COPS4
Description
The COPS4 (COP9 signalosome subunit 4) is a protein-coding gene located on chromosome 4.
COPS4, also known as Signalosome subunit 4 or JAB1-containing signalosome subunit 4, is a protein encoded by the COPS4 gene in humans. It is one of eight subunits that make up the COP9 signalosome (CSN), a highly conserved protein complex. The CSN is functionally similar to the 19S regulatory particle of the 26S proteasome and acts as a crucial regulator in various signaling pathways. The CSN interacts with SCF-type E3 ubiquitin ligases, acting as a positive regulator of their activity.
COPS4 is a subunit of the COP9 signalosome complex (CSN), a critical regulator of various cellular and developmental processes. The CSN complex plays a vital role in the ubiquitin (Ubl) conjugation pathway, specifically by mediating the deneddylation of cullin subunits within SCF-type E3 ligase complexes. This deneddylation process results in a decrease in the Ubl ligase activity of SCF-type complexes, including SCF, CSA, and DDB2. Furthermore, COPS4 is involved in the deneddylation of non-cullin subunits like STON2. The CSN complex also participates in the phosphorylation of proteins such as p53/TP53, c-jun/JUN, IkappaBalpha/NFKBIA, ITPK1, IRF8/ICSBP, and SNAPIN, potentially through its association with CK2 and PKD kinases. CSN-dependent phosphorylation of TP53 and JUN promotes and protects degradation by the Ubl system, respectively.
COPS4 is also known as CSN4, SGN4.
Associated Diseases
- hemoglobin D disease
- hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
- dominant beta-thalassemia
- hemoglobin E disease
