Notch 1, also known as TAN-1, is a transmembrane protein. Its extracellular domain contains 29 epidermal growth factor-like (EGF) repeats and 3 Lin/Notch Glp (LNR) repeats, the intracellular domain contains 5 CDC10/Ankryn repeats (ANK), 1 proline, glutamate, serine, threonine-rich (PEST) motif, and 1 regulation of amino acid metabolism 23 (RAM23) domain. Notch 1 regulates the development, differentiation, and survival of a broad spectrum of cell lineages. It is involved in myogenesis, neurogenesis, gliogenesis, and lymphocyte development, resulting in Notch 1 expression in many organs such as brain, lung, thymus, spleen, bone marrow, spinal cord, eyes, mammary gland, liver, intestine, kidney, and heart. Notch 1 ligands are Jagged 1, Jagged 2, Delta 1, and Delta 4. Upon ligand binding, the intracellular domain of Notch 1 is cleaved and translocates to the cell nucleus where it forms a transcriptional activator complex with RBP-J kappa.