Lipid transfer protein required for autophagosome completion and peroxisome degradation (PubMed:8224160, PubMed:10029994, PubMed:11382760, PubMed:11382761, PubMed:11675007, PubMed:18586673, PubMed:18625846, PubMed:19371383, PubMed:19995911, PubMed:22728243, PubMed:23230146). Tethers the edge of the isolation membrane (IM) to the endoplasmic reticulum (ER) and mediates direct lipid transfer from ER to IM for IM expansion (PubMed:28704456, PubMed:29848619, PubMed:30254161). ATG2 binds to the ER exit site (ERES), which is the membrane source for autophagosome formation, using basic residues in its N-terminal region (NR) and to the expanding edge of the IM through its C-terminal region (PubMed:30254161). The latter binding is assisted by an ATG18-PtdIns3P interaction (PubMed:30254161). ATG2 then extracts phospholipids from the membrane source using its NR and transfers them to ATG9 to the IM through its predicted beta-sheet-rich structure for membrane expansion (PubMed:30254161). ATG2 is also involved in the recruitment of lipids to a restricted region close to the vacuole, termed the vacuole-isolation membrane contact site (VICS), which is also essential for autophagosome formation (PubMed:28704456). Necessary for the localization of ATG18 to the preautophagosomal structure (PAS) and the binding of ATG18 to ATG9 (PubMed:14723849, PubMed:18586673, PubMed:18625846, PubMed:19371383, PubMed:23230146). ATG2 is the most downstream ATG protein in the preautophagosomal structure organization process (PubMed:17295840). Involved in correct ATG9 trafficking through the preautophagosomal structure and in peroxisome degradation (PubMed:14723849). Plays a significant role in life span extension (PubMed:23337777). a 1,2-diacyl-sn-glycero-3-phosphocholine(in) = a 1,2-diacyl-sn-glycero-3-phosphocholine(out) a 1,2-diacyl-sn-glycero-3-phospho-L-serine(in) = a 1,2-diacyl-sn-glycero-3-phospho-L-serine(out) a 1,2-diacyl-sn-glycero-3-phosphoethanolamine(in) = a 1,2-diacyl-sn-glycero-3-phosphoethanolamine(out) Interacts with ATG18 (PubMed:17295840, PubMed:18586673, PubMed:22851171, PubMed:23230146, PubMed:30254161). Interacts with ATG9 (PubMed:29848619). Localizes to the IM-ERES contact site. The N-terminal region (NR) associates with the endoplasmic reticulum (ER) and is responsible for the formation of the isolation membrane at the PAS. The amphipathic helix in the C-terminal region binds to membranes and facilitates ATG18 binding to PtdIns3P to target the ATG2-ATG18 complex to the PAS. Impairs the formation of autophagosomes (PubMed:28704456). Completely blocks the movement of the ER-staining dye R18 from the ER to IM precursors (PubMed:28704456). Present with 876 molecules/cell in log phase SD medium. Belongs to the ATG2 family.