Modeling the spatio-temporal organization of cytosolic Ca²⁺ in non-excitable cells

Geneviève Dupont*

Université Libre de Bruxelles, Brussels, Belgium

*gdupont@ulb.ac.be

Changes in the concentration of intracellular Ca²⁺ represent one of the most widespread and versatile signaling pathway. They mediate vital physiological responses such as secretion, gene expression or fertilization. In electrically non-excitable cells, these elevations of Ca²⁺ concentration are brought about by an increase of the widespread messenger InsP3 that activates Ca²⁺ release from the endoplasmic reticulum. Depending on the nature and intensity of the stimulus, Ca²⁺ increases of very different time and length scales can be observed. Specificity in the physiological responses is ensured by the high level of spatio-temporal organization of Ca²⁺ dynamics in the form of stochastic, sub-cellular increases, regular oscillations and intra- or intercellular Ca²⁺ waves (Dupont et al., 2007).

In this talk, I plan to focus on some specific aspects of Ca²⁺ oscillations in non-excitable cells. After discussing the general mechanism of oscillations, I will emphasize how a modeling approach can help to make the link between detailed aspects of their mechanism and the characteristics of the spikes. In particular, the number and the specific isoform of the Ca²⁺ channels can affect the regularity of oscillations as well as the shape of the spikes. I will also briefly talk about the mechanism of propagation of intercellular Ca²⁺ waves.

References:

Dupont G, Combettes L, Leybaert L. Calcium dynamics: spatio-temporal organization from the subcellular to the organ level. Int Rev Cytol. 2007;261:193-245.