Deb T B, Wong L, Salomon D S, Zhou G, Dixon J E, Gutkind J S, Thompson S A, Johnson G R
Division of Cytokine Biology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA.
J Biol Chem. 1998 Jul 3;273(27):16643-6. doi: 10.1074/jbc.273.27.16643.
The ErbB family of receptors, which include the epidermal growth factor receptor (EGFR), ErbB2, ErbB3, and ErbB4 mediate the actions of a family of bioactive polypeptides. EGF signals through EGFR, whereas heregulin (HRG) signaling is initiated through binding to either ErbB3 or ErbB4. In this report we studied the role of protein-tyrosine phosphatase SHP-2 in ErbB-mediated activation of mitogen-activated protein kinase (MAPK) by overexpressing SHP-2 mutants in COS-7 cells. We demonstrate that enzymatic activity and both NH2- and COOH-terminal SH2 domains of SHP-2 are required for EGF-induced MAPK activation, but not for c-Jun amino-terminal kinase stimulation or MAPK activation which occurred in response to myristoylated son of sevenless, activated Ras, or phorbol ester. Dominant-negative forms of SHP-2 had no effect on EGF-stimulated interaction of GRB2 with EGFR or SHC, nor did they influence phosphorylation of SHC and SHC/EGFR association. The same mutant SHP-2 structures that inhibited EGF-mediated stimulation of MAPK also blocked HRG alpha/beta-induced MAPK activation. EGF or HRG beta caused SHP-2 SH2 domains to engage multiple phosphotyrosine proteins, and mutation of either domain disrupted these associations. These results demonstrate that SHP-2 performs a common and essential function(s) in ligand-stimulated MAPK activation by the ErbB family of receptors.
受体酪氨酸激酶ErbB家族包括表皮生长因子受体(EGFR)、ErbB2、ErbB3和ErbB4,介导一类生物活性多肽的作用。表皮生长因子(EGF)通过EGFR发出信号,而这里的神经调节蛋白(HRG)信号则通过与ErbB3或ErbB4结合启动。在本报告中,我们通过在COS-7细胞中过表达SHP-2突变体,研究了蛋白酪氨酸磷酸酶SHP-2在ErbB介导的丝裂原活化蛋白激酶(MAPK)激活中的作用。我们证明,SHP-2的酶活性以及其氨基末端和羧基末端的SH2结构域是EGF诱导的MAPK激活所必需的,但对于c-Jun氨基末端激酶的刺激或响应豆蔻酰化的七号缺失蛋白(mSos)、活化的Ras或佛波酯而发生的MAPK激活并非必需。SHP-2的显性负性形式对EGF刺激的GRB2与EGFR或SHC的相互作用没有影响,也不影响SHC的磷酸化以及SHC/EGFR的结合。抑制EGF介导的MAPK刺激的相同突变SHP-2结构也阻断了HRGα/β诱导的MAPK激活。EGF或HRGβ导致SHP-2的SH2结构域与多种磷酸化酪氨酸蛋白结合,任何一个结构域的突变都会破坏这些结合。这些结果表明,SHP-2在ErbB家族受体介导的配体刺激的MAPK激活中发挥共同且必不可少的功能。