COP9 signalosome

COP9 (Constitutive photomorphogenesis 9) signalosome structure

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] It was found in all eukaryotic organisms including human; it was first discovered in plants.[2][3] Human COP9 signalosome (total size ~350 kDa) consists of 8 subunits - CSN1, CSN2, CSN3, CSN4, 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]

References

  1. 1 2 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. doi:10.1038/nature13566. PMID 25043011.
  2. Schwechheimer, C (29 November 2004). "The COP9 signalosome (CSN): an evolutionary conserved proteolysis regulator in eukaryotic development.". Biochimica et Biophysica Acta 1695 (1-3): 45–54. doi:10.1016/j.bbamcr.2004.09.023. PMID 15571808.
  3. 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.

Further reading

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