Cardiovascular Research Advance Access first published online on October 15, 2007
This version [Corrected Proof] published online on November 12, 2007
Cardiovascular Research, doi:10.1093/cvr/cvm038
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Modulation of ryanodine receptor by luminal calcium and accessory proteins in health and cardiac disease
Department of Physiology and Cell Biology, 505 Davis Heart and Lung Research Institute, The Ohio State University, 473 West 12th Avenue, Columbus, OH 43210, USA
* Corresponding author. Tel: +1 614 292 3969; fax: +1 614 247 7799. E-mail address: sandor.gyorke{at}osumc.edu
The cardiac ryanodine receptor (RyR2) is the sarcoplasmic reticulum (SR) Ca2+ release channel which is responsible for generation of the cytosolic Ca2+ transient required for activation of cardiac contraction. RyR2 functional activity is governed by changes in [Ca2+] on both the cytosolic and luminal phase of the RyR2 channel. Activation of RyR2 by cytosolic Ca2+ results in Ca2+-induced Ca2+ release (CICR) from the SR. The decline in luminal [Ca2+] following release contributes to termination of CICR and Ca2+ signalling refractoriness through the process of luminal Ca2+-dependent deactivation of RyR2s. The control of RyR2s by luminal Ca2+ involves coordinated interaction of the channel with several SR proteins, including the Ca2+-binding protein calsequestrin (CASQ2), and the integral proteins triadin 1 (TRD) and junctin (JCN). CASQ2 in addition to serving as a Ca2+ storage site and a luminal Ca2+ buffer modulates RyR2 function more directly as a putative luminal Ca2+ sensor. TRD and JCN, stimulatory by themselves, mediate the interactions between CASQ2 and RyR2. Acquired and genetic defects in proteins of this junctional Ca2+ signalling complex lead to disease states such as cardiac arrhythmia and heart failure by impairing luminal Ca2+ regulation of RyR2.
KEYWORDS Sacroplasmic reticulum; Ryanodine receptor; Calsequestrin; Calcium-induced calcium release
Time for primary review: 20 days
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