FIG. 4.

Forkhead-induced cell cycle exit is mediated by PI3K signaling. (A) MCF7 cells were serum starved for 48 or 72 h and subsequently treated with insulin for 24 or 48 h, with or without a 30-min preincubation with LY294002. p130 protein levels were then analyzed by Western blotting. pp130, hyperphosphorylated p130. (B) U87MG cells were treated with 10 μM LY294002 (LY) for 0, 10, or 24 h. Total cellular lysates were immunoblotted for the presence of p130 protein and T32-phosphorylated FKHR-L1. (C) p130 protein levels of asynchronous (asynch) DLD-1 cells were compared to those of DLD-1 cells that were either serum starved (− FCS) for 48 or 72 h or treated with LY294002 for 16 h.