caa a22 4500 445391707 CHVBK 20180317143048.0 cr unu---uuuuu 170323e20110401xx s 000 0 eng 10.1007/s10955-011-0169-z doi (NATIONALLICENCE)springer-10.1007/s10955-011-0169-z Noise Filtering Strategies in Adaptive Biochemical Signaling Networks [Elektronische Daten] Application to E. Coli Chemotaxis [Pablo Sartori, Yuhai Tu] Two distinct mechanisms for filtering noise in an input signal are identified in a class of adaptive sensory networks. We find that the high-frequency noise is filtered by the output degradation process through time-averaging; while the low-frequency noise is damped by adaptation through negative feedback. Both filtering processes themselves introduce intrinsic noises, which are found to be unfiltered and can thus amount to a significant internal noise floor even without signaling. These results are applied to E. coli chemotaxis. We show unambiguously that the molecular mechanism for the Berg-Purcell time-averaging scheme is the dephosphorylation of the response regulator CheY-P, not the receptor adaptation process as previously suggested. The high-frequency noise due to the stochastic ligand binding-unbinding events and the random ligand molecule diffusion is averaged by the CheY-P dephosphorylation process to a negligible level in E. coli. We identify a previously unstudied noise source caused by the random motion of the cell in a ligand gradient. We show that this random walk induced signal noise has a divergent low-frequency component, which is only rendered finite by the receptor adaptation process. For gradients within the E. coli sensing range, this dominant external noise can be comparable to the significant intrinsic noise in the system. The dependence of the response and its fluctuations on the key time scales of the system are studied systematically. We show that the chemotaxis pathway may have evolved to optimize gradient sensing, strong response, and noise control in different time scales. Springer Science+Business Media, LLC, 2011 Noise nationallicence Adaptation nationallicence Bacterial chemotaxis nationallicence Signal transduction nationallicence Networks nationallicence Sartori Pablo Max Planck Institute of Complex Systems, Nothnitzer Str. 38, 01187, Dresden, Germany aut Tu Yuhai IBM T.J. Watson Research Center, 10510, Yorktown Heights, NY, USA aut Journal of Statistical Physics Springer US; http://www.springer-ny.com 142/6(2011-04-01), 1206-1217 0022-4715 142:6<1206 2011 142 10955 https://doi.org/10.1007/s10955-011-0169-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10955-011-0169-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sartori Pablo Max Planck Institute of Complex Systems, Nothnitzer Str. 38, 01187, Dresden, Germany aut NATIONALLICENCE 700 1- Tu Yuhai IBM T.J. Watson Research Center, 10510, Yorktown Heights, NY, USA aut NATIONALLICENCE 773 0- Journal of Statistical Physics Springer US; http://www.springer-ny.com 142/6(2011-04-01), 1206-1217 0022-4715 142:6<1206 2011 142 10955 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer