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Abstract
In contrast to conventional hard actuators, soft actuators offer many vivid advantages, such as improved flexibility, adaptability, and reconfigurability, which are intrinsic to living systems. These properties make them particularly promising for different applications, including soft electronics, surgery, drug delivery, artificial organs, or prosthesis. The additional degree of freedom for soft actuatoric devices can be provided through the use of intelligent materials, which are able to change their structure, macroscopic properties, and shape under the influence of external signals. The use of such intelligent materials allows a substantial reduction of a device's size, which enables a number of applications that cannot be realized by externally powered systems. This review aims to provide an overview of the properties of intelligent synthetic and living/natural materials used for the fabrication of soft robotic devices. We discuss basic physical/chemical properties of the main kinds of materials (elastomers, gels, shape memory polymers and gels, liquid crystalline elastomers, semicrystalline ferroelectric polymers, gels and hydrogels, other swelling polymers, materials with volume change during melting/crystallization, materials with tunable mechanical properties, and living and naturally derived materials), how they are related to actuation and soft robotic application, and effects of micro/macro structures on shape transformation, fabrication methods, and we highlight selected applications.
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Affiliation(s)
- Indra Apsite
- Faculty of Engineering Science, Department of Biofabrication, University of Bayreuth, Ludwig Thoma Str. 36A, 95447 Bayreuth, Germany
| | - Sahar Salehi
- Department of Biomaterials, Center of Energy Technology und Materials Science, University of Bayreuth, Prof.-Rüdiger-Bormann-Straße 1, 95447 Bayreuth, Germany
| | - Leonid Ionov
- Faculty of Engineering Science, Department of Biofabrication, University of Bayreuth, Ludwig Thoma Str. 36A, 95447 Bayreuth, Germany.,Bavarian Polymer Institute, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
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2
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Hostrup M, Cairns SP, Bangsbo J. Muscle Ionic Shifts During Exercise: Implications for Fatigue and Exercise Performance. Compr Physiol 2021; 11:1895-1959. [PMID: 34190344 DOI: 10.1002/cphy.c190024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exercise causes major shifts in multiple ions (e.g., K+ , Na+ , H+ , lactate- , Ca2+ , and Cl- ) during muscle activity that contributes to development of muscle fatigue. Sarcolemmal processes can be impaired by the trans-sarcolemmal rundown of ion gradients for K+ , Na+ , and Ca2+ during fatiguing exercise, while changes in gradients for Cl- and Cl- conductance may exert either protective or detrimental effects on fatigue. Myocellular H+ accumulation may also contribute to fatigue development by lowering glycolytic rate and has been shown to act synergistically with inorganic phosphate (Pi) to compromise cross-bridge function. In addition, sarcoplasmic reticulum Ca2+ release function is severely affected by fatiguing exercise. Skeletal muscle has a multitude of ion transport systems that counter exercise-related ionic shifts of which the Na+ /K+ -ATPase is of major importance. Metabolic perturbations occurring during exercise can exacerbate trans-sarcolemmal ionic shifts, in particular for K+ and Cl- , respectively via metabolic regulation of the ATP-sensitive K+ channel (KATP ) and the chloride channel isoform 1 (ClC-1). Ion transport systems are highly adaptable to exercise training resulting in an enhanced ability to counter ionic disturbances to delay fatigue and improve exercise performance. In this article, we discuss (i) the ionic shifts occurring during exercise, (ii) the role of ion transport systems in skeletal muscle for ionic regulation, (iii) how ionic disturbances affect sarcolemmal processes and muscle fatigue, (iv) how metabolic perturbations exacerbate ionic shifts during exercise, and (v) how pharmacological manipulation and exercise training regulate ion transport systems to influence exercise performance in humans. © 2021 American Physiological Society. Compr Physiol 11:1895-1959, 2021.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Simeon Peter Cairns
- SPRINZ, School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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3
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Abstract
Drug metabolizing enzymes catalyze the biotransformation of many of drugs and chemicals. The drug metabolizing enzymes are distributed among several evolutionary families and catalyze a range of detoxication reactions, including oxidation/reduction, conjugative, and hydrolytic reactions that serve to detoxify potentially toxic compounds. This detoxication function requires that drug metabolizing enzymes exhibit substrate promiscuity. In addition to their catalytic functions, many drug metabolizing enzymes possess functions unrelated to or in addition to catalysis. Such proteins are termed 'moonlighting proteins' and are defined as proteins with multiple biochemical or biophysical functions that reside in a single protein. This review discusses the diverse moonlighting functions of drug metabolizing enzymes and the roles they play in physiological functions relating to reproduction, vision, cell signaling, cancer, and transport. Further research will likely reveal new examples of moonlighting functions of drug metabolizing enzymes.
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Affiliation(s)
- Philip G Board
- John Curtin School of Medical Research, ANU College of Health and Medicine, The Australian National University, Canberra, ACT, Australia
| | - M W Anders
- Department of Pharmacology and Physiology, University of Rochester Medical Center, New York, NY, USA
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4
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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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Vellecco V, Armogida C, Bucci M. Hydrogen sulfide pathway and skeletal muscle: an introductory review. Br J Pharmacol 2018; 175:3090-3099. [PMID: 29767441 PMCID: PMC6031874 DOI: 10.1111/bph.14358] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/18/2018] [Accepted: 04/30/2018] [Indexed: 12/13/2022] Open
Abstract
The presence of the H2 S pathway in skeletal muscle (SKM) has recently been established. SKM expresses the three constitutive H2 S-generating enzymes in animals and humans, and it actively produces H2 S. The main, recognized molecular targets of H2 S, that is, potassium channels and PDEs, have been evaluated in SKM physiology in order to hypothesize a role for H2 S signalling. SKM dysfunctions, including muscular dystrophy and malignant hyperthermia, have also been evaluated as conditions in which the H2 S and transsulfuration pathways have been suggested to be involved. The intrinsic complexity of the molecular mechanisms involved in excitation-contraction (E-C) coupling together with the scarcity of preclinical models of SKM-related disorders have hampered any advances in the knowledge of SKM function. Here, we have addressed the role of the H2 S pathway in E-C coupling and the relative importance of cystathionine β-synthase, cistathionine γ-lyase and 3-mercaptopyruvate sulfurtransferase in SKM diseases.
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Affiliation(s)
- Valentina Vellecco
- Department of Pharmacy, School of Medicine, University of Naples 'Federico II', Naples, 80131, Italy
| | - Chiara Armogida
- Department of Pharmacy, School of Medicine, University of Naples 'Federico II', Naples, 80131, Italy
| | - Mariarosaria Bucci
- Department of Pharmacy, School of Medicine, University of Naples 'Federico II', Naples, 80131, Italy
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6
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Agrawal A, Suryakumar G, Rathor R. Role of defective Ca 2+ signaling in skeletal muscle weakness: Pharmacological implications. J Cell Commun Signal 2018; 12:645-659. [PMID: 29982883 DOI: 10.1007/s12079-018-0477-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/27/2018] [Indexed: 01/19/2023] Open
Abstract
The misbehaving attitude of Ca2+ signaling pathways could be the probable reason in many muscular disorders such as myopathies, systemic disorders like hypoxia, sepsis, cachexia, sarcopenia, heart failure, and dystrophy. The present review throws light upon the calcium flux regulating signaling channels like ryanodine receptor complex (RyR1), SERCA (Sarco-endoplasmic Reticulum Calcium ATPase), DHPR (Dihydropyridine Receptor) or Cav1.1 and Na+/Ca2+ exchange pump in detail and how remodelling of these channels contribute towards disturbed calcium homeostasis. Understanding these pathways will further provide an insight for establishing new therapeutic approaches for the prevention and treatment of muscle atrophy under stress conditions, targeting calcium ion channels and associated regulatory proteins.
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Affiliation(s)
- Akanksha Agrawal
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Geetha Suryakumar
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Richa Rathor
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India.
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7
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Ostrovidov S, Ebrahimi M, Bae H, Nguyen HK, Salehi S, Kim SB, Kumatani A, Matsue T, Shi X, Nakajima K, Hidema S, Osanai M, Khademhosseini A. Gelatin-Polyaniline Composite Nanofibers Enhanced Excitation-Contraction Coupling System Maturation in Myotubes. ACS APPLIED MATERIALS & INTERFACES 2017; 9:42444-42458. [PMID: 29023089 DOI: 10.1021/acsami.7b03979] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this study, composite gelatin-polyaniline (PANI) nanofibers doped with camphorsulfonic acid (CSA) were fabricated by electrospinning and used as substrates to culture C2C12 myoblast cells. We observed enhanced myotube formation on composite gelatin-PANI nanofibers compared to gelatin nanofibers, concomitantly with enhanced myotube maturation. Thus, in myotubes, intracellular organization, colocalization of the dihydropyridine receptor (DHPR) and ryanodine receptor (RyR), expression of genes correlated to the excitation-contraction (E-C) coupling apparatus, calcium transients, and myotube contractibility were increased. Such composite material scaffolds combining topographical and electrically conductive cues may be useful to direct skeletal muscle cell organization and to improve cellular maturation, functionality, and tissue formation.
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Affiliation(s)
- Serge Ostrovidov
- WPI-Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School , Cambridge, Massachusetts 02139, United States
| | - Majid Ebrahimi
- WPI-Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
| | - Hojae Bae
- KU Convergence Science and Technology Institute, Department of Stem Cell and Regenerative Biotechnology, Konkuk University , Hwayang-dong, Kwangjin-gu, Seoul 05029, Republic of Korea
| | - Hung Kim Nguyen
- WPI-Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
| | - Sahar Salehi
- WPI-Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
- Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften, Universität Bayreuth , Bayreuth 95440, Germany
| | - Sang Bok Kim
- Department of Eco-Machinery system, Korea Institute of Machinery and Materials , Daejeon 305-343, Republic of Korea
| | - Akichika Kumatani
- WPI-Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
- Graduate School of Environmental Studies, Tohoku University , Sendai 980-8579, Japan
| | - Tomokazu Matsue
- WPI-Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
- Graduate School of Environmental Studies, Tohoku University , Sendai 980-8579, Japan
| | - Xuetao Shi
- National Engineering Research Centre for Tissue Restoration and Reconstruction, South China University of Technology , Guangzhou 510006, PR China
| | - Ken Nakajima
- School of Materials and Chemical Technology, Tokyo Institute of Technology , Tokyo 152-8550, Japan
| | - Shizu Hidema
- Graduate School of Agricultural Science, Department of Molecular and Cell Biology, Tohoku University , Sendai 981-8555, Japan
| | - Makoto Osanai
- Department of Radiological Imaging and Informatics, Tohoku University Graduate School of Medicine , Sendai 980-8575, Japan
- Department of Intelligent Biomedical Systems Engineering, Graduate School of Biomedical Engineering, Tohoku University , Sendai 980-8575, Japan
| | - Ali Khademhosseini
- WPI-Advanced Institute for Materials Research, Tohoku University , Sendai 980-8577, Japan
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School , Cambridge, Massachusetts 02139, United States
- KU Convergence Science and Technology Institute, Department of Stem Cell and Regenerative Biotechnology, Konkuk University , Hwayang-dong, Kwangjin-gu, Seoul 05029, Republic of Korea
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
- Wyss Institute for Biologically Inspired Engineering, Harvard University , Boston, Massachusetts 02115, United States
- Department of Physics, Faculty of Science, King Abdulaziz University , Jeddah 21569, Saudi Arabia
- California NanoSystems Institute (CNSI), and Center for Minimally Invasive Therapeutics (C-MIT), Department of Bioengineering and Department of Radiology, University of California , Los Angeles, California 90095, United States
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8
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Simkin D, Robin G, Giuliano S, Vukolic A, Moceri P, Guy N, Wagner KD, Lacampagne A, Allard B, Bendahhou S. Andersen's syndrome mutants produce a knockdown of inwardly rectifying K + channel in mouse skeletal muscle in vivo. Cell Tissue Res 2017; 371:309-323. [PMID: 29018970 DOI: 10.1007/s00441-017-2696-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 09/05/2017] [Indexed: 11/30/2022]
Abstract
Andersen's syndrome (AS) is a rare autosomal disorder that has been defined by the triad of periodic paralysis, cardiac arrhythmia, and developmental anomalies. AS has been directly linked to over 40 different autosomal dominant negative loss-of-function mutations in the KCNJ2 gene, encoding for the tetrameric strong inward rectifying K+ channel KIR2.1. While KIR2.1 channels have been suggested to contribute to setting the resting membrane potential (RMP) and to control the duration of the action potential (AP) in skeletal and cardiac muscle, the mechanism by which AS mutations produce such complex pathophysiological symptoms is poorly understood. Thus, we use an adenoviral transduction strategy to study in vivo subcellular distribution of wild-type (WT) and AS-associated mutant KIR2.1 channels in mouse skeletal muscle. We determined that WT and D71V AS mutant KIR2.1 channels are localized to the sarcolemma and the transverse tubules (T-tubules) of skeletal muscle fibers, while the ∆314-315 AS KIR2.1 mutation prevents proper trafficking of the homo- or hetero-meric channel complexes. Whole-cell voltage-clamp recordings in individual skeletal muscle fibers confirmed the reduction of inwardly rectifying K+ current (IK1) after transduction with ∆314-315 KIR2.1 as compared to WT channels. Analysis of skeletal muscle function revealed reduced force generation during isometric contraction as well as reduced resistance to muscle fatigue in extensor digitorum longus muscles transduced with AS mutant KIR2.1. Together, these results suggest that KIR2.1 channels may be involved in the excitation-contraction coupling process required for proper skeletal muscle function. Our findings provide clues to mechanisms associated with periodic paralysis in AS.
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Affiliation(s)
- Dina Simkin
- UMR 7370 CNRS, LP2M, Laboratoire d'Excellence - ICST, Université Côte d'Azur, Faculté de Médecine, 06107, Nice, France.,Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Gaëlle Robin
- UMR CNRS 5534, Université Claude Bernard Lyon 1, 69622, Lyon, France
| | - Serena Giuliano
- UMR 7370 CNRS, LP2M, Laboratoire d'Excellence - ICST, Université Côte d'Azur, Faculté de Médecine, 06107, Nice, France
| | - Ana Vukolic
- Institute for Molecular Health Science, ETH Zurich, 8093, Zurich, Switzerland
| | - Pamela Moceri
- UMR 7370 CNRS, LP2M, Laboratoire d'Excellence - ICST, Université Côte d'Azur, Faculté de Médecine, 06107, Nice, France.,Service de Cardiologie, Pasteur Hospital, CHU de Nice, 06107, Nice, France
| | - Nicolas Guy
- UMR 7275 CNRS, IPMC, Université Côte d'Azur, 06560, Valbonne, France
| | - Kay-Dietrich Wagner
- UMR 7284 CNRS, INSERM, IBV, Université Côte d'Azur, Faculté de Médecine, 06107, Nice, France
| | - Alain Lacampagne
- INSERM U1046, UMR CNRS 9214, Université de Montpellier, CHRU de Montpellier, 34295, Montpellier, France
| | - Bruno Allard
- UMR CNRS 5534, Université Claude Bernard Lyon 1, 69622, Lyon, France
| | - Saïd Bendahhou
- UMR 7370 CNRS, LP2M, Laboratoire d'Excellence - ICST, Université Côte d'Azur, Faculté de Médecine, 06107, Nice, France.
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9
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Hewawasam RP, Liu D, Casarotto MG, Board PG, Dulhunty AF. The GSTM2 C-Terminal Domain Depresses Contractility and Ca2+ Transients in Neonatal Rat Ventricular Cardiomyocytes. PLoS One 2016; 11:e0162415. [PMID: 27612301 PMCID: PMC5017731 DOI: 10.1371/journal.pone.0162415] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/22/2016] [Indexed: 11/25/2022] Open
Abstract
The cardiac ryanodine receptor (RyR2) is an intracellular ion channel that regulates Ca2+ release from the sarcoplasmic reticulum (SR) during excitation–contraction coupling in the heart. The glutathione transferases (GSTs) are a family of phase II detoxification enzymes with additional functions including the selective inhibition of RyR2, with therapeutic implications. The C-terminal half of GSTM2 (GSTM2C) is essential for RyR2 inhibition, and mutations F157A and Y160A within GSTM2C prevent the inhibitory action. Our objective in this investigation was to determine whether GSTM2C can enter cultured rat neonatal ventricular cardiomyocytes and influence contractility. We show that oregon green-tagged GSTM2C (at 1 μM) is internalized into the myocytes and it reduces spontaneous contraction frequency and myocyte shortening. Field stimulation of myocytes evoked contraction in the same percentage of myocytes treated either with media alone or media plus 15 μM GSTM2C. Myocyte shortening during contraction was significantly reduced by exposure to 15 μM GSTM2C, but not 5 and 10 μM GSTM2C and was unaffected by exposure to 15 μM of the mutants Y160A or F157A. The amplitude of the Ca2+ transient in the 15 μM GSTM2C - treated myocytes was significantly decreased, the rise time was significantly longer and the decay time was significantly shorter than in control myocytes. The Ca2+ transient was not altered by exposure to Y160A or F157A. The results are consistent with GSTM2C entering the myocytes and inhibiting RyR2, in a manner that indicates a possible therapeutic potential for treatment of arrhythmia in the neonatal heart.
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Affiliation(s)
- Ruwani P. Hewawasam
- John Curtin School of Medical Research, The Australian National University, GPO Box 334, Canberra City, ACT 2600, Australia
| | - Dan Liu
- John Curtin School of Medical Research, The Australian National University, GPO Box 334, Canberra City, ACT 2600, Australia
| | - Marco G. Casarotto
- John Curtin School of Medical Research, The Australian National University, GPO Box 334, Canberra City, ACT 2600, Australia
| | - Philip G. Board
- John Curtin School of Medical Research, The Australian National University, GPO Box 334, Canberra City, ACT 2600, Australia
| | - Angela F. Dulhunty
- John Curtin School of Medical Research, The Australian National University, GPO Box 334, Canberra City, ACT 2600, Australia
- * E-mail:
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10
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Samarasinghe K, Liu D, Tummala P, Cappello J, Pace SM, Arnolda L, Casarotto MG, Dulhunty AF, Board PG. Glutathione transferase M2 variants inhibit ryanodine receptor function in adult mouse cardiomyocytes. Biochem Pharmacol 2015; 97:269-80. [DOI: 10.1016/j.bcp.2015.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 08/03/2015] [Indexed: 11/16/2022]
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11
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Kim YS, Kim YB, Kim WB, Yoon BE, Shen FY, Lee SW, Soong TW, Han HC, Colwell CS, Lee CJ, Kim YI. Histamine resets the circadian clock in the suprachiasmatic nucleus through the H1R-CaV1.3-RyR pathway in the mouse. Eur J Neurosci 2015. [DOI: 10.1111/ejn.13030] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yoon Sik Kim
- Department of Physiology and Neuroscience Research Institute; Korea University College of Medicine; Seoul 136-705 Korea
| | - Young-Beom Kim
- Department of Physiology and Neuroscience Research Institute; Korea University College of Medicine; Seoul 136-705 Korea
| | - Woong Bin Kim
- Department of Physiology and Neuroscience Research Institute; Korea University College of Medicine; Seoul 136-705 Korea
| | - Bo-Eun Yoon
- Center for Neural Science and Center for Functional Connectomics; Korea Institute of Science and Technology; Seoul 136-791 Korea
- Department of Nanobiomedical Science; Dankook University; Chungnam Korea
| | - Feng-Yan Shen
- Department of Physiology and Neuroscience Research Institute; Korea University College of Medicine; Seoul 136-705 Korea
| | - Seung Won Lee
- Department of Physiology and Neuroscience Research Institute; Korea University College of Medicine; Seoul 136-705 Korea
| | - Tuck-Wah Soong
- Department of Physiology; Yong Loo Lin School of Medicine; National University of Singapore Bik MD9; Singapore Singapore
| | - Hee-Chul Han
- Department of Physiology and Neuroscience Research Institute; Korea University College of Medicine; Seoul 136-705 Korea
| | - Christopher S. Colwell
- Department of Psychiatry & Biobehavioral Sciences; University of California-Los Angeles; Los Angeles CA USA
| | - C. Justin Lee
- Center for Neural Science and Center for Functional Connectomics; Korea Institute of Science and Technology; Seoul 136-791 Korea
| | - Yang In Kim
- Department of Physiology and Neuroscience Research Institute; Korea University College of Medicine; Seoul 136-705 Korea
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12
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Rebbeck RT, Willemse H, Groom L, Casarotto MG, Board PG, Beard NA, Dirksen RT, Dulhunty AF. Regions of ryanodine receptors that influence activation by the dihydropyridine receptor β1a subunit. Skelet Muscle 2015. [PMID: 26203350 PMCID: PMC4510890 DOI: 10.1186/s13395-015-0049-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Background Although excitation-contraction (EC) coupling in skeletal muscle relies on physical activation of the skeletal ryanodine receptor (RyR1) Ca2+ release channel by dihydropyridine receptors (DHPRs), the activation pathway between the DHPR and RyR1 remains unknown. However, the pathway includes the DHPR β1a subunit which is integral to EC coupling and activates RyR1. In this manuscript, we explore the isoform specificity of β1a activation of RyRs and the β1a binding site on RyR1. Methods We used lipid bilayers to measure single channel currents and whole cell patch clamp to measure L-type Ca2+ currents and Ca2+ transients in myotubes. Results We demonstrate that both skeletal RyR1 and cardiac RyR2 channels in phospholipid bilayers are activated by 10–100 nM of the β1a subunit. Activation of RyR2 by 10 nM β1a was less than that of RyR1, suggesting a reduced affinity of RyR2 for β1a. A reduction in activation was also observed when 10 nM β1a was added to the alternatively spliced (ASI(−)) isoform of RyR1, which lacks ASI residues (A3481-Q3485). It is notable that the equivalent region of RyR2 also lacks four of five ASI residues, suggesting that the absence of these residues may contribute to the reduced 10 nM β1a activation observed for both RyR2 and ASI(−)RyR1 compared to ASI(+)RyR1. We also investigated the influence of a polybasic motif (PBM) of RyR1 (K3495KKRRDGR3502) that is located immediately downstream from the ASI residues and has been implicated in EC coupling. We confirmed that neutralizing the basic residues in the PBM (RyR1 K-Q) results in an ~50 % reduction in Ca2+ transient amplitude following expression in RyR1-null (dyspedic) myotubes and that the PBM is also required for β1a subunit activation of RyR1 channels in lipid bilayers. These results suggest that the removal of β1a subunit interaction with the PBM in RyR1 could contribute directly to ~50 % of the Ca2+ release generated during skeletal EC coupling. Conclusions We conclude that the β1a subunit likely binds to a region that is largely conserved in RyR1 and RyR2 and that this region is influenced by the presence of the ASI residues and the PBM in RyR1. Electronic supplementary material The online version of this article (doi:10.1186/s13395-015-0049-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Robyn T Rebbeck
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN USA
| | - Hermia Willemse
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital, PO Box 334, Canberra, ACT 2601 Australia
| | - Linda Groom
- Department of Physiology and Pharmacology, University of Rochester Medical Center, Rochester, NY USA
| | - Marco G Casarotto
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital, PO Box 334, Canberra, ACT 2601 Australia
| | - Philip G Board
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital, PO Box 334, Canberra, ACT 2601 Australia
| | - Nicole A Beard
- Discipline of Biomedical Sciences, Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, ACT 2601 Australia
| | - Robert T Dirksen
- Department of Physiology and Pharmacology, University of Rochester Medical Center, Rochester, NY USA
| | - Angela F Dulhunty
- John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital, PO Box 334, Canberra, ACT 2601 Australia
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13
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Uversky VN. Unreported intrinsic disorder in proteins: Building connections to the literature on IDPs. INTRINSICALLY DISORDERED PROTEINS 2014; 2:e970499. [PMID: 28232880 PMCID: PMC5314882 DOI: 10.4161/21690693.2014.970499] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 09/08/2014] [Indexed: 02/07/2023]
Abstract
This review opens a new series entitled “Unreported intrinsic disorder in proteins.” The goal of this series is to bring attention of researchers to an interesting phenomenon of missed (or overlooked, or ignored, or unreported) disorder. This series serves as a companion to “Digested Disorder” which provides a quarterly review of papers on intrinsically disordered proteins (IDPs) found by standard literature searches. The need for this alternative series results from the observation that there are numerous publications that describe IDPs (or hybrid proteins with ordered and disordered regions) yet fail to recognize many of the key discoveries and publications in the IDP field. By ignoring the body of work on IDPs, such publications often fail to relate their findings to prior discoveries or fail to explore the obvious implications of their work. Thus, the goal of this series is not only to review these very interesting and important papers, but also to point out how each paper relates to the IDP field and show how common tools in the IDP field can readily take the findings in new directions or provide a broader context for the reported findings.
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Affiliation(s)
- Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute; Morsani College of Medicine; University of South Florida; Tampa, FL USA; Institute for Biological Instrumentation; Russian Academy of Sciences; Pushchino, Russia; Biology Department; Faculty of Science; King Abdulaziz University; Jeddah, Kingdom of Saudi Arabia
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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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15
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Amador FJ, Kimlicka L, Stathopulos PB, Gasmi-Seabrook GMC, Maclennan DH, Van Petegem F, Ikura M. Type 2 ryanodine receptor domain A contains a unique and dynamic α-helix that transitions to a β-strand in a mutant linked with a heritable cardiomyopathy. J Mol Biol 2013; 425:4034-46. [PMID: 23978697 DOI: 10.1016/j.jmb.2013.08.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/09/2013] [Accepted: 08/19/2013] [Indexed: 11/18/2022]
Abstract
Ryanodine receptors (RyRs) are large tetrameric calcium (Ca(2+)) release channels found on the sarcoplasmic reticulum that respond to dihydropyridine receptor activity through a direct conformational interaction and/or indirect Ca(2+) sensitivity, propagating sarcoplasmic reticulum luminal Ca(2+) release in the process of excitation-contraction coupling. There are three human RyR subtypes, and several debilitating diseases are linked to heritable mutations in RyR1 and RyR2 including malignant hypothermia, central core disease, catecholaminergic polymorphic ventricular tachycardia (CPVT) and arrhythmogenic right ventricular dysplasia type 2 (ARVD2). Despite the recent appreciation that many disease-associated mutations within the N-terminal RyRABC domains (i.e., residues 1-559) are located in the putative interfaces mediating tetrameric channel assembly, the precise structural and dynamical consequences of the mutations are not well understood. We used solution nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography to examine the effect of ARVD2-associated (i.e., R176Q) and CPVT-associated [i.e., P164S, R169Q and delta exon 3 (Δ3)] mutations on the structure and dynamics of RyR2A. Our solution NMR data exposed a mobile α-helix, unique to type 2; further, this α2 helix rescues the β-strand lost in RyR2A Δ3 but remains dynamic in the hot-spot loop (HS-loop) P164S, R169Q and R176Q mutant proteins. Docking of our X-ray crystal/NMR hybrid structure into the RyR1 cryo-electron microscopy map revealed that this RyR2A α2 helix is in close proximity to dense "columns" projecting toward the channel pore. This is in contrast to the HS-loop mutations that cause structural changes largely localized to the intersubunit interface between adjacent ABC domains. Taken together, our data suggest that ARVD2 and CPVT mutations have at least two distinct structural consequences linked to channel dysfunction: perturbation of the HS-loop (i.e., domain A):domain B intersubunit interface and disruption of the communication between the N-terminal region and the channel domain.
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Affiliation(s)
- Fernando J Amador
- Campbell Family Institute for Cancer Research, Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 1L7
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Plotkin JL, Shen W, Rafalovich I, Sebel LE, Day M, Chan CS, Surmeier DJ. Regulation of dendritic calcium release in striatal spiny projection neurons. J Neurophysiol 2013; 110:2325-36. [PMID: 23966676 DOI: 10.1152/jn.00422.2013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The induction of corticostriatal long-term depression (LTD) in striatal spiny projection neurons (SPNs) requires coactivation of group I metabotropic glutamate receptors (mGluRs) and L-type Ca(2+) channels. This combination leads to the postsynaptic production of endocannabinoids that act presynaptically to reduce glutamate release. Although the necessity of coactivation is agreed upon, why it is necessary in physiologically meaningful settings is not. The studies described here attempt to answer this question by using two-photon laser scanning microscopy and patch-clamp electrophysiology to interrogate the dendritic synapses of SPNs in ex vivo brain slices from transgenic mice. These experiments revealed that postsynaptic action potentials induce robust ryanodine receptor (RYR)-dependent Ca(2+)-induced-Ca(2+) release (CICR) in SPN dendritic spines. Depolarization-induced opening of voltage-gated Ca(2+) channels was necessary for CICR. CICR was more robust in indirect pathway SPNs than in direct pathway SPNs, particularly in distal dendrites. Although it did not increase intracellular Ca(2+) concentration alone, group I mGluR activation enhanced CICR and slowed Ca(2+) clearance, extending the activity-evoked intraspine transient. The mGluR modulation of CICR was sensitive to antagonism of inositol trisphosphate receptors, RYRs, src kinase, and Cav1.3 L-type Ca(2+) channels. Uncaging glutamate at individual spines effectively activated mGluRs and facilitated CICR induced by back-propagating action potentials. Disrupting CICR by antagonizing RYRs prevented the induction of corticostriatal LTD with spike-timing protocols. In contrast, mGluRs had no effect on the induction of long-term potentiation. Taken together, these results make clearer how coactivation of mGluRs and L-type Ca(2+) channels promotes the induction of activity-dependent LTD in SPNs.
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Affiliation(s)
- Joshua L Plotkin
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Amador FJ, Stathopulos PB, Enomoto M, Ikura M. Ryanodine receptor calcium release channels: lessons from structure-function studies. FEBS J 2013; 280:5456-70. [PMID: 23413940 DOI: 10.1111/febs.12194] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/24/2013] [Accepted: 02/04/2013] [Indexed: 11/28/2022]
Abstract
Ryanodine receptors (RyRs) are the largest known ion channels. They are Ca(2+) release channels found primarily on the sarcoplasmic reticulum of myocytes. Several hundred mutations in RyRs are associated with skeletal or cardiomyocyte disease in humans. Many of these mutations can now be mapped onto the high resolution structures of individual RyR domains and on full-length tetrameric cryo-electron microscopy structures. A closely related Ca(2+) release channel, the inositol 1,4,5-trisphospate receptor (IP3 R), shows a conserved structural architecture at the N-terminus, suggesting that both channels evolved from an ancestral unicellular RyR/IP3 R. The functional insights provided by recent structural studies for both channels will aid in the development of rationale treatments for a myriad of Ca(2+)-signaled malignancies.
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Affiliation(s)
- Fernando J Amador
- Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Canada
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18
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Board PG, Menon D. Glutathione transferases, regulators of cellular metabolism and physiology. Biochim Biophys Acta Gen Subj 2012. [PMID: 23201197 DOI: 10.1016/j.bbagen.2012.11.019] [Citation(s) in RCA: 259] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND The cytosolic glutathione transferases (GSTs) comprise a super family of proteins that can be categorized into multiple classes with a mixture of highly specific and overlapping functions. SCOPE OF REVIEW The review covers the genetics, structure and function of the human cytosolic GSTs with particular attention to their emerging roles in cellular metabolism. MAJOR CONCLUSIONS All the catalytically active GSTs contribute to the glutathione conjugation or glutathione dependant-biotransformation of xenobiotics and many catalyze glutathione peroxidase or thiol transferase reactions. GSTs also catalyze glutathione dependent isomerization reactions required for the synthesis of several prostaglandins and steroid hormones and the catabolism of tyrosine. An increasing body of work has implicated several GSTs in the regulation of cell signaling pathways mediated by stress-activated kinases like Jun N-terminal kinase. In addition, some members of the cytosolic GST family have been shown to form ion channels in intracellular membranes and to modulate ryanodine receptor Ca(2+) channels in skeletal and cardiac muscle. GENERAL SIGNIFICANCE In addition to their well established roles in the conjugation and biotransformation of xenobiotics, GSTs have emerged as significant regulators of pathways determining cell proliferation and survival and as regulators of ryanodine receptors that are essential for muscle function. This article is part of a Special Issue entitled Cellular functions of glutathione.
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Affiliation(s)
- Philip G Board
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
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Hernández A, Schiffer TA, Ivarsson N, Cheng AJ, Bruton JD, Lundberg JO, Weitzberg E, Westerblad H. Dietary nitrate increases tetanic [Ca2+]i and contractile force in mouse fast-twitch muscle. J Physiol 2012; 590:3575-83. [PMID: 22687611 DOI: 10.1113/jphysiol.2012.232777] [Citation(s) in RCA: 227] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Dietary inorganic nitrate has profound effects on health and physiological responses to exercise. Here, we examined if nitrate, in doses readily achievable via a normal diet, could improve Ca(2+) handling and contractile function using fast- and slow-twitch skeletal muscles from C57bl/6 male mice given 1 mm sodium nitrate in water for 7 days. Age matched controls were provided water without added nitrate. In fast-twitch muscle fibres dissected from nitrate treated mice, myoplasmic free [Ca(2+)] was significantly greater than in Control fibres at stimulation frequencies from 20 to 150 Hz, which resulted in a major increase in contractile force at ≤ 50 Hz. At 100 Hz stimulation, the rate of force development was ∼35% faster in the nitrate group. These changes in nitrate treated mice were accompanied by increased expression of the Ca(2+) handling proteins calsequestrin 1 and the dihydropyridine receptor. No changes in force or calsequestrin 1 and dihydropyridine receptor expression were measured in slow-twitch muscles. In conclusion, these results show a striking effect of nitrate supplementation on intracellular Ca(2+) handling in fast-twitch muscle resulting in increased force production. A new mechanism is revealed by which nitrate can exert effects on muscle function with applications to performance and a potential therapeutic role in conditions with muscle weakness.
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Affiliation(s)
- Andrés Hernández
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
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20
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Perálvarez-Marín A, Tae H, Board PG, Casarotto MG, Dulhunty AF, Samsó M. 3D Mapping of the SPRY2 domain of ryanodine receptor 1 by single-particle cryo-EM. PLoS One 2011; 6:e25813. [PMID: 21998699 PMCID: PMC3187800 DOI: 10.1371/journal.pone.0025813] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 09/11/2011] [Indexed: 01/26/2023] Open
Abstract
The type 1 skeletal muscle ryanodine receptor (RyR1) is principally responsible for Ca(2+) release from the sarcoplasmic reticulum and for the subsequent muscle contraction. The RyR1 contains three SPRY domains. SPRY domains are generally known to mediate protein-protein interactions, however the location of the three SPRY domains in the 3D structure of the RyR1 is not known. Combining immunolabeling and single-particle cryo-electron microscopy we have mapped the SPRY2 domain (S1085-V1208) in the 3D structure of RyR1 using three different antibodies against the SPRY2 domain. Two obstacles for the image processing procedure; limited amount of data and signal dilution introduced by the multiple orientations of the antibody bound in the tetrameric RyR1, were overcome by modifying the 3D reconstruction scheme. This approach enabled us to ascertain that the three antibodies bind to the same region, to obtain a 3D reconstruction of RyR1 with the antibody bound, and to map SPRY2 to the periphery of the cytoplasmic domain of RyR1. We report here the first 3D localization of a SPRY2 domain in any known RyR isoform.
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Affiliation(s)
- Alex Perálvarez-Marín
- Department of Anesthesia, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Centre d'Estudis Biofísics, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - HanShen Tae
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Philip G. Board
- 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
| | - Angela F. Dulhunty
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Montserrat Samsó
- Department of Anesthesia, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Song DW, Lee JG, Youn HS, Eom SH, Kim DH. Ryanodine receptor assembly: A novel systems biology approach to 3D mapping. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 105:145-61. [DOI: 10.1016/j.pbiomolbio.2010.09.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 09/14/2010] [Accepted: 09/28/2010] [Indexed: 10/19/2022]
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22
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Tae HS, Cui Y, Karunasekara Y, Board PG, Dulhunty AF, Casarotto MG. Cyclization of the intrinsically disordered α1S dihydropyridine receptor II-III loop enhances secondary structure and in vitro function. J Biol Chem 2011; 286:22589-99. [PMID: 21525002 DOI: 10.1074/jbc.m110.205476] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A key component of excitation contraction (EC) coupling in skeletal muscle is the cytoplasmic linker (II-III loop) between the second and third transmembrane repeats of the α(1S) subunit of the dihydropyridine receptor (DHPR). The II-III loop has been previously examined in vitro using a linear II-III loop with unrestrained N- and C-terminal ends. To better reproduce the loop structure in its native environment (tethered to the DHPR transmembrane domains), we have joined the N and C termini using intein-mediated technology. Circular dichroism and NMR spectroscopy revealed a structural shift in the cyclized loop toward a protein with increased α-helical and β-strand structure in a region of the loop implicated in its in vitro function and also in a critical region for EC coupling. The affinity of binding of the II-III loop binding to the SPRY2 domain of the skeletal ryanodine receptor (RyR1) increased 4-fold, and its ability to activate RyR1 channels in lipid bilayers was enhanced 3-fold by cyclization. These functional changes were predicted consequences of the structural enhancement. We suggest that tethering the N and C termini stabilized secondary structural elements in the DHPR II-III loop and may reflect structural and dynamic characteristics of the loop that are inherent in EC coupling.
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Affiliation(s)
- Han-Shen Tae
- John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra, Australian Capital Territory 2601, Australia
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23
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Tae H, Wei L, Willemse H, Mirza S, Gallant EM, Board PG, Dirksen RT, Casarotto MG, Dulhunty A. The elusive role of the SPRY2 domain in RyR1. Channels (Austin) 2011; 5:148-60. [PMID: 21239886 DOI: 10.4161/chan.5.2.14407] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The second of three SPRY domains (SPRY2, S1085 -V1208) located in the skeletal muscle ryanodine receptor (RyR1) is contained within regions of RyR1 that influence EC coupling and bind to imperatoxin A, a toxin probe of RyR1 channel gating. We examined the binding of the F loop (P1107-A1121) in SPRY2 to the ASI/basic region in RyR1 (T3471-G3500, containing both alternatively spliced (ASI) residues and neighboring basic amino acids). We then investigated the possible influence of this interaction on excitation contraction (EC) coupling. A peptide with the F loop sequence and an antibody to the SPRY2 domain each enhanced RyR1 activity at low concentrations and inhibited at higher concentrations. A peptide containing the ASI/basic sequence bound to SPRY2 and binding decreased ~10-fold following mutation or structural disruption of the basic residues. Binding was abolished by mutation of three critical acidic F loop residues. Together these results suggest that the ASI/basic and SPRY2 domains interact in an F loop regulatory module. Although a region that includes the SPRY2 domain influences EC coupling, as does the ASI/basic region, Ca2+ release during ligand- and depolarization-induced RyR1 activation were not altered by mutation of the three critical F loop residues following expression of mutant RyR1 in RyR1-null myotubes. Therefore the electrostatic regulatory interaction between the SPRY2 F loop residues (that bind to imperatoxin A) and the ASI/basic residues of RyR1 does not influence bi-directional DHPR-RyR1 signaling during skeletal EC coupling, possibly because the interaction is interrupted by the influence of factors present in intact muscle cells.
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Affiliation(s)
- HanShen Tae
- Howard Florey Institute, Parkville, Victoria, Australia
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Dulhunty AF, Hewawasam R, Liu D, Casarotto MG, Board PG. Regulation of the cardiac muscle ryanodine receptor by glutathione transferases. Drug Metab Rev 2011; 43:236-52. [DOI: 10.3109/03602532.2010.549134] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Affiliation(s)
- Angela Dulhunty
- John Curtin School of Medical Research, Canberra City, ACT, Australia.
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Homer and the ryanodine receptor. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:91-102. [PMID: 19513708 DOI: 10.1007/s00249-009-0494-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 10/20/2022]
Abstract
Homer proteins have recently been identified as novel high-affinity ligands that modulate ryanodine receptor (RyR) Ca(2+) release channels in heart and skeletal muscle, through an EVH1 domain which binds to proline-rich regions in target proteins. Many Homer proteins can also self-associate through a coiled-coil domain that allows their multimerisation. In other tissues, especially neurons, Homer anchors proteins embedded in the surface membrane to the Ca(2+) release channel in the endoplasmic reticulum and can anchor membrane or cytosolic proteins to the cytoskeleton. Although this anchoring aspect of Homer function has not been extensively investigated in muscle, there are consensus sequences for Homer binding in the RyR and on many of the proteins that it interacts with in the massive RyR ion channel complex. In this review we explore the potential of Homer to contribute to a variety of cell processes in muscle and neurons that also involve RyR channels.
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Ubiquitous SPRY domains and their role in the skeletal type ryanodine receptor. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:51-9. [DOI: 10.1007/s00249-009-0455-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 03/28/2009] [Accepted: 04/07/2009] [Indexed: 10/20/2022]
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28
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Tae HS, Norris NC, Cui Y, Karunasekara Y, Board PG, Dulhunty AF, Casarotto MG. MOLECULAR RECOGNITION OF THE DISORDERED DIHYDROPYRIDINE RECEPTOR II-III LOOP BY A CONSERVED SPRY DOMAIN OF THE TYPE 1 RYANODINE RECEPTOR. Clin Exp Pharmacol Physiol 2009; 36:346-9. [DOI: 10.1111/j.1440-1681.2008.05130.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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29
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Calcium and the role of motoneuronal doublets in skeletal muscle control. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 38:159-73. [DOI: 10.1007/s00249-008-0364-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 08/05/2008] [Accepted: 08/05/2008] [Indexed: 11/26/2022]
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A dihydropyridine receptor alpha1s loop region critical for skeletal muscle contraction is intrinsically unstructured and binds to a SPRY domain of the type 1 ryanodine receptor. Int J Biochem Cell Biol 2008; 41:677-86. [PMID: 18761102 DOI: 10.1016/j.biocel.2008.08.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 07/21/2008] [Accepted: 08/04/2008] [Indexed: 12/15/2022]
Abstract
The II-III loop of the dihydropyridine receptor (DHPR) alpha(1s) subunit is a modulator of the ryanodine receptor (RyR1) Ca(2+) release channel in vitro and is essential for skeletal muscle contraction in vivo. Despite its importance, the structure of this loop has not been reported. We have investigated its structure using a suite of NMR techniques which revealed that the DHPR II-III loop is an intrinsically unstructured protein (IUP) and as such belongs to a burgeoning structural class of functionally important proteins. The loop does not possess a stable tertiary fold: it is highly flexible, with a strong N-terminal helix followed by nascent helical/turn elements and unstructured segments. Its residual structure is loosely globular with the N and C termini in close proximity. The unstructured nature of the II-III loop may allow it to easily modify its interaction with RyR1 following a surface action potential and thus initiate rapid Ca(2+) release and contraction. The in vitro binding partner for the II-III was investigated. The II-III loop interacts with the second of three structurally distinct SPRY domains in RyR1, whose function is unknown. This interaction occurs through two preformed N-terminal alpha-helical regions and a C-terminal hydrophobic element. The A peptide corresponding to the helical N-terminal region is a common probe of RyR function and binds to the same SPRY domain as the full II-III loop. Thus the second SPRY domain is an in vitro binding site for the II-III loop. The possible in vivo role of this region is discussed.
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Rossi D, Barone V, Giacomello E, Cusimano V, Sorrentino V. The sarcoplasmic reticulum: an organized patchwork of specialized domains. Traffic 2008; 9:1044-9. [PMID: 18266914 DOI: 10.1111/j.1600-0854.2008.00717.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The sarcoplasmic reticulum (SR) of skeletal muscle cells is a convoluted structure composed of a variety of tubules and cisternae, which share a continuous lumen delimited by a single continuous membrane, branching to form a network that surrounds each myofibril. In this network, some specific domains basically represented by the longitudinal SR and the junctional SR can be distinguished. These domains are mainly dedicated to Ca(2+) homeostasis in relation to regulation of muscle contraction, with the longitudinal SR representing the sites of Ca(2+) uptake and storage and the junctional SR representing the sites of Ca(2+) release. To perform its functions, the SR takes contact with other cellular elements, the sarcolemma, the contractile apparatus and the mitochondria, giving rise to a number of interactions, most of which are still to be defined at the molecular level. This review will describe some of the most recent advancements in understanding the organization of this complex network and its specific domains. Furthermore, we shall address initial evidence on how SR proteins are retained at distinct SR domains.
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Affiliation(s)
- Daniela Rossi
- Molecular Medicine Section, Department of Neuroscience and Interuniversitary Institute of Myology, University of Siena, 53100 Siena, Italy
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Monnier N, Marty I, Faure J, Castiglioni C, Desnuelle C, Sacconi S, Estournet B, Ferreiro A, Romero N, Laquerriere A, Lazaro L, Martin JJ, Morava E, Rossi A, Van der Kooi A, de Visser M, Verschuuren C, Lunardi J. Null mutations causing depletion of the type 1 ryanodine receptor (RYR1) are commonly associated with recessive structural congenital myopathies with cores. Hum Mutat 2008; 29:670-8. [DOI: 10.1002/humu.20696] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bagnaresi P, Rodrigues MT, Garcia CRS. Calcium signaling in lizard red blood cells. Comp Biochem Physiol A Mol Integr Physiol 2007; 147:779-787. [PMID: 17095273 DOI: 10.1016/j.cbpa.2006.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 09/21/2006] [Accepted: 09/25/2006] [Indexed: 11/16/2022]
Abstract
The ion calcium is a ubiquitous second messenger, present in all eukaryotic cells. It modulates a vast number of cellular events, such as cell division and differentiation, fertilization, cell volume, decodification of external stimuli. To process this variety of information, the cells display a number of calcium pools, which are capable of mobilization for signaling purposes. Here we review the calcium signaling on lizards red blood cells, an interesting model that has been receiving an increasing notice recently. These cells possess a complex machinery to regulate calcium, and display calcium responses to extracellular agonists. Interestingly, the pattern of calcium handling and response are divergent in different lizard families, which enforces the morphological data to their phylogenetic classification, and suggest the radiation of different calcium signaling models in lizards evolution.
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Affiliation(s)
- Piero Bagnaresi
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Miguel T Rodrigues
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Célia R S Garcia
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
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Chiang W, Byrem T, Zhang H, Strasburg G. Binding property of avian skeletal muscle ryanodine receptor isoforms with dihydropyridine receptor and calmodulin. J Muscle Res Cell Motil 2007; 28:59-66. [PMID: 17505897 DOI: 10.1007/s10974-007-9106-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 04/18/2007] [Indexed: 10/23/2022]
Abstract
Ca(2+) release during excitation-contraction coupling in avian skeletal muscle is controlled by two ryanodine receptor isoforms, alphaRYR and betaRYR. Two other proteins, dihydropyridine receptor (DHPR) and calmodulin (CaM), have been shown to play important roles in regulating the RYR channel activity. In the current study, we measured the protein contents of DHPR and RYR in turkey skeletal muscle and obtained a ratio of 1:1 between DHPR and alphaRYR which suggests that only a subpopulation of alphaRYR is interacting with DHPR. Two CaM derivatives, the photoactivable crosslinking probe [(125)I]-Bz-CaM and metabolically labeled probe [(35)S]CaM, were used to study the interaction between CaM and RYR isoforms in turkey skeletal muscle. The alphaRYR and betaRYR displayed a marked difference in their CaM binding behavior. At a Ca(2+) concentration of 200 microM, CaM bound to both isoforms at a ratio of one CaM molecule per one RYR subunit. At a Ca(2+) concentration of <10 nM, CaM bound primarily to alphaRYR and the binding affinity was significantly lower than that at micromolar level of Ca(2+) concentration. Cloning and sequencing of putative CaM binding sites in alphaRYR and betaRYR suggests that differences in primary structures of the CaM binding sites of each RYR isoform may contribute to the differential CaM binding behavior of alphaRYR and betaRYR.
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Affiliation(s)
- Wen Chiang
- Department of Food Science and Human Nutrition, Michigan State University, R3365 Anthony Hall, East Lansing, MI 48824, USA.
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Dulhunty AF, Beard NA, Pouliquin P, Casarotto MG. Agonists and antagonists of the cardiac ryanodine receptor: Potential therapeutic agents? Pharmacol Ther 2007; 113:247-63. [PMID: 17055586 DOI: 10.1016/j.pharmthera.2006.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Accepted: 08/16/2006] [Indexed: 10/24/2022]
Abstract
This review addresses the potential use of the intracellular ryanodine receptor (RyR) Ca(2+) release channel as a therapeutic target in heart disease. Heart disease encompasses a wide range of conditions with the major contributors to mortality and morbidity being ischaemic heart disease and heart failure (HF). In addition there are many rare, but devastating conditions, some of which are either genetically linked to the RyR and its regulatory proteins or involve drug-induced modification of the proteins. The defects in Ca(2+) signalling vary with the nature of the heart disease and the stage in its progress and therefore specific corrections require different modifications of Ca(2+) signalling. Compounds that activate the RyR are potential inotropic agents to increase the Ca(2+) transient and strength of contraction. Compounds that reduce RyR activity are potentially useful in conditions where excess RyR activity initiates arrhythmias, or depletes the Ca(2+) store, as in end stage HF. It has recently been discovered that the cardio-protective action of the drug JTV519 can be attributed partly to its ability to stabilise the interaction between the RyR and the 12.6 kDa binding protein for the commonly used immunosuppressive drug FK506 (FKBP12.6, known as tacrolimus). This has established the credibility of the RyR as a therapeutic target. We explore the possibility that mutations causing the rare RyR-linked arrhythmias will open the door to identification of novel RyR-based therapeutic agents. The use of regulatory binding sites within the RyR complex or on its associated proteins as templates for drug design is discussed.
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Affiliation(s)
- Angela F Dulhunty
- Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, P.O. Box 334, ACT, 2601, Australia
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Laver DR. Regulation of ryanodine receptors from skeletal and cardiac muscle during rest and excitation. Clin Exp Pharmacol Physiol 2007; 33:1107-13. [PMID: 17042923 DOI: 10.1111/j.1440-1681.2006.04500.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
1. In muscle, intracellular calcium concentration, hence skeletal muscle force and cardiac output, is regulated by uptake and release of calcium from the sarcoplasmic reticulum (SR). The ryanodine receptor (RyR) forms the calcium release channel in the SR. 2. Calcium release through RyRs is modulated by a wide variety of endogenous molecules, including small diffusible ligands such as ATP, Ca2+ and Mg2+. The regulation of RyR channels by ATP, Ca2+ and Mg2+ is a complex interplay of several regulatory mechanisms, which are still being unravelled. Consequently, it is not clearly known how RyRs are regulated in resting muscle and during contraction. 3. The present paper reviews factors controlling the activity of RyRs in skeletal and cardiac muscle with an emphasis on mechanistic insights derived from single channel recording methods. 4. In addition, the nature of dihydropyridine receptor (DHPR) control of RyRs in skeletal muscle derived from experiments with peptide fragments of the DHPR II-III loop is reviewed. 5. Finally, recent experiments on coupled RyRs in lipid bilayers and their potential for resolving the elusive mechanisms controlling calcium release during cardiac contraction are discussed.
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Affiliation(s)
- D R Laver
- School of Biomedical Sciences, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia.
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Katritsis DG, Sotiropoulou P, Giazitzoglou E, Karvouni E, Papamichail M. Electrophysiological effects of intracoronary transplantation of autologous mesenchymal and endothelial progenitor cells. Europace 2007; 9:167-71. [PMID: 17272327 DOI: 10.1093/europace/eul184] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
AIMS Autologous stem cell transplantation has been successfully used for repair of infarcted myocardium, but concerns have been raised regarding its pro-arrhythmic potential. This study aimed at using electrophysiological assessment, and the monitoring and data storage capacity of implanted cardioverter defibrillators (ICDs), in order to evaluate the possible proarrhythmic potential of stem cell transplantation. METHODS Five patients with a history of previous anteroseptal myocardial infarction and an implanted ICD for ventricular arrhythmias underwent intracoronary transplantation of autologous bone marrow-derived and culture-expanded mesenchymal stem cells in combination with endothelial progenitors. RESULTS There was evidence of myocardial repair in three patients in whom segmental left ventricular wall motion improvement was detected on stress echocardiography. Before stem cell transplantation, clinical non-sustained ventricular tachycardia and inducible monomorphic ventricular tachycardia, or ventricular flutter at electrophysiology study were demonstrated in all patients. At 16-36 months follow-up, interrogation of the ICD failed to detect sustained or non-sustained ventricular arrhythmia in any patient. At repeat electrophysiology study, sustained ventricular arrhythmia was induced in two patients. CONCLUSION Intracoronary transplantation of autologous mesenchymal and endothelial progenitor cells does not appear to be arrhythmogenic in humans. Further studies are needed on this important clinical issue.
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Joshi I, Taylor CP. Pregabalin action at a model synapse: Binding to presynaptic calcium channel α2-δ subunit reduces neurotransmission in mice. Eur J Pharmacol 2006; 553:82-8. [PMID: 17064682 DOI: 10.1016/j.ejphar.2006.09.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 09/06/2006] [Accepted: 09/08/2006] [Indexed: 11/18/2022]
Abstract
Pregabalin, ((S)-3-(aminomethyl)-5-methylhexanoic acid, also known as (S)-3-isobutyl GABA, Lyricatrade mark) is approved for treatment of certain types of peripheral neuropathic pain and as an adjunctive therapy for partial seizures of epilepsy both the EU and the USA and also for generalized anxiety disorder in the EU. Though pregabalin binds selectively to the alpha(2)-delta (alpha(2)-delta) auxiliary subunit of voltage-gated calcium channels, the cellular details of pregabalin action are unclear. The high density of alpha(2)-delta in skeletal muscle fibers raises the question of whether pregabalin alters excitation-contraction coupling. We used the mouse soleus neuromuscular junction from mice containing an artificially mutated alpha(2)-delta Type 1 protein (R217A) as a model to examine the effect of pregabalin. Pregabalin reduced nerve-evoked muscle contractions by 16% at a clinically relevant concentration of 10 muM in wildtype mice. When acetylcholine receptors were blocked with curare, pregabalin had no effect on contraction from direct stimulation of muscle, suggesting a lack of drug effects on contraction coupling. Our data are consistent with pregabalin having no effect on striated muscle L-type calcium channel function. However, in mice expressing mutant (R217A) alpha(2)-delta Type 1, there was no significant effect of pregabalin on nerve-evoked muscle contraction. We propose that pregabalin reduces presynaptic neurotransmitter release without altering postsynaptic receptors or contraction coupling and that these effects require high affinity binding to alpha(2)-delta Type 1 auxiliary subunit of presynaptic voltage-gated calcium channels.
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Affiliation(s)
- Indu Joshi
- Department CNS Biology, Pfizer Global R&D, 2800 Plymouth Road, Ann Arbor, MI 48105, USA
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Casarotto MG, Cui Y, Karunasekara Y, Harvey PJ, Norris N, Board PG, Dulhunty AF. STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF INTERACTIONS BETWEEN THE DIHYDROPYRIDINE RECEPTOR II?III LOOP AND THE RYANODINE RECEPTOR. Clin Exp Pharmacol Physiol 2006; 33:1114-7. [PMID: 17042924 DOI: 10.1111/j.1440-1681.2006.04501.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. Excitation-contraction coupling in skeletal muscle is dependent on a physical interaction between the dihydropyridine receptor (DHPR) and the ryanodine receptor (RyR). 2. A number of peptides derived from the II-III loop region of the DHPR have been shown to be functionally active in stimulating the release of calcium via RyR channels. Their function has been found to correlate with the presence of a basic helical region located at the N-terminus of the II-III loop. 3. The entire recombinant skeletal DHPR II-III loop is an efficient activator of RyR1 and RyR2. 4. The skeletal DHPR II-III loop is comprised of a series of a-helices, but its tertiary structure has been determined to be unstructured and flexible. 5. Fluorescence quenching experiments have been used to identify and measure the binding affinity of the II-III loop with fragments of the RyR.
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Affiliation(s)
- Marco G Casarotto
- Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia.
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40
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Yang SN, Berggren PO. The role of voltage-gated calcium channels in pancreatic beta-cell physiology and pathophysiology. Endocr Rev 2006; 27:621-76. [PMID: 16868246 DOI: 10.1210/er.2005-0888] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Voltage-gated calcium (CaV) channels are ubiquitously expressed in various cell types throughout the body. In principle, the molecular identity, biophysical profile, and pharmacological property of CaV channels are independent of the cell type where they reside, whereas these channels execute unique functions in different cell types, such as muscle contraction, neurotransmitter release, and hormone secretion. At least six CaValpha1 subunits, including CaV1.2, CaV1.3, CaV2.1, CaV2.2, CaV2.3, and CaV3.1, have been identified in pancreatic beta-cells. These pore-forming subunits complex with certain auxiliary subunits to conduct L-, P/Q-, N-, R-, and T-type CaV currents, respectively. beta-Cell CaV channels take center stage in insulin secretion and play an important role in beta-cell physiology and pathophysiology. CaV3 channels become expressed in diabetes-prone mouse beta-cells. Point mutation in the human CaV1.2 gene results in excessive insulin secretion. Trinucleotide expansion in the human CaV1.3 and CaV2.1 gene is revealed in a subgroup of patients with type 2 diabetes. beta-Cell CaV channels are regulated by a wide range of mechanisms, either shared by other cell types or specific to beta-cells, to always guarantee a satisfactory concentration of Ca2+. Inappropriate regulation of beta-cell CaV channels causes beta-cell dysfunction and even death manifested in both type 1 and type 2 diabetes. This review summarizes current knowledge of CaV channels in beta-cell physiology and pathophysiology.
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Affiliation(s)
- Shao-Nian Yang
- The Rolf Luft Research Center for Diabetes and Endocrinology L1:03, Karolinska University Hospital Solna, SE-171 76 Stockholm, Sweden.
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41
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Jurkat-Rott K, Fauler M, Lehmann-Horn F. Ion channels and ion transporters of the transverse tubular system of skeletal muscle. J Muscle Res Cell Motil 2006; 27:275-90. [PMID: 16933023 DOI: 10.1007/s10974-006-9088-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Accepted: 07/05/2006] [Indexed: 11/27/2022]
Abstract
This review focuses on the electrical properties of the transverse (T) tubular membrane of skeletal muscle, with reference to the contribution of the T-tubular system (TTS) to the surface action potential, the radial spread of excitation and its role in excitation-contraction coupling. Particularly, the most important ion channels and ion transporters that enable proper depolarization and repolarization of the T-tubular membrane are described. Since propagation of excitation along the TTS into the depth of the fibers is a delicate balance between excitatory and inhibitory currents, the composition of channels and transporters is specific to the TTS and different from the surface membrane. The TTS normally enables the radial spread of excitation and the signal transfer to the sarcoplasmic reticulum to release calcium that activates the contractile apparatus. However, due to its structure, even slight shifts of ions may alter its volume, Nernstian potentials, ion permeabilities, and consequently T-tubular membrane potential and excitability.
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42
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Dulhunty AF, Beard NA, Pouliquin P, Kimura T. Novel regulators of RyR Ca2+ release channels: insight into molecular changes in genetically-linked myopathies. J Muscle Res Cell Motil 2006; 27:351-65. [PMID: 16909197 DOI: 10.1007/s10974-006-9086-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 06/26/2006] [Indexed: 10/24/2022]
Abstract
There are many mutations in the ryanodine receptor (RyR) Ca2+ release channel that are implicated in skeletal muscle disorders and cardiac arrhythmias. More than 80 mutations in the skeletal RyR1 have been identified and linked to malignant hyperthermia, central core disease or multi-minicore disease, while more than 40 mutations in the cardiac RyR2 lead to ventricular arrhythmias and sudden cardiac death in patients with structurally normal hearts. These RyR mutations cause diverse changes in RyR activity which either excessively activate or block the channel in a manner that disrupts Ca2+ signalling in the muscle fibres. In a different myopathy, myotonic dystrophy (DM), a juvenile isoform of the skeletal RyR is preferentially expressed in adults. There are two regions of RyR1 that are variably spiced and developmentally regulated (ASI and ASII). The juvenile isoform (ASI(-)) is less active than the adult isoform (ASI(+)) and its over-expression in adults with DM may contribute to functional changes. Finally, mutations in an important regulator of the RyR, the Ca2+ binding protein calsequestrin (CSQ), have been linked to a disruption of Ca2+ homeostasis in cardiac myocytes that results in arrhythmias. We discuss evidence supporting the hypothesis that mutations in each of these situations alter protein/protein interactions within the RyR complex or between the RyR and its associated proteins. The disruption of these protein-protein interactions can lead either to excess Ca2+ release or reduced Ca2+ release and thus to abnormal Ca2+ homeostasis. Much of the evidence for disruption of protein-protein interactions has been provided by the actions of a group of novel RyR regulators, domain peptides with sequences that correspond to sequences within the RyR and which compete with the endogenous residues for their interaction sites.
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Affiliation(s)
- A F Dulhunty
- Division of Molecular Bioscience, JCSMR and RSC, ANU, Canberra, ACT, 2601, Australia.
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43
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Pouliquin P, Pace SM, Curtis SM, Harvey PJ, Gallant EM, Zorzato F, Casarotto MG, Dulhunty AF. Effects of an alpha-helical ryanodine receptor C-terminal tail peptide on ryanodine receptor activity: modulation by Homer. Int J Biochem Cell Biol 2006; 38:1700-15. [PMID: 16725367 DOI: 10.1016/j.biocel.2006.03.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 03/22/2006] [Accepted: 03/29/2006] [Indexed: 11/30/2022]
Abstract
We have determined the structure of a domain peptide corresponding to the extreme 19 C-terminal residues of the ryanodine receptor Ca2+ release channel. We examined functional interactions between the peptide and the channel, in the absence and in the presence of the regulatory protein Homer. The peptide was partly alpha-helical and structurally homologous to the C-terminal end of the T1 domain of voltage-gated K+ channels. The peptide (0.1-10 microM) inhibited skeletal ryanodine receptor channels when the cytoplasmic Ca2+ concentration was 1 microM; but with 10 microM cytoplasmic Ca2+, skeletal ryanodine receptors were activated by < or = 1.0 microM peptide and inhibited by 10 microM peptide. Cardiac ryanodine receptors on the other hand were inhibited by all peptide concentrations, at both Ca2+ concentrations. When channels did open in the presence of the peptide, they were more likely to open to substate levels. The inhibition and increased fraction of openings to subconductance levels suggested that the domain peptide might destabilise inter-domain interactions that involve the C-terminal tail. We found that Homer 1b not only interacts with the channels, but reduces the inhibitory action of the C-terminal tail peptide, perhaps by stabilizing inter-domain interactions and preventing their disruption.
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Affiliation(s)
- Pierre Pouliquin
- Division of Molecular Bioscience, JCSMR and RSC, ANU, Canberra, ACT 2601, Australia
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44
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Dulhunty AF, Pouliquin P, Coggan M, Gage PW, Board PG. A recently identified member of the glutathione transferase structural family modifies cardiac RyR2 substate activity, coupled gating and activation by Ca2+ and ATP. Biochem J 2005; 390:333-43. [PMID: 15916532 PMCID: PMC1184587 DOI: 10.1042/bj20042113] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The recently discovered CLIC-2 protein (where CLIC stands for chloride intracellular channel), which belongs to the ubiquitous glutathione transferase structural family and is expressed in the myocardium, is a regulator of native cardiac RyR2 (ryanodine receptor 2) channels. Here we show that recombinant CLIC-2 increases [3H]ryanodine binding to native and purified RyR channels, enhances substate activity in individual channels, increases the number of rare coupled gating events between associated RyRs, and reduces activation of the channels by their primary endogenous cytoplasmic ligands, ATP and Ca2+. CLIC-2 (0.2-10 microM) added to the cytoplasmic side of RyR2 channels in lipid bilayers depressed activity in a reversible, voltage-independent, manner in the presence of activating (10-100 microM) or sub-activating (100 nM) cytoplasmic Ca2+ concentrations. Although the number of channel openings to all levels was reduced, the fraction and duration of openings to substate levels were increased after exposure to CLIC-2. CLIC-2 reduced increases in activity induced by ATP or adenosine 5'-[beta,gamma-imido]triphosphate. Depression of channel activity by CLIC-2 was greater in the presence of 100 microM cytoplasmic Ca2+ than with 100 nM or 10 microM Ca2+. Further, CLIC-2 prevented the usual approximately 50-fold increase in activity when the cytoplasmic Ca2+ concentration was increased from 100 nM to 100 microM. The results show that CLIC-2 interacts with the RyR protein by a mechanism that does not require oxidation, but is influenced by a conserved Cys residue at position 30. CLIC-2 is one of only a few cytosolic inhibitors of cardiac RyR2 channels, and may suppress their activity during diastole and during stress. CLIC-2 provides a unique probe for substate activity, coupled gating and ligand-induced activation of cardiac RyR channels.
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Affiliation(s)
- Angela F Dulhunty
- Division of Molecular Bioscience, John Curtin School of Medical Research, P.O. Box 334, Canberra, ACT 2601, Australia.
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45
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Divet A, Paesante S, Bleunven C, Anderson A, Treves S, Zorzato F. Novel sarco(endo)plasmic reticulum proteins and calcium homeostasis in striated muscles. J Muscle Res Cell Motil 2005; 26:7-12. [PMID: 16096683 DOI: 10.1007/s10974-005-9001-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Revised: 06/09/2005] [Accepted: 06/17/2005] [Indexed: 10/25/2022]
Abstract
The impact of calcium signaling on many cellular functions is reflected by the tight regulation of the intracellular Ca(2+) concentration that is ensured by diverse pumps, channels, transporters and Ca(2+) binding proteins. In this review, we present recently identified novel sarco(endo)plasmic reticulum proteins that may have a potential involvement in the regulation of Ca(2+) homeostasis in striated muscles.
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Affiliation(s)
- A Divet
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, University of Ferrara, Italy
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46
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Woods CE, Novo D, DiFranco M, Capote J, Vergara JL. Propagation in the transverse tubular system and voltage dependence of calcium release in normal and mdx mouse muscle fibres. J Physiol 2005; 568:867-80. [PMID: 16123111 PMCID: PMC1464167 DOI: 10.1113/jphysiol.2005.089318] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Using a two-microelectrode voltage clamp technique, we investigated possible mechanisms underlying the impaired excitation-contraction coupling in skeletal muscle fibres of the mdx mouse, a model of the human disease Duchenne muscular dystrophy. We evaluated the role of the transverse tubular system (T-system) by using the potentiometric indicator di-8 ANEPPS, and that of the sarcoplasmic reticulum (SR) Ca2+ release by measuring Ca2+ transients with a low affinity indicator in the presence of high EGTA concentrations under voltage clamp conditions. We observed minimal differences in the T-system structure and the T-system electrical propagation was not different between normal and mdx mice. Whereas the maximum Ca2+ release elicited by voltage pulses was reduced by approximately 67% in mdx fibres, in agreement with previous results obtained using AP stimulation, the voltage dependence of SR Ca2+ release was identical to that seen in normal fibres. Taken together, our data suggest that the intrinsic ability of the sarcoplasmic reticulum to release Ca2+ may be altered in the mdx mouse.
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Affiliation(s)
- Christopher E Woods
- Department of Physiology, UCLA School of Medicine, Los Angeles, CA 90095, USA
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47
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Dulhunty AF, Karunasekara Y, Curtis SM, Harvey PJ, Board PG, Casarotto MG. The recombinant dihydropyridine receptor II-III loop and partly structured 'C' region peptides modify cardiac ryanodine receptor activity. Biochem J 2005; 385:803-13. [PMID: 15511220 PMCID: PMC1134757 DOI: 10.1042/bj20041152] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A physical association between the II-III loop of the DHPR (dihydropryidine receptor) and the RyR (ryanodine receptor) is essential for excitation-contraction coupling in skeletal, but not cardiac, muscle. However, peptides corresponding to a part of the II-III loop interact with the cardiac RyR2 suggesting the possibility of a physical coupling between the proteins. Whether the full II-III loop and its functionally important 'C' region (cardiac DHPR residues 855-891 or skeletal 724-760) interact with cardiac RyR2 is not known and is examined in the present study. Both the cardiac DHPR II-III loop (CDCL) and cardiac peptide (C(c)) activated RyR2 channels at concentrations >10 nM. The skeletal DHPR II-III loop (SDCL) activated channels at < or =100 nM and weakly inhibited at > or =1 microM. In contrast, skeletal peptide (C(s)) inhibited channels at all concentrations when added alone, or was ineffective if added in the presence of C(c). Ca2+-induced Ca2+ release from cardiac sarcoplasmic reticulum was enhanced by CDCL, SDCL and the C peptides. The results indicate that the interaction between the II-III loop and RyR2 depends critically on the 'A' region (skeletal DHPR residues 671-690 or cardiac 793-812) and also involves the C region. Structure analysis indicated that (i) both C(s) and C(c) are random coil at room temperature, but, at 5 degrees C, have partial helical regions in their N-terminal and central parts, and (ii) secondary-structure profiles for CDCL and SDCL are similar. The data provide novel evidence that the DHPR II-III loop and its C region interact with cardiac RyR2, and that the ability to interact is not isoform-specific.
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Affiliation(s)
- Angela F Dulhunty
- Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra, ACT 2601, Australia.
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Dulhunty AF, Cengia L, Young J, Pace SM, Harvey PJ, Lamb GD, Chan YN, Wimmer N, Toth I, Casarotto MG. Functional implications of modifying RyR-activating peptides for membrane permeability. Br J Pharmacol 2005; 144:743-54. [PMID: 15778698 PMCID: PMC1576055 DOI: 10.1038/sj.bjp.0705981] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Our aim was to determine whether lipoamino acid conjugation of peptides that are high-affinity activators of ryanodine receptor (RyR) channels would (a) render the peptides membrane permeable, (b) alter their structure or (a) reduce their activity. The peptides correspond to the A region of the II-III loop of the skeletal dihydropyridine receptor. 2. The lipoamino acid conjugation increased the apparent permeability of the peptide across the Caco-2 cell monolayer by up to approximately 20-fold. 3. Nuclear magnetic resonance showed that the alpha-helical structure of critical basic residues, required for optimal activation of RyRs, was retained after conjugation. 4. The conjugated peptides were more effective in enhancing resting Ca2+ release, Ca2+-induced Ca2+ release and caffeine-induced Ca2+ release from isolated sarcoplasmic reticulum (SR) than their unconjugated counterparts, and significantly enhanced caffeine-induced Ca2+ release from mechanically skinned extensor digitorum longus (EDL) fibres. 5. The effect of both conjugated and unconjugated peptides on Ca2+ release from skeletal SR was 30-fold greater than their effect on either cardiac Ca2+ release or on the Ca2+ Mg2+ ATPase. 6. A small and very low affinity effect of the peptide in slowing Ca2+ uptake by the Ca2+, Mg2+ ATPase was exacerbated by lipoamino acid conjugation in both isolated SR and in skinned EDL fibres. 7. The results show that lipoamino acid conjugation of A region peptides increases their membrane permeability without impairing their structure or efficacy in activating skeletal and cardiac RyRs.
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Affiliation(s)
- Angela F Dulhunty
- Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra, ACT 2601, Australia.
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49
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Kimura T, Nakamori M, Lueck JD, Pouliquin P, Aoike F, Fujimura H, Dirksen RT, Takahashi MP, Dulhunty AF, Sakoda S. Altered mRNA splicing of the skeletal muscle ryanodine receptor and sarcoplasmic/endoplasmic reticulum Ca2+-ATPase in myotonic dystrophy type 1. Hum Mol Genet 2005; 14:2189-200. [PMID: 15972723 DOI: 10.1093/hmg/ddi223] [Citation(s) in RCA: 195] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a debilitating multisystemic disorder caused by a CTG repeat expansion in the DMPK gene. Aberrant splicing of several genes has been reported to contribute to some symptoms of DM1, but the cause of muscle weakness in DM1 and elevated Ca2+ concentrations in cultured DM muscle cells is unknown. Here, we investigated the alternative splicing of mRNAs of two major proteins of the sarcoplasmic reticulum, the ryanodine receptor 1 (RyR1) and sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) 1 or 2. The fetal variants, ASI(-) of RyR1 which lacks residue 3481-3485, and SERCA1b which differs at the C-terminal were significantly increased in skeletal muscles from DM1 patients and the transgenic mouse model of DM1 (HSA(LR)). In addition, a novel variant of SERCA2 was significantly decreased in DM1 patients. The total amount of mRNA for RyR1, SERCA1 and SERCA2 in DM1 and the expression levels of their proteins in HSA(LR) mice were not significantly different. However, heterologous expression of ASI(-) in cultured cells showed decreased affinity for [3H]ryanodine but similar Ca2+ dependency, and decreased channel activity in single-channel recording when compared with wild-type (WT) RyR1. In support of this, RyR1-knockout myotubes expressing ASI(-) exhibited a decreased incidence of Ca2+ oscillations during caffeine exposure compared with that observed for myotubes expressing WT-RyR1. We suggest that aberrant splicing of RyR1 and SERCA1 mRNAs might contribute to impaired Ca2+ homeostasis in DM1 muscle.
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Affiliation(s)
- Takashi Kimura
- Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra ACT 2601, Australia
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Cui Y, Karunasekara Y, Harvey PJ, Board PG, Dulhunty AF, Casarotto MG. 1H, 13C and 15N assignments for the II-III loop region of the skeletal dyhydropyridine receptor. JOURNAL OF BIOMOLECULAR NMR 2005; 32:89-90. [PMID: 16041487 DOI: 10.1007/s10858-005-3038-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Accepted: 02/14/2005] [Indexed: 05/03/2023]
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