A.
Notch is a crucially important receptor in all animals, both during development and in adults. Among other things, it controls the development of neural cells in Drosophila.
B.
In this simple signaling pathway, the receptor itself acts as a transcription regulator.
C.
When activated by the binding of Delta, a transmembrane signal protein on the surface of a neighboring cell, the Notch receptor is cleaved.
D.
This cleavage releases the cytosolic tail of the receptor, which is then free to move to the nucleus, where it helps to activate the appropriate set of Notch-responsive genes.