Robust effects of Tsr-CheBp and CheA-CheYp affinity in bacterial chemotaxis.
OBJECTIVE
Cell motility and chemotaxis play a role in the virulence of pathogenic bacteria, such as escape from host immune responses. Escherichia coli chemotaxis provides a well-characterized model system for the bacterial chemotaxis network. Two features of E. coli chemotaxis include signal amplification and robustly accurate adaptation. Recent simulation studies with models considering the effects of other receptors have suggested possible mechanisms for signal amplification. Although precise adaptation to aspartate has been explained by conventional kinetic models, the adaptation behavior of models incorporating the effects of other receptors remains unclear.


METHODS
We concentrated on how receptor crosstalk affects minimization of adaptation error and compared models in which the contribution of other receptors varied.


RESULTS
We demonstrated that the model is adaptable to attractant concentrations ranging from 0.1microM to 10mM with a decreased error rate (from 8% to 2%) when the kinetic constant of CheA and phosphorylated CheY dissociation is increased.


CONCLUSIONS
The results suggest that accurate adaptation is maintained through control of both the interaction of cytoplasmic Che proteins and the activity of the receptor complex.
Matsuzaki
Yuri
Y
Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-8520, Japan.
Kikuchi
Shinichi
S
Tomita
Masaru
M
D000220:Adaptation, Biological / Q000502:physiology; D001426:Bacterial Proteins / Q000378:metabolism*; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology*; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D029968:Escherichia coli Proteins; D025461:Feedback, Physiological / Q000187:drug effects / Q000502:physiology; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000378:metabolism; D000072236:Methyl-Accepting Chemotaxis Proteins; D008745:Methylation / Q000187:drug effects; D008954:Models, Biological; D020239:Receptor Cross-Talk / Q000187:drug effects / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D049490:Systems Biology / Q000379:methods
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D011956:Receptors, Cell Surface; C057635:Tsr protein, Bacteria; C000607606:cheY protein, E coli; C000607604:tsr protein, E coli; D000071677:Histidine Kinase; C000607608:cheA protein, E coli