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signal transduction of small GTP binding proteins

小 GTP 结合蛋白的信号转导

基本信息

批准号：
03404022
负责人：
TAKAI Yoshimi
金额：
$ 20.22万
依托单位：
Kode University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

There is the small GTP- binding protein (G protein) superfamily which consists of over fiftu members. All members have monomeric proteins with Mrs between 20,000 and 30,000 which exhibit both GDP/GTO-binding and GTP ase activities. In the present research project, we studied the functions and modes of activation of small G proteins. Ras is the representative of this su perfamily and is well known to regulate cell proliferation, differentiation, and transformation, but its modes of activation and action remain to be clarified. We characterized three GDP/GTP exchange proteins for Ras including Smq GDS, CDC25Mm, and msos. We identified a target protein for Ras and named it REKS, which phosphorylated MAP kinase and thereby activated it in a Ras-dependent manner. Accumulating evidence suggests that Rho regulates certain functions through an actomyosin system. By use of C3 exoenzyme and Rho GDI, we showed that Rho regulated cell morphogy, cell motility, membrane ruffling, cy-tokinesis, and smooth muscle contraction through an actomyosin system. Red family is known to regulate intracellular vesicle transport, such as exocytosis, endocytosis, and transcytosis. Rab3A is a member of Rab family which is particularly implicated in neurotransmitter release from the synapse. We isolated the cDNA encoding a target protein for Rab3A, which selectively in-teracted with the GTP-bound form of Rab3A, and named it rabphilin-3A.

小GTP结合蛋白（G蛋白）超家族由五十多个成员组成.所有成员都具有Mrs在20，000和30，000之间的单体蛋白，其表现出GDP/GTO结合和GTP酶活性。本课题研究了小G蛋白的功能和激活方式。Ras是这一超家族的代表，并且众所周知其调节细胞增殖、分化和转化，但其激活和作用模式仍有待阐明。我们表征了Ras的三种GDP/GTP交换蛋白，包括Smq GDS，CDC 25 Mm和msos。我们确定了Ras的靶蛋白，并将其命名为REKS，它磷酸化MAP激酶，从而以Ras依赖的方式激活它。越来越多的证据表明，Rho通过肌动球蛋白系统调节某些功能。通过使用C3外切酶和Rho GDI，我们发现Rho通过肌动球蛋白系统调节细胞形态、细胞运动、膜皱褶、细胞分裂和平滑肌收缩。Red家族参与调节胞内囊泡的转运，如胞吐、胞吞和胞转。Rab 3A是Rab家族的成员，其特别涉及从突触释放神经递质。我们分离了编码Rab 3A的靶蛋白的cDNA，其选择性地与Rab 3A的GTP结合形式相互作用，并将其命名为rabphilin-3A。