The activation of the Jak-STAT 1 signaling pathway by IL-5 in eosinophils

Konrad Pazdrak, Susan Stafford, Rafeul Alam

Research output: Contribution to journalArticlepeer-review

123 Scopus citations

Abstract

The intracellular signal transduction of IL-5 in eosinophils is unknown. The objective of this study was to investigate the involvement of the newly discovered Jak-STAT pathway in the IL-5 signal transduction mechanism. Eosinophils were purified from peripheral blood by discontinuous Percoll gradients and stimulated with IL-5. The involvement of Jak 2 was investigated by immunoprecipitation followed by immunoblotting for tyrosine phosphorylation. The activation of Jak 2 was studied by autophosphorylation of the immunoprecipitated kinase. Jak 2 was tyrosine phosphorylated within 1 to 3 min after stimulation of eosinophils with IL-5. Further, the immunoprecipitated Jak 2 obtained from IL-5-stimulated cells underwent autophosphorylation. Jak 2 coprecipitated with the β-subunit of the IL-5 receptor, suggesting a physical association of the kinase with the receptor. The nuclear factor STAT-1 (p91) was investigated by immunoprecipitation followed by immunoblotting for tyrosine phosphorylation. STAT-1 was tyrosine phosphorylated within 15 min of IL-5 stimulation. The presence of STAT-1 in the nuclear extract was studied by electrophoretic mobility shift assay. IL- 5 induced two proteins that bound to the γ-activating sequence. In the presence of an anti-STAT-1 Ab, the band was supershifted. Thus, we demonstrated that IL-5 activated the Jak 2-STAT 1 signaling pathway in eosinophils. We speculate that the Jak 2-STAT 1 pathway may be involved in the activation of IL-5 inducible genes in eosinophils.

Original languageEnglish (US)
Pages (from-to)397-402
Number of pages6
JournalJournal of Immunology
Volume155
Issue number1
StatePublished - 1995

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Fingerprint

Dive into the research topics of 'The activation of the Jak-STAT 1 signaling pathway by IL-5 in eosinophils'. Together they form a unique fingerprint.

Cite this