The Energy Cost of Sensory Adaptation

Abstract

Biological sensory systems adapt to prolonged stimuli in order to maintain high sensitivity in different environments. Sensory adaptations are carried out by various molecular feedback mechanisms. Here, we show that all adaptation dynamics are dissipative and feedback control consumes energy to achieve high adaptation accuracy against intrinsic fluctuations in the underlying molecular signaling pathways. A universal relation among energy dissipation rate, adaptation time, and the optimum adaptation accuracy is established in a general continuum model and for the specific case of adaptation in E. coli chemotaxis. Our study finds that sensory adaptations are fueled by high-energy biomolecules (e.g., ATP), which provide the energy necessary in stabilizing the adapted state. For E. coli chemotaxis, hydrolysis of S-adenosylmethionine (SAM) drives the chemo-receptor adaptation, and the high energy content in SAM is crucial in maintaining the near perfect adaptation of the system. Finally, we point out that the energy-accuracy relation found here has deep connections with the energy dissipation required for molecular level error-correction and information processing.View Large Image | View Hi-Res Image | Download PowerPoint Slide