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 (PubMed:2141385). V-ATPase is responsible for acidifying and maintaining the pH of intracellular compartments (PubMed:2141385). V-ATPase is a heteromultimeric enzyme composed of a peripheral catalytic V1 complex (components A to H) attached to an integral membrane V0 proton pore complex (components: a, c, c', c'', d, e, f and VOA1) (PubMed:25971514, PubMed:18055462, PubMed:27295975). Interacts with RAV1 and RAV2 components of the RAVE complex, which are essential for the stability and assembly of V-ATPase (PubMed:11283612). Present with 131000 molecules/cell in log phase SD medium. Belongs to the ATPase alpha/beta chains family. PubMed:1371275 sequence was incorrectly thought to originate from bovine.