Figure 1

In L6 myotubes, PDCD4 abundance, but not phosphorylation, is sensitive to medium nutrient composition and requires mTORC1 function. L6 Myotubes were incubated in differentiation (Ctl) or starvation medium (serum-free, amino acid-free RPMI medium) for 12 h. They were then harvested (Stv) or refed in the differentiation medium supplemented with DMSO (−) or 50 nM rapamycin (+) for 1 or 3 h. (A) Phosphorylated (ph) and total PDCD4 (Ser67), ph-S6K1 (Thr389) and γ-tubulin were analyzed by immunoblotting. (B and C) phosphorylated and total PDCD4 signals were expressed relative to γ tubulin. Means ± SE of 5–6 independent experiments; bars with different letters differ (P < 0.05).