AP-3 complex subunit mu-1

AP-3 complex subunit mu-1 (AP3M1) is a component of the AP-3 adaptor complex, which mediates vesicle budding from the Golgi membrane and trafficking to lysosomes (UniProt: Q9Y2T2). In neurons, the AP-3 complex works with BLOC-1 to direct cargo into vesicles at cell bodies for delivery to neurites and nerve terminals, linking it to synaptic function and neuronal trafficking pathways.

AP3M1 is downregulated in Alzheimer's disease brain tissue relative to age-matched controls, with a mean log2 fold-change of −0.97 across subcellular fractions in post-mortem TMT proteomics (Chaparral AD proteomics). This reduction may impair vesicle trafficking and lysosomal delivery, processes increasingly recognized as disrupted in AD pathology. The direction tag indicates consistent downregulation in the analyzed brain fractions (down). No SFARI curation is available for this protein.