Qi J H, Ito N, Claesson-Welsh L
Department of Medical Biochemistry and Microbiology, Uppsala University, Biomedical Center, Box 575, S-751 23 Uppsala, Sweden.
J Biol Chem. 1999 May 14;274(20):14455-63. doi: 10.1074/jbc.274.20.14455.
SHP-2 is a ubiquitously expressed Src homology-2-containing cytosolic tyrosine phosphatase that binds to and becomes tyrosine-phosphorylated by the activated platelet-derived growth factor receptor-beta (PDGFR-beta). Removal of the binding site on the receptor, by mutation of Tyr1009 to Phe1009 (denoted Y1009F), led to loss of PDGF-stimulated phosphatase activity in cells expressing the mutated receptor, and these cells failed to form membrane edge ruffles and to migrate toward PDGF. Furthermore, treatment with phosphatase inhibitors phenylarsine oxide (PAO) and orthovanadate led to loss of PDGF-stimulated phosphatase activity and attenuated PDGF-stimulated migration of wild type PDGFR-beta cells. Treatment of wild type PDGFR-beta cells with combinations of PAO or orthovanadate and phosphatidylinositol 3-kinase inhibitors wortmannin or LY294002 resulted in a synergistic inhibition of PDGFR-beta-mediated cell migration. PDGF stimulation of wild type PDGFR-beta cells led to induction of p125 focal adhesion kinase (FAK) activity at low concentrations of the growth factor and a decrease at higher concentrations. In the mutant Y1009F cells and in wild type PDGFR-beta cells treated with PAO and orthovanadate, FAK activity was not increased in response to PDGF. These results suggest that SHP-2 activity is involved in regulation of FAK activity and thereby of cell migration through PDGFR-beta, independently of phosphatidylinositol 3-kinase.
SHP-2是一种广泛表达的含Src同源2结构域的胞质酪氨酸磷酸酶，它与活化的血小板衍生生长因子受体β（PDGFR-β）结合并被其酪氨酸磷酸化。通过将Tyr1009突变为Phe1009（记为Y1009F）去除受体上的结合位点，导致表达突变受体的细胞中PDGF刺激的磷酸酶活性丧失，并且这些细胞无法形成膜边缘褶皱以及向PDGF迁移。此外，用磷酸酶抑制剂氧化苯胂（PAO）和原钒酸盐处理导致PDGF刺激的磷酸酶活性丧失，并减弱了野生型PDGFR-β细胞的PDGF刺激的迁移。用PAO或原钒酸盐与磷脂酰肌醇3-激酶抑制剂渥曼青霉素或LY294002的组合处理野生型PDGFR-β细胞，导致对PDGFR-β介导的细胞迁移的协同抑制。低浓度生长因子时，野生型PDGFR-β细胞的PDGF刺激导致p125粘着斑激酶（FAK）活性诱导，而高浓度时则降低。在突变的Y1009F细胞以及用PAO和原钒酸盐处理的野生型PDGFR-β细胞中，FAK活性不会因PDGF而增加。这些结果表明，SHP-2活性参与FAK活性的调节，从而通过PDGFR-β参与细胞迁移的调节，且不依赖于磷脂酰肌醇3-激酶。
