Identification of a basolateral Cl-/HCO3- exchanger specific to gastric parietal cells.
The basolateral Cl(-)/HCO(3)(-) exchanger in parietal cells plays an essential role in gastric acid secretion mediated via the apical gastric H(+)-K(+)-ATPase. Here, we report the identification of a new Cl(-)/HCO(3)(-) exchanger, which shows exclusive expression in mouse stomach and kidney, with expression in the stomach limited to the basolateral membrane of gastric parietal cells. Tissue distribution studies by RT-PCR and Northern hybridizations demonstrated the exclusive expression of this transporter, also known as SLC26A7, to stomach and kidney, with the stomach expression significantly more abundant. No expression was detected in the intestine. Cellular distribution studies by RT-PCR and Northern hybridizations demonstrated predominant localization of SLC26A7 in gastric parietal cells. Immunofluorescence labeling localized this exchanger exclusively to the basolateral membrane of gastric parietal cells, and functional studies in oocytes indicated that SLC26A7 is a DIDS-sensitive Cl(-)/HCO(3)(-) exchanger that is active in both acidic and alkaline pH(i). On the basis of its unique expression pattern and function, we propose that SLC26A7 is a basolateral Cl(-)/HCO(3)(-) exchanger in gastric parietal cells and plays a major role in gastric acid secretion.
Department of Medicine, University of Cincinnati, Cincinnati 45267, USA.
Snezana
S
Petrovic
Xie
X
Ju
Sharon
S
Barone
Ursula
U
Seidler
Seth L
SL
Alper
Hannes
H
Lohi
Juha
J
Kere
Manoocher
M
Soleimani
D000818:Animals; D017920:Antiporters / Q000235:genetics* / Q000378:metabolism*; D015153:Blotting, Western; D027963:Chloride-Bicarbonate Antiporters; D005455:Fluorescent Antibody Technique; D005744:Gastric Acid / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000378:metabolism; D051379:Mice; D009928:Organ Specificity; D010295:Parietal Cells, Gastric / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000076988:Sulfate Transporters
D017920:Antiporters; D027963:Chloride-Bicarbonate Antiporters; D012333:RNA, Messenger; C455626:SLC26A7 protein, human; C486743:Slc26a7 protein, mouse; D000076988:Sulfate Transporters