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Regulation of LKB1/STRAD localization and function by E-cadherin

Michael Sebbagh1, Marie-Josée Santoni, Brian Hall

  • 1Cardiovascular Research Center and Department of Microbiology, University of Virginia, Charlottesville, VA 22908, USA. michael.sebbagh@inserm.fr

Current Biology : CB
|December 27, 2008
PubMed

Insights

The LKB1 kinase complex, crucial for tumor suppression, localizes with E-cadherin at adherens junctions. E-cadherin regulates LKB1

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Oncology

Background:

  • LKB1 kinase is a tumor suppressor linked to Peutz-Jeghers syndrome.
  • LKB1, with STRAD and MO25, activates AMPK kinases regulating cell metabolism and polarity.
  • Epithelial polarity depends on E-cadherin-mediated adherens junctions (AJs).

Purpose of the Study:

  • To investigate upstream regulators of LKB1/STRAD complex function.
  • To determine the relationship between E-cadherin and LKB1/STRAD localization and activity.

Main Methods:

  • Immunostaining to visualize protein localization.
  • Fluorescence resonance energy transfer (FRET) to assess protein complex interactions.
  • Analysis of LKB1/STRAD localization, AMPK phosphorylation, and kinase activity in relation to E-cadherin.

Main Results:

  • Active LKB1/STRAD kinase complex colocalizes with E-cadherin at adherens junctions.
  • LKB1/STRAD localization and AMPK phosphorylation are dependent on E-cadherin-mediated AJ maturation.
  • LKB1/STRAD complex kinase activity is independent of E-cadherin.

Conclusions:

  • E-cadherin regulates the localization of the LKB1 complex in polarized epithelial cells.
  • The LKB1 complex functions downstream of E-cadherin in tumor suppression.
  • This provides a novel link between cell adhesion and energy metabolism regulation in cancer.

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