ATG9 Antibody

ATG9 Antibody: Definition and Function

ATG9A is the sole transmembrane protein in the core autophagy machinery, required for autophagosome biogenesis and lipid homeostasis . ATG9 antibodies are designed to bind specifically to ATG9A, facilitating its detection and isolation in experimental systems. These antibodies are validated for use in:

• Western blotting: To quantify ATG9A protein levels.

• Immunoprecipitation: To isolate ATG9A-associated complexes.

• Immunofluorescence: To visualize ATG9A localization in cells.

• Immunoisolation: To purify ATG9A-containing vesicles for proteomic analysis .

Key Applications of ATG9 Antibodies

Validation of ATG9 Antibodies

ATG9 antibodies undergo rigorous validation to ensure specificity and reproducibility. Key validation strategies include:

Western Blot Validation

• Positive Controls: Rat brain lysates or HEK293 cells overexpressing ATG9A .

• Negative Controls: ATG9A knockout (KO) cells .

• Observed Bands:

  • Abcam ab108338: 50–70 kDa, 53 kDa, 72 kDa .

  • GeneTex GTX128427: ~53 kDa (full-length ATG9A) .

• KO Testing: Loss of signal in ATG9A KO lysates confirms specificity .

Immunoprecipitation

• IP Efficiency: ATG9A is enriched in eluted fractions vs. non-bound fractions .

• Proteomic Analysis: Co-precipitated proteins (e.g., Arfaptins, phosphoinositide kinases) validate ATG9A’s functional interactions .

Immunofluorescence

• Localization: ATG9A colocalizes with Golgi/ER markers (e.g., TOM20) under basal conditions and shifts to autophagosome precursors during starvation .

Autophagosome Formation

ATG9A is essential for autophagosome biogenesis, acting as a seed membrane source . Key studies include:

• ATG9A KO Cells: Fail to form LC3B-positive autophagosomes, leading to p62 accumulation .

• Membrane Contribution: ATG9A vesicles (~30–50 nm) deliver lipids to phagophores, enabling expansion .

Lipid Mobilization and Metabolism

ATG9A regulates lipid droplet (LD) homeostasis and fatty acid oxidation:

• LD Dynamics: ATG9A depletion increases LD size and number, impairing fatty acid transfer to mitochondria .

• Scramblase Activity: ATG9A flips phospholipids between membrane leaflets, facilitating membrane remodeling .

Chemotaxis and Cell Migration

ATG9A modulates chemotactic migration in glioma and epithelial cells:

• Mechanism: ATG9A interacts with Arfaptin 2 to shape autophagosomes and regulate cytoskeletal dynamics .

• Phenotype: ATG9A knockdown reduces migratory speed and persistence .

Antiviral Defense

ATG9A associates with DC-SIGN (a C-type lectin receptor) to limit HIV-1 transmission:

• Nanoclusters: STED microscopy reveals DC-SIGN-ATG9 nanoclusters that degrade viral particles .

• Functional Impact: ATG9A depletion increases HIV-1 transfer to CD4+ T cells .