Notch signaling pathway

The Notch signaling pathway is a widespread and highly conserved signal transduction pathway can respond through the cells to external signals. The signal path is named after its receptor " Notch " which binds the membrane-bound ligand "Delta" on the surface of another cell. Notch is a transmembrane protein with a single transmembrane domain and a large extracellular domain.

Operation

The Notch signaling pathway is based on the proteolysis and is activated by the binding of the ligand to the receptor Notch Delta. The Notch receptor is proteolytically cut three times, after Delta has bound the first time in the Golgi apparatus and then two more times. First extracellular domain is cleaved close to the plasma membrane. Then, the cytoplasmic portion of membrane-bound Notch receptor by another enzyme (presumably presenilin -1) is separated off and is now free to diffuse into the nucleus, where the fragment in a complex, together with other regulatory proteins to the CSL protein - as named as a combination of CBF -1 in mammals, suppressor of Hairless ( Drosophila melanogaster ) in the fruit fly and lag -1 in the nematode worm ( Caenorhabditis elegans) - binds and regulates the expression of Notch -response genes.

Occurrence

The Notch signaling pathway is involved in the development of most tissues in the animal embryo, it is particularly well studied in nerve cells. Delta - Notch interactions mediate lateral inhibition, in which each cell integrates information of its surrounding cells for their own destiny. In other cells, Notch may also contribute to the development of synchronization operations.

Discovery

The gene for the Notch receptor was discovered in 1917 by Thomas Hunt Morgan, who described a mutation in the fruit fly Drosophila melanogaster, which had notches ( eng. notches) on their wings.