FIG. 2.

Activation of p38 stimulates gene transcription in myocytes. (A) Myocytes were cotransfected with a 5×GAL4-Luc reporter plasmid (1 μg/plate) and expression vectors encoding p38, MKK6b, and/or MKK6b(EE) (300 ng each) and/or GAL4-Elk or GAL4-Elk(Ala383/389) (10 ng each) in the presence (+) or absence of the specific p38 inhibitor SB202190 (20 μM) as indicated. After 48 h, cells were harvested, and luciferase activity was determined and normalized to the protein content of each extract. Luciferase activity expressed by cells transfected with pSRα was given an arbitrary value of 1. The results are presented as means ± standard errors (error bars) and represent six individual experiments. (B) Myocytes were transfected with expression vectors encoding MKK6b, M2-Flag-tagged p38, or empty vector (3 μg each) as indicated. M2-p38 was immunoprecipitated with anti-M2 antibody (Kodak Inc.), and its activity was measured as described in the legend to Fig. 1A.