c-Jun N-terminal Kinase (JNK) is a Stress Activated Protein Kinase/Map Kinase (SAPK/MAPK) represented by three isoforms, JNK1 (~49 kDa), JNK2 (~55 kDa), and JNK3 (~54 kDa). JNK is dually phosphorylated and therefore fully activated by MEK4 and MEK7 on threonine 183 and tyrosine 185 within the activation loop.
