Figure 1.

Expression profiles of p38 isoforms in mature muscles and C2C12 cells. (A) Detection of different p38 isoforms in selected mouse tissues by semiquantitative RT-PCR analysis. GAPDH was used as a loading control. (B) 293T cells were separately transfected with plasmids encoding Flag-tagged p38α, β, γ, and δ. Different Flag-p38 isoforms were immunoprecipitated (IP) from cell extracts with the anti-Flag antibody, and the immunoprecipitates were subjected to SDS-polyacrylamide gel electrophoresis (PAGE) and examined by Western blotting (WB) by using isoform-specific p38 antibodies. (C) C2C12 cells were let to grow and differentiate in cell culture. Cells were harvested at different time points as indicated, and WCEs were subjected to SDS-PAGE followed by Western blotting analysis.