. "The skeletal muscle dihydropyridine receptor/Ca2+ channel is composed of five protein components (alpha 1, alpha 2 delta, beta, and gamma). Only two such components, alpha 1 and alpha 2, have been identified in heart. The present study reports the cloning and expression of a novel beta gene that is expressed in heart, lung, and brain. Coexpression of this beta with a cardiac alpha 1 in Xenopus oocytes causes the following changes in Ca2+ channel activity: it increases peak currents, accelerates activation kinetics, and shifts the current-voltage relationship toward more hyperpolarized potentials. It also increases dihydropyridine binding to alpha 1 in COS cells. These results indicate that the cardiac L-type Ca2+ channel has a similar subunit structure as in skeletal muscle, and provides evidence for the modulatory role of the beta subunit." . . . "J. Biol. Chem." . "Birnbaumer L." . "Bertrand P." . "Perez-Reyes E." . "Castellano A." . "Kim H.S." . "Baggstrom E." . "Lacerda A.E." . "Wei X.Y." . "1992"^^ . "1792-1797" . "Cloning and expression of a cardiac/brain beta subunit of the L-type calcium channel." . "267" .