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Laura Schaedel

Self-repair rejuvenates mechanically stressed microtubules

Published on 1 July 2016

Thesis presented July 01, 2016

Microtubules play an important role in many cellular functions. They can be highly bent by intracellular forces, yet how mechanical stress affects microtubules and how they tolerate the vast forces exerted on them remains unknown. In this thesis, the effect of mechanical stress on microtubule mechanical properties is studied. It is found that the stiffness of microtubules decreases when they are exposed to repeated bending forces, revealing that they are subject to material fatigue. Pre-existing defects in the lattice seem to be present weak points in the microtubules, where mechanical stresses concentrate and generate more extensive damage.
Interestingly, microtubules are able to recover their initial stiffness while incorporating new tubulin dimers from the solution into their lattice, demonstrating their self-healing properties. It also shows that microtubule dynamics is not exclusive to the plus and minus ends of microtubules, challenging established paradigms.
Tubulin dimers that are incorporated into the microtubule lattice are GTP bound. GTP tubulin is known to be more stably bound in the lattice, and is thought to promote microtubule rescue. Indeed, this thesis shows that tubulin incorporation into the lattice far from the tip in response to microtubule damage can lead to rescue events. This finding opens up a new perspective on an aspect of microtubule dynamic instability that so far is poorly understood.

Self-repair, microtubules, microfluidic, mechanical stress

Download this thesis.