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) (PubMed:15799966). Interacts with RELA, RELB, NFKB1/p105. Interacts with CCDC22, CCDC93, SCNN1B, CUL1, CUL2, CUL3, CUL4A, CUL4B, CUL5 (PubMed:15799966, PubMed:21778237, PubMed:23563313, PubMed:23637203, PubMed:25355947, PubMed:28892079). Widely expressed with highest expression in thyroid.