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ASAP, a human microtubule-associated protein required for bipolar spindle assembly and cytokinesis

Jean-Michel Saffin1, Magali Venoux, Claude Prigent

  • 1Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Unité Propre de Recherche 1142, Rue de la Cardonille, 34396 Montpellier Cédex 5, France.

Proceedings of the National Academy of Sciences of the United States of America
|July 29, 2005
PubMed

Insights

We discovered ASter-Associated Protein (ASAP), a microtubule-associated protein crucial for cell division. ASAP ensures proper spindle assembly, mitosis progression, and cytokinesis, preventing severe mitotic defects and cell death.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Protein Function

Background:

  • Microtubule-associated proteins (MAPs) play vital roles in microtubule dynamics and organization.
  • Proper regulation of the mitotic spindle is essential for accurate chromosome segregation and cell division.

Purpose of the Study:

  • To identify and characterize a novel human microtubule-associated protein (MAP).
  • To elucidate the function of this protein, named ASter-Associated Protein (ASAP), in mitosis and cytokinesis.

Main Methods:

  • Immunofluorescence microscopy to determine ASAP localization during the cell cycle.
  • Biochemical assays to confirm direct binding to microtubules.
  • Overexpression and RNA interference (RNAi) to study ASAP's functional impact.
  • Analysis of mitotic spindle organization and progression.

Main Results:

  • ASAP localizes to microtubules in interphase, the mitotic spindle during mitosis, and the central body during cytokinesis.
  • ASAP directly binds to microtubules via its COOH-terminal domain.
  • ASAP overexpression causes microtubule bundling and aberrant monopolar spindles.
  • ASAP depletion leads to defective mitotic spindles, delayed mitosis, and failed cytokinesis.

Conclusions:

  • ASAP is a key factor for proper spindle assembly.
  • ASAP plays a crucial role in regulating mitosis progression and cytokinesis.
  • The findings define ASAP as a critical protein for maintaining genomic stability and cell viability.

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