Cell Signaling

Enlightening the Load

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Science  21 Oct 2011:
Vol. 334, Issue 6054, pp. 291
DOI: 10.1126/science.334.6054.291-c

If you have driven a car with a manual transmission, you are aware that the response to the throttle is quite different when the drive train is connected to a “load” (when the clutch is engaged and the engine drives the wheels) than when it is not (when the engine spins freely with the clutch disengaged). Jiang et al. explored whether a similar concept of “load” applies to biochemical signaling systems; that is, whether the dynamic properties of a signaling mechanism were altered in the presence or absence of substrate molecules that are targets of the system. Combined experiments and mathematical modeling showed that the presence of substrate could alter the response time of the system, increasing it when one of the enzymes in the signaling system was operating at a maximal rate (saturated) but decreasing it when the enzymes were operating in a linear manner. The authors discuss how such effects of downstream targets on the responsiveness of signaling systems might be used to design appropriate responses when modifying biological systems or designing synthetic ones.

Sci. Sig. 4, ra67 (2011).

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