REEXAMINING INTERACTION OF THE SH2 DOMAINS OF SYP AND GAP WITH INSULIN AND IGF-1 RECEPTORS IN THE 2-HYBRID SYSTEM

Direct interaction of effector proteins such as the p85 regulatory sub unit of phosphatidylinositol 3-kinase (PI 3-kinase), SYP (SH2-domain-c ontaining tyrosine phosphatase) and GAP (Ras-GTPase activating protein ) with the insulin receptor (IR) and insulin-like growth factor-1 (IGF -1) type 1 receptor (IGF-IR) has beer, reported in some studies. Inter action of SYP and GAP with IR and IGF-1R was re-investigated here in t he two-hybrid system by assessing his3/lacZ activation in S. cerevisia e. The experiments were performed with the cytoplasmic beta domain of IR and IGF-1R and various SH2-subdomains of SYP and GAP. None of the s ubdomains of SYP and GAP tested were able to activate his3/lacZ, where as these reporter genes were strongly activated when p85 was used as w e have recently shown. Thus, interaction of SYP and GAP with IR and IG F-1R, if any, would be weak and/or transient as compared to that of p8 5.