1996 Fiscal Year Final Research Report Summary
Roles of GTP-binding proteins in dynamics of secretory granules in human neutrophils
| Project/Area Number |
07807101
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hematology
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| Research Institution | Kochi Medical School |
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Principal Investigator |
KOBAYASHI Toshihiro Kochi Medical School Faculty of Medicine, Assistant, 医学部, 助手 (40153621)
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| Co-Investigator(Kenkyū-buntansha) |
OKADA Teruhiko Kochi Medical School Faculty of Medicine, Associate Professor, 医学部, 助教授 (00025628)
SEGUCHI Harumichi Kochi Medical School Faculty of Medicine, Professor, 医学部, 教授 (90030866)
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| Project Period (FY) |
1995 – 1996
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| Keywords | neutrophils / signal transduction / GTP-binding proteins / NADPH oxidase / alkaline phosphatase |
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| Research Abstract |
Human neutrophils possess alkaline phosphatase-containing intracellular granules which are up-regulated to the cell surface upon stimulation (Kobayashi and Robinson. 1991, J.Cell Biol.113 : 743-756). The mechanisms of the intracellular dynamics of these granules has not fully elucidated. The aim of the present study is to investigate the participation of GTP-binding proteins in reorganization and exocytosis of the alkaline phosphatase-containing granules using electropermeabilized cells. In biochemical assays, intact neutrophils showed the up-regulation of alkaline phosphatase activity to the cell surface upon stimulation with AIF_4^- and N-formy1 peptide. This up-regulation was inhibited by the treatment of cells with pertussis toxin or botulinum toxin. Alkaline phosphatase activity was also up-regulated in electropermeabilized cells stimulated with GTPgammaS,but not with GDPbetaS.In cytochemical studies, alkaline phosphatase-containing granules were localized dispersedly throughout the cytoplasm in unstimulated electromeabilized neutrophils. Upon stimulation with GTPgammaS,but not with GDPbetaS,these granules fused to from elongated tubular structures which were associated with the plasma membrane. Nocodazole perturbed the reorganization of the alkaline phosphatase-containing granules upon stimulation with GTPgammaS.Results from this study indicate that GTP-binding proteins participate in reorganization and exocytosis of the alkaline phosphatase-containing granules which are associated with the microtubules in electropermeabilized human neutrophils.
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