Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 14: Membranes and Vesicles
BP 14.8: Vortrag
Mittwoch, 28. März 2012, 11:45–12:00, H 1028
Dynamics of vesicle adhesion mediated by mobile lipid-anchored receptors and ligands — •Susanne F. Fenz1, Ana-Suncana Smith2, Rudolf Merkel3, and Kheya Sengupta4 — 1LION, Leiden University, The Netherlands — 2Institute of Theoretical Physics and Excellence Cluster, Engineering of advanced materials, University Erlangen-Nuernberg, Germany — 3Institute of Complex Systems 7, Research Centre Juelich, Germany — 4CNRS UPR 3118, Aix-Marseille Universite, France
Giant unilamellar vesicles (GUVs) adhering to supported lipid bilayers were used as a model system to mimic dynamics of receptor-ligand mediated cell-cell adhesion. We followed the adhesion process in real time by microinterferometry and determined the adhered area, as a function of time. The adhesion process exhibits three phases: nucleation, linear growth and saturation. We find that the onset of adhesion depends critically on the concentration of ligands in the GUV. The growth regime, on the other hand, is quite robust with respect to variations in receptor or ligand concentrations, but is conditioned by the tension in the GUV membrane. GUVs with a larger excess membrane area, exhibit higher fluctuations and form multiple nucleation centers while tense GUVs usually form only one nucleation center. Accordingly, the adhesion zone of tense GUVs grows slower. While the ligand concentration in the GUV membrane sets the timescale for the nucleation, the saturation time till a steady adhesion state is reached, depends on the receptor concentration on the bilayer. We give a qualitative discussion of these experimental results.