Regensburg 2022 – scientific programme

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BP: Fachverband Biologische Physik

BP 17: Membranes and Vesicles

BP 17.5: Talk

Wednesday, September 7, 2022, 16:15–16:30, H13

Asymmetric membranes, chemical potentials and homeostasis — •Martin Girard — Max-Planck-Institut für Polymerforschung

The properties of membranes in cells are tightly regulated. For instance, Sineski clearly established that E. Coli cells maintain a viscosity of around 2 poise, which is achieved by modulating the chemical composition of the membrane. How cells choose to alter this composition is not obvious, and has been associated with various controversies over the years.

I have recently introduced usage of chemical potential in computer simulations as a proxy for membrane homeostasis in cells. In coarse-grained simulations, this results in surprisingly good agreement between trends measured in cells and simulation results. I have also shown that this model can be used as a proxy for flippase proteins, and thus enables simulations of asymmetric membranes. Using this model, I will show that imposing asymmetries in membranes can result in surprising behavior. For example, that cholesterol concentration can become correlated with the presence of unsaturated lipids, in accord with experimental measurements. I will discuss the biological implications of these results.