Accepts the ubiquitin-like protein Nedd8 from the Uba3-APP-BP1 E1 complex and catalyzes its covalent attachment to other proteins. Required for Cul1 and Cul3 neddylation. Negatively regulates full-length ci stability and hedgehog signaling. [E1 NEDD8-activating enzyme]-S-[NEDD8 protein]-yl-L-cysteine + [E2 NEDD8-conjugating enzyme]-L-cysteine = [E1 NEDD8-activating enzyme]-L-cysteine + [E2 NEDD8-conjugating enzyme]-S-[NEDD8-protein]-yl-L-cysteine. Protein modification; protein neddylation. Interacts with Uba3. Expressed in the wing disk. Both the N-terminal docking peptide and the catalytic core domain must bind the Uba3-Ula1 complex simultaneously for optimal transfer of Nedd8. Belongs to the ubiquitin-conjugating enzyme family. UBC12 subfamily.