CSN3gen

CSN3gen is a term used in genetic and proteomic resources to refer to the gene that encodes the CSN3 subunit of the COP9 signalosome, or to genetic data associated with that locus. In humans the gene is designated COPS3, standing for COP9 signalosome subunit 3. The CSN3 subunit is one component of the eight-subunit COP9 signalosome, a highly conserved protein complex that regulates protein turnover by modulating the deneddylation of cullin-RING ligases.

Function and mechanism: The COP9 signalosome controls ubiquitin-mediated degradation by removing Nedd8 from cullin proteins, thereby restricting the activity of cullin-based E3 ligases. CSN3 contributes to the structural integrity of the complex and participates in interactions with other subunits. Through these roles, CSN3 influences cellular processes such as cell cycle progression, development, DNA damage response, and adaptation to stress.

Genomic context and expression: The CSN3 (COPS3) gene is conserved across vertebrates and exhibits multiple transcript variants in some species. Expression is widespread, with higher levels in tissues undergoing active protein turnover and during developmental stages in which growth is prominent. In model organisms, perturbation of COP9 subunits can affect viability and growth, illustrating the importance of the CSN3 subunit within the complex.

Clinical and research relevance: Research has explored associations between CSN3/COPS3 expression and disease, including cancer in some studies, but findings are not yet consistent. The COP9 signalosome remains a focus of investigation for its role in regulating protein stability and signaling networks that govern proliferation and genomic integrity. See also COP9 signalosome, COPS3, deneddylation, ubiquitin-proteasome system.

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