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Cellular settings mediating Src Substrate switching between focal adhesion kinase tyrosine 861 and

Andreas Wortmann1, Yaowu He2, Melinda E Christensen2

  • 1Mater Medical Research Institute, Aubigny Place, Raymond Terrace, South Brisbane, Queensland 4101; Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059.

The Journal of Biological Chemistry
|October 14, 2011
PubMed

Insights

Cell signaling proteins Src family kinases (SFKs) and focal adhesion kinase (FAK) switch targets, impacting cell attachment and morphology. This SFK substrate switching, involving CDCP1, is crucial in cancer progression.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Src family kinases (SFKs) and focal adhesion kinase (FAK) interactions are vital for cell adhesion dynamics.
  • CUB-domain-containing protein 1 (CDCP1), an SFK substrate, shows differential phosphorylation during cell attachment changes.
  • The precise mechanisms of SFK-mediated CDCP1 phosphorylation remain unclear.

Purpose of the Study:

  • To elucidate the molecular mechanisms of SFK-mediated CDCP1 phosphorylation.
  • To investigate the competitive substrate relationship between FAK and CDCP1 for SFKs.
  • To explore the role of SFK substrate switching in cell morphology and cancer progression.

Main Methods:

  • Utilized HeLa cells with stable CDCP1 expression.
  • Analyzed phosphorylation status of FAK-Tyr-861 and CDCP1-Tyr-734, -743, -762.
  • Investigated SFK engagement with CDCP1 and Src-Tyr-416 phosphorylation.
  • Examined cell morphology changes.
  • Studied endogenous SFK switching in colorectal cancer cell lines (SW480).
  • Assessed potential trimeric complex formation involving FAK, Src, and CDCP1.

Main Results:

  • Stable CDCP1 expression led to SFK-mediated phosphorylation of CDCP1-Tyr-734 and decreased FAK-Tyr-861 phosphorylation.
  • SFK substrate switching was dependent on CDCP1 expression levels and CDCP1-Tyr-734 phosphorylation.
  • SFK engagement with CDCP1 increased Src-Tyr-416 phosphorylation and induced fibroblastic morphology.
  • SFK switching was observed in colorectal cancer cells during adhesion changes.
  • Silencing CDCP1 in SW480 cells increased FAK-Tyr-861 phosphorylation and promoted epithelial morphology.
  • FAK did not appear to form a trimeric complex with Src and CDCP1.

Conclusions:

  • FAK-Tyr-861 and CDCP1-Tyr-734 are competitive SFK substrates.
  • SFKs dynamically switch between FAK and CDCP1 phosphorylation sites based on cellular context.
  • This SFK substrate switching influences cell morphology and is relevant to colorectal cancer progression.
  • The findings reveal novel dynamics in SFK-mediated cell signaling pathways.

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