Fig. 3

Anabolic pathway leading to muscle growth. Insulin or IGF1 binds to the IGF1R and activates IRS-1 which leads to PI3K-AKT-mTOR pathway activation. AKT activates IKK inhibitor and further inhibits the NF-kB pathway, which is implicated in muscle atrophy induction. Furthermore, AKT also negatively regulates the FoxO protein that is responsible for protein degradation. Besides AKT, the mTOR pathway is also activated by nutrients, leading to phosphorylation of S6K that induces protein synthesis and muscle growth. IGF1, Insulin-like growth factor 1; IGF1R, IGF1 receptor; IRS-1, Insulin receptor substrate 1; and OXPHOS, Oxidative phosphorylation. The dashed lines indicate inhibited pathways