V-type proton ATPase subunit E 2 is a protein in humans that is encoded by ATP6V1E2 gene. Subunit of the peripheral V1 complex of vacuolar ATPase essential for assembly or catalytic function. V-ATPase is responsible for acidifying a variety of intracellular compartments in eukaryotic cells. This isoform is essential for energy coupling involved in acidification of acrosome (By similarity).