In order to further test our model, we examined Akt phosphorylation after inhibition of a downstream kinase in the pathway, JNK. However, we found that SP600125, which protected L929 cells from death and inhibited TNFα production (Fig. 2A,B S2A S10A), inhibited both basal and post-treatment phosphorylation levels of Akt at both Ser473 and Thr308 (Fig. S10B). It has been published that SP600125 is a somewhat non-specific inhibitor that may inhibit the p110δ subunit of PI3K [41] and PDK1 [42]. Both of these off-target effects could inhibit basal Akt phosphorylation levels, precluding the use of SP600125 in this system.