Three-dimensional cytoplasmic calcium propagation with boundaries

TL;DR

This study investigates 3D calcium ion propagation within cells using simulations and theoretical models, revealing distribution scales, potential signaling mechanisms at ER-PM junctions, and kinase buffering effects, enhancing understanding of calcium signaling.

Contribution

It introduces a combined numerical and mean field approach to analyze 3D calcium distribution with boundaries, providing new insights into calcium signaling mechanisms.

Findings

Calcium distribution spans micrometer scales consistent with observed calcium waves.

Double messenger systems may operate efficiently at ER-PM junctions.

Buffer effects of kinases influence calcium and phosphorylation dynamics.

Abstract

Ca$^{2+}$ plays an important role in cell signal transduction. Its intracellular propagation is the most basic process of Ca$^{2+}$ signaling, such as calcium wave and double messenger system. In this work, with both numerical simulation and mean field ansatz, the 3-dimensional probability distribution of Ca$^{2+}$, which is read out by phosphorylation, is studied in two scenarios with boundaries. The coverage of distribution of Ca$^{2+}$ is found at an order of magnitude of $\mu$m, which is consistent with experimental observed calcium spike and wave. Our results suggest that the double messenger system may occur in the ER-PM junction to acquire great efficiency. The buffer effect of kinase is also discussed by calculating the average position of phosphorylations and free Ca$^{2+}$. The results are helpful to understand the mechanism of Ca$^{2+}$ signaling.