May modulate activity of cullin-RING E3 ubiquitin ligase (CRL) complexes (By similarity). Negatively regulates cell proliferation. Negatively regulates cell cycle G2/M phase transition probably by transactivating p21/CDKN1A through the p53/TP53-independent signaling pathway (PubMed:12620924). Involved in kidney proximal tubule morphogenesis (PubMed:24515317). Down-regulates activation of NF-kappa-B (By similarity). Interacts (via COMM domain) with COMMD1 (via COMM domain). Expressed in the zona fasciculata and medulla of the adrenal gland; expressed in kidney proximal tubules. Basal expression is higher in hypertensive than in normotensive animals.