regulatory actions of calmodulin on the contractile apparatus and cytoskeleton of smooth muscle and nonmuscle tissue are mediated by a number of specific calmodulin-binding proteins that bind to f-actin in a flip-flop manner -- i.e. , they bind to calmodulin or f-actin depending on the presence or absence , respectively , of ca2+ .
C0010853
cytoskeleton
C1180307
f-actin