Issue
EPL
Volume 78, Number 3, May 2007
Article Number 38003
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/78/38003
Published online 17 April 2007
EPL, 78 (2007) 38003
DOI: 10.1209/0295-5075/78/38003

Lateral diffusion of receptor-ligand bonds in membrane adhesion zones: Effect of thermal membrane roughness

H. 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

Abstract
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.

PACS
87.16.Dg - Membranes, bilayers, and vesicles.
87.15.Vv - Diffusion.
68.35.Np - Adhesion.

© Europhysics Letters Association 2007