{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n The COP9 signalosome (often abbreviated as CSN) is a highly conserved, multi‐subunit protein complex that plays a central role in regulating protein homeostasis by modulating the activity of cullin–RING ubiquitin ligases (CRLs). By removing the ubiquitin‐like modifier NEDD8 from cullins, the complex controls the stability and turnover of a wide range of proteins involved in cell cycle progression, DNA damage repair, and stress responses. Under conditions of cellular stress and oncogenic signaling, for example, interactions between regulatory proteins such as Myeov2 and the COP9 signalosome help govern the subnuclear localization and neddylation status of key molecules, thereby influencing downstream pathways including p53‐mediated stress responses."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In addition to its role in controlling post‐translational modifications, the COP9 signalosome is integral to the maintenance of genomic integrity, as it fine‐tunes CRL activity during the DNA damage response, ensuring that proteins implicated in repair processes are appropriately regulated."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": " Comparative studies spanning diverse eukaryotic organisms have highlighted that certain subunits of the complex, notably CSN2 and CSN5, are evolutionarily highly constrained, underlining their importance in preserving cellular function across species."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Moreover, recent advances have expanded our understanding of this complex through the identification of an additional integral component, CSNAP, which binds to multiple CSN subunits and contributes to the overall structural and functional integrity of the signalosome. This discovery further emphasizes the complexity and versatility of the COP9 signalosome in regulating cell proliferation and morphology."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Together, these findings demonstrate that the COP9 signalosome functions as a master regulator of cellular processes through its role in post‐translational modification, protein turnover, and the cellular response to stress, making it a key player in maintaining cellular homeostasis.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Manato Ebina, Fuminori Tsuruta, Megumi C Katoh, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Myeloma overexpressed 2 (Myeov2) regulates L11 subnuclear localization through Nedd8 modification."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "PLoS One (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1371/journal.pone.0065285"}], "href": "https://doi.org/10.1371/journal.pone.0065285"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23776465"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23776465"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Dudley Chung, Graham Dellaire "}, {"type": "b", "children": [{"type": "t", "text": "The Role of the COP9 Signalosome and Neddylation in DNA Damage Signaling and Repair."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biomolecules (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.3390/biom5042388"}], "href": "https://doi.org/10.3390/biom5042388"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "26437438"}], "href": "https://pubmed.ncbi.nlm.nih.gov/26437438"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Emanuel Barth, Ron Hübler, Aria Baniahmad, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The Evolution of COP9 Signalosome in Unicellular and Multicellular Organisms."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Genome Biol Evol (2016)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1093/gbe/evw073"}], "href": "https://doi.org/10.1093/gbe/evw073"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "27044515"}], "href": "https://pubmed.ncbi.nlm.nih.gov/27044515"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Shelly Rozen, Maria G Füzesi-Levi, Gili Ben-Nissan, et al. "}, {"type": "b", "children": [{"type": "t", "text": "CSNAP Is a Stoichiometric Subunit of the COP9 Signalosome."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Cell Rep (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.celrep.2015.09.021"}], "href": "https://doi.org/10.1016/j.celrep.2015.09.021"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "26456823"}], "href": "https://pubmed.ncbi.nlm.nih.gov/26456823"}]}]}]}