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c-Src activates both STAT1 and STAT3 in PDGF-stimulated NIH3T3 cells

P Cirri1, P Chiarugi, F Marra

  • 1Dipartimento di Scienze Biochimiche, Instituto di Medicina Interna, Università di Firenze, Italy.

Biochemical and Biophysical Research Communications
|November 5, 1997
PubMed

Insights

Cellular Src tyrosine kinase activates STAT1 and STAT3 signaling pathways. This study demonstrates c-Src

Area of Science:

  • Cellular biology
  • Molecular signaling
  • Signal transduction pathways

Background:

  • Signal transducer and activator of transcription (STAT) proteins, specifically STAT1 and STAT3, are activated by growth factors like PDGF and EGF.
  • STAT activation involves tyrosine phosphorylation, dimerization, and nuclear translocation to act as transcription activators.
  • The role of Src family kinases in STAT activation, particularly in response to growth factors, is not fully understood.

Purpose of the Study:

  • To investigate the role of cellular Src (c-Src) tyrosine kinase in the activation of STAT1 and STAT3 signaling pathways.
  • To determine if c-Src directly interacts with STAT1 and STAT3 during growth factor-induced signaling.

Main Methods:

  • Utilizing NIH3T3 cells stimulated with Platelet-Derived Growth Factor (PDGF).
  • Overexpression of c-Src and dominant-negative Src constructs.
  • Assessing tyrosine phosphorylation and DNA binding activity of STAT1 and STAT3.
  • Performing co-immunoprecipitation assays to detect protein interactions.

Main Results:

  • c-Src overexpression up-regulated both tyrosine phosphorylation and DNA binding activity of STAT1 and STAT3.
  • Dominant-negative Src expression inhibited STAT1 and STAT3 activation.
  • STAT1 was found to co-immunoprecipitate with c-Src, indicating a direct interaction.

Conclusions:

  • Cellular Src tyrosine kinase plays a significant role in the activation of both STAT1 and STAT3.
  • c-Src directly interacts with STAT1, suggesting a mechanism for STAT activation in PDGF signaling.
  • These findings elucidate a novel role for c-Src in growth factor receptor signal transduction.

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