Downstream effector of Notch signaling. Involved in the regulation of liver cancer cells self-renewal (By similarity). Involved in the regulation of canonical Wnt signaling by stabilizing LEF1 (By similarity). Involved in angiogenesis acting downstream of Notch at branch points to regulate vascular density. Proposed to integrate endothelial Notch and Wnt signaling to control stalk cell proliferation and to stablilize new endothelial connections during angiogenesis (PubMed:19154719). During somitogenesis involved in maintenance of proper somite segmentation and proper numbers of somites and vertebrae. Required for proper anterior-posterior somite patterning. Proposed to function in a negative feedback loop to destabilize Notch 1 intracellular domain (NICD) and down-regulate the Notch signal, preventing expansion of the Notch signal into the anterior somite domain (PubMed:21795391, PubMed:21998026). Interacts with LEF1. Expressed at high levels in the brain, heart, colon, kidney, liver, lung and small intestine. Expressed in retina, most prominent in endothelial cells at the migrating point of the vasculature behind leading tip cells. Expressed in testis. During embryogenesis, expressed in several tissues in which cellular differentiation is regulated by the notch signaling pathway. At 10.5 dpc expressed in intersomatic vessels and in vessels of the limb buds with strongest expression at vascular branch points. Cyclic expression between 8.5 dpc and 10.5 dpc somitogenesis is dependent on DLL3. By Notch signaling via a CBF1/Su(H)/Lag-1 (CSL)-dependent pathway. Axial skeletal defects in newborn mice such as rib fusions, fused vertebral bodies and fused pedicles of the vertebrae; defects are influenced by the strain-specific genetic background. Embryos exhibit expansion and fusion of myotomes, dorsal root ganglia fusions and defects in projection of the spinal nerves. Embryos show increased level of Notch 1 intracellular domain (NICD) expression in presomitic mesoderm and somites (PubMed:21998026). In contrast, fewer somites and vertebrae found in -/- are linked to a longer segmentation clock period (PubMed:21795391). Defects in the radial expansion of the vascular plexus from the optic nerve head to the periphery, reduction of retinal vessel density; however, most of the defects in angiogenesis resolve over time (PubMed:19154719). Belongs to the NRARP family.