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RasGRF suppresses Cdc42-mediated tumour cell movement, cytoskeletal dynamics and transformation

Fernando Calvo1, Victoria Sanz-Moreno, Lorena Agudo-Ibáñez

  • 1Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas-IDICAN-Universidad de Cantabria, Departamento de Biología Molecular, Facultad de Medicina, Santander, 39011, Cantabria, Spain.

Nature Cell Biology
|June 21, 2011
PubMed

Insights

RasGRF guanine nucleotide exchange factors (GEFs) regulate cell movement by inhibiting Cdc42 activation. This finding reveals RasGRFs as key negative regulators of Cdc42, impacting cell morphology and invasion.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Tumor cell migration occurs in rounded or mesenchymal (elongated) forms.
  • Rho family GTPases, including Rac1, Cdc42, and Rho, control these distinct cell movement modes.
  • Guanine nucleotide exchange factors (GEFs) are critical regulators of Rho GTPase activity.

Purpose of the Study:

  • To investigate the role of GEFs in regulating cell morphology and movement.
  • To identify specific GEFs involved in the switch between rounded and mesenchymal cell migration.
  • To elucidate the mechanism by which RasGRF2 influences Cdc42 activation and cell behavior.

Main Methods:

  • siRNA screening of GEF-encoding genes.
  • Analysis of cell morphology and movement in 3D environments.
  • Biochemical assays to assess GTPase activation and protein interactions (e.g., RasGRF2 binding to Cdc42).

Main Results:

  • RasGRF2 was identified as a regulator of the conversion between elongated and rounded cell movement.
  • RasGRF2 inhibits Cdc42 activation, independent of its Ras-activating function.
  • RasGRF2 and RasGRF1 directly bind to Cdc42, preventing its activation by other GEFs.
  • RasGRFs were shown to negatively regulate Cdc42 activation, impacting actin spike formation, transformation, and invasion.

Conclusions:

  • Ras guanine nucleotide exchange factors (RasGRFs) function as negative regulators of Cdc42 activation.
  • This mechanism of Cdc42 inhibition by RasGRFs controls cell morphology and invasive behaviors.
  • The findings highlight a novel regulatory pathway for cell migration and potential therapeutic targets in cancer.

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