FIG. 4.
Activation of p38 MAPK by various stress stimuli. HEK293 cells expressing empty vector or wt or dominant-negative alpha-4 protein were subjected to different stress stimuli (IL-1β, anisomycin, or sorbitol). Dose-response curves depict activation of p38 MAPK as measured by the ratio of immunoblotting for anti-phospho-(Thr180/Tyr182) p38 MAPK versus anti-p38 MAPK protein. (A) Cells treated with 0 to 5 ng/ml IL-1β for 20 min. (B) Cells treated with 0 to 10 ng/ml anisomycin for 20 min. (C) Cells treated with 0 to 0.4 M sorbitol for 20 min. Cells with FLAG-alpha-4 DND are represented by solid circles, cells with FLAG-alpha-4 wt by solid squares, and cells with empty vector by open diamonds.