The apical Cl/HCO3 exchanger of beta intercalated cells.
There are two types of intercalated cells of the renal collecting duct; one secretes H+ and the other secretes HCO3-. The H(+)-secreting form has an apical vacuolar H(+)-ATPase and a basolateral Cl/HCO3 exchanger that cross-reacts with antibodies to band 3, the product of the AE1 gene. The HCO3(-)-secreting form has a basolateral vacuolar H(+)-ATPase and an apical Cl/HCO3 exchanger, whose identity has not been established previously. Apical membrane vesicles of beta intercalated cells purified from rabbit kidney cortex contain both an electroneutral Cl/HCO3 exchange activity and polypeptides that react with antibodies to band 3 on Western blots. Furthermore, both primary cultures of HCO3(-)-secreting intercalated cells and an immortalized cell line derived from these cells express AE1 and have an apical Cl/HCO3 exchanger. Apical membranes purified from these cells contain a 100-kDa polypeptide that cross-reacts with antibody to the cytoplasmic domain of band 3. These data suggest that the apical Cl/HCO3 exchanger of HCO3(-)-secreting intercalated cells is band 3.
Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032.
J S
JS
van Adelsberg
J C
JC
Edwards
Q
Q
al-Awqati
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D027963:Chloride-Bicarbonate Antiporters; D002999:Clone Cells; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007364:Intercalating Agents; D007672:Kidney Cortex / Q000378:metabolism*; D007685:Kidney Tubules, Collecting / Q000378:metabolism; D007700:Kinetics; D037102:Lectins; D008861:Microsomes / Q000378:metabolism*; D008970:Molecular Weight; D019887:Peanut Agglutinin; D011817:Rabbits
D001639:Bicarbonates; D002352:Carrier Proteins; D027963:Chloride-Bicarbonate Antiporters; D007364:Intercalating Agents; D037102:Lectins; D019887:Peanut Agglutinin