Target Information

MEK1 (Mitogen activated protein kinase 1) catalyzes the concomitant phosphorylation of a threonine and a tyrosine residue in a Thr-Glu-Tyr sequence located in MAP kinases. MEK1 activates ERK1 and ERK2 MAP kinases. Mitogen activated protein kinase 2 (MEK2 or MAPKK2) is a member of a family of tyrosine/threonine protein kinases that activate the ERK1 and 2 and MAPK enzymes by phosphorylating both residues within the threonine/glutamate/tyrosine (TEY) motif in the activation loop. MEK1 and 2 are also activated by dual phosphorylation, which occurs on serine 218 and 222, in the activation loop of the MEK. Threonine 292 of MEK1 is phosphorylated by ERK 2, which serves as a negative feedback loop by suppressing activation of MEK1.