Source:http://linkedlifedata.com/resource/pubmed/id/12660145
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
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| pubmed:dateCreated |
2003-6-2
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| pubmed:abstractText |
The influences of the gastric H+/K+ pump on organelle pH during trafficking to and from the plasma membrane were investigated using HEK-293 cells stably expressing the alpha- and beta-subunits of human H+/K+-ATPase (H+/K+-alpha,beta cells). The pH values of trans-Golgi network (pHTGN) and recycling endosomes (pHRE) were measured by transfecting H+/K+-alpha,beta cells with the pH-sensitive GFP pHluorin fused to targeting sequences of either TGN38 or synaptobrevin, respectively. Immunofluorescence showed that H+/K+-ATPase was present in the plasma membrane, TGN, and RE. The pHTGN was similar in both H+/K+-alpha,beta cells (pHTGN 6.36) and vector-transfected ("mock") cells (pHTGN 6.34); pHRE was also similar in H+/K+-alpha,beta (pHRE 6.40) and mock cells (pHRE 6.37). SCH28080 (inhibits H+/K+-ATPase) caused TGN to alkalinize by 0.12 pH units; subsequent addition of bafilomycin (inhibits H+ v-ATPase) caused TGN to alkalinize from pH 6.4 up to a new steady-state pHTGN of 7.0-7.5, close to pHcytosol. Similar results were observed in RE. Thus H+/K+-ATPases that trafficked to the plasma membrane were active but had small effects to acidify the TGN and RE compared with H+ v-ATPase. Mathematical modeling predicted a large number of H+ v-ATPases (8000) active in the TGN to balance a large, passive H+ leak (with PH approximately 10-3 cm/s) via unidentified pathways out of the TGN. We propose that in the presence of this effective, though inefficient, buffer system in the Golgi and TGN, H+/K+-ATPases (estimated to be approximately 4000 active in the TGN) and other transporters have little effect on luminal pH as they traffic to the plasma membrane.
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| pubmed:grant | |
| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical | |
| pubmed:status |
MEDLINE
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| pubmed:month |
Jul
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| pubmed:issn |
0363-6143
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:volume |
285
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
C205-14
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| pubmed:dateRevised |
2007-11-14
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| pubmed:meshHeading |
pubmed-meshheading:12660145-Acid-Base Equilibrium,
pubmed-meshheading:12660145-Animals,
pubmed-meshheading:12660145-Cell Membrane,
pubmed-meshheading:12660145-Cell Membrane Permeability,
pubmed-meshheading:12660145-Cells, Cultured,
pubmed-meshheading:12660145-Endosomes,
pubmed-meshheading:12660145-H(+)-K(+)-Exchanging ATPase,
pubmed-meshheading:12660145-Humans,
pubmed-meshheading:12660145-Hydrogen-Ion Concentration,
pubmed-meshheading:12660145-Kidney,
pubmed-meshheading:12660145-Luminescent Proteins,
pubmed-meshheading:12660145-Protein Transport,
pubmed-meshheading:12660145-Protons,
pubmed-meshheading:12660145-Rabbits,
pubmed-meshheading:12660145-Secretory Vesicles,
pubmed-meshheading:12660145-Transfection,
pubmed-meshheading:12660145-trans-Golgi Network
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| pubmed:year |
2003
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| pubmed:articleTitle |
pH of TGN and recycling endosomes of H+/K+-ATPase-transfected HEK-293 cells: implications for pH regulation in the secretory pathway.
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| pubmed:affiliation |
Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA. machen@socrates.berkeley.edu
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| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.
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