Elastic response, buckling, and instability of microtubules under radial indentation

Iwan A. T. Schaap, Carolina Carrasco, Pedro J. de Pablo, Frederick C. MacKintosh, Christoph F. Schmidt

Research output: Contribution to journalArticlepeer-review

133 Citations (Scopus)

Abstract

We tested the mechanical properties of single microtubules by lateral indentation with the tip of an atomic force microscope. Indentations up to similar to 3.6 nm, i.e., 15% of the microtubule diameter, resulted in an approximately linear elastic response, and indentations were reversible without hysteresis. At an indentation force of around 0.3 nN we observed an instability corresponding to an similar to 1-nm indentation step in the taxol-stabilized microtubules, which could be due to partial or complete rupture of a relatively small number of lateral or axial tubulin-tubulin bonds. These indentations were reversible with hysteresis when the tip was retracted and no trace of damage was observed in subsequent high-resolution images. Higher forces caused substantial damage to the microtubules, which either led to depolymerization or, occasionally, to slowly reannealing holes in the microtubule wall. We modeled the experimental results using finite-element methods and find that the simple assumption of a homogeneous isotropic material, albeit structured with the characteristic proto. lament corrugations, is sufficient to explain the linear elastic response of microtubules.

Original languageEnglish
Pages (from-to)1521-1531
Number of pages11
JournalBiophysical Journal
Volume91
Issue number4
DOIs
Publication statusPublished - 15 Aug 2006

Keywords

  • SCANNING FORCE MICROSCOPY
  • FLEXURAL RIGIDITY
  • TUBULIN
  • PROTOFILAMENTS
  • RESOLUTION
  • LATTICE
  • MODEL

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