Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 10: Postersession II

BP 10.14: Poster

Montag, 12. März 2018, 17:30–19:30, Poster C

How filaments density impacts force generation and protrusion rate of lamellipodium in motile cells — •Setareh Dolati and Martin Falcke — Max delbrück center for molecular medicine(MDC), Berlin, Germany.

In Migrating cells, the Arp2/3-complex is thought to be responsible for formation and maintenance of the lamellipodium. However, studies show in addition to Arp2/3 activity formins also contribute to actin filament nucleation and elongation in the lamellipodium of B16-F1 melanoma cells and their activity strongly impacts force generation. Loss of formins reduces actin density, lamellipodium width and protrusion velocity of B16-F1 melanoma cells, while Arp2/3 activity and the actin network assembly rate are not affected by the absence of formins. Knocking out FMNL2 and FMNL3 individually and both together shows a correlation between actin filament area density and protrusion rates. Also, by manipulating Arp2/3 activity in B16-F1 melanoma cells, the same correlation between the protrusion rate and the filament area density in the lamellipodium has been observed.

Here, we mathematically model the lamellipodium as a viscoelastic gel representing an actively polymerizing and cross linked network of actin filaments. Taking the density of filaments as a control parameter, we suggest a mechanism that explains how the formins contribution to the actin area density leads to their corresponding contribution to the protrusion rate in the lamellipodium and how the structure of the actin network and properties like assembly rate of the network affect the dynamics of the lamellipodium.