DCUN1D2 (defective in cullin neddylation 1 domain containing 2) is an E3 ubiquitin ligase component that catalyzes NEDD8 conjugation to cullins, a critical post-translational modification regulating SCF complex activity. The protein transfers NEDD8 from acetylated E2 enzymes to cullin C-terminal RBX complexes, thereby controlling ubiquitin-mediated protein degradation pathways. DCUN1D2 localizes to both nuclear and cytoplasmic compartments where it binds cullin family proteins and ubiquitin-like molecules 1. Beyond its neddylation function, DCUN1D2 is upregulated during T-cell cycle arrest induced by DNA methyltransferase inhibitors, suggesting a role in growth suppression 1. In cancer contexts, DCUN1D2 has been identified as a candidate gene in multicentric glioblastoma with altered expression patterns correlating with worse prognosis compared to solitary tumors 2. However, studies in mice demonstrate DCUN1D2 is dispensable for spermatogenesis and male fertility, indicating tissue-specific functional requirements 3. The gene's involvement in cell cycle regulation through neddylation-dependent cullin modulation positions it as a potential therapeutic target in cancer, though its broader clinical significance remains under investigation.