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| ATG9B Protein |
|---|
| Protein Name | Autophagy-related protein 9B |
| Gene | [ATG9B](/genes/atg9b) |
| UniProt ID | [Q9H0Y7](https://www.uniprot.org/uniprot/Q9H0Y7) |
| PDB Structure | Not determined |
| Molecular Weight | ~102 kDa |
| Subcellular Localization | Trans-Golgi network, endosomes, autophagosomes |
| Protein Family | ATG9 family |
ATG9B Protein is a protein encoded by the ATG9B gene. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
ATG9B is a multi-pass transmembrane protein unique among ATG proteins:
- Six transmembrane domains: Form a pore-like structure in membranes
- N-terminal cytosolic domain: Contains sorting motifs and phosphorylation sites
- C-terminal cytosolic domain: Contains trafficking signals
- Lumenal loop regions: Predicted to face the interior of organelles
The transmembrane domains allow ATG9B to span various organelle membranes, positioning it uniquely in the autophagy pathway.
ATG9B performs essential functions in neuronal autophagy:
- Autophagy initiation: One of the first autophagy proteins recruited to the phagophore
- Membrane recruitment: Supplies membranes from the trans-Golgi network and endosomes
- Phagophore expansion: Acts as a scaffold for other ATG proteins
- Neuronal survival: Maintains protein quality control critical for long-lived neurons
- Synaptic function: Involved in autophagy-dependent synaptic protein turnover
In the nervous system, ATG9B is particularly important in presynaptic terminals where local autophagy regulates synaptic vesicle recycling and neurotransmitter release.
ATG9B dysfunction contributes to neurodegenerative processes:
- Altered ATG9B trafficking observed in AD neuronal models
- Impaired autophagic membrane supply contributes to amyloid-beta accumulation
- ATG9B dysfunction exacerbates tau pathology through defective autophagy
- ATG9B is critical for mitophagy, and its dysfunction affects mitochondrial quality control
- Alpha-synuclein aggregation disrupts ATG9B-dependent autophagy
- Studies link ATG9B variants to PD susceptibility
- ATG9B mislocalization is observed in ALS motor neurons
- Disrupted membrane trafficking contributes to protein aggregate accumulation
- Autophagy defects in ALS involve ATG9B dysfunction
- ATG9B mutations identified in patients with complex hereditary spastic paraplegia
- Impaired axonal autophagy leads to progressive neurodegeneration
Therapeutic strategies targeting ATG9B:
- Gene therapy: AAV-based delivery of functional ATG9B in development
- Small molecule modulators: Autophagy-enhancing compounds indirectly boost ATG9B function
- Protein stabilization: Small molecules to stabilize ATG9B structure
- Biomarker development: ATG9B levels as a biomarker for autophagy function
Categories: Proteins | Autophagy Proteins | Neurodegeneration