(A) Depletion of LZAP increases phosphorylation of p38 targets, but does not alter phosphorylation of MKK3/MKK6. U2OS cells were transfected with control siRNA or siRNA targeting LZAP before stimulation with TNFα, IL-1β, or LPS. Phosphorylation of direct or indirect p38 targets ATF2, MAPKAPK2, HSP27 and activators of p38, MKK3 and MKK6, was visualized by immunoblotting. LZAP knockdown was confirmed by immunoblotting and expression of GAPDH was used as a loading control. (B) LZAP inhibits transcriptional activity of the p38 target ATF2. U2OS cells were transfected with plasmids directing expression of GAL-ATF2 and p38, with or without increasing amounts of LZAP along with a luciferase reporter containing the GAL DNA binding sequence, as indicated. Firefly luciferase activity was normalized based on renilla luciferase activity and assigned a value of 1 in cells without transfected LZAP. All normalized luciferase assay data are expressed as the mean with the standard error and are the result of the least three independent experiments.