2 SH2 DOMAINS OF P120 RAS GTPASE-ACTIVATING PROTEIN BIND SYNERGISTICALLY TO TYROSINE-PHOSPHORYLATED P190 RHO-GTPASE-ACTIVATING PROTEIN
2 SH2 DOMAINS OF P120 RAS GTPASE-ACTIVATING PROTEIN BIND SYNERGISTICALLY TO TYROSINE-PHOSPHORYLATED P190 RHO-GTPASE-ACTIVATING PROTEIN
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DOI：
10.1074/jbc.270.30.17947
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发表时间：
1995-07-28
影响因子：
4.8
通讯作者：
JOVE, R
中科院分区：
文献类型：
--
作者：
BRYANT, SS;BRIGGS, S;JOVE, R
p120 GTP酶激活蛋白（GAP）是Pas的负调节因子，在控制细胞增殖的信号转导途径中的关键中继点起作用。在其他蛋白质中，p120 GAP与p190相关，p190是PAS相关蛋白质Rho的GAP。为了表征p120。p190相互作用此外，我们使用细菌表达的谷胱甘肽S-转移酶融合多肽来绘制p120与p190相互作用所必需的区域。我们的研究结果表明，无论是N-末端和C-末端SH 2结构域的p120是单独能够结合p190在杆状病毒/昆虫细胞系统中表达。此外，两个SH 2结构域一起在一个多肽上协同结合p190，并且这种相互作用依赖于p190的酪氨酸磷酸化。此外，全长p120的两个SH 2结构域的关键FLVR序列中高度保守的Arg残基的突变减少了与酪氨酸磷酸化p190的结合。与p120形成复合物依赖于p190磷酸化。在体外观察到的SH 2结构域与天然p120的分析一致。p190复合物在体内形成。这些研究结果表明，SH 2-磷酸酪氨酸相互作用是细胞调节p120和p190协会的一种机制，因此可能是一种协调Ras和Rho介导的信号通路的手段。
p120 GTPase-activating protein (GAP) is a negative regulator of Pas that functions at a key relay point in signal transduction pathways that control cell proliferation. Among other proteins, p120 GAP associates with p190, a GAP for the Pas-related protein, Rho. To characterize the p120 . p190 interaction further, we used bacterially expressed glutathione S-transferase fusion polypeptides to map the regions of p120 necessary for its interactions with p190. Our results show that both the N-terminal and the C-terminal SH2 domains of p120 are individually capable of binding p190 expressed in a baculovirus/insect cell system. Moreover, the two SH2 domains together on one polypeptide bind synergistically to p190, and this interaction is dependent on tyrosine phosphorylation of p190. In addition, mutation of the highly conserved Arg residues in the critical FLVR sequences of both SH2 domains of full-length p120 reduces binding to tyrosine-phosphorylated p190. The dependence on p190 phosphorylation for complex formation with p120 . SH2 domains observed in vitro is consistent with analysis of the native p120 . p190 complexes formed in vivo. These findings suggest that SH2-phosphotyrosine interaction is one mechanism by which the cell regulates p120 p190 association and thus may be a means for coordinating the Ras- and Rho-mediated signaling pathways.