Document Detail


Gastric parietal cell acid secretion in mice can be regulated independently of H/K ATPase endocytosis.
MedLine Citation:
PMID:  15236181     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND & AIMS: Gastric parietal cells secrete acid into the lumen of the stomach. They express a proton pump, the gastric H(+)/K(+) ATPase, the activity of which is tightly regulated. The H(+)/K(+) ATPase traffics between an intracytoplasmic compartment (tubulovesicles) in quiescent parietal cells and the apical plasma membrane in activated cells. These trafficking events are considered to contribute to the control of acid secretion by modulating access to apical K(+) and Cl(-) conductances that are required for transmembrane H(+) ion transport by the H(+)/K(+) ATPase. Here, we have determined whether the control of acid secretion in vivo requires membrane trafficking of the H(+)/K(+) ATPase. METHODS: We developed mice that only express an H(+)/K(+) ATPase beta subunit in which a putative tyrosine-based endocytosis motif in the cytoplasmic tail is mutated. Location of the H(+)/K(+) ATPase and parietal cell ultrastructure and gastric acid secretion were then examined. RESULTS: Parietal cells of these mice lacked a tubulovesicular compartment, and the H(+)/K(+) ATPase was resident exclusively on the apical plasma membrane. Despite the inability of the H(+)/K(+) ATPase to be endocytosed, the gastric acid secretory response to histamine or an antagonist was very similar to that of wild-type mice, indicating that control of H(+)/K(+) ATPase activity can occur independently of intracellular trafficking. CONCLUSIONS: We were able to dissociate the regulation of H(+)/K(+) ATPase activity from intracellular trafficking of the protein. Thus, it is likely that direct regulation of apical K(+) and Cl(-) conductances are sufficient to control gastric acid secretion.
Authors:
Nhung V Nguyen; Paul A Gleeson; Nathalie Courtois-Coutry; Michael J Caplan; Ian R Van Driel
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Gastroenterology     Volume:  127     ISSN:  0016-5085     ISO Abbreviation:  Gastroenterology     Publication Date:  2004 Jul 
Date Detail:
Created Date:  2004-07-05     Completed Date:  2004-09-28     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0374630     Medline TA:  Gastroenterology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  145-54     Citation Subset:  AIM; IM    
Affiliation:
The Russell Grimwade School of Biochemistry and Molecular Biology, The University of Melbourne, Australia.
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MeSH Terms
Descriptor/Qualifier:
Adenosine Triphosphatases / genetics,  physiology
Animals
Biological Transport / genetics,  physiology
Cell Membrane / physiology
Endocytosis / physiology*
Gastric Acid / secretion*
Gene Expression
Mice
Mice, Transgenic
Parietal Cells, Gastric / metabolism*
Sodium-Potassium-Exchanging ATPase / genetics,  metabolism*
Chemical
Reg. No./Substance:
EC 3.6.1.-/Adenosine Triphosphatases; EC 3.6.3.9/Sodium-Potassium-Exchanging ATPase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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