<p>(A) Comparison of experimental data (filled boxes, data taken from <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003614#pcbi-1003614-g004" target="_blank">Fig. 4A</a> of Ref. <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003614#pcbi.1003614-Jiang3" target="_blank">[27]</a>) with the steady state response curve calculated from the extended Batchelor-Goulian model in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003614#pcbi.1003614.e180" target="_blank">Eqs. (22)</a>–<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003614#pcbi.1003614.e187" target="_blank">(29)</a> with an extra term ‘’ added to <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003614#pcbi.1003614.e180" target="_blank">Eq. (22)</a>, which accounts for autodephosphorylation of NRI-P. The blue dashed line represents the best fit obtained for , , and . The other parameters were kept fixed: , , , so that and corresponding to a half-life of 5 minutes <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003614#pcbi.1003614-Jiang3" target="_blank">[27]</a>. (B) As the autodephosphorylation rate constant of NRI-P is lowered (bottom to top: , , , ) the response curve becomes more and more ultrasensitive (solid lines). Note that ultrasensitivity is restricted to the region as predicted by <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003614#pcbi.1003614.e293" target="_blank">Eq. (38)</a>. The dashed (blue) lines in (A) and (B) are identical.</p
