Neurogenic locus notch homolog protein 4 (Notch 4) is a transmembrane heterodimer in which the extracellular domain contains 29 EGF repeats and 3 LNR repeats. The intracellular domain contains 5 ANK repeats, 1 PEST motif, and 1 RAM23 domain. Notch 4 controls many developmental processes in the cell such as differentiation, proliferation, and apoptosis. In addition, it also plays a role in vascular, renal, and hepatic development. Notch 4 is expressed by a variety of tissues such as heart, lung, placenta, liver, skeletal muscle, kidney, pancreas, spleen, lymph node, thymus, bone marrow, and fetal liver. The Notch 4 ligands are Jagged1, Jagged2, Delta1, Delta3 and Delta4. After ligand binding, Notch 4 is cleaved by the TNF-alpha converting enzyme (TACE). The extracellular domain remains on the cell surface while the intracellular domain is released and translocated to the nucleus where it binds to CBF-1, leading to the expression of genes of the Hairy/Enhancer of Split (HES) and HES-related repressor protein (HERP) families.