NEDD8 is part of the ubiquitin family. Human NEDD8 shares 60 % AA sequence homology to ubiquitin. The NEDD8 system is essential for the regulation of protein degradation pathways involved in cell cycle progression, morphogenesis and tumorigenesis. NEDD8 is involved in cell cycle control and embryogenesis. Covalent attachment to its substrates requires prior activation by the E-1 complex UbE1c- appbp1 and linkage to the E-2 enzyme UbE2m. Attachment of NEDD8 to cullins activates their associated E-3 ubiquitin ligase activity, and thus promotes polyubiquitination and proteasomal degradation of cyclins and other regulatory proteins Synonyms: Nedd-8, FLJ43224, MGC104393, MGC125896, MGC125897, NEDD8, Ubiquitin-like protein Nedd8, Neddylin, Neural precursor cell expressed developmentally down-regulated protein 8