PHYSIOLOGY AND BIOCHEMISTRY OF THE KIDNEY VACUOLAR H-ATPASE()

Vacuolar H+-ATPases have an essential role in renal hydrogen ion secre tion in the proximal tubule, collecting duct, and other segments of th e nephron. Control of H+ transport is achieved by variations in the in trinsic properties of the renal H+-ATPases and by several cellular reg ulatory mechanisms, including redistribution of the enzyme both by ves icular traffic and regulated assembly and disassembly, and cytosolic r egulatory proteins that interact directly with H+-ATPase. These mechan isms may provide a means for fine control of net acid excretion and fo r regulating vacuolar H+-ATPases residing on the plasma membrane indep endently from those in intracellular compartments.