FIG. 5.

Effect of cell attachment on PIG-induced tyrosine phosphorylation of pp125^FAK, paxillin and IRS-1, and pp125^FAK and IRS-1 association. Serum-starved adherent 3T3-L1 adipocytes were detached, held in suspension (30 min), and then stimulated (10 min) in the absence or presence of increasing concentrations of PIG 41, replated on fibronectin-coated culture dishes in the absence or presence of 0.5 mM GRGDSP or GRADSP peptide, and further incubated (20 min). pp125^FAK, paxillin, and IRS-1 were immunoprecipitated (IP) with corresponding antibodies from defatted cell lysates and then immunoblotted (IB) with antiphosphotyrosine or anti-IRS-1 antibodies (pp125^FAK only). Phosphorimages of three to four independent experiments were quantitatively evaluated as fold stimulation (mean ± standard deviation). Basal tyrosine phosphorylation and association are set at 1 in each case.