RING finger, H2 subclass, found in ubiquitin-protein ligase E3-alpha-3 (UBR3) and similar proteins
UBR3, also known as N-recognin-3, E3alpha-III, or zinc finger protein 650, is an E3 ubiquitin-protein ligase targeting the essential DNA repair protein APE1, also known as Ref-1, for ubiquitylation. It regulates cellular levels of APE1 and is required for genome stability. It also plays a regulatory role in sensory pathways, including olfaction. Moreover, in Drosophila, UBR3 regulates apoptosis by controlling the activity of Drosophila inhibitor of apoptosis protein 1 (DIAP1), which is required to prevent caspase activation. UBR3 contains an N-terminal ubiquitin-recognin (UBR) box, a C3H2C3-type RING-H2 finger, and a C-terminal UBR-specific autoinhibitory (UAIN) domain.