title: Granulocyte-macrophage colony-stimulating factor and IL-5 activate mitogen-activated protein kinase through Jak2 kinase and phosphatidylinositol 3-kinase in human eosinophils.
abstract: Mitogen-activated protein (MAP) kinases are activated by the sequential activation of Ras, Raf, and MEK (MAP kinase kinase) and regulate a wide variety of cell functions. To determine the kinase cascade for granulocyte-macrophage colony-stimulating factor (GM-CSF)- and IL-5-induced MAP kinase activation in eosinophils, we studied the effect of inhibitors of Jak2 kinase, tyrosine kinases, phosphatidylinositol 3-kinase, and protein kinase C on GM-CSF- and IL-5-induced MAP kinase activation in human eosinophils. GM-CSF and IL-5 activated 40, 42, and 44 kilodalton MAP kinase isoforms in eosinophils. This was indicated by the electrophoretic mobility shift of the three isoforms of MAP kinase in immunoblotting with anti-MAP kinase antibody and also by in-gel MAP kinase assay. MAP kinase activation was time- and dose-dependent, becoming maximal 3 to 15 minutes after stimulation. A Jak2 kinase inhibitor AG-490, a tyrosine kinase inhibitor genistein, and a phosphatidylinositol 3-kinase inhibitor wortmannin inhibited GM-CSF- and IL-5-induced MAP kinase activation in eosinophils, whereas a protein kinase C inhibitor staurosporine had a weak inhibitory effect. Furthermore, AG-490 and genistein prevented GM-CSF-induced tyrosine phosphorylation of Jak2 kinase in eosinophils. Taken together, these results indicate that GM-CSF and IL-5 activate MAP kinases through the signaling pathway of Jak2 kinase-tyrosine phosphorylated beta chain-phosphatidylinositol 3-kinase-Ras in eosinophils.
authors.affiliation: Department of Internal Medicine, Chiba University School of Medicine, Chiba City, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hiraguri
authors.forename: S
authors.initials: S
authors.lastname: Miike
authors.forename: H
authors.initials: H
authors.lastname: Sano
authors.forename: K
authors.initials: K
authors.lastname: Kurasawa
authors.forename: Y
authors.initials: Y
authors.lastname: Saito
authors.forename: I
authors.initials: I
authors.lastname: Iwamoto
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004804:Eosinophils / Q000502:physiology*; D019833:Genistein / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006801:Humans; D015848:Interleukin-5 / Q000494:pharmacology*; D053614:Janus Kinase 2; D009570:Nitriles / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D015398:Signal Transduction; D019311:Staurosporine / Q000494:pharmacology; D020032:Tyrphostins; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D004791:Enzyme Inhibitors; D015848:Interleukin-5; D009570:Nitriles; D011518:Proto-Oncogene Proteins; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D019833:Genistein; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D019311:Staurosporine; D000077191:Wortmannin