Dual substrate assay with compounds. Each compound was run in the dual substrate assay: A, SD-0006, B, BIRB 796, C, CMPD1, D, SD-0006, E, BIRB 796, F CMPD1. Phosphorylation of MK2 by p38 (left panels) was measured at 30 min for either MK2 alone (Δ) or MK2 + ATF2 (□). Phosphorylation of ATF2 by p38 (right panels) was measured at 120 min for either ATF2 alone (▽) or MK2 + ATF2 (□). Data is shown as a fraction of the maximum value ± standard deviation (n = 2) and IC50 values for each compound/substrate are listed in Table 3.