| Project/Area Number |
09044271
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Field |
Molecular biology
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| Research Institution | University of Tokyo |
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Principal Investigator |
HIRAI Hisamaru University of Tokyo Hospital, Internal Medicine, Associate Professor, 医学部附属病院, 助教授 (90181130)
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| Co-Investigator(Kenkyū-buntansha) |
KUROKAWA Mineo Research Fellow of the Japan Society for the Promotion of Science (University of, 医学部附属病院), 特別研究員
SASAKI Ko University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部附属病院, 助手 (60282638)
HONDA Hiroaki University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部附属病院, 助手 (40245064)
CHIBA Shigeru University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部附属病院, 助手 (60212049)
MITAMI Kinuko University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部附属病院, 助手 (50251244)
山形 哲也 日本学術振興会, 特別研究員
小川 誠司 東京大学, 医学部・附属病院, 助手
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥8,500,000 (Direct Cost: ¥8,500,000)
Fiscal Year 1998: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1997: ¥4,500,000 (Direct Cost: ¥4,500,000)
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| Keywords | Cas / SH3 / subcellular localization / focal adhesion / knockout mouse / myofibril / シグナル伝達 / チロシンリン酸化 |
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| Research Abstract |
p13OCas is an adapter protein that has an SH3 domain followed by multiple SH2 binding motifs in the substrate domain. It also contains a tyrosine residue and a proline-rich sequence near the C terminus, which are the binding sites for the SH2 and SH3 domains of Src kinase, respectively. Cas was shown to be inducibly tyrosine phosphorylated upon integrin stimulation. We examined the subcellular localization of Gas and determined the regions required for its localization to focal adhesions. In nontransformed cells, Cas was localized predominantly to the cytoplasm and partially to focal adhesions. However, in 527F-c-Src-transformed cells, Gas was localized mainly to podosomes. The localization of Cas to focal adhesions was observed in cells expressing the kinase-negative 527F/295M-c-Src. The SH3 domain of Cas is necessary for its localization to focal adhesions in nontransformed cells while both the SH3 domain and the C-terminal Src binding domain of Cas are required in 527F-c-Src-transfo
… More
rmed cells and fibronectin-stimulated cells. In addition, the localization of Gas to focal adhesions was abolished in Src-negative cells. These results demonstrate that the SH3 domain of Cas and the association of Cas with Src kinase play a pivotal role in the localization of Gas to focal adhesions. To determine its role in vivo, we generated mice lacking Gas. Gas-deficient embryos died in utero showing marked systemic congestion and growth retardation. Histologically, the heart was poorly developed and blood vessels were prominently dilated. Electron microscopic analysis of the heart revealed disorganization of myofibrils and disruption of Z-disks. In addition, actin stress fiber formation was severely impaired in Cas-deficient primary fibroblasts. Moreover, expression of activated Src in Cas-deficient primary fibroblasts did not induce a fully transformed phenotype, possibly owing to insufficient accumulation of actin cytoskeleton in podosomes. These findings have defined Gas function in cardiovascular development, actin filament assembly and Src-induced transformation. Less
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