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Analysis of Wnt7a-stimulated JNK activity and cJun phosphorylation in non-small cell lung cancer cells

Lynn E Heasley1, Robert A Winn

  • 1Department of Medicine, University of Colorado Health Sciences Centre, Denver, USA.

Methods in Molecular Biology (Clifton, N.J.)
|December 23, 2008
PubMed

Insights

The cJun N-terminal kinases (JNKs) pathway is activated by Wnt proteins and growth factors. A new assay using cJun substrate binding reliably measures JNK activity in stimulated cells.

Area of Science:

  • Cell biology
  • Molecular signaling
  • Cancer research

Background:

  • cJun N-terminal kinases (JNKs) are crucial signaling molecules activated by various stimuli, including growth factors and morphogens like Wnt proteins.
  • JNK signaling mediates essential cellular processes such as epithelial cell polarity and tissue development.
  • Previous research indicated Wnt-7a and Fzd9 activate JNKs, promoting epithelial differentiation in lung cancer, but measuring this modest activation is challenging.

Purpose of the Study:

  • To develop a reliable method for assessing JNK pathway activity stimulated by Wnt proteins and growth factors.
  • To overcome limitations of traditional immunoblotting techniques for detecting subtle JNK activation.

Main Methods:

  • Investigated the interaction between JNKs and their substrate, cJun.
  • Developed a novel assay based on the binding affinity of JNKs to cJun.

Main Results:

  • Demonstrated that the binding of JNKs to their substrate cJun can be utilized as a direct measure of JNK activity.
  • Established a simple and dependable assay for quantifying JNK activation in response to Wnt proteins and growth factors.
  • This method proves more reliable than anti-phospho-JNK immunoblotting for modest JNK activation.

Conclusions:

  • The JNK-cJun interaction provides a robust basis for a new assay to measure JNK pathway activity.
  • This assay facilitates the study of JNK roles in cellular processes stimulated by growth factors and morphogens.
  • The findings offer a valuable tool for cancer research, particularly in understanding lung cancer cell differentiation.

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