DNA damage-binding protein 2 (DDB2) is required for DNA repair. It binds to DDB1 to form the UV-damaged DNA-binding protein complex (the UV-DDB complex). The UV-DDB complex may recognize UV-induced DNA damage and recruit proteins of the nucleotide excision repair pathway (the NER pathway) to initiate DNA repair []. It is also involved in the initiation of nucleotide excision repair via an ubiquitin ligase complex together with DDB1 and CUL4A (cullin 4A) [].
Ubiquitin-specific peptidase 24 (USP24, MEROPS identifier C19.047) is a de-ubiquitinating enzyme that is associated with late-onset Parkinson's Disease []. The enzyme is known to remove ubiquitin from damage-specific DNA-binding protein 2 (DDB2), increasing its stability. DDB2 is involved in DNA damage recognition in the nucleotide excision repair pathway, and is a component of an E3 ligase that targets XPC, histones and DDB2 itself []. USP24 also de-ubiquitinates p53, and cells are resistant to apoptosis following UV irradiation if USP24 is depleted because p53 is stabilized []. Single-nucleotide polymorphisms of the USP24 gene have been identified in lung cancer malignancy and could be diagnostic markers for the disease []. The USP24 gene is up-regulated when the USP9X gene is down-regulated by shRNA, leading to increased survival of B-cell myeloma cells []. USP24 positively regulates ferritinophagy, a process in which ferritin is degraded in lysosomes and releases free iron [].
This entry includes eIF3m and COPS7A/B. eIF3m is a component of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is involved in protein synthesis and, together with other initiation factors, stimulates binding of mRNA and methionyl-tRNAi to the 40S ribosome []. The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].
The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].In mammals, the CSN7 subunit is encoded by two similar genes, CSN7a and CSN7b []. This entry represents subunit CSN7b.
The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].This entry includes the COP9 signalosome complex (CSN) subunits 2 and 10. Subunit 10 is found only in some yeasts and is uncharacterized.
The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].This entry includes the COP9 signalosome complex (CSN) subunit 3 (CSN3). Interactions have been identified between CSN3 and IKKgamma, which prevents activation of transcription factor nuclear factor kappaB (NF-kappaB) []; and the Int-6 protein subunit of the eIF3 translation initiation factor [].
The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].In the complex, CSN8, which is the smallest subunit, probably interacts directly with CSN3, CSN4 and CSN7 (CSN7A or CSN7B). It is necessary for assembly of the complex []. CSN8 plays an important role in maintaining the proper duration of the G1 phase of the cell cycle [].
The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].This entry includes the COP9 signalosome complex (CSN) subunit 4 (CSN4). CSN4 also binds to the AAA+ ATPase torsinA, and CSN4 and torsinA in turn stabilize snapin, which is phosphorylated by protein kinase D, and stonin 2, which is neddylated. A mutation in torsinA leads to DYT1 dystonia, and overexpression of the mutant leads to a reduction of stonin 2 expression, suggesting that the mutant compromises the role of torsinA in protein stabilization and synaptic vesicle recycling [].
The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].In mammals, the CSN7 subunit is encoded by two similar genes, CSN7A and CSN7B []. This entry irepresents the COP9 signalosome complex (CSN) subunit 7a (CSN7A). Either CSN7A or CSN7B can be a component of CSN. CSN7A binds to polyamine-modulated factor 1, and each competes with the other for binding to NF-E2 related factor-2 (Nrf-2). Binding to Nrf-2 regulates transcription of spermidine/spermine N(1)-acetyltransferase []. CSN7A also binds the Int-6 protein subunit of the eIF3 translation initiation factor []; and protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53, resulting in their degradation by the ubiquitin-26S proteasome system [].
The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].COP9 signalosome complex subunit 5 (Rri1, CSN5 or JAB1) is a metallo-isopeptidase (MEROPS identifier M67.002) that releases the ubiquitin-like protein Nedd8 from the Cul1 subunit of SCF ubiquitin ligases []. Rri1 binds a zinc ion via the histidines in an HXH motif and an aspartic acid C-terminal to this motif []. This entry includes CSN5 homologues from yeast to human.
The COP9 signalosome (CSN) is a conserved protein complex that regulates the ubiquitin (Ubl) conjugation pathway by mediating the deneddylation of the cullin subunits of SCF-type E3 ligase complexes [], which leads to a decrease in Ubl ligase activity of SCF-type complexes such as SCF, CSA or DDB2 []. Protein kinases CK2 and D, which phosphorylate proteins such as cJun and p53 resulting in their degradation by the ubiquitin-26S proteasome system, also binds to CSN [, ]. The mammalian CSN typically consistis of eight subunits designated CSN1-CSN8. The fission yeast possesses a smaller version of the CSN, consisting only of six subunits, whereas a more distant CSN-like complex has been described in Saccharomyces cerevisiae [].CSN6 (COP9 signalosome subunit 6; COP9 subunit 6; MOV34 homolog, 34 kD; MEROPS identifier M67.972) is one of the eight subunits of COP9 signalosome. CSN6 is an MPN-domain protein that directly interacts with the MPN+-domain subunit CSN5 []. It is cleaved during apoptosis by activated caspases. CSN6 processing occurs in CSN/CRL (cullin-RING Ub ligase) complexes and is followed by the cleavage of Rbx1, the direct interaction partner of CSN6 []. CSN6 cleavage enhances CSN-mediated deneddylating activity (i.e. cleavage of ubiquitin-like protein Nedd8 (neural precursor cell expressed, developmentally downregulated 8)) in the cullin 1 in cells []. The cleavage of Rbx1 and increased deneddylation of cullins inactivate CRLs and presumably stabilize pro-apoptotic factors for final apoptotic steps. While CSN6 shows a typical MPN metalloprotease fold, it lacks the canonical JAMM motif, and therefore does not show catalytic isopeptidase activity.
