Fig. 12.

Pretreatment with insulin attenuates the binding of PTP1B and PDGFR-β. Cells were treated for 48 h without or with 100 nM insulin, followed by treatment for 24 h with control adenovirus expressing EGFP or adenovirus expressing catalytically inactive mutant PTP1B (C215S-PTP1B), in the continued absence or presence of insulin. Cells were then subjected to lysis and lysates were immunoprecipitated using nonspecific IgG as control (nonspecific IP) or anti-PTP1B (specific IP). Coimmunoprecipitated PDGFR-β levels were measured by Western blot analysis. A: results from a representative Western blot. B: means ± SE from 3 experiments, normalized to control values (specific IP, control virus). *P < 0.05, compared with values from cells treated with mutant virus plus insulin followed by specific IP by Student's t-test.