Microtubules soften due to cross-sectional flattening

Abstract
Data availability
Article and author information
Metrics

Abstract

We use optical trapping to continuously bend an isolated microtubule while simultaneously measuring the applied force and the resulting filament strain, thus allowing us to determine its elastic properties over a wide range of applied strains. We find that, while in the low-strain regime, microtubules may be quantitatively described in terms of the classical Euler-Bernoulli elastic filament, above a critical strain they deviate from this simple elastic model, showing a softening response with increasing deformations. A three-dimensional thin-shell model, in which the increased mechanical compliance is caused by flattening and eventual buckling of the filament cross-section, captures this softening effect in the high strain regime and yields quantitative values of the effective mechanical properties of microtubules. Our results demonstrate that properties of microtubules are highly dependent on the magnitude of the applied strain and offer a new interpretation for the large variety in microtubule mechanical data measured by different methods.

Data availability

Source data has been provided for Figure 6 along with source code files. Source code files have been provided for Figure 2 along with instructions for generating the data.

The following previously published data sets were used

1. Hawkins T
2. Mirigian M
3. Yasar MS
4. Ross JL
(2010) Flexural Rigidity of Single Microtubules.
NA.

https://www-sciencedirect-com.ezp-prod1.hul.harvard.edu/science/article/pii/S0021929009004965#tbl1

Article and author information

Author details

Edvin Memet

Department of Physics, Harvard University, Cambridge, United States

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-9414-597X
Feodor Hilitsk

Department of Physics, Brandeis University, Waltham, United States

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-5629-1407
Margaret A Morris

Department of Physics, Brandeis University, Waltham, United States

Competing interests
The authors declare that no competing interests exist.
Walter J Schwenger

Department of Physics, Brandeis University, Waltham, United States

Competing interests
The authors declare that no competing interests exist.
Zvonimir Dogic

Department of Physics, University of California, Santa Barbara, Santa Barbara, United States

Competing interests
The authors declare that no competing interests exist.
L Mahadevan

Department of Physics, Harvard University, Cambridge, United States

For correspondence
lm@seas.harvard.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-5114-0519

Funding

U.S. Department of Energy (DE-SC0010432TDD)

Feodor Hilitsk
Zvonimir Dogic

National Science Foundation (NSF-MCB-1329623)

Zvonimir Dogic

National Science Foundation (NSF- -CMMI-1068566)

Zvonimir Dogic

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.