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  • Open Access

Information thermodynamics of cellular ion pumps

Julián D. Jiménez-Paz1,2,3, Matthew P. Leighton1,4,*,†, and David A. Sivak1,*,‡

  • *These authors contributed equally to this work.
  • †Contact author: matthew.leighton@yale.edu
  • ‡Contact author: dsivak@sfu.ca
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Phys. Rev. Research 8, 013155 – Published 10 February, 2026

DOI: https://doi.org/10.1103/n121-br2w

Abstract

The framework of bipartite stochastic thermodynamics is a powerful tool to analyze a composite system's internal thermodynamics. It has been used to study the components of different molecular machines such as ATP synthase. However, this approach has not yet been used to describe ion-transporting proteins despite their high-level functional similarity. Here, we study the bipartite thermodynamics of the sodium-potassium pump in the nonequilibrium steady state. Using a physically intuitive partition between the ATP-consuming subsystem and the ion-transporting subsystem, we find considerable information flow comparable to other molecular machines, and Maxwell-demon behavior in the ATP-consuming subsystem. We vary ion concentrations and transmembrane voltage in a range including the neuronal action potential, and find that the information flow inverts during depolarization.

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Outline

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Phys. Rev. Research 8, 013155– Published 10 February, 2026
  • Received 12 June 2025
  • Accepted 12 January 2026
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