Berlin 2018 – scientific programme
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BP: Fachverband Biologische Physik
BP 6: Cytoskeletal Filaments I
BP 6.5: Talk
Monday, March 12, 2018, 16:15–16:30, H 1058
Stress-Strain Behavior of Vimentin Intermediate Filaments — Johanna Block1, Hannes Witt2, Andreas Janshoff2, Sarah Köster1, and •Anna Schepers1 — 1Institute for X-Ray Physics, University of Goettingen, 37077 Göttingen, Germany — 2Institute of Physical Chemistry, University of Goettingen, 37077 Göttingen, Germany
It is widely accepted that the cytoskeleton, which is composed of three filamentous protein structures - microfilaments (MFs), microtubules (MTs) and intermediate filaments (IFs) - plays a major role for cell mechanics. Whereas MFs and MTs are conserved between cell types, at least 70 different genes in humans code for IFs, which are expressed in a cell type specific manner. So far, it was not possible to infer the mechanical properties found on length scales of protein superstructure, cells and beyond, from the peculiar molecular architecture of IFs. Using optical tweezers, combined with microfluidics and fluorescence microscopy, we directly probed the stress-strain behavior of single vimentin IFs under physiological buffer conditions in a highly controlled fashion. We found a strong loading-rate dependent behavior, indicating that vimentin IFs act as a "safety belt" for cells. Further, our results provide evidence that single vimentin IFs act as an intracellular shock absorber using a balance of classical energy dissipation and storage of potential energy. By theoretical modelling and Monte Carlo simulations we are able to directly attribute filament mechanics to a molecular mechanism and reveal an intriguing non-equilibrium phenomenon leading to pronounced energy dissipation and mechanical adaption.