Nicastrin and presenilin are two major components of the gamma-secretase complex, which executes the intramembrane proteolysis of type I integral membrane proteins such as the amyloid precursor protein (APP) and Notch. Nicastrin is synthesized in fibroblasts and neurons as an endoglycosidase-H-sensitive glycosylated precursor protein (immature nicastrin) and is then modified by complex glycosylation in the Golgi apparatus and by sialylation in the trans-Golgi network (mature nicastrin). A region featured in this family has a fold similar to human transferrin receptor (TfR) and a bacterial aminopeptidase. It is implicated in the pathogenesis of Alzheimer's disease.
Jiyao W et al.(2023). "The conserved domain database in 2023.",