title: Inositol 1, 4, 5-trisphosphate receptor interacts with the SNARE domain of syntaxin 1B.
abstract: Inositol 1, 4, 5-trisphosphate receptors (IP(3)Rs) are intracellular ligand-gated Ca(2+) channels that mediate Ca(2+) release from the endoplasmic reticulum (ER) into the cytosol and function in diverse cellular processes including fertilization, muscle contraction, apoptosis, secretion, and synaptic plasticity. The Ca(2+) release activity of IP(3)Rs is tightly regulated by many factors including IP(3)R-binding proteins. We show that IP(3)Rs interact with syntaxin 1 (Syx1), a membrane trafficking protein that regulates various plasma-membrane ion channels including N-, P/Q, and L-type voltage-gated Ca(2+) channels, voltage-gated potassium channels, and an epithelial sodium channel. We found that a SNARE-domain of Syx1B, one of the two Syx1 isoforms, directly interacted with the type1 IP(3)R (IP(3)R1) internal coupling domain, a known modulator for channel opening. These results indicate that Syx1B is an IP(3)R-interacting protein and that its interaction may play a crucial role in regulating the channel activity of IP(3)Rs in Syx1B-expressing cells.
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Tanaka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kabayama
authors.forename: Masahiro
authors.initials: M
authors.lastname: Enomoto
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Saito
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mikoshiba
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000737:chemistry / Q000378:metabolism*; D015640:Ion Channel Gating / Q000502:physiology; D007473:Ion Channels / Q000378:metabolism; D051379:Mice; D009154:Mutation; D016716:PC12 Cells; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D050600:SNARE Proteins / Q000737:chemistry* / Q000378:metabolism*; D050827:Syntaxin 1 / Q000737:chemistry / Q000378:metabolism*
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D007473:Ion Channels; D050600:SNARE Proteins; D050827:Syntaxin 1; D002118:Calcium