Cloning and expression of a third calcium channel beta subunit.
The skeletal muscle dihydropyridine receptor/Ca2+ channel consists of five distinct subunits (alpha 1, alpha 2 delta, beta 1, and gamma). Homologous alpha 1, alpha 2 delta, and beta 2 subunits are expressed in heart and brain. The present study reports the cloning and expression of a third beta subunit, beta 3, which is expressed predominantly in brain. Its open reading frame encodes a protein with 484 amino acids with a predicted molecular mass of 54,571 Da. Coexpression of beta 3 with a cardiac alpha 1 in Xenopus oocytes induces similar changes in Ca2+ channel activity as beta 1 and beta 2, that is, it increases peak currents, modulates the voltage dependence of activation, and accelerates activation. In addition, beta 3 accelerates the rate of inactivation at positive test potentials.
Castellano
A
A
Department of Molecular Physiology, Baylor College of Medicine, Houston, Texas 77030.
Wei
X
X
Birnbaumer
L
L
Perez-Reyes
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000502:physiology*; D015220:Calcium Channels / Q000235:genetics* / Q000502:physiology*; D047388:Casein Kinases; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D015723:Gene Library; D006321:Heart / Q000502:physiology*; D007700:Kinetics; D046911:Macromolecular Substances; D008297:Male; D008969:Molecular Sequence Data; D009132:Muscles / Q000502:physiology*; D009838:Oligodeoxyribonucleotides; D009865:Oocytes / Q000502:physiology*; D009928:Organ Specificity; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods; D011493:Protein Kinase C / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014981:Xenopus
D015220:Calcium Channels; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D004247:DNA; D011494:Protein Kinases; D047388:Casein Kinases; D011493:Protein Kinase C