title: DHP-insensitive L-type-like Ca channel of ascidian acquires sensitivity to DHP with single amino acid change in domain III P-region.
abstract: TuCa1, an ascidian homolog of L-type Ca channel alpha(1)-subunit, has many critical sites required for binding 1,4-dihydropyridines (DHPs), but is insensitive to DHPs and methyl 2,5-dimethyl-4-[2-(phenylmethyl)benzoyl]-1H-pyrrole-3-carboxylate (FPL-64176). We have substituted Ser for Ala(1016) at the P-region of domain III in TuCa1 (TuCa1/A1016S) and functionally expressed the channel in Xenopus oocyte along with rabbit alpha(2)/delta and beta(2b). TuCa1/A1016S has gained DHP sensitivity as high as that of a mammalian neuronal L-type Ca channel (rbCII), but remained resistant to FPL-64176. These results reinforce the view that Ser(1016) in TuCa1/A1016S participates in DHP binding, but there exist other novel sites that fully acquire sensitivity to FPL-64176.
authors.affiliation: Advanced Medical Science, the Institute of Medical Science, the University of Tokyo, 4-6-1 Shirokanedai, Minato 108-8639, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Izumi-Nakaseko
authors.forename: Shinji
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ohtsuka
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Ebihara
authors.forename: Satomi
authors.initials: S
authors.lastname: Adachi-Akahane
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okamura
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001464:Barium / Q000378:metabolism; D001483:Base Sequence; D020746:Calcium Channels, L-Type / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D004095:Dihydropyridines / Q000494:pharmacology*; D004594:Electrophysiology; D006801:Humans; D007814:Larva / Q000737:chemistry; D008322:Mammals / Q000235:genetics; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D014561:Urochordata / Q000737:chemistry
chemical_list: D020746:Calcium Channels, L-Type; D004095:Dihydropyridines; C419385:L-type calcium channel alpha(1C); D021122:Protein Subunits; D001464:Barium; C038806:1,4-dihydropyridine