Information Thermodynamics Derives the Entropy Current of Cell Signal Transduction as a Model of a Binary Coding System

Abstract

Abstract:The analysis of cellular signaling cascades based on information thermodynamics has recently developed considerably. A signaling cascade may be considered a binary code system consisting of two types of signaling molecules that carry biological information, phosphorylated active, and non-phosphorylated inactive forms. This study aims to evaluate the signal transduction step in cascades from the viewpoint of changes in mixing entropy. An increase in active forms may induce biological signal transduction through a mixing entropy change, which induces a chemical potential current in the signaling cascade. We applied the fluctuation theorem to calculate the chemical potential current and found that the average entropy production current is independent of the step in the whole cascade. As a result, the entropy current carrying signal transduction is defined by the entropy current mobility.

The Conservation of Average Entropy Production Rate in a Model of Signal Transduction: Information Thermodynamics Based on the Fluctuation Theorem

“…Cell signal transduction is a non-equilibrium process, which is characterized by the existence of signal transduction caused by a chemical reservoir of energetic metabolites, such as adenosine triphosphate (ATP). Systems biology has been developed to analyze the signal transduction network [1][2][3][4][5][6][7][8], including computational neural network studies [2,9,10]. Methodologies for analyzing gene expression associated with protein-protein interactions [11][12][13][14][15][16] and studies of cancer cells have been conducted [17,18].…”

Information Thermodynamics of Cell Signal Transduction

“…(15) and (16) are obtained. In conclusion, the AEPR is conserved during the whole cascade of signal transduction [16].…”

“…The Lagrange undetermined constant method is adopted for this. If the constraint conditions are given by (5), (7), and (9), the function G can be defined as follows [16]:…”

“…This fluctuation theorem leads to various nonequilibrium relations among cumulates of the current. We have an equation below using signal current density [16,24]:…”

“…Meanwhile, considering specific reaction kinetics and thermodynamic analysis in individual reactions, there have been few studies discussing signal transduction, for example, limited to chemotaxis models of Escherichia coli [7], and several theoretical researches about mitogen-activated protein kinase (MAPK) cascade and bistability or ultra-sensitivity and feedback controllability of the cascade have been reported [8][9][10][11][12][13]. In addition, information thermodynamics of MAPK cascade has been recently reported [14][15][16]. This article reviews these recent studies from information thermodynamics in relation to fluctuation theorem.…”