Src family-selective tyrosine kinase inhibitor, PP1, inhibits both Fc epsilonRI- and Thy-1-mediated activation of rat basophilic leukemia cells
Language English Country Germany Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
9295022
DOI
10.1002/eji.1830270810
Knihovny.cz E-resources
- MeSH
- Leukemia, Basophilic, Acute enzymology immunology MeSH
- Thy-1 Antigens metabolism MeSH
- Basophils drug effects enzymology immunology MeSH
- Phosphorylation MeSH
- Enzyme Inhibitors pharmacology MeSH
- Rats MeSH
- Mast Cells drug effects enzymology immunology MeSH
- Mice MeSH
- Tumor Cells, Cultured MeSH
- Pyrazoles pharmacology MeSH
- Pyrimidines pharmacology MeSH
- Receptors, IgE metabolism MeSH
- src-Family Kinases antagonists & inhibitors MeSH
- In Vitro Techniques MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- 4-amino-5-(4-methylphenyl)-7-(tert-butyl)pyrazolo(3,4-d)pyrimidine MeSH Browser
- Thy-1 Antigens MeSH
- Enzyme Inhibitors MeSH
- Pyrazoles MeSH
- Pyrimidines MeSH
- Receptors, IgE MeSH
- src-Family Kinases MeSH
Cross-linking of the surface receptor with high affinity for IgE (Fc epsilonRI) by multivalent antigen/immunoglobulin E complexes, as well as aggregation of Thy-1 glycoprotein by monoclonal antibodies lead in rat basophilic leukemia cells, clone RBL-2H3, to tyrosine phosphorylation of several cellular proteins, followed by a release of secretory components. To investigate the molecular mechanisms of Fc epsilonRI- and Thy-1-mediated transmembrane signaling and to map a step at which they converge into a common secretory pathway, we used a novel Src family-selective tyrosine kinase inhibitor, 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1), and analyzed its inhibitory activity on cell activation. Here we show that in RBL-2H3 cells PP1 demonstrates substrate specificity for a Src family kinase Lyn. In immunocomplex kinase assays in vitro, PP1 inhibited the Lyn kinase activity at nanomolar levels without any effect on Syk kinase activity. However, in RBL cells activated via aggregation of Fc epsilonRI, phosphorylation of both Syk and Lyn kinases was inhibited. Fc epsilonRI- and Thy-1-mediated early (protein-tyrosine phosphorylation) and late (release of beta-hexosaminidase) activation events were similarly affected by PP1. The inhibition was specific for membrane receptor-mediated signaling and was not observed in cells activated by an exposure to pervanadate. The combined data suggest that activation of Lyn is the early activation step at which the Fc epsilonRI- and Thy-1-mediated activation pathways of mast cells and basophils may converge.
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