Dresden 2011 – scientific programme

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BP: Fachverband Biologische Physik

BP 22: Physics of Cells I

BP 22.7: Talk

Wednesday, March 16, 2011, 17:00–17:15, ZEU 250

Actin network growth in the tail of small propelled particles — •Julian Weichsel and Ulrich S. Schwarz — ITP and Bioquant, University of Heidelberg

In the lamellipodium of migrating animal cells, the growth of the actin network against the plasma membrane generates the work required to push the cell envelope forward. The same mechanism is exploited by pathogens like the Listeria bacterium and the Vaccinia virus as they propel themselves forward in the cytoplasm of the infected host cell. In fact even plastic beads, vesicles or oil droplets can be propelled in this way in in-vitro assays. We have shown before with stochastic network simulations and a rate equation theory that the steady state structure of the growing actin network in the lamellipodium can dramatically change as a function of network growth velocity [1]. Here we extend this description to curved obstacles in a piecewise-linear approximation in two dimensions. By using adequately rotated reference frames, we again find similar transitions in the actin network behind small propelled particles.

[1] Weichsel, J., and Schwarz, U. S. Two competing orientation patterns explain experimentally observed anomalies in growing actin networks. PNAS 107, 14 (2010), 6304--6309.