UBE2S: ProductsUbiquitin-conjugating Enzyme E2S (UBE2S), also known as E2-EPF, is a widely expressed protein with a predicted molecular weight of 26 kDa. Human UBE2S shares 92% and 93% amino acid sequence identity with mouse and rat UBE2S, respectively. UBE2S expression oscillates in a cell cycle-dependent fashion, and it influences cell cycle progression by mediating the Ubiquitin-dependent proteolysis of mitotic regulators. UBE2S interacts with APC/C, a Ubiquitin ligase (E3), to catalyze the elongation of Lys11-linked Ubiquitin chains on APC/C substrates that have been mono-ubiquitinated by UbcH10/UBE2C or UbcH5/UBE2D. UBE2S is overexpressed in multiple human cancers and targets the tumor suppressor pVHL for proteasomal degradation, which stabilizes HIF-1 alpha and promotes tumor progression.