Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 3: Statistical Physics of Biological Systems I (joint DY/BP/CPP)

BP 3.6: Talk

Monday, March 16, 2015, 11:15–11:30, BH-N 243

Lateral domain formation in membranes coupled to curvature — •Sina Sadeghi, Marcus Müller, and Richard Vink — Institute of Theoretical Physics, Georg-August-Universität Göttingen, Göttingen, Germany

The lateral heterogeneity in the plasma membrane of eukaryotic cells is an important factor for regulating biological functions. As opposed to plasma membranes, model membranes (either artificially prepared membranes, or membranes extracted from living cells) typically phase separate. To address this paradox, we present computer simulations of a coarse-grained membrane model that undergoes macroscopic phase separation at low temperature. Considering a coupling between local composition and local curvature of the membrane, we show that the system exhibits composition fluctuations with a nontrivial length scale, resembling microemulsion. The latter is identified as a region where lipid rafts can form. We furthermore probe the nature of phase transition between the phase-separating regime and the mixed state. This transition is continuous and belongs to the two-dimensional Ising universality class for weak coupling to curvature, but becomes first-order for strong curvature-composition coupling.