Structural conservation of Notch receptors and ligands

The Notch signalling pathway is an evolutionary conserved cell-to-cell comm unication system utilized multiple times and in many tissues during develop ment. The outcome of an interaction between Notch and its ligands is highly influenced by factors both extrinsic and intrinsic to Notch expressing cel ls, suggesting that Notch functions either directly or in parallel with oth er signalling systems to regulate cellular differentiation events. Protein domains common to all ligands and receptors of this system suggest conserve d functional properties that likely relate to regulatory mechanisms for Not ch signalling. Within this review, the known functional properties of these domains are analyzed with respect to their contributions to ligand/recepto r interactions and Notch signalling.