Staufen1 and UPF1 exert opposite actions on the replacement of the nuclear cap-binding complex by eIF4E at the 5' end of mRNAs.

ABSTRACT: Newly synthesized mRNAs are exported from the nucleus to cytoplasm with a 5'-cap structure bound by the nuclear cap-binding complex (CBC). During or after export, the CBC should be properly replaced by cytoplasmic cap-binding protein eIF4E for efficient protein synthesis. Nonetheless, little is known about how the replacement takes place. Here, we show that double-stranded RNA-binding protein staufen1 (STAU1) promotes efficient replacement by facilitating an association between the CBC-importin α complex and importin β. Our transcriptome-wide analyses and artificial tethering experiments also reveal that the replacement occurs more efficiently when an mRNA associates with STAU1. This event is inhibited by a key nonsense-mediated mRNA decay factor, UPF1, which directly interacts with STAU1.

SUBMITTER: Jeong K 

PROVIDER: S-EPMC6753478 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature