The scaffolding adapter Gab1 mediates vascular endothelial growth factor signaling and is required for endothelial cell migration and capillary formation
The scaffolding adapter Gab1 mediates vascular endothelial growth factor signaling and is required for endothelial cell migration and capillary formation
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DOI：
10.1074/jbc.m611327200
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发表时间：
2007-03-16
影响因子：
4.8
通讯作者：
Royal, Isabelle
中科院分区：
文献类型：
--
作者：
Laramee, Melanie;Chabot, Catherine;Royal, Isabelle
血管内皮生长因子（VEGF）参与促进内皮细胞增殖、迁移和毛细血管形成。这些活性主要由VEGFR2受体酪氨酸激酶介导，该激酶受到刺激后，可促进多种蛋白质的激活，包括磷脂酶C γ (PLC γ)、磷脂酰肌醇3-激酶（PI3K）、Akt、Src和ERK1/2。然而，导致这些靶标激活的vegfr2近端信号事件仍然不明确。我们已经确定Gab1适配器是vegf刺激细胞中一种新的酪氨酸磷酸化蛋白。在牛主动脉内皮细胞中，Gab1与VEGFR2、Grb2、PI3K、SHP2、Shc和PLC γ相关，其过表达增强了vegf依赖性细胞的迁移。重要的是，使用小干扰rna沉默Gab1会导致PLC γ、ERK1/2、Src和Akt的激活受损；阻断vegf诱导的内皮细胞迁移；扰乱肌动蛋白重组和毛细血管形成。此外，在人胚胎肾293细胞和牛主动脉内皮细胞中，VEGFR2与不能结合SHP2或PI3K的Gab1突变体的共表达类似于在Gab1缺失细胞中观察到的缺陷。因此，我们的工作确定了Gabl是内皮细胞迁移和毛细血管形成的一个新的关键调控成分，并揭示了它在血管生成所需的vegf诱发信号通路激活中的关键作用。
Vascular endothelial growth factor (VEGF) is involved in the promotion of endothelial cell proliferation, migration, and capillary formation. These activities are mainly mediated by the VEGFR2 receptor tyrosine kinase that upon stimulation, promotes the activation of numerous proteins including phospholipase C gamma (PLC gamma), phosphatidylinositol 3-kinase (PI3K), Akt, Src, and ERK1/2. However, the VEGFR2-proximal signaling events leading to the activation of these targets remain ill defined. We have identified the Gab1 adapter as a novel tyrosine-phosphorylated protein in VEGF-stimulated cells. In bovine aortic endothelial cells, Gab1 associates with VEGFR2, Grb2, PI3K, SHP2, Shc, and PLC gamma, and its overexpression enhances VEGF-dependent cell migration. Importantly, silencing of Gab1 using small interfering RNAs leads to the impaired activation of PLC gamma, ERK1/2, Src, and Akt; blocks VEGF-induced endothelial cell migration; and perturbs actin reorganization and capillary formation. In addition, co-expression of VEGFR2 with Gab1 mutants unable to bind SHP2 or PI3K in human embryonic kidney 293 cells and bovine aortic endothelial cells mimics the defects observed in Gab1-depleted cells. Our work thus identifies Gabl as a novel critical regulatory component of endothelial cell migration and capillary formation and reveals its key role in the activation of VEGF-evoked signaling pathways required for angiogenesis.