MAP kinase kinase 1 (MEK1) is an integral component of the MAP kinase cascade that regulates cell growth and differentiation.1,2 This pathway also plays a key role in synaptic plasticity in the brain.3 Activated MEK1 acts as a dual specificity kinase phosphorylating both a threonine and a tyrosine residue on MAP kinase.4,5,6WARNING This product is not for human or veterinary use.