Modelling of simple and complex calcium oscillations - From single-cell responses to intercellular signalling

Item Type:	Review
Title:	Modelling of simple and complex calcium oscillations - From single-cell responses to intercellular signalling
Creators Name:	Schuster, S. and Marhl, M. and Hoefer, T.
Abstract:	This review provides a comparative overview of recent developments in the modelling of cellular calcium oscillations. A large variety of mathematical models have been developed for this wide-spread phenomenon in intra- and intercellular signalling. From these, a general model is extracted that involves six types of concentration variables: inositol 1,4,5-trisphosphate (IP 3), cytoplasmic, endoplasmic reticulum and mitochondrial calcium, the occupied binding sites of calcium buffers, and the fraction of active IP 3 receptor calcium release channels. Using this framework, the models of calcium oscillations can be classified into 'minimal' models containing two variables and 'extended' models of three and more variables. Three types of minimal models are identified that are all based on calcium-induced calcium release (CICR), but differ with respect to the mechanisms limiting CICR. Extended models include IP 3-calcium cross-coupling, calcium sequestration by mitochondria, the detailed gating kinetics of the IP 3 receptor, and the dynamics of G-protein activation. In addition to generating regular oscillations, such models can describe bursting and chaotic calciumdynamics. The earlier hypothesis that information in calcium oscillations is encoded mainly by their frequency is nowadays modified in that some effect is attributed to amplitude encoding or temporal encoding. This point is discussed with reference to the analysis of the local and global bifurcations by which calcium oscillations can arise. Moreover, the question of how calcium binding proteins can sense and transform oscillatory signals is addressed. Recently, potential mechanisms leading to the coordination of oscillations in coupled cells have been investigated by mathematical modelling. For this, the general modelling framework is extended to include cytoplasmic and gap-junctional diffusion of IP 3 and calcium, and specific models are compared. Various suggestions concerning the physiological significance of oscillatory behaviour in intra-and intercellular signalling are discussed. The article is concluded with a discussion of obstacles and prospects.
Keywords:	Bursting, Calcium Oscillations, Calcium-Induced Calcium Release, Entrainment, Frequency Encoding, Gap Junctions, Homoclinic Bifurcation, Hopf Bifurcation, Inositol 1,4,5-Trisphosphate, IP 3 Receptors
Source:	European Journal of Biochemistry
ISSN:	0014-2956
Publisher:	Blackwell Publishing
Volume:	269
Number:	5
Page Range:	1333-1355
Date:	1 January 2002
Official Publication:	https://doi.org/10.1046/j.0014-2956.2001.02720.x
PubMed:	View item in PubMed

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