title: Hetero-oligomerization of C2 domains of phospholipase C-related but catalytically inactive protein and synaptotagmin-1.
abstract: The C2 domain is a protein module often found in molecules that regulate exocytosis. C2 domains mediate interactions between the parental molecule and Ca(2+), phospholipids, and proteins. Although various molecules have been shown to interact with several C2 domains, no interactions between the C2 domains from different molecules have yet been reported. In the present study, we identified direct interactions between the C2 domain of PRIP (phospholipase C-related but catalytically inactive protein) and the C2 domains of other molecules. Among the C2 domains examined, those of synaptotagmin-1 (Syt1-C2A and Syt1-C2B) and phospholipase C δ-1 bound to the C2 domain of PRIP. We investigated the interactions between the C2 domain of PRIP (PRIP-C2) with Syt1-C2A and Syt1-C2B, and the mode of binding of each was Ca(2+)-dependent and -independent, respectively. We further demonstrated that the Ca(2+) dependence of the interaction between PRIP-C2 and Syt1-C2A was attributed to Ca(2+) binding with Syt1-C2A, but not PRIP-C2, using a series of mutants prepared from both C2 domains. We previously reported that the interaction between PRIP-C2 and the membrane fusion machinery suggested a critical role for PRIP in exocytosis; therefore, the results of the present study further support the importance of PRIP-C2 in the inhibitory function of PRIP in regulating exocytosis.
authors.affiliation: Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Fukuoka 812-8582, Japan.
authors.forename: DaGuang
authors.initials: D
authors.lastname: Wang
authors.affiliation: Division of Applied Pharmacology, Kyushu Dental University, Kitakyushu 803-8580, Japan. Electronic address: r12takeuchi@fa.kyu-dent.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takeuchi
authors.affiliation: Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Fukuoka 812-8582, Japan.
authors.forename: Jing
authors.initials: J
authors.lastname: Gao
authors.affiliation: Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Fukuoka 812-8582, Japan; Stomatological Hospital of Hebei Medical University, Shijiazhuang 050017, PR China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Laboratory of Molecular and Cellular Biochemistry, Faculty of Dental Science, Fukuoka 812-8582, Japan. Electronic address: hirata1@dent.kyushu-u.ac.jp.
authors.forename: Masato
authors.initials: M
authors.lastname: Hirata
mesh_terms: D000818:Animals; D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology; D051379:Mice; D054803:Phospholipase C delta / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins; D050863:Synaptotagmin I / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D050863:Synaptotagmin I; C494311:Syt1 protein, mouse; D054803:Phospholipase C delta; C518025:Plcd1 protein, mouse; D002118:Calcium
keywords: C2 domain; Rabphiline; SNAP-25; SNARE; Synaptotagmin; Syntaxin