More About MEK
Four distinct MAPK cascades have been identified and named according to their MAPK module. These are extra-cellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), p38 and ERK5. MEK proteins (EC 2.7.12.1) belong to a family of enzymes that lie upstream to their specific MAPK targets in MAP kinase signaling pathways, and so far 7 MEK enzymes have been identified. MEK1 and MEK2 are closely related. They both participate in the Ras/Raf/MEK/ERK signal transduction cascade. MEK1 (a.k.a. MAPKK-1 or MAP2K1) is the prototype member of MEK family proteins[1].
[1] A. Akinleye et al. MEK and the inhibitors: from bench to bedside. J. Hematol. Oncol. 2013, 6, 27-38.