Tyrosine phosphatase SHP-2 is involved in regulation of platelet-derived growth factor-induced migration

SHP-2 is a ubiquitously expressed Src homology-2-containing cytosolic tyros ine phosphatase that binds to and becomes tyrosine-phosphorylated by the ac tivated platelet-derived growth factor receptor-beta (PDGFR-beta). Removal of the binding site on the receptor, by mutation of Tyr(1009) to Phe(1009) (denoted Y1009F), led to loss of PDGF-stimulated phosphatase activity in ce lls expressing the mutated receptor, and these cells failed to form membran e edge ruffles and to migrate toward PDGF. Furthermore, treatment with phos phatase inhibitors phenylarsine oxide (PAO) and orthovanadate led to loss o f PDGF-stimulated phosphatase activity and attenuated PDGF-stimulated migra tion of wild type PDGFR-beta cells. Treatment of wild type PDGFR-beta cells with combinations of PAO or orthovanadate and phosphatidylinositol 3-kinas e inhibitors wortmannin or LY294002 resulted in a synergistic inhibition of PDGFR-beta-mediated cell migration. PDGF stimulation of wild type PDGFR-be ta cells led to induction of p125 focal adhesion kinase (FAK) activity at l ow concentrations of the growth factor and a decrease at higher concentrati ons. In the mutant Y1009F cells and in wild type PDGFR-beta cells treated w ith PAO and orthovanadate, FAK activity was not increased in response to PD GF. These results suggest that SHP-2 activity is involved in regulation of FAK activity and thereby of cell migration through PDGFR-beta, independentl y of phosphatidylinositol 3-kinase.