COP9 (Constitutive photomorphogenesis 9) signalosome (CSN) is a protein complex with isopeptidase activity. It catalyses the hydrolysis of NEDD8 protein from the cullin subunit of Cullin-RING ubiquitin ligases (CRL). Therefore, it is responsible for CRL deneddylation – at the same time, it is able to bind denedyllated cullin-RING complex and retain them in deactivated form. COP9 signalosome thus serves as a sole deactivator of CRLs.[1] The complex was originally identified in plants,[2][3] and subsequently found in all eukaryotic organisms including human. [4] [5] Human COP9 signalosome (total size ~350 kDa) consists of 8 subunits - CSN1, CSN2, CSN3, CSN4, CSN5, CSN6, CSN7 (COPS7A, COPS7B), CSN8. All are essential for full function of the complex and mutation in some of them is lethal in mice.[1]
- ^ a b Lingaraju, GM; Bunker, RD; Cavadini, S; Hess, D; Hassiepen, U; Renatus, M; Fischer, ES; Thomä, NH (14 August 2014). "Crystal structure of the human COP9 signalosome". Nature. 512 (7513): 161–5. Bibcode:2014Natur.512..161L. doi:10.1038/nature13566. PMID 25043011. S2CID 205239748.
- ^ Wei, Ning; Chamovitz, Daniel A.; Deng, Xing-Wang (1994). "Arabidopsis COP9 is a component of a novel signaling complex mediating light control of development". Cell. 78 (1): 117–124. doi:10.1016/0092-8674(94)90578-9. ISSN 0092-8674. PMID 8033203. S2CID 205021135.
- ^ Chamovitz, Daniel A; Wei, Ning; Osterlund, Mark T; von Arnim, Albrecht G; Staub, Jeffrey M; Matsui, Minami; Deng, Xing-Wang (1996). "The COP9 Complex, a Novel Multisubunit Nuclear Regulator Involved in Light Control of a Plant Developmental Switch". Cell. 86 (1): 115–121. doi:10.1016/S0092-8674(00)80082-3. ISSN 0092-8674. PMID 8689678.
- ^ Seeger, M (1 April 1998). "A novel protein complex involved in signal transduction possessing similarities to 26S proteasome subunits". The FASEB Journal. 12 (6): 469–478. doi:10.1096/fasebj.12.6.469. PMID 9535219. S2CID 25424324.
- ^ Wei, N; Serino, G; Deng, XW (December 2008). "The COP9 signalosome: more than a protease". Trends in Biochemical Sciences. 33 (12): 592–600. doi:10.1016/j.tibs.2008.09.004. PMID 18926707.