Ubiquitin-Conjugating Enzyme E2 S (UBE2S) is a member of the Ubiquitin-Conjugating Enzyme family. UBE2S interacts with CDC20, FZR1/CDH1 and VHL. UBE2S can form a thiol ester linkage with Ubiquitin in an Ubiquitin Activating Enzyme-Dependent manner, a characteristic property of Ubiquitin Carrier Proteins. UBE2S acts as an essential factor of the Anaphase Promoting Complex/Cyclosome, a cell cycle-regulated Ubiquitin ligase that controls progression through mitosis. UBE2S is also involved in ubiquitination and subsequent degradation of VHL, resulting in an accumulation of HIF1A.