Myosin light chain phosphorylation enhances contraction of heart muscle via structural changes in both thick and thin filaments.

ABSTRACT: Contraction of heart muscle is triggered by calcium binding to the actin-containing thin filaments but modulated by structural changes in the myosin-containing thick filaments. We used phosphorylation of the myosin regulatory light chain (cRLC) by the cardiac isoform of its specific kinase to elucidate mechanisms of thick filament-mediated contractile regulation in demembranated trabeculae from the rat right ventricle. cRLC phosphorylation enhanced active force and its calcium sensitivity and altered thick filament structure as reported by bifunctional rhodamine probes on the cRLC: the myosin head domains became more perpendicular to the filament axis. The effects of cRLC phosphorylation on thick filament structure and its calcium sensitivity were mimicked by increasing sarcomere length or

SUBMITTER: Kampourakis T 

PROVIDER: S-EPMC4889392 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature