The antibodies provided in this kit recognizes human, mouse and rat Erk1 phosphorylated at sites Thr202/Tyr204, Erk2 phosphorylated at sites Thr185/Tyr187, JNK phosphorylated at sites Thr183/Tyr185 and p38 phosphorylated at sites Thr180/Tyr182. This kit also recognizes total Erk1/2, total JNK and total p38 for comparison.