TYR-716 IN THE PLATELET-DERIVED GROWTH-FACTOR BETA-RECEPTOR KINASE INSERT IS INVOLVED IN GRB2 BINDING AND RAS ACTIVATION
TYR-716 IN THE PLATELET-DERIVED GROWTH-FACTOR BETA-RECEPTOR KINASE INSERT IS INVOLVED IN GRB2 BINDING AND RAS ACTIVATION
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DOI：
10.1128/mcb.14.10.6715
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发表时间：
1994-10-01
影响因子：
5.3
通讯作者：
CLAESSONWELSH, L
中科院分区：
文献类型：
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作者：
ARVIDSSON, AK;RUPP, E;CLAESSONWELSH, L
配体对血小板衍生生长因子(PDGF)β受体的刺激导致其固有酪氨酸激酶的激活和受体细胞内部分的自动磷酸化。自磷酸化的酪氨酸残基介导与下游信号转导分子的相互作用，从而启动不同的信号转导途径。导致GTP结合蛋白RAS激活的途径涉及适配分子Grb2。在这里，我们展示了在PDGFβ受体激酶插入中的一个新的自磷酸化位点Tyr-716，在体外和体内介导了Grb2的直接结合。在一组突变的PDGFβ受体中，Tyr-716和先前已知的自动磷酸化位点分别发生突变，只有PDGFR beta Y716F未能与Grb2结合。此外，含有Tyr-716的人工合成的磷酸化多肽与Grb2结合，并特异性地阻断Grb2与野生型受体之间的相互作用。此外，Y716(P)多肽还能显著降低PDGF对通透性成纤维细胞和表达PDGFβ受体的猪主动脉内皮细胞RAS结合的GTP含量。突变的PDGFRβY716F仍然介导着丝裂原激活的蛋白激酶的激活和对PDGF的响应增加的DNA合成，表明多个信号转导途径从激活的PDGFβ受体转导有丝分裂信号。
Ligand stimulation of the platelet-derived growth factor (PDGF) beta-receptor leads to activation of its intrinsic tyrosine kinase and autophosphorylation of the intracellular part of the receptor. The autophosphorylated tyrosine residues mediate interactions with downstream signal transduction molecules and thereby initiate different signalling pathways. A pathway leading to activation of the GTP-binding protein Ras involves the adaptor molecule GRB2. Here we show that Tyr-716, a novel autophosphorylation site in the PDGF beta-receptor kinase insert, mediates direct binding of GRB2 in vitro and in vivo. In a panel of mutant PDGF beta-receptors, in which Tyr-716 and the previously known autophosphorylation sites were individually mutated, only PDGFR beta Y716F failed to bind GRB2. Furthermore, a synthetic phosphorylated peptide containing Tyr-716 bound GRB2, and this peptide specifically interrupted the interaction between GRB2 and the wild-type receptor. In addition, the Y716(P) peptide significantly decreased the amount of GTP bound to Ras in response to PDGF in permeabilized fibroblasts as well as in porcine aortic endothelial cells expressing transfected PDGF beta-receptors. The mutant PDGFR beta Y716F still mediated activation of mitogen-activated protein kinases and an increased DNA synthesis in response to PDGF, indicating that multiple signal transduction pathways transduce mitogenic signals from the activated PDGF beta-receptor.