Figure 5
(A) Effect of PIF concentration on the chymotrypsin-like enzyme activity of the proteasome in C2C12 myotubes in the absence (×) or presence (▪) of 10 μ M PD98059. The experiment was repeated three times (n=9). Differences from the control are indicated as a, P<0.001, while differences from those in the absence of inhibitor are indicated as b, P<0.001. (B–D) Western blots of soluble extracts of C2C12 myotubes treated with 0 (lanes 1 and 7); 1.0 (lanes 2 and 8); 2.1 (lanes 3 and 9); 4.2 (lanes 4 and 10); 10 (lanes 5 and 11) or 20 nM PIF (lanes 6 and 12) without pretreatment (lanes 1–6) and after pretreatment for 2 h in the presence of 10 μ M PD98059 (lanes 7–12). Bands were detected using antibody to 20S proteasome α-subunits (B), E214k(C) or β-tubulin (D).
