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AKB: Biologische Physik
AKB 14: Molecular Motors
AKB 14.8: Talk
Tuesday, March 28, 2006, 18:00–18:15, ZEU 255
The interplay between crosslinkers and dynamic molecular motor-induced instabilities in the moderation of biopolymer organization — •David Smith1,2, David Humphrey2, Falko Ziebert3, Walter Zimmermann3, and Josef Käs1,2 — 1Institute for Soft Matter Physics, Universität Leipzig, Linné Str. 5, D-04103 Leipzig Deutschland — 2Center for Nonlinear Dynamics, University of Texas at Austin, Texas 78712, USA — 3Physikalisches Institut, Universität Bayreuth, D-95440 Bayreuth Deutschland
Structure and function of biological cells rely on the highly-dynamic self-organization of protein filaments to an intracellular cytoskeleton responsive to mechanical and chemical stimuli. While dissolving these complex cellular structures through Brownian motion is inherently slow (tens of minutes), changes in the activity of the molecular motor myosin II cause rapid order-disorder transitions within 1-2 minutes in reconstituted cytoskeletal actin networks. When motor-induced filament sliding decreases, actin network structure rapidly and reversibly self-organizes into various assemblies triggered by a nonlinear instability. Modulation of static crosslinker concentrations allow for a wide phase space of order ranging from nematics to compact asters & dense packing of motor-filament clusters. The observed isothermal transitions between disorder and self-organization illustrate that molecular motors can substantially contribute to dynamic cellular organization.