DCUN1 family contains five proteins which are part of an E3 ubiquitin ligase complex for neddylation. Promotes neddylation of cullin components of E3 cullin-RING ubiquitin ligase complexes. DCNL1 and DCNL2 contain N-terminal UBA domains, DCNL3, DCNL4 and DCNL5 contain unique N-termini that are predicted to be unstructured. In general, the N-termini are thought to govern the subcellular localization of DCNs or their cullin specificity. However, comprehensive evidence in support of this hypothesis is missing, except for DCNL1 and DCNL3.