Related Experiment Videos
Structure of growing microtubule ends: two-dimensional sheets close into tubes at variable rates
D Chrétien1, S D Fuller, E Karsenti
1European Molecular Biology Laboratory, Heidelberg, Germany.
The Journal of Cell Biology
|June 1, 1995
Summary
Microtubule growth rates vary due to tubulin sheet length and cylinder closure dynamics. Conformational changes in tubulin molecules drive both microtubule assembly and disassembly processes.
Area of Science:
- Biochemistry
- Cell Biology
- Structural Biology
Background:
- Microtubules are dynamic polymers essential for cellular processes.
- Understanding microtubule assembly and disassembly mechanisms is crucial for cell biology.
- Previous studies have observed variable microtubule growth rates.
Purpose of the Study:
- To investigate the structural basis of variable microtubule growth rates.
- To elucidate the role of tubulin conformation in microtubule dynamics.
- To develop a model explaining microtubule assembly and disassembly.
Main Methods:
- Cryo-electron microscopy to visualize microtubule ends.
- Analysis of tubulin sheet length and curvature.
- Video microscopy to observe growth rate variations.
Main Results:
- Microtubule ends exhibit diverse structures, from blunt to curved sheets.
- Mean sheet length correlates with growth rate; distribution width with assembly extent.
- A model incorporating variable cylinder closure rates explains observed growth rate variability.
Conclusions:
- Tubulin sheet length and variable cylinder closure rates dictate microtubule growth variability.
- Conformational changes in tubulin molecules occur during assembly and disassembly.
- These findings provide insights into the fundamental mechanisms of microtubule dynamics.