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Analysis of cortical flow models in vivo
H A Benink1, C A Mandato, W M Bement
1Department of Zoology, University of Wisconsin, Madison 53706, USA.
Molecular Biology of the Cell
|August 10, 2000
Summary
Microtubules suppress cellular cortical flow by inhibiting actin cytoskeleton contraction. Localized manipulation reveals that microtubules control flow direction by regulating actomyosin-based contraction, impacting cell motility.
Area of Science:
- Cell Biology
- Cytoskeletal Dynamics
- Cell Motility
Background:
- Cortical flow, the directed movement of F-actin and organelles, is crucial for cell motility.
- The role of microtubules in directing cortical flow, specifically whether they stimulate or inhibit actin cytoskeleton contraction, remains debated.
Purpose of the Study:
- To elucidate the mechanism by which microtubules suppress cortical flow.
- To investigate if microtubules can control the direction of cortical flow through localized manipulation.
Main Methods:
- Xenopus oocytes treated with phorbol 12-myristate 13-acetate (PMA) to induce cortical flow.
- Localized application of PMA and experimental displacement of the germinal vesicle (microtubule organizing center).
- Time-lapse confocal microscopy and photobleaching to observe F-actin dynamics.
Main Results:
- Localized PMA application redirected cortical flow towards the stimulus site.
- Microtubule depolymerization accelerated redirected cortical flow, indicating suppression is direction-independent.
- Cortical flow is driven by F-actin network contraction, which microtubules inhibit.
Conclusions:
- Cortical flow is directed towards areas of localized F-actin cytoskeleton contraction.
- Microtubules suppress cortical flow by inhibiting actomyosin-based contraction.
- Microtubule-dependent regulation of contraction controls the direction of cortical flow.