The vascular endothelial growth factor receptor KDR activates multiple signal transduction pathways in porcine aortic endothelial cells
The vascular endothelial growth factor receptor KDR activates multiple signal transduction pathways in porcine aortic endothelial cells
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DOI：
10.1074/jbc.272.51.32521
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发表时间：
1997-12-19
影响因子：
4.8
通讯作者：
Waltenberger, J
中科院分区：
文献类型：
--
作者：
Kroll, J;Waltenberger, J
血管内皮生长因子A（在此称为VEGF）是内皮特异性生长因子，其结合两种不同的受体酪氨酸激酶，命名为Flt-1和KDR/Flk-1。VEGF刺激两种受体的自磷酸化，但对它们的信号转导特性知之甚少。在这项研究中，我们使用过表达KDR的猪主动脉内皮细胞（PAE）（PAE/KDR）来评估KDR与细胞内蛋白的相互作用，并将其与表达Flt-1的PAE细胞（PAE/Flt-1）进行比较。VEGF诱导的KDR刺激导致Shc的46、52-和66-kDa同种型的缔合和磷酸化，并诱导Shc-Grb 2复合物形成。以类似的方式，KDR与Grb 2和Nck以配体依赖的方式相关联，表明Shc、Grb 2和Nck是参与内皮功能调节的潜在候选者。另一个强有力的候选者是促分裂原活化蛋白（MAP）激酶，其响应于VEGF刺激而被强烈活化，如通过特异性底物髓鞘碱性蛋白的磷酸化所证明的。特异性MAP激酶抑制剂PD 98059抑制MAP激酶活化，可抑制VEGF诱导的PAE/KDR细胞增殖。相反，VEGF诱导的Flt-1的刺激不激活PAE/Flt-1细胞中的MAP激酶。在这项研究中，我们提供了前两个分子的例子，即SHP-1和SHP-2，可能在功能上能够抵消内皮细胞对VEGF的反应。这两种SH 2蛋白酪氨酸磷酸酶与继发于VEGF刺激的KDR物理相关，这两种分子参与VEGF诱导信号的产生和/或调节的可能性令人感兴趣。总之，我们的研究结果大大拓宽了HDR相关分子的谱，表明内皮功能和血管生成是由不同的信号转导级联网络调节的。
Vascular endothelial growth factor A (here referred to as VEGF) is an endothelium-specific growth factor that binds to two distinct receptor tyrosine kinases, designated Flt-1 and KDR/Flk-1. VEGF stimulates autophosphorylation of both receptors, but little is known about their signal transduction properties. In this study, we used porcine aortic endothelial (PAE) cells overexpressing KDR (PAE/KDR) to evaluate the interaction of KDR with intracellular proteins and compared them with Flt-1-expressing PAE cells (PAE/Flt-1). VEGF-induced stimulation of KDR results in the association and phosphorylation of the 46, 52-, and 66-kDa isoforms of Shc and the induction of Shc-Grb2 complex formation. In a similar fashion, KDR associates with Grb2 and Nck in a ligand-dependent fashion, suggesting Shc, Grb2, and Nck as potential candidates involved in the regulation of endothelial function. Another strong candidate is mitogen-activated protein (MAP) kinase, which is strongly activated in response to VEGF stimulation as demonstrated by phosphorylation of the specific substrate myelin basic protein. Inhibition of MAP kinase activation by PD98059, a specific MAP kinase kinase inhibitor, results in inhibition of VEGF-induced proliferation of PAE/KDR cells. In contrast, VEGF-induced stimulation of Flt-1 does not activate MAP kinase in PAE/Flt-1 cells, In this study we provide the first two examples of molecules potentially capable of functionally counteracting the endothelial response to VEGF, namely SHP-1 and SHP-2. These two SH2 protein-tyrosine phosphatases physically associate with KDR secondary to VEGF stimulation, raising the interesting possibility that both molecules participate in the generation and/or modulation of VEGF-induced signals. Taken together, our results substantially broaden the spectrum of HDR-associating molecules, indicating that endothelial function and angiogenesis are regulated by a diverse network of signal transduction cascades.