Ralimetinib selectively inhibits phosphorylation of MK2 (Thr334) and has no effect on phosphorylation of p38α MAPK, JNK, ERK1 2, c-Jun, ATF2, or c-Myc. Ralimetinib is an effective and selective, ATP-competitive inhibitor of p38 MAPK α β (IC50s: 5.3 and 3.