Regensburg 2010 – scientific programme

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BP: Fachverband Biologische Physik

BP 5: Posters: Biopolymers and Biomaterials

BP 5.12: Poster

Monday, March 22, 2010, 17:15–20:00, Poster B1

Entropy assists cell's contraction — •Carsten Schuldt and Josef Käs — Universität Leipzig, Germany

Cell migration is an inherent quality of life. Considering the motility of cells the current model is based on three constitutive processes: first, cytoskeletal extension at the leading edge; second, adhesion to the envirnonment to convey traction; and third, retraction at the rear. Polymerization of the cytoskeletal scaffold accounts for the extension and transmembrane proteins facilitate traction. The process of retraction is still debated.

Muscle-like actomyosin contractions were supposed to accomplish back retraction, originally. But myosin knock-out cells were still capable to migrate [1]. Alternatively, the depolymerization of cytoskeleton was proposed to cause contractile forces only by a gain in entropy in the absence of molecular motors. This concept was demonstrated on polymer meshworks of nematode's major sperm protein [2].

We intend to probe these forces in bundles of actin, which is one of the principal components of cytoskeletal biopolymer networks using optical tweezers.

[1]De Lozanne et. al., Science 236(4805)

[2]Wolgemuth et. al., Biophys. J. 88(4)