Fig. 1. p21 induction by FGF-2, PDGF, and TGF-ß1. NIH 3T3 cells were starved in 0.2% NBCS for 4 h, after which increasing amounts of FGF-2 (A), PDGF (B), or TGF-ß1 (C) were added, and the cells were incubated for 12 h further. Cell lysates were prepared and analyzed by 12.5% SDS-PAGE, followed by immunoblotting with anti-p21, anti-p27Kip1, anti-phospho-ERK1/2, and anti-ERK2 antibodies, as indicated. The protein levels were quantitated, and p27Kip1 and ERK2 levels were used as a loading controls for p21 and phospho-ERK1/2, respectively. Fold inductions of p21 as compared with nontreated cells starved for 16 h are shown.