Identification of a cardiac isoform of the murine calcium channel alpha1C (Cav1.2-a) subunit and its preferential binding with the beta2 subunit.
We describe a cardiac muscle isoform of the voltage-dependent calcium channel alpha1 subunit, which corresponds to the rabbit ortholog of alpha1C-a (Cav1.2a). We also cloned smooth muscle isoforms alpha1C-b (Cav1.2b) and alpha1C-d (Cav1.2d). Differences among these three isoforms lie within the N-terminal region (exon 1A or 1B), the sixth transmembrane segment of domain I (exon 8A or 8B), and the use of exon 10, which forms the intracellular loop between transmembrane domains I and II. Two-hybrid analysis revealed interactions among the three alpha1 isoforms and beta subunits. In vitro overlay and immunoprecipitation analyses revealed preferential binding between alpha1C-a and beta2, which is also expressed at a high level in the heart.
Murakami
Manabu
M
Department of Pharmacology, Akita University School of Medicine, Akita 010-8543, Japan. manabumurakami@excite.co.jp
Ohba
Takayoshi
T
Takahashi
Yoichiro
Y
Watanabe
Hiroyuki
H
Miyoshi
Ichiro
I
Nakayama
Shinsuke
S
Ono
Kyoichi
K
Ito
Hiroshi
H
Iijima
Toshihiko
T
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000378:metabolism*; D005091:Exons; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
C514350:CACNA1C protein, mouse; C491528:Cacnb2 protein, mouse; D020746:Calcium Channels, L-Type; D020033:Protein Isoforms; D021122:Protein Subunits