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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
2
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pubmed:dateCreated |
2009-1-30
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pubmed:abstractText |
The vectorial transport of ions and water across epithelial cells depends to a large extent on the coordination of the apical and basolateral ion fluxes with energy supply. In this work we provide the first evidence for a regulation by the 5'-AMP-activated protein kinase (AMPK) of the calcium-activated potassium channel KCa3.1 expressed at the basolateral membrane of a large variety of epithelial cells. Inside-out patch-clamp experiments performed on human embryonic kidney (HEK) cells stably transfected with KCa3.1 first revealed a decrease in KCa3.1 activity following the internal addition of AMP at a fixed ATP concentration. This effect was dose dependent with half inhibition at 140 muM AMP in 1 mM ATP. Evidence for an interaction between the COOH-terminal region of KCa3.1 and the gamma1-subunit of AMPK was next obtained by two-hybrid screening and pull-down experiments. Our two-hybrid analysis confirmed in addition that the amino acids extending from Asp(380) to Ala(400) in COOH-terminal were essential for the interaction AMPK-gamma1/KCa3.1. Inside-out experiments on cells coexpressing KCa3.1 with the dominant negative AMPK-gamma1-R299G mutant showed a reduced sensitivity of KCa3.1 to AMP, arguing for a functional link between KCa3.1 and the gamma1-subunit of AMPK. More importantly, coimmunoprecipitation experiments carried out on bronchial epithelial NuLi cells provided direct evidence for the formation of a KCa3.1/AMPK-gamma1 complex at endogenous AMPK and KCa3.1 expression levels. Finally, treating NuLi monolayers with the membrane permeant AMPK activator 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) caused a significant decrease of the KCa3.1-mediated short-circuit currents, an effect reversible by coincubation with the AMPK inhibitor Compound C. These observations argue for a regulation of KCa3.1 by AMPK in a functional epithelium through protein/protein interactions involving the gamma1-subunit of AMPK.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/19052260-10617655,
http://linkedlifedata.com/resource/pubmed/commentcorrection/19052260-10640318,
http://linkedlifedata.com/resource/pubmed/commentcorrection/19052260-10698692,
http://linkedlifedata.com/resource/pubmed/commentcorrection/19052260-10712246,
http://linkedlifedata.com/resource/pubmed/commentcorrection/19052260-10862786,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/19052260-8910387,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/19052260-9759505
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/AICA ribonucleotide,
http://linkedlifedata.com/resource/pubmed/chemical/AMP-Activated Protein Kinases,
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Monophosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Aminoimidazole Carboxamide,
http://linkedlifedata.com/resource/pubmed/chemical/Enzyme Activators,
http://linkedlifedata.com/resource/pubmed/chemical/Intermediate-Conductance...,
http://linkedlifedata.com/resource/pubmed/chemical/KCNN4 protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/PRKAG1 protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Ribonucleotides
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
1522-1563
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pubmed:author |
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pubmed:issnType |
Electronic
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pubmed:volume |
296
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
C285-95
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pubmed:dateRevised |
2010-10-8
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pubmed:meshHeading |
pubmed-meshheading:19052260-Humans,
pubmed-meshheading:19052260-Mutation,
pubmed-meshheading:19052260-Enzyme Activators,
pubmed-meshheading:19052260-Adenosine Monophosphate,
pubmed-meshheading:19052260-Epithelial Cells,
pubmed-meshheading:19052260-Adenosine Triphosphate,
pubmed-meshheading:19052260-Ion Transport,
pubmed-meshheading:19052260-Membrane Potentials,
pubmed-meshheading:19052260-Cells, Cultured,
pubmed-meshheading:19052260-Protein Binding
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