Roles of V-ATPases in cell physiology. V-ATPases have vital roles in the Golgi apparatus. Mutations in the a2-subunit, which is found in the Golgi, result in a form of cutis laxa due to impaired glycosylation. In secretory pathways, energy from a proton gradient generated by V-ATPases may be used to load molecules like glutamate. V-ATPases in endosomal compartments are involved in disassociating complexes, like the mannose-6 phosphate receptor from cathepsins. Acid-dependent enzymes may also become active due to V-ATPase acidification to modify proteins in the lumen of the vesicles. There is also increasing evidence that the V-ATPase may be able to recruit regulators of vesicular trafficking like ARF6. V-ATPases in the lysosome provide an acidic environment for the degradation of proteins by acidic proteases.