MEK Inhibitor U0126 is a chemically synthesized organic compound that inhibits activation of MAPK (ERK 1/2) by inhibiting the kinase activity of MAP Kinase Kinase (MAPKK or MEK 1/2). U0126 inhibits MEK1 with an IC50 of 0.5uM (in vitro). It has been used in both in vivo and in vitro studies of MEK.
