V-ATPase is present in every known eukaryotic cell and plays a vital role. The study on the structure, function, assembly and the regulation of V-ATPase has achieved much progress recently. All the core subunits of V-ATPase have now been sequenced and most of their functions have been assigned to some extent. Membrane biochemistry and molecular biology studies discovered that the gene expression and the activity of V-ATPase are regulated in various ways.