI: 10.1016/j.ejmg.2022.104598] [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: 02/21/2022] [Revised: 05/29/2022] [Accepted: 08/21/2022] [Indexed: 11/17/2022]
Abstract
The Bailey-Bloch congenital myopathy, also known as Native American myopathy (NAM), is an autosomal recessive congenital myopathy first reported in the Lumbee tribe people settled in North Carolina (USA), and characterized by congenital weakness and arthrogryposis, cleft palate, ptosis, short stature, kyphoscoliosis, talipes deformities, and susceptibility to malignant hyperthermia (MH) triggered by anesthesia. NAM is linked to STAC3 gene coding for a component of excitation-contraction coupling in skeletal muscles. A homozygous missense variant (c.851G > C; p.Trp284Ser) in STAC3 segregated with NAM in the Lumbee families. Non-Native American patients with STAC3 related congenital myopathy, and with other various variants of STAC3 have been reported. Here, we present seven patients from the Comoros Islands (located in the Mozambique Channel) diagnosed with STAC3 related congenital myopathy and having the recurrent variant identified in the Lumbee people. The series is the second largest series of patients having STAC3 related congenital myopathy with a shared ethnicity after le Lumbee series. Local history and geography may explain the overrepresentation of NAM in the Comorian Archipelago with a founder effect. Further researches would be necessary for the understanding of the onset of the NAM in Comorian population as search of the "classical" STAC3 variant in East African population, and haplotypes comparison between Comorian and Lumbee patients.
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Affiliation(s)
- Marie Gromand
- Department of Pediatrics, University Hospital Félix Guyon, La Réunion, France
| | - Paul Gueguen
- Department of Medical Genetics, University Hospital Félix Guyon, La Réunion, France
| | | | - Fanny Ferroul
- Department of Medical Genetics, University Hospital Félix Guyon, La Réunion, France
| | - Godelieve Morel
- Department of Medical Genetics, University Hospital Félix Guyon, La Réunion, France
| | | | - Bérénice Doray
- Department of Medical Genetics, University Hospital Félix Guyon, La Réunion, France
| | - J Andoni Urtizberea
- Centre de Compétence Neuromusculaire, FILNEMUS, Hôpital Marin, Hendaye, France
| | - Jean-Luc Alessandri
- Department of Medical Genetics, University Hospital Félix Guyon, La Réunion, France.
| | - Stéphanie Robin
- Department of Pediatrics, University Hospital Félix Guyon, La Réunion, France
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18
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Ashida Y, Himori K, Tokuda N, Naito A, Yamauchi N, Takenaka-Ninagawa N, Aoki Y, Sakurai H, Yamada T. Dissociation of SH3 and cysteine rich domain 3 and junctophilin 1 from dihydropyridine receptor in dystrophin-deficient muscles. Am J Physiol Cell Physiol 2022; 323:C885-C895. [PMID: 35912995 DOI: 10.1152/ajpcell.00163.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The disruption of excitation-contraction (EC) coupling and subsequent reduction in Ca2+ release from the sarcoplasmic reticulum (SR) have been shown to account for muscle weakness seen in patients with Duchenne muscular dystrophy (DMD). Here, we examined the mechanisms underlying EC uncoupling in skeletal muscles from mdx52 and DMD-null/NSG mice, animal models for DMD, focusing on the SH3 and cysteine rich domain 3 (STAC3) and junctophilin 1 (JP1), which link the dihydropyridine receptor (DHPR) in the transverse tubule and the ryanodine receptor 1 in the SR. The isometric plantarflexion torque normalized to muscle weight of whole plantar flexor muscles was depressed in mdx52 and DMD-null/NSG mice compared to their control mice. This was accompanied by increased autolysis of calpain-1, decreased levels of STAC3 and JP1 content, and dissociation of STAC3 and JP1 from DHPR-α1s in gastrocnemius muscles. Moreover, in vitro mechanistic experiments demonstrated that STAC3 and JP1 underwent Ca2+-dependent proteolysis which was less pronounced in dystrophin-deficient muscles where calpastatin, the endogenous calpain inhibitor, was upregulated. Eccentric contractions further enhanced autolysis of calpain-1 and proteolysis of STAC3 and JP1 that were associated with severe torque depression in gastrocnemius muscles from DMD-null/NSG mice. These data suggest that Ca2+-dependent proteolysis of STAC3 and JP1 may be an essential factor causing muscle weakness due to EC coupling failure in dystrophin-deficient muscles.
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Affiliation(s)
- Yuki Ashida
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan.,Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Koichi Himori
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan.,Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Nao Tokuda
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Azuma Naito
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Nao Yamauchi
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | | | - Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Hidetoshi Sakurai
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Takashi Yamada
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
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19
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Shishmarev D, Rowland E, Aditya S, Sundararaj S, Oakley AJ, Dulhunty AF, Casarotto MG. Molecular interactions of
STAC
proteins with skeletal muscle dihydropyridine receptor and excitation‐contraction coupling. Protein Sci 2022; 31:e4311. [PMID: 35481653 PMCID: PMC9019556 DOI: 10.1002/pro.4311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/20/2022] [Accepted: 04/01/2022] [Indexed: 01/06/2023]
Abstract
Excitation‐contraction coupling (ECC) is the physiological process in which an electrical signal originating from the central nervous system is converted into muscle contraction. In skeletal muscle tissue, the key step in the molecular mechanism of ECC initiated by the muscle action potential is the cooperation between two Ca2+ channels, dihydropyridine receptor (DHPR; voltage‐dependent L‐type calcium channel) and ryanodine receptor 1 (RyR1). These two channels were originally postulated to communicate with each other via direct mechanical interactions; however, the molecular details of this cooperation have remained ambiguous. Recently, it has been proposed that one or more supporting proteins are in fact required for communication of DHPR with RyR1 during the ECC process. One such protein that is increasingly believed to play a role in this interaction is the SH3 and cysteine‐rich domain‐containing protein 3 (STAC3), which has been proposed to bind a cytosolic portion of the DHPR α1S subunit known as the II–III loop. In this work, we present direct evidence for an interaction between a small peptide sequence of the II–III loop and several residues within the SH3 domains of STAC3 as well as the neuronal isoform STAC2. Differences in this interaction between STAC3 and STAC2 suggest that STAC3 possesses distinct biophysical features that are potentially important for its physiological interactions with the II–III loop. Therefore, this work demonstrates an isoform‐specific interaction between STAC3 and the II–III loop of DHPR and provides novel insights into a putative molecular mechanism behind this association in the skeletal muscle ECC process.
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Affiliation(s)
- Dmitry Shishmarev
- John Curtin School of Medical Research Australian National University Canberra Australia
- Research School of Biology Australian National University Canberra Australia
| | - Emily Rowland
- John Curtin School of Medical Research Australian National University Canberra Australia
- Division of Structural Biology, Wellcome Centre for Human Genetics University of Oxford Oxford UK
| | - Shouvik Aditya
- John Curtin School of Medical Research Australian National University Canberra Australia
- Research School of Biology Australian National University Canberra Australia
| | - Srinivasan Sundararaj
- John Curtin School of Medical Research Australian National University Canberra Australia
| | - Aaron J. Oakley
- School of Chemistry & Molecular Bioscience and Molecular Horizons University of Wollongong Wollongong Australia
| | - Angela F. Dulhunty
- John Curtin School of Medical Research Australian National University Canberra Australia
| | - Marco G. Casarotto
- Research School of Biology Australian National University Canberra Australia
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20
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Rossi D, Pierantozzi E, Amadsun DO, Buonocore S, Rubino EM, Sorrentino V. The Sarcoplasmic Reticulum of Skeletal Muscle Cells: A Labyrinth of Membrane Contact Sites. Biomolecules 2022; 12:488. [PMID: 35454077 PMCID: PMC9026860 DOI: 10.3390/biom12040488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/14/2022] [Accepted: 03/18/2022] [Indexed: 12/17/2022] Open
Abstract
The sarcoplasmic reticulum of skeletal muscle cells is a highly ordered structure consisting of an intricate network of tubules and cisternae specialized for regulating Ca2+ homeostasis in the context of muscle contraction. The sarcoplasmic reticulum contains several proteins, some of which support Ca2+ storage and release, while others regulate the formation and maintenance of this highly convoluted organelle and mediate the interaction with other components of the muscle fiber. In this review, some of the main issues concerning the biology of the sarcoplasmic reticulum will be described and discussed; particular attention will be addressed to the structure and function of the two domains of the sarcoplasmic reticulum supporting the excitation-contraction coupling and Ca2+-uptake mechanisms.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy; (E.P.); (D.O.A.); (S.B.); (E.M.R.); (V.S.)
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21
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Yang ZF, Panwar P, McFarlane CR, Tuinte WE, Campiglio M, Van Petegem F. Structures of the junctophilin/voltage-gated calcium channel interface reveal hot spot for cardiomyopathy mutations. Proc Natl Acad Sci U S A 2022; 119:e2120416119. [PMID: 35238659 PMCID: PMC8916002 DOI: 10.1073/pnas.2120416119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/31/2022] [Indexed: 01/19/2023] Open
Abstract
SignificanceIon channels have evolved the ability to communicate with one another, either through protein-protein interactions, or indirectly via intermediate diffusible messenger molecules. In special cases, the channels are part of different membranes. In muscle tissue, the T-tubule membrane is in proximity to the sarcoplasmic reticulum, allowing communication between L-type calcium channels and ryanodine receptors. This process is critical for excitation-contraction coupling and requires auxiliary proteins like junctophilin (JPH). JPHs are targets for disease-associated mutations, most notably hypertrophic cardiomyopathy mutations in the JPH2 isoform. Here we provide high-resolution snapshots of JPH, both alone and in complex with a calcium channel peptide, and show how this interaction is targeted by cardiomyopathy mutations.
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Affiliation(s)
- Zheng Fang Yang
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Pankaj Panwar
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ciaran R. McFarlane
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Wietske E. Tuinte
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, 6020 Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, 6020 Austria
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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22
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Perni S. The Builders of the Junction: Roles of Junctophilin1 and Junctophilin2 in the Assembly of the Sarcoplasmic Reticulum–Plasma Membrane Junctions in Striated Muscle. Biomolecules 2022; 12:biom12010109. [PMID: 35053257 PMCID: PMC8774113 DOI: 10.3390/biom12010109] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 02/06/2023] Open
Abstract
Contraction of striated muscle is triggered by a massive release of calcium from the sarcoplasmic reticulum (SR) into the cytoplasm. This intracellular calcium release is initiated by membrane depolarization, which is sensed by voltage-gated calcium channels CaV1.1 (in skeletal muscle) and CaV1.2 (in cardiac muscle) in the plasma membrane (PM), which in turn activate the calcium-releasing channel ryanodine receptor (RyR) embedded in the SR membrane. This cross-communication between channels in the PM and in the SR happens at specialized regions, the SR-PM junctions, where these two compartments come in close proximity. Junctophilin1 and Junctophilin2 are responsible for the formation and stabilization of SR-PM junctions in striated muscle and actively participate in the recruitment of the two essential players in intracellular calcium release, CaV and RyR. This short review focuses on the roles of junctophilins1 and 2 in the formation and organization of SR-PM junctions in skeletal and cardiac muscle and on the functional consequences of the absence or malfunction of these proteins in striated muscle in light of recently published data and recent advancements in protein structure prediction.
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Affiliation(s)
- Stefano Perni
- Department of Physiology and Biophysics, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA
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23
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Jaque-Fernández F, Jorquera G, Troc-Gajardo J, Pietri-Rouxel F, Gentil C, Buvinic S, Allard B, Jaimovich E, Jacquemond V, Casas M. Pannexin-1 and CaV1.1 show reciprocal interaction during excitation-contraction and excitation-transcription coupling in skeletal muscle. J Gen Physiol 2021; 153:212695. [PMID: 34636893 PMCID: PMC8515650 DOI: 10.1085/jgp.202012635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/24/2021] [Accepted: 09/15/2021] [Indexed: 01/18/2023] Open
Abstract
One of the most important functions of skeletal muscle is to respond to nerve stimuli by contracting. This function ensures body movement but also participates in other important physiological roles, like regulation of glucose homeostasis. Muscle activity is closely regulated to adapt to different demands and shows a plasticity that relies on both transcriptional activity and nerve stimuli. These two processes, both dependent on depolarization of the plasma membrane, have so far been regarded as separated and independent processes due to a lack of evidence of common protein partners or molecular mechanisms. In this study, we reveal intimate functional interactions between the process of excitation-induced contraction and the process of excitation-induced transcriptional activity in skeletal muscle. We show that the plasma membrane voltage-sensing protein CaV1.1 and the ATP-releasing channel Pannexin-1 (Panx1) regulate each other in a reciprocal manner, playing roles in both processes. Specifically, knockdown of CaV1.1 produces chronically elevated extracellular ATP concentrations at rest, consistent with disruption of the normal control of Panx1 activity. Conversely, knockdown of Panx1 affects not only activation of transcription but also CaV1.1 function on the control of muscle fiber contraction. Altogether, our results establish the presence of bidirectional functional regulations between the molecular machineries involved in the control of contraction and transcription induced by membrane depolarization of adult muscle fibers. Our results are important for an integrative understanding of skeletal muscle function and may impact our understanding of several neuromuscular diseases.
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Affiliation(s)
- Francisco Jaque-Fernández
- Programa de Fisiología y Biofísica, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Gonzalo Jorquera
- Programa de Fisiología y Biofísica, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,Centro de Neurobiología y Fisiopatología Integrativa, Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Jennifer Troc-Gajardo
- Programa de Fisiología y Biofísica, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - France Pietri-Rouxel
- Université Pierre et Marie Curie, Université Paris 06, Institut National de la Santé et de la Recherche Médicale/Centre National de la Recherche Scientifique/Institut de Myologie/Centre de Recherche en Myologie, Groupement hospitalier universitaire Pitié Salpêtrière, Paris, France
| | - Christel Gentil
- Université Pierre et Marie Curie, Université Paris 06, Institut National de la Santé et de la Recherche Médicale/Centre National de la Recherche Scientifique/Institut de Myologie/Centre de Recherche en Myologie, Groupement hospitalier universitaire Pitié Salpêtrière, Paris, France
| | - Sonja Buvinic
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Bruno Allard
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Enrique Jaimovich
- Programa de Fisiología y Biofísica, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,Center for Exercise, Metabolism and Cancer, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Vincent Jacquemond
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Mariana Casas
- Programa de Fisiología y Biofísica, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.,Center for Exercise, Metabolism and Cancer, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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24
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Ashida Y, Himori K, Tamai K, Kimura I, Yamada T. Preconditioning contractions prevent prolonged force depression and Ca 2+-dependent proteolysis of STAC3 after damaging eccentric contractions. J Appl Physiol (1985) 2021; 131:1399-1407. [PMID: 34590910 DOI: 10.1152/japplphysiol.00463.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Preconditioning contractions (PCs) have been shown to markedly improve recovery from eccentric contractions (ECCs)-induced force depression. We here examined the mechanism behind the effects of PCs with focusing on the SH3 and cysteine-rich domain 3 (STAC3) that is essential for coupling membrane depolarization to Ca2+ release from the sarcoplasmic reticulum. Rat medial gastrocnemius (MG) muscles were excised immediately (REC0), 1 day (REC1), and 4 days (REC4) after exposure to 100 repeated damaging ECCs in vivo. PCs with 10 repeated nondamaging ECCs were applied 2 days before the damaging ECCs. Damaging ECCs induced in vivo isometric torque depression at 50 and 100 Hz stimulation frequencies, which was accompanied by a significant decrease in the amount of full-length STAC3, an activation of calpain 1, and an increased number of Evans Blue dye-positive fibers in MG muscles at REC1 and REC4. Interestingly, PCs attenuated all these deleterious alterations induced by damaging ECCs. Moreover, mechanistic experiments performed on normal muscle samples exposed to various concentration of Ca2+ showed a Ca2+-dependent proteolysis of STAC3, which was prevented by calpain inhibitor MDL-28170. In conclusion, PCs may improve recovery from force depression after damaging ECCs, in part by inhibiting the loss of STAC3 due to the increased permeability of cell membrane and subsequent activation of calpain 1.NEW & NOTEWORTHY The SH3 and cysteine-rich domain 3 (STAC3) is a skeletal muscle-specific protein that couples membrane depolarization to sarcoplasmic reticulum Ca2+ release. No studies, however, examined the role of STAC3 in protective effects of preconditioning contractions (PCs) against damaging eccentric contractions (ECCs). Here, we demonstrate that PCs may improve recovery from damaging ECCs-induced force depression, in part by an inhibition of Ca2+-dependent proteolysis of STAC3 due to increased membrane permeability and subsequent calpain 1 activation.
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Affiliation(s)
- Yuki Ashida
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan.,The Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Koichi Himori
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan.,The Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Katsuyuki Tamai
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Iori Kimura
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Takashi Yamada
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
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25
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Molecular and cellular basis of genetically inherited skeletal muscle disorders. Nat Rev Mol Cell Biol 2021; 22:713-732. [PMID: 34257452 PMCID: PMC9686310 DOI: 10.1038/s41580-021-00389-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2021] [Indexed: 02/06/2023]
Abstract
Neuromuscular disorders comprise a diverse group of human inborn diseases that arise from defects in the structure and/or function of the muscle tissue - encompassing the muscle cells (myofibres) themselves and their extracellular matrix - or muscle fibre innervation. Since the identification in 1987 of the first genetic lesion associated with a neuromuscular disorder - mutations in dystrophin as an underlying cause of Duchenne muscular dystrophy - the field has made tremendous progress in understanding the genetic basis of these diseases, with pathogenic variants in more than 500 genes now identified as underlying causes of neuromuscular disorders. The subset of neuromuscular disorders that affect skeletal muscle are referred to as myopathies or muscular dystrophies, and are due to variants in genes encoding muscle proteins. Many of these proteins provide structural stability to the myofibres or function in regulating sarcolemmal integrity, whereas others are involved in protein turnover, intracellular trafficking, calcium handling and electrical excitability - processes that ensure myofibre resistance to stress and their primary activity in muscle contraction. In this Review, we discuss how defects in muscle proteins give rise to muscle dysfunction, and ultimately to disease, with a focus on pathologies that are most common, best understood and that provide the most insight into muscle biology.
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26
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Tuluc P, Theiner T, Jacobo-Piqueras N, Geisler SM. Role of High Voltage-Gated Ca 2+ Channel Subunits in Pancreatic β-Cell Insulin Release. From Structure to Function. Cells 2021; 10:2004. [PMID: 34440773 PMCID: PMC8393260 DOI: 10.3390/cells10082004] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/27/2021] [Accepted: 08/03/2021] [Indexed: 02/07/2023] Open
Abstract
The pancreatic islets of Langerhans secrete several hormones critical for glucose homeostasis. The β-cells, the major cellular component of the pancreatic islets, secrete insulin, the only hormone capable of lowering the plasma glucose concentration. The counter-regulatory hormone glucagon is secreted by the α-cells while δ-cells secrete somatostatin that via paracrine mechanisms regulates the α- and β-cell activity. These three peptide hormones are packed into secretory granules that are released through exocytosis following a local increase in intracellular Ca2+ concentration. The high voltage-gated Ca2+ channels (HVCCs) occupy a central role in pancreatic hormone release both as a source of Ca2+ required for excitation-secretion coupling as well as a scaffold for the release machinery. HVCCs are multi-protein complexes composed of the main pore-forming transmembrane α1 and the auxiliary intracellular β, extracellular α2δ, and transmembrane γ subunits. Here, we review the current understanding regarding the role of all HVCC subunits expressed in pancreatic β-cell on electrical activity, excitation-secretion coupling, and β-cell mass. The evidence we review was obtained from many seminal studies employing pharmacological approaches as well as genetically modified mouse models. The significance for diabetes in humans is discussed in the context of genetic variations in the genes encoding for the HVCC subunits.
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Affiliation(s)
- Petronel Tuluc
- Centre for Molecular Biosciences, Department of Pharmacology and Toxicology, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria; (T.T.); (N.J.-P.); (S.M.G.)
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27
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Woll KA, Van Petegem F. Calcium Release Channels: Structure and Function of IP3 Receptors and Ryanodine Receptors. Physiol Rev 2021; 102:209-268. [PMID: 34280054 DOI: 10.1152/physrev.00033.2020] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca2+-release channels are giant membrane proteins that control the release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. The two members, ryanodine receptors (RyRs) and inositol-1,4,5-trisphosphate Receptors (IP3Rs), are evolutionarily related and are both activated by cytosolic Ca2+. They share a common architecture, but RyRs have evolved additional modules in the cytosolic region. Their massive size allows for the regulation by tens of proteins and small molecules, which can affect the opening and closing of the channels. In addition to Ca2+, other major triggers include IP3 for the IP3Rs, and depolarization of the plasma membrane for a particular RyR subtype. Their size has made them popular targets for study via electron microscopic methods, with current structures culminating near 3Å. The available structures have provided many new mechanistic insights int the binding of auxiliary proteins and small molecules, how these can regulate channel opening, and the mechanisms of disease-associated mutations. They also help scrutinize previously proposed binding sites, as some of these are now incompatible with the structures. Many questions remain around the structural effects of post-translational modifications, additional binding partners, and the higher-order complexes these channels can make in situ. This review summarizes our current knowledge about the structures of Ca2+-release channels and how this informs on their function.
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Affiliation(s)
- Kellie A Woll
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
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28
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Miranda DR, Voss AA, Bannister RA. Into the spotlight: RGK proteins in skeletal muscle. Cell Calcium 2021; 98:102439. [PMID: 34261001 DOI: 10.1016/j.ceca.2021.102439] [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: 06/03/2021] [Revised: 06/24/2021] [Accepted: 06/26/2021] [Indexed: 10/20/2022]
Abstract
The RGK (Rad, Rem, Rem2 and Gem/Kir) family of small GTPases are potent endogenous inhibitors of voltage-gated Ca2+ channels (VGCCs). While the impact of RGK proteins on cardiac physiology has been investigated extensively, much less is known regarding their influence on skeletal muscle biology. Thus, the purpose of this article is to establish a basis for future investigation into the role of RGK proteins in regulating the skeletal muscle excitation-contraction (EC) coupling complex via modulation of the L-type CaV1.1 VGCC. The pathological consequences of elevated muscle RGK protein expression in Type II Diabetes, Amyotrophic Lateral Sclerosis (ALS), Duchenne's Muscular Dystrophy and traumatic nerve injury are also discussed.
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Affiliation(s)
- Daniel R Miranda
- Department of Biological Sciences, College of Science and Mathematics, Wright State University, 235A Biological Sciences, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
| | - Andrew A Voss
- Department of Biological Sciences, College of Science and Mathematics, Wright State University, 235A Biological Sciences, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA.
| | - Roger A Bannister
- Departments of Pathology and Biochemistry & Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA.
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29
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Rufenach B, Van Petegem F. Structure and function of STAC proteins: Calcium channel modulators and critical components of muscle excitation-contraction coupling. J Biol Chem 2021; 297:100874. [PMID: 34129875 PMCID: PMC8258685 DOI: 10.1016/j.jbc.2021.100874] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 06/02/2021] [Accepted: 06/11/2021] [Indexed: 12/26/2022] Open
Abstract
In skeletal muscle tissue, an intriguing mechanical coupling exists between two ion channels from different membranes: the L-type voltage-gated calcium channel (CaV1.1), located in the plasma membrane, and ryanodine receptor 1 (RyR1) located in the sarcoplasmic reticulum membrane. Excitable cells rely on Cavs to initiate Ca2+ entry in response to action potentials. RyRs can amplify this signal by releasing Ca2+ from internal stores. Although this process can be mediated through Ca2+ as a messenger, an overwhelming amount of evidence suggests that RyR1 has recruited CaV1.1 directly as its voltage sensor. The exact mechanisms that underlie this coupling have been enigmatic, but a recent wave of reports have illuminated the coupling protein STAC3 as a critical player. Without STAC3, the mechanical coupling between Cav1.1 and RyR1 is lost, and muscles fail to contract. Various sequence variants of this protein have been linked to congenital myopathy. Other STAC isoforms are expressed in the brain and may serve as regulators of L-type CaVs. Despite the short length of STACs, several points of contacts have been proposed between them and CaVs. However, it is currently unclear whether STAC3 also forms direct interactions with RyR1, and whether this modulates RyR1 function. In this review, we discuss the 3D architecture of STAC proteins, the biochemical evidence for their interactions, the relevance of these connections for functional modulation, and their involvement in myopathy.
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Affiliation(s)
- Britany Rufenach
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
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30
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Watanabe D, Wada M. Orthograde signal of dihydropyridine receptor increases Ca 2+ leakage after repeated contractions in rat fast-twitch muscles in vivo. Am J Physiol Cell Physiol 2021; 320:C806-C821. [PMID: 33596151 DOI: 10.1152/ajpcell.00364.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 02/10/2021] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to investigate the mechanism underlying sarcoplasmic reticulum (SR) Ca2+ leakage after in vivo contractions. Rat gastrocnemius muscles were electrically stimulated in vivo, and then mechanically skinned fibers and SR microsomes were prepared from the muscles excised 30 min after repeated high-intensity contractions. The mechanically skinned fibers maintained the interaction between dihydropyridine receptors (DHPRs) and ryanodine receptors (RyRs), whereas the SR microsomes did not. Interestingly, skinned fibers from the stimulated muscles showed increased SR Ca2+ leakage, whereas Ca2+ leakage decreased in SR microsomes from the stimulated muscles. To enhance the orthograde signal of DHPRs, SR Ca2+ leakage in the skinned fiber was measured 1) under a continuously depolarized condition and 2) in the presence of nifedipine. As a result, in either of the two conditions, SR Ca2+ leakage in the rested fibers reached a level similar to that in the stimulated fibers. Furthermore, the increased SR Ca2+ leakage from the stimulated fibers was alleviated by treatment with 1 mM tetracaine (Tet) but not by treatment with 3 mM free Mg2+ (3 Mg). Tet exerted a greater inhibitory effect on the DHPR signal to RyR than 3 Mg, although their inhibitory effects on RyR were almost similar. These results suggest that the increased Ca2+ leakage after muscle contractions is mainly caused by the orthograde signal of DHPRs to RyRs.
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Affiliation(s)
- Daiki Watanabe
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
| | - Masanobu Wada
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
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31
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Hsu IU, Linsley JW, Reid LE, Hume RI, Leflein A, Kuwada JY. Dstac Regulates Excitation-Contraction Coupling in Drosophila Body Wall Muscles. Front Physiol 2020; 11:573723. [PMID: 33123029 PMCID: PMC7573238 DOI: 10.3389/fphys.2020.573723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/15/2020] [Indexed: 12/13/2022] Open
Abstract
Stac3 regulates excitation-contraction coupling (EC coupling) in vertebrate skeletal muscles by regulating the L-type voltage-gated calcium channel (Cav channel). Recently a stac-like gene, Dstac, was identified in Drosophila and found to be expressed by both a subset of neurons and muscles. Here, we show that Dstac and Dmca1D, the Drosophila L-type Cav channel, are necessary for normal locomotion by larvae. Immunolabeling with specific antibodies against Dstac and Dmca1D found that Dstac and Dmca1D are expressed by larval body-wall muscles. Furthermore, Ca2+ imaging of muscles of Dstac and Dmca1D deficient larvae found that Dstac and Dmca1D are required for excitation-contraction coupling. Finally, Dstac appears to be required for normal expression levels of Dmca1D in body-wall muscles. These results suggest that Dstac regulates Dmca1D during EC coupling and thus muscle contraction.
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Affiliation(s)
- I-Uen Hsu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Jeremy W Linsley
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, United States
| | - Lilly E Reid
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Richard I Hume
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Ari Leflein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - John Y Kuwada
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, United States
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32
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Rufenach B, Christy D, Flucher BE, Bui JM, Gsponer J, Campiglio M, Van Petegem F. Multiple Sequence Variants in STAC3 Affect Interactions with CaV1.1 and Excitation-Contraction Coupling. Structure 2020; 28:922-932.e5. [DOI: 10.1016/j.str.2020.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/03/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
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33
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Schartner V, Laporte J, Böhm J. Abnormal Excitation-Contraction Coupling and Calcium Homeostasis in Myopathies and Cardiomyopathies. J Neuromuscul Dis 2020; 6:289-305. [PMID: 31356215 DOI: 10.3233/jnd-180314] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Muscle contraction requires specialized membrane structures with precise geometry and relies on the concerted interplay of electrical stimulation and Ca2+ release, known as excitation-contraction coupling (ECC). The membrane structure hosting ECC is called triad in skeletal muscle and dyad in cardiac muscle, and structural or functional defects of triads and dyads have been observed in a variety of myopathies and cardiomyopathies. Based on their function, the proteins localized at the triad/dyad can be classified into three molecular pathways: the Ca2+ release complex (CRC), store-operated Ca2+ entry (SOCE), and membrane remodeling. All three are mechanistically linked, and consequently, aberrations in any of these pathways cause similar disease entities. This review provides an overview of the clinical and genetic spectrum of triad and dyad defects with a main focus of attention on the underlying pathomechanisms.
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Affiliation(s)
- Vanessa Schartner
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
| | - Johann Böhm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
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34
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Shishmarev D. Excitation-contraction coupling in skeletal muscle: recent progress and unanswered questions. Biophys Rev 2020; 12:143-153. [PMID: 31950344 DOI: 10.1007/s12551-020-00610-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 01/03/2020] [Indexed: 02/07/2023] Open
Abstract
Excitation-contraction coupling (ECC) is a physiological process that links excitation of muscles by the nervous system to their mechanical contraction. In skeletal muscle, ECC is initiated with an action potential, generated by the somatic nervous system, which causes a depolarisation of the muscle fibre membrane (sarcolemma). This leads to a rapid change in the transmembrane potential, which is detected by the voltage-gated Ca2+ channel dihydropyridine receptor (DHPR) embedded in the sarcolemma. DHPR transmits the contractile signal to another Ca2+ channel, ryanodine receptor (RyR1), embedded in the membrane of the sarcoplasmic reticulum (SR), which releases a large amount of Ca2+ ions from the SR that initiate muscle contraction. Despite the fundamental role of ECC in skeletal muscle function of all vertebrate species, the molecular mechanism underpinning the communication between the two key proteins involved in the process (DHPR and RyR1) is still largely unknown. The goal of this work is to review the recent progress in our understanding of ECC in skeletal muscle from the point of view of the structure and interactions of proteins involved in the process, and to highlight the unanswered questions in the field.
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Affiliation(s)
- Dmitry Shishmarev
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
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35
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Schiemann AH, Roesl C, Pollock N, Langton E, Bulger T, Stowell KM. Identification and Functional Analysis of RYR1 Variants in a Family with a Suspected Myopathy and Associated Malignant Hyperthermia. J Neuromuscul Dis 2020; 7:51-60. [PMID: 31903994 DOI: 10.3233/jnd-190430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The ryanodine receptor 1 (RyR1) is a major skeletal muscle calcium release channel located in the sarcoplasmic reticulum and involved in excitation-contraction coupling. Variants in the gene encoding RyR1 have been linked to a range of neuromuscular disorders including myopathies and malignant hyperthermia (MH). OBJECTIVE We have identified three RYR1 variants (c.1983 G>A, p.Trp661*; c.7025A>G, p.Asn2342Ser and c.2447 C>T, p.Pro816Leu) in a family with a suspected myopathy and associated malignant hyperthermia susceptibility. We used calcium release assays to functionally characterise these variants in a recombinant system. METHODS Site-directed mutagenesis was used to introduce each variant separately into the human RYR1 cDNA. HEK293-T cells were transfected with the recombinant constructs and calcium release assays were carried out using 4-chloro-m-cresol (4-CmC) as the RyR1 agonist to investigate the functional consequences of each variant. RESULTS RYR1 c.1983 G>A, p.Trp661* resulted in a non-functional channel, c.7025A>G, p.Asn2342Ser in a hypersensitive channel and c.2447 C>T, p.Pro816Leu in a hypersensitive channel at higher concentrations of 4-CmC. CONCLUSIONS The p.Trp661* RYR1 variant should be considered as a risk factor for myopathies. The p.Asn2342Ser RYR1 variant, when expressed as a compound heterozygote with a nonsense mutation on the second allele, is likely to result in MH-susceptibility. The role of the p.Pro816Leu variant in MH remains unclear.
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Affiliation(s)
- Anja H Schiemann
- School of Fundamental Sciences, Massey University, Manawatu, New Zealand
| | - Cornelia Roesl
- School of Fundamental Sciences, Massey University, Manawatu, New Zealand.,Present address: LifeArc, Nine, Edinburgh BioQuarter, Edinburgh, United Kingdom
| | - Neil Pollock
- Department of Anaesthesia and Intensive Care, Palmerston North Hospital, Manawatu, New Zealand.,Now retired
| | | | - Terasa Bulger
- Department of Anaesthesia and Intensive Care, Palmerston North Hospital, Manawatu, New Zealand
| | - Kathryn M Stowell
- School of Fundamental Sciences, Massey University, Manawatu, New Zealand
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36
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37
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Flucher BE, Campiglio M. STAC proteins: The missing link in skeletal muscle EC coupling and new regulators of calcium channel function. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:1101-1110. [PMID: 30543836 DOI: 10.1016/j.bbamcr.2018.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 01/19/2023]
Abstract
Excitation-contraction coupling is the signaling process by which action potentials control calcium release and consequently the force of muscle contraction. Until recently, three triad proteins were known to be essential for skeletal muscle EC coupling: the voltage-gated calcium channel CaV1.1 acting as voltage sensor, the SR calcium release channel RyR1 representing the only relevant calcium source, and the auxiliary CaV β1a subunit. Whether CaV1.1 and RyR1 are directly coupled or whether their interaction is mediated by another triad protein is still unknown. The recent identification of the adaptor protein STAC3 as fourth essential component of skeletal muscle EC coupling prompted vigorous research to reveal its role in this signaling process. Accumulating evidence supports its possible involvement in linking CaV1.1 and RyR1 in skeletal muscle EC coupling, but also indicates a second, much broader role of STAC proteins in the regulation of calcium/calmodulin-dependent feedback regulation of L-type calcium channels.
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Affiliation(s)
- Bernhard E Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, Schöpfstraße 41, A6020 Innsbruck, Austria.
| | - Marta Campiglio
- Department of Physiology and Medical Physics, Medical University Innsbruck, Schöpfstraße 41, A6020 Innsbruck, Austria
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38
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Crystal structures of Ca 2+-calmodulin bound to Na V C-terminal regions suggest role for EF-hand domain in binding and inactivation. Proc Natl Acad Sci U S A 2019; 116:10763-10772. [PMID: 31072926 DOI: 10.1073/pnas.1818618116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium (NaV) and calcium channels (CaV) form targets for calmodulin (CaM), which affects channel inactivation properties. A major interaction site for CaM resides in the C-terminal (CT) region, consisting of an IQ domain downstream of an EF-hand domain. We present a crystal structure of fully Ca2+-occupied CaM, bound to the CT of NaV1.5. The structure shows that the C-terminal lobe binds to a site ∼90° rotated relative to a previous site reported for an apoCaM complex with the NaV1.5 CT and for ternary complexes containing fibroblast growth factor homologous factors (FHF). We show that the binding of FHFs forces the EF-hand domain in a conformation that does not allow binding of the Ca2+-occupied C-lobe of CaM. These observations highlight the central role of the EF-hand domain in modulating the binding mode of CaM. The binding sites for Ca2+-free and Ca2+-occupied CaM contain targets for mutations linked to long-QT syndrome, a type of inherited arrhythmia. The related NaV1.4 channel has been shown to undergo Ca2+-dependent inactivation (CDI) akin to CaVs. We present a crystal structure of Ca2+/CaM bound to the NaV1.4 IQ domain, which shows a binding mode that would clash with the EF-hand domain. We postulate the relative reorientation of the EF-hand domain and the IQ domain as a possible conformational switch that underlies CDI.
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39
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Johnson CN. Calcium modulation of cardiac sodium channels. J Physiol 2019; 598:2835-2846. [PMID: 30707447 DOI: 10.1113/jp277553] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 01/08/2019] [Indexed: 12/28/2022] Open
Abstract
Modification of voltage-gated Na+ channel (NaV ) function by intracellular Ca2+ has been a topic of much controversy. Early studies relied on measuring NaV function in the absence or presence of intracellular Ca2+ , and generated seemingly disparate results. Subsequent investigations revealed the mechanism(s) of Ca2+ -driven NaV modulation are complex and involve multiple accessory proteins. The Ca2+ -sensing protein calmodulin (CaM) has a central role in tuning NaV function to [Ca2+ ]i , but the mechanism has been obscured by other proteins (such as fibroblast growth factors (FGF) or CaM-dependent kinase II (CaMKII)) that can also modify channel function or exert an influence in a Ca2+ -dependent manner. Significant progress has been made in understanding the architecture of full-length ion channels and the structural and biophysical details of NaV -accessory protein interactions. Interdisciplinary structure-function studies are beginning to resolve the effect each interaction has on NaV gating. Carefully designed structure-guided or strategically selected disease-associated mutations are able to impair NaV -accessory protein interactions without altering other properties of channel function. Recently CaM was found to engage part of NaV 1.5 that is required for channel inactivation with high affinity. Careful impairment of this interaction disrupted NaV 1.5's ability to recover from inactivation. Such results support a paradigm of CaM-facilitated recovery from inactivation (CFRI). How NaV -CaM, CaMKII and FGF/fibroblast growth factor homologous factor interactions affect the timing or function of CFRI in cardiomyocytes remain open questions that are discussed herein. Moreover whether CFRI dysfunction or premature activation underlie certain NaV channelopathies are important questions that will require further investigation.
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Affiliation(s)
- Christopher N Johnson
- The Ohio State Wexner Medical Centre, Dorothy M. Davis Heart & Lung Research Institute, Columbus, OH, USA.,Vanderbilt Centre for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Nashville, TN, USA
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40
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Jones PP, MacQuaide N, Louch WE. Dyadic Plasticity in Cardiomyocytes. Front Physiol 2018; 9:1773. [PMID: 30618792 PMCID: PMC6298195 DOI: 10.3389/fphys.2018.01773] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/23/2018] [Indexed: 11/13/2022] Open
Abstract
Contraction of cardiomyocytes is dependent on sub-cellular structures called dyads, where invaginations of the surface membrane (t-tubules) form functional junctions with the sarcoplasmic reticulum (SR). Within each dyad, Ca2+ entry through t-tubular L-type Ca2+ channels (LTCCs) elicits Ca2+ release from closely apposed Ryanodine Receptors (RyRs) in the SR membrane. The efficiency of this process is dependent on the density and macroscale arrangement of dyads, but also on the nanoscale organization of LTCCs and RyRs within them. We presently review accumulating data demonstrating the remarkable plasticity of these structures. Dyads are known to form gradually during development, with progressive assembly of both t-tubules and junctional SR terminals, and precise trafficking of LTCCs and RyRs. While dyads can exhibit compensatory remodeling when required, dyadic degradation is believed to promote impaired contractility and arrythmogenesis in cardiac disease. Recent data indicate that this plasticity of dyadic structure/function is dependent on the regulatory proteins junctophilin-2, amphiphysin-2 (BIN1), and caveolin-3, which critically arrange dyadic membranes while stabilizing the position and activity of LTCCs and RyRs. Indeed, emerging evidence indicates that clustering of both channels enables "coupled gating", implying that nanoscale localization and function are intimately linked, and may allow fine-tuning of LTCC-RyR crosstalk. We anticipate that improved understanding of dyadic plasticity will provide greater insight into the processes of cardiac compensation and decompensation, and new opportunities to target the basic mechanisms underlying heart disease.
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Affiliation(s)
- Peter P. Jones
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - Niall MacQuaide
- Institute of Cardiovascular Sciences, University of Glasgow, Glasgow, United Kingdom
- Clyde Biosciences, Glasgow, United Kingdom
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
- KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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41
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Pancaroglu R, Van Petegem F. Calcium Channelopathies: Structural Insights into Disorders of the Muscle Excitation–Contraction Complex. Annu Rev Genet 2018; 52:373-396. [DOI: 10.1146/annurev-genet-120417-031311] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ion channels are membrane proteins responsible for the passage of ions down their electrochemical gradients and across biological membranes. In this, they generate and shape action potentials and provide secondary messengers for various signaling pathways. They are often part of larger complexes containing auxiliary subunits and regulatory proteins. Channelopathies arise from mutations in the genes encoding ion channels or their associated proteins. Recent advances in cryo-electron microscopy have resulted in an explosion of ion channel structures in multiple states, generating a wealth of new information on channelopathies. Disease-associated mutations fall into different categories, interfering with ion permeation, protein folding, voltage sensing, ligand and protein binding, and allosteric modulation of channel gating. Prime examples of these are Ca2+-selective channels expressed in myocytes, for which multiple structures in distinct conformational states have recently been uncovered. We discuss the latest insights into these calcium channelopathies from a structural viewpoint.
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Affiliation(s)
- Raika Pancaroglu
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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42
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Zaharieva IT, Sarkozy A, Munot P, Manzur A, O'Grady G, Rendu J, Malfatti E, Amthor H, Servais L, Urtizberea JA, Neto OA, Zanoteli E, Donkervoort S, Taylor J, Dixon J, Poke G, Foley AR, Holmes C, Williams G, Holder M, Yum S, Medne L, Quijano-Roy S, Romero NB, Fauré J, Feng L, Bastaki L, Davis MR, Phadke R, Sewry CA, Bönnemann CG, Jungbluth H, Bachmann C, Treves S, Muntoni F. STAC3 variants cause a congenital myopathy with distinctive dysmorphic features and malignant hyperthermia susceptibility. Hum Mutat 2018; 39:1980-1994. [PMID: 30168660 DOI: 10.1002/humu.23635] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/27/2018] [Accepted: 08/28/2018] [Indexed: 12/14/2022]
Abstract
SH3 and cysteine-rich domain-containing protein 3 (STAC3) is an essential component of the skeletal muscle excitation-contraction coupling (ECC) machinery, though its role and function are not yet completely understood. Here, we report 18 patients carrying a homozygous p.(Trp284Ser) STAC3 variant in addition to a patient compound heterozygous for the p.(Trp284Ser) and a novel splice site change (c.997-1G > T). Clinical severity ranged from prenatal onset with severe features at birth, to a milder and slowly progressive congenital myopathy phenotype. A malignant hyperthermia (MH)-like reaction had occurred in several patients. The functional analysis demonstrated impaired ECC. In particular, KCl-induced membrane depolarization resulted in significantly reduced sarcoplasmic reticulum Ca2+ release. Co-immunoprecipitation of STAC3 with CaV 1.1 in patients and control muscle samples showed that the protein interaction between STAC3 and CaV 1.1 was not significantly affected by the STAC3 variants. This study demonstrates that STAC3 gene analysis should be included in the diagnostic work up of patients of any ethnicity presenting with congenital myopathy, in particular if a history of MH-like episodes is reported. While the precise pathomechanism remains to be elucidated, our functional characterization of STAC3 variants revealed that defective ECC is not a result of CaV 1.1 sarcolemma mislocalization or impaired STAC3-CaV 1.1 interaction.
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Affiliation(s)
- Irina T Zaharieva
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Anna Sarkozy
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, UK.,Great Ormond Street Hospital, London, UK
| | - Pinki Munot
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, UK.,Great Ormond Street Hospital, London, UK
| | - Adnan Manzur
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, UK.,Great Ormond Street Hospital, London, UK
| | - Gina O'Grady
- Institute of Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Paediatrics and Child Health Clinical School, University of Sydney, Sydney, New South Wales, Australia
| | - John Rendu
- UFR de Médecine, Centre Hospitalier Universitaire Grenoble Alpes, Université Grenoble Alpes, Grenoble, France
| | - Eduardo Malfatti
- Neuromuscular Morphology Unit and Neuromuscular Pathology Reference Center Paris-Est, Center for Research in Myology, Groupe Hospitalier Universitaire La Pitié-Salpêtrière, Paris, France
| | - Helge Amthor
- UFR des sciences de la santé, Versailles Saint-Quentin-en-Yvelines University, Montigny-le-Bretonneux, France.,Service de Pédiatrie, Centre Hospitalier Universitaire Raymond Poincaré, Garches, France
| | | | - J Andoni Urtizberea
- Centre de Compétence Neuromusculaire, FILNEMUS, Hôpital Marin, Hendaye, France
| | - Osorio Abath Neto
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil.,Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institutes of Health, Bethesda, Maryland, USA
| | - Edmar Zanoteli
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institutes of Health, Bethesda, Maryland, USA
| | - Juliet Taylor
- Genetic Health Service New Zealand, Auckland, New Zealand
| | - Joanne Dixon
- Genetic Health Service New Zealand, Christchurch, New Zealand
| | - Gemma Poke
- Genetic Health Service New Zealand, Wellington, New Zealand
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institutes of Health, Bethesda, Maryland, USA
| | | | | | - Muriel Holder
- Department of Clinical Genetics, Guy's Hospital, London, UK
| | - Sabrina Yum
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Livija Medne
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Susana Quijano-Roy
- Service de Pédiatrie, Centre Hospitalier Universitaire Raymond Poincaré, Garches, France.,Centre de Référence Neuromusculaire GNMH, FILNEMUS, Université de Versailles, Versailles, France
| | - Norma B Romero
- Neuromuscular Morphology Unit and Neuromuscular Pathology Reference Center Paris-Est, Center for Research in Myology, Groupe Hospitalier Universitaire La Pitié-Salpêtrière, Paris, France
| | - Julien Fauré
- UFR de Médecine, Centre Hospitalier Universitaire Grenoble Alpes, Université Grenoble Alpes, Grenoble, France
| | - Lucy Feng
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Laila Bastaki
- Kuwait Medical Genetics Centre, Maternity Hospital, Kuwait City, Kuwait
| | - Mark R Davis
- Department of Diagnostic Genomics, Pathwest Laboratory Medicine, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Rahul Phadke
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, UK.,Great Ormond Street Hospital, London, UK
| | - Caroline A Sewry
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, UK.,Wolfson Centre for Inherited Neuromuscular Diseases, RJAH Orthopaedic Hospital, Oswestry, UK
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institutes of Health, Bethesda, Maryland, USA
| | - Heinz Jungbluth
- Randall Division for Cell and Molecular Biophysics, Muscle Signaling Section, King's College London, London, UK.,Department of Basic and Clinical Neuroscience, IoPPN, King's College London, London, UK.,Department of Anesthesia and Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Christoph Bachmann
- Department of Anesthesia and Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Susan Treves
- Department of Anesthesia and Biomedicine, University Hospital Basel, Basel, Switzerland.,Department of Life Sciences, University of Ferrara, Ferrara, Italy
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, UK.,Great Ormond Street Hospital, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
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43
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Niu J, Dick IE, Yang W, Bamgboye MA, Yue DT, Tomaselli G, Inoue T, Ben-Johny M. Allosteric regulators selectively prevent Ca 2+-feedback of Ca V and Na V channels. eLife 2018; 7:35222. [PMID: 30198845 PMCID: PMC6156082 DOI: 10.7554/elife.35222] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 09/09/2018] [Indexed: 12/31/2022] Open
Abstract
Calmodulin (CaM) serves as a pervasive regulatory subunit of CaV1, CaV2, and NaV1 channels, exploiting a functionally conserved carboxy-tail element to afford dynamic Ca2+-feedback of cellular excitability in neurons and cardiomyocytes. Yet this modularity counters functional adaptability, as global changes in ambient CaM indiscriminately alter its targets. Here, we demonstrate that two structurally unrelated proteins, SH3 and cysteine-rich domain (stac) and fibroblast growth factor homologous factors (fhf) selectively diminish Ca2+/CaM-regulation of CaV1 and NaV1 families, respectively. The two proteins operate on allosteric sites within upstream portions of respective channel carboxy-tails, distinct from the CaM-binding interface. Generalizing this mechanism, insertion of a short RxxK binding motif into CaV1.3 carboxy-tail confers synthetic switching of CaM regulation by Mona SH3 domain. Overall, our findings identify a general class of auxiliary proteins that modify Ca2+/CaM signaling to individual targets allowing spatial and temporal orchestration of feedback, and outline strategies for engineering Ca2+/CaM signaling to individual targets.
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Affiliation(s)
- Jacqueline Niu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, United States
| | - Ivy E Dick
- Department of Physiology, University of Maryland, Baltimore, United States
| | - Wanjun Yang
- Department of Cardiology, Johns Hopkins University, Baltimore, United States
| | | | - David T Yue
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, United States
| | - Gordon Tomaselli
- Department of Cardiology, Johns Hopkins University, Baltimore, United States
| | - Takanari Inoue
- Department of Cell Biology, Johns Hopkins University, Baltimore, United States.,Center for Cell Dynamics, Institute for Basic Biomedical Sciences, Johns Hopkins University, Baltimore, United States
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University, New York, United States
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44
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Stac Proteins Suppress Ca 2+-Dependent Inactivation of Neuronal l-type Ca 2+ Channels. J Neurosci 2018; 38:9215-9227. [PMID: 30201773 DOI: 10.1523/jneurosci.0695-18.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/30/2018] [Accepted: 09/01/2018] [Indexed: 01/28/2023] Open
Abstract
Stac protein (named for its SH3- and cysteine-rich domains) was first identified in brain 20 years ago and is currently known to have three isoforms. Stac2, Stac1, and Stac3 transcripts are found at high, modest, and very low levels, respectively, in the cerebellum and forebrain, but their neuronal functions have been little investigated. Here, we tested the effects of Stac proteins on neuronal, high-voltage-activated Ca2+ channels. Overexpression of the three Stac isoforms eliminated Ca2+-dependent inactivation (CDI) of l-type current in rat neonatal hippocampal neurons (sex unknown), but not CDI of non-l-type current. Using heterologous expression in tsA201 cells (together with β and α2-δ1 auxiliary subunits), we found that CDI for CaV1.2 and CaV1.3 (the predominant, neuronal l-type Ca2+ channels) was suppressed by all three Stac isoforms, whereas CDI for the P/Q channel, CaV2.1, was not. For CaV1.2, the inhibition of CDI by the Stac proteins appeared to involve their direct interaction with the channel's C terminus. Within the Stac proteins, a weakly conserved segment containing ∼100 residues and linking the structurally conserved PKC C1 and SH3_1 domains was sufficient to fully suppress CDI. The presence of CDI for l-type current in control neonatal neurons raised the possibility that endogenous Stac levels are low in these neurons and Western blotting indicated that the expression of Stac2 was substantially increased in adult forebrain and cerebellum compared with neonate. Together, our results indicate that one likely function of neuronal Stac proteins is to tune Ca2+ entry via neuronal l-type channels.SIGNIFICANCE STATEMENT Stac protein, first identified 20 years ago in brain, has recently been found to be essential for proper trafficking and function of the skeletal muscle l-type Ca2+ channel and is the site of mutations causing a severe, inherited human myopathy. In neurons, however, functions for Stac protein have remained unexplored. Here, we report that one likely function of neuronal Stac proteins is tuning Ca2+ entry via l-type, but not that via non-l-type, Ca2+ channels. Moreover, there is a large postnatal increase in protein levels of the major neuronal isoform (Stac2) in forebrain and cerebellum, which could provide developmental regulation of l-type channel Ca2+ signaling in these brain regions.
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45
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Genetic epidemiology of malignant hyperthermia in the UK. Br J Anaesth 2018; 121:944-952. [PMID: 30236257 DOI: 10.1016/j.bja.2018.06.028] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 06/01/2018] [Accepted: 06/20/2018] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Gaps in our understanding of genetic susceptibility to malignant hyperthermia (MH) limit the application and interpretation of genetic diagnosis of the condition. Our aim was to define the prevalence and role of variants in the three genes implicated in MH susceptibility in the largest comprehensively phenotyped MH cohort worldwide. METHODS We initially included one individual from each positive family tested in the UK MH Unit since 1971 to detect variants in RYR1, CACNA1S, or STAC3. Screening for genetic variants has been ongoing since 1991 and has involved a range of techniques, most recently next generation sequencing. We assessed the pathogenicity of variants using standard guidelines, including family segregation studies. The prevalence of recurrent variants of unknown significance was compared with the prevalence reported in a large database of sequence variants in low-risk populations. RESULTS We have confirmed MH susceptibility in 795 independent families, for 722 of which we have a DNA sample. Potentially pathogenic variants were found in 555 families, with 25 RYR1 and one CACNA1S variants previously unclassified recurrent variants significantly over-represented (P<1×10-7) in our cohort compared with the Exome Aggregation Consortium database. There was genotype-phenotype discordance in 86 of 328 families suitable for segregation analysis. We estimate non-RYR1/CACNA1S/STAC3 susceptibility occurs in 14-23% of MH families. CONCLUSIONS Our data provide current estimates of the role of variants in RYR1, CACNA1S, and STAC3 in susceptibility to MH in a predominantly white European population.
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46
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Niu J, Yang W, Yue DT, Inoue T, Ben-Johny M. Duplex signaling by CaM and Stac3 enhances Ca V1.1 function and provides insights into congenital myopathy. J Gen Physiol 2018; 150:1145-1161. [PMID: 29950399 PMCID: PMC6080896 DOI: 10.1085/jgp.201812005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/23/2018] [Accepted: 05/11/2018] [Indexed: 01/24/2023] Open
Abstract
CaV1.1 is essential for skeletal muscle excitation-contraction coupling. Its functional expression is tuned by numerous regulatory proteins, yet underlying modulatory mechanisms remain ambiguous as CaV1.1 fails to function in heterologous systems. In this study, by dissecting channel trafficking versus gating, we evaluated the requirements for functional CaV1.1 in heterologous systems. Although coexpression of the auxiliary β subunit is sufficient for surface-membrane localization, this baseline trafficking is weak, and channels elicit a diminished open probability. The regulatory proteins calmodulin and stac3 independently enhance channel trafficking and gating via their interaction with the CaV1.1 carboxy terminus. Myopathic stac3 mutations weaken channel binding and diminish trafficking. Our findings demonstrate that multiple regulatory proteins orchestrate CaV1.1 function via duplex mechanisms. Our work also furnishes insights into the pathophysiology of stac3-associated congenital myopathy and reveals novel avenues for pharmacological intervention.
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Affiliation(s)
- Jacqueline Niu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
| | - Wanjun Yang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
| | | | - Takanari Inoue
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD
- Department of Cell Biology, Johns Hopkins University, Baltimore, MD
- Center for Cell Dynamics, Institute for Basic Biomedical Sciences, Johns Hopkins University, Baltimore, MD
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY
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47
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Campiglio M, Kaplan MM, Flucher BE. STAC3 incorporation into skeletal muscle triads occurs independent of the dihydropyridine receptor. J Cell Physiol 2018; 233:9045-9051. [PMID: 30071129 PMCID: PMC6334165 DOI: 10.1002/jcp.26767] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/27/2018] [Indexed: 01/02/2023]
Abstract
Excitation‐contraction (EC) coupling in skeletal muscles operates through a physical interaction between the dihydropyridine receptor (DHPR), acting as a voltage sensor, and the ryanodine receptor (RyR1), acting as a calcium release channel. Recently, the adaptor protein SH3 and cysteine‐rich containing protein 3 (STAC3) has been identified as a myopathy disease gene and as an additional essential EC coupling component. STAC3 interacts with DHPR sequences including the critical EC coupling domain and has been proposed to function in linking the DHPR and RyR1. However, we and others demonstrated that incorporation of recombinant STAC3 into skeletal muscle triads critically depends only on the DHPR but not the RyR1. On the contrary, here, we provide evidence that endogenous STAC3 incorporates into triads in the absence of the DHPR in myotubes and muscle fibers of dysgenic mice. This finding demonstrates that STAC3 interacts with additional triad proteins and is consistent with its proposed role in directly or indirectly linking the DHPR with the RyR1.
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Affiliation(s)
- Marta Campiglio
- Department of Physiology, Medical University, Innsbruck, Innsbruck, Austria
| | - Mehmet M Kaplan
- Department of Physiology, Medical University, Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Department of Physiology, Medical University, Innsbruck, Innsbruck, Austria
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48
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Allard B. Evaluation of mutant muscle Ca 2+ channel properties using two different expression systems. J Gen Physiol 2018; 150:897-899. [PMID: 29848491 PMCID: PMC6028501 DOI: 10.1085/jgp.201812095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Allard appraises recent studies investigating the pathological mechanism of hypokalemic periodic paralysis mutations.
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Affiliation(s)
- Bruno Allard
- Institut NeuroMyoGène, Université Lyon 1, Lyon, France
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49
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Abstract
Ryanodine-sensitive intracellular Ca2+ channels (RyRs) open upon binding Ca2+ at cytosolic-facing sites. This results in concerted, self-reinforcing opening of RyRs clustered in specialized regions on the membranes of Ca2+ storage organelles (endoplasmic reticulum and sarcoplasmic reticulum), a process that produces Ca2+-induced Ca2+ release (CICR). The process is optimized to achieve large but brief and localized increases in cytosolic Ca2+ concentration, a feature now believed to be critical for encoding the multiplicity of signals conveyed by this ion. In this paper, I trace the path of research that led to a consensus on the physiological significance of CICR in skeletal muscle, beginning with its discovery. I focus on the approaches that were developed to quantify the contribution of CICR to the Ca2+ increase that results in contraction, as opposed to the flux activated directly by membrane depolarization (depolarization-induced Ca2+ release [DICR]). Although the emerging consensus is that CICR plays an important role alongside DICR in most taxa, its contribution in most mammalian muscles appears to be limited to embryogenesis. Finally, I survey the relevance of CICR, confirmed or plausible, to pathogenesis as well as the multiple questions about activation of release channels that remain unanswered after 50 years.
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Affiliation(s)
- Eduardo Ríos
- Section of Cellular Signaling, Department of Physiology and Biophysics, Rush University School of Medicine, Chicago, IL
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Polster A, Nelson BR, Papadopoulos S, Olson EN, Beam KG. Stac proteins associate with the critical domain for excitation-contraction coupling in the II-III loop of Ca V1.1. J Gen Physiol 2018; 150:613-624. [PMID: 29467163 PMCID: PMC5881444 DOI: 10.1085/jgp.201711917] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 01/05/2018] [Accepted: 01/17/2018] [Indexed: 12/11/2022] Open
Abstract
In skeletal muscle, residues 720-764/5 within the CaV1.1 II-III loop form a critical domain that plays an essential role in transmitting the excitation-contraction (EC) coupling Ca2+ release signal to the type 1 ryanodine receptor (RyR1) in the sarcoplasmic reticulum. However, the identities of proteins that interact with the loop and its critical domain and the mechanism by which the II-III loop regulates RyR1 gating remain unknown. Recent work has shown that EC coupling in skeletal muscle of fish and mice depends on the presence of Stac3, an adaptor protein that is highly expressed only in skeletal muscle. Here, by using colocalization as an indicator of molecular interactions, we show that Stac3, as well as Stac1 and Stac2 (predominantly neuronal Stac isoforms), interact with the II-III loop of CaV1.1. Further, we find that these Stac proteins promote the functional expression of CaV1.1 in tsA201 cells and support EC coupling in Stac3-null myotubes and that Stac3 is the most effective. Coexpression in tsA201 cells reveals that Stac3 interacts only with II-III loop constructs containing the majority of the CaV1.1 critical domain residues. By coexpressing Stac3 in dysgenic (CaV1.1-null) myotubes together with CaV1 constructs whose chimeric II-III loops had previously been tested for functionality, we reveal that the ability of Stac3 to interact with them parallels the ability of these constructs to mediate skeletal type EC coupling. Based on coexpression in tsA201 cells, the interaction of Stac3 with the II-III loop critical domain does not require the presence of the PKC C1 domain in Stac3, but it does require the first of the two SH3 domains. Collectively, our results indicate that activation of RyR1 Ca2+ release by CaV1.1 depends on Stac3 being bound to critical domain residues in the II-III loop.
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Affiliation(s)
- Alexander Polster
- Department of Physiology and Biophysics, University of Colorado Denver, Aurora, CO
| | - Benjamin R Nelson
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Symeon Papadopoulos
- Institute of Vegetative Physiology, University Hospital of Cologne, Cologne, Germany
| | - Eric N Olson
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Kurt G Beam
- Department of Physiology and Biophysics, University of Colorado Denver, Aurora, CO
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