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BP: Fachverband Biologische Physik
BP 26: Posters: Membranes and Vesicles
BP 26.24: Poster
Donnerstag, 29. März 2012, 17:30–19:30, Poster A
Nonlinear pattern formation in biomimetic membranes — •Chris Händel1, Bernd Käßemodel1, Undine Dietrich1, Sergio Alonso2, Markus Bär2, and Josef Käs1 — 1Division of Soft Matter Physics, Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstraße 5, 04103 Leipzig , Germany — 2Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
The MARCKS (Myristoylated alanine-rich C kinase substrate) protein is an actin filament cross-linking protein which reveals relevant functions in different organisms. It is located at the plasma membrane and interacts via electrostatic forces with the membran lipid PIP2 (1,2- Dipalmitoylphosphatidylinositol 4,5-diphosphate). In a biomimetic membrane, designed by a mixed DPPC/PIP2- monolayer, binding of MARCKS peptide to the membrane increases the lateral pressure, whereas unbinding dynamics modulated by PKC (Protein kinase C) generates a nonlinear reaction-diffusion system. This mechanism leads to oscillations of the lateral pressure which can be correlated to changes in the ratio of ordered and disordered phase in the membrane. Employing a theoretical model, we could calculate the dynamic distribution of acidic lipids in response to cytosolic proteins and regulating enzymes. The present work confirms these theoretical assumptions of this reaction-diffusion system by using model membranes. We obtained oscillations in lateral monolayer pressure which correlate with changes in shape and size of the crystalline lipid domains and the ratio of the area requirement of the liquid and the crystalline phase of the monolayer.