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 (Probable). In neurons, required for necrotic cell death probably by promoting intracellular acidification (PubMed:16005300). Required for spermatogenesis where it regulates the fibrous body-membranous organelle (FBMO) morphology in spermatocytes and the acidification of FBMO-derived secretory membranous organelles (MOs) as spermatids mature (PubMed:9178007, PubMed:22446317). 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). In spermatocytes at the meiotic I stage, localizes to the cytoplasm and to discrete dots (PubMed:22446317). In spermatids and the residual body, localizes to discrete dots in the cytoplasm (PubMed:22446317). In budded spermatids, localizes near the cell membrane as discrete dots that are adjacent to secretory membranous organelles (MOs) (PubMed:22446317). Predominantly expressed in male and hermaphrodite testis (at protein level). Spermatogenesis is arrested at the primary spermatocyte stage. Belongs to the ATPase alpha/beta chains family.