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W. G. Pritchard Lab Seminar: 4:30-5:30 PM, 320 Whitmore Laboratory

	            **Monday January 31, 2005**
	
Mechanisms of cell motion: dynamic networks and flexible membranes

Wolfgang Losert

Dept of Physics / Institute for Physical Science & Technology
University of Maryland


Abstract:

Motion of cells in response to external signals is crucial for many 
biological processes, from wound healing to the spread of cancer.  I will 
discuss two of the physical processes that can generate the forces needed 
for cell motion:  Dynamic changes in the scaffolding of filaments (actin, 
tubulin, and intermediate filaments) that give a cell mechanical strength, 
and deformations of cell membranes. I will introduce a toy model of 
dynamic self-assembling filaments that recovers the key properties of e.g. 
tubulin. Experimentally we use two photon confocal microscopy for 3D 
imaging and a holographic laser tweezer for multipoint mechanical 
measurements of both filament networks and membranes. Recent experiments 
indicate that spatial gradients in network properties can generate strong 
directional forces on objects embedded in the network.

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