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BP: Fachverband Biologische Physik
BP 1: Statistical Physics in Biological Systems I (joint DY, BP)
BP 1.3: Talk
Monday, March 14, 2011, 11:00–11:15, ZEU 250
The energy-speed-accuracy tradeoff in sensory adaptation — Ganhui Lan1, •Pablo Sartori2, Silke Neumann3, Viktor Sourjik3, and Yuhai Tu1 — 1IBM T. J. Watson Research Center, Yorktown Heights, NY 10598, USA — 2Max Planck Institute for the Physics of Complex Systems, Dresden 01187, Germany — 3Zentrum fur Molekulare Biologie der Universitat Heidelberg, Heidelberg, Germany
Adaptation is a fundamental function of living systems. The benefits of adaptation in sensory systems are well known, but its costs remain poorly understood. By analyzing a stochastic model of the generic feedback circuit responsible for sensory adaptation, we show that adaptation processes are inherently dissipative and continuous energy consumption is required to stabilize the adapted state. We derive a universal relation among energy dissipation rate, adaptation speed, and the maximum adaptation accuracy from our model. We demonstrate how this general energy-speed-accuracy (ESA) relation applies to the E. coli chemosensory system, where hydrolysis of the S-adenosylmethionine (SAM) molecules drives the near-perfect adaptation of the system and maintains its high sensitivity in a wide range of backgrounds. We identify the key requirements for an adaptive network to achieve its maximum accuracy with a given energy budget. These requirements are met in the E. coli chemotaxis pathway, making it highly efficient. Moreover, direct measurements confirm that adaptation slows down as cells gradually de-energize in medium without nutrients.