Proton-conducting pore forming of the V0 complex of vacuolar(H+)-ATPase (V-ATPase), a multisubunit enzyme composed of a peripheral complex (V1) that hydrolyzes ATP and a membrane integral complex (V0) that translocates protons (By similarity). V-ATPase is responsible for acidifying and maintaining the pH of intracellular compartments and in some cell types, is targeted to the plasma membrane, where it is responsible for acidifying the extracellular environment (By similarity). The V-ATPase is required for the function of the excretory canal (PubMed:16785323). Involved in receptor-mediated endocytosis (PubMed:16785323). V-ATPase is a heteromultimeric enzyme made up of two complexes: the ATP-hydrolytic V1 complex and the proton translocation V0 complex (By similarity). The V1 complex consists of three catalytic AB heterodimers that form a heterohexamer, three peripheral stalks each consisting of EG heterodimers, one central rotor including subunits D and F, and the regulatory subunits C and H (By similarity). The proton translocation complex V0 consists of the proton transport subunit a, a ring of proteolipid subunits c9c'', rotary subunit d, subunits e and f, and the accessory subunits vah-19/Ac45 and vah-20/PRR (By similarity). Expressed in the H-shaped excretory cell, rectum, and a pair of cells posterior to the anus. RNAi-mediated knockdown causes embryonic lethality (PubMed:16785323). Causes defects in alae formation in the few surviving larvae and impairs yolk uptake by the oocytes from the pseudoceolomic cavities (PubMed:16785323). Causes an increase in the section of the excretory canal, which often has multiple lumens and abnormal whorls (PubMed:16785323). Belongs to the V-ATPase proteolipid subunit family.