Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 7: Poster I

BP 7.12: Poster

Monday, March 23, 2009, 17:45–20:00, P3

Dynamics of formin promoted actin polymerization — •Carsten Schuldt, Brian Gentry, Dan Strehle, and Josef A. Käs — Universität Leipzig, Germany

In vivo the semiflexible polymer actin is found as a single filament or is organized in networks and bundles. These structures contribute to the cytoskeleton, whose inherent properties determine the cell's morphology, both mechanically and functionally, and facilitate motility via protrusions and contractions. The assembly of some cytoskeletal actin bundles (contractile ring, filopodia) far from thermodynamic equilibrium is driven by a multi-domain protein called formin. This 'leaky capper' is known to remain bound to the growing ends of filaments and is capable of accelerating the polymerization rate.

We employ an optical tweezer setup in interaction with functionalized microbeads to measure formin's stall force and step size in vitro. Determinig the stall force will yield further insight into formin's ability to produce forces from biochemical energy. In particular, formin may be able to override the force limit of normal actin polymerization. The application of the sophisticated force clamp technique seems to be an apropriate technique to measure step size and examine the behavior of formin with and without external applied tension.