UBE2D4 is a member of the ubiquitin-conjugating enzyme family. Ubiquitin-conjugating enzymes（E2 enzymes or ubiquitin-carrier enzymes) execute the second step in the ubiquitination reaction which marks a protein for degradation using the proteasome. UBE2D4 receives ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro UBE2D4 can promote polyubiquitination using all 7 ubiquitin Lys residues， but usually selects ’Lys-11’ and ’Lys-48’-linked polyubiquitination.
