Dissipation in Non-Steady State Regulatory Circuits

Paulina Szymańska-Rożek,Dario Villamaina,Aleksandra M Walczak,Jacek Miȩkisz

doi:10.3390/e21121212

Abstract

In order to respond to environmental signals, cells often use small molecular circuits to transmit information about their surroundings. Recently, motivated by specific examples in signaling and gene regulation, a body of work has focused on the properties of circuits that function out of equilibrium and dissipate energy. We briefly review the probabilistic measures of information and dissipation and use simple models to discuss and illustrate trade-offs between information and dissipation in biological circuits. We find that circuits with non-steady state initial conditions can transmit more information at small readout delays than steady state circuits. The dissipative cost of this additional information proves marginal compared to the steady state dissipation. Feedback does not significantly increase the transmitted information for out of steady state circuits but does decrease dissipative costs. Lastly, we discuss the case of bursty gene regulatory circuits that, even in the fast switching limit, function out of equilibrium.

Highlights

Cells rely on molecular signals to inform themselves about their surroundings and their own internal state [1]
A constraint will be set on the steady state dissipation rate σss as in Mancini et al [66]
To compare the information transmitted in the models, and its cost, we will calculate the average dissipation of the models

Summary

Introduction

Cells rely on molecular signals to inform themselves about their surroundings and their own internal state [1] These signals can describe the surrounding sugar type and concentration, which is the case of many bacterial operons, such as those used for lactose or galactose breakdown [2]. Signaling and activation of phosphorylated receptors provide a means of informing bacterial cells on faster timescales about a wide range of conditions including crowding, growth signals, and stress [3]. Triggered by these signals cells activate regulatory networks and cascades that allow them to respond in an appropriate way to existing signals.

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