REGULATION OF CALMODULIN-BINDING MYOSINS

Myosins constitute a diverse superfamily of actin-based mechanoenzymes that are involved in many essential cellular motilities. In addition to conventional muscle myosin II, ten other classes of unconventional myosins are known. Many unconventional myosins bind multiple calmoduli n light chains and Ca2+, which can dramatically alter their mechanoche mical and enzymatic activity. Calmodulin-binding myosins can also be r egulated by phospholipid binding, phosphorylation of the heavy chain a nd actin-binding proteins. The molecular details linking unconventiona l-myosin regulation and function are just beginning to emerge.