1993 Fiscal Year Final Research Report Summary
A search with Pertussis Toxin for Cellular Factors Affecting the Properties of GTP-Binding Protein
| Project/Area Number |
04680184
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
代謝生物化学
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| Research Institution | University of Tokyo |
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Principal Investigator |
HAZEKI Osamu University of Tokyo, Faculty of Pharmaceutical Sciences, Assistant, 薬学部, 助手 (80142751)
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| Project Period (FY) |
1992 – 1993
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| Keywords | PERTUSSIS TOXIN / ADP-RIBOSYLATION / GTP-BINDING PROTEIN / LIPOPOLYSACCHARIDE / NEUTROPHILS |
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| Research Abstract |
Pertussis toxin-catalyzed ADP-ribosylation of membrane Gi (inhibitory guanine nucleotide-binding protein) was examined on the hypothesis that the rate of modification may reflect the membrane environment of Gi. Incubation of saponin-permeabilized neutrophils with activated pertussis toxin and NAD led to rapid ADP-ribosylation of cellular Gi. The rate of ADP-ribosylation was found to be decreased by prior treatment of the cells with lipopolysaccharide (LPS), in spite that the cellular content of Gi was unaffected by the treatment. Receptor-mediated activation of Gi by formyl-peptide caused no change in the rate of the modification. LPS potentiated the formyl-peptide-induced activation of phospholipase C and increase in intracellular Ca^<++> in intact neutrophils. The changes were accompanied by the increased GDP-GTP exchange and GTP-hydrolyzing activities of Gi in membrane preparations. These results suggest that LPS-treatment of neutrophils causes Gi quantitative change or altered interaction with other cellular component, which affects the rate of pertussis toxin-catalyzed ADP-ribosylation.
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