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The origin of phragmoplast asymmetry
Andrei P Smertenko1, Bernard Piette, Patrick J Hussey
1School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, UK.
Current Biology : CB
|November 15, 2011
Summary
Plant cell division relies on the phragmoplast, a structure that guides vesicles to form a new cell plate. Our study reveals microtubules within the phragmoplast exhibit dynamic instability, not treadmilling, enabling directional vesicle transport.
Area of Science:
- Plant Cell Biology
- Cytokinesis Research
- Microtubule Dynamics
Background:
- The phragmoplast is crucial for plant cytokinesis, directing vesicle transport to the cell plate.
- Dysfunctional phragmoplasts lead to developmental defects, embryo lethality, or multinucleate cells.
- Existing models propose microtubule treadmilling maintains phragmoplast asymmetry for vesicular traffic.
Purpose of the Study:
- To investigate microtubule behavior within the plant phragmoplast.
- To challenge the prevailing model of microtubule treadmilling in phragmoplast asymmetry.
- To propose a new model integrating microtubule dynamics and phragmoplast function.
Main Methods:
- Live-cell imaging of plant cells.
- Mathematical modeling of microtubule behavior.
- Dynamic simulations of phragmoplast assembly.
Main Results:
- Microtubules in the phragmoplast initiate randomly.
- Most microtubules display dynamic instability, with increased turnover near the midzone.
- Directional vesicle transport is facilitated by microtubules polymerizing towards the midzone.
Conclusions:
- The established model of microtubule treadmilling is insufficient to explain phragmoplast asymmetry.
- A novel model incorporating microtubule dynamic instability and polymerization directionality is proposed.
- This inclusive model reconciles microtubule dynamics with protein activity in phragmoplast assembly.
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