| First Author | Stitt TN | Year | 2004 |
| Journal | Mol Cell | Volume | 14 |
| Issue | 3 | Pages | 395-403 |
| PubMed ID | 15125842 | Mgi Jnum | J:90504 |
| Mgi Id | MGI:3044029 | Doi | 10.1016/s1097-2765(04)00211-4 |
| Citation | Stitt TN, et al. (2004) The IGF-1/PI3K/Akt pathway prevents expression of muscle atrophy-induced ubiquitin ligases by inhibiting FOXO transcription factors. Mol Cell 14(3):395-403 |
| abstractText | Skeletal muscle size depends upon a dynamic balance between anabolic (or hypertrophic) and catabolic (or atrophic) processes. Previously, no link between the molecular mediators of atrophy and hypertrophy had been reported. We demonstrate a hierarchy between the signals which mediate hypertrophy and those which mediate atrophy: the IGF-1/PI3K/Akt pathway, which has been shown to induce hypertrophy, prevents induction of requisite atrophy mediators, namely the muscle-specific ubiquitin ligases MAFbx and MuRF1. Moreover, the mechanism for this inhibition involves Akt-mediated inhibition of the FoxO family of transcription factors; a mutant form of FOXO1, which prevents Akt phosphorylation, thereby prevents Akt-mediated inhibition of MuRF1 and MAFbx upregulation. Our study thus defines a previously uncharacterized function for Akt, which has important therapeutic relevance: Akt is not only capable of activating prosynthetic pathways, as previously demonstrated, but is simultaneously and dominantly able to suppress catabolic pathways, allowing it to prevent glucocorticoid and denervation-induced muscle atrophy. |
