The COP9 signalosome

Annu Rev Cell Dev Biol. 2003;19:261-86. doi: 10.1146/annurev.cellbio.19.111301.112449.


The COP9 signalosome (CSN) is composed of eight distinct subunits and is highly homologous to the lid sub-complex of the 26S proteasome. CSN was initially defined as a repressor of photomorphogenesis in Arabidopsis, and it has now been found to participate in diverse cellular and developmental processes in various eukaryotic organisms. Recently, CSN was revealed to have a metalloprotease activity centered in the CSN5/Jab1 subunit, which removes the post-translational modification of a ubiquitin-like protein, Nedd8/Rub1, from the cullin component of SCF ubiquitin E3 ligase (i.e., de-neddylation). In addition, CSN is associated with de-ubiquitination activity and protein kinase activities capable of phosphorylating important signaling regulators. The involvement of CSN in a number of cellular and developmental processes has been attributed to its control over ubiquitin-proteasome-mediated protein degradation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Arabidopsis Proteins
  • COP9 Signalosome Complex
  • Humans
  • Metalloendopeptidases / metabolism
  • Multiprotein Complexes
  • NEDD8 Protein
  • Peptide Hydrolases
  • Phosphorylation
  • Protein Subunits / metabolism*
  • Protein Transport / physiology
  • Proteins / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Signal Transduction / physiology*
  • Ubiquitin-Protein Ligase Complexes / metabolism*
  • Ubiquitins / metabolism*


  • Arabidopsis Proteins
  • Multiprotein Complexes
  • NEDD8 Protein
  • NEDD8 protein, human
  • Protein Subunits
  • Proteins
  • RUB1 protein, Arabidopsis
  • Saccharomyces cerevisiae Proteins
  • Ubiquitins
  • Ubiquitin-Protein Ligase Complexes
  • Peptide Hydrolases
  • COP9 Signalosome Complex
  • Metalloendopeptidases
  • Rri1 protein, S cerevisiae