Subunit of the V0 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. 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). May play a role in coupling of proton transport and ATP hydrolysis (By similarity). Regulator of osteoclast fusion and bone formation (By similarity). . This is the function of ATP6V0D2 (ATPase H+ transporting V0 subunit d2, ENSG00000147614).