Maa M C, Leu T H
Institute of Biochemistry, Chung Shan Medical and Dental College, Taichung, Taiwan, Republic of China.
Biochem Biophys Res Commun. 1998 Oct 9;251(1):344-9. doi: 10.1006/bbrc.1998.9464.
Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase implicated in cell-matrix interaction and integrin signaling. It is well established that Tyr-397 is the FAK autophosphorylation site and Tyr-407, -576/577, -861, and -925 are the sites on murine FAK that are mediated by Src family kinases. To study how FAK is regulated by tyrosine phosphatase(s), cells overexpressing chicken FAK are treated with sodium vanadate. Both the phosphotyrosine content and the enzymatic activity of FAK are increased in response to vanadate. Interestingly, sustained FAK Tyr-576/577 and -863 phosphorylations are detected in vanadate-treated FAK overexpressors and are dependent on FAK autophosphorylation. Further analysis of sodium vanadate-treated FAK overexpressors reveals that the enhanced FAK kinase activity parallels its elevated Tyr-576/577 phosphorylation. Thus, we conclude that Src-mediated FAK phosphorylation is regulated by a tyrosine phosphatase(s) and may be of physioligical significance.
粘着斑激酶（FAK）是一种非受体酪氨酸激酶，参与细胞与基质的相互作用和整合素信号传导。众所周知，Tyr-397是FAK的自磷酸化位点，而Tyr-407、-576/577、-861和-925是小鼠FAK上由Src家族激酶介导的位点。为了研究FAK如何被酪氨酸磷酸酶调节，用钒酸钠处理过表达鸡FAK的细胞。钒酸钠处理后，FAK的磷酸酪氨酸含量和酶活性均增加。有趣的是，在钒酸钠处理的FAK过表达细胞中检测到持续的FAK Tyr-576/577和-863磷酸化，且依赖于FAK自磷酸化。对钒酸钠处理的FAK过表达细胞的进一步分析表明，增强的FAK激酶活性与其升高的Tyr-576/577磷酸化水平平行。因此，我们得出结论，Src介导的FAK磷酸化受酪氨酸磷酸酶调节，可能具有生理意义。
