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Stefan Diez

Fast filament and protein dynamics in motile cells

Actin networks are continuously reorganized in cells capable of rapidly changing their shape. We apply total internal reflection fluorescence (TIRF) microscopy at acquisition rates of 10 to 20 Hz to live cells for visualizing the dynamics of filamentous actin structures throughout the entire substrate-attached cell cortex of Dictyostelium cells [1-3]. We propose that high turnover rates of actin filaments confer the plasticity to the cell cortex that is required for rapid accommodation to external stimuli.

Actin Network Dynamics Visualized by LimE-GFP (Red and Green Pseudocolors Represent Gain and Loss of Network Elements) [1]. Leading edges and foci of dense actin assemblies appear in yellow because of their high fluorescence intensities.


Collaboration with Kurt Anderson (now at the Beatson Institute for Cancer Research, Glasgow) and the research group of Günther Gerisch (MPI of Biochemistry, Martinsried).

We measured an average growth rate of 3 µm/sec for filamentous actin structures throughout the entire substrate-attached cortex of Dictyostelium cells [3].

References

[1] T. Bretschneider, S. Diez, K. Anderson, J. Heuser, M. Clarke, A. Müller-Taubenberger, J. Köhler, G. Gerisch
Dynamic Actin Patterns and Arp2/3 Assembly at the Substrate attached Surface of Motile Cells.
Current Biology, Vol. 14, 1-10, 2004

[2] G. Gerisch, T. Bretschneider, A. Müller-Taubenberger, E. Simmeth, M. Ecke, S. Diez, K. Anderson
Mobile actin clusters and traveling waves in cells recovering from actin depolymerization.
Biophys J. 2004 Nov;87(5):3493-503

[3] S. Diez, G. Gerisch, K. Anderson, A. Müller-Taubenberger, T. Bretschneider
Subsecond Reorganization of the Actin Network in Cell Motility and Chemotaxis.
Proc Natl Acad Sci USA, Vol. 102, no. 21, pp. 7601-6, 2005

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