The study investigates the release of β-amyloid (Aβ) peptides from cells and their association with exosomes. Aβ peptides are formed by the amyloidogenic cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. The research shows that β-cleavage occurs in early endosomes, followed by the routing of Aβ to multivesicular bodies (MVBs). A small fraction of Aβ peptides is then secreted from the cells in association with exosomes, which are intraluminal vesicles of MVBs that fuse with the plasma membrane. Exosomal proteins, such as Alix, were found to accumulate in the plaques of Alzheimer's disease (AD) patient brains, suggesting a role in AD pathogenesis. The study also demonstrates that Aβ peptides are localized to MVBs and can be released as exosomes, providing a potential mechanism for their extracellular release.The study investigates the release of β-amyloid (Aβ) peptides from cells and their association with exosomes. Aβ peptides are formed by the amyloidogenic cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. The research shows that β-cleavage occurs in early endosomes, followed by the routing of Aβ to multivesicular bodies (MVBs). A small fraction of Aβ peptides is then secreted from the cells in association with exosomes, which are intraluminal vesicles of MVBs that fuse with the plasma membrane. Exosomal proteins, such as Alix, were found to accumulate in the plaques of Alzheimer's disease (AD) patient brains, suggesting a role in AD pathogenesis. The study also demonstrates that Aβ peptides are localized to MVBs and can be released as exosomes, providing a potential mechanism for their extracellular release.