FIG 4.

p38 autophosphorylation in GRA-stimulated cells. (A) RAW 264.7 cells were transiently transfected with either WT or DN MKK3/6 expression plasmids (24 h) and treated with SB203580 (30 μM) for 1 h before infection and stimulation with GRA (4 h). The levels of total and phosphorylated p38 were determined by Western blotting. (B) Cells were treated as described for panel A. Cell lysates were then subjected to immunoprecipitation by anti-p-p38 antibody and Western blotting using anti-TAB1 antibody. (C) Cells were treated as stated for panel A. Cell lysates were then subjected to immunoprecipitation by anti-TAB1 antibody and Western blotting using anti-p-p38 antibody. The bands were analyzed densitometrically, and the fold changes are indicated below each blot. All experiments were repeated at least three times each, and one set of representative data is shown. IP, immunoprecipitation using the indicated antibody (Ab); IB, immunoblot analysis using the indicated Ab.