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). Plays an important role in resistance to several stresses, as well as in autophagy and virulence (PubMed:25038082). 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). Results in the inability to grow at alcaline pH and altered resistance to calcium, osmotic stress, cold temperature, antifungal drugs and growth on non-fermentable carbon sources. Leads also to unability to fully assemble the V-ATPase at the vacuolar membrane and impairs its proton transport and ATPase activities. Finally, leads to autophagy defect and avirulence in a Caenorhabditis elegans infection model. Belongs to the ATPase alpha/beta chains family.