Module 12: Figure amyloid cascade hypothesis
Non-amyloidogenic and amyloidogenic pathways.
The amyloid cascade hypothesis proposes that Alzheimer's disease is caused by an increase in the formation of the amyloid β peptides Aβ40 and Aβ42. In the non-amyloidogenic pathway, the amyloid precursor protein (APP) is either recycled through the endosomal pathway or is cleaved by α-secretase. During the amyloidogenic pathway, APP enters the late endosome where it is cleaved to form the amyloid β peptides (Aβ40 and Aβ42) and the APP intracellular domain (AICD). These products may act to enhance Ca2+ signalling (Module 12: Figure amyloids and Ca2+ signalling). Details of how BACE and the γ-secretase complex hydrolyse APP to form amyloid β peptides and the APP intracellular domain (AICD) is shown in Module 12: Figure APP processing.