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BP: Fachverband Biologische Physik

BP 19: Biological Membranes II

BP 19.4: Talk

Tuesday, March 15, 2011, 14:45–15:00, ZEU 260

Chemical oscillations in cell membranes — •Chris Händel¹, Undine Dietrich², Sergio Alonso³, Markus Bär⁴, and Josef Käs⁵ — ¹Division of Soft Matter Physics, University of Leipzig, Germany — ²Division of Soft Matter Physics, University of Leipzig, Germany — ³Physikalisch-Technische Bundesanstalt, Berlin, Germany — ⁴Physikalisch-Technische Bundesanstalt, Berlin, Germany — ⁵Division of Soft Matter Physics, University of Leipzig, Germany

The MARCKS protein is an actin filament cross-linking protein which has relevant functions in different organisms. It is located at the plasma membrane and interacts via electrostatic forces with PIP2 containing cell membranes. In a model membrane, designed by a mixed DPPC/PIP2- monolayer, the binding of MARCKS peptide to the membrane increases the lateral pressure. The unbinding dynamics modulated by PKC generates a reaction-diffusion system. This leads to oscillations of the lateral pressure which can be attributed to changes in the liquid condensed domain size. An adequate and sensitive tool for monitoring these oscillations is the Langmuir trough technique combined with a film balance. The present work confirms the theoretical calculations of this reaction-diffusion system by using model membranes. These calculations describe the dynamic distribution of acidic lipids in response to cytosolic proteins and regulating enzymes. We obtained oscillations in lateral pressure and analyzed the images of the domains depending on the lateral pressure. Furthermore, our results indicate that the oscillations correlate with changes in shape and size of the domains.