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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
33
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pubmed:dateCreated |
1992-12-22
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pubmed:abstractText |
Human neutrophils and other phagocytes generate superoxide anion (O2-) as a means of destroying ingested microorganisms. O2- is produced by an NADPH-consuming oxidase composed of membrane and cytosolic components. Activation of the NADPH oxidase is absolutely dependent upon GTP, indicating the requirement for a GTP-binding protein in this process. We have utilized a five-step chromatographic procedure to isolate a GTP-binding protein from human neutrophil cytosol which can stimulate NADPH oxidase activity in a cell-free assay. Oxidase enhancing activity was shown to coisolate with this GTP-binding component, which was purified to apparent homogeneity. The GTP-binding protein was identified as Rac 2 by immunological reactivity and amino acid sequencing. Thus, Rac 2 appears to be a third cytosolic component required for human neutrophil NADPH oxidase activation. Recombinant Rac 2 was shown to bind guanine nucleotides in a Mg(2+)-dependent fashion. GDP dissociation rates were determined and shown to be regulated by the free Mg2+ concentration. Rac 2 was found to possess the highest rate of intrinsic GTP hydrolysis of any of the characterized members of the Ras superfamily. The biochemical properties of Rac 2 indicate it is likely to be subject to regulatory cofactors in vivo.
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pubmed:grant |
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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 |
Nov
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pubmed:issn |
0021-9258
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
267
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
23575-82
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:1331090-Chromatography, Affinity,
pubmed-meshheading:1331090-Chromatography, Gel,
pubmed-meshheading:1331090-Chromatography, Ion Exchange,
pubmed-meshheading:1331090-Cytosol,
pubmed-meshheading:1331090-Electrophoresis, Polyacrylamide Gel,
pubmed-meshheading:1331090-GTP Phosphohydrolases,
pubmed-meshheading:1331090-GTP-Binding Proteins,
pubmed-meshheading:1331090-Guanosine 5'-O-(3-Thiotriphosphate),
pubmed-meshheading:1331090-Guanosine Diphosphate,
pubmed-meshheading:1331090-Humans,
pubmed-meshheading:1331090-Immunoblotting,
pubmed-meshheading:1331090-Kinetics,
pubmed-meshheading:1331090-Magnesium,
pubmed-meshheading:1331090-Molecular Weight,
pubmed-meshheading:1331090-NADH, NADPH Oxidoreductases,
pubmed-meshheading:1331090-NADPH Oxidase,
pubmed-meshheading:1331090-Neutrophils,
pubmed-meshheading:1331090-Superoxides,
pubmed-meshheading:1331090-rac GTP-Binding Proteins
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pubmed:year |
1992
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pubmed:articleTitle |
Purification and characterization of Rac 2. A cytosolic GTP-binding protein that regulates human neutrophil NADPH oxidase.
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pubmed:affiliation |
Department Immunology and Cell Biology, Scripps Research Institute, La Jolla, California 92037.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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