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BP: Fachverband Biologische Physik

BP 9: Regulation and Signaling

BP 9.6: Vortrag

Dienstag, 27. März 2007, 11:30–11:45, H43

Ca²⁺ signaling: order from disorder — •Alexander Skupin and Martin Falcke — Hahn-Meitner-Institut, Glienicker Str. 100, 14109 Berlin

In the last years, the understanding of the influence and importance of noise in biological systems has substantially increased. Here we show how microscopic fluctuations, i.e. the stochastic manner of ion channels, effect the global behavior of cells. Therfore we present biological experiments which have been done and analyzed in a physical way to characterize the underlying stochastic process and to show the importance of noise. We have measured oscillations of the cytosolic Ca²⁺ concentration in different cell types under different conditions. These oscillations are caused by the stochastic opening of ion channels releasing Ca²⁺ from internal stores into the cytosol. This liberated Ca²⁺ can activate adjoining channels resulting in a global Ca²⁺ wave within the cell. We analyzed the periods of these oscillations and the influence of Ca²⁺ buffer to specify the stochastic mechanism. It turns out that cells use array enhanced coherence resonance to create the wide spectrum of observed Ca²⁺ oscillations. Thus we demonstrate a first exampale of the constructive role of noise in cell signalling.