Submitted on December 20, 2005
Revised on March 14, 2006
Accepted on March 24, 2006
From the Department of Physiology and Cell Biology (D.T., S.V.-K., Z.K., I.G., R.T., S.V., S.G.), Heart and Lung Research Institute, Ohio State University, Columbus; Dipartimento di Scienze Biomediche Sperimentali dell’Università di Padova (A.N., G.V., P.V.), Istituto Interuniversitario di Miologia, Padova, Italy; Department of Molecular Cardiology (M.S., C.N., S.G.P.), Fondazione Salvatore Maugeri, IRCCS, Pavia, Italy; University Hospital Leiden (N.A.B), The Netherlands; Department of Cell Biology and Biochemistry (S.C.W.), Texas Tech University Health Science Center, Lubbock; and Southwest Cancer Center at University Medical Center (S.C.W.), Lubbock, Texas.
* To whom correspondence should be addressed. E-mail: Sandor.Gyorke{at}osumc.edu.
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a familial arrhythmogenic disorder associated with mutations in the cardiac ryanodine receptor (RyR2) and cardiac calsequestrin (CASQ2) genes. Previous in vitro studies suggested that RyR2 and CASQ2 interact as parts of a multimolecular Ca-signaling complex; however, direct evidence for such interactions and their potential significance to myocardial function remain to be determined. We identified a novel CASQ2 mutation in a young female with a structurally normal heart and unexplained syncopal episodes. This mutation results in the nonconservative substitution of glutamine for arginine at amino acid 33 of CASQ2 (R33Q). Adenoviral-mediated expression of CASQ2R33Q in adult rat myocytes led to an increase in excitation-contraction coupling gain and to more frequent occurrences of spontaneous propagating (Ca waves) and local Ca signals (sparks) with respect to control cells expressing wild-type CASQ2 (CASQ2WT). As revealed by a Ca indicator trapped inside the sarcoplasmic reticulum (SR) of permeabilized myocytes, the Ca waves occurred at a reduced intra-SR [Ca] accounting for the increased frequency of Ca waves in CASQ2R33Q-expressing myocytes. Recombinant CASQ2WT and CASQ2R33Q exhibited similar Ca-binding capacities in vitro; however, the mutant protein lacked the ability of its WT counterpart to inhibit RyR2 activity at low luminal [Ca] in planar lipid bilayers. We conclude that the R33Q mutation disrupts interactions of CASQ2 with the RyR2 channel complex and impairs regulation of RyR2 by luminal Ca. These results show that intracellular Ca cycling in normal heart relies on an intricate interplay of CASQ2 with the proteins of the RyR2 channel complex and that disruption of these interactions can lead to cardiac arrhythmia.
This article has been cited by other articles:
![]() |
D. Terentyev, Z. Kubalova, G. Valle, A. Nori, S. Vedamoorthyrao, R. Terentyeva, S. Viatchenko-Karpinski, D. M. Bers, S. C. Williams, P. Volpe, et al. Modulation of SR Ca Release by Luminal Ca and Calsequestrin in Cardiac Myocytes: Effects of CASQ2 Mutations Linked to Sudden Cardiac Death Biophys. J., August 15, 2008; 95(4): 2037 - 2048. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. A. Venetucci and D. A. Eisner Calsequestrin Mutations and Sudden Death: A Case of Too Little Sarcoplasmic Reticulum Calcium Buffering? Circ. Res., August 1, 2008; 103(3): 223 - 225. [Full Text] [PDF] |
||||
![]() |
N. Rizzi, N. Liu, C. Napolitano, A. Nori, F. Turcato, B. Colombi, S. Bicciato, D. Arcelli, A. Spedito, M. Scelsi, et al. Unexpected Structural and Functional Consequences of the R33Q Homozygous Mutation in Cardiac Calsequestrin: A Complex Arrhythmogenic Cascade in a Knock In Mouse Model Circ. Res., August 1, 2008; 103(3): 298 - 306. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y.-H. Yeh, R. Wakili, X.-Y. Qi, D. Chartier, P. Boknik, S. Kaab, U. Ravens, P. Coutu, D. Dobrev, and S. Nattel Calcium-Handling Abnormalities Underlying Atrial Arrhythmogenesis and Contractile Dysfunction in Dogs With Congestive Heart Failure Circ Arrhythmia Electrophysiol, June 1, 2008; 1(2): 93 - 102. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Qin, G. Valle, A. Nani, A. Nori, N. Rizzi, S. G. Priori, P. Volpe, and M. Fill Luminal Ca2+ Regulation of Single Cardiac Ryanodine Receptors: Insights Provided by Calsequestrin and its Mutants J. Gen. Physiol., March 31, 2008; 131(4): 325 - 334. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Yamamoto, M. Yano, X. Xu, H. Uchinoumi, H. Tateishi, M. Mochizuki, T. Oda, S. Kobayashi, N. Ikemoto, and M. Matsuzaki Identification of Target Domains of the Cardiac Ryanodine Receptor to Correct Channel Disorder in Failing Hearts Circulation, February 12, 2008; 117(6): 762 - 772. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Liu and S. G. Priori Disruption of calcium homeostasis and arrhythmogenesis induced by mutations in the cardiac ryanodine receptor and calsequestrin Cardiovasc Res, January 15, 2008; 77(2): 293 - 301. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. A. Venetucci, A. W. Trafford, S. C. O'Neill, and D. A. Eisner The sarcoplasmic reticulum and arrhythmogenic calcium release Cardiovasc Res, January 15, 2008; 77(2): 285 - 292. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Gyorke and D. Terentyev Modulation of ryanodine receptor by luminal calcium and accessory proteins in health and cardiac disease Cardiovasc Res, January 15, 2008; 77(2): 245 - 255. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. L. Reyes-Juarez, R. Juarez-Rubi, G. Rodriguez, and A. Zarain-Herzberg Transcriptional Analysis of the Human Cardiac Calsequestrin Gene in Cardiac and Skeletal Myocytes J. Biol. Chem., December 7, 2007; 282(49): 35554 - 35563. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Guo, X. Ai, T. R. Shannon, S. M. Pogwizd, and D. M. Bers Intra Sarcoplasmic Reticulum Free [Ca2+] and Buffering in Arrhythmogenic Failing Rabbit Heart Circ. Res., October 12, 2007; 101(8): 802 - 810. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Seidler, G. Hasenfuss, and L. S. Maier Targeting Altered Calcium Physiology in the Heart: Translational Approaches to Excitation, Contraction, and Transcription Physiology, October 1, 2007; 22(5): 328 - 334. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Terentyev, S. Viatchenko-Karpinski, S. Vedamoorthyrao, S. Oduru, I. Gyorke, S. C. Williams, and S. Gyorke Protein protein interactions between triadin and calsequestrin are involved in modulation of sarcoplasmic reticulum calcium release in cardiac myocytes J. Physiol., August 15, 2007; 583(1): 71 - 80. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. P. Dirksen, V. A. Lacombe, M. Chi, A. Kalyanasundaram, S. Viatchenko-Karpinski, D. Terentyev, Z. Zhou, S. Vedamoorthyrao, N. Li, N. Chiamvimonvat, et al. A mutation in calsequestrin, CASQ2D307H, impairs Sarcoplasmic Reticulum Ca2+ handling and causes complex ventricular arrhythmias in mice Cardiovasc Res, July 1, 2007; 75(1): 69 - 78. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. M. Faber and Y. Rudy Calsequestrin mutation and catecholaminergic polymorphic ventricular tachycardia: A simulation study of cellular mechanism Cardiovasc Res, July 1, 2007; 75(1): 79 - 88. [Abstract] [Full Text] [PDF] |
||||
![]() |
Q. Yuan, G.-C. Fan, M. Dong, B. Altschafl, A. Diwan, X. Ren, H. H. Hahn, W. Zhao, J. R. Waggoner, L. R. Jones, et al. Sarcoplasmic Reticulum Calcium Overloading in Junctin Deficiency Enhances Cardiac Contractility but Increases Ventricular Automaticity Circulation, January 23, 2007; 115(3): 300 - 309. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. R. di Barletta, S. Viatchenko-Karpinski, A. Nori, M. Memmi, D. Terentyev, F. Turcato, G. Valle, N. Rizzi, C. Napolitano, S. Gyorke, et al. Clinical Phenotype and Functional Characterization of CASQ2 Mutations Associated With Catecholaminergic Polymorphic Ventricular Tachycardia Circulation, September 5, 2006; 114(10): 1012 - 1019. [Abstract] [Full Text] [PDF] |
||||
|
Circulation Research Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search Copyright © 2006 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |