The COP9 signalosome: at the interface between signal transduction and ubiquitin-dependent proteolysis.
Recently the COP9 signalosome (CSN) has become a focus of interest for many researchers, because of its function at the interface between signal transduction and ubiquitin-dependent proteolysis. It is required for the proper progression of the cell cycle in Schizosaccharomyces pombe and is essential for development in plants and Drosophila. However, its function in mammalian cells remains obscure. Although the CSN shares structural similarities with the 26S proteasome lid complex (LID), its functions seem to be different from that of the LID. A variety of CSN-specific protein-protein interactions have been described in mammalian cells. However, it is currently unclear how many reflect true functions of the complex. Two activities associated with the CSN have been identified so far: a protein kinase and a deneddylase. The CSN-associated kinase phosphorylates transcription factors, which determines their stability towards the ubiquitin system. The associated deneddylase regulates the activity of specific SCF E3 ubiquitin ligases. The CSN thus appears to be a platform connecting signalling with proteolysis.
Bech-Otschir
Dawadschargal
D
Division of Molecular Biology, Department of Surgery, Medical Faculty Charité, Humboldt University, Monbijoustrasse 2, 10117 Berlin, Germany.
Seeger
Michael
M
Dubiel
Wolfgang
W
D000818:Animals; D000075686:COP9 Signalosome Complex; D018797:Cell Cycle Proteins / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D046912:Multiprotein Complexes; D010447:Peptide Hydrolases / Q000378:metabolism / Q000648:ultrastructure; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex; D021122:Protein Subunits; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism*
D018797:Cell Cycle Proteins; D046912:Multiprotein Complexes; D021122:Protein Subunits; D011506:Proteins; D016159:Tumor Suppressor Protein p53; D025801:Ubiquitin; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease