Force fluctuations and polymerization dynamics of intracellular microtubules
- 9 October 2007
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 104 (41), 16128-16133
- https://doi.org/10.1073/pnas.0703094104
Abstract
Microtubules are highly dynamic biopolymer filaments involved in a wide variety of biological processes including cell division, migration, and intracellular transport. Microtubules are very rigid and form a stiff structural scaffold that resists deformation. However, despite their rigidity, inside of cells they typically exhibit significant bends on all length scales. Here, we investigate the origin of these bends using a Fourier analysis approach to quantify their length and time dependence. We show that, in cultured animal cells, bending is suppressed by the surrounding elastic cytoskeleton, and even large intracellular forces only cause significant bending fluctuations on short length scales. However, these lateral bending fluctuations also naturally cause fluctuations in the orientation of the microtubule tip. During growth, these tip fluctuations lead to microtubule bends that are frozen-in by the surrounding elastic network. This results in a persistent random walk of the microtubule, with a small apparent persistence length of ≈30 μm, ≈100 times smaller than that resulting from thermal fluctuations alone. Thus, large nonthermal forces govern the growth of microtubules and can explain the highly curved shapes observed in the microtubule cytoskeleton of living cells.Keywords
This publication has 21 references indexed in Scilit:
- Bending Dynamics of Fluctuating Biopolymers Probed by Automated High-Resolution Filament TrackingBiophysical Journal, 2007
- Microtubules can bear enhanced compressive loads in living cells because of lateral reinforcementThe Journal of cell biology, 2006
- Cytoskeletal remodelling and slow dynamics in the living cellNature Materials, 2005
- Microrheology, Stress Fluctuations, and Active Behavior of Living CellsPhysical Review Letters, 2003
- Dynamics and mechanics of the microtubule plus endNature, 2003
- Actomyosin-based Retrograde Flow of Microtubules in the Lamella of Migrating Epithelial Cells Influences Microtubule Dynamic Instability and Turnover and Is Associated with Microtubule Breakage and TreadmillingThe Journal of cell biology, 1997
- Domains of Neuronal Microtubule-associated Proteins and Flexural Rigidity of MicrotubulesThe Journal of cell biology, 1997
- Methods of Digital Video Microscopy for Colloidal StudiesJournal of Colloid and Interface Science, 1996
- Beyond self-assembly: From microtubules to morphogenesisCell, 1986
- Microtubule dynamics in interphase cells.The Journal of cell biology, 1986