The protein encoded by this gene belongs to the ubiquitin-conjugating enzyme family. This protein interacts with RING finger proteins, and it can ubiquitinate huntingtin, the gene product for Huntington's disease. Known functions for this protein include a role in aggregate formation of expanded polyglutamine proteins and the suppression of apoptosis in polyglutamine diseases, a role in the dislocation of newly synthesized MHC class I heavy chains from the endoplasmic reticulum, and involvement in foam cell formation. Multiple transcript variants encoding different isoforms have been identified for this gene. [provided by RefSeq, Jul 2008].