FIG. 5.

M33-induced CREB activation is defective in PKC-depleted cells. (A) HEK293 cells were treated overnight with the phorbol ester PMA to deplete endogenous PKCs. HEK293 cells express several isoforms of PKC including PKC-α, PKC-β1, PKC-β2, and PKC-ɛ and Western blotting of cells treated with 0.2 or 1.0 μM PMA confirmed that these conditions resulted in >90% depletion of endogenous PKCs. (B) After depletion of endogenous PKCs, untreated or treated cells were transiently transfected with empty vector (mock) or M33FLAG(WT) (250 ng) and CREB-driven luciferase activity was measured and normalized to Renilla luciferase. The data represent the mean ± the SE of four independent experiments performed in duplicate. **, P ≤ 0.005.