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BP: Fachverband Biologische Physik

BP 6: Statistical Physics of Biological Systems II (joint DY, BP)

BP 6.7: Talk

Monday, March 14, 2011, 15:45–16:00, HÜL 186

Explicit Expressions for the Mean First Passage Time of a Diffusing Molecule in Different Two-Dimensional Geometries — •Ronny Straube — Systems Biology Group, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany

The mean first passage time (MFPT) of a diffusing molecule is an important quantity that describes the first encounter between the molecule and a distant target site. For signaling molecules the MFPT can have a strong impact on the output of a signaling pathway and the inverse of the average MFPT can be used as the diffusion-limited association rate between the molecule and the target site. We have recently shown that in two dimensions the MFPT can be expressed in terms of an associated Neumann function [1] whose regular part can significantly contribute to the average MFPT. Here, I provide simple expressions for the average MFPT in different membrane patch geometries [2] including a square-shaped domain, a cylindrical domain and the surface of a sphere. I also discuss the impact of the presence of multiple target sites on the MFPT. These results can be used to estimate the average MFPT, the foward rate constant or the time scale of receptor clustering for biological membranes of various shapes.

[1] D. Coombs, R. Straube, M. J. Ward, SIAM J. Appl. Math. 70, 302–332 (2009). [2] F. Wei, D. Yang, R. Straube, J. Shuai, submitted to Phys. Rev. E