Work

Substrate docking to γ-secretase allows access of γ-secretase modulators to an allosteric site

Year: 2010

Type: article

Abstract: γ-Secretase generates the peptides of Alzheimer's disease, Aβ40 and Aβ42, by cleaving the amyloid precursor protein within its transmembrane domain. γ-Secretase also cleaves numerous other substrates, raising concerns about γ-secretase inhibitor off-target effects. Another important class of drugs, γ-secretase modulators, alter the cleavage site of γ-secretase on amyloid precursor protein, changing the Aβ42/Aβ40 ratio, and are thus a promising therapeutic approach for Alzheimer's disease. However, the target for γ-secretase modulators is uncertain, with some data suggesting that they function on γ-secretase, whereas others support their binding to the amyloid precursor. In this paper we address this controversy by using a fluorescence resonance energy transfer-based assay to examine whether γ-secretase modulators alter Presenilin-1/γ-secretase conformation in intact cells in the absence of its natural substrates such as amyloid precursor protein and Notch. We report that the γ-secretase allosteric site is located within the γ-secretase complex, but substrate docking is needed for γ-secretase modulators to access this site. γ-Secretase modulators have promise in the treatment of Alzheimer's disease, but their molecular target is uncertain. Here, fluorescence resonance energy transfer is used to determine that the γ-secretase allosteric site is within the γ-secretase complex and that substrate docking is required for modulators to access the site.

Source: Nature Communications

DOI: 10.1038/ncomms1129