Dresden 2009 – scientific programme

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SYDI: Symposium SKM Dissertation Prize 2009

SYDI 1: SKM Dissertation Prize 2009

SYDI 1.3: Talk

Monday, March 23, 2009, 11:30–12:00, BAR SCHÖ

Model Systems of the Actin Cortex — •Oliver Lieleg — Lehrstuhl E27 für Zellbiophysik, Physik-Department, TU München, 85748 Garching, Germany — FAS Center for Systems Biology, Harvard University, Cambridge, USA

The cytoskeleton is constituted by networks of cross-linked and bundled biopolymers. While microtubuli serve as tracks for transport processes, the actin cortex mainly determines the mechanical properties of cells. However, due to the biological complexity of the cytoskeleton, it is difficult to unravel the microscopic principles which guide its viscoelastic response. Only in well-defined model systems the contribution of physical and biochemical parameters can be disentangled. In this talk I demonstrate that the microstructure of actin networks crucially depends on both the type and density of actin cross-linking proteins. This network microstructure sets the local deformation mode and with that the macroscopic elasticity of the network. Transient binding events between cross-linked actin filaments limit the stability of actin networks under mechanical load and dictate the viscoelastic network properties at low frequencies. Thus, the microscopic interaction potential between actin filaments and cross-linking proteins can be determined from the macroscopic frequency response of cross-linked actin networks. My results highlight how cells can harness a few generic physical principles in order to achieve enormous mechanical versatility.