The PI(3,5)P2 regulatory complex regulates both the synthesis and turnover of phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2). May negatively regulate FAB1 activity by sequestering or masking VAC7 from FAB1. Necessary for proper vacuole morphology. Plays an important role in osmotically-induced vacuole fragmentation. Required for cytoplasm to vacuole transport (Cvt) vesicle formation, pexophagy and starvation-induced autophagy. Involved in correct ATG9 trafficking to the pre-autophagosomal structure. Might also be involved in premeiotic DNA replication. With ATG2, protects ATG8 from ARG4-mediated cleavage (By similarity). Component of the PI(3,5)P2 regulatory complex, composed of ATG18, FIG4, FAB1, VAC14 and VAC7 (By similarity). VAC14 nucleates the assembly of the complex and serves as a scaffold (By similarity). Interacts with ATG2, ATG9 and VAC17. The ATG2-ATG18 complex is essential for autophagosome formation (By similarity). Requires VAC7 for vacuole membrane localization. Under mid-log phase growth, localizes to the vacuolar membrane; but when cells are starved, is almost completely released from the vacuole membrane (By similarity). The 377 first amino acids might form a beta-propeller domain involved in specific binding to phosphatidylinositol 3,5-bisphosphate (PIP2), leading to the association of the protein to the membrane. Association to the membrane can also occur through binding to phosphatidylinositol 3-monophosphate (PI3P). The L/FRRG motif is essential for the cytoplasm to vacuole transport (Cvt) pathway, for the recruitment of ATG8 and ATG16 to the PAS in nutrient-rich medium, and for its recruitment to and dissociation from the PAS under starvation conditions. Belongs to the WD repeat PROPPIN family.