title: Identification of a cardiac isoform of the murine calcium channel alpha1C (Cav1.2-a) subunit and its preferential binding with the beta2 subunit.
abstract: 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.
authors.affiliation: Department of Pharmacology, Akita University School of Medicine, Akita 010-8543, Japan. manabumurakami@excite.co.jp
authors.forename: Manabu
authors.initials: M
authors.lastname: Murakami
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ohba
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Watanabe
authors.forename: Ichiro
authors.initials: I
authors.lastname: Miyoshi
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Nakayama
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Ono
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Iijima
mesh_terms: 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
chemical_list: C514350:CACNA1C protein, mouse; C491528:Cacnb2 protein, mouse; D020746:Calcium Channels, L-Type; D020033:Protein Isoforms; D021122:Protein Subunits