Regensburg 2007 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 15: Biopolymer Solutions and Networks

BP 15.3: Vortrag

Dienstag, 27. März 2007, 15:45–16:00, H44

Dynamic Properties of individual F-Actin Filaments in 3D Networks — •masashi degawa, bernd hoffmann, rudolf merkel, and margret giesen — Forschungszentrum Juelich IBN4, 52425 Juelich Germany

The rigidity and dynamical properties of the cell cytoskeleton are determined by a 3D network of polymerized one-dimensional protein filaments, one of which is the actin filament (F-actin). The understanding of the thermodynamics of F-actin filaments is crucial for cell biophysics, specially within such a network. Whereas isolated F-actin is well described by the worm-like chain model [1], knowledge of thermodynamic properties of F-actin in networks is still scarce. Here we present first studies of F-actin within a 3D network where the presence of other filaments serves as an entropic constraint. We used partially TRITC-labeled networks of different concentration. The fluctuations of the labeled filaments were visualized with line-scan confocal scanning microscopy time images with a time resolution of 1 ms. We measure the time dependence of the filament fluctuations, which yield a concentration dependence of the crossover time in the time correlation function from isolated to constrained behavior of the individual F-actin. [1] L. Le Goff, O. Hallatschek, E. Frey, F. Amblard, Phys. Rev. Lett. 89, 258101 (2002)