[^1]
Gene
[^2]
[VPS16](/genes/vps16)
[^3]
UniProt
[Q9Y2G5](https://www.uniprot.org/uniprot/Q9Y2G5)
Subcellular Localization
Endosomal membrane, Lysosomal membrane
Protein Family
HOPS/VPS Core complex
VPS16 (Vacuolar Protein Sorting 16 homolog) is a core component of the HOPS (Homotypic fusion and Protein Sorting) complex, which is essential for late endosomal and lysosomal trafficking. The HOPS complex mediates fusion of late endosomes with lysosomes, a critical step in autophagy and cellular waste clearance.
VPS16 is a ~790 amino acid protein that serves as a scaffolding subunit within the hexameric HOPS complex. It interacts directly with VPS33, VPS16, VPS18, and other HOPS subunits to form the stable core complex. The protein contains multiple alpha-helical domains that facilitate protein-protein interactions.
In neurons, VPS16 and the HOPS complex play essential roles in:
- Autophagosome-lysosome fusion: The HOPS complex facilitates the final fusion step of autophagy, clearing misfolded proteins and damaged organelles
- Lysosomal trafficking: Essential for proper lysosomal enzyme delivery and function
- Synaptic vesicle recycling: Involved in endosomal sorting at synaptic terminals
- Neuronal homeostasis: Maintains cellular waste clearance mechanisms critical for neuronal survival
Dysfunction of VPS16 and the HOPS complex has been implicated in several neurodegenerative diseases:
- Impairment of autophagic-lysosomal pathway leads to accumulation of alpha-synuclein aggregates
- VPS16 dysfunction may contribute to impaired mitophagy in PD
- Disrupted lysosomal function contributes to amyloid-beta accumulation
- HOPS complex abnormalities affect APP processing and Aβ clearance
- HOPS complex mutations cause trafficking defects in lysosomal enzymes
- Contributes to neuropathology in diseases like Niemann-Pick type C
The HOPS complex represents a potential therapeutic target for neurodegenerative diseases:
- Autophagy enhancement: Small molecules that enhance HOPS function may improve clearance of protein aggregates
- Lysosomal function modulators: Compounds that boost lysosomal activity could compensate for HOPS deficits
- Gene therapy approaches: VPS16 gene delivery to restore proper trafficking