FIG. 1.

ERK5 stimulation of the MEF2-dependent reporter construct in three different cells lines. DO11.10 (A), NIH 3T3 (C), and S194 (D) cells were transfected with a MEF2-luc (35) and full-length wild-type, full-length kinase-deficient [ERK5(AEF), ERK5 D183A, and ERK5 D203A], or truncated ERK5. Activated MEK5 [MEK5(D)] was added where indicated. (D) Mutant MEF2-luc (35) was used to confirm MEF2 specificity. Open bars indicate activity in unstimulated cells. Hatched or filled bars indicate activity in cells stimulated with PMA and ionomycin. Expression of transfected ERK5 constructs in DO11.10 and NIH 3T3 cells was determined by Western blot analysis using anti-ERK5 (B) or anti-HA (C) antibodies.