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Microtubule treadmilling in vivo
1Laboratory of Molecular Biology, University of Wisconsin, Madison, WI 53706, USA. ggborisy@facstaf.wisc.edu
Science (New York, N.Y.)
|January 10, 1997
Summary
Cytoplasmic microtubules detach from centrosomes and depolymerize from their minus ends. This suggests a minus-end mechanism for microtubule turnover and movement, challenging existing dynamic instability models.
Area of Science:
- Cell Biology
- Cytoskeletal Dynamics
Background:
- Cytoplasmic microtubules are crucial for cellular structure and transport.
- Microtubule turnover is traditionally explained by dynamic instability at plus ends.
- Centrosomes nucleate and anchor microtubule minus ends.
Purpose of the Study:
- To investigate microtubule detachment and depolymerization mechanisms.
- To explore alternative models for microtubule turnover in vivo.
- To understand the role of centrosomes in microtubule dynamics.
Main Methods:
- Observation of microtubule behavior in cytoplasmic fragments of fish melanophores.
- Analysis of microtubule detachment from nucleation sites.
- Tracking of free microtubule movement and depolymerization.
Main Results:
- Microtubules were observed to detach from their nucleation sites at the centrosome.
- Depolymerization occurred from the minus ends of detached microtubules.
- Free microtubules exhibited treadmilling, with growth at one end and shortening at the other.
Conclusions:
- Microtubule detachment from centrosomes may be a common occurrence.
- A minus-end depolymerization mechanism for microtubule turnover is proposed.
- This challenges the prevailing plus-end dynamic instability model and supports treadmilling.