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Control of Aurora-A stability through interaction with TPX2

Maria Giubettini1, Italia A Asteriti, Jacopo Scrofani

  • 1Institute of Molecular Biology and Pathology, CNR, c/o Sapienza University of Rome, Via degli Apuli 4, 00185, Rome, Italy.

Journal of Cell Science
|December 15, 2010
PubMed

Insights

The microtubule-binding protein TPX2 protects Aurora-A kinase from degradation throughout the cell cycle in human cells. This novel role of TPX2 is crucial for maintaining Aurora-A stability and function.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Aurora-A kinase is essential for spindle assembly and function.
  • Aurora-A is frequently overexpressed in tumors and its levels are cell cycle-regulated.
  • The microtubule-binding protein TPX2 regulates Aurora-A activity and localization during mitosis.

Purpose of the Study:

  • To investigate a novel regulatory role of TPX2 in controlling Aurora-A stability.
  • To determine how TPX2 influences Aurora-A degradation in human cells.
  • To elucidate the mechanism by which TPX2 affects Aurora-A protein levels.

Main Methods:

  • RNA interference (siRNA) to silence TPX2 expression.
  • Overexpression of TPX2 domains to study Aurora-A degradation.
  • Assessment of Aurora-A protein levels in different cell cycle phases.
  • Investigation of proteasome activity and APC/C-Cdh1 involvement.

Main Results:

  • TPX2 silencing led to decreased Aurora-A levels in G2 and prometaphase cells.
  • Overexpression of the TPX2 Aurora-A-binding region impaired Aurora-A degradation in telophase.
  • Aurora-A degradation in TPX2-silenced cells required proteasome activity and APC/C-Cdh1.
  • Restoration of Aurora-A levels was dependent on the Aurora-A-binding capacity of TPX2.

Conclusions:

  • TPX2 plays a novel role in protecting Aurora-A from degradation in both interphase and mitosis.
  • This stabilization mechanism is independent of TPX2's known functions in spindle assembly and Aurora-A activation.
  • TPX2 is a key regulator of Aurora-A stability, impacting its abundance in human cells.

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