| Project/Area Number |
09672270
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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 |
Biological pharmacy
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| Research Institution | National Institute of Health Sciences |
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Principal Investigator |
TESHIMA Reiko National Institute of Health Sciences, Division of Biochemistry and Immunochemistry, Senior Scientist, 機能生化学部, 研究員 (50132882)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | IgE receptor / Ectokinases / Mast cells / Signal transduction / Degranulation / Calcium signal |
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| Research Abstract |
We examined the effects of K252b, an ectoprotein kinase inhibitor of microbial origin, on the activation of RBL-2H3 cells by cross-linking of IgB receptors or by the Ca^<2+> ionophore A23187. Analysis of phosphorylation of ectoproteins following IgE receptor cross-linking revealed that K252b mainly inhibited the phosphorylation of a 130-kDa protein. The inhibitor simultaneously inhibited the degranulation and the sustained increase in the cytosolic calcium ion concentration even afteraddition of Ag. In contrast, K252b did not inhibit the increase in degranulation and cytosolic calcium ion concentration caused by stimulation with A23187. Permeation of K252b into RBL-2H3 cells, assessed by fluorescence intensity, was very low. K252b also inhibited de-granulation caused by IgE receptor cross-linking in human basophils, but did not inhibit the de-granuation caused by A23187. Thus, our findings suggest that the effects of K252b may be mediated by outersurface-bound or -anchored K252b-sensitive molecules on RBL-2H3 cells and human basophils, and that the phosphorylation of ectoprotein may be involve a transmembrane influx of Ca^<2+> by IgE rece-ptor cross-linking.
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