Na+/H+ exchangers (NHEs) mediate electroneutral exchange of Na+ for H+ and thereby
play a central role in pH regulation and Na+ homeostasis. NHE3, the predominant epithelial
isoform, is found in apical membranes of renal and intestinal epithelial cells, where it
contributes to NaCl (re) absorption. NHE activity has been detected in endomembrane
vesicles of epithelial cells, but the precise compartment involved and its functional role have
not been defined. Many aspects of the targeting machinery that defines the …