Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 25: Cell Mechanics I

AKB 25.1: Talk

Thursday, March 30, 2006, 15:00–15:15, ZEU 260

F-actin bundle mechanical properties — •Mark Bathe¹, Mireille Claessens², Claus Heussinger¹, Andreas Bausch², and Erwin Frey¹ — ¹Ludwig-Maximilians-Universitaet Muenchen — ²Technische Universitaet Muenchen

Animal cells express a myriad of actin-binding proteins (ABPs) that associate with Filamentous actin (F-actin) to form stiff bundles in vivo. The physiological function of F-actin bundles varies from passive mechanical structures such as microvilli present on the surface of epithelial cells in the intestinal lining to active structures such as filopodia formed at the leading edge of cells during migration.

A biomimetic emulsion technique, recently introduced by our lab, has been used to measure directly the bending stiffness of isolated F-actin bundles associated with biologically-relevant ABPs. Results demonstrate that bundle stiffness depends sensitively on the number of actin filaments constituting the bundle, bundle length, and ABP type and concentration. Here, we use a combination of molecular simulation and analytical theory to elucidate the origin of the observed bundle mechanical properties. We also determine for the first time the molecular stiffnesses of the various ABPs examined.