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COP9 Sygnalosome ( CONSTITUTIVE PHOTOMORPHOGENIC 9) referred more often abbreviated as CSN ( COP9 signalosome called ) is a multiprotein complex nuclear commonly occurring Eucariotes . The results of many diverse studies have shown CSN participate in a wide range of vital processes , such as photomorhogenesis , regulation of cell cycle or cell differentiation . Increasingly complex COP9 signalosome is associated with the control of the ubiquitin mediated protein degradation . Such conclusions based on the interaction of this complex with three ubiquitin ligases : SCF ( SKP1 , Cullin/CDC53 , F - BOX) , MDM2 ( MURINE DUBLE MINUTE 2 ) , COP1 ( CONSTITUTIVE PHOTOMORPHOGENIC 1). Additionally described are manifestations of activity CSN protein phosphorylation (but not directly ), and detaching the protein NEDD8 ( Precursor NEURAL CELL DOWN - Expressed Developmentally -regulated 8) ( denedylacja ) , which processes may affect the stability of the complex of proteins interacting with CSN . In addition, calls to his participation in the transport of ubiquitinated proteins from the nucleus to the cytoplasm and their degradation by the 26S proteasome . CSN made ​​up of eight sub-units , two of which contain the MPN (Mpr1 , Pad1p , N- terminus) and the other PCI domain ( proteasome , COP9 , eIF3 ) . The latter is also a feature of the two other multisubunit proteins such as the 26S proteasome and the translation initiation factor eIF3 . This fact , as well as others described in the article observations suggest the interaction of these three complexes in multi-level control of protein stability .

The Editorial Board
Andrzej Łukaszyk - przewodniczący, Zofia Bielańska-Osuchowska, Szczepan Biliński, Mieczysław Chorąży, Aleksander Koj, Włodzimierz Korochoda, Leszek Kuźnicki, Aleksandra Stojałowska, Lech Wojtczak

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