Chemical dissection of the effects of tyrosine phosphorylation of SHP-2.

摘要: The regulation of the protein tyrosine phosphatase (PTPase) SHP-2 by phosphorylation has been difficult to elucidate because intrinsic instability phosphoprotein. In past, expressed ligation used site-specifically incorporate phosphotyrosine mimic Pmp (phosphonomethylene phenylalanine) into two sites (542, 580) one at a time analyze effects on catalytic behavior. this study, we have incorporated Pmps simultaneously and examined double phosphorylation. We found that groups show close additive PTPase stimulation, suggesting dual SH2 domain occupancy. relative analogue difluoromethylene phosphonophenylalanine (F 2 Pmp) compared those were also examined. It was F showed slightly enhanced stimulation with analogue, consistent its higher affinity for domains. Taken together bis-Pmp studies, these data suggest C-terminus could give rise 9-fold overall activation, 30-50% value associated deletion Catalytically inactive forms phosphorylated proteins produced ligation. This allowed systematic analysis intermolecular autodephosphorylation SHP-2, which revealed how conformational plasticity can modulate stability.