1
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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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2
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Dong K, Liu WC, Su Y, Lyu Y, Huang H, Zheng N, Rogers JA, Nan K. Scalable Electrophysiology of Millimeter-Scale Animals with Electrode Devices. BME FRONTIERS 2023; 4:0034. [PMID: 38435343 PMCID: PMC10907027 DOI: 10.34133/bmef.0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/08/2023] [Indexed: 03/05/2024] Open
Abstract
Millimeter-scale animals such as Caenorhabditis elegans, Drosophila larvae, zebrafish, and bees serve as powerful model organisms in the fields of neurobiology and neuroethology. Various methods exist for recording large-scale electrophysiological signals from these animals. Existing approaches often lack, however, real-time, uninterrupted investigations due to their rigid constructs, geometric constraints, and mechanical mismatch in integration with soft organisms. The recent research establishes the foundations for 3-dimensional flexible bioelectronic interfaces that incorporate microfabricated components and nanoelectronic function with adjustable mechanical properties and multidimensional variability, offering unique capabilities for chronic, stable interrogation and stimulation of millimeter-scale animals and miniature tissue constructs. This review summarizes the most advanced technologies for electrophysiological studies, based on methods of 3-dimensional flexible bioelectronics. A concluding section addresses the challenges of these devices in achieving freestanding, robust, and multifunctional biointerfaces.
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Affiliation(s)
- Kairu Dong
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
- College of Biomedical Engineering & Instrument Science,
Zhejiang University, Hangzhou, 310027, China
| | - Wen-Che Liu
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
| | - Yuyan Su
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- Department of Gastroenterology, Brigham and Women’s Hospital,
Harvard Medical School, Boston, MA 02115, USA
| | - Yidan Lyu
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
| | - Hao Huang
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- College of Chemical and Biological Engineering,
Zhejiang University, Hangzhou 310058, China
| | - Nenggan Zheng
- Qiushi Academy for Advanced Studies,
Zhejiang University, Hangzhou 310027, China
- College of Computer Science and Technology,
Zhejiang University, Hangzhou 310027, China
- State Key Lab of Brain-Machine Intelligence,
Zhejiang University, Hangzhou 310058, China
- CCAI by MOE and Zhejiang Provincial Government (ZJU), Hangzhou 310027, China
| | - John A. Rogers
- Querrey Simpson Institute for Bioelectronics,
Northwestern University, Evanston, IL 60208, USA
- Department of Biomedical Engineering,
Northwestern University, Evanston, IL 60208, USA
- Department of Materials Science and Engineering,
Northwestern University, Evanston, IL 60208, USA
- Department of Mechanical Engineering,
Northwestern University, Evanston, IL 60208, USA
| | - Kewang Nan
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
- Jinhua Institute of Zhejiang University, Jinhua 321299, China
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3
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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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4
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McClenaghan C, Mukadam MA, Roeglin J, Tryon RC, Grabner M, Dayal A, Meyer GA, Nichols CG. Skeletal muscle delimited myopathy and verapamil toxicity in SUR2 mutant mouse models of AIMS. EMBO Mol Med 2023; 15:e16883. [PMID: 37154692 PMCID: PMC10245035 DOI: 10.15252/emmm.202216883] [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: 09/14/2022] [Revised: 04/10/2023] [Accepted: 04/17/2023] [Indexed: 05/10/2023] Open
Abstract
ABCC9-related intellectual disability and myopathy syndrome (AIMS) arises from loss-of-function (LoF) mutations in the ABCC9 gene, which encodes the SUR2 subunit of ATP-sensitive potassium (KATP ) channels. KATP channels are found throughout the cardiovascular system and skeletal muscle and couple cellular metabolism to excitability. AIMS individuals show fatigability, muscle spasms, and cardiac dysfunction. We found reduced exercise performance in mouse models of AIMS harboring premature stop codons in ABCC9. Given the roles of KATP channels in all muscles, we sought to determine how myopathy arises using tissue-selective suppression of KATP and found that LoF in skeletal muscle, specifically, underlies myopathy. In isolated muscle, SUR2 LoF results in abnormal generation of unstimulated forces, potentially explaining painful spasms in AIMS. We sought to determine whether excessive Ca2+ influx through CaV 1.1 channels was responsible for myopathology but found that the Ca2+ channel blocker verapamil unexpectedly resulted in premature death of AIMS mice and that rendering CaV 1.1 channels nonpermeable by mutation failed to reverse pathology; results which caution against the use of calcium channel blockers in AIMS.
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Affiliation(s)
- Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
- Center for Advanced Biotechnology and Medicine, and Departments of Pharmacology and Medicine, Robert Wood Johnson Medical SchoolRutgers UniversityPiscatawayNJUSA
| | - Maya A Mukadam
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Jacob Roeglin
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Robert C Tryon
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Manfred Grabner
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Anamika Dayal
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Gretchen A Meyer
- Program in Physical Therapy, Departments of Orthopaedic Surgery, Neurology and Biomedical EngineeringWashington University School of MedicineSt. LouisMOUSA
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
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5
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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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6
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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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7
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Yuan W, Cui CC, Li J, Xu YH, Fan CE, Chen YC, Fan HW, Hu BX, Shi MY, Sun ZY, Wang P, Ma TX, Zhang Z, Zhu MS, Chen HQ. Intracellular TMEM16A is necessary for myogenesis of skeletal muscle. iScience 2022; 25:105446. [DOI: 10.1016/j.isci.2022.105446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 08/08/2022] [Accepted: 10/21/2022] [Indexed: 11/09/2022] Open
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8
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Sinha S, Elbaz‐Alon Y, Avinoam O. Ca 2+ as a coordinator of skeletal muscle differentiation, fusion and contraction. FEBS J 2022; 289:6531-6542. [PMID: 35689496 PMCID: PMC9795905 DOI: 10.1111/febs.16552] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 05/05/2022] [Accepted: 06/09/2022] [Indexed: 12/30/2022]
Abstract
Muscle regeneration is essential for vertebrate muscle homeostasis and recovery after injury. During regeneration, muscle stem cells differentiate into myocytes, which then fuse with pre-existing muscle fibres. Hence, differentiation, fusion and contraction must be tightly regulated during regeneration to avoid the disastrous consequences of premature fusion of myocytes to actively contracting fibres. Cytosolic calcium (Ca2+ ), which is coupled to both induction of myogenic differentiation and contraction, has more recently been implicated in the regulation of myocyte-to-myotube fusion. In this viewpoint, we propose that Ca2+ -mediated coordination of differentiation, fusion and contraction is a feature selected in the amniotes to facilitate muscle regeneration.
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Affiliation(s)
- Sansrity Sinha
- Department of Biomolecular SciencesWeizmann Institute of ScienceRehovotIsrael
| | - Yael Elbaz‐Alon
- Department of Biomolecular SciencesWeizmann Institute of ScienceRehovotIsrael
| | - Ori Avinoam
- Department of Biomolecular SciencesWeizmann Institute of ScienceRehovotIsrael
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9
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Perni S, Beam K. Junctophilins 1, 2, and 3 all support voltage-induced Ca2+ release despite considerable divergence. J Gen Physiol 2022; 154:212989. [PMID: 35089322 PMCID: PMC9488633 DOI: 10.1085/jgp.202113024] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 01/05/2022] [Indexed: 11/23/2022] Open
Abstract
In skeletal muscle, depolarization of the plasma membrane (PM) causes conformational changes of the calcium channel CaV1.1 that then activate RYR1 to release calcium from the SR. Being independent of extracellular calcium entry, this process is termed voltage-induced calcium release. In skeletal muscle, junctophilins (JPHs) 1 and 2 form the SR–PM junctions at which voltage-induced calcium release occurs. Previous work demonstrated that JPH2 is able to recapitulate voltage-induced calcium release when expressed in HEK293 cells together with CaV1.1, β1a, Stac3, and RYR1. However, it is unknown whether JPH1 and the more distantly related neuronal JPH3 and JPH4 might also function in this manner, a question of interest because different JPH isoforms diverge in their interactions with RYR1. Here, we show that, like JPH2, JPH1 and JPH3, coexpressed with CaV1.1, β1a, Stac3, and RYR1 in HEK293 cells, cause colocalization of CaV1.1 and RYR1 at ER–PM junctions. Furthermore, potassium depolarization elicited cytoplasmic calcium transients in cells in which WT CaV1.1 was replaced with the calcium impermeant mutant CaV1.1(N617D), indicating that JPH1, JPH2, and JPH3 can all support voltage-induced calcium release, despite sequence divergence and differences in interaction with RYR1. Conversely, JPH4-induced ER–PM junctions contain CaV1.1 but not RYR1, and cells expressing JPH4 are unable to produce depolarization-induced calcium transients. Thus, JPHs seem to act primarily to form ER–PM junctions and to recruit the necessary signaling proteins to these junctions but appear not to be directly involved in the functional interactions between these proteins.
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Affiliation(s)
- Stefano Perni
- Department of Physiology and Biophysics, University of Colorado, Anschutz Medical Campus, Aurora, CO
| | - Kurt Beam
- Department of Physiology and Biophysics, University of Colorado, Anschutz Medical Campus, Aurora, CO
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10
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Melzer W. From α1s splicing to γ1 function: A new twist in subunit modulation of the skeletal muscle L-type Ca2+ channel. J Gen Physiol 2022; 154:213270. [PMID: 35674662 PMCID: PMC9184848 DOI: 10.1085/jgp.202213182] [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] [Indexed: 11/20/2022] Open
Abstract
Melzer discusses a recent JGP study showing that alternative splicing of the skeletal muscle L-type calcium channel impacts on a modulatory effect of its γ subunit.
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Affiliation(s)
- Werner Melzer
- Institute of Applied Physiology, Ulm University, Ulm, Germany
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11
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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: 79] [Impact Index Per Article: 26.3] [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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12
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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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13
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Dayal A, Fernández-Quintero ML, Liedl KR, Grabner M. Pore mutation N617D in the skeletal muscle DHPR blocks Ca 2+ influx due to atypical high-affinity Ca 2+ binding. eLife 2021; 10:63435. [PMID: 34061024 PMCID: PMC8184209 DOI: 10.7554/elife.63435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 05/28/2021] [Indexed: 11/13/2022] Open
Abstract
Skeletal muscle excitation-contraction (EC) coupling roots in Ca2+-influx-independent inter-channel signaling between the sarcolemmal dihydropyridine receptor (DHPR) and the ryanodine receptor (RyR1) in the sarcoplasmic reticulum. Although DHPR Ca2+ influx is irrelevant for EC coupling, its putative role in other muscle-physiological and developmental pathways was recently examined using two distinct genetically engineered mouse models carrying Ca2+ non-conducting DHPRs: DHPR(N617D) (Dayal et al., 2017) and DHPR(E1014K) (Lee et al., 2015). Surprisingly, despite complete block of DHPR Ca2+-conductance, histological, biochemical, and physiological results obtained from these two models were contradictory. Here, we characterize the permeability and selectivity properties and henceforth the mechanism of Ca2+ non-conductance of DHPR(N617). Our results reveal that only mutant DHPR(N617D) with atypical high-affinity Ca2+ pore-binding is tight for physiologically relevant monovalent cations like Na+ and K+. Consequently, we propose a molecular model of cooperativity between two ion selectivity rings formed by negatively charged residues in the DHPR pore region.
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Affiliation(s)
- Anamika Dayal
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Manfred Grabner
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
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14
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Balderas-Villalobos J, Steele TWE, Eltit JM. Physiological and Pathological Relevance of Selective and Nonselective Ca 2+ Channels in Skeletal and Cardiac Muscle. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:225-247. [PMID: 35138617 PMCID: PMC10683374 DOI: 10.1007/978-981-16-4254-8_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Contraction of the striated muscle is fundamental for human existence. The action of voluntary skeletal muscle enables activities such as breathing, establishing body posture, and diverse body movements. Additionally, highly precise motion empowers communication, artistic expression, and other activities that define everyday human life. The involuntary contraction of striated muscle is the core function of the heart and is essential for blood flow. Several ion channels are important in the transduction of action potentials to cytosolic Ca2+ signals that enable muscle contraction; however, other ion channels are involved in the progression of muscle pathologies that can impair normal life or threaten it. This chapter describes types of selective and nonselective Ca2+ permeable ion channels expressed in the striated muscle, their participation in different aspects of muscle excitation and contraction, and their relevance to the progression of some pathological states.
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Affiliation(s)
- Jaime Balderas-Villalobos
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Tyler W E Steele
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Jose M Eltit
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.
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15
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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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16
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Divalent cations permeation in a Ca 2+ non-conducting skeletal muscle dihydropyridine receptor mouse model. Cell Calcium 2020; 91:102256. [PMID: 32866694 DOI: 10.1016/j.ceca.2020.102256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/16/2020] [Accepted: 07/19/2020] [Indexed: 11/22/2022]
Abstract
In response to excitation of skeletal muscle fibers, trains of action potentials induce changes in the configuration of the dihydropyridine receptor (DHPR) anchored in the tubular membrane which opens the Ca2+ release channel in the sarcoplasmic reticulum membrane. The DHPR also functions as a voltage-gated Ca2+ channel that conducts L-type Ca2+ currents routinely recorded in mammalian muscle fibers, which role was debated for more than four decades. Recently, to allow a closer look into the role of DHPR Ca2+ influx in mammalian muscle, a knock-in (ki) mouse model (ncDHPR) carrying mutation N617D (adjacent to domain II selectivity filter E) in the DHPRα1S subunit abolishing Ca2+ permeation through the channel was generated [Dayal et al., 2017]. In the present study, the Mn2+ quenching technique was initially intended to be used on voltage-clamped muscle fibers from this mouse to determine whether Ca2+ influx through a pathway distinct from DHPR may occur to compensate for the absence of DHPR Ca2+ influx. Surprisingly, while N617D DHPR muscle fibers of the ki mouse do not conduct Ca2+, Mn2+ entry and subsequent quenching did occur because Mn2+ was able to permeate and produce L-type currents through N617D DHPR. N617D DHPR was also found to conduct Ba2+ and Ba2+ currents were strongly blocked by external Ca2+. Ba2+ permeation was smaller, current kinetics slower and Ca2+ block more potent than in wild-type DHPR. These results indicate that residue N617 when replaced by the negatively charged residue D is suitably located at entrance of the pore to trap external Ca2+ impeding in this way permeation. Because Ba2+ binds with lower affinity to D, Ba2+ currents occur, but with reduced amplitudes as compared to Ba2+ currents through wild-type channels. We conclude that mutations located outside the selectivity filter influence channel permeation and possibly channel gating in a fully differentiated skeletal muscle environment.
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17
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Flucher BE. Skeletal muscle Ca V1.1 channelopathies. Pflugers Arch 2020; 472:739-754. [PMID: 32222817 PMCID: PMC7351834 DOI: 10.1007/s00424-020-02368-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 12/15/2022]
Abstract
CaV1.1 is specifically expressed in skeletal muscle where it functions as voltage sensor of skeletal muscle excitation-contraction (EC) coupling independently of its functions as L-type calcium channel. Consequently, all known CaV1.1-related diseases are muscle diseases and the molecular and cellular disease mechanisms relate to the dual functions of CaV1.1 in this tissue. To date, four types of muscle diseases are known that can be linked to mutations in the CACNA1S gene or to splicing defects. These are hypo- and normokalemic periodic paralysis, malignant hyperthermia susceptibility, CaV1.1-related myopathies, and myotonic dystrophy type 1. In addition, the CaV1.1 function in EC coupling is perturbed in Native American myopathy, arising from mutations in the CaV1.1-associated protein STAC3. Here, we first address general considerations concerning the possible roles of CaV1.1 in disease and then discuss the state of the art regarding the pathophysiology of the CaV1.1-related skeletal muscle diseases with an emphasis on molecular disease mechanisms.
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Affiliation(s)
- Bernhard E Flucher
- Department of Physiology and Medical Biophysics, Medical University Innsbruck, Schöpfstraße 41, A6020, Innsbruck, Austria.
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18
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Yan J, Chen S, Zuo Z, He C, Yi M. Graphene oxide quantum dot exposure induces abnormalities in locomotor activities and mechanisms in zebrafish (
Danio rerio
). J Appl Toxicol 2020; 40:794-803. [DOI: 10.1002/jat.3944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/21/2019] [Accepted: 12/23/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Jinhui Yan
- School of KinesiologyShanghai University of Sport Shanghai China
- College of Physical EducationJimei University Xiamen Fujian China
| | - Shujing Chen
- State Key Laboratory of Cellular Stress Biology, School of Life SciencesXiamen University Xiamen Fujian China
| | - Zhenghong Zuo
- State Key Laboratory of Cellular Stress Biology, School of Life SciencesXiamen University Xiamen Fujian China
| | - Chengyong He
- State Key Laboratory of Cellular Stress Biology, School of Life SciencesXiamen University Xiamen Fujian China
| | - Muqing Yi
- School of KinesiologyShanghai University of Sport Shanghai China
- Center for Sports NutritionNational Institute of Sports Medicine Beijing China
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19
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Mackrill JJ, Shiels HA. Evolution of Excitation-Contraction Coupling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:281-320. [DOI: 10.1007/978-3-030-12457-1_12] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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20
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Targeted mutagenesis of the ryanodine receptor by Platinum TALENs causes slow swimming behaviour in Pacific bluefin tuna (Thunnus orientalis). Sci Rep 2019; 9:13871. [PMID: 31554877 PMCID: PMC6761128 DOI: 10.1038/s41598-019-50418-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 09/05/2019] [Indexed: 11/08/2022] Open
Abstract
In bluefin tuna aquaculture, high mortalities of hatchery-reared juveniles occur in sea cages owing to wall collisions that are caused by high-speed swimming in panic due to changes in illuminance. Here, we report that targeted gene mutagenesis of the ryanodine receptor (RyR1b), which allows the sarcoplasmic reticulum to release Ca2+ in fast skeletal muscle, using highly active Platinum TALENs caused slow swimming behaviour in response to external stimuli in Pacific bluefin tuna (PBT) larvae. This characteristic would be a useful trait to prevent wall collisions in aquaculture production. A pair of Platinum TALENs targeting exons 2 and 43 of the PBT ryr1b gene induced deletions in each TALEN target site of the injected embryos with extremely high efficiency. In addition, ryr1b expression was significantly decreased in the mutated G0 larvae at 7 days after hatching (DAH). A touch-evoked escape behaviour assay revealed that the ryr1b-mutated PBT larvae swam away much less efficiently in response to mechanosensory stimulation at 7 DAH than did the wild-type larvae. Our results demonstrate that genome editing technologies are effective tools for determining the functional characterization of genes in a comparatively short period, and create avenues for facilitating genetic studies and breeding of bluefin tuna species.
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21
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Dayal A, Ng SFJ, Grabner M. Ca 2+-activated Cl - channel TMEM16A/ANO1 identified in zebrafish skeletal muscle is crucial for action potential acceleration. Nat Commun 2019; 10:115. [PMID: 30631052 PMCID: PMC6328546 DOI: 10.1038/s41467-018-07918-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 12/03/2018] [Indexed: 01/16/2023] Open
Abstract
The Ca2+-activated Cl− channel (CaCC) TMEM16A/Anoctamin 1 (ANO1) is expressed in gastrointestinal epithelia and smooth muscle cells where it mediates secretion and intestinal motility. However, ANO1 Cl− conductance has never been reported to play a role in skeletal muscle. Here we show that ANO1 is robustly expressed in the highly evolved skeletal musculature of the euteleost species zebrafish. We characterised ANO1 as bonafide CaCC which is activated close to maximum by Ca2+ ions released from the SR during excitation-contraction (EC) coupling. Consequently, our study addressed the question about the physiological advantage of implementation of ANO1 into the euteleost skeletal-muscle EC coupling machinery. Our results reveal that Cl− influx through ANO1 plays an essential role in restricting the width of skeletal-muscle action potentials (APs) by accelerating the repolarisation phase. Resulting slimmer APs enable higher AP-frequencies and apparently tighter controlled, faster and stronger muscle contractions, crucial for high speed movements. The Ca2+-activated Cl- channel TMEM16A/Anoctamin 1 (ANO1) mediates secretion and intestinal motility in gastrointestinal epithelia and smooth muscle cells. Here, the authors show a role for ANO1 in zebrafish skeletal muscle which is activated by SR Ca2+ release during excitation-contraction coupling.
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Affiliation(s)
- Anamika Dayal
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria.
| | - Shu Fun J Ng
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria
| | - Manfred Grabner
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria.
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22
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Linsley JW, Hsu IU, Wang W, Kuwada JY. Transport of the alpha subunit of the voltage gated L-type calcium channel through the sarcoplasmic reticulum occurs prior to localization to triads and requires the beta subunit but not Stac3 in skeletal muscles. Traffic 2018; 18:622-632. [PMID: 28697281 DOI: 10.1111/tra.12502] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 07/06/2017] [Accepted: 07/06/2017] [Indexed: 12/20/2022]
Abstract
Contraction of skeletal muscle is initiated by excitation-contraction (EC) coupling during which membrane voltage is transduced to intracellular Ca2+ release. EC coupling requires L-type voltage gated Ca2+ channels (the dihydropyridine receptor or DHPR) located at triads, which are junctions between the transverse (T) tubule and sarcoplasmic reticulum (SR) membranes, that sense membrane depolarization in the T tubule membrane. Reduced EC coupling is associated with ageing, and disruptions of EC coupling result in congenital myopathies for which there are few therapies. The precise localization of DHPRs to triads is critical for EC coupling, yet trafficking of the DHPR to triads is not well understood. Using dynamic imaging of zebrafish muscle fibers, we find that DHPR is transported along the longitudinal SR in a microtubule-independent mechanism. Furthermore, transport of DHPR in the SR membrane is differentially affected in null mutants of Stac3 or DHPRβ, two essential components of EC coupling. These findings reveal previously unappreciated features of DHPR motility within the SR prior to assembly at triads.
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Affiliation(s)
- Jeremy W Linsley
- Cell and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan.,Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - I-Uen Hsu
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Wenjia Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - John Y Kuwada
- Cell and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan.,Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan
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23
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Wu F, Quinonez M, DiFranco M, Cannon SC. Stac3 enhances expression of human Ca V1.1 in Xenopus oocytes and reveals gating pore currents in HypoPP mutant channels. J Gen Physiol 2018; 150:475-489. [PMID: 29386226 PMCID: PMC5839724 DOI: 10.1085/jgp.201711962] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/03/2018] [Indexed: 01/24/2023] Open
Abstract
Hypokalemic periodic paralysis (HypoPP) is thought to be caused by an aberrant inward current through the voltage sensors of mutant Na+ or Ca2+ channels. Wu et al. use Stac3 to enhance the membrane expression of two HypoPP CaV1.1 mutants in oocytes and find that both support gating pore currents. Mutations of CaV1.1, the pore-forming subunit of the L-type Ca2+ channel in skeletal muscle, are an established cause of hypokalemic periodic paralysis (HypoPP). However, functional assessment of HypoPP mutant channels has been hampered by difficulties in achieving sufficient plasma membrane expression in cells that are not of muscle origin. In this study, we show that coexpression of Stac3 dramatically increases the expression of human CaV1.1 (plus α2-δ1b and β1a subunits) at the plasma membrane of Xenopus laevis oocytes. In voltage-clamp studies with the cut-open oocyte clamp, we observe ionic currents on the order of 1 μA and gating charge displacements of ∼0.5–1 nC. Importantly, this high expression level is sufficient to ascertain whether HypoPP mutant channels are leaky because of missense mutations at arginine residues in S4 segments of the voltage sensor domains. We show that R528H and R528G in S4 of domain II both support gating pore currents, but unlike other R/H HypoPP mutations, R528H does not conduct protons. Stac3-enhanced membrane expression of CaV1.1 in oocytes increases the throughput for functional studies of disease-associated mutations and is a new platform for investigating the voltage-dependent properties of CaV1.1 without the complexity of the transverse tubule network in skeletal muscle.
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Affiliation(s)
- Fenfen Wu
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marbella Quinonez
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marino DiFranco
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
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24
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Beqollari D, Dockstader K, Bannister RA. A skeletal muscle L-type Ca 2+ channel with a mutation in the selectivity filter (Ca V1.1 E1014K) conducts K<sup/>. J Biol Chem 2018; 293:3126-3133. [PMID: 29326166 DOI: 10.1074/jbc.m117.812446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 01/04/2018] [Indexed: 12/17/2022] Open
Abstract
A glutamate-to-lysine substitution at position 1014 within the selectivity filter of the skeletal muscle L-type Ca2+ channel (CaV1.1) abolishes Ca2+ flux through the channel pore. Mice engineered to exclusively express the mutant channel display accelerated muscle fatigue, changes in muscle composition, and altered metabolism relative to wildtype littermates. By contrast, mice expressing another mutant CaV1.1 channel that is impermeable to Ca2+ (CaV1.1 N617D) have shown no detectable phenotypic differences from wildtype mice to date. The major biophysical difference between the CaV1.1 E1014K and CaV1.1 N617D mutants elucidated thus far is that the former channel conducts robust Na+ and Cs+ currents in patch-clamp experiments, but neither of these monovalent conductances seems to be of relevance in vivo Thus, the basis for the different phenotypes of these mutants has remained enigmatic. We now show that CaV1.1 E1014K readily conducts 1,4-dihydropyridine-sensitive K+ currents at depolarizing test potentials, whereas CaV1.1 N617D does not. Our observations, coupled with a large body of work by others regarding the role of K+ accumulation in muscle fatigue, raise the possibility that the introduction of an additional K+ flux from the myoplasm into the transverse-tubule lumen accelerates the onset of fatigue and precipitates the metabolic changes observed in CaV1.1 E1014K muscle. These results, highlighting an unexpected consequence of a channel mutation, may help define the complex mechanisms underlying skeletal muscle fatigue and related dysfunctions.
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Affiliation(s)
- Donald Beqollari
- From the Department of Medicine, Cardiology Division, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Karen Dockstader
- From the Department of Medicine, Cardiology Division, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - Roger A Bannister
- From the Department of Medicine, Cardiology Division, University of Colorado School of Medicine, Aurora, Colorado 80045
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25
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Franzini-Armstrong C. The relationship between form and function throughout the history of excitation-contraction coupling. J Gen Physiol 2018; 150:189-210. [PMID: 29317466 PMCID: PMC5806676 DOI: 10.1085/jgp.201711889] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Franzini-Armstrong reviews the development of the excitation–contraction coupling field over time. The concept of excitation–contraction coupling is almost as old as Journal of General Physiology. It was understood as early as the 1940s that a series of stereotyped events is responsible for the rapid contraction response of muscle fibers to an initial electrical event at the surface. These early developments, now lost in what seems to be the far past for most young investigators, have provided an endless source of experimental approaches. In this Milestone in Physiology, I describe in detail the experiments and concepts that introduced and established the field of excitation–contraction coupling in skeletal muscle. More recent advances are presented in an abbreviated form, as readers are likely to be familiar with recent work in the field.
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Affiliation(s)
- Clara Franzini-Armstrong
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA
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26
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Abstract
Every cell within living organisms actively maintains an intracellular Na+ concentration that is 10-12 times lower than the extracellular concentration. The cells then utilize this transmembrane Na+ concentration gradient as a driving force to produce electrical signals, sometimes in the form of action potentials. The protein family comprising voltage-gated sodium channels (NaVs) is essential for such signaling and enables cells to change their status in a regenerative manner and to rapidly communicate with one another. NaVs were first predicted in squid and were later identified through molecular biology in the electric eel. Since then, these proteins have been discovered in organisms ranging from bacteria to humans. Recent research has succeeded in decoding the amino acid sequences of a wide variety of NaV family members, as well as the three-dimensional structures of some. These studies and others have uncovered several of the major steps in the functional and structural transition of NaV proteins that has occurred along the course of the evolutionary history of organisms. Here we present an overview of the molecular evolutionary innovations that established present-day NaV α subunits and discuss their contribution to the evolutionary changes in animal bodies.
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Affiliation(s)
- Atsuo Nishino
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan.
| | - Yasushi Okamura
- Integrative Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
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27
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Flucher BE, Tuluc P. How and why are calcium currents curtailed in the skeletal muscle voltage-gated calcium channels? J Physiol 2017; 595:1451-1463. [PMID: 27896815 PMCID: PMC5330888 DOI: 10.1113/jp273423] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/24/2016] [Indexed: 01/09/2023] Open
Abstract
Voltage‐gated calcium channels represent the sole mechanism converting electrical signals of excitable cells into cellular functions such as contraction, secretion and gene regulation. Specific voltage‐sensing domains detect changes in membrane potential and control channel gating. Calcium ions entering through the channel function as second messengers regulating cell functions, with the exception of skeletal muscle, where CaV1.1 essentially does not function as a channel but activates calcium release from intracellular stores. It has long been known that calcium currents are dispensable for skeletal muscle contraction. However, the questions as to how and why the channel function of CaV1.1 is curtailed remained obscure until the recent discovery of a developmental CaV1.1 splice variant with normal channel functions. This discovery provided new means to study the molecular mechanisms regulating the channel gating and led to the understanding that in skeletal muscle, calcium currents need to be restricted to allow proper regulation of fibre type specification and to prevent mitochondrial damage.
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Affiliation(s)
- Bernhard E Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, Austria
| | - Petronel Tuluc
- Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Austria
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28
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The Ca 2+ influx through the mammalian skeletal muscle dihydropyridine receptor is irrelevant for muscle performance. Nat Commun 2017; 8:475. [PMID: 28883413 PMCID: PMC5589907 DOI: 10.1038/s41467-017-00629-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 07/14/2017] [Indexed: 01/01/2023] Open
Abstract
Skeletal muscle excitation-contraction (EC) coupling is initiated by sarcolemmal depolarization, which is translated into a conformational change of the dihydropyridine receptor (DHPR), which in turn activates sarcoplasmic reticulum (SR) Ca2+ release to trigger muscle contraction. During EC coupling, the mammalian DHPR embraces functional duality, as voltage sensor and L-type Ca2+ channel. Although its unique role as voltage sensor for conformational EC coupling is firmly established, the conventional function as Ca2+ channel is still enigmatic. Here we show that Ca2+ influx via DHPR is not necessary for muscle performance by generating a knock-in mouse where DHPR-mediated Ca2+ influx is eliminated. Homozygous knock-in mice display SR Ca2+ release, locomotor activity, motor coordination, muscle strength and susceptibility to fatigue comparable to wild-type controls, without any compensatory regulation of multiple key proteins of the EC coupling machinery and Ca2+ homeostasis. These findings support the hypothesis that the DHPR-mediated Ca2+ influx in mammalian skeletal muscle is an evolutionary remnant.In mammalian skeletal muscle, the DHPR functions as a voltage sensor to trigger muscle contraction and as a Ca2+ channel. Here the authors show that mice where Ca2+ influx through the DHPR is eliminated display no difference in skeletal muscle function, suggesting that the Ca2+ influx through this channel is vestigial.
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Xiyuan Z, Fink RHA, Mosqueira M. NO-sGC Pathway Modulates Ca 2+ Release and Muscle Contraction in Zebrafish Skeletal Muscle. Front Physiol 2017; 8:607. [PMID: 28878687 PMCID: PMC5572320 DOI: 10.3389/fphys.2017.00607] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 08/07/2017] [Indexed: 11/26/2022] Open
Abstract
Vertebrate skeletal muscle contraction and relaxation is a complex process that depends on Ca2+ ions to promote the interaction of actin and myosin. This process can be modulated by nitric oxide (NO), a gas molecule synthesized endogenously by (nitric oxide synthase) NOS isoforms. At nanomolar concentrations NO activates soluble guanylate cyclase (sGC), which in turn activates protein kinase G via conversion of GTP into cyclic GMP. Alternatively, NO post-translationally modifies proteins via S-nitrosylation of the thiol group of cysteine. However, the mechanisms of action of NO on Ca2+ homeostasis during muscle contraction are not fully understood and we hypothesize that NO exerts its effects on Ca2+ homeostasis in skeletal muscles mainly through negative modulation of Ca2+ release and Ca2+ uptake via the NO-sGC-PKG pathway. To address this, we used 5–7 days-post fecundation-larvae of zebrafish, a well-established animal model for physiological and pathophysiological muscle activity. We evaluated the response of muscle contraction and Ca2+ transients in presence of SNAP, a NO-donor, or L-NAME, an unspecific NOS blocker in combination with specific blockers of key proteins of Ca2+ homeostasis. We also evaluate the expression of NOS in combination with dihydropteridine receptor, ryanodine receptor and sarco/endoplasmic reticulum Ca2+ ATPase. We concluded that endogenous NO reduced force production through negative modulation of Ca2+ transients via the NO-sGC pathway. This effect could be reversed using an unspecific NOS blocker or sGC blocker.
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Affiliation(s)
- Zhou Xiyuan
- Medical Biophysics Unit, Institute of Physiology and Pathophysiology, Heidelberg University HospitalHeidelberg, Germany.,Department of Traumatic Surgery, TongJi Hospital affiliated to TongJi Medical College, Huazhong University of Science and TechnologyWuhan, China
| | - Rainer H A Fink
- Medical Biophysics Unit, Institute of Physiology and Pathophysiology, Heidelberg University HospitalHeidelberg, Germany
| | - Matias Mosqueira
- Medical Biophysics Unit, Institute of Physiology and Pathophysiology, Heidelberg University HospitalHeidelberg, Germany
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Congenital myopathy results from misregulation of a muscle Ca2+ channel by mutant Stac3. Proc Natl Acad Sci U S A 2016; 114:E228-E236. [PMID: 28003463 DOI: 10.1073/pnas.1619238114] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Skeletal muscle contractions are initiated by an increase in Ca2+ released during excitation-contraction (EC) coupling, and defects in EC coupling are associated with human myopathies. EC coupling requires communication between voltage-sensing dihydropyridine receptors (DHPRs) in transverse tubule membrane and Ca2+ release channel ryanodine receptor 1 (RyR1) in the sarcoplasmic reticulum (SR). Stac3 protein (SH3 and cysteine-rich domain 3) is an essential component of the EC coupling apparatus and a mutation in human STAC3 causes the debilitating Native American myopathy (NAM), but the nature of how Stac3 acts on the DHPR and/or RyR1 is unknown. Using electron microscopy, electrophysiology, and dynamic imaging of zebrafish muscle fibers, we find significantly reduced DHPR levels, functionality, and stability in stac3 mutants. Furthermore, stac3NAM myofibers exhibited increased caffeine-induced Ca2+ release across a wide range of concentrations in the absence of altered caffeine sensitivity as well as increased Ca2+ in internal stores, which is consistent with increased SR luminal Ca2+ These findings define critical roles for Stac3 in EC coupling and human disease.
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Schrötter K, Dayal A, Grabner M. The mammalian skeletal muscle DHPR has larger Ca 2+ conductance and is phylogenetically ancient to the early ray-finned fish sterlet (Acipenser ruthenus). Cell Calcium 2016; 61:22-31. [PMID: 27793347 PMCID: PMC5538450 DOI: 10.1016/j.ceca.2016.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/21/2016] [Accepted: 10/21/2016] [Indexed: 01/01/2023]
Abstract
The L-type Ca2+ channel or dihydropyridine receptor (DHPR) in vertebrate skeletal muscle is responsible for sensing sarcolemmal depolarizations and transducing this signal to the sarcoplasmic Ca2+ release channel RyR1 via conformational coupling to initiate muscle contraction. During this excitation-contraction (EC) coupling process there is a slow Ca2+ current through the mammalian DHPR which is fully missing in euteleost fishes. In contrast to ancestral evolutionary stages where skeletal muscle EC coupling is still depended on Ca2+-induced Ca2+-release (CICR), it is possible that the DHPR Ca2+ conductivity during mammalian (conformational) EC coupling was retained as an evolutionary remnant (vestigiality). Here, we wanted to test the hypothesis that due to the lack of evolutionary pressure in post-CICR species skeletal muscle DHPR Ca2+ conductivity gradually reduced as evolution progressed. Interestingly, we identified that the DHPR of the early ray-finned fish sterlet (Acipenser ruthenus) is phylogenetically positioned above the mammalian rabbit DHPR which retained robust Ca2+ conductivity, but below the euteleost zebrafish DHPR which completely lost Ca2+ conductivity. Remarkably, our results revealed that sterlet DHPR still retained the Ca2+ conductivity but currents are significantly reduced compared to rabbit. This decrease is due to lower DHPR membrane expression similar to zebrafish, as well as due to reduced channel open probability (Po). In both these fish species the lower DHPR expression density is partially compensated by higher efficacy of DHPR-RyR1 coupling. The complete loss of Po in zebrafish and other euteleost species was presumably based on the teleost specific 3rd round of genome duplication (Ts3R). Ts3R headed into the appearance of two skeletal muscle DHPR isoforms which finally, together with the radiation of the euteleost clade, fully lost the Po.
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Affiliation(s)
- Kai Schrötter
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria
| | - Anamika Dayal
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria
| | - Manfred Grabner
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria.
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Bannister RA. Bridging the myoplasmic gap II: more recent advances in skeletal muscle excitation-contraction coupling. ACTA ACUST UNITED AC 2016; 219:175-82. [PMID: 26792328 DOI: 10.1242/jeb.124123] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the transmission of an intermolecular signal from the voltage-sensing regions of the L-type Ca(2+) channel (Ca(V)1.1) in the plasma membrane to the channel pore of the type 1 ryanodine receptor (RyR1) nearly 10 nm away in the membrane of the sarcoplasmic reticulum (SR). Even though the roles of Ca(V)1.1 and RyR1 as voltage sensor and SR Ca(2+) release channel, respectively, have been established for nearly 25 years, the mechanism underlying communication between these two channels remains undefined. In the course of this article, I will review current viewpoints on this topic with particular emphasis on recent studies.
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Affiliation(s)
- Roger A Bannister
- Department of Medicine-Cardiology Division, University of Colorado Denver-Anschutz Medical Campus, 12700 East 19th Avenue, Room 8006, B-139, Aurora, CO 80045, USA
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Stac3 has a direct role in skeletal muscle-type excitation-contraction coupling that is disrupted by a myopathy-causing mutation. Proc Natl Acad Sci U S A 2016; 113:10986-91. [PMID: 27621462 DOI: 10.1073/pnas.1612441113] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In skeletal muscle, conformational coupling between CaV1.1 in the plasma membrane and type 1 ryanodine receptor (RyR1) in the sarcoplasmic reticulum (SR) is thought to underlie both excitation-contraction (EC) coupling Ca(2+) release from the SR and retrograde coupling by which RyR1 increases the magnitude of the Ca(2+) current via CaV1.1. Recent work has shown that EC coupling fails in muscle from mice and fish null for the protein Stac3 (SH3 and cysteine-rich domain 3) but did not establish the functional role of Stac3 in the CaV1.1-RyR1 interaction. We investigated this using both tsA201 cells and Stac3 KO myotubes. While confirming in tsA201 cells that Stac3 could support surface expression of CaV1.1 (coexpressed with its auxiliary β1a and α2-δ1 subunits) and the generation of large Ca(2+) currents, we found that without Stac3 the auxiliary γ1 subunit also supported membrane expression of CaV1.1/β1a/α2-δ1, but that this combination generated only tiny Ca(2+) currents. In Stac3 KO myotubes, there was reduced, but still substantial CaV1.1 in the plasma membrane. However, the CaV1.1 remaining in Stac3 KO myotubes did not generate appreciable Ca(2+) currents or EC coupling Ca(2+) release. Expression of WT Stac3 in Stac3 KO myotubes fully restored Ca(2+) currents and EC coupling Ca(2+) release, whereas expression of Stac3W280S (containing the Native American myopathy mutation) partially restored Ca(2+) currents but only marginally restored EC coupling. We conclude that membrane trafficking of CaV1.1 is facilitated by, but does not require, Stac3, and that Stac3 is directly involved in conformational coupling between CaV1.1 and RyR1.
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Georgiou DK, Dagnino-Acosta A, Lee CS, Griffin DM, Wang H, Lagor WR, Pautler RG, Dirksen RT, Hamilton SL. Ca2+ Binding/Permeation via Calcium Channel, CaV1.1, Regulates the Intracellular Distribution of the Fatty Acid Transport Protein, CD36, and Fatty Acid Metabolism. J Biol Chem 2015; 290:23751-65. [PMID: 26245899 DOI: 10.1074/jbc.m115.643544] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Indexed: 01/08/2023] Open
Abstract
Ca(2+) permeation and/or binding to the skeletal muscle L-type Ca(2+) channel (CaV1.1) facilitates activation of Ca(2+)/calmodulin kinase type II (CaMKII) and Ca(2+) store refilling to reduce muscle fatigue and atrophy (Lee, C. S., Dagnino-Acosta, A., Yarotskyy, V., Hanna, A., Lyfenko, A., Knoblauch, M., Georgiou, D. K., Poché, R. A., Swank, M. W., Long, C., Ismailov, I. I., Lanner, J., Tran, T., Dong, K., Rodney, G. G., Dickinson, M. E., Beeton, C., Zhang, P., Dirksen, R. T., and Hamilton, S. L. (2015) Skelet. Muscle 5, 4). Mice with a mutation (E1014K) in the Cacna1s (α1 subunit of CaV1.1) gene that abolishes Ca(2+) binding within the CaV1.1 pore gain more body weight and fat on a chow diet than control mice, without changes in food intake or activity, suggesting that CaV1.1-mediated CaMKII activation impacts muscle energy expenditure. We delineate a pathway (Cav1.1→ CaMKII→ NOS) in normal skeletal muscle that regulates the intracellular distribution of the fatty acid transport protein, CD36, altering fatty acid metabolism. The consequences of blocking this pathway are decreased mitochondrial β-oxidation and decreased energy expenditure. This study delineates a previously uncharacterized CaV1.1-mediated pathway that regulates energy utilization in skeletal muscle.
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Affiliation(s)
- Dimitra K Georgiou
- From the Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and
| | - Adan Dagnino-Acosta
- From the Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and
| | - Chang Seok Lee
- From the Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and
| | - Deric M Griffin
- From the Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and
| | - Hui Wang
- From the Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and
| | - William R Lagor
- From the Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and
| | - Robia G Pautler
- From the Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and
| | - Robert T Dirksen
- the Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642
| | - Susan L Hamilton
- From the Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030 and
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Campiglio M, Flucher BE. The role of auxiliary subunits for the functional diversity of voltage-gated calcium channels. J Cell Physiol 2015; 230:2019-31. [PMID: 25820299 PMCID: PMC4672716 DOI: 10.1002/jcp.24998] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 03/23/2015] [Indexed: 11/18/2022]
Abstract
Voltage-gated calcium channels (VGCCs) represent the sole mechanism to convert membrane depolarization into cellular functions like secretion, contraction, or gene regulation. VGCCs consist of a pore-forming α1 subunit and several auxiliary channel subunits. These subunits come in multiple isoforms and splice-variants giving rise to a stunning molecular diversity of possible subunit combinations. It is generally believed that specific auxiliary subunits differentially regulate the channels and thereby contribute to the great functional diversity of VGCCs. If auxiliary subunits can associate and dissociate from pre-existing channel complexes, this would allow dynamic regulation of channel properties. However, most auxiliary subunits modulate current properties very similarly, and proof that any cellular calcium channel function is indeed modulated by the physiological exchange of auxiliary subunits is still lacking. In this review we summarize available information supporting a differential modulation of calcium channel functions by exchange of auxiliary subunits, as well as experimental evidence in support of alternative functions of the auxiliary subunits. At the heart of the discussion is the concept that, in their native environment, VGCCs function in the context of macromolecular signaling complexes and that the auxiliary subunits help to orchestrate the diverse protein–protein interactions found in these calcium channel signalosomes. Thus, in addition to a putative differential modulation of current properties, differential subcellular targeting properties and differential protein–protein interactions of the auxiliary subunits may explain the need for their vast molecular diversity. J. Cell. Physiol. 999: 00–00, 2015. © 2015 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc. J. Cell. Physiol. 230: 2019–2031, 2015. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Marta Campiglio
- Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
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Maves L. Recent advances using zebrafish animal models for muscle disease drug discovery. Expert Opin Drug Discov 2014; 9:1033-45. [PMID: 24931439 DOI: 10.1517/17460441.2014.927435] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Animal models have enabled great progress in the discovery and understanding of pharmacological approaches for treating muscle diseases like Duchenne muscular dystrophy. AREAS COVERED With this article, the author provides the reader with a description of the zebrafish animal model, which has been employed to identify and study pharmacological approaches to muscle disease. In particular, the author focuses on how both large-scale chemical screens and targeted drug treatment studies have established zebrafish as an important model for muscle disease drug discovery. EXPERT OPINION There are a number of opportunities arising for the use of zebrafish models for further developing pharmacological approaches to muscle diseases, including studying drug combination therapies and utilizing genome editing to engineer zebrafish muscle disease models. It is the author's particular belief that the availability of a wide range of zebrafish transgenic strains for labeling immune cell types, combined with live imaging and drug treatment of muscle disease models, should allow for new elegant studies demonstrating how pharmacological approaches might influence inflammation and the immune response in muscle disease.
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Affiliation(s)
- Lisa Maves
- University of Washington School of Medicine, Department of Pediatrics, Division of Cardiology , Seattle, WA , USA
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37
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Melzer W. Skeletal muscle fibers: Inactivated or depleted after long depolarizations? ACTA ACUST UNITED AC 2014; 141:517-20. [PMID: 23630336 PMCID: PMC3639573 DOI: 10.1085/jgp.201310997] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Werner Melzer
- Institute of Applied Physiology, Ulm University, D-89081 Ulm, Germany.
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38
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Horstick EJ, Gibbs EM, Li X, Davidson AE, Dowling JJ. Analysis of embryonic and larval zebrafish skeletal myofibers from dissociated preparations. J Vis Exp 2013:e50259. [PMID: 24300240 DOI: 10.3791/50259] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The zebrafish has proven to be a valuable model system for exploring skeletal muscle function and for studying human muscle diseases. Despite the many advantages offered by in vivo analysis of skeletal muscle in the zebrafish, visualizing the complex and finely structured protein milieu responsible for muscle function, especially in whole embryos, can be problematic. This hindrance stems from the small size of zebrafish skeletal muscle (60 μm) and the even smaller size of the sarcomere. Here we describe and demonstrate a simple and rapid method for isolating skeletal myofibers from zebrafish embryos and larvae. We also include protocols that illustrate post preparation techniques useful for analyzing muscle structure and function. Specifically, we detail the subsequent immunocytochemical localization of skeletal muscle proteins and the qualitative analysis of stimulated calcium release via live cell calcium imaging. Overall, this video article provides a straight-forward and efficient method for the isolation and characterization of zebrafish skeletal myofibers, a technique which provides a conduit for myriad subsequent studies of muscle structure and function.
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Affiliation(s)
- Eric J Horstick
- Departments of Pediatrics and Neurology, University of Michigan
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Senatore A, Spafford JD. A uniquely adaptable pore is consistent with NALCN being an ion sensor. Channels (Austin) 2013; 7:60-8. [PMID: 23442378 PMCID: PMC3667885 DOI: 10.4161/chan.23981] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
NALCN is an intriguing, orphan ion channel among the 4x6TM family of related voltage-gated cation channels, sharing a common architecture of four homologous domains consisting of six transmembrane helices, separated by three cytoplasmic linkers and delimited by N and C-terminal ends. NALCN is one of the shortest 4x6TM family members, lacking much of the variation that provides the diverse palate of gating features, and tissue specific adaptations of sodium and calcium channels. NALCN's most distinctive feature is that that it possesses a highly adaptable pore with a calcium-like EEEE selectivity filter in radially symmetrical animals and a more sodium-like EEKE or EKEE selectivity filter in bilaterally symmetrical animals including vertebrates. Two lineages of animals evolved alternative calcium-like EEEE and sodium-like EEKE / EKEE pores, spliced to regulate NALCN functions in differing cellular environments, such as muscle (heart and skeletal) and secretory tissue (brain and glands), respectively. A highly adaptable pore in an otherwise conserved ion channel in the 4x6TM channel family is not consistent with a role for NALCN in directly gating a significant ion conductance that can be either sodium ions or calcium ions. NALCN was proposed to be an expressible Gd ( 3+) -sensitive, NMDG (+) -impermeant, non-selective and ohmic leak conductance in HEK-293T cells, but we were unable to distinguish these reported currents from leaky patch currents (ILP) in control HEK-293T cells. We suggest that NALCN functions as a sensor for the much larger UNC80/UNC79 complex, in a manner consistent with the coupling mechanism known for other weakly or non-conducting 4x6TM channel sensor proteins such as Nax or Cav 1.1. We propose that NALCN serves as a variable sensor that responds to calcium or sodium ion flux, depending on whether the total cellular current density is generated more from calcium-selective or sodium-selective channels.
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Affiliation(s)
- Adriano Senatore
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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Cardiac molecular-acclimation mechanisms in response to swimming-induced exercise in Atlantic salmon. PLoS One 2013; 8:e55056. [PMID: 23372811 PMCID: PMC3555865 DOI: 10.1371/journal.pone.0055056] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 12/19/2012] [Indexed: 12/05/2022] Open
Abstract
Cardiac muscle is a principal target organ for exercise-induced acclimation mechanisms in fish and mammals, given that sustained aerobic exercise training improves cardiac output. Yet, the molecular mechanisms underlying such cardiac acclimation have been scarcely investigated in teleosts. Consequently, we studied mechanisms related to cardiac growth, contractility, vascularization, energy metabolism and myokine production in Atlantic salmon pre-smolts resulting from 10 weeks exercise-training at three different swimming intensities: 0.32 (control), 0.65 (medium intensity) and 1.31 (high intensity) body lengths s−1. Cardiac responses were characterized using growth, immunofluorescence and qPCR analysis of a large number of target genes encoding proteins with significant and well-characterized function. The overall stimulatory effect of exercise on cardiac muscle was dependent on training intensity, with changes elicited by high intensity training being of greater magnitude than either medium intensity or control. Higher protein levels of PCNA were indicative of cardiac growth being driven by cardiomyocyte hyperplasia, while elevated cardiac mRNA levels of MEF2C, GATA4 and ACTA1 suggested cardiomyocyte hypertrophy. In addition, up-regulation of EC coupling-related genes suggested that exercised hearts may have improved contractile function, while higher mRNA levels of EPO and VEGF were suggestive of a more efficient oxygen supply network. Furthermore, higher mRNA levels of PPARα, PGC1α and CPT1 all suggested a higher capacity for lipid oxidation, which along with a significant enlargement of mitochondrial size in cardiac myocytes of the compact layer of fish exercised at high intensity, suggested an enhanced energetic support system. Training also elevated transcription of a set of myokines and other gene products related to the inflammatory process, such as TNFα, NFκB, COX2, IL1RA and TNF decoy receptor. This study provides the first characterization of the underlying molecular acclimation mechanisms in the heart of exercise-trained fish, which resemble those reported for mammalian physiological cardiac growth.
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Horstick EJ, Linsley JW, Dowling JJ, Hauser MA, McDonald KK, Ashley-Koch A, Saint-Amant L, Satish A, Cui WW, Zhou W, Sprague SM, Stamm DS, Powell CM, Speer MC, Franzini-Armstrong C, Hirata H, Kuwada JY. Stac3 is a component of the excitation-contraction coupling machinery and mutated in Native American myopathy. Nat Commun 2013; 4:1952. [PMID: 23736855 PMCID: PMC4056023 DOI: 10.1038/ncomms2952] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 04/30/2013] [Indexed: 11/09/2022] Open
Abstract
Excitation-contraction coupling, the process that regulates contractions by skeletal muscles, transduces changes in membrane voltage by activating release of Ca(2+) from internal stores to initiate muscle contraction. Defects in excitation-contraction coupling are associated with muscle diseases. Here we identify Stac3 as a novel component of the excitation-contraction coupling machinery. Using a zebrafish genetic screen, we generate a locomotor mutation that is mapped to stac3. We provide electrophysiological, Ca(2+) imaging, immunocytochemical and biochemical evidence that Stac3 participates in excitation-contraction coupling in muscles. Furthermore, we reveal that a mutation in human STAC3 is the genetic basis of the debilitating Native American myopathy (NAM). Analysis of NAM stac3 in zebrafish shows that the NAM mutation decreases excitation-contraction coupling. These findings enhance our understanding of both excitation-contraction coupling and the pathology of myopathies.
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Affiliation(s)
- Eric J. Horstick
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jeremy W. Linsley
- Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - James J. Dowling
- Department of Pediatrics, University of Michigan Medical Center, Ann Arbor, MI 48109, USA
| | - Michael A. Hauser
- Departments of Medicine and Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Kristin K. McDonald
- Departments of Medicine and Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Allison Ashley-Koch
- Departments of Medicine and Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Louis Saint-Amant
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Departement de Pathologie et Biologie Cellulaire, Universite de Montreal, Montreal, Canada H3T 1J4
| | - Akhila Satish
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Wilson W. Cui
- Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Weibin Zhou
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Life Science Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Shawn M. Sprague
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Demetra S. Stamm
- Department of Internal Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Cynthia M. Powell
- Departments of Pediatrics and Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Marcy C. Speer
- Center for Human Genetics, Duke University, Durham, NC 27710, USA
| | - Clara Franzini-Armstrong
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Hiromi Hirata
- National Institute of Genetics, Mishima 411-8540, Japan
| | - John Y. Kuwada
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
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Bannister RA, Beam KG. Ca(V)1.1: The atypical prototypical voltage-gated Ca²⁺ channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:1587-97. [PMID: 22982493 DOI: 10.1016/j.bbamem.2012.09.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 11/28/2022]
Abstract
Ca(V)1.1 is the prototype for the other nine known Ca(V) channel isoforms, yet it has functional properties that make it truly atypical of this group. Specifically, Ca(V)1.1 is expressed solely in skeletal muscle where it serves multiple purposes; it is the voltage sensor for excitation-contraction coupling and it is an L-type Ca²⁺ channel which contributes to a form of activity-dependent Ca²⁺ entry that has been termed Excitation-coupled Ca²⁺ entry. The ability of Ca(V)1.1 to serve as voltage-sensor for excitation-contraction coupling appears to be unique among Ca(V) channels, whereas the physiological role of its more conventional function as a Ca²⁺ channel has been a matter of uncertainty for nearly 50 years. In this chapter, we discuss how Ca(V)1.1 supports excitation-contraction coupling, the possible relevance of Ca²⁺ entry through Ca(V)1.1 and how alterations of Ca(V)1.1 function can have pathophysiological consequences. This article is part of a Special Issue entitled: Calcium channels.
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Affiliation(s)
- Roger A Bannister
- Department of Medicine, Cardiology Division, University of Colorado Denver-Anschutz Medical Campus, Aurora, CO 80045, USA.
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Ryanodine receptor calcium release channels: an evolutionary perspective. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:159-82. [PMID: 22453942 DOI: 10.1007/978-94-007-2888-2_7] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ryanodine receptors (RyRs), along with the related inositol 1,4,5-trisphosphate receptors (IP(3)Rs), mediate the release of Ca(2+) from intracellular organelles of eukaryotes. As discussed in other chapters, such increases in intracellular Ca(2+) levels act a fundamental second messenger, regulating a diverse array of cellular processes. For over two decades, it has been reported that vertebrates express multiple RYR genes, whereas non-vertebrate multicellular organisms possess a single homologue within their genomes. Recently, the existence of RyR-like channels in unicellular organisms has also been reported. This chapter exploits recent expansions in available genome data to generate an overview of the expression of RyR-like genes in organisms representing a broad range of viral, archaeal, bacterial and eukaryotic taxa. Analyses of the multidomain structures and phylogenetic relationships of these proteins has lead to a model in which, early during eukaryotic evolution, IP(3)R-like ancestral Ca(2+) release channels were converted to RyR proteins via the addition of promiscuous protein domains, possibly via horizontal gene transfer mechanisms.
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Ryanodine receptors, a family of intracellular calcium ion channels, are expressed throughout early vertebrate development. BMC Res Notes 2011; 4:541. [PMID: 22168922 PMCID: PMC3262159 DOI: 10.1186/1756-0500-4-541] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 12/14/2011] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Calcium signals ([Ca2+]i) direct many aspects of embryo development but their regulation is not well characterised. Ryanodine receptors (RyRs) are a family of intracellular Ca2+ release channels that control the flux of Ca2+ from internal stores into the cytosol. RyRs are primarily known for their role in excitation-contraction coupling in adult striated muscle and ryr gene mutations are implicated in several human diseases. Current evidence suggests that RyRs do not have a major role to play prior to organogenesis but regulate tissue differentiation. FINDINGS The sequences of the five zebrafish ryr genes were confirmed, their evolutionary relationship established and the primary sequences compared to other vertebrates, including humans. RyRs are differentially expressed in slow (ryr1a), fast (ryr3) and both types (ryr1b) of developing skeletal muscle. There are two ryr2 genes (ryr2a and ryr2b) which are expressed exclusively in developing CNS and cardiac tissue, respectively. In addition, ryr3 and ryr2a mRNA is detectable in the initial stages of development, prior to embryonic axis formation. CONCLUSIONS Our work reveals that zebrafish ryr genes are differentially expressed throughout the developing embryo from cleavage onwards. The data suggests that RyR-regulated Ca2+ signals are associated with several aspects of embryonic development, from organogenesis through to the differentiation of the musculoskeletal, cardiovascular and nervous system. These studies will facilitate further work to explore the developmental function of RyRs in each of these tissue types.
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Duran C, Qu Z, Osunkoya AO, Cui Y, Hartzell HC. ANOs 3-7 in the anoctamin/Tmem16 Cl- channel family are intracellular proteins. Am J Physiol Cell Physiol 2011; 302:C482-93. [PMID: 22075693 DOI: 10.1152/ajpcell.00140.2011] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca(2+)-activated Cl(-) channels (CaCCs) participate in numerous physiological functions such as neuronal excitability, sensory transduction, and transepithelial fluid transport. Recently, it was shown that heterologously expressed anoctamins ANO1 and ANO2 generate currents that resemble native CaCCs. The anoctamin family (also called Tmem16) consists of 10 members, but it is not known whether all members of the family are CaCCs. Expression of ANOs 3-7 in HEK293 cells did not generate Cl(-) currents activated by intracellular Ca(2+), as determined by whole cell patch clamp electrophysiology. With the use of confocal imaging, only ANO1 and ANO2 traffic to the plasma membrane when expressed heterologously. Furthermore, endogenously expressed ANO7 in the human prostate is predominantly intracellular. We took a chimeric approach to identify regions critical for channel trafficking and function. However, none of the chimeras of ANO1 and ANO5/7 that we made trafficked to the plasma membrane. Our results suggest that intracellular anoctamins may be endoplasmic reticulum proteins, although it remains unknown whether these family members are CaCCs. Determining the role of anoctamin family members in ion transport will be critical to understanding their functions in physiology and disease.
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Affiliation(s)
- Charity Duran
- Department of Cell Biology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, Georgia 30322-3030, USA
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Dayal A, Schredelseker J, Franzini-Armstrong C, Grabner M. Skeletal muscle excitation-contraction coupling is independent of a conserved heptad repeat motif in the C-terminus of the DHPRbeta(1a) subunit. Cell Calcium 2010; 47:500-6. [PMID: 20451250 PMCID: PMC2896708 DOI: 10.1016/j.ceca.2010.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 04/12/2010] [Accepted: 04/13/2010] [Indexed: 11/26/2022]
Abstract
In skeletal muscle excitation-contraction (EC) coupling the sarcolemmal L-type Ca(2+) channel or 1,4-dihydropyridine receptor (DHPR) transduces the membrane depolarization signal to the sarcoplasmic Ca(2+) release channel RyR1 via protein-protein interaction. While it is evident that the pore-forming and voltage-sensing DHPRalpha(1S) subunit is essential for this process, the intracellular DHPRbeta(1a) subunit was also shown to be indispensable. We previously found that the beta(1a) subunit is essential to target the DHPR into groups of four (tetrads) opposite the RyR1 homotetramers, a prerequisite for skeletal muscle EC coupling. Earlier, a unique hydrophobic heptad repeat motif (Lcdots, three dots, centeredVcdots, three dots, centeredV) in the C-terminus of beta(1a) was postulated by others to be essential for skeletal muscle EC coupling, as substitution of these residues with alanines resulted in 80% reduction of RyR1 Ca(2+) release. Therefore, we wanted to address the question if the proposed beta(1a) heptad repeat motif could be an active element of the DHPR-RyR1 signal transduction mechanism or already contributes at the ultrastructural level i.e. DHPR tetrad arrangement. Surprisingly, our experiments revealed full tetrad formation and an almost complete restoration of EC coupling in beta(1)-null zebrafish relaxed larvae and isolated myotubes upon expression of a beta(1a)-specific heptad repeat mutant (LVV to AAA) and thus contradict the earlier results.
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Affiliation(s)
- Anamika Dayal
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Austria
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