Role of Ca²⁺/H⁺ antiporter in the kidney

Three different mechanisms for H+ transport mediated by Ca2+ have been reported. First is an ATP-dependent Ca2+/H+ antiporter which is catalyzed by (Ca2+ + Mg2+)-ATPase in plasma membrane. Second is a compensatory Ca2+ movement associated with an ATP-dependent H+ pump catalyzed by H(+)-ATPase in endosome. Third is a mitochondrial Ca2+ movement driven by an electrophoretic H+ driving force. All these processes must play a critical role on transfering messages between Ca2+ and H+. Data indicate that an ATP-dependent Ca2+ pump is an electroneutral Ca2+/H+ antiporter in renal tubular cells as well as in other nonrenal cells. The existence of this process is compatible with the physiological phenomena of Ca2+ and H+ transport in renal tubules, although we still lack direct evidence to comprehend the role of the Ca2+/H+ pump in the kidney.