Renal chloride-bicarbonate exchangers.
This review discusses the molecular identities and functional properties of sodium-independent Cl(-)-HCO3- exchangers in the kidney. The main sites of renal Cl(-)-HCO3- exchange are in the intercalated cells of the collecting duct. The function of Cl(-)-HCO3- exchange is to provide a pathway for base efflux to balance the ATP-driven H+ efflux in cells that carry out transcellular net transport of H+. In the alpha-intercalated cell, which secretes H+ into the lumen, there is now excellent evidence that the basolateral Cl(-)-HCO3- exchanger is an N-terminal truncated form of the erythrocyte anion exchanger 1 (band 3) protein. In the beta-intercalated cell, which secretes HCO3-, it is well established that there is a Cl(-)-HCO3- exchanger in the apical membrane. Functional, immunocytochemical, and biochemical evidence indicate that the apical Cl(-)-HCO3- exchanger is not a product of the anion exchanger 1 gene. The identity of this protein remains uncertain.
Godinich
M J
MJ
Department of Internal Medicine, University of Texas Medical Branch, Galveston, USA.
Jennings
M L
ML
D000818:Animals; D017920:Antiporters / Q000378:metabolism*; D001639:Bicarbonates / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D006801:Humans; D009399:Nephrons / Q000166:cytology / Q000378:metabolism*
D017920:Antiporters; D001639:Bicarbonates; D002712:Chlorides