May play a role in the establishment and maintenance of neuronal transmission and plasticity via its ubiquitin ligase activity. E3 ubiquitin ligases accept ubiquitin from an E2 ubiquitin-conjugating enzyme in the form of a thioester and then directly transfer the ubiquitin to targeted substrates. S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Interacts with UBE2N. Expressed primarily in the nervous system. Expression is more intense in the granular cell layer of hippocampus, Purkinje cell layer of the cerebellum and the granular cell layer of the olfactory bulb. Detected in sensory neurons but not expressed in sympatic or enteric neurons. Expressed in testis, adipose tissue, columnar epithelial cells of the gut. The RING-type zinc finger domain is required for E3 ligase activity.