This gene encodes an essential regulator of Cullin-RING ubiquitin ligases, which are in involved in ubiquitinylation of proteins degraded by the Ub proteasome system. The encoded protein binds to unneddylated cullin-RING box protein complexes and acts as an inhibitor of cullin neddylation and of Skp1, cullin, and F box ubiquitin ligase complex assembly and activity. In mammalian cell culture, this protein predominantly localizes to the cytoplasm. Knockdown of this gene in preadipocytes results in blocked adipogenesis. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2016].