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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
1-3
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pubmed:dateCreated |
2005-1-31
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pubmed:abstractText |
The plasma membrane Ca(2+)-Mg(2+)-ATPase is a Ca(2+)-pump that expels Ca2+ from cells. Here we report caloxin 1A1-a novel peptide inhibitor (Ki=100 microM) of plasma membrane Ca(2+)-pump-obtained by screening a cysteine bridge-constrained random peptide library for binding to the first extracellular domain of plasma membrane Ca(2+)-pump. Dithiothreitol removed the inhibition indicating that the constraint imposed by the cysteine bridge is required for the inhibition. Caloxin 1A1 also inhibited the fast twitch sarcoplasmic reticulum Ca(2+)-Mg(2+)-ATPase although weakly. Glutathione dimers (containing a cysteine bridge) inhibited the Ca(2+)-Mg(2+)-ATPase activity of sarcoplasmic reticulum Ca(2+)-Mg(2+)-ATPase, but not that of plasma membrane Ca(2+)-pump. Caloxin 1A1 stabilised Ca(2+)-dependent formation of the acid stable 140-kDa acylphosphate which is a partial reaction of this enzyme. Thus caloxin 1A1 inhibits the plasma membrane Ca(2+)-pump by perturbing the first extracellular domain indicating that the transmembrane domains 1 and 2 play a role in its reaction cycle. This finding is consistent with rearrangements that occur in transmembrane helices 1 and 2 during reaction cycle of sarcoplasmic reticulum Ca(2+)-pump. Caloxin 1A1 caused an increase in cytosolic Ca2+ concentration in endothelial cells.
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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 |
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pubmed:status |
MEDLINE
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pubmed:month |
Jan
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pubmed:issn |
0014-2999
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
31
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pubmed:volume |
508
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1-6
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:15680248-Amino Acid Sequence,
pubmed-meshheading:15680248-Animals,
pubmed-meshheading:15680248-Ca(2+) Mg(2+)-ATPase,
pubmed-meshheading:15680248-Calcium,
pubmed-meshheading:15680248-Cell Membrane,
pubmed-meshheading:15680248-Cells, Cultured,
pubmed-meshheading:15680248-Coronary Vessels,
pubmed-meshheading:15680248-Dithiothreitol,
pubmed-meshheading:15680248-Dose-Response Relationship, Drug,
pubmed-meshheading:15680248-Endothelial Cells,
pubmed-meshheading:15680248-Erythrocyte Membrane,
pubmed-meshheading:15680248-Glutathione,
pubmed-meshheading:15680248-Humans,
pubmed-meshheading:15680248-Kinetics,
pubmed-meshheading:15680248-Membrane Proteins,
pubmed-meshheading:15680248-Molecular Sequence Data,
pubmed-meshheading:15680248-Peptide Library,
pubmed-meshheading:15680248-Peptides,
pubmed-meshheading:15680248-Phosphates,
pubmed-meshheading:15680248-Sarcoplasmic Reticulum,
pubmed-meshheading:15680248-Swine
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pubmed:year |
2005
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pubmed:articleTitle |
A novel plasma membrane Ca(2+)-pump inhibitor: caloxin 1A1.
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pubmed:affiliation |
Department of Biology, McMaster University, Hamilton, Ontario, Canada L8N 3Z5.
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pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, Non-U.S. Gov't
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