Anti-nicastrin antibodies are used in the immunodetection of the protein encoded by the NCSTN gene. In humans, the canonical protein has a reported length of 709 amino acid residues and a mass of 78.4 kDa. Its subcellular localization is in the cytoplasmic vesicles and membrane. Alternative splicing is reported to yield 2 different isoforms for this protein. It is notably expressed in the brain. A member of the Nicastrin protein family, it is reported to be an essential subunit of the gamma-secretase complex, an endoprotease complex that catalyzes the intramembrane cleavage of integral membrane proteins such as Notch receptors and APP (amyloid-beta precursor protein). Post-translational modifications have been described, including N-glycosylation. Other names for this target antigen include ATAG1874 and anterior pharynx-defective 2.