Fig. 6. Periplakin expression modulates PKB-dependent FOXO4 regulation. (A) 293T cells were transfected with a TK-renilla-luciferase (internal control) and 6xDBE luciferase reporter construct (Medema et al., 2000), in the absence or presence of FOXO4. Different amounts (µg) of full-length periplakin, myc-c-ppl or HA-PKB were cotransfected with FOXO4. 36 hours after transfection lysates were prepared and luciferase counts were measured and normalized against renilla luciferase counts. 6xDBE activity in the absence of FOXO4 was set at 1. Results represent the averages of three independent experiments. (B) Periplakin expression reduces PKB-dependent FOXO4 phosphorylation. 293T cells were transfected with the 0.5 µg full-length periplakin or 1.0 µg c-ppl and 1 µg HA-FOXO4. HA-FOXO4 was immunoprecipitated and the level of PKB-dependent phosphorylation was determined by immunoblotting using a phospho-specific antibody against pSer193.