1
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Patel S, Zissimopoulos S, Marchant JS. Endo-Lysosomal Two-Pore Channels and Their Protein Partners. Handb Exp Pharmacol 2023; 278:199-214. [PMID: 35902438 DOI: 10.1007/164_2022_601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Two-pore channels are ion channels expressed on acidic organelles such as the various vesicles that constitute the endo-lysosomal system. They are permeable to Ca2+ and Na+ and activated by the second messenger NAADP as well as the phosphoinositide, PI(3,5)P2 and/or voltage. Here, we review the proteins that interact with these channels including recently identified NAADP receptors.
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Affiliation(s)
- Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK.
| | | | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
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2
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Zhang Y, Rabesahala de Meritens C, Beckmann A, Lai FA, Zissimopoulos S. Defective ryanodine receptor N-terminus inter-subunit interaction is a common mechanism in neuromuscular and cardiac disorders. Front Physiol 2022; 13:1032132. [PMID: 36311249 PMCID: PMC9597452 DOI: 10.3389/fphys.2022.1032132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/28/2022] [Indexed: 07/28/2023] Open
Abstract
The ryanodine receptor (RyR) is a homotetrameric channel mediating sarcoplasmic reticulum Ca2+ release required for skeletal and cardiac muscle contraction. Mutations in RyR1 and RyR2 lead to life-threatening malignant hyperthermia episodes and ventricular tachycardia, respectively. In this brief report, we use chemical cross-linking to demonstrate that pathogenic RyR1 R163C and RyR2 R169Q mutations reduce N-terminus domain (NTD) tetramerization. Introduction of positively-charged residues (Q168R, M399R) in the NTD-NTD inter-subunit interface normalizes RyR2-R169Q NTD tetramerization. These results indicate that perturbation of NTD-NTD inter-subunit interactions is an underlying molecular mechanism in both RyR1 and RyR2 pathophysiology. Importantly, our data provide proof of concept that stabilization of this critical RyR1/2 structure-function parameter offers clear therapeutic potential.
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Affiliation(s)
- Yadan Zhang
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | | | - Astrid Beckmann
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - F. Anthony Lai
- College of Medicine and Biomedical Research Centre, Qatar University, Doha, Qatar
| | - Spyros Zissimopoulos
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
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3
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Yin L, Zahradnikova A, Rizzetto R, Boncompagni S, Rabesahala de Meritens C, Zhang Y, Joanne P, Marqués-Sulé E, Aguilar-Sánchez Y, Fernández-Tenorio M, Villejoubert O, Li L, Wang YY, Mateo P, Nicolas V, Gerbaud P, Lai FA, Perrier R, Álvarez JL, Niggli E, Valdivia HH, Valdivia CR, Ramos-Franco J, Zorio E, Zissimopoulos S, Protasi F, Benitah JP, Gómez AM. Impaired Binding to Junctophilin-2 and Nanostructural Alteration in CPVT Mutation. Circ Res 2021; 129:e35-e52. [PMID: 34111951 DOI: 10.1161/circresaha.121.319094] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Liheng Yin
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - Alexandra Zahradnikova
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - Riccardo Rizzetto
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - Simona Boncompagni
- CAST, Department of Neuroscience, Imaging and Clinical Sciences (DNICS), Medicine and Ageing Sciences (DMSI), University Gabriele d'Annunzio, Chieti, Italy (S.B., F.P.)
| | | | - Yadan Zhang
- Swansea University Medical School, Institute of Life Science, Swansea, SA2 8PP, UK (C.R.d.M., Y.Z., S.Z.)
| | - Pierre Joanne
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - Elena Marqués-Sulé
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.).,Physiotherapy, University of Valencia, Valencia, Spain (E.M.-S.)
| | - Yuriana Aguilar-Sánchez
- Physiology and Biophysics, Rush University Medical Center, Chicago, IL, USA (Y.A.-S., J.R.-F.)
| | | | - Olivier Villejoubert
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - Linwei Li
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - Yue Yi Wang
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - Philippe Mateo
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | | | - Pascale Gerbaud
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - F Anthony Lai
- College of Medicine, Biomedical & Pharmaceutical Research Unit, QU Health, & Biomedical Research Centre, Qatar University, Doha, Qatar (F.A.L.)
| | | | - Julio L Álvarez
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.).,Institute of Cardiology, Havana, Cuba (J.L.A.)
| | - Ernst Niggli
- Physiology, University of Bern, Bern, Switzerland (M.F.-T., E.N.)
| | - Héctor H Valdivia
- Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin (H.H.V., C.R.V.)
| | - Carmen R Valdivia
- Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin (H.H.V., C.R.V.)
| | - Josefina Ramos-Franco
- Physiology and Biophysics, Rush University Medical Center, Chicago, IL, USA (Y.A.-S., J.R.-F.)
| | - Esther Zorio
- Cardiology Department and Unidad de Cardiopatías Familiares, Muerte Súbita y Mecanismos de Enfermedad (CaFaMuSMe), Hospital Universitario y Politécnico La Fe and Instituto de Investigación Sanitaria La Fe, Valencia, Spain (E.Z.).,Center for Biomedical Network Research on Cardiovascular diseases (CIBERCV), Madrid, Spain (E.Z.)
| | - Spyros Zissimopoulos
- Swansea University Medical School, Institute of Life Science, Swansea, SA2 8PP, UK (C.R.d.M., Y.Z., S.Z.)
| | - Feliciano Protasi
- CAST, Department of Neuroscience, Imaging and Clinical Sciences (DNICS), Medicine and Ageing Sciences (DMSI), University Gabriele d'Annunzio, Chieti, Italy (S.B., F.P.)
| | - Jean-Pierre Benitah
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
| | - Ana M Gómez
- Signaling and Cardiovascular Pathophysiology - UMR-S 1180, Inserm, Université Paris-Saclay 92296 Châtenay-Malabry, France (L.Y., A.Z., R.R., P.J., E.M.-S., O.V., L.L., Y.Y.W., P.M., P.G., R.P., J.L.A., J.-P.B., A.M.G.)
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4
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Seidel M, de Meritens CR, Johnson L, Parthimos D, Bannister M, Thomas NL, Ozekhome-Mike E, Lai FA, Zissimopoulos S. Identification of an amino-terminus determinant critical for ryanodine receptor/Ca2+ release channel function. Cardiovasc Res 2020; 117:780-791. [PMID: 32077934 PMCID: PMC7898959 DOI: 10.1093/cvr/cvaa043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 12/05/2019] [Accepted: 02/17/2020] [Indexed: 01/12/2023] Open
Abstract
AIMS The cardiac ryanodine receptor (RyR2), which mediates intracellular Ca2+ release to trigger cardiomyocyte contraction, participates in development of acquired and inherited arrhythmogenic cardiac disease. This study was undertaken to characterize the network of inter- and intra-subunit interactions regulating the activity of the RyR2 homotetramer. METHODS AND RESULTS We use mutational investigations combined with biochemical assays to identify the peptide sequence bridging the β8 with β9 strand as the primary determinant mediating RyR2 N-terminus self-association. The negatively charged side chains of two aspartate residues (D179 and D180) within the β8-β9 loop are crucial for the N-terminal inter-subunit interaction. We also show that the RyR2 N-terminus domain interacts with the C-terminal channel pore region in a Ca2+-independent manner. The β8-β9 loop is required for efficient RyR2 subunit oligomerization but it is dispensable for N-terminus interaction with C-terminus. Deletion of the β8-β9 sequence produces unstable tetrameric channels with subdued intracellular Ca2+ mobilization implicating a role for this domain in channel opening. The arrhythmia-linked R176Q mutation within the β8-β9 loop decreases N-terminus tetramerization but does not affect RyR2 subunit tetramerization or the N-terminus interaction with C-terminus. RyR2R176Q is a characteristic hypersensitive channel displaying enhanced intracellular Ca2+ mobilization suggesting an additional role for the β8-β9 domain in channel closing. CONCLUSION These results suggest that efficient N-terminus inter-subunit communication mediated by the β8-β9 loop may constitute a primary regulatory mechanism for both RyR2 channel activation and suppression.
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Affiliation(s)
- Monika Seidel
- Department of Cardiology, School of Medicine, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
| | - Camille Rabesahala de Meritens
- Department of Cardiology, School of Medicine, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
| | - Louisa Johnson
- Department of Cardiology, School of Medicine, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
| | - Dimitris Parthimos
- Department of Cardiology, School of Medicine, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Cancer & Genetics, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | - Mark Bannister
- Department of Cardiology, School of Medicine, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
| | - Nia Lowri Thomas
- Department of Cardiology, School of Medicine, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK
| | - Esizaze Ozekhome-Mike
- Department of Cardiology, School of Medicine, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
| | - Francis Anthony Lai
- College of Medicine, QU Health, and Biomedical Research Centre, Qatar University, Doha, Qatar
| | - Spyros Zissimopoulos
- Department of Cardiology, School of Medicine, Wales Heart Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
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5
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Stanczyk PJ, Seidel M, White J, Viero C, George CH, Zissimopoulos S, Lai FA. Association of cardiac myosin-binding protein-C with the ryanodine receptor channel - putative retrograde regulation? J Cell Sci 2018; 131:jcs.210443. [PMID: 29930088 PMCID: PMC6104826 DOI: 10.1242/jcs.210443] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 05/31/2018] [Indexed: 11/20/2022] Open
Abstract
The cardiac muscle ryanodine receptor-Ca2+ release channel (RyR2) constitutes the sarcoplasmic reticulum (SR) Ca2+ efflux mechanism that initiates myocyte contraction, while cardiac myosin-binding protein-C (cMyBP-C; also known as MYBPC3) mediates regulation of acto-myosin cross-bridge cycling. In this paper, we provide the first evidence for the presence of direct interaction between these two proteins, forming a RyR2-cMyBP-C complex. The C-terminus of cMyBP-C binds with the RyR2 N-terminus in mammalian cells and the interaction is not mediated by a fibronectin-like domain. Notably, we detected complex formation between both recombinant cMyBP-C and RyR2, as well as between the native proteins in cardiac tissue. Cellular Ca2+ dynamics in HEK293 cells is altered upon co-expression of cMyBP-C and RyR2, with lowered frequency of RyR2-mediated spontaneous Ca2+ oscillations, suggesting that cMyBP-C exerts a potential inhibitory effect on RyR2-dependent Ca2+ release. Discovery of a functional RyR2 association with cMyBP-C provides direct evidence for a putative mechanistic link between cytosolic soluble cMyBP-C and SR-mediated Ca2+ release, via RyR2. Importantly, this interaction may have clinical relevance to the observed cMyBP-C and RyR2 dysfunction in cardiac pathologies, such as hypertrophic cardiomyopathy.
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Affiliation(s)
- Paulina J Stanczyk
- Sir Geraint Evans Wales Heart Research Institute, Department of Cardiology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK.,School of Biosciences, Sir Martin Evans Building, College of Biomedical and Life Sciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Monika Seidel
- Sir Geraint Evans Wales Heart Research Institute, Department of Cardiology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK.,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
| | - Judith White
- Sir Geraint Evans Wales Heart Research Institute, Department of Cardiology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK.,School of Biosciences, Sir Martin Evans Building, College of Biomedical and Life Sciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Cedric Viero
- Sir Geraint Evans Wales Heart Research Institute, Department of Cardiology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK.,Institute of Pharmacology and Toxicology, Medical School, Saarland University, Homburg/Saar, Germany
| | - Christopher H George
- Sir Geraint Evans Wales Heart Research Institute, Department of Cardiology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK.,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
| | - Spyros Zissimopoulos
- Sir Geraint Evans Wales Heart Research Institute, Department of Cardiology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK .,Swansea University Medical School, Institute of Life Science, Swansea SA2 8PP, UK
| | - F Anthony Lai
- Sir Geraint Evans Wales Heart Research Institute, Department of Cardiology, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK .,School of Biosciences, Sir Martin Evans Building, College of Biomedical and Life Sciences, Cardiff University, Cardiff CF10 3AX, UK.,College of Medicine, Member of QU Health, Qatar University, P.O. Box 2013, Doha, Qatar
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6
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Stanczyk P, Seidel M, White J, Viero C, George C, Zissimopoulos S, Lai FA. Association of Cardiac Myosin Binding Protein-C with the Ryanodine Receptor-Ca2+ Release Channel: Putative Retrograde Regulation? Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.3359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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7
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Handhle A, Ormonde CE, Thomas NL, Bralesford C, Williams AJ, Lai FA, Zissimopoulos S. Calsequestrin interacts directly with the cardiac ryanodine receptor luminal domain. J Cell Sci 2016; 129:3983-3988. [PMID: 27609834 PMCID: PMC5117208 DOI: 10.1242/jcs.191643] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 09/05/2016] [Indexed: 11/20/2022] Open
Abstract
Cardiac muscle contraction requires sarcoplasmic reticulum (SR) Ca2+ release mediated by the quaternary complex comprising the ryanodine receptor 2 (RyR2), calsequestrin 2 (CSQ2), junctin (encoded by ASPH) and triadin. Here, we demonstrate that a direct interaction exists between RyR2 and CSQ2. Topologically, CSQ2 binding occurs at the first luminal loop of RyR2. Co-expression of RyR2 and CSQ2 in a human cell line devoid of the other quaternary complex proteins results in altered Ca2+-release dynamics compared to cells expressing RyR2 only. These findings provide a new perspective for understanding the SR luminal Ca2+ sensor and its involvement in cardiac physiology and disease.
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Affiliation(s)
- Ahmed Handhle
- Sir Geraint Evans Wales Heart Research Institute, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK.,Medical Biochemistry Department, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Chloe E Ormonde
- Sir Geraint Evans Wales Heart Research Institute, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | - N Lowri Thomas
- Sir Geraint Evans Wales Heart Research Institute, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | - Catherine Bralesford
- Sir Geraint Evans Wales Heart Research Institute, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | - Alan J Williams
- Sir Geraint Evans Wales Heart Research Institute, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | - F Anthony Lai
- Sir Geraint Evans Wales Heart Research Institute, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | - Spyros Zissimopoulos
- Sir Geraint Evans Wales Heart Research Institute, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
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8
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Stanczyk PJ, Lai FA, Zissimopoulos S. Genetic and Biochemical Approaches for In Vivo and In Vitro Assessment of Protein Oligomerization: The Ryanodine Receptor Case Study. J Vis Exp 2016. [PMID: 27500320 PMCID: PMC5065051 DOI: 10.3791/54271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Oligomerization is often a structural requirement for proteins to accomplish their specific cellular function. For instance, tetramerization of the ryanodine receptor (RyR) is necessary for the formation of a functional Ca2+ release channel pore. Here, we describe detailed protocols for the assessment of protein self-association, including yeast two-hybrid (Y2H), co-immunoprecipitation (co-IP) and chemical cross-linking assays. In the Y2H system, protein self-interaction is detected by β-galactosidase assay in yeast co-expressing GAL4 bait and target fusions of the test protein. Protein self-interaction is further assessed by co-IP using HA- and cMyc-tagged fusions of the test protein co-expressed in mammalian HEK293 cells. The precise stoichiometry of the protein homo-oligomer is examined by cross-linking and SDS-PAGE analysis following expression in HEK293 cells. Using these different but complementary techniques, we have consistently observed the self-association of the RyR N-terminal domain and demonstrated its intrinsic ability to form tetramers. These methods can be applied to protein-protein interaction and homo-oligomerization studies of other mammalian integral membrane proteins.
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9
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Domingo D, Neco P, Fernández-Pons E, Zissimopoulos S, Molina P, Olagüe J, Suárez-Mier MP, Lai FA, Gómez AM, Zorio E. Rasgos no ventriculares, clínicos y funcionales de la mutación RyR2R420Q causante de taquicardia ventricular polimórfica catecolaminérgica. Rev Esp Cardiol 2015. [DOI: 10.1016/j.recesp.2014.04.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Domingo D, Neco P, Fernández-Pons E, Zissimopoulos S, Molina P, Olagüe J, Suárez-Mier MP, Lai FA, Gómez AM, Zorio E. Non-ventricular, Clinical, and Functional Features of the RyR2(R420Q) Mutation Causing Catecholaminergic Polymorphic Ventricular Tachycardia. ACTA ACUST UNITED AC 2014; 68:398-407. [PMID: 25440180 DOI: 10.1016/j.rec.2014.04.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 04/28/2014] [Indexed: 11/18/2022]
Abstract
INTRODUCTION AND OBJECTIVES Catecholaminergic polymorphic ventricular tachycardia is a malignant disease, due to mutations in proteins controlling Ca(2+) homeostasis. While the phenotype is characterized by polymorphic ventricular arrhythmias under stress, supraventricular arrhythmias may occur and are not fully characterized. METHODS Twenty-five relatives from a Spanish family with several sudden deaths were evaluated with electrocardiogram, exercise testing, and optional epinephrine challenge. Selective RyR2 sequencing in an affected individual and cascade screening in the rest of the family was offered. The RyR2(R420Q) mutation was generated in HEK-293 cells using site-directed mutagenesis to conduct in vitro functional studies. RESULTS The exercise testing unmasked catecholaminergic polymorphic ventricular tachycardia in 8 relatives (sensitivity = 89%; positive predictive value = 100%; negative predictive value = 93%), all of them carrying the heterozygous RyR2(R420Q) mutation, which was also present in the proband and a young girl without exercise testing, a 91% penetrance at the end of the follow-up. Remarkably, sinus bradycardia, atrial and junctional arrhythmias, and/or giant post-effort U-waves were identified in patients. Upon permeabilization and in intact cells, the RyR2(R420Q) expressing cells showed a smaller peak of Ca(2+) release than RyR2 wild-type cells. However, at physiologic intracellular Ca(2+) concentration, equivalent to the diastolic cytosolic concentration, the RyR2(R420Q) released more Ca(2+) and oscillated faster than RyR2 wild-type cells. CONCLUSIONS The missense RyR2(R420Q) mutation was identified in the N-terminus of the RyR2 gene in this highly symptomatic family. Remarkably, this mutation is associated with sinus bradycardia, atrial and junctional arrhythmias, and giant U-waves. Collectively, functional heterologous expression studies suggest that the RyR2(R420Q) behaves as an aberrant channel, as a loss- or gain-of-function mutation depending on cytosolic intracellular Ca(2+) concentration.
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Affiliation(s)
- Diana Domingo
- Servicio de Cardiología, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Patricia Neco
- Inserm, U769, Université de Paris Sud, IFR141, LabEx Lermit, Châtenay-Malabry, France
| | - Elena Fernández-Pons
- Grupo de Investigación acreditado de Hemostasia, Trombosis, Arteriosclerosis y Biología Vascular, Instituto de Investigación Sanitaria La Fe, Valencia, Spain
| | - Spyros Zissimopoulos
- Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff, United Kingdom
| | - Pilar Molina
- Servicio de Histopatología, Instituto de Medicina Legal, Valencia, Spain
| | - José Olagüe
- Servicio de Cardiología, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - M Paz Suárez-Mier
- Servicio de Histopatología, Instituto Nacional de Toxicología y Ciencias Forenses, Madrid, Spain
| | - F Anthony Lai
- Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff, United Kingdom
| | - Ana M Gómez
- Inserm, U769, Université de Paris Sud, IFR141, LabEx Lermit, Châtenay-Malabry, France
| | - Esther Zorio
- Servicio de Cardiología, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
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11
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Seidel M, Thomas NL, Williams AJ, Lai FA, Zissimopoulos S. Dantrolene rescues aberrant N-terminus intersubunit interactions in mutant pro-arrhythmic cardiac ryanodine receptors. Cardiovasc Res 2014; 105:118-28. [PMID: 25411383 DOI: 10.1093/cvr/cvu240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS The ryanodine receptor (RyR2) is an intracellular Ca(2+) release channel essential for cardiac excitation-contraction coupling. Abnormal RyR2 channel function results in the generation of arrhythmias and sudden cardiac death. The present study was undertaken to investigate the mechanistic basis of RyR2 dysfunction in inherited arrhythmogenic cardiac disease. METHODS AND RESULTS We present several lines of complementary evidence, indicating that the arrhythmia-associated L433P mutation disrupts RyR2 N-terminus self-association. A combination of yeast two-hybrid, co-immunoprecipitation, and chemical cross-linking assays collectively demonstrate that a RyR2 N-terminal fragment carrying the L433P mutation displays substantially reduced self-interaction compared with wild type. Moreover, sucrose density gradient centrifugation reveals that the L433P mutation impairs tetramerization of the full-length channel. [(3)H]Ryanodine-binding assays demonstrate that disrupted N-terminal intersubunit interactions within RyR2(L433P) confer an altered sensitivity to Ca(2+) activation. Calcium imaging of RyR2(L433P)-expressing cells reveals substantially prolonged Ca(2+) transients and reduced Ca(2+) store content indicating defective channel closure. Importantly, dantrolene treatment reverses the L433P mutation-induced impairment and restores channel function. CONCLUSION The N-terminus domain constitutes an important structural determinant for the functional oligomerization of RyR2. Our findings are consistent with defective N-terminus self-association as a molecular mechanism underlying RyR2 channel deregulation in inherited arrhythmogenic cardiac disease. Significantly, the therapeutic action of dantrolene may occur via the restoration of normal RyR2 N-terminal intersubunit interactions.
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Affiliation(s)
- Monika Seidel
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - N Lowri Thomas
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - Alan J Williams
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - F Anthony Lai
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - Spyros Zissimopoulos
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
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12
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Ljubojevic S, Radulovic S, Leitinger G, Sedej S, Sacherer M, Holzer M, Winkler C, Pritz E, Mittler T, Schmidt A, Sereinigg M, Wakula P, Zissimopoulos S, Bisping E, Post H, Marsche G, Bossuyt J, Bers DM, Kockskämper J, Pieske B. Early remodeling of perinuclear Ca2+ stores and nucleoplasmic Ca2+ signaling during the development of hypertrophy and heart failure. Circulation 2014; 130:244-55. [PMID: 24928680 PMCID: PMC4101040 DOI: 10.1161/circulationaha.114.008927] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND A hallmark of heart failure is impaired cytoplasmic Ca(2+) handling of cardiomyocytes. It remains unknown whether specific alterations in nuclear Ca(2+) handling via altered excitation-transcription coupling contribute to the development and progression of heart failure. METHODS AND RESULTS Using tissue and isolated cardiomyocytes from nonfailing and failing human hearts, as well as mouse and rabbit models of hypertrophy and heart failure, we provide compelling evidence for structural and functional changes of the nuclear envelope and nuclear Ca(2+) handling in cardiomyocytes as remodeling progresses. Increased nuclear size and less frequent intrusions of the nuclear envelope into the nuclear lumen indicated altered nuclear structure that could have functional consequences. In the (peri)nuclear compartment, there was also reduced expression of Ca(2+) pumps and ryanodine receptors, increased expression of inositol-1,4,5-trisphosphate receptors, and differential orientation among these Ca(2+) transporters. These changes were associated with altered nucleoplasmic Ca(2+) handling in cardiomyocytes from hypertrophied and failing hearts, reflected as increased diastolic Ca(2+) levels with diminished and prolonged nuclear Ca(2+) transients and slowed intranuclear Ca(2+) diffusion. Altered nucleoplasmic Ca(2+) levels were translated to higher activation of nuclear Ca(2+)/calmodulin-dependent protein kinase II and nuclear export of histone deacetylases. Importantly, the nuclear Ca(2+) alterations occurred early during hypertrophy and preceded the cytoplasmic Ca(2+) changes that are typical of heart failure. CONCLUSIONS During cardiac remodeling, early changes of cardiomyocyte nuclei cause altered nuclear Ca(2+) signaling implicated in hypertrophic gene program activation. Normalization of nuclear Ca(2+) regulation may therefore be a novel therapeutic approach to prevent adverse cardiac remodeling.
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Affiliation(s)
- Senka Ljubojevic
- Department of Cardiology, Medical University of Graz, Graz,
Austria
- Ludwig Boltzmann Institute for Translational Heart Failure
Research, Graz, Austria
- Department of Pharmacology, University of California,
Davis, CA
| | | | - Gerd Leitinger
- Institute of Cell Biology, Histology and Embryology,
Medical University of Graz, Graz, Austria
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz,
Austria
- Ludwig Boltzmann Institute for Translational Heart Failure
Research, Graz, Austria
| | - Michael Sacherer
- Department of Cardiology, Medical University of Graz, Graz,
Austria
| | - Michael Holzer
- Institute of Experimental and Clinical Pharmacology,
Medical University of Graz, Graz, Austria
| | - Claudia Winkler
- Department of Cardiology, Medical University of Graz, Graz,
Austria
| | - Elisabeth Pritz
- Institute of Cell Biology, Histology and Embryology,
Medical University of Graz, Graz, Austria
| | - Tobias Mittler
- Department of Cardiology, Medical University of Graz, Graz,
Austria
| | - Albrecht Schmidt
- Department of Cardiology, Medical University of Graz, Graz,
Austria
| | - Michael Sereinigg
- Division of Transplantation Surgery, Medical University of
Graz, Graz, Austria
| | - Paulina Wakula
- Department of Cardiology, Medical University of Graz, Graz,
Austria
- Ludwig Boltzmann Institute for Translational Heart Failure
Research, Graz, Austria
| | - Spyros Zissimopoulos
- Wales Heart Research Institute, Cardiff University School
of Medicine, Cardiff, United Kindgom
| | - Egbert Bisping
- Department of Cardiology, Medical University of Graz, Graz,
Austria
- Ludwig Boltzmann Institute for Translational Heart Failure
Research, Graz, Austria
| | - Heiner Post
- Department of Cardiology, Medical University of Graz, Graz,
Austria
| | - Gunther Marsche
- Institute of Experimental and Clinical Pharmacology,
Medical University of Graz, Graz, Austria
| | - Julie Bossuyt
- Department of Pharmacology, University of California,
Davis, CA
| | - Donald M. Bers
- Department of Pharmacology, University of California,
Davis, CA
| | - Jens Kockskämper
- Institute of Pharmacology and Clinical Pharmacy,
Philipps-University of Marburg, Marburg, Germany
| | - Burkert Pieske
- Department of Cardiology, Medical University of Graz, Graz,
Austria
- Ludwig Boltzmann Institute for Translational Heart Failure
Research, Graz, Austria
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13
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Viero C, Euden J, Mason SA, Seidel MK, Thomas NL, Zissimopoulos S, Williams AJ. P373Two key regions of the human cardiac ryanodine receptor calcium release channel modulate its gating properties in a dual manner. Cardiovasc Res 2014. [DOI: 10.1093/cvr/cvu091.56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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14
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Seidel M, Stanczyk PJ, Lai FA, Zissimopoulos S. Mapping the Interacting Sites Mediating Tetramerisation of Ryanodine Receptor Amino-Terminus. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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15
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Lam AK, Galione A, Lai FA, Zissimopoulos S. Hax-1 identified as a two-pore channel (TPC)-binding protein. FEBS Lett 2013; 587:3782-6. [DOI: 10.1016/j.febslet.2013.10.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/18/2013] [Accepted: 10/21/2013] [Indexed: 10/26/2022]
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16
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Zissimopoulos S, Viero C, Seidel M, Cumbes B, White J, Cheung I, Stewart R, Jeyakumar LH, Fleischer S, Mukherjee S, Thomas NL, Williams AJ, Lai FA. N-terminus oligomerization regulates the function of cardiac ryanodine receptors. J Cell Sci 2013; 126:5042-51. [PMID: 23943880 DOI: 10.1242/jcs.133538] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ryanodine receptor (RyR) is an ion channel composed of four identical subunits mediating calcium efflux from the endo/sarcoplasmic reticulum of excitable and non-excitable cells. We present several lines of evidence indicating that the RyR2 N-terminus is capable of self-association. A combination of yeast two-hybrid screens, co-immunoprecipitation analysis, chemical crosslinking and gel filtration assays collectively demonstrate that a RyR2 N-terminal fragment possesses the intrinsic ability to oligomerize, enabling apparent tetramer formation. Interestingly, N-terminus tetramerization mediated by endogenous disulfide bond formation occurs in native RyR2, but notably not in RyR1. Disruption of N-terminal inter-subunit interactions within RyR2 results in dysregulation of channel activation at diastolic Ca(2+) concentrations from ryanodine binding and single channel measurements. Our findings suggest that the N-terminus interactions mediating tetramer assembly are involved in RyR channel closure, identifying a crucial role for this structural association in the dynamic regulation of intracellular Ca(2+) release.
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Affiliation(s)
- Spyros Zissimopoulos
- Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
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17
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Seidel MK, Lai FA, Zissimopoulos S. The L433P Arrhythmia-Linked Mutation Disrupts Amino-Terminus Oligomerisation of the Human Cardiac Ryanodine Receptor. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.2455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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18
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Zissimopoulos S, Marsh J, Lai FA. Oligomerisation of the Inositol Trisphosphate Receptor Amino-Terminus. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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19
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Zissimopoulos S, Seifan S, Maxwell C, Williams AJ, Lai FA. Disparities in the association of the ryanodine receptor and the FK506-binding proteins in mammalian heart. J Cell Sci 2012; 125:1759-69. [PMID: 22328519 DOI: 10.1242/jcs.098012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The FK506-binding proteins (FKBP12 and FKBP12.6; also known as FKBP1A and FKBP1B, respectively) are accessory subunits of the ryanodine receptor (RyR) Ca(2+) release channel. Aberrant RyR2-FKBP12.6 interactions have been proposed to be the underlying cause of channel dysfunction in acquired and inherited cardiac disease. However, the stoichiometry of the RyR2 association with FKBP12 or FKBP12.6 in mammalian heart is currently unknown. Here, we describe detailed quantitative analysis of cardiac stoichiometry between RyR2 and FKBP12 or FKBP12.6 using immunoblotting and [(3)H]ryanodine-binding assays, revealing striking disparities between four mammalian species. In mouse and pig heart, RyR2 is found complexed with both FKBP12 and FKBP12.6, although the former is the most abundant isoform. In rat heart, RyR2 is predominantly associated with FKBP12.6, whereas in rabbit it is associated with FKBP12 only. Co-immunoprecipitation experiments demonstrate RyR2-specific interaction with both FKBP isoforms in native cardiac tissue. Assuming four FKBP-binding sites per RyR2 tetramer, only a small proportion of available sites are occupied by endogenous FKBP12.6. FKBP interactions with RyR2 are very strong and resistant to drug (FK506, rapamycin and cyclic ADPribose) and redox (H(2)O(2) and diamide) treatment. By contrast, the RyR1-FKBP12 association in skeletal muscle is readily disrupted under oxidative conditions. This is the first study to directly assess association of endogenous FKBP12 and FKBP12.6 with RyR2 in native cardiac tissue. Our results challenge the widespread perception that RyR2 associates exclusively with FKBP12.6 to near saturation, with important implications for the role of the FK506-binding proteins in RyR2 pathophysiology and cardiac disease.
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Affiliation(s)
- Spyros Zissimopoulos
- Wales Heart Research Institute, Department of Cardiology, Cardiff University School of Medicine, Cardiff, UK.
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20
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Seidel MK, Lai F, Zissimopoulos S. Oligomerisation of the Human Cardiac Ryanodine Receptor Amino-Terminus. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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21
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Zahradnikova, A, Neco P, Morel E, Dominguez Rodriguez A, Zissimopoulos S, Lai FA, Benitah JP, Zorio E, Maria Gomez A. In Vitro Characterization of a Novel N-Terminal CPVT RyR Mutation. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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22
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Gómez AM, Rueda A, Sainte-Marie Y, Pereira L, Zissimopoulos S, Zhu X, Schaub R, Perrier E, Perrier R, Latouche C, Richard S, Picot MC, Jaisser F, Lai FA, Valdivia HH, Benitah JP. Mineralocorticoid modulation of cardiac ryanodine receptor activity is associated with downregulation of FK506-binding proteins. Circulation 2009; 119:2179-87. [PMID: 19364981 DOI: 10.1161/circulationaha.108.805804] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND The mineralocorticoid pathway is involved in cardiac arrhythmias associated with heart failure through mechanisms that are incompletely understood. Defective regulation of the cardiac ryanodine receptor (RyR) is an important cause of the initiation of arrhythmias. Here, we examined whether the aldosterone pathway might modulate RyR function. METHODS AND RESULTS Using the whole-cell patch clamp method, we observed an increase in the occurrence of delayed afterdepolarizations during action potential recordings in isolated adult rat ventricular myocytes exposed for 48 hours to aldosterone 100 nmol/L, in freshly isolated myocytes from transgenic mice with human mineralocorticoid receptor expression in the heart, and in wild-type littermates treated with aldosterone. Sarcoplasmic reticulum Ca(2+) load and RyR expression were not altered; however, RyR activity, visualized in situ by confocal microscopy, was increased in all cells, as evidenced by an increased occurrence and redistribution to long-lasting and broader populations of spontaneous Ca(2+) sparks. These changes were associated with downregulation of FK506-binding proteins (FKBP12 and 12.6), regulatory proteins of the RyR macromolecular complex. CONCLUSIONS We suggest that in addition to modulation of Ca(2+) influx, overstimulation of the cardiac mineralocorticoid pathway in the heart might be a major upstream factor for aberrant Ca(2+) release during diastole, which contributes to cardiac arrhythmia in heart failure.
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23
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Abstract
The RyR (ryanodine receptor)/calcium release channel contains a number of highly reactive thiol groups that endow it with redox sensitivity. In general, oxidizing conditions favour channel opening, while reducing conditions have the opposite effect. Thiol modification affects the channel sensitivity to its principal effectors, Ca2+, Mg2+ and ATP, and alters RyR protein interactions. Here, we give a brief account of the major findings and prevailing views in the field.
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Affiliation(s)
- S Zissimopoulos
- Wales Heart Research Institute, Department of Cardiology, Cardiff University School of Medicine, Cardiff CF14 4XN, UK.
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24
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Abstract
The ryanodine receptor (RyR) is a widely expressed intracellular calcium (Ca(2+))-release channel regulating processes such as muscle contraction and neurotransmission. Snapin, a ubiquitously expressed SNARE-associated protein, has been implicated in neurotransmission. Here, we report the identification of snapin as a novel RyR2-interacting protein. Snapin binds to a 170-residue predicted ryanodine receptor cytosolic loop (RyR2 residues 4596-4765), containing a hydrophobic segment required for snapin interaction. Ryanodine receptor binding of snapin is not isoform specific and is conserved in homologous RyR1 and RyR3 fragments. Consistent with peptide fragment studies, snapin interacts with the native ryanodine receptor from skeletal muscle, heart and brain. The snapin-RyR1 association appears to sensitise the channel to Ca(2+) activation in [(3)H]ryanodine-binding studies. Deletion analysis indicates that the ryanodine receptor interacts with the snapin C-terminus, the same region as the SNAP25-binding site. Competition experiments with native ryanodine receptor and SNAP25 suggest that these two proteins share an overlapping binding site on snapin. Thus, regulation of the association between ryanodine receptor and snapin might constitute part of the elusive molecular mechanism by which ryanodine-sensitive Ca(2+) stores modulate neurosecretion.
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Affiliation(s)
- Spyros Zissimopoulos
- Wales Heart Research Institute, Department of Cardiology, Cardiff University School of Medicine, Heath Park, UK.
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25
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Abstract
The ryanodine receptor (RyR) calcium release channel functions as a redox sensor that is sensitive to channel modulators. The FK506-binding protein (FKBP) is an important regulator of channel activity, and disruption of the RyR2-FKBP12.6 association has been implicated in cardiac disease. In the present study, we investigated whether the RyR-FKBP association is redox-regulated. Using co-immunoprecipitation assays of solubilized native RyR2 from cardiac muscle sarcoplasmic reticulum (SR) with recombinant [(35)S]FKBP12.6, we found that the sulfydryl-oxidizing agents, H(2)O(2) and diamide, result in diminished RyR2-FKBP12.6 binding. Co-sedimentation experiments of cardiac SR vesicles with [(35)S]FKBP12.6 also demonstrated that oxidizing reagents decreased FKBP binding. Matching results were obtained with skeletal muscle SR. Notably, H(2)O(2) and diamide differentially affected the RyR2-FKBP12.6 interaction, decreasing binding to approximately 75 and approximately 50% of control, respectively. In addition, the effect of H(2)O(2) was negligible when the channel was in its closed state or when applied after FKBP binding had occurred, whereas diamide was always effective. A cysteine-null mutant FKBP12.6 retained redox-sensitive interaction with RyR2, suggesting that the effect of the redox reagents is exclusively via sites on the ryanodine receptor. K201 (or JTV519), a drug that has been proposed to prevent FKBP12.6 dissociation from the RyR2 channel complex, did not restore normal FKBP binding under oxidizing conditions. Our results indicate that the redox state of the RyR is intimately connected with FKBP binding affinity.
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Affiliation(s)
- Spyros Zissimopoulos
- Wales Heart Research Institute, Department of Cardiology, Cardiff University School of Medicine, Cardiff CF14 4XN, United Kingdom.
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26
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De Crescenzo V, Fogarty KE, ZhuGe R, Tuft RA, Lifshitz LM, Carmichael J, Bellvé KD, Baker SP, Zissimopoulos S, Lai FA, Lemos JR, Walsh JV. Dihydropyridine receptors and type 1 ryanodine receptors constitute the molecular machinery for voltage-induced Ca2+ release in nerve terminals. J Neurosci 2006; 26:7565-74. [PMID: 16855084 PMCID: PMC6674279 DOI: 10.1523/jneurosci.1512-06.2006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ca2+ stores were studied in a preparation of freshly dissociated terminals from hypothalamic magnocellular neurons. Depolarization from a holding level of -80 mV in the absence of extracellular Ca2+ elicited Ca2+ release from intraterminal stores, a ryanodine-sensitive process designated as voltage-induced Ca2+ release (VICaR). The release took one of two forms: an increase in the frequency but not the quantal size of Ca2+ syntillas, which are brief, focal Ca2+ transients, or an increase in global [Ca2+]. The present study provides evidence that the sensors of membrane potential for VICaR are dihydropyridine receptors (DHPRs). First, over the range of -80 to -60 mV, in which there was no detectable voltage-gated inward Ca2+ current, syntilla frequency was increased e-fold per 8.4 mV of depolarization, a value consistent with the voltage sensitivity of DHPR-mediated VICaR in skeletal muscle. Second, VICaR was blocked by the dihydropyridine antagonist nifedipine, which immobilizes the gating charge of DHPRs but not by Cd2+ or FPL 64176 (methyl 2,5 dimethyl-4[2-(phenylmethyl)benzoyl]-1H-pyrrole-3-carboxylate), a non-dihydropyridine agonist specific for L-type Ca2+ channels, having no effect on gating charge movement. At 0 mV, the IC50 for nifedipine blockade of VICaR in the form of syntillas was 214 nM in the absence of extracellular Ca2+. Third, type 1 ryanodine receptors, the type to which DHPRs are coupled in skeletal muscle, were detected immunohistochemically at the plasma membrane of the terminals. VICaR may constitute a new link between neuronal activity, as signaled by depolarization, and a rise in intraterminal Ca2+.
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27
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Liu N, Colombi B, Memmi M, Zissimopoulos S, Rizzi N, Negri S, Imbriani M, Napolitano C, Lai FA, Priori SG. Arrhythmogenesis in catecholaminergic polymorphic ventricular tachycardia: insights from a RyR2 R4496C knock-in mouse model. Circ Res 2006; 99:292-8. [PMID: 16825580 DOI: 10.1161/01.res.0000235869.50747.e1] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited disease characterized by life threatening arrhythmias and mutations in the gene encoding the ryanodine receptor (RyR2). Disagreement exists on whether (1) RyR2 mutations induce abnormal calcium transients in the absence of adrenergic stimulation; (2) decreased affinity of mutant RyR2 for FKBP12.6 causes CPVT; (3) K201 prevent arrhythmias by normalizing the FKBP12.6-RyR2 binding. We studied ventricular myocytes isolated from wild-type (WT) and knock-in mice harboring the R4496C mutation (RyR2(R4496C+/-)). Pacing protocols did not elicit delayed afterdepolarizations (DADs) (n=20) in WT but induced DADs in 21 of 33 (63%) RyR2(R4496C+/-) myocytes (P=0.001). Superfusion with isoproterenol (30 nmol/L) induced small DADs (45%) and no triggered activity in WT myocytes, whereas it elicited DADs in 87% and triggered activity in 60% of RyR2(R4496C+/-) myocytes (P=0.001). DADs and triggered activity were abolished by ryanodine (10 micromol/L) but not by K201 (1 micromol/L or 10 micromol/L). In vivo administration of K201 failed to prevent induction of polymorphic ventricular tachycardia (VT) in RyR2(R4496C+/-) mice. Measurement of the FKBP12.6/RyR2 ratio in the heavy sarcoplasmic reticulum membrane showed normal RyR2-FKBP12.6 interaction both in WT and RyR2(R4496C+/-) either before and after treatment with caffeine and epinephrine. We suggest that (1) triggered activity is the likely arrhythmogenic mechanism of CPVT; (2) K201 fails to prevent DADs in RyR2(R4496C+/-) myocytes and ventricular arrhythmias in RyR2(R4496C+/-) mice; and (3) RyR2-FKBP12.6 interaction in RyR2(R4496C+/-) is identical to that of WT both before and after epinephrine and caffeine, thus suggesting that it is unlikely that the R4496C mutation interferes with the RyR2/FKBP12.6 complex.
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Affiliation(s)
- Nian Liu
- Molecular Cardiology, IRCCS Fondazione Salvatore Maugeri, Pavia, Italy
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28
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Abstract
The immunophilin, FK506-binding protein (FKBP12), is an essential component of the ryanodine receptor channel complex of skeletal muscle (RyR1) and modulates intracellular calcium signaling from the endoplasmic reticulum. The cardiac muscle RyR isoform (RyR2) specifically associates with a distinct FKBP isoform, FKBP12.6. Previous studies have led to the proposal that the central domain of RyR1 exclusively mediates the interaction with FKBP12. To characterize the topography of the FKBP12.6 binding site on the human cardiac RyR2, we have applied complementary protein-protein interaction methods using both in vivoyeast two-hybrid analysis and in vitroimmunoprecipitation experiments. Our results indicate an absence of interaction of FKBP12/12.6 with fragments containing the central domain of either RyR1, RyR2, or RyR3. Furthermore, no interaction was detected between FKBP12.6 with a series of overlapping fragments encompassing the entire RyR2, either individually or in multiple combination. We also found that a distinct, alternatively spliced variant of FKBP12.6 was unable to interact with RyR. In contrast, we successfully demonstrated a robust association between the cytoplasmic domain of transforming growth factor-beta receptor type I and both FKBP12 and FKBP12.6 in parallel positive control experiments, as well as between native RyR2 and FKBP12.6. These results suggest that the specific interaction of FKBP12.6 with RyR2, and generally of FKBPs with any RyR isoform, is not readily reconstituted by peptide fragments corresponding to central RyR domains. Further structural analysis will be necessary to unravel this intricate signaling system and the current model of FKBP12-RyR interaction via a single, central RyR epitope may therefore require revision.
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Affiliation(s)
- Spyros Zissimopoulos
- Wales Heart Research Institute, Department of Cardiology, Wales College of Medicine, Cardiff University, UK.
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29
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Abstract
The ryanodine receptor-calcium release channel complex (RyR) plays a pivotal role in excitation-contraction coupling in skeletal and cardiac muscle. RyR channel activity is modulated by interaction with FK506-binding protein (FKBP), and disruption of the RyR-FKBP association has been implicated in cardiomyopathy, cardiac hypertrophy, and heart failure. Evidence for an interaction between RyR and FKBP is well documented, both in skeletal muscle (RyR1-FKBP12) and in cardiac muscle (RyR2-FKBP12.6), however definition of the FKBP-binding site remains elusive. Early reports proposed interaction of a short RyR central domain with FKBP12/12.6, however this site has been questioned, and recently an alternative FKBP12.6 interaction site has been identified within the N-terminal half of RyR2. In this study, we report evidence for the human RyR2 C-terminal domain as a novel FKBP12.6-binding site. Using competition binding assays, we find that short C-terminal RyR2 fragments can displace bound FKBP12.6 from the native RyR2, although they are unable to exclusively support interaction with FKBP12.6. However, expression of a large RyR2 C-terminal construct in mammalian cells encompassing the pore-forming transmembrane domains exhibits rapamycin-sensitive binding specifically to FKBP12.6 but not to FKBP12. We also obtained some evidence for involvement of the RyR2 N-terminal, but not the central domain, in FKBP12.6 interaction. Our studies suggest that a novel interaction site for FKBP12.6 may be present at the RyR2 C terminus, proximal to the channel pore, a sterically appropriate location that would enable this protein to play a central role in the modulation of this critical ion channel.
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Affiliation(s)
- Spyros Zissimopoulos
- Wales Heart Research Institute, Department of Cardiology, University of Wales College of Medicine, Cardiff CF14 4XN, UK
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30
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Abstract
Specific interactions between adjacent ryanodine receptor (RyR) molecules to form ordered two-dimensional arrays in the membrane have been demonstrated using electron microscopy both in situ, in tissues and cells, and in vitro, with the purified protein. RyR interoligomeric association has also been inferred from observations of simultaneous channel gating during multi-RyR channel recordings in lipid bilayers. In this study, we report experiments designed to identify the region(s) of the RyR molecule, participating in this reciprocal interaction. Using epitope-specific antibodies, we identified a RyR tryptic fragment that specifically bound the intact immobilized RyR. Three overlapping RyR fragments encompassing this epitope, expressed using an in vitro mammalian expression system, were immunoprecipitated by RyR. To refine the binding regions, smaller RyR fragments were expressed as glutathione S-transferase (GST) fusion proteins, and their binding to RyR was monitored using a "sandwich" enzyme-linked immunosorbent assay. Three GST-RyR fusion proteins demonstrated specific binding, dependent upon ionic strength. Binding was greatest at 50-150 mm NaCl for two GST-RyR constructs, and a third GST-RyR construct demonstrated maximum binding between 150 and 450 mm NaCl. The binding at high NaCl concentration suggested involvement of a hydrophobic interaction. In silico analysis of secondary structure showed evidence of coil regions in two of these RyR fragment sequences, which might explain these data. In GST pull-down assays, these same three fragments captured RyR2, and two of them retained RyR1. These results identify a region at the center of the linear RyR (residues 2540-3207 of human RyR2) which is able to bind to the RyR oligomer. This region may constitute a specific subdomain participating in RyR-RyR interaction.
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Affiliation(s)
- Lynda M Blayney
- Wales Heart Research Institute, Department of Cardiology, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, Wales, United Kingdom.
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31
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Stewart R, Zissimopoulos S, Lai FA. Oligomerization of the cardiac ryanodine receptor C-terminal tail. Biochem J 2003; 376:795-9. [PMID: 12959641 PMCID: PMC1223808 DOI: 10.1042/bj20030597] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2003] [Revised: 08/22/2003] [Accepted: 09/08/2003] [Indexed: 11/17/2022]
Abstract
The C-terminal 100 amino acids of the RyR (ryanodine receptor), referred to as the C-terminal tail, is a highly conserved sequence that is present in all known RyR isoforms and which has been implicated in channel function. Deleting the final 15 amino acids from the full-length skeletal muscle RyR resulted in an inactive channel, attributed to impaired assembly of a tetrameric RyR complex [Gao, Tripathy, Lu and Meissner (1997) FEBS Lett. 412, 223-226]. To account for these observations, the C-terminal tail itself may be an important molecular determinant of oligomerization. Alternatively, the large N-terminal cytoplasmic domain may fold back upon itself to interact with the C-terminal tail to provide a correctly folded tetrameric structure. We explored these possibilities for RyR2 (cardiac RyR) using the yeast two-hybrid interaction assay and in vitro translation followed by immunoprecipitation and chemical cross-linking. The data indicate that the C-terminal tail of RyR2 is capable of self-tetramerization. Moreover, a truncated C-terminal tail, lacking the final 15 amino acids, failed to self-associate. These observations suggest that the intrinsic ability of the RyR C-terminal tail to self-tetramerize may be vitally important for the oligomeric assembly of the native RyR channel.
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Affiliation(s)
- Richard Stewart
- Wales Heart Research Institute, Department of Cardiology, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK
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