Dynamics of intracellular Ca$^{2+}$ oscillations in the presence of multisite Ca$^{2+}$-binding proteins

TL;DR

This study explores how multisite calcium-binding proteins influence intracellular calcium oscillations, revealing they set thresholds for oscillation onset and can induce stochastic coherence, impacting cellular communication.

Contribution

It demonstrates that multisite calcium-binding proteins actively regulate calcium oscillations and can induce stochastic coherence, challenging the view of them as passive buffers.

Findings

Multisite calcium-binding proteins set a sharp threshold for calcium oscillations.

Internal noise can induce self-oscillations even at high protein concentrations.

Oscillation regularity peaks at an optimal noise level, indicating stochastic coherence.

Abstract

We study the dynamics of intracellular calcium oscillations in the presence of proteins that bind calcium on multiple sites and that are generally believed to act as passive calcium buffers in cells. We find that multisite calcium-binding proteins set a sharp threshold for calcium oscillations. Even with high concentrations of calcium-binding proteins, internal noise, which shows up spontaneously in cells in the process of calcium wave formation, can lead to self-oscillations. This produces oscillatory behaviors strikingly similar to those observed in real cells. In addition, for given intracellular concentrations of both calcium and calcium-binding proteins the regularity of these oscillations changes and reaches a maximum as a function noise variance, and the overall system dynamics displays stochastic coherence. We conclude that calcium-binding proteins may have an important and active role in cellular communication.