Aβ can trigger AD.

Abstract

(A) Proteolytic processing of APP by β-secretase and γ-secretase leads to the generation of Aβ protein. Red asterisks: mutations that cause familial AD; green asterisk: a protective mutation. Insert: typical amyloid plaques and neurofibrillary tangles of AD pathology. (B) One way to depict the amyloid cascade. Individual steps in the cascade may evoke distinct microglial responses. Aβ, amyloid β-protein; AD, Alzheimer disease; APP, amyloid precursor protein.</p