Probable subunit of the gamma-secretase complex, an endoprotease complex that catalyzes the intramembrane cleavage of integral proteins such as Notch receptors and APP (amyloid-beta precursor protein). It probably represents a stabilizing cofactor for the presenilin homodimer that promotes the formation of a stable complex. Probably present in a minority of gamma-secretase complexes compared to APH1A.
Subcellular locations: Membrane
Weakly or not expressed in leukocytes, lung, placenta, small intestine, liver, kidney, spleen thymus, colon, skeletal muscle, heart and brain.