MEK1/A0266

Dual specificity mitogen-activated protein kinase (MAPK) kinase 1 (MAP2K1, also known as MEK1 or A0266), is a dual specificity protein kinase.

Dual specificity mitogen-activated protein kinase (MAPK) kinase 1 (MAP2K1, also known as MEK1 or A0266), is a dual specificity protein kinase. These kinases have the specificity to phosphorylate not only serines and threonines, but also tyrosines. MEK1 phosphorylates threonine-glutamate-tyrosine sequences, and belongs to the STE group of protein kinases. MEK1 is a primary modulator of the MAPK pathway. The activation of MEK1 leads to phosphorylation and activation of extracellular signal-regulated kinase 1 (ERK1) and ERK2. The inhibition of this pathway affects synaptic physiology, preventing certain forms of long-term potentiation (LTP) and impairing different forms of long-term memory like spatial learning and fear conditioning. As with other members of the MAPKs, this protein is widely expressed in many tissues. The null mutation of MEK1 is lethal, and homozygous mutant embryos die at 10.5 days of gestation. Transgenic mice expressing dominant negative MEK1 shows, these animals presented a marked deficit in the contextual fear conditioning test.