Dresden 2006 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 21: Intracellular Transport

AKB 21.1: Vortrag

Donnerstag, 30. März 2006, 10:45–11:00, ZEU 260

A stochastic model for intra-cellular transport of single-headed molecular motors — •Andreas Schadschneider¹, Philip Greulich¹, Katsuhiro Nishinari², Yasushi Okada³, and Debashish Chowdhury⁴ — ¹Institut für Theoretische Physik, Universität zu Köln, 50937 Köln — ²Department of Aeronautics and Astronautics, University of Tokyo, Japan — ³Department of Cell Biology and Anatomy, University of Tokyo, Japan — ⁴Department of Physics, Indian Institute of Technology, Kanpur, India

Motivated by recent experiments on KIF1A, a representative member of single-headed kinesin motor proteins family, we develop a theoretical model of intra-cellular transport by mutually interacting molecular motors. It explicitly accounts not only for the hydrolysis of ATP, but also for the ratchet mechanism which is believed to drive each individual KIF1A motor. We study the model by a combination of analytical and numerical techniques. A remarkable feature is that all parameters can be completely determined from experimental data. Our results in the dilute limit are in excellent quantitative agreement with the empirical data from single molecule experiments. In the high density regime the predictions of the model also agree qualitatively with the corresponding experimental observations. We derive a phase diagram that shows the influence of hydrolysis and Langmuir kinetics on the collective spatio-temporal organization of the motors. Finally, we provide experimental evidence for the existence of domain walls in our in-vitro experiment with fluorescently labeled KIF1A; these domain walls correspond to the shocks observed in the density profiles of our theoretical model.