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Annexin A2 phosphorylation mediates cell scattering and branching morphogenesis via cofilin Activation

Marjo de Graauw1, Ine Tijdens, Mirjam B Smeets

  • 1Division of Toxicology, Leiden/Amsterdam Center for Drug Research, Gorlaeus Laboratoria, P.O. Box 9502, 2300 RA Leiden, The Netherlands.

Molecular and Cellular Biology
|December 12, 2007
PubMed

Insights

Phosphorylation of annexin A2 (AnxA2) at Tyr23 is crucial for cell scattering and branching morphogenesis. This event regulates cofilin-dependent actin dynamics, impacting cell motility and tissue development.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Dynamic actin cytoskeleton remodeling is vital for cell functions like migration.
  • Tyrosine kinase activity influences cytoskeletal dynamics.
  • Annexin A2 (AnxA2) is a key protein involved in actin binding.

Purpose of the Study:

  • To investigate the role of annexin A2 (AnxA2) phosphorylation in cell scattering and branching morphogenesis.
  • To elucidate the molecular mechanisms linking AnxA2 phosphorylation to actin cytoskeletal regulation.

Main Methods:

  • Phosphotyrosine proteomic screening to identify AnxA2 phosphorylation sites.
  • Expression of AnxA2 mutants (Y23E, Y23A) in MDCK cells.
  • Short hairpin RNA (shRNA) mediated knockdown of AnxA2.
  • Analysis of cell scattering, 3D branching morphogenesis, and cofilin activity.

Main Results:

  • AnxA2 phosphorylation at Tyr23 (Y23E mutant) induced actin reorganization and cell scattering.
  • AnxA2 knockdown inhibited Src- and HGF-induced cell scattering and lumen formation.
  • Y23E-AnxA2 promoted HGF-independent branching morphogenesis.
  • Y23E-AnxA2-induced scattering correlated with cofilin dephosphorylation/activation.

Conclusions:

  • AnxA2 phosphorylation at Tyr23 is essential for regulating cofilin-dependent actin dynamics.
  • AnxA2 plays a critical role in cell scattering and branching morphogenesis.
  • AnxA2 is a key mediator of tyrosine kinase-regulated cytoskeletal rearrangements.

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