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Pom1 kinase links division plane position to cell polarity by regulating Mid1p cortical distribution

Séverine Celton-Morizur1, Victor Racine, Jean-Baptiste Sibarita

  • 1Institut Curie, Centre de Recherche and CNRS UMR144, Paris, France.

Journal of Cell Science
|November 2, 2006
PubMed

Insights

Fission yeast Pom1 kinase regulates the positioning of Mid1p, a protein crucial for cell division. This regulation links cell polarity to the division plane, ensuring proper cell division.

Area of Science:

  • Cell biology
  • Molecular biology
  • Genetics

Background:

  • Mid1p is essential for determining the cell division plane in fission yeast.
  • Mid1p localizes to the medial cortex, recruiting myosin II for contractile ring assembly.
  • The mechanism restricting Mid1p to the medial cortex was previously unknown.

Purpose of the Study:

  • To investigate how Mid1p localization is regulated in fission yeast.
  • To understand the role of cell polarity regulators in Mid1p distribution.
  • To link cell polarity mechanisms to the establishment of the division plane.

Main Methods:

  • Analysis of Mid1p distribution in pom1 and bud6Delta fission yeast mutants.
  • Investigating the effect of monopolar growth on Mid1p localization.
  • Assessing the role of Pom1 kinase in regulating Mid1p distribution.

Main Results:

  • In pom1 mutants with monopolar growth, Mid1p distribution expanded to the non-growing tip, uncoupling it from nuclear position.
  • This misdistribution in pom1 mutants led to contractile ring displacement.
  • Mid1p localization remained normal in bud6Delta mutants, indicating misdistribution is not a general effect of monopolar growth.

Conclusions:

  • Pom1 kinase negatively regulates Mid1p distribution, excluding it from non-growing cell ends.
  • A separate, Pom1-independent mechanism prevents Mid1p association with growing cell ends.
  • Cell polarity regulators, like Pom1, influence Mid1p distribution, thereby connecting cell polarity to division plane positioning.

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