Berlin 2012 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 27: Posters: Cytoskeletal Filaments

BP 27.2: Poster

Donnerstag, 29. März 2012, 17:30–19:30, Poster A

Molecular motors can sharpen the length distribution of treadmilling filaments — •Denis Johann, Christoph Erlenkämper, and Karsten Kruse — Theoretische Physik, Universität des Saarlandes, Postfach 151150, 66041 Saarbrücken, Germany

The assembly of actin filaments and microtubules depends on the hydrolysis of nucleotide tri-phostohates. Together with their structural polarity this can lead to treadmilling, a process during which the filaments, on average, grow at one end and shrink at the other. The distribution of proteins binding to a treadmilling filament increases towards the shrinking end. For proteins affecting the removal rate of filament subunits such a gradient implies an effectively length-dependent depolymerization rate, which can lead to a unimodal length distribution unknown to polymers at equilibrium [1]. Using Monte-Carlo simulations, we show that the width of the length distribution can narrow substantially if the depolymerizing proteins are molecular motors, moving directionally towards the shrinking end. We present expressions for the width of the length distribution in the limits of vanishing and infinite motor speeds.

[ 1] C. Erlenkämper, K. Kruse, Phys. Biol. 6, 046016 (2009)