Ca2+ Dependent Phosphorylation of Bovine Aortic Actomyosin

Abstract

SummaryStudies of bovine aortic actomyosin employing isoelectric focusing and sodium dodecyl sulfate electrophoresis show Ca2+ dependent phosphorylation of 15,000 dalton polypeptides. These polypeptides probably correspond to the myosin light chains. The Ca2+ requirement for phosphorylation parallels the Ca2+ requirement for activation of Mg2+ stimulated actomyosin ATPase. These findings suggest that the Ca2+ regulatory mechanism for actin-myosin interactions in mammalian vascular smooth muscle may be partly mediated by phosphorylation of myosin light chains.