Cloning and expression of a cardiac/brain beta subunit of the L-type calcium channel.
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.
Perez-Reyes
E
E
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030.
Castellano
A
A
Kim
H S
HS
Bertrand
P
P
Baggstrom
E
E
Lacerda
A E
AE
Wei
X Y
XY
Birnbaumer
L
L
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000502:physiology*; D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D003001:Cloning, Molecular / Q000379:methods; D015723:Gene Library; D006321:Heart / Q000502:physiology*; D007700:Kinetics; D046911:Macromolecular Substances; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D009132:Muscles / Q000502:physiology; D009838:Oligodeoxyribonucleotides; D009865:Oocytes / Q000502:physiology; D016133:Polymerase Chain Reaction; D051381:Rats; D011978:Receptors, Nicotinic / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D014162:Transfection; D014981:Xenopus
D015220:Calcium Channels; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D011978:Receptors, Nicotinic; D011994:Recombinant Proteins; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester