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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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2
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Feng W, Lopez JR, Antrobus S, Zheng J, Uryash A, Dong Y, Beqollari D, Bannister RA, Hopkins PM, Beam KG, Allen PD, Pessah IN. Putative malignant hyperthermia mutation Ca V1.1-R174W is insufficient to trigger a fulminant response to halothane or confer heat stress intolerance. J Biol Chem 2023; 299:104992. [PMID: 37392848 PMCID: PMC10413282 DOI: 10.1016/j.jbc.2023.104992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/03/2023] Open
Abstract
Malignant hyperthermia susceptibility (MHS) is an autosomal dominant pharmacogenetic disorder that manifests as a hypermetabolic state when carriers are exposed to halogenated volatile anesthetics or depolarizing muscle relaxants. In animals, heat stress intolerance is also observed. MHS is linked to over 40 variants in RYR1 that are classified as pathogenic for diagnostic purposes. More recently, a few rare variants linked to the MHS phenotype have been reported in CACNA1S, which encodes the voltage-activated Ca2+ channel CaV1.1 that conformationally couples to RyR1 in skeletal muscle. Here, we describe a knock-in mouse line that expresses one of these putative variants, CaV1.1-R174W. Heterozygous (HET) and homozygous (HOM) CaV1.1-R174W mice survive to adulthood without overt phenotype but fail to trigger with fulminant malignant hyperthermia when exposed to halothane or moderate heat stress. All three genotypes (WT, HET, and HOM) express similar levels of CaV1.1 by quantitative PCR, Western blot, [3H]PN200-110 receptor binding and immobilization-resistant charge movement densities in flexor digitorum brevis fibers. Although HOM fibers have negligible CaV1.1 current amplitudes, HET fibers have similar amplitudes to WT, suggesting a preferential accumulation of the CaV1.1-WT protein at triad junctions in HET animals. Never-the-less both HET and HOM have slightly elevated resting free Ca2+ and Na+ measured with double barreled microelectrode in vastus lateralis that is disproportional to upregulation of transient receptor potential canonical (TRPC) 3 and TRPC6 in skeletal muscle. CaV1.1-R174W and upregulation of TRPC3/6 alone are insufficient to trigger fulminant malignant hyperthermia response to halothane and/or heat stress in HET and HOM mice.
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Affiliation(s)
- Wei Feng
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Jose R Lopez
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA; Department of Research, Mount Sinai Medical Center, Miami Beach, Florida, USA
| | - Shane Antrobus
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Jing Zheng
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Arkady Uryash
- Department of Research, Mount Sinai Medical Center, Miami Beach, Florida, USA
| | - Yao Dong
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Donald Beqollari
- Department of Medicine-Cardiology Division, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Roger A Bannister
- Department of Medicine-Cardiology Division, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Philip M Hopkins
- Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom
| | - Kurt G Beam
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Paul D Allen
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA; Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom
| | - Isaac N Pessah
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA.
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3
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Rossi D, Catallo MR, Pierantozzi E, Sorrentino V. Mutations in proteins involved in E-C coupling and SOCE and congenital myopathies. J Gen Physiol 2022; 154:e202213115. [PMID: 35980353 PMCID: PMC9391951 DOI: 10.1085/jgp.202213115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/15/2022] [Accepted: 07/21/2022] [Indexed: 11/24/2022] Open
Abstract
In skeletal muscle, Ca2+ necessary for muscle contraction is stored and released from the sarcoplasmic reticulum (SR), a specialized form of endoplasmic reticulum through the mechanism known as excitation-contraction (E-C) coupling. Following activation of skeletal muscle contraction by the E-C coupling mechanism, replenishment of intracellular stores requires reuptake of cytosolic Ca2+ into the SR by the activity of SR Ca2+-ATPases, but also Ca2+ entry from the extracellular space, through a mechanism called store-operated calcium entry (SOCE). The fine orchestration of these processes requires several proteins, including Ca2+ channels, Ca2+ sensors, and Ca2+ buffers, as well as the active involvement of mitochondria. Mutations in genes coding for proteins participating in E-C coupling and SOCE are causative of several myopathies characterized by a wide spectrum of clinical phenotypes, a variety of histological features, and alterations in intracellular Ca2+ balance. This review summarizes current knowledge on these myopathies and discusses available knowledge on the pathogenic mechanisms of disease.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Maria Rosaria Catallo
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
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4
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Aleman M, Zhang R, Feng W, Qi L, Lopez JR, Crowe C, Dong Y, Cherednichenko G, Pessah IN. Dietary Caffeine Synergizes Adverse Peripheral and Central Responses to Anesthesia in Malignant Hyperthermia Susceptible Mice. Mol Pharmacol 2020; 98:351-363. [PMID: 32764093 DOI: 10.1124/mol.120.119412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/31/2020] [Indexed: 11/22/2022] Open
Abstract
Ryanodine receptor (RYR) mutations confer stress-triggered malignant hyperthermia (MH) susceptibility. Dietary caffeine (CAF) is the most commonly consumed psychoactive compound by humans. CAF-triggered Ca2+ release and its influences on skeletal muscle contractility are widely used as experimental tools to study RYR function/dysfunction and diagnose MH susceptibility. We hypothesize that dietary CAF achieving blood levels measured in human plasma exacerbates the penetrance of RYR1 MH susceptibility mutations triggered by gaseous anesthetic, affecting both central and peripheral adverse responses. Heterozygous R163C-RYR1 (HET) MH susceptible mice are used to investigate the influences of dietary CAF on both peripheral and central responses before and after induction of halothane (HAL) maintenance anesthesia under experimental conditions that maintain normal core body temperature. HET mice receiving CAF (plasma CAF 893 ng/ml) have significantly shorter times to respiratory arrest compared with wild type, without altering blood chemistry or displaying hyperthermia or muscle rigor. Intraperitoneal bolus dantrolene before HAL prolongs time to respiratory arrest. A pilot electrographic study using subcutaneous electrodes reveals that dietary CAF does not alter baseline electroencephalogram (EEG) total power, but significantly shortens delay to isoelectric EEG, which precedes respiratory and cardiac arrest. CAF ± HAL are studied on RYR1 single-channel currents and HET myotubes to define molecular mechanisms of gene-by-environment synergism. Strong pharmacological synergism between CAF and HAL is demonstrated in both single-channel and myotube preparations. Central and peripheral nervous systems mediate adverse responses to HAL in a HET model of MH susceptibility exposed to dietary CAF, a modifiable lifestyle factor that may mitigate risks of acute and chronic diseases associated with RYR1 mutations. SIGNIFICANCE STATEMENT: Dietary caffeine at a human-relevant dose synergizes adverse peripheral and central responses to anesthesia in malignant hyperthermia susceptible mice. Synergism of these drugs can be attributed to their actions at ryanodine receptors.
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Affiliation(s)
- Monica Aleman
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Rui Zhang
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Wei Feng
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Lihong Qi
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Jose R Lopez
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Chelsea Crowe
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Yao Dong
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Genady Cherednichenko
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
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5
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Iyer KA, Hu Y, Nayak AR, Kurebayashi N, Murayama T, Samsó M. Structural mechanism of two gain-of-function cardiac and skeletal RyR mutations at an equivalent site by cryo-EM. SCIENCE ADVANCES 2020; 6:eabb2964. [PMID: 32832689 PMCID: PMC7439390 DOI: 10.1126/sciadv.abb2964] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/10/2020] [Indexed: 05/16/2023]
Abstract
Mutations in ryanodine receptors (RyRs), intracellular Ca2+ channels, are associated with deadly disorders. Despite abundant functional studies, the molecular mechanism of RyR malfunction remains elusive. We studied two single-point mutations at an equivalent site in the skeletal (RyR1 R164C) and cardiac (RyR2 R176Q) isoforms using ryanodine binding, Ca2+ imaging, and cryo-electron microscopy (cryo-EM) of the full-length protein. Loss of the positive charge had greater effect on the skeletal isoform, mediated via distortion of a salt bridge network, a molecular latch inducing rotation of a cytoplasmic domain, and partial progression to open-state traits of the large cytoplasmic assembly accompanied by alteration of the Ca2+ binding site, which concur with the major "hyperactive" feature of the mutated channel. Our cryo-EM studies demonstrated the allosteric effect of a mutation situated ~85 Å away from the pore and identified an isoform-specific structural effect.
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Affiliation(s)
- Kavita A. Iyer
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Yifan Hu
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Ashok R. Nayak
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Nagomi Kurebayashi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Montserrat Samsó
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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6
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Lawal TA, Wires ES, Terry NL, Dowling JJ, Todd JJ. Preclinical model systems of ryanodine receptor 1-related myopathies and malignant hyperthermia: a comprehensive scoping review of works published 1990-2019. Orphanet J Rare Dis 2020; 15:113. [PMID: 32381029 PMCID: PMC7204063 DOI: 10.1186/s13023-020-01384-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/14/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pathogenic variations in the gene encoding the skeletal muscle ryanodine receptor (RyR1) are associated with malignant hyperthermia (MH) susceptibility, a life-threatening hypermetabolic condition and RYR1-related myopathies (RYR1-RM), a spectrum of rare neuromuscular disorders. In RYR1-RM, intracellular calcium dysregulation, post-translational modifications, and decreased protein expression lead to a heterogenous clinical presentation including proximal muscle weakness, contractures, scoliosis, respiratory insufficiency, and ophthalmoplegia. Preclinical model systems of RYR1-RM and MH have been developed to better understand underlying pathomechanisms and test potential therapeutics. METHODS We conducted a comprehensive scoping review of scientific literature pertaining to RYR1-RM and MH preclinical model systems in accordance with the PRISMA Scoping Reviews Checklist and the framework proposed by Arksey and O'Malley. Two major electronic databases (PubMed and EMBASE) were searched without language restriction for articles and abstracts published between January 1, 1990 and July 3, 2019. RESULTS Our search yielded 5049 publications from which 262 were included in this review. A majority of variants tested in RYR1 preclinical models were localized to established MH/central core disease (MH/CCD) hot spots. A total of 250 unique RYR1 variations were reported in human/rodent/porcine models with 95% being missense substitutions. The most frequently reported RYR1 variant was R614C/R615C (human/porcine total n = 39), followed by Y523S/Y524S (rabbit/mouse total n = 30), I4898T/I4897T/I4895T (human/rabbit/mouse total n = 20), and R163C/R165C (human/mouse total n = 18). The dyspedic mouse was utilized by 47% of publications in the rodent category and its RyR1-null (1B5) myotubes were transfected in 23% of publications in the cellular model category. In studies of transfected HEK-293 cells, 57% of RYR1 variations affected the RyR1 channel and activation core domain. A total of 15 RYR1 mutant mouse strains were identified of which ten were heterozygous, three were compound heterozygous, and a further two were knockout. Porcine, avian, zebrafish, C. elegans, canine, equine, and drosophila model systems were also reported. CONCLUSIONS Over the past 30 years, there were 262 publications on MH and RYR1-RM preclinical model systems featuring more than 200 unique RYR1 variations tested in a broad range of species. Findings from these studies have set the foundation for therapeutic development for MH and RYR1-RM.
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Affiliation(s)
- Tokunbor A Lawal
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Emily S Wires
- National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Nancy L Terry
- National Institutes of Health Library, National Institutes of Health, Bethesda, MD, USA
| | - James J Dowling
- Program for Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Joshua J Todd
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, 20892, USA.
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7
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Perez CF, Eltit JM, Lopez JR, Bodnár D, Dulhunty AF, Aditya S, Casarotto MG. Functional and structural characterization of a novel malignant hyperthermia-susceptible variant of DHPR-β 1a subunit (CACNB1). Am J Physiol Cell Physiol 2017; 314:C323-C333. [PMID: 29212769 DOI: 10.1152/ajpcell.00187.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Malignant hyperthermia (MH) susceptibility has been recently linked to a novel variant of β1a subunit of the dihydropyridine receptor (DHPR), a channel essential for Ca2+ regulation in skeletal muscle. Here we evaluate the effect of the mutant variant V156A on the structure/function of DHPR β1a subunit and assess its role on Ca2+ metabolism of cultured myotubes. Using differential scanning fluorimetry, we show that mutation V156A causes a significant reduction in thermal stability of the Src homology 3/guanylate kinase core domain of β1a subunit. Expression of the variant subunit in β1-null mouse myotubes resulted in increased sensitivity to caffeine stimulation. Whole cell patch-clamp analysis of β1a-V156A-expressing myotubes revealed a -2 mV shift in voltage dependence of channel activation, but no changes in Ca2+ conductance, current kinetics, or sarcoplasmic reticulum Ca2+ load were observed. Measurement of resting free Ca2+ and Na+ concentrations shows that both cations were significantly elevated in β1a-V156A-expressing myotubes and that these changes were linked to increased rates of plasmalemmal Ca2+ entry through Na+/Ca2+ exchanger and/or transient receptor potential canonical channels. Overall, our data show that mutant variant V156A results in instability of protein subdomains of β1a subunit leading to a phenotype of Ca2+ dysregulation that partly resembles that of other MH-linked mutations of DHPR α1S subunit. These data prove that homozygous expression of variant β1a-V156A has the potential to be a pathological variant, although it may require other gene defects to cause a full MH phenotype.
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Affiliation(s)
- Claudio F Perez
- Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School , Boston, Massachusetts
| | - Jose M Eltit
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University , Richmond, Virginia
| | - Jose R Lopez
- Department of Molecular Biosciences, University of California , Davis, California
| | - Dóra Bodnár
- Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School , Boston, Massachusetts
| | - Angela F Dulhunty
- John Curtin School of Medical Research, Australian National University , Canberra , Australia
| | - Shouvik Aditya
- John Curtin School of Medical Research, Australian National University , Canberra , Australia
| | - Marco G Casarotto
- John Curtin School of Medical Research, Australian National University , Canberra , Australia
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8
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Popovski ZT, Tanaskovska B, Miskoska-Milevska E, Andonov S, Domazetovska S. Associations of biochemical changes and maternal traits with mutation 1843 (C>T) in the RYR1 gene as a common cause for porcine stress syndrome. Balkan J Med Genet 2016; 19:75-80. [PMID: 28289592 PMCID: PMC5343334 DOI: 10.1515/bjmg-2016-0039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Stress syndrome is usually caused by a mutation in the ryanodine receptor gene (ryr1) and it is widely studied in humans and swine populations. The protein product of this gene plays a crucial role in the regulation of calcium transport in muscle cells. A G>T mutation in the human ryr1 gene, which results in the replacement of a conserved arginine at position 614 where a leucine occurs at the same position as the previously identified Arg→Cys mutation reported in all cases of porcine stress syndrome (PSS). Porcine stress syndrome affects biochemical pathways in stress-susceptible individuals during a stress episode and some biochemical parameters that were used as markers for diagnostic purposes. Also, PSS has remarkable influence on the maternal characteristics of sows. This study dealt with different genotypes for PSS and its association with possible biochemical changes and maternal traits of sows. Seventy-three reproductive sows genotyped for PSS by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were included in this survey. Sixty of them were stress-free (NN), 11 were heterozygous carriers (Nn) and two animals were homozygous (nn) for the 1843 (C>T) mutation. Significant differences in non stress induced animals with different PSS genotypes were found in the values of creatine phoshokinase (CPK), lactate dehydrogenase (LDH), alkaline phosphatase (AP) and aspartate aminotransferase (AST). Regarding the maternal traits, our study showed that stress susceptible animals (nn) have an increased number of stillborn piglets and a reduced number of newborn piglets compared with heterozygous and normal animals.
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Affiliation(s)
- ZT Popovski
- Department of Biochemistry and Genetic Engineering, Faculty of Agriculture and Food Sciences, Skopje, Republic of Macedonia
| | - B Tanaskovska
- Department of Biochemistry and Genetic Engineering, Faculty of Agriculture and Food Sciences, Skopje, Republic of Macedonia
| | - E Miskoska-Milevska
- Food Department, Faculty of Agriculture and Food Sciences, Skopje, Republic of Macedonia
| | - S Andonov
- Livestock Department, Faculty of Agriculture and Food Sciences, Skopje, Republic of Macedonia
| | - S Domazetovska
- Faculty of Medicine, Institute of Clinical Biochemistry, Skopje, Republic of Macedonia
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9
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Retrograde Coupling: Muscle's Orphan Signaling Pathway? Biophys J 2016; 110:870-1. [PMID: 26910422 DOI: 10.1016/j.bpj.2015.12.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 12/29/2015] [Accepted: 12/30/2015] [Indexed: 12/28/2022] Open
Abstract
In skeletal muscle excitation-contraction coupling, a voltage-gated calcium channel directly activates opening of the calcium release channel (RyR1) in the sarcoplasmic reticulum that supplies the calcium signal triggering contraction. In addition, a retrograde signal from the RyR1 facilitates gating of the voltage-gated calcium channel. Recent studies of RyR1 mutants, including the article by Bannister et al. in this issue of the Biophysical Journal, advance our understanding of the signaling mechanism, although the physiological significance of retrograde coupling remains elusive.
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10
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Hernández-Ochoa EO, Pratt SJP, Lovering RM, Schneider MF. Critical Role of Intracellular RyR1 Calcium Release Channels in Skeletal Muscle Function and Disease. Front Physiol 2016; 6:420. [PMID: 26793121 PMCID: PMC4709859 DOI: 10.3389/fphys.2015.00420] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/21/2015] [Indexed: 01/25/2023] Open
Abstract
The skeletal muscle Ca2+ release channel, also known as ryanodine receptor type 1 (RyR1), is the largest ion channel protein known and is crucial for effective skeletal muscle contractile activation. RyR1 function is controlled by Cav1.1, a voltage gated Ca2+ channel that works mainly as a voltage sensor for RyR1 activity during skeletal muscle contraction and is also fine-tuned by Ca2+, several intracellular compounds (e.g., ATP), and modulatory proteins (e.g., calmodulin). Dominant and recessive mutations in RyR1, as well as acquired channel alterations, are the underlying cause of various skeletal muscle diseases. The aim of this mini review is to summarize several current aspects of RyR1 function, structure, regulation, and to describe the most common diseases caused by hereditary or acquired RyR1 malfunction.
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Affiliation(s)
- Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Stephen J P Pratt
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Baltimore, MD, USA
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11
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Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K. Malignant hyperthermia: a review. Orphanet J Rare Dis 2015; 10:93. [PMID: 26238698 PMCID: PMC4524368 DOI: 10.1186/s13023-015-0310-1] [Citation(s) in RCA: 296] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 07/22/2015] [Indexed: 02/06/2023] Open
Abstract
Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as halothane, sevoflurane, desflurane, isoflurane and the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stressors such as vigorous exercise and heat. The incidence of MH reactions ranges from 1:10,000 to 1: 250,000 anesthetics. However, the prevalence of the genetic abnormalities may be as great as one in 400 individuals. MH affects humans, certain pig breeds, dogs and horses. The classic signs of MH include hyperthermia, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, hyperkalaemia, muscle rigidity, and rhabdomyolysis, all related to a hypermetabolic response. The syndrome is likely to be fatal if untreated. An increase in end-tidal carbon dioxide despite increased minute ventilation provides an early diagnostic clue. In humans the syndrome is inherited in an autosomal dominant pattern, while in pigs it is autosomal recessive. Uncontrolled rise of myoplasmic calcium, which activates biochemical processes related to muscle activation leads to the pathophysiologic changes. In most cases, the syndrome is caused by a defect in the ryanodine receptor. Over 400 variants have been identified in the RYR1 gene located on chromosome 19q13.1, and at least 34 are causal for MH. Less than 1 % of variants have been found in CACNA1S but not all of these are causal. Diagnostic testing involves the in vitro contracture response of biopsied muscle to halothane, caffeine, and in some centres ryanodine and 4-chloro-m-cresol. Elucidation of the genetic changes has led to the introduction of DNA testing for susceptibility to MH. Dantrolene sodium is a specific antagonist and should be available wherever general anesthesia is administered. Increased understanding of the clinical manifestation and pathophysiology of the syndrome, has lead to the mortality decreasing from 80 % thirty years ago to <5 % in 2006.
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Affiliation(s)
- Henry Rosenberg
- Department of Medical Education and Clinical Research, Saint Barnabas Medical Center, Livingston, NJ, 07039, USA.
| | - Neil Pollock
- Department of Anesthesia and Intensive Care, Palmerston North Hospital, Palmerston North, New Zealand.
| | - Anja Schiemann
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
| | - Terasa Bulger
- Department of Anesthesia and Intensive Care, Palmerston North Hospital, Palmerston North, New Zealand.
| | - Kathryn Stowell
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
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12
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Eltit JM, Franzini-Armstrong C, Perez CF. Amino acid residues 489-503 of dihydropyridine receptor (DHPR) β1a subunit are critical for structural communication between the skeletal muscle DHPR complex and type 1 ryanodine receptor. J Biol Chem 2014; 289:36116-24. [PMID: 25384984 DOI: 10.1074/jbc.m114.615526] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The β1a subunit is a cytoplasmic component of the dihydropyridine receptor (DHPR) complex that plays an essential role in skeletal muscle excitation-contraction (EC) coupling. Here we investigate the role of the C-terminal end of this auxiliary subunit in the functional and structural communication between the DHPR and the Ca(2+) release channel (RyR1). Progressive truncation of the β1a C terminus showed that deletion of amino acid residues Gln(489) to Trp(503) resulted in a loss of depolarization-induced Ca(2+) release, a severe reduction of L-type Ca(2+) currents, and a lack of tetrad formation as evaluated by freeze-fracture analysis. However, deletion of this domain did not affect expression/targeting or density (Qmax) of the DHPR-α1S subunit to the plasma membrane. Within this motif, triple alanine substitution of residues Leu(496), Leu(500), and Trp(503), which are thought to mediate direct β1a-RyR1 interactions, weakened EC coupling but did not replicate the truncated phenotype. Therefore, these data demonstrate that an amino acid segment encompassing sequence (489)QVQVLTSLRRNLSFW(503) of β1a contains critical determinant(s) for the physical link of DHPR and RyR1, further confirming a direct correspondence between DHPR positioning and DHPR/RyR functional interactions. In addition, our data strongly suggest that the motif Leu(496)-Leu(500)-Trp(503) within the β1a C-terminal tail plays a nonessential role in the bidirectional DHPR/RyR1 signaling that supports skeletal-type EC coupling.
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Affiliation(s)
- Jose M Eltit
- the Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virgina 23298, and
| | - Clara Franzini-Armstrong
- the Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Claudio F Perez
- From the Department of Anesthesiology Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115,
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13
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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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14
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Malignant hyperthermia susceptibility arising from altered resting coupling between the skeletal muscle L-type Ca2+ channel and the type 1 ryanodine receptor. Proc Natl Acad Sci U S A 2012; 109:7923-8. [PMID: 22547813 DOI: 10.1073/pnas.1119207109] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Malignant hyperthermia (MH) susceptibility is a dominantly inherited disorder in which volatile anesthetics trigger aberrant Ca(2+) release in skeletal muscle and a potentially fatal rise in perioperative body temperature. Mutations causing MH susceptibility have been identified in two proteins critical for excitation-contraction (EC) coupling, the type 1 ryanodine receptor (RyR1) and Ca(V)1.1, the principal subunit of the L-type Ca(2+) channel. All of the mutations that have been characterized previously augment EC coupling and/or increase the rate of L-type Ca(2+) entry. The Ca(V)1.1 mutation R174W associated with MH susceptibility occurs at the innermost basic residue of the IS4 voltage-sensing helix, a residue conserved among all Ca(V) channels [Carpenter D, et al. (2009) BMC Med Genet 10:104-115.]. To define the functional consequences of this mutation, we expressed it in dysgenic (Ca(V)1.1 null) myotubes. Unlike previously described MH-linked mutations in Ca(V)1.1, R174W ablated the L-type current and had no effect on EC coupling. Nonetheless, R174W increased sensitivity of Ca(2+) release to caffeine (used for MH diagnostic in vitro testing) and to volatile anesthetics. Moreover, in Ca(V)1.1 R174W-expressing myotubes, resting myoplasmic Ca(2+) levels were elevated, and sarcoplasmic reticulum (SR) stores were partially depleted, compared with myotubes expressing wild-type Ca(V)1.1. Our results indicate that Ca(V)1.1 functions not only to activate RyR1 during EC coupling, but also to suppress resting RyR1-mediated Ca(2+) leak from the SR, and that perturbation of Ca(V)1.1 negative regulation of RyR1 leak identifies a unique mechanism that can sensitize muscle cells to MH triggers.
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15
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Barrientos GC, Feng W, Truong K, Matthaei KI, Yang T, Allen PD, Lopez JR, Pessah IN. Gene dose influences cellular and calcium channel dysregulation in heterozygous and homozygous T4826I-RYR1 malignant hyperthermia-susceptible muscle. J Biol Chem 2011; 287:2863-76. [PMID: 22139840 DOI: 10.1074/jbc.m111.307926] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Malignant hyperthermia susceptibility (MHS) is primarily conferred by mutations within ryanodine receptor type 1 (RYR1). Here we address how the MHS mutation T4826I within the S4-S5 linker influences excitation-contraction coupling and resting myoplasmic Ca(2+) concentration ([Ca(2+)](rest)) in flexor digitorum brevis (FDB) and vastus lateralis prepared from heterozygous (Het) and homozygous (Hom) T4826I-RYR1 knock-in mice (Yuen, B. T., Boncompagni, S., Feng, W., Yang, T., Lopez, J. R., Matthaei, K. I., Goth, S. R., Protasi, F., Franzini-Armstrong, C., Allen, P. D., and Pessah, I. N. (2011) FASEB J. doi:22131268). FDB responses to electrical stimuli and acute halothane (0.1%, v/v) exposure showed a rank order of Hom ≫ Het ≫ WT. Release of Ca(2+) from the sarcoplasmic reticulum and Ca(2+) entry contributed to halothane-triggered increases in [Ca(2+)](rest) in Hom FDBs and elicited pronounced Ca(2+) oscillations in ∼30% of FDBs tested. Genotype contributed significantly elevated [Ca(2+)](rest) (Hom > Het > WT) measured in vivo using ion-selective microelectrodes. Het and Hom oxygen consumption rates measured in intact myotubes using the Seahorse Bioscience (Billerica, MA) flux analyzer and mitochondrial content measured with MitoTracker were lower than WT, whereas total cellular calpain activity was higher than WT. Muscle membranes did not differ in RYR1 expression nor in Ser(2844) phosphorylation among the genotypes. Single channel analysis showed highly divergent gating behavior with Hom and WT favoring open and closed states, respectively, whereas Het exhibited heterogeneous gating behaviors. [(3)H]Ryanodine binding analysis revealed a gene dose influence on binding density and regulation by Ca(2+), Mg(2+), and temperature. Pronounced abnormalities inherent in T4826I-RYR1 channels confer MHS and promote basal disturbances of excitation-contraction coupling, [Ca(2+)](rest), and oxygen consumption rates. Considering that both Het and Hom T4826I-RYR1 mice are viable, the remarkable isolated single channel dysfunction mediated through this mutation in S4-S5 cytoplasmic linker must be highly regulated in vivo.
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Affiliation(s)
- Genaro C Barrientos
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616, USA
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16
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Yuen B, Boncompagni S, Feng W, Yang T, Lopez JR, Matthaei KI, Goth SR, Protasi F, Franzini-Armstrong C, Allen PD, Pessah IN. Mice expressing T4826I-RYR1 are viable but exhibit sex- and genotype-dependent susceptibility to malignant hyperthermia and muscle damage. FASEB J 2011; 26:1311-22. [PMID: 22131268 DOI: 10.1096/fj.11-197582] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mutation T4825I in the type 1 ryanodine receptor (RYR1(T4825I/+)) confers human malignant hyperthermia susceptibility (MHS). We report a knock-in mouse line that expresses the isogenetic mutation T4826I. Heterozygous RYR1(T4826I/+) (Het) or homozygous RYR1(T4826I/T4826I) (Hom) mice are fully viable under typical rearing conditions but exhibit genotype- and sex-dependent susceptibility to environmental conditions that trigger MH. Hom mice maintain higher core temperatures than WT in the home cage, have chronically elevated myoplasmic[Ca(2+)](rest), and present muscle damage in soleus with a strong sex bias. Mice subjected to heat stress in an enclosed 37°C chamber fail to trigger MH regardless of genotype, whereas heat stress at 41°C invariably triggers fulminant MH in Hom, but not Het, mice within 20 min. WT and Het female mice fail to maintain euthermic body temperature when placed atop a bed whose surface is 37°C during halothane anesthesia (1.75%) and have no hyperthermic response, whereas 100% Hom mice of either sex and 17% of the Het males develop fulminant MH. WT mice placed on a 41°C bed maintain body temperature while being administered halothane, and 40% of the Het females and 100% of the Het males develop fulminant MH within 40 min. Myopathic alterations in soleus were apparent by 12 mo, including abnormally distributed and enlarged mitochondria, deeply infolded sarcolemma, and frequent Z-line streaming regions, which were more severe in males. These data demonstrate that an MHS mutation within the S4-S5 cytoplasmic linker of RYR1 confers genotype- and sex-dependent susceptibility to pharmacological and environmental stressors that trigger fulminant MH and promote myopathy.
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Affiliation(s)
- Benjamin Yuen
- Department of Veterinary Molecular Biosciences, University of California, Davis, California, USA
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17
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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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18
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Olojo RO, Hernández-Ochoa EO, Ikemoto N, Schneider MF. Effects of conformational peptide probe DP4 on bidirectional signaling between DHPR and RyR1 calcium channels in voltage-clamped skeletal muscle fibers. Biophys J 2011; 100:2367-77. [PMID: 21575570 DOI: 10.1016/j.bpj.2011.04.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Revised: 03/21/2011] [Accepted: 04/04/2011] [Indexed: 01/09/2023] Open
Abstract
In skeletal muscle, excitation-contraction coupling involves the activation of dihydropyridine receptors (DHPR) and type-1 ryanodine receptors (RyR1) to produce depolarization-dependent sarcoplasmic reticulum Ca²⁺ release via orthograde signaling. Another form of DHPR-RyR1 communication is retrograde signaling, in which RyRs modulate the gating of DHPR. DP4 (domain peptide 4), is a peptide corresponding to residues Leu²⁴⁴²-Pro²⁴⁷⁷ of the central domain of the RyR1 that produces RyR1 channel destabilization. Here we explore the effects of DP4 on orthograde excitation-contraction coupling and retrograde RyR1-DHPR signaling in isolated murine muscle fibers. Intracellular dialysis of DP4 increased the peak amplitude of Ca²⁺ release during step depolarizations by 64% without affecting its voltage-dependence or kinetics, and also caused a similar increase in Ca²⁺ release during an action potential waveform. DP4 did not modify either the amplitude or the voltage-dependence of the intramembrane charge movement. However, DP4 augmented DHPR Ca²⁺ current density without affecting its voltage-dependence. Our results demonstrate that the conformational changes induced by DP4 regulate both orthograde E-C coupling and retrograde RyR1-DHPR signaling.
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Affiliation(s)
- Rotimi O Olojo
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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19
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MacLennan DH, Zvaritch E. Mechanistic models for muscle diseases and disorders originating in the sarcoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:948-64. [DOI: 10.1016/j.bbamcr.2010.11.009] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 11/11/2010] [Accepted: 11/18/2010] [Indexed: 11/29/2022]
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20
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Feng W, Barrientos GC, Cherednichenko G, Yang T, Padilla IT, Truong K, Allen PD, Lopez JR, Pessah IN. Functional and biochemical properties of ryanodine receptor type 1 channels from heterozygous R163C malignant hyperthermia-susceptible mice. Mol Pharmacol 2010; 79:420-31. [PMID: 21156754 DOI: 10.1124/mol.110.067959] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutations in ryanodine receptor type 1 (RyR1) confer malignant hyperthermia susceptibility. How inherent impairments in Ca(2+) channel regulation affect skeletal muscle function in myotubes and adult fibers under basal (nontriggering) conditions are not understood. Myotubes, adult flexor digitorum brevis (FDB) fibers, and sarcoplasmic reticulum skeletal membranes were isolated from heterozygous knockin R163C and wild-type (WT) mice. Compared with WT myotubules, R163C myotubes have reduced Ca(2+) transient amplitudes in response to electrical field pulses; however, R163C FDB fibers do not differ in their responses to electrical stimuli, despite heightened cellular cytoplasmic resting Ca(2+) ([Ca(2+)](rest)) and sensitivity to halothane. Immunoblotting of membranes from each genotype shows similar expression of RyR1, FK506 binding protein 12 kDa, and Ca(2+)-ATPase, but RyR1 (2844)Ser phosphorylation in R163C muscle is 31% higher than that of WT muscle (p < 0.001). RyR1 channels reconstituted in planar lipid bilayers reveal ∼65% of R163C channels exhibit ≥2-fold greater open probability (P(o)) than WT, with prolonged mean open dwell times and shortened closed dwell times. [(3)H]Ryanodine (Ry) binding and single-channel analyses show that R163C-RyR1 has altered regulation compared with WT: 1) 3-fold higher sensitivity to Ca(2+) activation; 2) 2-fold greater [(3)H]Ry receptor occupancy; 3) comparatively higher channel activity, even in reducing glutathione buffer; 4) enhanced RyR1 activity both at 25 and 37°C; and 5) elevated cytoplasmic [Ca(2+)](rest). R163C channels are inherently more active than WT channels, a functional impairment that cannot be reversed by dephosphorylation with protein phosphatase. Dysregulated R163C channels produce a more overt phenotype in myotubes than in adult fibers in the absence of triggering agents, suggesting tighter negative regulation of R163C-RyR1 within the Ca(2+) release unit of adult fibers.
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Affiliation(s)
- Wei Feng
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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21
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Estève E, Eltit JM, Bannister RA, Liu K, Pessah IN, Beam KG, Allen PD, López JR. A malignant hyperthermia-inducing mutation in RYR1 (R163C): alterations in Ca2+ entry, release, and retrograde signaling to the DHPR. J Gen Physiol 2010; 135:619-28. [PMID: 20479110 PMCID: PMC2888056 DOI: 10.1085/jgp.200910328] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 04/21/2010] [Indexed: 11/20/2022] Open
Abstract
Bidirectional signaling between the sarcolemmal L-type Ca(2+) channel (1,4-dihydropyridine receptor [DHPR]) and the sarcoplasmic reticulum (SR) Ca(2+) release channel (type 1 ryanodine receptor [RYR1]) of skeletal muscle is essential for excitation-contraction coupling (ECC) and is a well-understood prototype of conformational coupling. Mutations in either channel alter coupling fidelity and with an added pharmacologic stimulus or stress can trigger malignant hyperthermia (MH). In this study, we measured the response of wild-type (WT), heterozygous (Het), or homozygous (Hom) RYR1-R163C knock-in mouse myotubes to maintained K(+) depolarization. The new findings are: (a) For all three genotypes, Ca(2+) transients decay during prolonged depolarization, and this decay is not a consequence of SR depletion or RYR1 inactivation. (b) The R163C mutation retards the decay rate with a rank order WT > Het > Hom. (c) The removal of external Ca(2+) or the addition of Ca(2+) entry blockers (nifedipine, SKF96365, and Ni(2+)) enhanced the rate of decay in all genotypes. (d) When Ca(2+) entry is blocked, the decay rates are slower for Hom and Het than WT, indicating that the rate of inactivation of ECC is affected by the R163C mutation and is genotype dependent (WT > Het > Hom). (e) Reduced ECC inactivation in Het and Hom myotubes was shown directly using two identical K(+) depolarizations separated by varying time intervals. These data suggest that conformational changes induced by the R163C MH mutation alter the retrograde signal that is sent from RYR1 to the DHPR, delaying the inactivation of the DHPR voltage sensor.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Calcium/metabolism
- Calcium Channel Agonists/pharmacology
- Calcium Channels, L-Type/metabolism
- Calcium Signaling/drug effects
- Cell Membrane/metabolism
- Cells, Cultured
- Excitation Contraction Coupling
- Malignant Hyperthermia/genetics
- Malignant Hyperthermia/metabolism
- Malignant Hyperthermia/physiopathology
- Membrane Potentials
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Myoblasts, Skeletal/drug effects
- Myoblasts, Skeletal/metabolism
- Protein Conformation
- Ryanodine Receptor Calcium Release Channel/drug effects
- Ryanodine Receptor Calcium Release Channel/genetics
- Ryanodine Receptor Calcium Release Channel/metabolism
- Sarcoplasmic Reticulum/metabolism
- Structure-Activity Relationship
- Time Factors
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Affiliation(s)
- Eric Estève
- Department of Anesthesiology Perioperative and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115
- Université Victor Segalen Bordeaux 2, Institut National de la Santé et de la Recherche Medicale U885, Laboratoire de Physiologie Cellulaire Respiratoire, 33076 Bordeaux, France
| | - José M. Eltit
- Department of Anesthesiology Perioperative and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115
- Programa de Biologia Molecular y Celular, Instituto de Ciencias Biomedicas Facultad de Medicina, Universidad de Chile, Casilla 70005, Santiago, Chile
| | - Roger A. Bannister
- Department of Physiology and Biophysics, School of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO 80045
| | - Kai Liu
- Department of Anesthesiology Perioperative and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115
| | - Isaac N. Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616
| | - Kurt G. Beam
- Department of Physiology and Biophysics, School of Medicine, University of Colorado-Anschutz Medical Campus, Aurora, CO 80045
| | - Paul D. Allen
- Department of Anesthesiology Perioperative and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115
| | - José R. López
- Department of Anesthesiology Perioperative and Pain Medicine, Brigham and Women’s Hospital, Boston, MA 02115
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