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Updated: Aug 7, 2026

Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis
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Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis

Published on: December 5, 2017

Control of the AtMAP65-1 interaction with microtubules through the cell cycle

Andrei P Smertenko1, Hsin-Yu Chang, Seiji Sonobe

  • 1The Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, South Road, Durham, DH1 3LE, UK.

Journal of Cell Science
|July 19, 2006
PubMed

Insights

Microtubule bundling protein MAP65-1 (AtMAP65-1) activity is regulated by phosphorylation during cell division. This phosphorylation is crucial for proper spindle organization and timely progression through mitosis.

Area of Science:

  • Plant cell biology
  • Molecular and cell biology
  • Biochemistry

Background:

  • Cell division relies on precise control of microtubule dynamics and organization.
  • Microtubule-associated protein MAP65 is vital for anaphase spindle integrity and cell division.
  • Arabidopsis thaliana MAP65-1 (AtMAP65-1) bundles microtubules, forming 25 nm cross-bridges, and its activity varies across the cell cycle.

Purpose of the Study:

  • To investigate the cell cycle-dependent regulation of AtMAP65-1 activity.
  • To identify the molecular mechanisms controlling AtMAP65-1 function during mitosis.
  • To determine the impact of AtMAP65-1 phosphorylation on mitotic progression and spindle organization.

Main Methods:

  • Analysis of AtMAP65-1 phosphorylation status during different cell cycle stages.
  • Investigating the roles of Cyclin-Dependent Kinase (CDK) and Mitogen-Activated Protein Kinase (MAPK) in AtMAP65-1 phosphorylation.
  • Expressing non-phosphorylatable AtMAP65-1 mutants to assess their effects on mitosis.

Main Results:

  • AtMAP65-1 undergoes hyperphosphorylation during prometaphase and metaphase.
  • CDK and MAPK pathways are involved in the phosphorylation of AtMAP65-1.
  • Phosphorylation inhibits AtMAP65-1's microtubule bundling activity.
  • Expression of non-phosphorylatable AtMAP65-1 leads to excessive microtubule accumulation and delayed mitosis.

Conclusions:

  • Mitotic progression and metaphase spindle organization are dependent on the inactivation of AtMAP65-1.
  • Phosphorylation serves as a key regulatory mechanism to control AtMAP65-1 activity during cell division.
  • Understanding AtMAP65-1 regulation provides insights into the fundamental processes of cell division in plants.

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