Abstract
Clusters of receptor channels in the membranes of the endoplasmic reticulum of many nonexcitable cells release calcium ions in a cooperative manner giving rise to dynamical patterns such as puffs, waves, and oscillations that occur on multiple spatial and temporal scales. We introduce a minimal yet descriptive reaction-diffusion model of receptors for a saturating concentration of using a principled reduction of a detailed Markov chain description of individual channels. A dynamical systems analysis reveals the possibility of excitable, bistable, and oscillatory dynamics of this model that correspond to three types of observed patterns of calcium release: puffs, waves, and oscillations, respectively. We explain the emergence of these patterns via a bifurcation analysis of a coupled two-cluster model, compute the phase diagram, and quantify the speed of the waves and period of oscillations in terms of system parameters. We connect the termination of large-scale release events to unbinding or stochasticity.
3 More- Received 14 November 2017
- Revised 29 March 2018
DOI:https://doi.org/10.1103/PhysRevE.98.032413
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