Anti-Cullin-4A from rabbit, purified by affinity chromatography

Cullin-4A (UniProt Q13619; also known as CUL-4A) is encoded by the CUL4A gene (Gene ID 8451) in human. CUL-4A belongs to the cullin family of hydrophobic proteins that functions as the scaffold component of E3 ubiquitin ligase complexes. CUL-4A interacts with DNA damage binding protein 1 (DDB1) and ring of cullins (ROC1) to assemble the E3 complex, where DDB1 acts a linker protein for CUL4 and recruits substrates to the CUL4-ROC1 catalytic core through interaction with a subset of WD40 proteins. At least 90 DDB1-binding WD40 (DWD) proteins (also known as DCAF for Ddb1- and Cul4-associated factors and CDW for CUL4 and DDB1-associated WD40 repeats) are known, suggesting a large number of potential substrates for CUL4-ROC1 ligase complexes. CUL4-ROC1 E3 ligase complexes play important roles in cell cycle, DNA replication, genomic stability, haematopoiesis, and spermatogenesis. CUL-4A is highly expressed in testis and spleen, while poor expression is found in lung, liver, thymus, small intestine, and muscular tissues. CUL4A gene amplification has been demonstrated in many kinds of tumors, including hepatocellular carcinomas (HCC), squamous cell carcinomas, and adrenocortical carcinoma. CUL4A silencing is reported to suppress the motility of HCC cells and reverse their epithelial-mesenchymal transition (EMT) tendency.