Regulation of cardiac and smooth muscle Ca2+ channels (Ca(V)1.2a,b) by protein kinases

High voltage-activated Ca2+ channels of the Ca(V)1.2 class (L-type) are cru cial for excitation-contraction coupling in both cardiac and smooth muscle. These channels are regulated by a variety of second messenger pathways tha t ultimately serve to modulate the level of contractile force in the tissue . The specific focus of this review is on the most recent advances in our u nderstanding of how cardiac Ca(V)1.2a and smooth muscle Ca(V)1.2b channels are regulated by different kinases, including cGMP-dependent protein kinase , cAMP-dependent protein kinase, and protein kinase C. This review also dis cusses recent evidence regarding the regulation of these channels by protei n tyrosine kinase, calmodulin-dependent kinase, purified G protein subunits , and identification of possible amino acid residues of the channel respons ible for kinase regulation.