Regensburg 2013 – scientific programme

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BP: Fachverband Biologische Physik

BP 12: Molecular Motors

BP 12.1: Invited Talk

Tuesday, March 12, 2013, 09:30–10:00, H43

Motor and Track Systems for Navigating the Cytoskeleton — Joanna Kalita^1,2 and •Ronald Rock¹ — ¹The University of Chicago, Chicago, USA — ²University of Wrocław, Wrocław, Poland

An emerging paradigm in motility is the notion of "specialized" motors, or motors that are fine-tuned to perform a specific function. Rather than merely traveling anywhere and everywhere, such motors are programmed to select certain tracks, to respond to forces in a defined way, or to actively remodel their tracks. Here, we further develop the ex vivo motility assay to determine how cells remodel their actin tracks and redirect myosin V traffic in response to Rho GTPase signaling. We transfected 3T3 cells with constitutively active or dominant negative forms of Rac1, RhoA, or CDC42, triton extracted the cells to expose the cytoskeletons, and applied labeled myosin V for single molecule tracking. We find that all Rho constructs increase myosin V activity. Remarkably, only a small fraction of actin filaments are used by myosin V, as we find that motors repeatedly travel in limited zones while ignoring nearby regions of high actin density.