Ca 2+ Dependent Phosphorylation of Bovine Aortic Actomyosin 1

Abstract

Summary

Studies 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.