FIGURE 3.

p38 is activated through a β-arrestin 2-dependent mechanism in TLR4 signaling. A, WT, β-arrestin 2 KO, and β-arrestin 1 KO MEFs were stimulated with LPS (20 μg/ml) for the indicated times. Levels of phospho-p38, phospho-JNK and phospho-ERK were examined by immunoblotting with specific antibodies. B, β-arrestin 1/2 DKO MEFs were transfected with β-arrestin 2 full-length construct or control vector, and analyzed for the expression of phospho-p38 by Western blot following stimulation with LPS (20 μg/ml) for 15 min. Results are representatives of three independent experiments.