Figure 4.

R49 and R149 residues play a crucial role in the activation of p38α. The Flag-p38α wild type or R49/149K mutant were expressed in p38α-knockdown cells. Cells were stimulated with AraC (1 μM) and the activation of p38α was examined directly by Western Blotting using specific anti-phospho-p38 antibodies (A) or after immunoprecipitation (B). Phosphorylation was greatly reduced in R49/149K. Alternatively, the cells were treated with sorbitol (150 mM) and the activation of p38α was examined by Western Blotting (C). The overexpression of PRMT1 (R2-1) enhanced the activation of p38α upon sorbitol stimulation (D). The levels of pp38 and p38 were quantified by Multi-Gauge V3.0 analysis. All results shown are representatives of three independent experiments. Statistical analysis was performed with results from three separate experiments. *** p < 0.005 and ** p < 0.01 as compared with WT.