NEDD8　is　a　member　of　the　ubiquitin-like　proteins.　The　overall　structure　of　NEDD8　is　quite　similar　to　ubiquitin.　Covalent　conjugation　of　NEDD8　to　proteins　at　the　post-translational　level　is　called　Neddylation.　Neddylation　occurs　similarly　to　ubiquitination　and　need　enzyme　cascades　involving　E1,　E2　and　E3.　Neddylation　has　been　demonstrated　to　be　essential　to　maintain　the　ubiquitin　ligase　activity　of　Cullin-Roc　based　E3　ligases.　Compared　with　the　ubiquitination　which　was　widely　studied　in　the　past　two　decades,　few　substrates　were　identified　for　Neddylation　and　the　physiological　functions　of　Neddylation　need　further　investigations.　The　current　progress　of　function　and　regulation　of　protein　Neddylation　will　be　reviewed.