Calmodulin and excitation-contraction coupling

Excitation-contraction coupling in cardiac and skeletal muscle involves the transverse-tubule voltage-dependent Ca2+ channel and the sarcoplasmic reti culum Ca2+ release channel Both of these ion channels bind and are modulate d by calmodulin in both ifs Ca2+-bound and Ca2+-free forms. Calmodulin is, therefore, potentially an important regulator of excitation-contraction cou pling. Ifs precise role, however, has not yet been defined.