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BP: Fachverband Biologische Physik

BP 18: Membranes and vesicles I (joint BP/CPP)

BP 18.4: Vortrag

Dienstag, 17. März 2015, 10:30–10:45, H 1028

Mechanics of the cell membrane coupled to the actomyosin cortex — •Jochen A. M. Schneider and Guillaume Salbreux — Max Planck Institute for the Physics of Complex Systems, Dresden, Germany

The cell membrane is the outer layer of a biological cell. It consists of lipids which form a two-dimensional fluid bilayer structure and is attached via linker proteins to the underlying actomyosin cortex, a thin network of actin filaments and myosin motors. In the past years, research has mainly focused on the physical description of the cell membrane and cytoskeleton independently. However, little is known on how they mechanically interact in the cell.

Here, we present a model for the interaction of membrane and cytoskeleton based on the assumption that the anchored membrane is attached to the underlying actomyosin cortex, subjected to active tension arising from myosin activity. Cell pressure results in membrane protrusions which can equilibrate their surface tensions by exchange of lipids. Using this physical description, we characterize how excess membrane area distributes around the cell. Based on a few fundamental cell parameters, the cortex tension, the membrane bending stiffness and the anchoring strength, we find a phase diagram with regions corresponding to a homogeneous distribution of membrane, to the pulling of membrane tubes and to the formation of one or several blebs. We finally use this result to discuss potential consequences for the mechanics of the cell.