The dual specific threonine/tyrosine kinase MEK is a key component of the RAS/RAF/MEK/ERK signaling pathway that regulates a diverse array of cellular processes. SL 327 is an inhibitor of MEK1 and MEK2 (IC50s = 0.18 and 0.22 μM), the kinases upstream of ERK1/2. It inhibits ERK1, MKK/p38, MKK4, JNK, and PKC at much higher concentrations (IC50s = >50, 21, >100, >100, >10 μM, respectively). Since SL 327 rapidly passes the blood-brain barrier, it has been used to dissect the effect of RAS/RAF/MEK/ERK signaling pathway inhibition on behavior, including long-term memory, spatial learning, and fear/operant conditioning.
