UEV3, also known as EV and lactate/malate dehydrogenase domain-containing protein, is a 471 amino acid protein that contains one UEV (ubiquitin E2 variant) domain, which typically interacts with ubiquitin. UEV3 is thought to be a paralogue of tsg 101, a protein that exerts regulatory effects on E2 activity in cellular ubiquitination processes. With amino-terminal homology to the catalytic domain of ubiquitin-conjugating enzymes, it is thought that UEV3 may function as a negative regulator of polyubiquitination. UEV3 is expressed in various colon carcinoma cell lines, carcinomas of the uterine cervix and peripheral blood leukocytes as well as normal colon and cervical epithelium.