1996 Fiscal Year Annual Research Report

シナプスにおける新しいCa^<2+>センサーの機能と作用機構

Research Project

Project/Area Number	08270241
Research Institution	Osaka University
Principal Investigator	白瀧博通大阪大学, 医学部, 助手 (90249962)
Co-Investigator(Kenkyū-buntansha)	佐々木卓也大阪大学, 医学部, 助手 (40241278)
Keywords	神経伝達物質 / Rab3A / Rabphilin-3A / Doc2 / Ca^<2+>センサー / Rab GDI / Rob3 GAP
Research Abstract	私共の研究室では、C2領域を2個有する蛋白質としてRabphilin3とDoc2を見い出しており、Rabphilin3とDoc2が、シナプスにおいて新たなCa^<2+>センサーとして機能していることを明らかにしつつある。本研究で、私共は、Rabphilin3が少なくとも3つの異なる領域でシナプス小胞上の蛋白分子に結合してシナプス小胞に局在していることを明らかにした。さらに、Rabphilin3がα-アクチニンに結合し、α-アクチニンによるF-アクチンの重合を促進することを明らかにした。このことから、Rabphilin3が細胞骨格系をも介して神経伝達物質の放出反応を制御している可能性が高くなった。一方、Rabphiin3は、神経伝達物質の放出反応に関与している低分子量G蛋白質Rab3Aの標的蛋白質である。そこで、Rab3A-Rabphilin3系の作用機構を明らかにするために、本研究で、私共は、Rab3AのGTPase活性を促進する活性制御蛋白質Rab3 GAPをラット大脳より精製してその一次構造を決定した。Rab3 GAPは、C末端に翻訳後脂質修飾を受けたRab3Aを含むRab3ファミリー全てに作用しが、その他のRabには作用しなかった。さらに、私共は、Rab3A-Rab GDI複合体に作用してRab3AをRab GDIから解離させる活性制御蛋白質Rab3A GDFをラットのシナプス小胞膜画分において同定し、種々のカラムクロマトグラムにて高度に精製した。Rab3A GDFは、熱処理およびトリプシン処理にて失活する蛋白分子であった。このように、本研究は予想以上に進展し、当初の目的はほぼ完成に達成することができた。

Research Products

(17 results)

All Other

All Publications (17 results)

[Publications] Orita,S: "Doc2 enhances Ca^<2+>-dependent exocytosis from PC12 cells" J.Biol.Chem.271. 7257-7260 (1996)
[Publications] Fujita,Y.: "Phosphorylation of Munc-18/n-Secl/rbSecl by protein kinase C-Its implication in regulating the interaction of Munc-18/n-Secl/rbSecl with Syntaxin" J.Biol.Chem.271. 7265-7268 (1996)
[Publications] Shimizu,K.: "SMAP,an Smg GDS-associating protein having Arm repeats and phosphorylated by Src tyrosine kinase" J.Biol.Chem.271. 27013-27017 (1996)
[Publications] Kato,M.: "Physical and functional interaction of Rabphilin-3A with α-Actinin" J.Biol.Chem.271. 31775-31778 (1996)
[Publications] Hirao,M.: "Regulation mechanism of ERM(Ezrin/Radixin/Moesin)protein/plasma membrane association-Possible involvement of phosphatidylinositol turnover and Rho-dependent signaling pathway" J.Cell Biol.135. 37-51 (1996)
[Publications] Masumoto,N.: "Involvement of Rabphilin-3A in cortical granule exoctosis in mous eggs." J.Cell Biol.135. 1741-1747 (1996)
[Publications] Matsuda,S.: "A membrane-associated GDP/GTP exchange protein specific for Rho small GTP-binding protein-Partial purification and characterization from rat brain" Oncogene. 12. 915-920 (1996)
[Publications] Taniguchi,T.: "Cholecystokinin-B/gastrin receptors mediate rapid formation of actin stress fibers" Oncogene. 12. 1357-1360 (1996)
[Publications] Komuro,R.: "Involvement of rabphilin-3A in Ca^<2+>-dependent exocytosis from PC12 cells" Biochem.Biophys.Res.Commun.219. 435-440 (1996)
[Publications] Senbonmatsu,T.: "Interaction of Rbphilin3 with synaptic vesicles through multiple regions" Biochem.Biophys.Res.Commun.228. 567-572 (1996)
[Publications] Oishi,H.: "Interaction of both the C2A and C2B domains of rabphilin3 with Ca^<2+> and pospholipid" Biochem.Biophys.Res.Commun.229. 498-503 (1996)
[Publications] Komuro,R.: "Involvement of Rho and Rac small G proteins and Rho GDI in Ca^<2+>-dependent exocytosis from PC12 cells" Genes to Cells. 1. 943-951 (1996)
[Publications] Takai,Y.: "Rab3A small GTP-binding protein in Ca^<2+>-dependent exocytosis" Genes to Cells. 1. 615-632 (1996)
[Publications] Fukui,K.: "Isolation and characterization of a GTPase activating protein specific for the Rab3 subfamily of small G proteins" J.Biol.Chem.272. 4655-4658 (1997)
[Publications] Kotani,H.: "Rho regulates association of both the ERM family and vinculin with the plasma membrane in MDCK cells" Oncogene. (in press). (1997)
[Publications] Naito,A.: "Molecular cloning of mouse Doc2α and distribution of its mRNA in adult mouse brain" Mol.Brain.Res.(in press). (1997)
[Publications] Jin-no,Y.: "A novel function of the C-terminal lipid moieties of Rab3A small G protein implicated in Ca^<2+>-dependent exocytosis-Inhibition of interaction with GTP and reduction of this inhibition by phospholipid" Genes to Cells. (in press). (1997)

1996 Fiscal Year Annual Research Report

シナプスにおける新しいCa^<2+>センサーの機能と作用機構

Principal Investigator

白瀧 博通 大阪大学, 医学部, 助手 (90249962)

Research Products

[Publications] Orita,S: "Doc2 enhances Ca^<2+>-dependent exocytosis from PC12 cells" J.Biol.Chem.271. 7257-7260 (1996)

[Publications] Fujita,Y.: "Phosphorylation of Munc-18/n-Secl/rbSecl by protein kinase C-Its implication in regulating the interaction of Munc-18/n-Secl/rbSecl with Syntaxin" J.Biol.Chem.271. 7265-7268 (1996)

[Publications] Shimizu,K.: "SMAP,an Smg GDS-associating protein having Arm repeats and phosphorylated by Src tyrosine kinase" J.Biol.Chem.271. 27013-27017 (1996)

[Publications] Kato,M.: "Physical and functional interaction of Rabphilin-3A with α-Actinin" J.Biol.Chem.271. 31775-31778 (1996)

[Publications] Hirao,M.: "Regulation mechanism of ERM(Ezrin/Radixin/Moesin)protein/plasma membrane association-Possible involvement of phosphatidylinositol turnover and Rho-dependent signaling pathway" J.Cell Biol.135. 37-51 (1996)

[Publications] Masumoto,N.: "Involvement of Rabphilin-3A in cortical granule exoctosis in mous eggs." J.Cell Biol.135. 1741-1747 (1996)

[Publications] Matsuda,S.: "A membrane-associated GDP/GTP exchange protein specific for Rho small GTP-binding protein-Partial purification and characterization from rat brain" Oncogene. 12. 915-920 (1996)

[Publications] Taniguchi,T.: "Cholecystokinin-B/gastrin receptors mediate rapid formation of actin stress fibers" Oncogene. 12. 1357-1360 (1996)

[Publications] Komuro,R.: "Involvement of rabphilin-3A in Ca^<2+>-dependent exocytosis from PC12 cells" Biochem.Biophys.Res.Commun.219. 435-440 (1996)

[Publications] Senbonmatsu,T.: "Interaction of Rbphilin3 with synaptic vesicles through multiple regions" Biochem.Biophys.Res.Commun.228. 567-572 (1996)

[Publications] Oishi,H.: "Interaction of both the C2A and C2B domains of rabphilin3 with Ca^<2+> and pospholipid" Biochem.Biophys.Res.Commun.229. 498-503 (1996)

[Publications] Komuro,R.: "Involvement of Rho and Rac small G proteins and Rho GDI in Ca^<2+>-dependent exocytosis from PC12 cells" Genes to Cells. 1. 943-951 (1996)

[Publications] Takai,Y.: "Rab3A small GTP-binding protein in Ca^<2+>-dependent exocytosis" Genes to Cells. 1. 615-632 (1996)

[Publications] Fukui,K.: "Isolation and characterization of a GTPase activating protein specific for the Rab3 subfamily of small G proteins" J.Biol.Chem.272. 4655-4658 (1997)

[Publications] Kotani,H.: "Rho regulates association of both the ERM family and vinculin with the plasma membrane in MDCK cells" Oncogene. (in press). (1997)

[Publications] Naito,A.: "Molecular cloning of mouse Doc2α and distribution of its mRNA in adult mouse brain" Mol.Brain.Res.(in press). (1997)

[Publications] Jin-no,Y.: "A novel function of the C-terminal lipid moieties of Rab3A small G protein implicated in Ca^<2+>-dependent exocytosis-Inhibition of interaction with GTP and reduction of this inhibition by phospholipid" Genes to Cells. (in press). (1997)

白瀧博通大阪大学, 医学部, 助手 (90249962)