title: The COP9/signalosome complex is conserved in fission yeast and has a role in S phase.
abstract: 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.
authors.affiliation: MRC Cell Mutation Unit, The University of Sussex, Brighton, BN1 9RR, UK.
authors.forename: K E
authors.initials: KE
authors.lastname: Mundt
authors.forename: J
authors.initials: J
authors.lastname: Porte
authors.forename: J M
authors.initials: JM
authors.lastname: Murray
authors.forename: C
authors.initials: C
authors.lastname: Brikos
authors.forename: P U
authors.initials: PU
authors.lastname: Christensen
authors.forename: T
authors.initials: T
authors.lastname: Caspari
authors.forename: I M
authors.initials: IM
authors.lastname: Hagan
authors.forename: J B
authors.initials: JB
authors.lastname: Millar
authors.forename: V
authors.initials: V
authors.lastname: Simanis
authors.forename: K
authors.initials: K
authors.lastname: Hofmann
authors.forename: A M
authors.initials: AM
authors.lastname: Carr
mesh_terms: D000075686:COP9 Signalosome Complex; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D000071877:Checkpoint Kinase 1; D017124:Conserved Sequence; D004271:DNA, Fungal / Q000032:analysis; D018816:Genes, cdc; D006801:Humans; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D046912:Multiprotein Complexes; D016296:Mutagenesis; D010447:Peptide Hydrolases; D010940:Plant Proteins / Q000032:analysis* / Q000502:physiology*; D010944:Plants; D011494:Protein Kinases / Q000235:genetics; D011506:Proteins; D016196:S Phase / Q000502:physiology*; D012568:Schizosaccharomyces / Q000737:chemistry* / Q000166:cytology* / Q000235:genetics; D015398:Signal Transduction
chemical_list: D004271:DNA, Fungal; D046912:Multiprotein Complexes; D010940:Plant Proteins; D011506:Proteins; D011494:Protein Kinases; D000071877:Checkpoint Kinase 1; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex