Berlin 2008 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 8: Active Filament Networks

BP 8.6: Vortrag

Dienstag, 26. Februar 2008, 11:30–11:45, C 243

A Mechanism of Filament Length Regulation — •Christoph Erlenkämper and Karsten Kruse — Universität des Saarlandes, Theoretische Physik, 66041 Saarbrücken, Germany

The cytoskeleton is a network of filamentous polymers, notably actin filaments and microtubules. It determines the mechanical properties of a cell and is involved in various vital cellular processes. An important characteristic of the cytoskeleton is the distribution of filament lenghts. In vitro filaments typically show an exponential length distribution, which can be explained by the intrinsic filament dynamics [1][2]. In cells, however, filament lengths are regulated by additional proteins. Here, we investigate a mechanism of length regulation by proteins which influence depolymerization at the ends of treadmilling filaments. It applies, for example, to ADF/cofilin which promotes subunit removal from the ends of actin filaments. We present stochastic simulations as well as an analytic calculation of the steady state distribution. In contrast to the in vitro situation, we find a distribution that is peaked around the average filament length.

[1] F. Oosawa and S. Asakura, “Thermodynamics of the Polymerization of Protein”, Academic Press, New York, 1975

[2] M. Dogterom and S. Leibler, PRL, 70 (1347), 1993