IκB flux controls the sensitivity of NFκB to stimulation by TNF and UV.

<p>(A) The futile flux of IκB was varied between and times its wildtype value prior to stimulation with variable doses of TNF (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1002932#s4" target="_blank">Methods</a>). For low, medium, high, and wildtype values of the futile flux, the area under the NFκB activation curve is plotted as a function of TNF dose. The region of the plot corresponding to low doses of TNF, where the activation of IKK does not exceed 10%, is shaded in pink. (B) As above, but variable doses of UV are used instead of TNF. Because the response to UV is sustained and not transient, we have plotted the value of as a function of UV dose instead of the area under the NFκB activation curve.