A direct interaction between DCP1 and XRN1 couples mRNA decapping to 5' exonucleolytic degradation

Nat Struct Mol Biol. 2012 Dec;19(12):1324-31. doi: 10.1038/nsmb.2413. Epub 2012 Nov 11.


The removal of the mRNA 5' cap structure by the decapping enzyme DCP2 leads to rapid 5'→3' mRNA degradation by XRN1, suggesting that the two processes are coordinated, but the coupling mechanism is unknown. DCP2 associates with the decapping activators EDC4 and DCP1. Here we show that XRN1 directly interacts with EDC4 and DCP1 in human and Drosophila melanogaster cells, respectively. In D. melanogaster cells, this interaction is mediated by the DCP1 EVH1 domain and a DCP1-binding motif (DBM) in the XRN1 C-terminal region. The NMR structure of the DCP1 EVH1 domain bound to the DBM reveals that the peptide docks at a conserved aromatic cleft, which is used by EVH1 domains to recognize proline-rich ligands. Our findings reveal a role for XRN1 in decapping and provide a molecular basis for the coupling of decapping to 5'→3' mRNA degradation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Drosophila melanogaster
  • Endopeptidases / chemistry
  • Endopeptidases / metabolism*
  • Exoribonucleases / chemistry
  • Exoribonucleases / metabolism*
  • Humans
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / metabolism*
  • Molecular Sequence Data
  • Proteolysis
  • RNA, Messenger / metabolism*
  • Sequence Homology, Amino Acid


  • Microtubule-Associated Proteins
  • RNA, Messenger
  • Exoribonucleases
  • XRN1 protein, human
  • Endopeptidases
  • dipeptidyl carboxypeptidase

Associated data

  • PDB/2LYD