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Dynein and mast/orbit/CLASP have antagonistic roles in regulating kinetochore-microtubule plus-end dynamics

Rita Reis1, Tália Feijão, Susana Gouveia

  • 1IBMC Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.

Journal of Cell Science
|June 25, 2009
PubMed

Insights

The microtubule plus-end tracking protein mast and cytoplasmic dynein have opposing roles in regulating mitotic spindle assembly. Their balance is crucial for maintaining spindle bipolarity and length during cell division.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Mitotic spindle establishment and maintenance depend on coordinated microtubule-associated proteins and motor activities.
  • The microtubule plus-end tracking protein Mast/Orbit/CLASP and cytoplasmic dynein are key regulators of spindle dynamics.

Purpose of the Study:

  • To investigate the roles of Mast/Orbit/CLASP and cytoplasmic dynein in mitotic spindle regulation.
  • To elucidate how these proteins influence microtubule dynamics at kinetochores during mitosis.

Main Methods:

  • Utilized Drosophila melanogaster embryos and S2 cells for experimental analysis.
  • Employing techniques to track Mast/Orbit/CLASP localization and co-depletion strategies for dynein.

Main Results:

  • Mast/Orbit/CLASP accumulates at kinetochores early in mitosis, then streams poleward upon microtubule attachment.
  • Cytoplasmic dynein mediates the reduction of Mast/Orbit/CLASP at kinetochores during metaphase and anaphase.
  • Co-depletion of dynein rescues spindle bipolarity and microtubule poleward flux in Mast/Orbit/CLASP-depleted cells.

Conclusions:

  • Mast/Orbit/CLASP and cytoplasmic dynein exhibit antagonistic functions in regulating microtubule plus-end dynamics at kinetochores.
  • This antagonistic interaction is vital for maintaining spindle bipolarity and proper spindle length during mitosis.

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