Lateral diffusion of receptor-ligand bonds in membrane adhesion zones: Effect of thermal membrane roughnessH. Krobath1, 2, G. J. Schütz2, R. Lipowsky1 and T. R. Weikl1
1 Max Planck Institute of Colloids and Interfaces - 14424 Potsdam, Germany
2 University Linz - Altenbergerstr. 69, 4040 Linz, Austria
received 23 November 2006; accepted in final form 18 March 2007; published May 2007
published online 17 April 2007
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.
87.16.Dg - Membranes, bilayers, and vesicles.
87.15.Vv - Diffusion.
68.35.Np - Adhesion.
© Europhysics Letters Association 2007