Neurogenic locus notch homolog 4 (Notch 4) is a protein that in humans is encoded by the NOTCH4 gene located on chromosome 6. Notch protein family members play a role in a variety of developmental processes by controlling cell fate decisions. The Notch signaling pathway is an evolutionarily conserved intercellular signaling pathway that regulates interactions between physically adjacent cells. In Drosophila, notch interacts with its cell-bound ligands (delta and serrate), and establishes an intercellular signaling pathway that then plays a key role in development. Homologues of the notch-ligands have also been identified in humans, but precise interactions between these ligands and the human notch homologues remain to be determined. The notch protein is cleaved in the trans-Golgi network, and then presented on the cell surface as a heterodimer. The protein functions as a receptor for membrane bound ligands, and may play a role in vascular, renal, and hepatic development.