Ube2D3 is an E2 enzyme, which is part of the E1, E2, and E3 cascade responsible for ubiquitination of protein substrates.Ube2D3 is 88% identical to the amino acid sequence of Ube2D1.Ube2D3 works with Mdm2 (an E3 ligase) to ubiquitinate and regulate protein levels of p53 and Mdm2. Ube2D3 has been linked to cadminum toxicity.It might also play a role in LDL cholesterol receptor ubiquitination in an Idol-dependent fashion.