Abstract
To probe the physiological role of calsequestrin in excitation-contraction coupling, transgenic mice overexpressing cardiac calsequestrin were developed. Transgenic mice exhibited 10-fold higher levels of calsequestrin in myocardium and survived into adulthood, but had severe cardiac hypertrophy, with a twofold increase in heart mass and cell size. In whole cell-clamped transgenic myocytes, Ca2+ channel- gated Ca2+ release from the sarcoplasmic reticulum was strongly suppressed, the frequency of occurrence of spontaneous or Ca2+ current-triggered "Ca2+ sparks" was reduced, and the spark perimeter was less defined. In sharp contrast, caffeine-induced Ca2+ transients and the resultant Na+-Ca2+ exchanger currents were increased 10-fold in transgenic myocytes, directly implicating calsequestrin as the source of the contractile-dependent pool of Ca2+. Interestingly, the proteins involved in the Ca2+-release cascade (ryanodine receptor, junctin, and triadin) were downregulated, whereas Ca2+-uptake proteins (Ca2+-ATPase and phospholamban) were unchanged or slightly increased. The parallel increase in the pool of releasable Ca2+ with overexpression of calsequestrin and subsequent impairment of physiological Ca2+ release mechanism show for the first time that calsequestrin is both a storage and a regulatory protein in the cardiac muscle Ca2+-signaling cascade. Cardiac hypertrophy in these mice may provide a novel model to investigate the molecular determinants of heart failure.
Full Text
The Full Text of this article is available as a PDF (740.0 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Adachi-Akahane S., Cleemann L., Morad M. Cross-signaling between L-type Ca2+ channels and ryanodine receptors in rat ventricular myocytes. J Gen Physiol. 1996 Nov;108(5):435–454. doi: 10.1085/jgp.108.5.435. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Adachi-Akahane S., Lu L., Li Z., Frank J. S., Philipson K. D., Morad M. Calcium signaling in transgenic mice overexpressing cardiac Na(+)-Ca2+ exchanger. J Gen Physiol. 1997 Jun;109(6):717–729. doi: 10.1085/jgp.109.6.717. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brandt N. R., Caswell A. H., Brunschwig J. P., Kang J. J., Antoniu B., Ikemoto N. Effects of anti-triadin antibody on Ca2+ release from sarcoplasmic reticulum. FEBS Lett. 1992 Mar 24;299(1):57–59. doi: 10.1016/0014-5793(92)80100-u. [DOI] [PubMed] [Google Scholar]
- Cala S. E., Jones L. R. Rapid purification of calsequestrin from cardiac and skeletal muscle sarcoplasmic reticulum vesicles by Ca2+-dependent elution from phenyl-sepharose. J Biol Chem. 1983 Oct 10;258(19):11932–11936. [PubMed] [Google Scholar]
- Callewaert G., Cleemann L., Morad M. Caffeine-induced Ca2+ release activates Ca2+ extrusion via Na+-Ca2+ exchanger in cardiac myocytes. Am J Physiol. 1989 Jul;257(1 Pt 1):C147–C152. doi: 10.1152/ajpcell.1989.257.1.C147. [DOI] [PubMed] [Google Scholar]
- Cheng H., Lederer W. J., Cannell M. B. Calcium sparks: elementary events underlying excitation-contraction coupling in heart muscle. Science. 1993 Oct 29;262(5134):740–744. doi: 10.1126/science.8235594. [DOI] [PubMed] [Google Scholar]
- Cleemann L., Morad M. Role of Ca2+ channel in cardiac excitation-contraction coupling in the rat: evidence from Ca2+ transients and contraction. J Physiol. 1991 Jan;432:283–312. doi: 10.1113/jphysiol.1991.sp018385. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fleischer S., Inui M. Biochemistry and biophysics of excitation-contraction coupling. Annu Rev Biophys Biophys Chem. 1989;18:333–364. doi: 10.1146/annurev.bb.18.060189.002001. [DOI] [PubMed] [Google Scholar]
- Franzini-Armstrong C., Kenney L. J., Varriano-Marston E. The structure of calsequestrin in triads of vertebrate skeletal muscle: a deep-etch study. J Cell Biol. 1987 Jul;105(1):49–56. doi: 10.1083/jcb.105.1.49. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gulick J., Subramaniam A., Neumann J., Robbins J. Isolation and characterization of the mouse cardiac myosin heavy chain genes. J Biol Chem. 1991 May 15;266(14):9180–9185. [PubMed] [Google Scholar]
- Guo W., Jorgensen A. O., Jones L. R., Campbell K. P. Biochemical characterization and molecular cloning of cardiac triadin. J Biol Chem. 1996 Jan 5;271(1):458–465. doi: 10.1074/jbc.271.1.458. [DOI] [PubMed] [Google Scholar]
- Herrmann-Frank A., Lehmann-Horn F. Regulation of the purified Ca2+ release channel/ryanodine receptor complex of skeletal muscle sarcoplasmic reticulum by luminal calcium. Pflugers Arch. 1996 May;432(1):155–157. doi: 10.1007/s004240050117. [DOI] [PubMed] [Google Scholar]
- Ikemoto N., Antoniu B., Kang J. J., Mészáros L. G., Ronjat M. Intravesicular calcium transient during calcium release from sarcoplasmic reticulum. Biochemistry. 1991 May 28;30(21):5230–5237. doi: 10.1021/bi00235a017. [DOI] [PubMed] [Google Scholar]
- Ikemoto N., Ronjat M., Mészáros L. G., Koshita M. Postulated role of calsequestrin in the regulation of calcium release from sarcoplasmic reticulum. Biochemistry. 1989 Aug 8;28(16):6764–6771. doi: 10.1021/bi00442a033. [DOI] [PubMed] [Google Scholar]
- Jewett P. H., Sommer J. R., Johnson E. A. Cardiac muscle. Its ultrastructure in the finch and hummingbird with special reference to the sarcoplasmic reticulum. J Cell Biol. 1971 Apr;49(1):50–65. doi: 10.1083/jcb.49.1.50. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jones L. R., Besch H. R., Jr, Sutko J. L., Willerson J. T. Ryanodine-induced stimulation of net Ca++ uptake by cardiac sarcoplasmic reticulum vesicles. J Pharmacol Exp Ther. 1979 Apr;209(1):48–55. [PubMed] [Google Scholar]
- Jones L. R., Cala S. E. Biochemical evidence for functional heterogeneity of cardiac sarcoplasmic reticulum vesicles. J Biol Chem. 1981 Nov 25;256(22):11809–11818. [PubMed] [Google Scholar]
- Jones L. R., Zhang L., Sanborn K., Jorgensen A. O., Kelley J. Purification, primary structure, and immunological characterization of the 26-kDa calsequestrin binding protein (junctin) from cardiac junctional sarcoplasmic reticulum. J Biol Chem. 1995 Dec 22;270(51):30787–30796. doi: 10.1074/jbc.270.51.30787. [DOI] [PubMed] [Google Scholar]
- Kagari T., Yamaguchi N., Kasai M. Biochemical characterization of calsequestrin-binding 30-kDa protein in sarcoplasmic reticulum of skeletal muscle. Biochem Biophys Res Commun. 1996 Oct 23;227(3):700–706. doi: 10.1006/bbrc.1996.1572. [DOI] [PubMed] [Google Scholar]
- Kawasaki T., Kasai M. Regulation of calcium channel in sarcoplasmic reticulum by calsequestrin. Biochem Biophys Res Commun. 1994 Mar 30;199(3):1120–1127. doi: 10.1006/bbrc.1994.1347. [DOI] [PubMed] [Google Scholar]
- MacLennan D. H., Wong P. T. Isolation of a calcium-sequestering protein from sarcoplasmic reticulum. Proc Natl Acad Sci U S A. 1971 Jun;68(6):1231–1235. doi: 10.1073/pnas.68.6.1231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mitchell R. D., Simmerman H. K., Jones L. R. Ca2+ binding effects on protein conformation and protein interactions of canine cardiac calsequestrin. J Biol Chem. 1988 Jan 25;263(3):1376–1381. [PubMed] [Google Scholar]
- Mitra R., Morad M. A uniform enzymatic method for dissociation of myocytes from hearts and stomachs of vertebrates. Am J Physiol. 1985 Nov;249(5 Pt 2):H1056–H1060. doi: 10.1152/ajpheart.1985.249.5.H1056. [DOI] [PubMed] [Google Scholar]
- Movsesian M. A., Karimi M., Green K., Jones L. R. Ca(2+)-transporting ATPase, phospholamban, and calsequestrin levels in nonfailing and failing human myocardium. Circulation. 1994 Aug;90(2):653–657. doi: 10.1161/01.cir.90.2.653. [DOI] [PubMed] [Google Scholar]
- Puglisi J. L., Bassani R. A., Bassani J. W., Amin J. N., Bers D. M. Temperature and relative contributions of Ca transport systems in cardiac myocyte relaxation. Am J Physiol. 1996 May;270(5 Pt 2):H1772–H1778. doi: 10.1152/ajpheart.1996.270.5.H1772. [DOI] [PubMed] [Google Scholar]
- Scott B. T., Simmerman H. K., Collins J. H., Nadal-Ginard B., Jones L. R. Complete amino acid sequence of canine cardiac calsequestrin deduced by cDNA cloning. J Biol Chem. 1988 Jun 25;263(18):8958–8964. [PubMed] [Google Scholar]
- Sham J. S., Cleemann L., Morad M. Functional coupling of Ca2+ channels and ryanodine receptors in cardiac myocytes. Proc Natl Acad Sci U S A. 1995 Jan 3;92(1):121–125. doi: 10.1073/pnas.92.1.121. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sommer J. R. Comparative anatomy: in praise of a powerful approach to elucidate mechanisms translating cardiac excitation into purposeful contraction. J Mol Cell Cardiol. 1995 Jan;27(1):19–35. doi: 10.1016/s0022-2828(08)80004-1. [DOI] [PubMed] [Google Scholar]
- Tripathy A., Meissner G. Sarcoplasmic reticulum lumenal Ca2+ has access to cytosolic activation and inactivation sites of skeletal muscle Ca2+ release channel. Biophys J. 1996 Jun;70(6):2600–2615. doi: 10.1016/S0006-3495(96)79831-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yamaguchi N., Kawasaki T., Kasai M. DIDS binding 30-kDa protein regulates the calcium release channel in the sarcoplasmic reticulum. Biochem Biophys Res Commun. 1995 May 25;210(3):648–653. doi: 10.1006/bbrc.1995.1709. [DOI] [PubMed] [Google Scholar]
- Zhang L., Kelley J., Schmeisser G., Kobayashi Y. M., Jones L. R. Complex formation between junctin, triadin, calsequestrin, and the ryanodine receptor. Proteins of the cardiac junctional sarcoplasmic reticulum membrane. J Biol Chem. 1997 Sep 12;272(37):23389–23397. doi: 10.1074/jbc.272.37.23389. [DOI] [PubMed] [Google Scholar]