AP-3 complex subunit delta-1

AP-3 complex subunit delta-1 (AP3D1) is a component of the AP-3 adaptor complex, which mediates vesicle budding from the Golgi region and facilitates trafficking to lysosomes. The complex also participates in CD8+ T-cell and NK cell degranulation and works with the BLOC-1 complex to target cargo into vesicles for neuronal delivery (UniProt: O14617).

AP3D1 is expressed across multiple tissues and is implicated in lysosomal storage and vesicular trafficking pathways. Loss-of-function mutations in AP3D1 cause Hermansky-Pudlak syndrome 10 (HPS10), a rare autosomal recessive disorder characterized by oculocutaneous albinism, bleeding defects, lysosomal storage dysfunction, and neurological complications including seizures and developmental delay (UniProt: O14617).

AP3D1 is significantly downregulated in Alzheimer's disease brain tissue. In post-mortem AD brain compared to age-matched controls, AP3D1 shows reduced abundance with a mean log2 fold-change of −1.32 (Chaparral AD proteomics). This downregulation may reflect impaired lysosomal and vesicular trafficking capacity, processes implicated in amyloid-β and tau pathology accumulation.