Dresden 2009 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 19: Cell Adhesion

BP 19.1: Vortrag

Donnerstag, 26. März 2009, 10:45–11:00, ZEU 260

Modelling the active mechanical response of stress fibers — •Achim Besser and Ulrich S. Schwarz — University of Karlsruhe, Theoretical Biophysics Group, Kaiserstrasse 12, 76131 Karlsruhe, Germany

Stress fibers are bundles of actin filaments held together by the crosslinker protein α-actinin and actively tensed by the molecular motor protein myosin II. We have developed a model that describes stress fiber dynamics after biochemical or mechanical perturbations. For example, our stress fiber model can be solved analytically for the contraction dynamics after severing the fiber at any point along its length. Experimentally this situation has been realized by laser cutting and our model has been applied to analyze such data. The model equations can also be solved analytically for the case of cyclic boundary forces yielding theoretical predictions for the frequency dependence of the complex modulus of stress fibers. Decomposing it into its real and imaginary parts and using model parameters determined from the laser cutting experiments, we arrive at estimates for the storage and loss moduli. These quantities could be measured in future experiments and then would provide an additional test for our model.