Figure 1

Schematic presentation of the different mammalian MAP kinase pathways. The conventional MAP kinase pathways, represented by the MEK/ERK, JNK, p38^MAPK, and MEK5/ERK5 pathways, consist of a module of three kinases that subsequently phosphorylate and active each other. The MAPK kinase kinase (MAP3K) phosphorylates MAPK kinase (MAP2K), which in turn phosphorylates MAPK. Downstream of MAPK are substrates including other protein kinases referred to as MAPK-activated protein kinases (MAPKAPK). The atypical pathways include ERK3, ERK4, ERK7, ERK8, and NLK. MAPKs can converge to different MAPKAPK as shown in this figure.