| First Author | Figueiredo VC | Year | 2019 |
| Journal | Am J Physiol Cell Physiol | Volume | 317 |
| Issue | 6 | Pages | C1247-C1255 |
| PubMed ID | 31596607 | Mgi Jnum | J:282001 |
| Mgi Id | MGI:6379200 | Doi | 10.1152/ajpcell.00380.2019 |
| Citation | Figueiredo VC, et al. (2019) Phosphorylation of eukaryotic initiation factor 4E is dispensable for skeletal muscle hypertrophy. Am J Physiol Cell Physiol 317(6):C1247-C1255 |
| abstractText | The eukaryotic initiation factor 4E (eIF4E) is a major mRNA cap-binding protein that has a central role in translation initiation. Ser(209) is the single phosphorylation site within eIF4E and modulates its activity in response to MAPK pathway activation. It has been reported that phosphorylation of eIF4E at Ser(209) promotes translation of key mRNAs, such as cyclin D1, that regulate ribosome biogenesis. We hypothesized that phosphorylation at Ser(209) is required for skeletal muscle growth in response to a hypertrophic stimulus by promoting ribosome biogenesis. To test this hypothesis, wild-type (WT) and eIF4E knocked-in (KI) mice were subjected to synergist ablation to induce muscle hypertrophy of the plantaris muscle as the result of mechanical overload; in the KI mouse, Ser(209) of eIF4E was replaced with a nonphosphorylatable alanine. Contrary to our hypothesis, we observed no difference in the magnitude of hypertrophy between WT and KI groups in response to 14 days of mechanical overload induced by synergist ablation. Similarly, the increases in cyclin D1 protein levels, ribosome biogenesis, and translational capacity did not differ between WT and KI groups. Based on these findings, we conclude that phosphorylation of eIF4E at Ser(209) is dispensable for skeletal muscle hypertrophy in response to mechanical overload. |
