c-Src-mediated phosphorylation of the epidermal growth factor receptor on Tyr845 and Tyr1101 is associated with modulation of receptor function
c-Src-mediated phosphorylation of the epidermal growth factor receptor on Tyr845 and Tyr1101 is associated with modulation of receptor function
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DOI：
10.1074/jbc.274.12.8335
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发表时间：
1999-03-19
影响因子：
4.8
通讯作者：
Parsons, SJ
中科院分区：
文献类型：
--
作者：
Biscardi, JS;Maa, MC;Parsons, SJ
越来越多的证据表明，表皮生长因子受体（EGFR）和非受体酪氨酸激酶c-Src之间的相互作用可能有助于多种人类肿瘤的侵袭性表型。我们实验室先前的工作表明，与单一过表达者相比，过表达这两种酪氨酸激酶的鼠成纤维细胞在裸鼠中显示DNA合成、软琼脂生长和肿瘤形成的协同增加，以及受体底物Shc和磷脂酶γ的磷酸化增加。这些参数与c-Src和EGFR在体内形成EGF依赖性异源复合物的能力相关，在这里，我们提供的证据表明，c-Src和EGFR之间的关联可以直接发生，如受体覆盖实验所示，它导致在两个新的酪氨酸磷酸化的受体，在体外和体内EGF刺激后看到的外观。Edman降解分析和合成肽与EGFR衍生的胰蛋白酶磷酸肽的共迁移将这些位点鉴定为Tyr（845）和Tyr（1101）。Tyr（1101）位于受体自磷酸化位点之间的EGFR的羧基末端区域内，而Tyr 845位于催化结构域中，在类似于c-Src的Tyr（416）的位置。已显示Tyr（416）和其它酪氨酸激酶受体中的同源残基的磷酸化是催化活性所需的或增加催化活性，这表明c-Src可以通过介导Tyr（845）的磷酸化来影响EGFR活性。事实上，EGF诱导的Tyr（845）磷酸化在MDA 468人乳腺癌细胞工程改造过表达c-Src相比，亲本MDA 468细胞。此外，瞬时表达的Y845 F变体EGFR在鼠成纤维细胞中导致消融EGF诱导的DNA合成到非刺激水平。总之，这些数据支持c-Src介导的EGFR Tyr（845）磷酸化参与受体功能调节以及肿瘤进展的假设。
Accumulating evidence indicates that interactions between the epidermal growth factor receptor (EGFR) and the nonreceptor tyrosine kinase c-Src may contribute to an aggressive phenotype in multiple human tumors. Previous work from our laboratory demonstrated that murine fibroblasts which overexpress both these tyrosine kinases display synergistic increases in DNA synthesis, soft agar growth, and tumor formation in nude mice, and increased phosphorylation of the receptor substrates Shc and phospholipase gamma as compared with single overexpressors, These parameters correlated with the ability of c-Src and EGFR to form an EGF-dependent heterocomplex in vivo, Here we provide evidence that association between c-Src and EGFR can occur directly, as shown by receptor overlay experiments, and that it results in the appearance of two novel tyrosine phosphorylations on the receptor that are seen both in vitro and in vivo following EGF stimulation. Edman degradation analyses and co-migration of synthetic peptides with EGFR-derived tryptic phosphopeptides identify these sites as Tyr(845) and Tyr(1101). Tyr(1101) lies within the carboxyl-terminal region of the EGFR among sites of receptor autophosphorylation, while Tyr845 resides in the catalytic domain, in a position analogous to Tyr(416) Of c-Src, Phosphorylation of Tyr(416) and homologous residues in other tyrosine kinase receptors has been shown to be required for or to increase catalytic activity, suggesting that c-Src can influence EGFR activity by mediating phosphorylation of Tyr(845). Indeed, EGF-induced phosphorylation of Tyr(845) was increased in MDA468 human breast cancer cells engineered to overexpress c-Src as compared with parental MDA 468 cells. Furthermore, transient expression of a Y845F variant EGFR in murine fibroblasts resulted in an ablation of EGF-induced DNA synthesis to nonstimulated levels. Together, these data support the hypothesis that c-Src-mediated phosphorylation of EGFR Tyr(845) is involved in regulation of receptor function, as well as in tumor progression.