Berlin 2008 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 7: Posters I
BP 7.40: Poster
Montag, 25. Februar 2008, 17:00–19:30, Poster A
Lateral diffusion of receptor-ligand bonds in membrane adhesion zones: Effect of thermal membrane roughness — •Heinrich Krobath1, Gerhard Schütz2, Reinhard Lipowsky1, and Thomas Weikl1 — 1Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Wissenschaftspark, D-14476 Potsdam-Golm — 2Johannes-Kepler-Universität Linz, Institut für Biophysik, A-4040 Linz
The adhesion of cells is mediated by membrane receptors that bind to complementary ligands in apposing cell membranes. It is generally assumed that the lateral diffusion of mobile receptor-ligand bonds in membrane-membrane adhesion zones is slower than the diffusion of unbound receptors and ligands. We find that this slowing-down is not only caused by the larger size of the bound receptor-ligand complexes, but also by thermal fluctuations of the membrane shape. We model two adhering membranes as elastic sheets pinned together by receptor-ligand bonds and study the diffusion of the bonds using Monte Carlo simulations. In our model, the fluctuations reduce the bond diffusion constant in planar membranes by a factor close to 2 in the biologically relevant regime of small bond concentrations.