title: An interaction network of the mammalian COP9 signalosome identifies Dda1 as a core subunit of multiple Cul4-based E3 ligases.
abstract: The COP9 signalosome (CSN) is an evolutionarily conserved macromolecular complex that interacts with cullin-RING E3 ligases (CRLs) and regulates their activity by hydrolyzing cullin-Nedd8 conjugates. The CSN sequesters inactive CRL4(Ddb2), which rapidly dissociates from the CSN upon DNA damage. Here we systematically define the protein interaction network of the mammalian CSN through mass spectrometric interrogation of the CSN subunits Csn1, Csn3, Csn4, Csn5, Csn6 and Csn7a. Notably, we identified a subset of CRL complexes that stably interact with the CSN and thus might similarly be activated by dissociation from the CSN in response to specific cues. In addition, we detected several new proteins in the CRL-CSN interactome, including Dda1, which we characterized as a chromatin-associated core subunit of multiple CRL4 proteins. Cells depleted of Dda1 spontaneously accumulated double-stranded DNA breaks in a similar way to Cul4A-, Cul4B- or Wdr23-depleted cells, indicating that Dda1 interacts physically and functionally with CRL4 complexes. This analysis identifies new components of the CRL family of E3 ligases and elaborates new connections between the CRL and CSN complexes.
authors.affiliation: Swiss Federal Institute of Technology Zürich (ETH), Institute of Biochemistry, 8093 Zürich, Switzerland.
authors.forename: Michael Hans
authors.initials: MH
authors.lastname: Olma
authors.forename: Marcia
authors.initials: M
authors.lastname: Roy
authors.forename: Thierry
authors.initials: T
authors.lastname: Le Bihan
authors.forename: Izabela
authors.initials: I
authors.lastname: Sumara
authors.forename: Sarah
authors.initials: S
authors.lastname: Maerki
authors.forename: Brett
authors.initials: B
authors.lastname: Larsen
authors.forename: Manfredo
authors.initials: M
authors.lastname: Quadroni
authors.forename: Matthias
authors.initials: M
authors.lastname: Peter
authors.forename: Mike
authors.initials: M
authors.lastname: Tyers
authors.forename: Lionel
authors.initials: L
authors.lastname: Pintard
mesh_terms: D000818:Animals; D000075686:COP9 Signalosome Complex; D002453:Cell Cycle; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D044842:Cullin Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008322:Mammals / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism*; D021381:Protein Transport; D020543:Proteome / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*
chemical_list: C114234:CUL4A protein, human; C517832:CUL4B protein, human; D002843:Chromatin; D044842:Cullin Proteins; C541165:DDA1 protein, human; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D021122:Protein Subunits; D020543:Proteome; D044767:Ubiquitin-Protein Ligases; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex