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A bridge from the endoplasmic reticulum to the plasma membrane comes into view. Proc Natl Acad Sci U S A 2022; 119:e2202254119. [PMID: 35353604 PMCID: PMC9169776 DOI: 10.1073/pnas.2202254119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Copola AGL, Dos Santos ÍGD, Coutinho LL, Del-Bem LEV, de Almeida Campos-Junior PH, da Conceição IMCA, Nogueira JM, do Carmo Costa A, Silva GAB, Jorge EC. Transcriptomic characterization of the molecular mechanisms induced by RGMa during skeletal muscle nuclei accretion and hypertrophy. BMC Genomics 2022; 23:188. [PMID: 35255809 PMCID: PMC8902710 DOI: 10.1186/s12864-022-08396-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 02/15/2022] [Indexed: 12/02/2022] Open
Abstract
Background The repulsive guidance molecule a (RGMa) is a GPI-anchor axon guidance molecule first found to play important roles during neuronal development. RGMa expression patterns and signaling pathways via Neogenin and/or as BMP coreceptors indicated that this axon guidance molecule could also be working in other processes and diseases, including during myogenesis. Previous works from our research group have consistently shown that RGMa is expressed in skeletal muscle cells and that its overexpression induces both nuclei accretion and hypertrophy in muscle cell lineages. However, the cellular components and molecular mechanisms induced by RGMa during the differentiation of skeletal muscle cells are poorly understood. In this work, the global transcription expression profile of RGMa-treated C2C12 myoblasts during the differentiation stage, obtained by RNA-seq, were reported. Results RGMa treatment could modulate the expression pattern of 2,195 transcripts in C2C12 skeletal muscle, with 943 upregulated and 1,252 downregulated. Among them, RGMa interfered with the expression of several RNA types, including categories related to the regulation of RNA splicing and degradation. The data also suggested that nuclei accretion induced by RGMa could be due to their capacity to induce the expression of transcripts related to ‘adherens junsctions’ and ‘extracellular-cell adhesion’, while RGMa effects on muscle hypertrophy might be due to (i) the activation of the mTOR-Akt independent axis and (ii) the regulation of the expression of transcripts related to atrophy. Finally, RGMa induced the expression of transcripts that encode skeletal muscle structural proteins, especially from sarcolemma and also those associated with striated muscle cell differentiation. Conclusions These results provide comprehensive knowledge of skeletal muscle transcript changes and pathways in response to RGMa. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08396-w.
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Affiliation(s)
- Aline Gonçalves Lio Copola
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31.270-901, Brasil
| | - Íria Gabriela Dias Dos Santos
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31.270-901, Brasil
| | - Luiz Lehmann Coutinho
- Departamento de Zootecnia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brasil
| | - Luiz Eduardo Vieira Del-Bem
- Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil
| | | | | | - Júlia Meireles Nogueira
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31.270-901, Brasil
| | - Alinne do Carmo Costa
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31.270-901, Brasil
| | - Gerluza Aparecida Borges Silva
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31.270-901, Brasil
| | - Erika Cristina Jorge
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av Antonio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais, 31.270-901, Brasil.
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Ashida Y, Himori K, Tamai K, Kimura I, Yamada T. Preconditioning contractions prevent prolonged force depression and Ca 2+-dependent proteolysis of STAC3 after damaging eccentric contractions. J Appl Physiol (1985) 2021; 131:1399-1407. [PMID: 34590910 DOI: 10.1152/japplphysiol.00463.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Preconditioning contractions (PCs) have been shown to markedly improve recovery from eccentric contractions (ECCs)-induced force depression. We here examined the mechanism behind the effects of PCs with focusing on the SH3 and cysteine-rich domain 3 (STAC3) that is essential for coupling membrane depolarization to Ca2+ release from the sarcoplasmic reticulum. Rat medial gastrocnemius (MG) muscles were excised immediately (REC0), 1 day (REC1), and 4 days (REC4) after exposure to 100 repeated damaging ECCs in vivo. PCs with 10 repeated nondamaging ECCs were applied 2 days before the damaging ECCs. Damaging ECCs induced in vivo isometric torque depression at 50 and 100 Hz stimulation frequencies, which was accompanied by a significant decrease in the amount of full-length STAC3, an activation of calpain 1, and an increased number of Evans Blue dye-positive fibers in MG muscles at REC1 and REC4. Interestingly, PCs attenuated all these deleterious alterations induced by damaging ECCs. Moreover, mechanistic experiments performed on normal muscle samples exposed to various concentration of Ca2+ showed a Ca2+-dependent proteolysis of STAC3, which was prevented by calpain inhibitor MDL-28170. In conclusion, PCs may improve recovery from force depression after damaging ECCs, in part by inhibiting the loss of STAC3 due to the increased permeability of cell membrane and subsequent activation of calpain 1.NEW & NOTEWORTHY The SH3 and cysteine-rich domain 3 (STAC3) is a skeletal muscle-specific protein that couples membrane depolarization to sarcoplasmic reticulum Ca2+ release. No studies, however, examined the role of STAC3 in protective effects of preconditioning contractions (PCs) against damaging eccentric contractions (ECCs). Here, we demonstrate that PCs may improve recovery from damaging ECCs-induced force depression, in part by an inhibition of Ca2+-dependent proteolysis of STAC3 due to increased membrane permeability and subsequent calpain 1 activation.
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Affiliation(s)
- Yuki Ashida
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan.,The Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Koichi Himori
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan.,The Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Katsuyuki Tamai
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Iori Kimura
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Takashi Yamada
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
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Shishmarev D. Excitation-contraction coupling in skeletal muscle: recent progress and unanswered questions. Biophys Rev 2020; 12:143-153. [PMID: 31950344 DOI: 10.1007/s12551-020-00610-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 01/03/2020] [Indexed: 02/07/2023] Open
Abstract
Excitation-contraction coupling (ECC) is a physiological process that links excitation of muscles by the nervous system to their mechanical contraction. In skeletal muscle, ECC is initiated with an action potential, generated by the somatic nervous system, which causes a depolarisation of the muscle fibre membrane (sarcolemma). This leads to a rapid change in the transmembrane potential, which is detected by the voltage-gated Ca2+ channel dihydropyridine receptor (DHPR) embedded in the sarcolemma. DHPR transmits the contractile signal to another Ca2+ channel, ryanodine receptor (RyR1), embedded in the membrane of the sarcoplasmic reticulum (SR), which releases a large amount of Ca2+ ions from the SR that initiate muscle contraction. Despite the fundamental role of ECC in skeletal muscle function of all vertebrate species, the molecular mechanism underpinning the communication between the two key proteins involved in the process (DHPR and RyR1) is still largely unknown. The goal of this work is to review the recent progress in our understanding of ECC in skeletal muscle from the point of view of the structure and interactions of proteins involved in the process, and to highlight the unanswered questions in the field.
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Affiliation(s)
- Dmitry Shishmarev
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
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5
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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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Son A, Park S, Shin DM, Muallem S. Orai1 and STIM1 in ER/PM junctions: roles in pancreatic cell function and dysfunction. Am J Physiol Cell Physiol 2016; 310:C414-22. [PMID: 26739495 DOI: 10.1152/ajpcell.00349.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Membrane contact sites (MCS) are critical junctions that form between the endoplasmic reticulum (ER) and membranes of various organelles, including the plasma membrane (PM). Signaling complexes, including mediators of Ca(2+) signaling, are assembled within MCS, such as the ER/PM junction. This is most evident in polarized epithelial cells, such as pancreatic cells. Core Ca(2+) signaling proteins cluster at the apical pole, the site of inositol 1,4,5-trisphosphate-mediated Ca(2+) release and Orai1/transient receptor potential canonical-mediated store-dependent Ca(2+) entry. Recent advances have characterized the proteins that tether the membranes at MCS and the role of these proteins in modulating physiological and pathological intracellular signaling. This review discusses recent advances in the characterization of Ca(2+) signaling at ER/PM junctions and the relation of these junctions to physiological and pathological Ca(2+) signaling in pancreatic acini.
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Affiliation(s)
- Aran Son
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Seonghee Park
- Department of Physiology, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland;
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Plomp JJ, Morsch M, Phillips WD, Verschuuren JJGM. Electrophysiological analysis of neuromuscular synaptic function in myasthenia gravis patients and animal models. Exp Neurol 2015; 270:41-54. [PMID: 25620417 DOI: 10.1016/j.expneurol.2015.01.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/07/2015] [Accepted: 01/16/2015] [Indexed: 12/21/2022]
Abstract
Study of the electrophysiological function of the neuromuscular junction (NMJ) is instrumental in the understanding of the symptoms and pathophysiology of myasthenia gravis (MG), an autoimmune disorder characterized by fluctuating and fatigable muscle weakness. Most patients have autoantibodies to the acetylcholine receptor at the NMJ. However, in recent years autoantibodies to other crucial postsynaptic membrane proteins have been found in previously 'seronegative' MG patients. Electromyographical recording of compound and single-fibre muscle action potentials provides a crucial in vivo method to determine neuromuscular transmission failure while ex vivo (miniature) endplate potential recordings can reveal the precise synaptic impairment. Here we will review these electrophysiological methods used to assess NMJ function and discuss their application and typical results found in the diagnostic and experimental study of patients and animal models of the several forms of MG.
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Affiliation(s)
- Jaap J Plomp
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands.
| | - Marco Morsch
- Motor Neuron Disease Research Group, Macquarie University, Sydney, Australia
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Prinz WA. Bridging the gap: membrane contact sites in signaling, metabolism, and organelle dynamics. ACTA ACUST UNITED AC 2014; 205:759-69. [PMID: 24958771 PMCID: PMC4068136 DOI: 10.1083/jcb.201401126] [Citation(s) in RCA: 296] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Regions of close apposition between two organelles, often referred to as membrane contact sites (MCSs), mostly form between the endoplasmic reticulum and a second organelle, although contacts between mitochondria and other organelles have also begun to be characterized. Although these contact sites have been noted since cells first began to be visualized with electron microscopy, the functions of most of these domains long remained unclear. The last few years have witnessed a dramatic increase in our understanding of MCSs, revealing the critical roles they play in intracellular signaling, metabolism, the trafficking of metabolites, and organelle inheritance, division, and transport.
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Affiliation(s)
- William A Prinz
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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Rebbeck RT, Karunasekara Y, Board PG, Beard NA, Casarotto MG, Dulhunty AF. Skeletal muscle excitation–contraction coupling: Who are the dancing partners? Int J Biochem Cell Biol 2014; 48:28-38. [DOI: 10.1016/j.biocel.2013.12.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/29/2013] [Accepted: 12/04/2013] [Indexed: 01/15/2023]
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Guerrero-Hernández A, Ávila G, Rueda A. Ryanodine receptors as leak channels. Eur J Pharmacol 2013; 739:26-38. [PMID: 24291096 DOI: 10.1016/j.ejphar.2013.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/21/2013] [Indexed: 01/18/2023]
Abstract
Ryanodine receptors are Ca(2+) release channels of internal stores. This review focuses on those situations and conditions that transform RyRs from a finely regulated ion channel to an unregulated Ca(2+) leak channel and the pathological consequences of this alteration. In skeletal muscle, mutations in either CaV1.1 channel or RyR1 results in a leaky behavior of the latter. In heart cells, RyR2 functions normally as a Ca(2+) leak channel during diastole within certain limits, the enhancement of this activity leads to arrhythmogenic situations that are tackled with different pharmacological strategies. In smooth muscle, RyRs are involved more in reducing excitability than in stimulating contraction so the leak activity of RyRs in the form of Ca(2+) sparks, locally activates Ca(2+)-dependent potassium channels to reduce excitability. In neurons the enhanced activity of RyRs is associated with the development of different neurodegenerative disorders such as Alzheimer and Huntington diseases. It appears then that the activity of RyRs as leak channels can have both physiological and pathological consequences depending on the cell type and the metabolic condition.
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Affiliation(s)
| | | | - Angélica Rueda
- Departamento de Bioquímica, Cinvestav, Mexico city, México
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11
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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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12
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Fontes-Oliveira CC, Busquets S, Fuster G, Ametller E, Figueras M, Olivan M, Toledo M, López-Soriano FJ, Qu X, Demuth J, Stevens P, Varbanov A, Wang F, Isfort RJ, Argilés JM. A differential pattern of gene expression in skeletal muscle of tumor-bearing rats reveals dysregulation of excitation-contraction coupling together with additional muscle alterations. Muscle Nerve 2013; 49:233-48. [DOI: 10.1002/mus.23893] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 04/19/2013] [Accepted: 04/24/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Cibely Cristine Fontes-Oliveira
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
| | - Sílvia Busquets
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
- Institut de Biomedicina de la Universitat de Barcelona; Barcelona Spain
| | - Gemma Fuster
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
| | - Elisabet Ametller
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
| | - Maite Figueras
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
| | - Mireia Olivan
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
| | - Míriam Toledo
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
| | - Francisco J. López-Soriano
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
- Institut de Biomedicina de la Universitat de Barcelona; Barcelona Spain
| | - Xiaoyan Qu
- Procter & Gamble; Mason Business Center; 8700 Mason-Montgomery Road Mason Ohio 45040 USA
| | - Jeffrey Demuth
- Procter & Gamble; Mason Business Center; 8700 Mason-Montgomery Road Mason Ohio 45040 USA
| | - Paula Stevens
- Procter & Gamble; Mason Business Center; 8700 Mason-Montgomery Road Mason Ohio 45040 USA
| | - Alex Varbanov
- Procter & Gamble; Mason Business Center; 8700 Mason-Montgomery Road Mason Ohio 45040 USA
| | - Feng Wang
- Procter & Gamble; Mason Business Center; 8700 Mason-Montgomery Road Mason Ohio 45040 USA
| | - Robert J. Isfort
- Procter & Gamble; Mason Business Center; 8700 Mason-Montgomery Road Mason Ohio 45040 USA
| | - Josep M. Argilés
- Cancer Research Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biologia; Universitat de Barcelona; Diagonal 643 Barcelona 08028 Spain
- Institut de Biomedicina de la Universitat de Barcelona; Barcelona Spain
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Helle SC, Kanfer G, Kolar K, Lang A, Michel AH, Kornmann B. Organization and function of membrane contact sites. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - MOLECULAR CELL RESEARCH 2013. [DOI: 10.1016.j.bbamcr.2013.01.02810.1016/j.bbamcr.2013.01.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Ca2+ channel and Na+/Ca2+ exchange localization in cardiac myocytes. J Mol Cell Cardiol 2013; 58:22-31. [DOI: 10.1016/j.yjmcc.2012.11.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 11/20/2012] [Accepted: 11/28/2012] [Indexed: 01/01/2023]
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15
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Helle SCJ, Kanfer G, Kolar K, Lang A, Michel AH, Kornmann B. Organization and function of membrane contact sites. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2526-41. [PMID: 23380708 DOI: 10.1016/j.bbamcr.2013.01.028] [Citation(s) in RCA: 323] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 01/18/2013] [Accepted: 01/21/2013] [Indexed: 11/16/2022]
Abstract
Membrane-bound organelles are a wonderful evolutionary acquisition of the eukaryotic cell, allowing the segregation of sometimes incompatible biochemical reactions into specific compartments with tailored microenvironments. On the flip side, these isolating membranes that crowd the interior of the cell, constitute a hindrance to the diffusion of metabolites and information to all corners of the cell. To ensure coordination of cellular activities, cells use a network of contact sites between the membranes of different organelles. These membrane contact sites (MCSs) are domains where two membranes come to close proximity, typically less than 30nm. Such contacts create microdomains that favor exchange between two organelles. MCSs are established and maintained in durable or transient states by tethering structures, which keep the two membranes in proximity, but fusion between the membranes does not take place. Since the endoplasmic reticulum (ER) is the most extensive cellular membrane network, it is thus not surprising to find the ER involved in most MCSs within the cell. The ER contacts diverse compartments such as mitochondria, lysosomes, lipid droplets, the Golgi apparatus, endosomes and the plasma membrane. In this review, we will focus on the common organizing principles underlying the many MCSs found between the ER and virtually all compartments of the cell, and on how the ER establishes a network of MCSs for the trafficking of vital metabolites and information. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
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Affiliation(s)
- Sebastian C J Helle
- Institute of Biochemistry, ETH Zürich, HPM G16 Schafmattstrasse, Zürich, Switzerland
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16
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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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17
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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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18
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Karunasekara Y, Rebbeck RT, Weaver LM, Board PG, Dulhunty AF, Casarotto MG. An α-helical C-terminal tail segment of the skeletal L-type Ca2+ channel β1a subunit activates ryanodine receptor type 1 via a hydrophobic surface. FASEB J 2012; 26:5049-59. [PMID: 22962299 DOI: 10.1096/fj.12-211334] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Excitation-contraction (EC) coupling in skeletal muscle depends on protein interactions between the transverse tubule dihydropyridine receptor (DHPR) voltage sensor and intracellular ryanodine receptor (RyR1) calcium release channel. We present novel data showing that the C-terminal 35 residues of the β(1a) subunit adopt a nascent α-helix in which 3 hydrophobic residues align to form a hydrophobic surface that binds to RyR1 isolated from rabbit skeletal muscle. Mutation of the hydrophobic residues (L496, L500, W503) in peptide β(1a)V490-M524, corresponding to the C-terminal 35 residues of β(1a), reduced peptide binding to RyR1 to 15.2 ± 7.1% and prevented the 2.9 ± 0.2-fold activation of RyR1 by 10 nM wild-type peptide. An upstream hydrophobic heptad repeat implicated in β(1a) binding to RyR1 does not contribute to RyR1 activation. Wild-type β(1a)A474-A508 peptide (10 nM), containing heptad repeat and hydrophobic surface residues, increased RyR1 activity by 2.3 ± 0.2- and 2.2 ± 0.3-fold after mutation of the heptad repeat residues. We conclude that specific hydrophobic surface residues in the 35 residue β(1a) C-terminus bind to RyR1 and increase channel activity in lipid bilayers and thus may support skeletal EC coupling.
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Affiliation(s)
- Yamuna Karunasekara
- Department of Translational Bioscience, John Curtin School of Medical Research, Australian National University, P.O. Box 334, Canberra, ACT 2601, Australia
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19
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Huang CLH, Pedersen TH, Fraser JA. Reciprocal dihydropyridine and ryanodine receptor interactions in skeletal muscle activation. J Muscle Res Cell Motil 2011; 32:171-202. [PMID: 21993921 DOI: 10.1007/s10974-011-9262-9] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2011] [Accepted: 09/12/2011] [Indexed: 11/25/2022]
Abstract
Dihydropyridine (DHPR) and ryanodine receptors (RyRs) are central to transduction of transverse (T) tubular membrane depolarisation initiated by surface action potentials into release of sarcoplasmic reticular (SR) Ca2+ in skeletal muscle excitation-contraction coupling. Electronmicroscopic methods demonstrate an orderly positioning of such tubular DHPRs relative to RyRs in the SR at triad junctions where their membranes come into close proximity. Biochemical and genetic studies associated expression of specific, DHPR and RyR, isoforms with the particular excitation-contraction coupling processes and related elementary Ca2+ release events found respectively in skeletal and cardiac muscle. Physiological studies of intramembrane charge movements potentially related to voltage triggering of Ca2+ release demonstrated a particular qγ charging species identifiable with DHPRs through its T-tubular localization, pharmacological properties, and steep voltage-dependence paralleling Ca2+ release. Its nonlinear kinetics implicated highly co-operative conformational events in its transitions in response to voltage change. The effects of DHPR and RyR agonists and antagonists upon this intramembrane charge in turn implicated reciprocal rather than merely unidirectional DHPR-RyR interactions in these complex reactions. Thus, following membrane potential depolarization, an orthograde qγ-DHPR-RyR signaling likely initiates conformational alterations in the RyR with which it makes contact. The latter changes could then retrogradely promote further qγ-DHPR transitions through reciprocal co-operative allosteric interactions between receptors. These would relieve the resting constraints on both further, delayed, nonlinear qγ-DHPR charge transfers and on RyR-mediated Ca2+ release. They would also explain the more rapid charging and recovery qγ transients following larger depolarizations and membrane potential repolarization to the resting level.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory, Department of Biochemistry, University of Cambridge, Cambridge, CB2 3EG, UK.
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20
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Capiod T. Cell proliferation, calcium influx and calcium channels. Biochimie 2011; 93:2075-9. [PMID: 21802482 DOI: 10.1016/j.biochi.2011.07.015] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 07/12/2011] [Indexed: 01/14/2023]
Abstract
Both increases in the basal cytosolic calcium concentration ([Ca(2+)](cyt)) and [Ca(2+)](cyt) transients play major roles in cell cycle progression, cell proliferation and division. Calcium transients are observed at various stages of cell cycle and more specifically during late G(1) phase, before and during mitosis. These calcium transients are mainly due to calcium release and reuptake by the endoplasmic reticulum (ER) and are observed over periods of hours in oocytes and mammalian cells. Calcium entry sustains the ER Ca(2+) load and thereby helps to maintain these calcium transients for such a long period. Calcium influx also controls cell growth and proliferation in several cell types. Various calcium channels are involved in this process and the tight relation between the expression and activity of cyclins and calcium channels also suggests that calcium entry may be needed only at particular stages of the cell cycle. Consistent with this idea, the expression of l-type and T-type calcium channels and SOCE amplitude fluctuate along the cell cycle. But, as calcium influx regulates several other transduction pathways, the presence of a specific connection to trigger activation of proliferation and cell division in mammalian cells will be discussed in this review.
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Affiliation(s)
- Thierry Capiod
- INSERM U807, Faculté de Médecine, 156 rue de Vaugirard, Paris, France.
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21
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Rebbeck RT, Karunasekara Y, Gallant EM, Board PG, Beard NA, Casarotto MG, Dulhunty AF. The β(1a) subunit of the skeletal DHPR binds to skeletal RyR1 and activates the channel via its 35-residue C-terminal tail. Biophys J 2011; 100:922-30. [PMID: 21320436 DOI: 10.1016/j.bpj.2011.01.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 12/30/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022] Open
Abstract
Although it has been suggested that the C-terminal tail of the β(1a) subunit of the skeletal dihyropyridine receptor (DHPR) may contribute to voltage-activated Ca(2+) release in skeletal muscle by interacting with the skeletal ryanodine receptor (RyR1), a direct functional interaction between the two proteins has not been demonstrated previously. Such an interaction is reported here. A peptide with the sequence of the C-terminal 35 residues of β(1a) bound to RyR1 in affinity chromatography. The full-length β(1a) subunit and the C-terminal peptide increased [(3)H]ryanodine binding and RyR1 channel activity with an AC(50) of 450-600 pM under optimal conditions. The effect of the peptide was dependent on cytoplasmic Ca(2+), ATP, and Mg(2+) concentrations. There was no effect of the peptide when channel activity was very low as a result of Mg(2+) inhibition or addition of 100 nM Ca(2+) (without ATP). Maximum increases were seen with 1-10 μM Ca(2+), in the absence of Mg(2+) inhibition. A control peptide with the C-terminal 35 residues in a scrambled sequence did not bind to RyR1 or alter [(3)H]ryanodine binding or channel activity. This high-affinity in vitro functional interaction between the C-terminal 35 residues of the DHPR β(1a) subunit and RyR1 may support an in vivo function of β(1a) during voltage-activated Ca(2+) release.
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Affiliation(s)
- Robyn T Rebbeck
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
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22
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Affiliation(s)
- Kurt G Beam
- Department of Physiology and Biophysics, School of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO 80045, USA.
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23
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Couchoux H, Bichraoui H, Chouabe C, Altafaj X, Bonvallet R, Allard B, Ronjat M, Berthier C. Caveolin-3 is a direct molecular partner of the Cav1.1 subunit of the skeletal muscle L-type calcium channel. Int J Biochem Cell Biol 2011; 43:713-20. [PMID: 21262376 DOI: 10.1016/j.biocel.2011.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 12/18/2010] [Accepted: 01/17/2011] [Indexed: 12/14/2022]
Abstract
Caveolin-3 is the striated muscle specific isoform of the scaffolding protein family of caveolins and has been shown to interact with a variety of proteins, including ion channels. Mutations in the human CAV3 gene have been associated with several muscle disorders called caveolinopathies and among these, the P104L mutation (Cav-3(P104L)) leads to limb girdle muscular dystrophy of type 1C characterized by the loss of sarcolemmal caveolin. There is still no clear-cut explanation as to specifically how caveolin-3 mutations lead to skeletal muscle wasting. Previous results argued in favor of a role for caveolin-3 in dihydropyridine receptor (DHPR) functional regulation and/or T-tubular membrane localization. It appeared worth closely examining such a functional link and investigating if it could result from the direct physical interaction of the two proteins. Transient expression of Cav-3(P104L) or caveolin-3 specific siRNAs in C2C12 myotubes both led to a significant decrease of the L-type Ca(2+) channel maximal conductance. Immunolabeling analysis of adult skeletal muscle fibers revealed the colocalization of a pool of caveolin-3 with the DHPR within the T-tubular membrane. Caveolin-3 was also shown to be present in DHPR-containing triadic membrane preparations from which both proteins co-immunoprecipitated. Using GST-fusion proteins, the I-II loop of Ca(v)1.1 was identified as the domain interacting with caveolin-3, with an apparent affinity of 60nM. The present study thus revealed a direct molecular interaction between caveolin-3 and the DHPR which is likely to underlie their functional link and whose loss might therefore be involved in pathophysiological mechanisms associated to muscle caveolinopathies.
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Affiliation(s)
- Harold Couchoux
- Physiologie Intégrative Cellulaire et Moléculaire, Université Lyon 1, UMR CNRS 5123, Université de Lyon, 43 Boulevard du 11 novembre 1918, F-69622 Villeurbanne, France
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24
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Excitation-contraction coupling and minor triadic proteins in low-frequency fatigue. Exerc Sport Sci Rev 2010; 38:135-42. [PMID: 20577062 DOI: 10.1097/jes.0b013e3181e3734d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Low-frequency fatigue (LFF) is characterized by a proportionally greater loss of force at low compared with high activation frequencies and a prolonged recovery. Recent work suggests a calcium-induced uncoupling of excitation-contraction coupling underlies LFF. Here, newly characterized triadic proteins are described, and possible mechanisms by which they may contribute to LFF are suggested.
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25
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Weiss N, Legrand C, Pouvreau S, Bichraoui H, Allard B, Zamponi GW, De Waard M, Jacquemond V. In vivo expression of G-protein beta1gamma2 dimer in adult mouse skeletal muscle alters L-type calcium current and excitation-contraction coupling. J Physiol 2010; 588:2945-60. [PMID: 20547679 DOI: 10.1113/jphysiol.2010.191593] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A number of G-protein-coupled receptors are expressed in skeletal muscle but their roles in muscle physiology and downstream effector systems remain poorly investigated. Here we explored the functional importance of the G-protein betagamma (Gbetagamma) signalling pathway on voltage-controlled Ca(2+) homeostasis in single isolated adult skeletal muscle fibres. A GFP-tagged Gbeta(1)gamma(2) dimer was expressed in vivo in mice muscle fibres. The GFP fluorescence pattern was consistent with a Gbeta(1)gamma(2) dimer localization in the transverse-tubule membrane. Membrane current and indo-1 fluorescence measurements performed under voltage-clamp conditions reveal a drastic reduction of both L-type Ca(2+) current density and of peak amplitude of the voltage-activated Ca(2+) transient in Gbeta(1)gamma(2)-expressing fibres. These effects were not observed upon expression of Gbeta(2)gamma(2), Gbeta(3)gamma(2) or Gbeta(4)gamma(2). Our data suggest that the G-protein beta(1)gamma(2) dimer may play an important regulatory role in skeletal muscle excitation-contraction coupling.
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Affiliation(s)
- Norbert Weiss
- Université Lyon 1, UMR CNRS 5123, Physiologie Intégrative Cellulaire et Moléculaire, Bâtiment R. Dubois, 43 boulevard du 11 novembre 1918, Villeurbanne, France.
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26
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Friedrich O, Fink RHA, von Wegner F. New factors contributing to dynamic calcium regulation in the skeletal muscle triad-a crowded place. Biophys Rev 2010; 2:29-38. [PMID: 28509943 PMCID: PMC5425672 DOI: 10.1007/s12551-009-0027-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 11/20/2009] [Indexed: 10/20/2022] Open
Abstract
Skeletal muscle is a highly organized tissue that has to be optimized for fast signalling events conveying electrical excitation to contractile response. The site of electro-chemico-mechanical coupling is the skeletal muscle triad where two membrane systems, the extracellular t-tubules and the intracellular sarcoplasmic reticulum, come into very close contact. Structure fits function here and the signalling proteins DHPR and RyR1 were the first to be discovered to bridge this gap in a conformational coupling arrangement. Since then, however, new proteins and more signalling cascades have been identified just in the last decade, adding more diversity and fine tuning to the regulation of excitation-contraction coupling (ECC) and control over Ca2+ store content. The concept of Ca2+ entry into working skeletal muscle has become attractive again with the experimental evidence summarized in this review. Store-operated Ca2+ entry (SOCE), excitation-coupled Ca2+ entry (ECCE), action-potential-activated Ca2+ current (APACC), and retrograde EC-coupling (ECC) are new concepts additional to the conventional orthograde ECC; they have provided fascinating new insights into muscle physiology. In this review, we discuss the discovery of these pathways, their potential roles, and the signalling proteins involved that show that the triad may become a crowded place in time.
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Affiliation(s)
- Oliver Friedrich
- Medical Biophysics, Institute of Physiology & Pathophysiology, University of Heidelberg, INF 326, 69120, Heidelberg, Germany
- School of Biomedical Sciences, University of Queensland, St. Lucia, 4072, Brisbane, QLD, Australia
| | - Rainer H A Fink
- Medical Biophysics, Institute of Physiology & Pathophysiology, University of Heidelberg, INF 326, 69120, Heidelberg, Germany
| | - Frederic von Wegner
- Medical Biophysics, Institute of Physiology & Pathophysiology, University of Heidelberg, INF 326, 69120, Heidelberg, Germany.
- Brain Imaging Center, Goethe University, Schleusenweg 2-16, 60528, Frankfurt a.M., Germany.
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27
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Corona BT, Balog EM, Doyle JA, Rupp JC, Luke RC, Ingalls CP. Junctophilin damage contributes to early strength deficits and EC coupling failure after eccentric contractions. Am J Physiol Cell Physiol 2009; 298:C365-76. [PMID: 19940065 DOI: 10.1152/ajpcell.00365.2009] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Junctophilins (JP1 and JP2) are expressed in skeletal muscle and are the primary proteins involved in transverse (T)-tubule and sarcoplasmic reticulum (SR) membrane apposition. During the performance of eccentric contractions, the apposition of T-tubule and SR membranes may be disrupted, resulting in excitation-contraction (EC) coupling failure and thus reduced force-producing capacity. In this study, we made three primary observations: 1) through the first 3 days after the performance of 50 eccentric contractions in vivo by the left hindlimb anterior crural muscles of female mice, both JP1 and JP2 were significantly reduced by approximately 50% and 35%, respectively, while no reductions were observed after the performance of nonfatiguing concentric contractions; 2) following the performance of a repeated bout of 50 eccentric contractions in vivo, only JP1 was immediately reduced ( approximately 30%) but recovered by 3-day postinjury in tandem with the recovery of strength and EC coupling; and 3) following the performance of 10 eccentric contractions at either 15 degrees or 35 degrees C by isolated mouse extensor digitorum longus (EDL) muscle, isometric force, EC coupling, and JP1 and JP2 were only reduced after the eccentric contractions performed at 35 degrees C. Regression analysis of JP1 and JP2 content in tibialis anterior and EDL muscles from each set of experiments indicated that JP damage is significantly associated with early (0-3 days) strength deficits after performance of eccentric contractions (R = 0.49; P < 0.001). As a whole, the results of this study indicate that JP damage plays a role in early force deficits due to EC coupling failure following the performance of eccentric contractions.
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Affiliation(s)
- B T Corona
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia, USA
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28
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von Wegner F, Schurmann S, Fink RHA, Vogel M, Friedrich O. Motor protein function in skeletal muscle-a multiple scale approach to contractility. IEEE TRANSACTIONS ON MEDICAL IMAGING 2009; 28:1632-1642. [PMID: 19574163 DOI: 10.1109/tmi.2009.2026171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present an approach to skeletal muscle contractility and its regulation over different scales ranging from biomechanical studies in intact muscle fibers down to the motility and interaction of single motor protein molecules. At each scale, shortening velocities as a measure for weak cross-bridge cycling rates are extracted and compared. Experimental approaches include transmitted light microscopy, second harmonic generation imaging of contracting myofibrils, and fluorescence microscopy of single molecule motility. Each method yields image sequences that are analyzed with automated image processing algorithms to extract the contraction velocity. Using this approach, we show how to isolate the contribution of the motor proteins actin and myosin and their modulation by regulatory proteins from the concerted action of electro-mechanical activation on a more complex cellular scale. The advantage of this approach is that averaged contraction velocities can be determined on the different scales ranging from isolated motor proteins to sarcomere levels in myofibrils and myofibril arrays within the cellular architecture. Our results show that maximum shortening velocities during in situ electrical activation of sarcomere contraction in intact single muscle cells can substantially deviate from sliding velocities obtained in oriented in vitro motility assays of isolated motor proteins showing that biophysical contraction kinetics not simply translate linearly between contractility scales. To adequately resolve the very fast initial mechanical activation kinetics of shortening at each scale, it was necessary to implement high-speed imaging techniques. In the case of intact fibers and single molecule motility, we achieved a major increase in temporal resolution up to frame rates of 200-1000 fps using CMOS image sensor technology. The data we obtained at this unprecedented temporal resolution and the parameters extracted can be used to validate results obtained from computational models of motor protein interaction and skeletal muscle contractility in health and muscle disease. Our approach is feasible to explain the possible underlying mechanisms that contribute to different shortening velocities at different scales and complexities.
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Affiliation(s)
- Frederic von Wegner
- Medical Biophysics Group, Institute of Physiology, University of Heidelberg, 69120 Heidelberg, Germany.
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29
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Levy S, Beharier O, Etzion Y, Mor M, Buzaglo L, Shaltiel L, Gheber LA, Kahn J, Muslin AJ, Katz A, Gitler D, Moran A. Molecular basis for zinc transporter 1 action as an endogenous inhibitor of L-type calcium channels. J Biol Chem 2009; 284:32434-43. [PMID: 19767393 DOI: 10.1074/jbc.m109.058842] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The L-type calcium channel (LTCC) has a variety of physiological roles that are critical for the proper function of many cell types and organs. Recently, a member of the zinc-regulating family of proteins, ZnT-1, was recognized as an endogenous inhibitor of the LTCC, but its mechanism of action has not been elucidated. In the present study, using two-electrode voltage clamp recordings in Xenopus oocytes, we demonstrate that ZnT-1-mediated inhibition of the LTCC critically depends on the presence of the LTCC regulatory beta-subunit. Moreover, the ZnT-1-induced inhibition of the LTCC current is also abolished by excess levels of the beta-subunit. An interaction between ZnT-1 and the beta-subunit, as demonstrated by co-immunoprecipitation and by fluorescence resonance energy transfer, is consistent with this result. Using surface biotinylation and total internal reflection fluorescence microscopy in HEK293 cells, we show a ZnT-1-dependent decrease in the surface expression of the pore-forming alpha(1)-subunit of the LTCC. Similarly, a decrease in the surface expression of the alpha(1)-subunit is observed following up-regulation of the expression of endogenous ZnT-1 in rapidly paced cultured cardiomyocytes. We conclude that ZnT-1-mediated inhibition of the LTCC is mediated through a functional interaction of ZnT-1 with the LTCC beta-subunit and that it involves a decrease in the trafficking of the LTCC alpha(1)-subunit to the surface membrane.
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Affiliation(s)
- Shiri Levy
- Department of Physiology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84101, Israel
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30
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Bannister RA, Papadopoulos S, Haarmann CS, Beam KG. Effects of inserting fluorescent proteins into the alpha1S II-III loop: insights into excitation-contraction coupling. ACTA ACUST UNITED AC 2009; 134:35-51. [PMID: 19564426 PMCID: PMC2712974 DOI: 10.1085/jgp.200910241] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In skeletal muscle, intermolecular communication between the 1,4-dihydropyridine receptor (DHPR) and RYR1 is bidirectional: orthograde coupling (skeletal excitation-contraction coupling) is observed as depolarization-induced Ca(2+) release via RYR1, and retrograde coupling is manifested by increased L-type Ca(2+) current via DHPR. A critical domain (residues 720-765) of the DHPR alpha(1S) II-III loop plays an important but poorly understood role in bidirectional coupling with RYR1. In this study, we examine the consequences of fluorescent protein insertion into different positions within the alpha(1S) II-III loop. In four constructs, a cyan fluorescent protein (CFP)-yellow fluorescent protein (YFP) tandem was introduced in place of residues 672-685 (the peptide A region). All four constructs supported efficient bidirectional coupling as determined by the measurement of L-type current and myoplasmic Ca(2+) transients. In contrast, insertion of a CFP-YFP tandem within the N-terminal portion of the critical domain (between residues 726 and 727) abolished bidirectional signaling. Bidirectional coupling was partially preserved when only a single YFP was inserted between residues 726 and 727. However, insertion of YFP near the C-terminal boundary of the critical domain (between residues 760 and 761) or in the conserved C-terminal portion of the alpha(1S) II-III loop (between residues 785 and 786) eliminated bidirectional coupling. None of the fluorescent protein insertions, even those that interfered with signaling, significantly altered membrane expression or targeting. Thus, bidirectional signaling is ablated by insertions at two different sites in the C-terminal portion of the alpha(1S) II-III loop. Significantly, our results indicate that the conserved portion of the alpha(1S) II-III loop C terminal to the critical domain plays an important role in bidirectional coupling either by conveying conformational changes to the critical domain from other regions of the DHPR or by serving as a site of interaction with other junctional proteins such as RYR1.
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Affiliation(s)
- Roger A Bannister
- Department of Physiology and Biophysics, School of Medicine, University of Colorado Denver, Aurora, CO 80045, USA
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31
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Bannister RA, Grabner M, Beam KG. The alpha(1S) III-IV loop influences 1,4-dihydropyridine receptor gating but is not directly involved in excitation-contraction coupling interactions with the type 1 ryanodine receptor. J Biol Chem 2008; 283:23217-23. [PMID: 18556650 PMCID: PMC2516988 DOI: 10.1074/jbc.m804312200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 06/13/2008] [Indexed: 11/06/2022] Open
Abstract
In skeletal muscle, coupling between the 1,4-dihydropyridine receptor (DHPR) and the type 1 ryanodine receptor (RyR1) underlies excitation-contraction (EC) coupling. The III-IV loop of the DHPR alpha(1S) subunit binds to a segment of RyR1 in vitro, and mutations in the III-IV loop alter the voltage dependence of EC coupling, raising the possibility that this loop is directly involved in signal transmission from the DHPR to RyR1. To clarify the role of the alpha(1S) III-IV loop in EC coupling, we examined the functional properties of a chimera (GFP-alpha(1S)[III-IVa]) in which the III-IV loop of the divergent alpha(1A) isoform replaced that of alpha(1S). Dysgenic myotubes expressing GFP-alpha(1S)[III-IVa] yielded myoplasmic Ca(2+) transients that activated at approximately 10 mV more hyperpolarized potentials and that were approximately 65% smaller than those of GFP-alpha(1S). A similar reduction was observed in voltage-dependent charge movements for GFP-alpha(1S)[III-IVa], indicating that the chimeric channels trafficked less well to the membrane but that those that were in the membrane functioned as efficiently in EC coupling as GFP-alpha(1S). Relative to GFP-alpha(1S), L-type currents mediated by GFP-alpha(1S)[III-IVa] were approximately 40% smaller and activated at approximately 5 mV more hyperpolarized potentials. The altered gating of GFP-alpha(1S)[III-IVa] was accentuated by exposure to +/-Bay K 8644, which caused a much larger hyperpolarizing shift in activation compared with its effect on GFP-alpha(1S). Taken together, our observations indicate that the alpha(1S) III-IV loop is not directly involved in EC coupling but does influence DHPR gating transitions important both for EC coupling and activation of L-type conductance.
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Affiliation(s)
- Roger A Bannister
- Department of Physiology and Biophysics, University of Colorado-Denver, Aurora, Colorado 80045, USA
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