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Updated: May 20, 2026
10:52
Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets
Published on: August 13, 2016
The functional antagonism between Eg5 and dynein in spindle bipolarization is not compatible with a simple push-pull
Stefan Florian1, Thomas U Mayer
1Department of Biology and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.
Cell Reports
|July 27, 2012
Summary
Dynein and Eg5 motor proteins do not directly oppose each other during cell division. Live imaging shows dynein likely antagonizes Eg5 indirectly, challenging previous assumptions about spindle pole separation.
Area of Science:
- Cell Biology
- Molecular Motors
- Cytoskeleton Dynamics
Background:
- Eg5 motor protein drives mitotic spindle pole separation by crosslinking antiparallel microtubules.
- Dynein has been hypothesized to directly antagonize Eg5 at the spindle equator, promoting spindle collapse.
Purpose of the Study:
- To investigate the antagonistic relationship between Eg5 and dynein during mitosis.
- To determine if endpoint quantifications accurately reflect spindle dynamics or are misleading.
Main Methods:
- Development of a mathematical model to analyze spindle phenotypes.
- Proof-of-principle experiments using live-cell imaging.
- Depletion of dynein and its binding protein Lis1 in the presence of an Eg5 inhibitor.
Main Results:
- Endpoint quantifications can overestimate defective phenotypes, making them potentially misleading.
- Live-cell imaging revealed that dynein and Eg5 activities are not simply titratable against each other.
- Spindle formation is possible even with Eg5 inhibition when dynein or Lis1 is depleted.
Conclusions:
- The direct push-pull antagonism model between dynein and Eg5 at the spindle equator is likely incorrect.
- Dynein most likely antagonizes Eg5 indirectly by exerting forces at different spindle locations.
- Rethinking the mechanisms of spindle pole separation and the roles of microtubule-based motors is necessary.
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