Scaffolding protein Gab2 mediates fibroblast transformation by the SEA tyrosine kinase
Scaffolding protein Gab2 mediates fibroblast transformation by the SEA tyrosine kinase
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DOI：
10.1038/sj.onc.1206742
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发表时间：
2003-09-25
期刊：
影响因子：
8
通讯作者：
Hayman, MJ
中科院分区：
文献类型：
--
作者：
Ischenko, I;Petrenko, O;Hayman, MJ
V-SEA 对成纤维细胞的转化涉及 ERK 和磷脂酰肌醇 3 激酶 (PI3K) 途径的激活。效应蛋白是 ERK 和 PI3K 通路的关键介质，即 Grb2、酪氨酸磷酸酶、SHP2 和 PI3K，与 V-SEA 羧基末端区域双齿基序中发现的两个磷酸酪氨酸相互作用。遗传分析表明，虽然 Y557 是 PI3K-Akt 途径的主要结合位点，因此是 PI3K-Akt 途径的激活剂，但 Y564 也有助于该途径的激活。 Y564 位于 Grb2 结合基序内，这提出了与 Grb2 相关的蛋白质可能对这种 PI3K 激活很重要的可能性。支架蛋白 Gab1 和/或 Gab2 是发挥这一作用的候选蛋白。在本报告中，我们证明 V-SEA 优先与 Gab2 相互作用。此外，通过使用 Gab2 缺失的成纤维细胞，我们证明 Gab2 对于 V-SEA 成纤维细胞转化至关重要。使用 Gab2 的突变形式，我们表明 V-SEA 诱导的转化需要通过 Gab2 激活 PI3K-Akt 途径。然而，有效的成纤维细胞转化还需要 Gab2 上的 SHP2 相互作用位点。
Transformation of fibroblasts by V-SEA involves activation of the ERK and phosphatidylinositol 3-kinase (PI3K) pathways. Effector proteins that are key mediators of the ERK and PI3K pathways, namely Grb2, the tyrosine phosphatase, SHP2 and PI3K, interact with the two phosphotyrosines found in the bidentate motif in the carboxy-terminal region of V-SEA. Genetic analysis demonstrated that while Y557 was a primary binding site and thus activator of the PI3K-Akt pathway, Y564 also contributed to the activation of this pathway. Y564 was located within a Grb2-binding motif, this raised the possibility that a protein that associated with Grb2 might be important for this PI3K activation. The scaffolding proteins Gab1 and/or Gab2 were candidates for this role. In this report, we demonstrate that V-SEA preferentially interacts with Gab2. Furthermore by using Gab2 null fibroblasts, we demonstrate that Gab2 is essential for fibroblast transformation by V-SEA. Using mutant forms of Gab2, we show that activation of the PI3K-Akt pathway via Gab2 is required for V-SEA-induced transformation. However, efficient fibroblast transformation also requires the SHP2 interaction site on Gab2.