Binding of a novel SMG-1-Upf1-eRF1-eRF3 complex (SURF) to the exon junction complex triggers Upf1 phosphorylation and nonsense-mediated mRNA decay.

Nonsense-mediated mRNA decay (NMD) is a surveillance mechanism that degrades mRNA containing premature termination codons (PTCs). In mammalian cells, recognition of PTCs requires translation and depends on the presence on the mRNA with the splicing-dependent exon junction complex (EJC). While it is known that a key event in the triggering ...
of NMD is phosphorylation of the trans-acting factor, Upf1, by SMG-1, the relationship between Upf1 phosphorylation and PTC recognition remains undetermined. Here we show that SMG-1 binds to the mRNA-associated components of the EJC, Upf2, Upf3b, eIF4A3, Magoh, and Y14. Further, we describe a novel complex that contains the NMD factors SMG-1 and Upf1, and the translation termination release factors eRF1 and eRF3 (SURF). Importantly, an association between SURF and the EJC is required for SMG-1-mediated Upf1 phosphorylation and NMD. Thus, the SMG-1-mediated phosphorylation of Upf1 occurs on the association of SURF with EJC, which provides the link between the EJC and recognition of PTCs and triggers NMD.
Mesh Terms:
Codon, Nonsense, Exons, HeLa Cells, Humans, Metalloendopeptidases, Models, Biological, Multienzyme Complexes, Peptide Termination Factors, Phosphorylation, Protein Binding, Protein Biosynthesis, Protein Kinases, RNA, Messenger, RNA-Binding Proteins, Ribonucleoproteins, Trans-Activators, Transcription Factors, Transfection
Genes Dev.
Date: Feb. 01, 2006
Download Curated Data For This Publication
154024
Switch View:
  • Interactions 29