a protein that interacts with the E3 ubiquitin-protein ligase WWP1 and WWP2. May be involved in the third step of ubiquitin conjugation. Relatively high levels in the brain, ovary, testis and prostate. Lower levels in the liver, thymus and leukocytes. Defects are the cause of the neurodegenerative disorders dentatorubral-pallidoluysian atrophy (DRPLA) and Haw River syndrome (HRS). Note: This description may include information from UniProtKB.