Bridging the myoplasmic gap: recent developments in skeletal muscle excitation-contraction coupling

Conformational coupling between the L-type voltage-gated Ca2+ channel (or 1,4-dihydropyridine receptor; DHPR) and the ryanodine-sensitive Ca2+ release channel of the sarcoplasmic reticulum (RyR1) is the mechanistic basis for excitation-contraction (EC) coupling in skeletal muscle. In this article, recent findings regarding the roles of the individual cytoplasmic domains (the amino- and carboxyl-termini, cytoplasmic loops I-II, II-III, and III-IV) of the DHPR alpha(1S) subunit in bi-directional communication with RyR1 will be discussed.