Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1999-3-16
pubmed:abstractText
The Na,K-ATPase is specifically inhibited by the cardiac glycoside, ouabain. Via a largely undefined mechanism, the ouabain affinity of the Na,K-ATPase can be manipulated by mutating the residues at the borders of the first extracellular (M1-M2) loop of the alpha subunit [Price, E. M., Rice, D. A., and Lingrel, J. B. (1990) J. Biol. Chem. 265, 6638-6641]. To address this issue, we compared the effects of two combinations of charged residues at the M1-M2 loop border, R113, D124 and D113,R124 (numbered according to the rat alpha1 subunit), on the ouabain sensitivity of the alpha1 and alpha2 isoforms. We report that ouabain sensitivity is dependent not only upon the identity of the residues at the M1-M2 loop border but also upon the context into which they are introduced. Furthermore, at low concentrations of ATP, the identity of the residues at the M1-M2 loop border affects the regulation of ATP hydrolysis by potassium in an isoform-specific manner. Analysis of chimeric alpha subunits reveals that the effects of potassium are determined primarily by the interaction of the N-terminus and M1-M2 loop with the C-terminal third of the alpha subunit. M1-M2 loop border residues may, therefore, influence ouabain sensitivity indirectly by altering the stability or structure of the intermediate of the Na,K-ATPase catalytic cycle which is competent to bind ouabain.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2494-505
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:10029544-Adenosine Triphosphate, pubmed-meshheading:10029544-Amino Acid Sequence, pubmed-meshheading:10029544-Amino Acids, pubmed-meshheading:10029544-Animals, pubmed-meshheading:10029544-Cell Division, pubmed-meshheading:10029544-Drug Resistance, pubmed-meshheading:10029544-Enzyme Activation, pubmed-meshheading:10029544-HeLa Cells, pubmed-meshheading:10029544-Humans, pubmed-meshheading:10029544-Isoenzymes, pubmed-meshheading:10029544-Molecular Sequence Data, pubmed-meshheading:10029544-Mutagenesis, Site-Directed, pubmed-meshheading:10029544-Ouabain, pubmed-meshheading:10029544-Peptide Fragments, pubmed-meshheading:10029544-Potassium, pubmed-meshheading:10029544-Protein Structure, Secondary, pubmed-meshheading:10029544-Rats, pubmed-meshheading:10029544-Recombinant Fusion Proteins, pubmed-meshheading:10029544-Sodium-Potassium-Exchanging ATPase, pubmed-meshheading:10029544-Transfection
pubmed:year
1999
pubmed:articleTitle
Isoform-specific effects of charged residues at borders of the M1-M2 loop of the Na,K-ATPase alpha subunit.
pubmed:affiliation
Department of Microbiology, University of Massachusetts, Amherst 01003, USA. mcoppi@microbio.umass.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't