Systems Biology

Intrinsically Responsive

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Science  10 Apr 2009:
Vol. 324, Issue 5924, pp. 151
DOI: 10.1126/science.324.5924.151c

Members of the mitogen-activated protein kinase family regulate a wide range of biological processes. Macia et al. have found that although the activity of the yeast mitogen-activated protein kinase (MAPK) Hog1, which helps yeast to survive osmotic stress, increases when yeast is exposed to high salt concentrations, the kinase appeared to be active under basal conditions. In fact, signaling activity in the absence of stress was held in check by a negative feedback loop that required the kinase activity of Hog1. A model of this circuit recapitulated the experimental data and suggested that intrinsic basal signaling poises the system to respond rapidly to even small changes in osmolarity. A similar basal activity was detected for two additional yeast MAPKs, which are involved in the pheromone response, suggesting that high basal signaling may be a common property of MAPK pathways. — NRG*

Sci. Signal. 2, ra13 (2009).

  • * Nancy Gough is Editor of Science Signaling.

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