| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Institut für Pharmakologie und Toxikologie, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
2 Physiologisches Institut, Justus-Liebig-Universität Gießen, Gießen, Germany
3 Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
4 Dept. of Medicine and Biochemistry, Krannert Institute of Cardiology, Indianapolis, Indiana, United States
* To whom correspondence should be addressed. E-mail: ulrich.gergs{at}medizin.uni-halle.de.
Junctin is a transmembrane protein located at the cardiac junctional sarcoplasmic reticulum and forms a quaternary complex with the Ca2+ release channel, triadin and calsequestrin. Impaired protein interactions within this complex may alter the Ca2+ sensitivity of the Ca2+ release channel and may lead to cardiac dysfunction including hypertrophy, depressed contractility, and abnormal Ca2+ transients. To study the expression of junctin and for comparison triadin in heart failure, we measured the levels of these proteins in SR from normal and failing human hearts. Junctin was below our level of detection in SR membranes from failing human hearts, and triadin was downregulated by 22%. To better understand the role of junctin in the regulation of Ca2+ homeostasis and contraction of cardiac myocytes, we used an adenoviral approach to overexpress junctin in isolated rat cardiac myocytes. A recombinant adenovirus encoding the green fluorescent protein served as control. Infection of myocytes with the junctin-expressing virus resulted in an increased RNA and protein expression of junctin. Ca2+ transients showed a decreased maximum Ca2+ amplitude and contractility of myocytes was depressed. Our results demonstrate that an increased expression of junctin is associated with an impaired Ca2+ homeostasis. Downregulation of junctin in human heart failure may thus be a compensatory mechanism.
This article has been cited by other articles:
|
|
 |
|
  T. J. Pritchard and E. G. Kranias Junctin and the histidine-rich Ca2+ binding protein: potential roles in heart failure and arrhythmogenesis J. Physiol., July 1, 2009; 587(13): 3125 - 3133. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Chopra, T. Yang, P. Asghari, E. D. Moore, S. Huke, B. Akin, R. A. Cattolica, C. F. Perez, T. Hlaing, B. E. C. Knollmann-Ritschel, et al. Ablation of triadin causes loss of cardiac Ca2+ release units, impaired excitation-contraction coupling, and cardiac arrhythmias PNAS, May 5, 2009; 106(18): 7636 - 7641. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Q. Yuan, P. Han, M. Dong, X. Ren, X. Zhou, S. Chen, W. K. Jones, G. Chu, H.-S. Wang, and E. G. Kranias Partial downregulation of junctin enhances cardiac calcium cycling without eliciting ventricular arrhythmias in mice Am J Physiol Heart Circ Physiol, May 1, 2009; 296(5): H1484 - H1490. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Cheng and W. J. Lederer Calcium Sparks Physiol Rev, October 1, 2008; 88(4): 1491 - 1545. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Davis, M. V. Westfall, D. Townsend, M. Blankinship, T. J. Herron, G. Guerrero-Serna, W. Wang, E. Devaney, and J. M. Metzger Designing Heart Performance by Gene Transfer Physiol Rev, October 1, 2008; 88(4): 1567 - 1651. [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]
|
|
|
|
|
|
U. Kirchhefer, J. Klimas, H. A. Baba, I. B. Buchwalow, L. Fabritz, M. Huls, M. Matus, F. U. Muller, W. Schmitz, and J. Neumann Triadin is a critical determinant of cellular Ca cycling and contractility in the heart Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H3165 - H3174. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
