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BP: Fachverband Biologische Physik
BP 30: Posters: Physics of Cells
BP 30.13: Poster
Thursday, March 17, 2011, 17:15–20:00, P3
Establishment of Cell Polarity in Yeast Saccharomyces cerevisiae — •Ben Klünder1, Tina Freisinger2, Jared L. Johnson3, Roland Wedlich-Söldner2, and Erwin Frey1 — 1Department of Physics, Ludwig-Maximilians-Universität München, Theresienstraße 37, D-80333 München, Germany — 2Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany — 3Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
Cell polarization is a prerequisite for processes such as cell motility, proliferation, and stem cell differentiation. The yeast Saccharomyces cerevisiae is able to polarize spontaneously in the absence of spatial cues and without help of cytoskeletal structures. The emergence of polarity instead was found to rely on a network of regulatory proteins of the central polarity GTPase Cdc42. However, the fundamental mechanisms for polarity establishment still remain to be identified. Based on new experimental findings we propose a minimal model of cell polarization which uses local self-amplification of activation and recruitment of Cdc42 to establish a stable cap of Cdc42 on the plasma membrane. Using a combination of analytical and numerical methods we study the effect of mutations in Cdc42 regulators, which lead to either loss of polarization or characteristic changes of experimentally accessible observables. Our results are consistent with measurements from in vivo studies and indicate that cell polarization of yeast depends on self-enhanced recruitment of Cdc42 coupled to rapid cycling of GTPase activity.