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 (beta-amyloid precursor protein). It probably represents a stabilizing cofactor required for the assembly of the gamma-secretase complex.
Belongs to the nicastrin family.
Membrane. Melanosome. Identified by mass spectrometry in melanosome fractions from stage I to stage IV.