The DEAD-box protein Ded1 modulates translation by the formation and resolution of an eIF4F-mRNA complex.
The translation, localization, and degradation of cytoplasmic mRNAs are controlled by the formation and rearrangement of their mRNPs. The conserved Ded1/DDX3 DEAD-box protein functions in an unknown manner to affect both translation initiation and repression. We demonstrate that Ded1 first functions by directly interacting with eIF4G to assemble a Ded1-mRNA-eIF4F complex, which accumulates in stress granules. After ATP hydrolysis by Ded1, the mRNP exits stress granules and completes translation initiation. Thus, Ded1 functions both as a repressor of translation, by assembling an mRNP stalled in translation initiation, and as an ATP-dependent activator of translation, by resolving the stalled mRNP. These results identify Ded1 as a translation initiation factor that assembles and remodels an intermediate complex in translation initiation.
Pubmed ID: 21925384 RIS Download
Adenosine Triphosphate | Amino Acid Sequence | Cytoplasmic Granules | DEAD-box RNA Helicases | Eukaryotic Initiation Factor-4F | Eukaryotic Initiation Factor-4G | Gene Expression Regulation | Models, Genetic | Molecular Sequence Data | Protein Biosynthesis | RNA, Messenger | Ribonucleoproteins | Saccharomyces cerevisiae Proteins | Sequence Alignment