Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 26: From Single-Molecule to Tissue Dynamics

BP 26.6: Vortrag

Donnerstag, 25. März 2010, 15:30–15:45, H43

Cargo transport by molecular motors against shear flow — •Fridtjof Kowald^1,2, Christian Korn³, and Ulrich Schwarz^2,3 — ¹Karlsruhe Institute of Technology, Theoretical Biophysics Group — ²University of Heidelberg, Institute for Theoretical Physics — ³University of Heidelberg, Bioquant

Processive molecular motors like kinesins transport cellular cargo like vesicles, organelles, nuclei or viruses along cytoskeletal tracks like microtubules. In a physiological context, the motors usually work in groups. This allows them to stay attached to the filament for a long time and to produce high levels of force. There are several sources for opposing forces which disrupt cargo transport, including viscous forces on the moving cargo, forces from motors pulling in other directions, forces from the interaction of the cargo with other cellular structures, and shear forces due to hydrodynamic flow in the environment. Here we address the latter case using computer simulations for adhesive motor dynamics. Our Langevin equation includes hydrodynamic interactions of the spherical cargo with the wall and the shear flow, rupture and rebinding of the motor connections to the filament, and motor stepping with a linear force-velocity relation. Our main result is the distribution of unbinding times as a function of motor number and shear rate. This allows us to predict how the critical shear flow for non-productive transport increases as a function of motor number. We comment on possible applications of our results to cellular systems and in nanobiotechnology.