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Tyrosine phosphorylation and activation of STAT5, STAT3, and Janus kinases by interleukins 2 and 15

J A Johnston1, C M Bacon, D S Finbloom

  • 1Lymphocyte Cell Biology Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

Proceedings of the National Academy of Sciences of the United States of America
|September 12, 1995
PubMed

Insights

Interleukin 2 (IL-2) and IL-15 activate STAT3 and STAT5 in T cells, distinct from IL-4 signaling. This identifies key Janus kinase (JAK) and signal transducer and activator of transcription (STAT) pathways for T-cell growth factors.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Signaling

Background:

  • Interleukin 2 (IL-2) and IL-15 share biological effects on T cells, binding common receptor subunits.
  • Janus kinase (JAK) and signal transducer and activator of transcription (STAT) pathways are crucial for hematopoietin receptor signaling.

Purpose of the Study:

  • To identify the specific STAT proteins activated by IL-2 and IL-15 in human T cells.
  • To elucidate the distinct JAK-STAT signaling pathways employed by IL-2 and IL-15 compared to IL-4.

Main Methods:

  • Analysis of tyrosine phosphorylation of STAT proteins in human T cells stimulated with IL-2, IL-15, and IL-4.
  • Assessment of DNA-binding activity of activated STAT complexes.
  • Investigation of JAK1 and JAK3 tyrosine phosphorylation in response to cytokine stimulation.

Main Results:

  • IL-2 and IL-15 rapidly induced tyrosine phosphorylation and DNA-binding activation of STAT3 and STAT5 in T cells.
  • IL-4 induced tyrosine phosphorylation and activation of STAT3, but not STAT5.
  • Both IL-2 and IL-15 triggered tyrosine phosphorylation of JAK1 and JAK3.

Conclusions:

  • The JAK and STAT molecules activated by IL-2 and IL-15 are similar but differ from those activated by IL-4.
  • This study defines the specific STAT proteins and signaling pathways utilized by IL-2 and IL-15 for T-cell gene regulation.

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