Src and Pyk2 mediate G-protein-coupled receptor activation of epidermal growth factor receptor (EGFR) but are not required for coupling to the mitogen-activated protein (MAP) kinase signaling cascade
Src and Pyk2 mediate G-protein-coupled receptor activation of epidermal growth factor receptor (EGFR) but are not required for coupling to the mitogen-activated protein (MAP) kinase signaling cascade
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DOI：
10.1074/jbc.m102307200
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发表时间：
2001-06-08
影响因子：
4.8
通讯作者：
Schlessinger, J
中科院分区：
文献类型：
--
作者：
Andreev, J;Galisteo, ML;Schlessinger, J
表皮生长因子受体（EGFR）和非受体蛋白酪氨酸激酶Src和Pyk2参与了多种g蛋白偶联受体（GPCR）与丝裂原活化蛋白（MAP）激酶信号级联的连接。在本报告中，我们采用了一种遗传策略，使用从Src-、Pyk2-或EGFR缺陷小鼠中分离的细胞来探索这些蛋白酪氨酸激酶在gpcr诱导的EGFR、Pyk2和MAP激酶激活中所起的作用。我们发现Src激酶对于响应gpcr刺激的Pyk2激活至关重要，Pyk2和Src对于gpcr诱导的EGFR酪氨酸磷酸化至关重要，相比之下，Pyk2、Src和EGFR对于gpcr诱导的MAP激酶激活是必不可少的。此外，gpcr诱导的MAP激酶激活在Src和Pyk2缺陷的成纤维细胞（Src-/-Pyk2-/-细胞）以及在这些细胞中表达的所有三种Src激酶缺陷的成纤维细胞（Src-/- - - -/- fyn -/-细胞）中是正常的。最后，实验表明，在GPCR的刺激下，活化的Pyk2与Src形成复合物，进而直接磷酸化EGFR。这些实验揭示了Src激酶在Pyk2激活中的作用，以及Pyk2和Src在GPCR刺激后EGFR酪氨酸磷酸化中的作用。此外，EGFR、Src家族激酶和Pyk2不是连接GPCR与MAP激酶信号级联所必需的。
The epidermal growth factor receptor (EGFR) and the non-receptor protein tyrosine kinases Src and Pyk2 have been implicated in linking a variety of G-protein-coupled receptors (GPCR) to the mitogen-activated protein (MAP) kinase signaling cascade. In this report we apply a genetic strategy using cells isolated from Src-, Pyk2-, or EGFR-deficient mice to explore the roles played by these protein tyrosine kinases in GPCR-induced activation of EGFR, Pyk2, and MAP kinase. We show that Src kinases are critical for activation of Pyk2 in response to GPCR-stimulation and that Pyk2 and Src are essential for GPCR-induced tyrosine phosphorylation of EGFR, By contrast, Pyk2, Src, and EGFR are dispensable for GPCR-induced activation of MAP kinase. Moreover, GPCR-induced MAP kinase activation is normal in fibroblasts deficient in both Src and Pyk2 (Src-/-Pyk2-/- cells) as well as in fibroblasts deficient in all three Src kinases expressed in these cells (Src-/-Yes-/-Fyn-/- cells). Finally, experiments are presented demonstrating that, upon stimulation of GPCR, activated Pyk2 forms a complex with Src, which in turn phosphorylates EGFR directly. These experiments reveal a role for Src kinases in Pyk2 activation and a role for Pyk2 and Src in tyrosine phosphorylation of EGFR following GPCR stimulation, In addition, EGFR, Src family kinases, and Pyk2 are not required for linking GPCRs with the MAP kinase signaling cascade.