Required for neddylation of cullin components of SCF-type E3 ubiquitin ligase complexes. Neddylation of cullins play an essential role in the regulation of SCF-type complexes activity. Does not act by preventing deneddylation, but rather facilitates neddylation, possibly by acting with rbx-1 to recruit the Nedd8-charged E2 enzyme to the cullin component of SCF-type complexes (By similarity). Interacts with the cullin cul-3. Interacts with ubiquitin via its UBA-like domain. Interacts with ned-8/nedd8 (By similarity).