Myosin I heavy chain kinase: Cloi acidic lipid-dependent activation

Acanthamoeba myosin I heavy chain kinase (MIHCK) phosphorylates the heavy chains of amoeba myo- sins I, increasing their actin-activated ATPase activities. The activity of MIHCK is increased by binding to acidic phospho- lipids or membranes and by autophosphorylation at multiple sites. Phosphorylation at a single site is necessary and suffi- cient for full activation of the expressed catalytic domain. The rate of autophosphorylation of native MIHCK is controlled by a region N-terminal to the catalytic domain. By its substrate specificity and the sequence of its C-terminal catalytic do-