title: Tandem adaptation with a common design in Escherichia coli chemotaxis.
abstract: We analyze a model for motor-level adaptation in Escherichia coli based upon the premise that clockwise (CW) and counter-clockwise (CCW) states have different preferred numbers of FliM subunits. We show that this model provides a simple mechanism for the recently observed motor-level adaptation, and it also explains the long-lasting puzzle on the thresholds observed when tethered cells are used to monitor responses to temporal ramps. We note that the motor-level adaptation has the same negative-feedback network design as the upstream receptor-level adaptation, and the tandem architecture of one control circuit followed by the other mitigates the effects of cell-to-cell variation and broadens the range of stimuli over which cells optimally respond.
authors.affiliation: IBM T. J. Watson Research Center, 1101 Kitchwan Rd., Yorktown Heights, NY 10598, USA. Electronic address: yuhai@us.ibm.com.
authors.forename: Yuhai
authors.initials: Y
authors.lastname: Tu
authors.forename: Howard C
authors.initials: HC
authors.lastname: Berg
mesh_terms: D000222:Adaptation, Physiological; D002633:Chemotaxis; D004926:Escherichia coli / Q000502:physiology*; D005407:Flagella / Q000502:physiology