Figure 1.

Schematic representation of JNK signaling. The JNK pathway is activated in multiple cells by various extracellular factors (including stresses and cytokines) and is involved in different cellular processes through multiple intracellular signaling. Extracellular factors lead to the activation of mitogen-activated protein kinase kinase kinases (MAPKKKs). MAPKKK activates either MAP kinase kinase 4 or 7; both MAPKK4/7 activates the JNKs MAPK. JNK activation leads to specific substrates activation and subsequent cell transcription. ASK, activator of S-phase kinase; ATF, activating transcription factor; Elk-1, member of the ETS oncogene family; JNK, c-Jun NH2-terminal kinase.