May modulate activity of cullin-RING E3 ubiquitin ligase (CRL) complexes (PubMed:21778237). May down-regulate activation of NF-kappa-B (PubMed:15799966). Interacts (via COMM domain) with COMMD1 (via COMM domain). Interacts with RELA, RELB, NFKB1/p105, NFKB2/p100. Interacts with CCDC22, CCDC93, SCNN1B, CUL1, CUL2, CUL3, CUL4A, CUL4B, CUL7. Ubiquitous.