NEDD8 transferases catalyse the transfer of the ubiquitin-like protein NEDD8 from one substrate to another. They include NEDD8 conjugating (E2) enzymes and NEDD8 ligase (E3) enzymes, which act sequentially in a process analogous to ubiquitination, and result in covalent attachment of NEDD8 to target proteins. Neddylation results in activation of members of the cullin-RING family of ubiquitin E3 ligases, which appear to be the major NEDD8 targets in the cell. (Adapted from PMID:25531226.)