Title: Cloning and expression of a cardiac/brain beta subunit of the L-type calcium channel.

Authors: E Perez-Reyes, A Castellano, H S Kim, P Bertrand, E Baggstrom, A E Lacerda, X Y Wei, L Birnbaumer

Journal, date & volume: J. Biol. Chem., 1992 Jan 25 , 267, 1792-7

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/1370480

Abstract
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.