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The human COP9 signalosome protects ubiquitin-conjugating enzyme 3 (UBC3/Cdc34) from beta-transducin repeat-containing protein (betaTrCP)-mediated degradation.


The COP9 signalosome (CSN) is an essential multisubunit complex that regulates the activity of cullin-RING ubiquitin ligases by removing the ubiquitin-like peptide NEDD8 from cullins. Here, we demonstrate that the CSN can affect other components of the ubiquitination cascade. Down-regulation of human CSN4 or CSN5 induced proteasome-mediated degradation of the ubiquitin-conjugating enzyme UBC3/Cdc34. UBC3 was targeted for ubiquitination by the cullin-RING ubiquitin ligase SCF(betaTrCP). This interaction required the acidic C-terminal extension of UBC3, which is absent in ubiquitin-conjugating enzymes of the UBCH5 family. Conversely, the UBC3 acidic domain was sufficient to impart sensitivity to SCF(betaTrCP)-mediated ubiquitination to UBCH5 enzymes. Our work indicates that the CSN is necessary to ensure the stability of selected ubiquitin-conjugating enzymes and uncovers a novel pathway of regulation of ubiquitination processes.

Pubmed ID: 20378537


  • Fernandez-Sanchez ME
  • Sechet E
  • Margottin-Goguet F
  • Rogge L
  • Bianchi E


The Journal of biological chemistry

Publication Data

June 4, 2010

Associated Grants


Mesh Terms

  • Anaphase-Promoting Complex-Cyclosome
  • Cell Line
  • Down-Regulation
  • HeLa Cells
  • Humans
  • Lentivirus
  • Multiprotein Complexes
  • Oligonucleotides
  • Peptide Hydrolases
  • Plasmids
  • RNA
  • Reverse Transcriptase Polymerase Chain Reaction
  • Substrate Specificity
  • Transducin
  • Ubiquitin
  • Ubiquitin-Conjugating Enzymes
  • Ubiquitin-Protein Ligase Complexes