Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 27: Posters: Cytoskeletal Filaments

BP 27.14: Poster

Thursday, March 29, 2012, 17:30–19:30, Poster A

Contractile force generation by entropic softening of actin networks — •Carsten Schuldt, Tom Golde, and Josef Käs — Universität Leipzig

One major constituent of the cell's cytoskeleton is the globular protein actin, organized in filaments subjected to steady assembly and disassembly. We study the depolymerization of actin bundles of cross-linked single actin filaments and networks. In particular, the forces associated with this process are of interest.

Retraction at the rear of a cell is a fundamental part of its migration process. This contraction can be accomplished by actin-myosin interaction. However, myosin knock-out cells have been shown to be still capable of migrating. Alternatively, the depolymerization of the cytoskeleton was proposed to cause contractile forces only by a gain in entropy in the absence of molecular motors. This concept has been demonstrated on polymer meshworks of nematode's major sperm protein [1].

We employ a microrheology approach in conjunction with severing proteins to measure both softening and contraction of the depolymerizing network.

[1] Wohlgemuth et al., Biophys. J, 88, 2462 (2005)