Regensburg 2007 – scientific programme

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BP: Fachverband Biologische Physik

BP 9: Regulation and Signaling

BP 9.4: Talk

Tuesday, March 27, 2007, 11:00–11:15, H43

Yeast cell cycle: Stable network dynamics despite molecular fluctuations — •Stefan Braunewell and Stefan Bornholdt — Institute for Theoretical Physics, University of Bremen, Otto-Hahn-Allee, 28359 Bremen

Regulatory systems in living cells consist of many components, which interact through intricate cascades of molecular processes. In spite of the stochastic nature of these processes, a robust functioning of the regulatory machinery is required for the survival of the cell. On the basis of the model organism S. cerevisiae, we investigate the stability of the network dynamics under such noisy conditions [1]. We extend a recently proposed synchronous Boolean model of the yeast cell-cycle control network [2] to continuous time and allow for stochastic noise on the signal transmission times. Further we incorporate a low-pass filter to account for typical characteristics of transcriptional regulation. As a result, one finds that the cell-cycle network shows a remarkable stability against timing fluctuations and exhibits specific features that aid this stability.

[1] S. Braunewell and S. Bornholdt, Superstablity of the yeast cell cycle dynamics: Ensuring causality in the presence of biochemical stochasticity, J. Theor. Biol. (2006), doi:10.1016/j.jtbi.2006.11.012

[2] F. Li et al., The yeast cell-cycle network is robustly designed. Proc. Natl. Acad. Sci. USA (2004), 101(14):4781-4786