Non-catalytic 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). Essential for the proper assembly and activity of V-ATPase (By similarity). Required maternally for early embryogenesis and zygotically during morphogenesis. Specifically, involved in the clearance of apoptotic cell corpses in embryos. Also, during embryonic development, the V-ATPase is required to repress fusion of epidermal cells probably by negatively regulating eff-1-mediated cell fusion. In neurons, required for necrotic cell death by promoting intracellular acidification. Required for cell death induced by hypoxia. Required for acidification of synaptic vesicles and the release of neurotransmitters from adult neurons (By similarity). 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. Belongs to the ATPase alpha/beta chains family.