Berlin 2008 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 8: Active Filament Networks
BP 8.8: Vortrag
Dienstag, 26. Februar 2008, 12:00–12:15, C 243
Viscoelastic Actin Bundles — •Dan Strehle1, José Alvarado1, Brian Gentry1, Lukas Hild1, Mark Bathe2,3, Erwin Frey2, and Josef Käs1 — 1Universität Leipzig — 2LMU München — 3C.N.R.S. Gif-sur-Yvette
Bundles of actin perform a number of important functions in cells. As stress fibers they play a crucial role in biopolymer networks constituting the cytoskeleton, in filopodia they probe the extracellular environment, in acrosomal processes of sperm cells they perforate the membrane of the egg, whereas in stereocilia they serve as signal transducing organelles of hair cells.
For these various tasks cells are able to finely tune the mechanical properties of bundles by determining their thickness and choosing from a variety of actin bundling proteins. Dynamic crosslinkers, for instance, create the possibility for a viscoelastic-like response to different stresses encountered in cellular conditions.
We are actively probing the mechanical properties of actin bundles using optical tweezers. Upon applying stress, a timescale-dependent novel behavior, plastic deformation, is observed, shedding light on the internal structure and kinetics of the bundles. Using this method, properties of bundles formed with different bundling proteins can be compared.
Elucidating the mechanical behavior of bundles might also provide additional insight into the viscoelastic response of biopolymer networks.