The COP9 complex is conserved between plants and mammals and is related to the 26S proteasome regulatory complex

Curr Biol. 1998 Jul 30-Aug 13;8(16):919-22. doi: 10.1016/s0960-9822(07)00372-7.


The COP9 complex, genetically identified in Arabidopsis as a repressor of photomorphogenesis, is composed of multiple subunits including COP9, FUS6 (also known as COP11) and the Arabidopsis JAB1 homolog 1 (AJH1) ([1-3]; unpublished observations). We have previously demonstrated the existence of the mammalian counterpart of the COP9 complex and purified the complex by conventional biochemical and immunoaffinity procedures [4]. Here, we report the molecular identities of all eight subunits of the mammalian COP9 complex. We show that the COP9 complex is highly conserved between mammals and higher plants, and probably among most multicellular eukaryotes. It is not present in the single-cell eukaryote Saccharomyces cerevisiae, however. All of the subunits of the COP9 complex contain structural features that are also present in the components of the proteasome regulatory complex and the translation initiation factor eIF3 complex. Six subunits of the COP9 complex have overall similarity with six distinct non-ATPase regulatory subunits of the 26S proteasome, suggesting that the COP9 complex and the proteasome regulatory complex are closely related in their evolutionary origin. Subunits of the COP9 complex include regulators of the Jun N-terminal kinase (JNK) and c-Jun, a nuclear hormone receptor binding protein and a cell-cycle regulator. This suggests that the COP9 complex is an important cellular regulator modulating multiple signaling pathways.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / genetics
  • Amino Acid Sequence
  • Animals
  • Arabidopsis / genetics
  • Arabidopsis Proteins*
  • Brassica / genetics
  • COP9 Signalosome Complex
  • Calcium-Calmodulin-Dependent Protein Kinases / chemistry
  • Chromatography, Affinity
  • Conserved Sequence
  • Evolution, Molecular
  • GTP-Binding Proteins*
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • JNK Mitogen-Activated Protein Kinases
  • Mammals
  • Mitogen-Activated Protein Kinases*
  • Multiprotein Complexes
  • Peptide Hydrolases / chemistry
  • Peptide Hydrolases / genetics*
  • Phylogeny*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Plant Proteins / isolation & purification
  • Proteasome Endopeptidase Complex*
  • Proteins*
  • Repressor Proteins*
  • Signal Transduction


  • Arabidopsis Proteins
  • CSN1 protein, Arabidopsis
  • GPS1 protein, human
  • Intracellular Signaling Peptides and Proteins
  • Multiprotein Complexes
  • Plant Proteins
  • Proteins
  • Repressor Proteins
  • Calcium-Calmodulin-Dependent Protein Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • Peptide Hydrolases
  • COP9 Signalosome Complex
  • Proteasome Endopeptidase Complex
  • ATP dependent 26S protease
  • Adenosine Triphosphatases
  • GTP-Binding Proteins

Associated data

  • GENBANK/AF071312
  • GENBANK/AF071313
  • GENBANK/AF071314
  • GENBANK/AF071315
  • GENBANK/AF071316
  • GENBANK/AF071317