Figure 4. Aβ in endocytic vesicles, autophagic vacuoles, lysosomes and mitochondria.

Co-localization of Aβ (4G8) in neurons in the frontal cortex of a 10-year-old subject diagnosed with autism/dup(15) (AN06365) demonstrates that a small portion of cytoplasmic Aβ is stored in rab5-positive endocytic vesicles and LC3B-positive autophagic vacuoles, whereas the largest proportion of Aβ is colocalized with lysosomal Lamp1. Colocalization of a relatively large portion of cytoplasmic Aβ with lysosomal markers appears to reflect the accumulation of products of intracellular degradation of Aβ that originated from endocytic and autophagic pathways. The presence of only a few Aβ-positive mitochondria immunolabeled with COXIV may suggest that this Aβ makes the smallest contribution to the detected neuronal Aβ accumulation and degradation pathway.