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The actin-bundling protein palladin is an Akt1-specific substrate that regulates breast cancer cell migration

Y Rebecca Chin1, Alex Toker

  • 1Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.

Molecular Cell
|May 18, 2010
PubMed

Insights

Scientists discovered palladin, an actin-associated protein, is phosphorylated by Akt1, inhibiting breast cancer cell migration. This finding clarifies Akt isoform roles in cancer metastasis and identifies a new therapeutic target.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Biology

Background:

  • The phosphatidylinositol 3-kinase (PI3K) pathway is often dysregulated in cancer.
  • Akt1 and Akt2 kinases downstream of PI3K play contrasting roles in breast cancer cell invasion and metastasis.

Purpose of the Study:

  • To identify substrates of Akt isoforms involved in breast cancer cell migration.
  • To elucidate the role of palladin in Akt-mediated regulation of cell motility.

Main Methods:

  • Western blotting to detect phosphorylation.
  • Cell migration and invasion assays.
  • 3D cell culture for morphogenesis studies.
  • Immunofluorescence to visualize F-actin.

Main Results:

  • Palladin was identified as an Akt1-specific substrate, phosphorylated at Ser507.
  • Akt1-mediated phosphorylation of palladin inhibits breast cancer cell migration and invasion.
  • Palladin phosphorylation is essential for F-actin bundling and maintaining cytoskeletal organization.
  • Downregulation of palladin promotes cell migration and invasion, and abnormal branching morphogenesis.

Conclusions:

  • Palladin is a key Akt1 substrate regulating breast cancer cell motility.
  • Akt1 phosphorylation of palladin inhibits migration by promoting F-actin bundling and cytoskeletal organization.
  • This study reveals a molecular mechanism for the distinct functions of Akt1 and Akt2 in breast cancer metastasis.

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