Nonequilibrium sensing and its analogy to kinetic proofreading

TL;DR

This paper investigates how nonzero affinity, driven by ATP hydrolysis, enhances receptor sensitivity in chemotaxis and draws an analogy to kinetic proofreading, revealing energy consumption's role in sensing accuracy.

Contribution

It establishes a quantitative link between nonequilibrium receptor sensing and kinetic proofreading, highlighting how energy consumption improves sensing accuracy.

Findings

Affinity increases integrated sensitivity in chemotaxis receptors.

An analogy between nonequilibrium sensing and kinetic proofreading is demonstrated.

Nonzero affinity can sometimes decrease sensitivity, indicating anti-proofreading regimes.

Abstract

For a paradigmatic model of chemotaxis, we analyze the effect how a nonzero affinity driving receptors out of equilibrium affects sensitivity. This affinity arises whenever changes in receptor activity involve ATP hydrolysis. The sensitivity integrated over a ligand concentration range is shown to be enhanced by the affinity, providing a measure of how much energy consumption improves sensing. With this integrated sensitivity we can establish an intriguing analogy between sensing with nonequilibrium receptors and kinetic proofreading: the increase in integrated sensitivity is equivalent to the decrease of the error in kinetic proofreading. The influence of the occupancy of the receptor on the phosphorylation and dephosphorylation reaction rates is shown to be crucial for the relation between integrated sensitivity and affinity. This influence can even lead to a regime where a nonzero affinity decreases the integrated sensitivity, which corresponds to anti-proofreading.