| Project/Area Number |
10044215
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neurochemistry/Neuropharmacology
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| Research Institution | SOPHIA UNIVERSITY |
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Principal Investigator |
KUMAKURA Konosuke Sophia University, Faculty of Science and Technology, Professor, 理工学部, 教授 (70129790)
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| Co-Investigator(Kenkyū-buntansha) |
MOCHIDA Sumiko Tokyo Medical College, Department of Pysiology, Associate Professor, 医学部, 助教授 (30096341)
KOZAKI Shunji Osaka Prefecture University, College of Agriculture, Professor, 農学部, 教授 (10109895)
TAKAHASHI Masami Mitsubishi Kasei Institute of Life Sciences, Project Center, Cheif, プロジェクトセンター, プロジェクトセンター長
IMAIZUMI Mica Sophia University, Faculty of Science and Technology, Assistant, 理工学部, 助手 (40201941)
SASAKAWA Nobuyuki Sophia University, Faculty of Science and Technology, Associate Professor, 理工学部, 助教授 (20187107)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥9,600,000 (Direct Cost: ¥9,600,000)
Fiscal Year 1999: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1998: ¥5,200,000 (Direct Cost: ¥5,200,000)
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| Keywords | Transmitter Release / Chromaffin Cell / Synaptotagmin / Inositol Polyphosphate / C Kinase / F-actin / RACK1 / SNARE Proteins / F.アクチン |
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| Research Abstract |
The aim of this research project is to elucidate the molecular mechanism of neurotransmitter release in collaboration with French group. The studies focused on 1) the mechanism of vesicle recruitment and priming, 2) the mechanism of fusion of vesicles in response to Ca^<2+> signals, and we have obtained the following results.
1. The mechanism of vesicle recruitment and priming.
1) We have suggested that binding of inositol polyphosphates to C2 domain of synaptotagmin acts as an inhibitory clamp for the exocytosis. We clarified that the bound inositol polyphosphates dissociate from synaptotagmin in response to Ca^<2+> in chromaffin cells. Microinjected inositol hexakisphosphate inhibited both the evoked and spontaneous exocytosis, while inositol hexakissulfate failed to inhibit.
2) We clarified that the subplasmalemmal actin network and actin-myosin interaction are essential for the vesicle recruitment and priming. We also found that the facilitation of the priming by protein kinase C (PKC) is mediated through the complex between the activated PKC α or PKC β, their receptor molecule RACK1 and cortical F-actin.
2. The mechanism of fusion of vesicles in response to Ca^<2+> signals.
1) Studies with subclones of PC12 cells demonstrated that the reduced expression of syntaxin, VAMP-2, SNAP-25 and Munc-18 decreased the exocytotic activity.
2) Studies on synaptic transmission clarified the recycle of SNARE proteins and binding of SNARE proteins with N-type Ca^<2+>-channels. It was also found that binding of Doc2 α to Munc13-1 precedes exocytosis.
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