ASH/GRB-2, A SH2/SH3-CONTAINING PROTEIN, COUPLES TO SIGNALING FOR MITOGENESIS AND CYTOSKELETAL REORGANIZATION BY EGF AND PDGF
ASH/GRB-2, A SH2/SH3-CONTAINING PROTEIN, COUPLES TO SIGNALING FOR MITOGENESIS AND CYTOSKELETAL REORGANIZATION BY EGF AND PDGF
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DOI：
10.1002/j.1460-2075.1993.tb06021.x
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发表时间：
1993-09-01
期刊：
影响因子：
11.4
通讯作者：
TAKENAWA, T
中科院分区：
文献类型：
--
作者：
MATUOKA, K;SHIBASAKI, F;TAKENAWA, T
Src同源性（SH）区域2与磷酸化酪氨酸残基结合，SH3结构域可能与细胞骨架分子和Rho/Rac蛋白（与Ras相关的小gtp结合蛋白）的gtpase激活蛋白相互作用。最近克隆的Ash/Grb-2蛋白是一个完全由SH2和SH3结构域组成的25-28 kDa分子，是秀丽隐杆线虫Sem-5蛋白的哺乳动物同源物，该蛋白在受体蛋白酪氨酸激酶和Ras蛋白之间进行通信。本研究采用细胞微注射抗Ash抗体的方法研究了Ash/Grb-2的功能。在表皮生长因子（EGF）和血小板源性生长因子（PDGF）的刺激下，该抗体可阻止S期进入和肌动蛋白组装重组以形成皱褶。另一方面，抗ash抗体对血清和异磷酸酯酸诱导的S期进入和肌动蛋白应激纤维形成均无影响。由于诱导DNA合成、褶皱诱导和应激纤维形成分别涉及Ras、Rac激活和Rho激活的功能，因此研究结果强烈表明，Ash在从生长因子受体下游到Ras和Rac的两条通路的信号传导中起着关键作用。与此一致的是，Ash与EGF受体从EGF刺激的细胞中共沉淀。在抗Ash抗体免疫沉淀中还检测到约21、29、135和160 kDa的其他蛋白，提示Ash作为连接分子在生长因子受体下游的信号转导中起作用。
The Src homology (SH) region 2 binds to phosphorylated tyrosine residues and SH3 domains may interact with cytoskeletal molecules and GTPase-activating proteins for Rho/Rac proteins (the small GTP-binding proteins related to Ras). The recently cloned Ash/Grb-2 protein, a 25-28 kDa molecule composed entirely of SH2 and SH3 domains, is a mammalian homolog of the Caenorhabditis elegans Sem-5 protein, which communicates between a receptor protein tyrosine kinase and a Ras protein. In the present study the function of Ash/Grb-2 was investigated by microinjecting cells with an anti-Ash antibody. The antibody abolished both S phase entry and the reorganization of actin assembly to ruffle formation upon stimulation with epidermal growth factor (EGF) and platelet-derived growth factor (PDGF). On the other hand, anti-Ash antibody had no effect on S phase entry or actin stress fiber formation induced by either serum or tysophosphatidic acid. Since the induction of DNA synthesis, ruffle induction and stress fiber formation involve a function of Ras, Rac activation and Rho activation respectively, the findings strongly suggest that Ash plays a critical rote in the signaling of both pathways downstream from growth factor receptors to Ras and Rac. Consistent with this, Ash co-precipitated with EGF receptor from EGF-stimulated cells. Other proteins of approximately 21, 29, 135 and 160 kDa were also detected in the anti-Ash antibody immunoprecipitates, suggesting a role of Ash as a linker molecule in signal transduction downstream of growth factor receptors.