Ectopic expression of an activating mutant form of MK2 enhances TNF-α production but has no effect on IL-1β production. THP-1 cells were retrovirally transduced with either an expression vector containing complementary DNA coding for the catalytic domain of MK2 (MK2-CA; aa 49-338) or with the empty vector. Transduced cells were then selected using G418. (A) Whole cell extracts were prepared and subjected to western blot analysis to confirm expression of MK2 and MK2-CA. NS indicates a nonspecific band. (B-C) Cells were plated at a concentration of 106 per mL before stimulation with R848 (30 μM) for 24 hours. Secreted TNF-α (B) and IL-1β (C) were measured in the conditioned media by ELISA. Two experiments were carried out, and each consisted of 3 biological replicates for each condition. One representative experiment is shown.