title: C-terminal splice variants of P/Q-type Ca2+channel CaV2.1 α1subunits are differentially regulated by Rab3-interacting molecule proteins.
abstract: Voltage-dependent Ca2+channels (VDCCs) mediate neurotransmitter release controlled by presynaptic proteins such as the scaffolding proteins Rab3-interacting molecules (RIMs). RIMs confer sustained activity and anchoring of synaptic vesicles to the VDCCs. Multiple sites on the VDCC α1and β subunits have been reported to mediate the RIMs-VDCC interaction, but their significance is unclear. Because alternative splicing of exons 44 and 47 in the P/Q-type VDCC α1subunit CaV2.1 gene generates major variants of the CaV2.1 C-terminal region, known for associating with presynaptic proteins, we focused here on the protein regions encoded by these two exons. Co-immunoprecipitation experiments indicated that the C-terminal domain (CTD) encoded by CaV2.1 exons 40-47 interacts with the α-RIMs, RIM1α and RIM2α, and this interaction was abolished by alternative splicing that deletes the protein regions encoded by exons 44 and 47. Electrophysiological characterization of VDCC currents revealed that the suppressive effect of RIM2α on voltage-dependent inactivation (VDI) was stronger than that of RIM1α for the CaV2.1 variant containing the region encoded by exons 44 and 47. Importantly, in the CaV2.1 variant in which exons 44 and 47 were deleted, strong RIM2α-mediated VDI suppression was attenuated to a level comparable with that of RIM1α-mediated VDI suppression, which was unaffected by the exclusion of exons 44 and 47. Studies of deletion mutants of the exon 47 region identified 17 amino acid residues on the C-terminal side of a polyglutamine stretch as being essential for the potentiated VDI suppression characteristic of RIM2α. These results suggest that the interactions of the CaV2.1 CTD with RIMs enable CaV2.1 proteins to distinguish α-RIM isoforms in VDI suppression of P/Q-type VDCC currents.
authors.affiliation: From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Hirano
authors.affiliation: From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Takada
authors.affiliation: From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and.|the Department of Biology, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjung Malim, Perak, Malaysia.
authors.forename: Chee Fah
authors.initials: CF
authors.lastname: Wong
authors.affiliation: From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kotani
authors.affiliation: From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and.
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Kurokawa
authors.affiliation: From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and.
authors.forename: Masayuki X
authors.initials: MX
authors.lastname: Mori
authors.affiliation: the Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada, and.
authors.forename: Terrance P
authors.initials: TP
authors.lastname: Snutch
authors.affiliation: the LabEx Ion Channels, Science and Therapeutics, INSERM UMR1087/CNRS UMR6291, Institut du Thorax, Université de Nantes, Nantes F-44000, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Ronjat
authors.affiliation: the LabEx Ion Channels, Science and Therapeutics, INSERM UMR1087/CNRS UMR6291, Institut du Thorax, Université de Nantes, Nantes F-44000, France.
authors.forename: Michel
authors.initials: M
authors.lastname: De Waard
authors.affiliation: From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and mori@sbchem.kyoto-u.ac.jp.|the Department of Technology and Ecology, Hall of Global Environmental Studies, Kyoto University, Kyoto 615-8510, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Mori
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D020864:Calcium Channels, N-Type / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D000072417:Protein Domains
chemical_list: D015220:Calcium Channels; D020864:Calcium Channels, N-Type; D019204:GTP-Binding Proteins; D009419:Nerve Tissue Proteins; C105656:CACNA1A protein, human; C491492:RIMS1 protein, human; C491490:Rims1 protein, mouse; C491491:Rims2 protein, mouse
keywords: Rab3-interacting molecule; alternative splicing; calcium channel; patch clamp; protein-protein interaction; synapse; voltage-dependent inactivation