Suppression of FoxO1 by insulin-induced C/EBPβ isoforms. A: Cos7 cells were cultured for 24 h in serum-free DMEM in the absence or presence of insulin as indicated. Cellular extracts
were subjected to SDS-PAGE followed by Western blotting as described in research design and methods using anti-LAP, -CHOP, and -tubulin antibodies as indicated. Representative blots are shown. B: Cos7 cells were transfected as described in research design and methods with FoxO1 reporter plasmid (FRE3-TK-Luciferase) and cotransfected with empty (–), FoxO1(TSS), or FoxO1(AAA) expression plasmids
in the presence of vehicle (black bars) or insulin (hatched bars) as indicated. Luciferase activity of empty-transfected cells
normalized to β-galactosidase was defined as 1.0. Mean ± SE for five independent experiments. *Significant as compared with
respective vehicle-treated cells (P < 0.05).