SHP2 ASSOCIATES DIRECTLY WITH TYROSINE-PHOSPHORYLATED P90 (SNT) PROTEIN IN FGF-STIMULATED CELLS

In a number of cell lines responsive to basic fibroblast growth factor (bFGF), two major tyrosine phosphorylated proteins, of molecular weig hts around 120kDa and 90kDa, are precipitated. along with the tyrosine phosphatase SHP2 from the lysates of stimulated cells, The docker pro tein Gab-1 represents at least part of the 120kDa protein(s). The p90 protein was identified as the SNT protein, The two SH2 domains of SHP2 bind directly and synergistically to tyrosine phosphorylated SNT. Tyr osine phosphorylated SNT does not bind SHP1 and does riot appear to be an in vivo substrate of SHP2 but is likely to function as an adapter protein in FGF-signalling. (C) 1997 Academic Press.