Information processing and signal integration in bacterial quorum sensing

TL;DR

This paper introduces an information-theoretic framework to analyze how Vibrio harveyi bacteria integrate multiple autoinducer signals in quorum sensing, revealing constraints on network architecture and strategies to minimize signal interference.

Contribution

It develops a novel information theory-based approach to quantify signal integration in bacterial quorum sensing and explains the observed input-output behavior in V. harveyi.

Findings

Bacteria optimize signal integration to reduce interference.

Autoinducer production and receptor feedback are key strategies.

The network architecture is constrained by interference minimization.

Abstract

Bacteria communicate using secreted chemical signaling molecules called autoinducers in a process known as quorum sensing. The quorum-sensing network of the marine bacterium {\it Vibrio harveyi} employs three autoinducers, each known to encode distinct ecological information. Yet how cells integrate and interpret the information contained within the three autoinducer signals remains a mystery. Here, we develop a new framework for analyzing signal integration based on Information Theory and use it to analyze quorum sensing in {\it V. harveyi}. We quantify how much the cells can learn about individual autoinducers and explain the experimentally observed input-output relation of the {\it V. harveyi} quorum-sensing circuit. Our results suggest that the need to limit interference between input signals places strong constraints on the architecture of bacterial signal-integration networks, and that bacteria likely have evolved active strategies for minimizing this interference. Here we analyze two such strategies: manipulation of autoinducer production and feedback on receptor number ratios.