Fig. 6. PDGF-r kinase activity during PTPs inhibition. (A,B) 1x10⁶ NIH3T3 cells were serum starved for 24 hours and then stimulated with 30 ng/ml PDGF-BB and with the growth factor together with 0.1 mM pervanadate. PDGF-r was immunoprecipitated from lysates, and an immunokinase assay was performed as reported in the Materials and Methods. PDGF-r autophosphorylation kinase activity is reported in A and PDGF-r kinase activity towards GST-PLC1 is reported in B. The ratio between the densitometric analyses of kinase assays and normalization blots (anti PDGF-r or anti-PLC1 immunoblots) is shown in both A and B. (C) 1x10⁶ NIH3T3 cells were serum starved for 24 hours and then stimulated with 30 ng/ml PDGF-BB and with the growth factor together with 0.1 mM pervanadate. PDGF-r was immunoprecipitated from lysates and an anti-phospho-Tyr857 immunoblot was performed. Equalisation was checked by stripping the blot and reprobing with anti-PDGF-r antibodies. The results are the means of at least three experiments.