Regensburg 2010 – scientific programme
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BP: Fachverband Biologische Physik
BP 32: Posters: Physics of Cells
BP 32.28: Poster
Thursday, March 25, 2010, 17:15–20:00, Poster B1
Confined Intermediate Filament Fluctuations in Live Cells — •Jannick Langfahl-Klabes1, Jens Nolting1, Alexander Egner2, and Sarah Köster1 — 1Courant Research Centre Nano-Spectroscopy and X-Ray Imaging, University of Göttingen, Germany — 2Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
The cytoskeleton, which provides mechanical strength for the cell, contains three different types of fibrous proteins. Besides actin and microtubules intermediate filaments (IFs) play an important role. IFs are extremely flexible biopolymers that can be stretched to several times their initial length. The key to these large deformations is their hierarchical structure, which facilitates cascaded deformation mechanisms at different levels of strain. The filamentous structures in live cells are by no means static but undergo excessive fluctuations and show dynamics on many different time scales. We investigate keratin intermediate filament networks which are believed to play a key role in cell mechanics. To this end we carry out time-lapse fluorescent live cell imaging experiments on genetically enhanced carcinoma cells. These model cells express fluorescent keratin which forms thick cytoplasmic bundles. We perform fluctuation analyses based on the worm-like-chain model to investigate the influence of thermal versus active motion and retrieve mechanical properties like persistence length and bending rigidity. Our results show that keratin bundles are strongly confined within the surrounding network. This observation is further confirmed by a structural analysis using high-resolution STED microscopy.