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Published on: November 9, 2017
A novel mitosis-specific dynamic actin structure in Dictyostelium cells
1Department of Biology, Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan.
Journal of Cell Science
|November 22, 2007
Summary
Dictyostelium cells lacking type II myosin can divide without a contractile ring by utilizing novel actin structures called mitosis-specific dynamic actin structures (MiDASes). These MiDASes act as crucial attachment sites, enabling substratum-dependent cell division.
Area of Science:
- Cell Biology
- Cytoskeletal Dynamics
- Biophysics
Background:
- Cell division in many animal cells requires attachment to a substratum.
- Dictyostelium cells lacking type II myosin exhibit unusual substratum-dependent division without a contractile ring.
Purpose of the Study:
- To elucidate the mechanism of substratum-dependent cytokinesis in Dictyostelium cells lacking type II myosin.
- To investigate the role of novel actin structures during mitosis.
Main Methods:
- Confocal and total internal reflection fluorescence microscopy to observe actin dynamics.
- Microtubule inhibition experiments.
- Fluorescence recovery after photobleaching.
- Interference reflection microscopy and jet stream assays.
Main Results:
- Discovery of mitosis-specific dynamic actin structures (MiDASes) in the ventral cortex during mitosis.
- MiDASes split with the nucleus and associate with astral microtubules.
- MiDASes are essential for substratum attachment and their disruption by microtubule inhibitors aborts cytokinesis.
- MiDASes are highly dynamic, dot-like actin structures and serve as major cell attachment sites.
Conclusions:
- MiDASes are novel actin scaffolds essential for substratum-dependent cytokinesis in Dictyostelium.
- Astral microtubules are required for MiDAS formation and maintenance.
- MiDASes facilitate the transmission of mechanical force to the substratum, enabling cell division without a contractile ring.
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