Functions as a receptor for membrane-bound ligands Jagged1, Jagged2 and Delta1 to regulate cell-fate determination. Upon ligand activation through the released notch intracellular domain (NICD) it forms a transcriptional activator complex with RBPJ/RBPSUH and activates genes of the enhancer of split locus. Affects the implementation of differentiation, proliferation and apoptotic programs. Heterodimer of a C-terminal fragment N(TM) and a N- terminal fragment N(EC) which are probably linked by disulfide bonds. Interacts with MAML1, MAML2 and MAML3 which act as transcriptional coactivators for NOTCH3. Interacts with PSMA1. Interacts with HIF1AN. Ubiquitously expressed in fetal and adult tissues. Belongs to the NOTCH family. Note: This description may include information from UniProtKB.