Fig. 8. PDGF-r and PDGF-r phosphorylation persist for many hours. 1x10⁶ NIH3T3 cells were serum starved for 24 hours then stimulated with 30 ng/ml PDGF-BB for the indicated times. PDGF-r was immunoprecipitated from lysates and an antiphosphotyrosine immunoblot was performed (A). The blot was stripped and reprobed with anti-PDGF-r antibodies (B).