Synonyms:HHR6A, HR6A, RAD6 homolog A, RAD6A, UBC2, UBE2A, Ubiquitin carrier protein A, Ubiquitin protein ligase A Background:The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation. Ubiquitination involves at least three classes of enzymes: ubiquitin-activating enzymes, ubiquitin-conjugating enzymes, and ubiquitin-protein ligases. This gene encodes a member of the E2 ubiquitin-conjugating enzyme family. This enzyme is required for post-replicative DNA damage repair, and may play a role in transcriptional regulation. Mutations in this gene are associated with mental retardation. Alternative splicing results in multiple transcript variants.