Signal transduction through interferon-gamma receptor on human eosinophils.
BACKGROUND
We reported on the constitutive interferon-gamma receptor (IFN-gammaR) expression on eosinophils. But signal transduction through IFN-gammaR on eosinophils remains to be elucidated. In this study, we examined the involvement of the Jak/Stat pathway in the signaling of eosinophils after IFN-gammaR conjugation by the ligand binding.


METHODS
Purified peripheral eosinophils were stimulated with IFN-gamma at 37 degrees C for 1-60 min. Tyrosine phosphorylation of IFN-gammaR, Jak1, Jak2, and Stat1alpha was examined by immunoblotting. Gel-shift assay was also examined to show the formation of Stat1alpha-DNA complexes.


RESULTS
We show that binding of IFN-gamma to human eosinophils initiated a series of events that resulted in the rapid tyrosine phosphorylation of not only the IFN-gammaRalpha chain but also Jak1, Jak2, and Stat1alpha. In addition, IFN-gamma enhanced the DNA-binding activity of Stat1alpha.


CONCLUSIONS
These data indicate that IFN-gamma affects eosinophils through its specific receptor and utilizes the Jak/Stat pathway as its mode of signaling.
Ochiai
K
K
Internal Medicine and Pediatrics, Toho University School of Medicine, Sakura Hospital, Sakura, Japan.
Ishihara
C
C
Tomioka
H
H
D004268:DNA-Binding Proteins / Q000276:immunology; D004804:Eosinophils / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D011505:Protein-Tyrosine Kinases / Q000276:immunology; D011518:Proto-Oncogene Proteins; D017471:Receptors, Interferon / Q000276:immunology*; D050794:STAT1 Transcription Factor; D015398:Signal Transduction / Q000276:immunology*; D015534:Trans-Activators / Q000276:immunology; D000096743:Interferon gamma Receptor
D004268:DNA-Binding Proteins; D007371:Interferon-gamma; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D017471:Receptors, Interferon; D050794:STAT1 Transcription Factor; D015534:Trans-Activators; D000096743:Interferon gamma Receptor; C494079:STAT1 protein, human; C507904:JAK1 protein, human; C507924:JAK2 protein, human