Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 36: Cell adhesion, mechanics and migration II

BP 36.3: Talk

Wednesday, March 18, 2015, 15:30–15:45, H 1058

Experimental Exploration of the Phase Space of Actin Waves — •Erik Bernitt, Malte Ohmstede, and Hans-Günther Döbereiner — Institut für Biophysik, Universität Bremen, Bremen, Germany

We study actin waves in fibroblast cells that noticeably undulate the cell surface forming Circular Dorsal Ruffles (CDRs). We are interested in the currently unknown mechanism underlying these waves. Previous research in our lab revealed that the cell shape strongly influences the wave dynamics of CDRs, which complicated an analysis of the wave mechanism due to the irregular morphology of fibroblasts. When forced into a well-defined, disk-like morphology, however, cells form waves in a highly regular manner allowing detailed studies of the wave mechanism. We place these cells in flow channels allowing for rapid switching of the cellular biochemical state.

We ask which active role actin plays in the propagation mechanism of CDRs. From the behavior in the phase space of theoretical models, we expect that the amount of free g-actin plays a pivotal role. Our setup gives us access to this phase space experimentally. With our approach, experimental and theoretical data can easily be matched, because CDRs on disc-shaped cells propagate laterally between cell edge and nucleus, forming an effectively one-dimensional system with periodic boundary conditions. Here we report our latest experiments in which we shift the cell's position of the chemical equilibrium between f- and g-actin using latrunculin A.