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AKB: Biologische Physik

AKB 14: Molecular Motors

AKB 14.5: Talk

Tuesday, March 28, 2006, 17:15–17:30, ZEU 255

Force dependence of motor protein mediated filament depolymerisation — •Gernot Klein, Karsten Kruse, and Frank Jülicher — Max Planck Institute for the Physics of Complex Systems Nöthnitzerstr. 38 01187 Dresden

Many active processes in cells are driven by highly specialised motor proteins, which interact with filaments of the cytoskeleton. Members of the KIN-13 kinesin subfamily are able to induce depolymerisation of the filaments ends[1]. In the mitotic spindle, certain members of the KIN-13 subfamily, which are linked to chromosomes, facilitate pole ward-movement of chromosomes by depolymerising spindle microtubules. In this situation, motors are mechanically coupled and remove subunits under the influence of external forces. Recently we have developed a general description of motor protein induced filament depolymerisation[2]. Based on this description, we study the collective behaviour of depolymerising motor proteins, which are mechanically linked to a common anchoring point, e.g. a bead, and examine the influence of an externally-applied force on motor-induced filament depolymerisation. We find that the depolymerisation velocity can increase as well as decrease for an increasing external force before motors detach from the filament. This behaviour depends on the processivity of the motors during depolymerisation. We compare results obtained in mean-field description with discrete stochastic simulations. The situation studied in our work could be realised by in vitro experiments in which KIN-13 family members are attached to a bead and interact with a filament end. [1] A.W. Hunter, et al., Mol. Cell 11, 445 (2003) [2] G.A. Klein, et al. Phys.Rev.Lett. 94, 108102 (2005)