Structure and Properties of the Vacuolar (H+)-ATPases

The vacuolar (H+)-ATPases (or V-ATPases) are a family of ATP-dependent proton pumps that are responsible for acidification of intracellular compartments in eukaryotic cells (1-3). Acidification of vacuolar compartments plays an important role in a variety of cellular processes, particularly membrane traffic processes. In receptor-mediated endocytosis, acidification of endosomes serves as a signal that activates release of internalized ligands (such as low density lipoprotein and insulin) from their receptors.