Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 5: Posters: Biopolymers and Biomaterials

BP 5.20: Poster

Montag, 22. März 2010, 17:15–20:00, Poster B1

Active growth of actin filaments can lead to a non-exponential length distribution — •Christoph Erlenkämper and Karsten Kruse — Theoretische Physik, Universität des Saarlandes, 66123 Saarbrücken, Germany

Important properties of the actin cytoskeleton depend on the distribution of actin filament lengths. Here, we study the growth dynamics of actin filaments, taking into account addition and removal of monomers at both ends, the different phosphorylation states of the monomers and a stochastic dephosphorylation of monomers within the filaments [1,2]. The assembly of actin is active: While energy-rich ATP-bound actin monomers are readily integrated into filaments, the dephosphorylated ADP-actin monomers only have a low affinity for the filament and easily detach from it. In contrast to unregulated filament growth, we find that the active growth can lead to non-exponential length distributions. We show that they result from a stability gradient of monomers within a treadmilling filament. This is similar to a possible mechanism of length regulation by destabilizing proteins [3].

[1] Bindschadler et al, Biophys. J. 86 (2004) 2720.

[2] Stukalin and Kolomeisky, Biophys. J. 90 (2006) 2673.

[3] Erlenkämper and Kruse, Phys. Biol. 6 (2009) 046016.