Probable core component of multiple cullin-RING-based BCB (BTB-CUL3-BTB) E3 ubiquitin-protein ligase complexes which mediate the ubiquitination and subsequent proteasomal degradation of target proteins (PubMed:13679922). Probably acts as a scaffold protein which may contribute to catalysis through positioning of the substrate and the ubiquitin-conjugating enzyme (PubMed:13679922). Required to target mei-3/katanin for degradation at the meiosis to mitosis transition via its neddylation and deneddylation (PubMed:12781129). Functions in ubiquitin-mediated degradation of CKIs to target cki-1 for degradation (PubMed:12781129). Regulates microtubule stability in the early embryo (PubMed:12781129). In body wall muscles, involved in the organization of myosin thick filaments, likely by regulating the degradation of microtubule severing protein mei-1 downstream of unc-89 (PubMed:22621901). Together with spop-1, may promote the ubiquitination and proteasomal degradation of target bromodomain-containing proteins such as bet-1 (PubMed:34593637). Protein modification; protein ubiquitination. Probable component of multiple cullin-RING-based BCB (BTB-CUL3-BTB) E3 ubiquitin-protein ligase complexes formed by cul-3, rbx-1 and a variable BTB domain-containing protein acting as both, adapter to cullin and substrate recognition component (PubMed:13679922). Interacts with bath-15, bath-40, bath-41, bath-42, C17F4.8, tag-303, D2045.8, F57C2.1, ZC239.15 and B0281.5 (PubMed:13679922). Interacts with mel-26 (via BTB domain) (PubMed:13679922, PubMed:22621901). Interacts with dcn-1 (PubMed:13679922). Highest levels in embryos and lower levels in larvae and adults. Neddylated. Deneddylated via its interaction with the COP9 signalosome (CSN) complex. RNAi-mediated knockdown at L1 larval stage results in the disorganization of myosin thick filaments in adult body wall muscles characterized by the formation of abnormal myosin heavy chain myo-3 aggregates and V-shaped crossing of A-bands (PubMed:22621901). RNAi-mediated knockdown suppresses the age-dependent paralysis and growth arrest induced by exogenous dipeptide repeat protein PR50 (PubMed:34593637). Belongs to the cullin family.