E3 ubiquitin-protein ligase that mediates ubiquitination of Delta receptors, which act as ligands of Notch proteins. Positively regulates the Delta-mediated Notch signaling by ubiquitinating the intracellular domain of Delta, leading to endocytosis of Delta receptors. Probably mediates ubiquitination and subsequent proteasomal degradation of DAPK1, thereby antagonizing anti-apoptotic effects of DAPK1 to promote TNF- induced apoptosis. Mediates 'Lys-63'-linked polyubiquitination of TBK1, which probably participates in kinase activation. Widely expressed at low level. Expressed at higher level in spinal cord, ovary, whole brain, and all specific brain regions examined. Note: This description may include information from UniProtKB.