Fig. 5.

Proposed model of GSAP modulation of γ-secretase activity. (A and B) γ-Secretase complex presented as transmembrane rods containing PS1-NTF (green), PS1-CTF (red), Nct (purple), Aph1 (blue), and Pen2 (orange) in the presence (A) of GSAP (blue sphere) in WT or in GSAP rescue with induced PS1 conformation, which leads to γ-secretase activity for both APP and Notch. When GSAP is absent (B) PS1 adopts a different conformation, which leads to a decrease in APP processing and a reduction in Aβ secretion, but not in Notch processing.