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Comment
. 2002 Jan 8;99(1):7-9.
doi: 10.1073/pnas.022641699.

Bacterial chemotaxis and the question of gain

Dennis Bray  1
Affiliations
Comment

Bacterial chemotaxis and the question of gain

Dennis Bray. Proc Natl Acad Sci U S A. .
No abstract available

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Figures

Figure 1
Figure 1
Chemotactic gain. If an E. coli cell swims into the attractant molecule aspartate, this will lead to an increase in the occupancy of aspartate receptors, typically clustered at one end of the cell, as shown here. A cascade of signal transduction events then leads to a fall in the cytosolic concentration of the protein CheYp, which diffuses to one of the flagellar motors. A fall in CheYp concentration at the motor increases the probability that it will turn in a counterclockwise direction, causing the bacterium to persist in this favorable direction. The probability that a motor turns counterclockwise is expressed as the rotational bias. The chemotactic gain, which is the subject of this commentary, is simply the change in bias divided by the change in occupancy.
Figure 2
Figure 2
Excitatory signal cascade. That portion of the signal cascade that relays a change in aspartate binding to a change in swimming behavior is shown in simplified form. Reactions responsible for adaptation are omitted for clarity. Tar is the receptor that binds aspartate (asp); CheA is the autophosphorylating kinase; CheY is the response regulator. After phosphorylation by CheA, CheYp diffuses to the six or so flagellar motors, increasing the likelihood that they turn clockwise and thereby initiate a tumble. CheZ is a protein that interacts with CheYp and stimulates its dephosphorylation. For further details see ref. .
See this image and copyright information in PMC

Comment on

  • Receptor sensitivity in bacterial chemotaxis.
    Sourjik V, Berg HC. Sourjik V, et al. Proc Natl Acad Sci U S A. 2002 Jan 8;99(1):123-7. doi: 10.1073/pnas.011589998. Epub 2001 Dec 11. Proc Natl Acad Sci U S A. 2002. PMID: 11742065 Free PMC article.

References

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