FUNCTION: Plays a role in autophagy. SUBCELLULAR LOCATION: Membrane; multi-pass membrane protein (Potential). ALTERNATIVE PRODUCTS: 3 named isoforms produced by alternative splicing. SIMILARITY: Belongs to the ATG9 family. IN YEAST: FUNCTION: Involved in autophagy and cytoplasm to vacuole transport (Cvt) vesicle formation. Recruites ATG23 and ATG8 to the pre-autophagosomal structure. SUBUNIT: Interacts with ATG18, ATG2 and ATG23. SUBCELLULAR LOCATION: Membrane; multi-pass membrane protein. Preautophagosomal structure; preautophagosomal structure membrane; multi-pass membrane protein. Note=Pre-autophagosomal and other perivacuolar punctate structures. The proper trafficking of ATG9 between the pre-autophagosomal structure and the other punctate structures requires ATG2, ATG18, ATG23, the ATG1-ATG13 complex and the phosphatidylinositol 3-kinase complex I. SIMILARITY: Belongs to the ATG9 family.