Document Detail


Ouabain binding to Na+,K+-ATPase relaxes cell attachment and sends a specific signal (NACos) to the nucleus.
MedLine Citation:
PMID:  15216416     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Abstract. In previous work we described a "P-->A mechanism" that transduces occupancy of the pump ( P) by ouabain into changes in phosphorylation, stimulation of mitogen-activated protein kinase (MAPK), and endocytosis of cell-cell- and cell-substrate-attaching molecules ( A), thereby causing a release of the cell from the monolayer. In the present work we try to understand the mechanism of this effect; whether, in order to trigger the P-->A mechanism, ouabain should block the pumping activity of Na(+),K(+)-ATPase as pump, or whether it would suffice that the drug occupies this enzyme as a receptor. We assay a series of drugs known to act on the pump, such as ouabain, digoxin, digitoxin, palytoxin, oligomycin, strophanthidin, neothyoside-A, proscillaridin-A, etc. We gauge their ability to block the pump by measuring the K(+) content in the cells, and their ability to detach the cells from the monolayer by determining the amount of protein remaining in the culturing well. None of the drugs tested was able to cause detachment without stopping the pump. Ouabain also enhances phosphorylation, yet pump inhibition and signal transduction do not seem to be intimately associated in a causal chain, but to occur simultaneously. To investigate the response of the site of cell attachment, we analyze the position of beta-catenin by fluorescence confocal microscopy, and find that this adherent junction-associated molecule is sent to the nucleus, where it is known to act as a transcriptional cofactor.
Authors:
R G Contreras; C Flores-Maldonado; A Lázaro; L Shoshani; D Flores-Benitez; I Larré; M Cereijido
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of membrane biology     Volume:  198     ISSN:  0022-2631     ISO Abbreviation:  J. Membr. Biol.     Publication Date:  2004 Apr 
Date Detail:
Created Date:  2004-06-24     Completed Date:  2005-01-11     Revised Date:  2009-11-03    
Medline Journal Info:
Nlm Unique ID:  0211301     Medline TA:  J Membr Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  147-58     Citation Subset:  IM    
Affiliation:
Department of Physiology, Biophysics and Neurosciences, Av., Center for Research & Advanced Studies, Instituto Politécnico Nacional 2508, 07300, México, D.F., Mexico. rcontrer@fisio.cinvestav.mx
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Adhesion / drug effects,  physiology
Cell Line
Cell Nucleus / drug effects,  physiology*
Cytoskeletal Proteins / metabolism*
Dogs
Enzyme Activation / drug effects
Kidney / cytology,  drug effects,  physiology*
Ouabain / pharmacology*
Protein Binding
Signal Transduction / drug effects,  physiology*
Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors*,  metabolism*
Trans-Activators / metabolism*
Transcription Factors / metabolism*
beta Catenin
Chemical
Reg. No./Substance:
0/Cytoskeletal Proteins; 0/Trans-Activators; 0/Transcription Factors; 0/beta Catenin; 630-60-4/Ouabain; 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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