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Preparation of Segmented Microtubules to Study Motions Driven by the Disassembling Microtubule Ends
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A novel homo-oligomeric protein responsible for an MPF-dependent microtubule-severing activity

N Shiina1, Y Gotoh, E Nishida

  • 1Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.

The EMBO Journal
|December 1, 1992
PubMed

Insights

Researchers identified a novel protein that severs microtubules, activated by maturation-promoting factor (MPF). This discovery sheds light on cell cycle-dependent microtubule organization changes.

Area of Science:

  • Cell Biology
  • Molecular Biology

Background:

  • Microtubule-severing activity was previously observed in M phase extracts but not interphase extracts of Xenopus eggs.
  • Maturation-promoting factor (MPF) is a key regulator of cell cycle progression.

Purpose of the Study:

  • To identify and purify the protein responsible for MPF-dependent microtubule-severing activity in Xenopus egg extracts.
  • To characterize the structure and function of this novel microtubule-severing factor.

Main Methods:

  • Incubation of interphase extracts with purified MPF.
  • Purification of the microtubule-severing factor.
  • Biochemical characterization of the purified factor's activity, binding properties, and structure.

Main Results:

  • Incubation with MPF rapidly increased microtubule-severing activity in interphase extracts.
  • A novel homo-oligomeric protein factor composed of 56 kDa subunits was identified and purified.
  • The factor has a doughnut-shaped structure, severs microtubules independently of ATP and divalent cations, and binds to both tubulin and microtubules.
  • Activity is inhibited by monomeric tubulin.

Conclusions:

  • A novel microtubule-binding protein with unique structural and functional properties has been identified.
  • This protein mediates MPF-dependent microtubule severing and may be crucial for cell cycle-dependent changes in microtubule organization.

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