Notch proteins (Notch1-4) are a family of transmembrane receptors that play important roles in development and the determination of cell fate. The notch genes are expressed in a variety of tissues in both the embryonic and adult organism, suggesting that the genes are involved in multiple signaling pathways. The notch proteins have been found to be overexpressed or rearranged in human tumors. Ligands for notch include Jagged1, Jagged2 and Delta. Jagged can activate notch and prevent myoblast differentiation by inhibiting the expression of muscle regulatory and structural genes. Delta expression has also been found in neuroendocrine tumors such as neuroblastomas and pheochromocytomas.
