Figure 3

Effect of constitutively active 4EBP-1 on turnover of p27Kip1 and cyclin D1. MCF7-4EBP-1-5A cells were cultured in the presence (open circles) or absence (closed circles) of pon A for 24 hours at which time cycloheximide (100 μg/ml) was added. At the indicated time cells were harvested for analysis of p27Kip1 (left) or cyclin D1 (right) protein levels by Western blotting. Protein levels were then estimated by densitometry.