UBE2F accepts the ubiquitin-like protein NEDD8 from the NEDD8^E1 complex and catalyzes its covalent attachment to other proteins. The specific interaction with the E3 ubiquitin ligase RBX2, but not RBX1, suggests that the RBX2-UBE2F complex modifies specific target proteins, such as CUL5. UbcH12 (UBE2M) is another NEDD8 E2 conjugating enzyme with interacts with RBX1 and targets different types of cullin substrates. The UBE2F and UBE2M enzymes thus represent a hierarchical expansion of the NEDD8 conjugation system in establishing selective culling RING ligase activation which influences substrate sub-type NEDDylation. This protein has an N-terminal His6-tag. Accession # NP_542409.