1987 Fiscal Year Final Research Report Summary
The molecular structure of staphylococcal alpha-toxin and leukocidin and their damaging action on the target cell membranes
| Project/Area Number |
61480143
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
細菌学
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| Research Institution | School of Medicine, Chiba University |
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Principal Investigator |
KATO IWAO Professor School of Medicine, Chiba University, 医学部, 教授 (40012702)
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| Co-Investigator(Kenkyū-buntansha) |
UNEMOTO TSUTOMU Research Institute for Chemobiodynamics, Professor Chiba University (1986 April-, 生物活性研究所, 教授 (30089601)
MORINAGA NAOKO Assistant School of Medicine, Chiba University, 医学部, 助手 (20092108)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Staphylococcal alpha-toxin / leukocidin S and F components / phospholipase A_2 / human promyelocytic leukemia cell (HL-60) / potassium ion channel / phosphorylation / calmodulin / phosphatidylserine / cyclic AMP |
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| Research Abstract |
1. We found recently that staphylococcal alpha-toxin stimulated the activity of target cell membrane associated phospholipase A_2 resulting in causing the perturbation of phospholipids in the cell membranes. Subsequently, the formation of the alpha-toxin hexomer (12 S) pores led to leakage of small ions transmembrane channels.
2. Staphylococcal leukocidin consisting of S and F components caused morphological changes in human promyelocytic leukamia cells(HL-60). The morphological changes induced by leukocidin were rapidly suppressed by the addition of 1 mM CaCl_2. Leukocidin considerably enhanced both ^<45>CaCl_2 uptake in HL-60 cells and the release of K^+ from the cells. Tetraethylammonium chloride, a potassium channel blocker, suppressed not only morphological changes by leukocidin but also potassium release and calcium uptake.
3. Treatment of the HL-60 cell with leukocidin remarkably stimulated phosphorylation of membrane proteins of 120, 103, and 95 KDa. The phosphorylations of these proteins and another protein 88 KDa were activated by the addition of both leukocidin and 1 mM CaCl_2. The phosphorylation of the 88 KDa protein was also observed in the presence of 5 uM calmodulin instead of 1 mM CaCl_2. The phosphorylations of these proteins were neither stimulated by phosphatidylserine and cyclic AMP nor suppressed by H-7 which is a protein kinase C inhibitor. These data suggest that the phosphorylation of an 88 KDa protein by leukocidin is dependent on Ca^<2+> and calmodulin.
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