Subunit of the V1 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). Regulates pH homeostasis in the intestine (PubMed:16684534). Probably by regulating cytoplasmic pH, required for cell survival in the intestine and hypodermis (PubMed:16684534). Involved in receptor-mediated endocytosis (PubMed:12853134, PubMed:16785323). Involved in embryogenesis and larval development (PubMed:12853134, PubMed:16785323). V-ATPase is a heteromultimeric enzyme made up of two complexes: the ATP-hydrolytic V1 complex and the proton translocation V0 complex. 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. 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. Localizes in clusters in the cytoplasm of the excretory canal (PubMed:12853134). Colocalizes with vha-5 to stacked sheets of the apical cell membrane of syncytial hypodermal cells (PubMed:12853134, PubMed:16785323). Expressed in the excretory cell and syncytial hypodermal cells (at protein level) (PubMed:12853134, PubMed:16684534, PubMed:16785323). Expressed in the intestine (at protein level) (PubMed:16684534). Expressed in embryos, larvae and adults (at protein level) (PubMed:12853134, PubMed:16684534). Expressed in the excretory cell, intestine and hypodermis throughout all developmental stages and in adults (at protein level) (PubMed:12853134, PubMed:16684534). Larvae are arrested at the L1 stage (PubMed:16684534). Larvae exhibit swollen vacuoles in the hypodermis of the head region, gradually spreading throughout the whole body (PubMed:16684534). Pharyngeal pumping ceases at L2 larval stage with many vacuoles covering the entire body (PubMed:16684534). Causes necrotic cell death in intestine and hypodermis (PubMed:16684534). RNAi-mediated knockdown causes sterility, formation of endomitotic oocytes in the proximal gonads, and impaired ovulation (PubMed:12853134). Diakinesis stage oocytes are displaced toward distal gonads (PubMed:12853134). Impaired yolk uptake by the oocytes from the pseudoceolomic cavities (PubMed:12853134, PubMed:16785323). Impaired acidification and food digestion of the intestine (PubMed:16684534). Causes an increase in the section of the excretory canal, which often has multiple lumens and abnormal whorls (PubMed:16785323). Does not affect alae formation in larvae (PubMed:16785323). Progeny is arrested at the embryonic stage or at the L1 larval stage (PubMed:12853134, PubMed:16785323). RNAi-mediated knockdown in embryos causes arrest at the one-cell stage (PubMed:12853134). Belongs to the V-ATPase E subunit family.