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， or E1s， ubiquitin-conjugating enzymes， or E2s， and ubiquitin-protein ligases， or E3s. This gene encodes a member of the E1 ubiquitin-activating enzyme family. The encoded enzyme associates with AppBp1， an amyloid beta precursor protein binding protein， to form a heterodimer， and then the enzyme complex activates NEDD8， a ubiquitin-like protein， which regulates cell division， signaling and embryogenesis. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene.