Reading the patterns in living cells -: the physics of Ca2+ signaling

Ca2+ is one of the most important messengers. It transmits signals inside living cells and takes part in intercellular coordination. The dynamics of the Ca2+ concentration shows a transition from elemental, stochastic events to global events like waves and oscillations. This transition renders it an ideal tool for studying basic concepts of pattern formation, especially since access to the most important experimental parameters is given. Ca2+ dynamics in living cells has been a major topic of biophysical modelling in the last 15 years. Modelling has reached the level of predictive power. The theoretical analysis of waves provided new insight into the mechanisms of Ca2+ signaling and led to new concepts of analysis of wave equations with concentration dependent diffusion and novel wave bifurcations. Modelling of oscillations provided understanding especially of complex oscillations and allowed to extract information about the underlying cellular parameters and mechanisms. The investigation of the stochastic aspects of intracellular Ca2+ dynamics demonstrated the fundamental role of fluctuations arising from the control of the release channel by Ca2+ and IP3. This review presents an overview of current theoretical research on Ca2+ dynamics in living cells driven by the inositol 1,4,5-trisphosphate receptor channel.