Dresden 2006 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 5: Cell Motility II
AKB 5.5: Vortrag
Montag, 27. März 2006, 15:15–15:30, ZEU 255
Protrusion Forces Driving Rapidly Translocating Cells — •Michael Goegler1, Claudia Brunner1, Allen Ehrlicher1, Bernd Kohlstrunk1, Detlef Knebel2, and Josef Käs1 — 1Institute for Soft Matter Physics, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany — 2JPK Instruments AG, Bouchéstrasse 12, 12435 Berlin, Germany
Cell motility is a fundamental process of many phenomena in nature, such as immune response, wound healing, and metastasis. Mechanisms of force generation for cell migration have been described in various hypotheses requiring actin polymerization and/or molecular motors, but quantitative force measurements to date have focused on traction forces. Here we present a direct measurement of the forward force generated at the leading edge of the lamellipodium and at the cell body of a translocating fish keratocyte. We positioned an elastic spring, the cantilever of a scanning force microscope (SFM), in front of a moving cell, which pushed the cantilever out of its path. The forward force was calculated using the detected vertical deflection of the cantilever in an No-dqelastic wedge modelNo-dq, which considers cellular deformation. We measured forward forces between 1-8 nN without visibly affecting the cells. At stronger opposing forces up to at least 15 nN the lamellipodium of the cell retracted locally whereas the overall movement of the cell remained unaffected. Measurements with steadily increasing applied force were carried out to determine a load dependence behaviour. We investigated the effect of cytochalasin D in force measurements to elucidate the importance of actin polymerization in cellular protrusion.