Murakami Manabu, Ohba Takayoshi, Takahashi Yoichiro, Watanabe Hiroyuki, Miyoshi Ichiro, Nakayama Shinsuke, Ono Kyoichi, Ito Hiroshi, Iijima Toshihiko
Department of Pharmacology, Akita University School of Medicine, Akita 010-8543, Japan.
J Mol Cell Cardiol. 2006 Jul;41(1):115-25. doi: 10.1016/j.yjmcc.2006.05.002. Epub 2006 Jun 19.
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.
我们描述了一种电压依赖性钙通道α1亚基的心肌亚型，它对应于兔α1C-a（Cav1.2a）的直系同源物。我们还克隆了平滑肌亚型α1C-b（Cav1.2b）和α1C-d（Cav1.2d）。这三种亚型之间的差异存在于N端区域（外显子1A或1B）、结构域I的第六个跨膜片段（外显子8A或8B）以及外显子10的使用上，外显子10形成跨膜结构域I和II之间的细胞内环。双杂交分析揭示了三种α1亚型与β亚基之间的相互作用。体外覆盖和免疫沉淀分析显示α1C-a与β2之间存在优先结合，β2在心脏中也高水平表达。
