Energy dissipation drives the gradient signal amplification through an incoherent type-1 feed-forward loop

Ganhui Lan
Phys. Rev. E 92, 032702 – Published 2 September 2015

Abstract

We present here the analytical relation between the gain of eukaryotic gradient sensing network and the associated thermodynamic cost. By analyzing a general incoherent type-1 feed-forward loop, we derive the gain function (G) through the reaction network and explicitly show that G depends on the nonequilibrium factor (0γ1 with γ=0 and 1 representing irreversible and equilibrium reaction systems, respectively), the Michaelis constant (KM), and the turnover ratio (rcat) of the participating enzymes. We further find the maximum possible gain is intrinsically determined by KM/Gmax=(1/KM+2)/4. Our model also indicates that the dissipated energy (measured by lnγ), from the intracellular energy-bearing bioparticles (e.g., ATP), is used to generate a force field Fγ(1γ) that reshapes and disables the effective potential around the zero gain region, which leads to the ultrasensitive response to external chemical gradients.

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  • Received 22 April 2015

DOI:https://doi.org/10.1103/PhysRevE.92.032702

©2015 American Physical Society

Authors & Affiliations

Ganhui Lan

  • Department of Physics, George Washington University, Washington, DC 20052, USA

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Vol. 92, Iss. 3 — September 2015

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