| Project/Area Number |
10480173
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional biochemistry
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| Research Institution | TOKYO METROPOLITAN ORGANIZATION FOR MEDICAL RESEARCH |
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Principal Investigator |
SANAI Yutaka Tokyo Metropolitan Institute of medical Science, Researcher, 東京都臨床医学総合研究所, 研究員 (40150289)
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| Co-Investigator(Kenkyū-buntansha) |
TAJIMA Youich Tokyo Metropolitan Institute of medical Science, Researcher, 東京都臨床医学総合研究所, 研究員 (00300955)
KASAHARA Kohji Tokyo Metropolitan Institute of medical Science, Researcher, 東京都臨床医学総合研究所, 研究員 (60250213)
星野 真人 財団法人 東京都医学研究機構, 東京都臨床医学総合研究所, 研究員 (40212196)
霜田 靖 財団法人東京都臨床医学総合研究所, 生命情報研究部門, 研究員 (00291154)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1999: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | ganglioside / tyrosine kinase / cell adhesion molecule / signal transduction / raft / caveolae / 生殖腺 |
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| Research Abstract |
The association of ganglioside GD3 with TAG-1, a glycosylphosphatidylinositol-anchored neuronal cell adhesion molecule, was examined by coimmunoprecipitation experiments. Previously, we have shown that the anti-ganglioside GD3 antibody (R24) immunoprecipitated the Src family kinase Lyn from the rat cerebellum, and R24 treatment of primary cerebellar cultures induced Lyn activation and rapid tyrosine phosphorylation of an 80-kDa protein (p80). We now report that R24 coimmunoprecipitates a 135-kDa protein (p135) from primary cerebellar cultures. Treatment with phosphatidylinositol-specitic phospholipase C revealed that p135 was glycosylphosphatidylinositol-anchored to the membrane. It was identified as TAG-1 by sequential immunoprecipitation with an anti-TAG-1 antibody. Antibody-mediated cross-linking of TAG-1 induced Lyn activation and rapid tyrosine phosphorylation of p80. Selective inhibitor for Src family kinases reduced the tyrosine phosphorylation of p80. Sucrose density gradient analysis revealed that the TAG-1 and tyrosine-phosphorylated p80 in cerebellar cultures were present in the lipid raft fraction. These data show that TAG-1 transduces signals via Lyn to p80 in the lipid rafts of the cerebellum. Furthermore, degradation of cell-surface glycosphingolipids by endoglycoceramidase induced an alteration of TAG-1 distribution on an OptiPrep gradient and reduced the TAG-1-mediated Lyn activation and tyrosine phosphorylation of p80. These observations suggest that glycosphingolipids are involved in TAG-1-mediated signaling in lipid rafts.
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