Regensburg 2013 – wissenschaftliches Programm

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PV: Plenarvorträge

PV IX

PV IX: Plenarvortrag

Mittwoch, 13. März 2013, 08:30–09:15, H1

Mechanics and dynamics of rapid cell movement — •Julie Theriot — Stanford University School of Medicine, Stanford, CA, USA

Directed, purposeful movement is one of the properties most closely associated with living organisms. At the cellular level, rapid crawling movements of cells as diverse as soil amoeba and human white blood cells depend on coordination of multiple dynamic elements over a wide range of distance and time scales. Using isolated fish skin cells called keratocytes as a model system, we have developed a biologically realistic force-based physical model for whole-cell motility that links molecular mechanisms to overall cell shape and speed. Under normal conditions, motile keratocytes assume a simple fan-like shape, and can move persistently with nearly constant shape and speed. Persistent steady-state motility involves the balanced interaction of forces generated by actin filament assembly and disassembly, myosin-based network contraction and demolition, cell-substrate adhesion, membrane tension, and hydrostatic pressure within the cell. Dramatic departures from steady-state movement can be induced in keratocytes by environmental perturbations, including alteration of substrate adhesivity and exposure of cells to electric fields. Quantitative comparison of cellular responses to these perturbations with the predictions of the physical model has enabled us to extend the model to encompass complex cell behaviors in changing conditions. Some features of the motile behavior of cells with more complicated shapes, including human white blood cells, can also be explained within the same mechanical framework.