The COP9/signalosome complex is conserved in fission yeast and has a role in S phase

Curr Biol. 1999 Dec 2;9(23):1427-30. doi: 10.1016/s0960-9822(00)80091-3.


The COP9/signalosome complex is conserved from plant to mammalian cells. In Arabidopsis, it regulates the nuclear abundance of COP1, a transcriptional repressor of photomorphogenic development [1] [2]. All COP (constitutive photomorphogenesis) mutants inappropriately express genes that are normally repressed in the dark. Eight subunits (Sgn1-Sgn8) of the homologous mammalian complex have been purified [3] [4]. Several of these have been previously identified through genetic or protein interaction screens. No coherent model for COP9/signalosome function has yet emerged, but a relationship with cell-cycle progression by transcriptional regulation, protein localisation or protein stability is possible. Interestingly, the COP9/signalosome subunits possess domain homology to subunits of the proteasome regulatory lid complex [5] [6]. Database searches indicate that only Sgn5/JAB1 is present in Saccharomyces cerevisiae, precluding genetic analysis of the complex in cell-cycle regulation. Here we identify a subunit of the signalosome in the fission yeast Schizosaccharomyces pombe through an analysis of the DNA-integrity checkpoint. We provide evidence for the conservation of the COP9/signalosome complex in fission yeast and demonstrate that it functions during S-phase progression.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • COP9 Signalosome Complex
  • Cell Division
  • Cell Nucleus / metabolism
  • Checkpoint Kinase 1
  • Conserved Sequence
  • DNA, Fungal / analysis
  • Genes, cdc
  • Humans
  • Immunoblotting
  • Microscopy, Fluorescence
  • Multiprotein Complexes
  • Mutagenesis
  • Peptide Hydrolases
  • Plant Proteins / analysis*
  • Plant Proteins / physiology*
  • Plants
  • Protein Kinases / genetics
  • Proteins*
  • S Phase / physiology*
  • Schizosaccharomyces / chemistry*
  • Schizosaccharomyces / cytology*
  • Schizosaccharomyces / genetics
  • Signal Transduction*


  • DNA, Fungal
  • Multiprotein Complexes
  • Plant Proteins
  • Proteins
  • Protein Kinases
  • Checkpoint Kinase 1
  • Peptide Hydrolases
  • COP9 Signalosome Complex