Figure 3

p38β is critical to LCM-induced phosphorylation of C/EBPβ at Thr-188 and upregulation of atrogin1/MAFbx. C2C12 myoblasts were transfected with siRNA as indicated. After differentiation, myotubes were treated with LCM or control medium. In 1 h, levels of p38α and p38β, and phosphorylation of C/EBPβ at Thr-188 were evaluated by western blotting (A). In 8 h, levels of atrogin1/MAFbx were evaluated by western blotting (B). Optical density of the bands that represent C/EBP phosphorylated at Thr-188 or atrogin1/MAFbx was analyzed by ANOVA. *denotes a difference from control without LCM treatment and †denotes a difference from control with LCM treatment (P <0.05). LCM, Lewis lung carcinoma cell-conditioned medium.