Fig. 8.

Pretreatment with insulin suppresses the antimotogenic effect of ectopic PTP1B. Cells were treated for 24 h without or with 100 nM insulin and with control virus expressing enhanced green fluorescent protein (EGFP) or with virus expressing PTP1B at multiplicity of infection values of 10–15. Cells were then rinsed to remove residual virus and further incubated for 48 h to allow time for PTP1B expression in the continued absence or presence of insulin. Cells were treated without or with 2 ng/ml PDGF-BB during the last 24 h of incubation. A: PTP1B levels as determined by Western blot analysis. The doublet of bands for PTP1B represents endogenous and ectopic PTP1B, the latter of which has a slightly greater mass than the endogenous protein, due to the addition of a hemagglutinin tag. B: effect of insulin on the capacity of ectopic PTP1B to suppress PDGF-induced cell motility. Results are means ± SE of 3 experiments. *P < 0.05, compared with “EGFP + PDGF” treatment category by ANOVA, followed by Fisher's PLSD.