FIG. 5.

Inhibition of PHIP1 expression blocks IGF-1- and IRS2-induced mitogenesis. INS-1 cells were transiently transfected with nonsilencing scrambled (SCR) and anti-PHIP1 (SiPHIP1) siRNAs and infected with AdGFP or AdIRS2 at an MOI of 200. (A) [³H]thymidine incorporation was measured 24 h after IGF-1 stimulation as indicated in Materials and Methods. Experiments were performed three times in triplicate. Results are shown as means ± SD. *, P < 0.05 versus results for cells transfected with SCR siRNA, infected with AdGFP (SCR + AdGFP), and stimulated with IGF-1 (+IGF); #, P < 0.05 versus results for cells transfected with SCR, transfected with AdIRS2 (SCR + AdIRS2), and not stimulated with IGF-1 (−IGF); **, P < 0.05 versus results for cells transfected with SCR siRNA, infected with AdIRS2, and stimulated with IGF-1. (B) Immunoblot analyses for PHIP1, IRS2, phospho-Ser⁴⁷³ PKB, cyclin D2, and actin in cells treated as described for panel A. The immunoblots are representative of at least two independent experiments. +, present; −, absent.