Kameda H, Risinger J I, Han B B, Baek S J, Barrett J C, Glasgow W C, Eling T E
Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina 27709, USA.
Cell Growth Differ. 2001 Jun;12(6):307-18.
The adaptor protein Grb2-associated binder-1 (Gab1) is known to bind to the SHP-2 tyrosine phosphatase on epidermal growth factor (EGF) receptor stimulation. To clarify the roles of these two proteins in EGF receptor (EGFR) signaling and determine their possible alteration during neoplastic cell progression, we studied these proteins in a Syrian hamster embryo (SHE) cell line model of neoplastic progression. Specifically, we used asbestos-transformed SHE fibroblasts: the 10W+8 clone, which is immortal but nontumorigenic; and the 10W2T clone, which is tumorigenic. Gab1 was detected, and the EGF-dependent formation of the EGFR-Gab1-SHP-2 complex was observed in 10W+8 cells. After cloning hamster Gab1 cDNA, exogenous expression of Gab1 significantly enhanced EGF-dependent mitogenic activity in 10W+8 cells. On the other hand, Gab1 was not detected in 10W2T cells, and the EGF-dependent association of SHP-2 with EGFR was also absent. Exogenous Gab1 expression in transfected 10W2T cells restored the EGF-dependent association of SHP-2 with EGFR, although it only showed a marginal effect on EGF-dependent mitogenic activity. Thus, Gab1 plays a pivotal role in the EGFR signaling pathway via the formation of the EGFR-Gab1-SHP-2 complex, and alteration in the expression and function of Gab1 is implicated in the neoplastic progression of SHE cells.
已知衔接蛋白Grb2相关结合蛋白-1（Gab1）在表皮生长因子（EGF）受体受刺激时会与SHP-2酪氨酸磷酸酶结合。为阐明这两种蛋白在EGF受体（EGFR）信号传导中的作用，并确定它们在肿瘤细胞进展过程中可能发生的改变，我们在叙利亚仓鼠胚胎（SHE）细胞系肿瘤进展模型中研究了这些蛋白。具体而言，我们使用了石棉转化的SHE成纤维细胞：10W + 8克隆，它是永生化但无致瘤性的；以及10W2T克隆，它具有致瘤性。在10W + 8细胞中检测到了Gab1，并观察到了EGFR-Gab1-SHP-2复合物的EGF依赖性形成。克隆仓鼠Gab1 cDNA后，Gab1的外源性表达显著增强了10W + 8细胞中EGF依赖性的促有丝分裂活性。另一方面，在10W2T细胞中未检测到Gab1，并且SHP-2与EGFR的EGF依赖性结合也不存在。转染的10W2T细胞中外源性Gab1的表达恢复了SHP-2与EGFR的EGF依赖性结合，尽管它对EGF依赖性促有丝分裂活性仅显示出微弱的影响。因此，Gab1通过形成EGFR-Gab1-SHP-2复合物在EGFR信号通路中起关键作用，并且Gab1表达和功能的改变与SHE细胞的肿瘤进展有关。
