High yield purification of JNK1β1 and activation by in vitro reconstitution of the MEKK1 → MKK4 → JNK MAPK phosphorylation cascade

► Codon harmonization was used as a precautionary measure toward soluble JNK1β1 overexpression. ► JNK1β1 and ATF2 were purified in high yields to >99% purity using GST-tags. ► JNK1β1 was activated by reconstituting the MEKK1 → MKK4 → JNK MAPK pathway in vitro. ► Phosphorylated JNK1β1 had high specific activity toward its substrate, ATF2.