This gene encodes an E3 ubiquitin-protein ligase required for the maintenance of the antephase checkpoint that regulates cell cycle entry into mitosis and, therefore, may play a key role in cell cycle progression and tumorigenesis. The encoded protein has an N-terminal forkhead-associated domain, a central RING-finger domain, and a cysteine-rich C-terminal region. Alternatively spliced transcript variants that encode different protein isoforms have been described.