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Opposite-end behaviour of dynamic microtubules
S R Martin1, M J Schilstra, P M Bayley
1Division of Physical Biochemistry, National Institute for Medical Research, Mill Hill, London, U.K.
Biochimica Et Biophysica Acta
|April 9, 1991
Summary
Microtubules exhibit distinct dynamic behaviors at their two ends due to inherent structural asymmetry. This study unifies their treatment, revealing how subunit interactions control microtubule dynamics.
Area of Science:
- Biophysics
- Cell Biology
- Structural Biology
Background:
- Microtubules are essential cytoskeletal polymers with inherent polarity.
- Dynamic instability governs microtubule growth and shrinkage.
- Asymmetry in microtubule lattice affects subunit addition and hydrolysis kinetics differently at each end.
Purpose of the Study:
- To present a unified mathematical model for microtubule dynamics at both polar ends.
- To investigate how subunit interactions influence the kinetic properties of microtubule ends.
- To explore the mechanisms controlling microtubule dynamic instability.
Main Methods:
- Application of the Lateral Cap formulation principles.
- Development of a unified theoretical treatment for microtubule dynamic instability.
- Analysis of tubulin-GTP addition and hydrolysis kinetics.
Main Results:
- The model predicts significantly different dynamic properties (growth/shrinkage amplitudes and lifetimes) for the two microtubule ends.
- The differences in dynamics depend on the coupling of tubulin-GTP hydrolysis via longitudinal and lateral contacts.
- Subunit-subunit interactions at microtubule ends are key determinants of kinetic behavior.
Conclusions:
- A unified model explains the asymmetric dynamics of microtubules.
- Fine details of subunit interactions can dictate the distinct kinetic behaviors of microtubule ends.
- This provides a potential mechanism for controlling microtubule dynamics in vitro and in vivo.