Figure 4. GSK3β-mediated phosphorylation of USF2 affects activation of target gene promoters.

(A–C) HeLa cells were cotransfected with the indicated luciferase gene construct and with WT or mutant p3xFLAG-USF2-myc-CMV24 or the appropriate empty vector. The measured luciferase activity is plotted as fold induction compared to the luciferase activity measured in the control transfected with the empty expression vector. *, significant difference WT vs. mutant. (D) Representative Western blot of the transfected constructs. 50 µg of protein from transfected cells were probed with an antibody against myc-tag and α-tubulin.