May modulate activity of cullin-RING E3 ubiquitin ligase (CRL) complexes (PubMed:21778237). Down-regulates activation of NF-kappa-B. Interacts (via COMM domain) with COMMD1 (via COMM domain). Interacts with RELA, RELB, NFKB1/p105. Interacts with CCDC22, CCDC93, SCNN1B, CUL2, CUL3, CUL4A, CUL5, CUL7. Ubiquitous.