Activation of the cardiac Na(+)-Ca(2+) exchanger by sorcin via the interaction of the respective Ca(2+)-binding domains.

ABSTRACT: Sorcin is a penta-EF-hand protein that interacts with intracellular target proteins after Ca(2+) binding. The sarcolemmal Na(+)/Ca(2+) exchanger (NCX1) may be an important sorcin target in cardiac muscle. In this study, RNAi knockdown of sorcin, purified sorcin or sorcin variants was employed in parallel measurements of: (i) NCX activity in isolated rabbit cardiomyocytes using electrophysiological techniques and (ii) sorcin binding to the NCX1 calcium binding domains (CBD1 and (iii) using surface plasmon resonance and gel overlay techniques. Sorcin is activated by Ca(2+) binding to the EF3 and EF2 regions, which are connected by the D helix. To investigate the importance of this region in the interaction with NCX1, three variants were examined: W105G and W99G, mutated respectively near EF3

SUBMITTER: Zamparelli C 

PROVIDER: S-EPMC2958309 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature