MAP2K2 (Mitogen-Activated Protein Kinase Kinase 2), also known as MEK2, is a dual-specificity protein kinase that functions as the second kinase in the MAPK/ERK cascade, directly phosphorylating and activating ERK1 and ERK2. MEK2 shares significant homology with MEK1 and has both overlapping and distinct functions in neuronal signaling and synaptic plasticity.
MEK2 has a similar structure to MEK1:
MEK2 exists as two isoforms (MEK2a and MEK2b) with different N-terminal sequences. The enzyme requires dual phosphorylation on S222 and S226 for full activation. Structural studies show the inactive conformation with the activation loop in a closed state.
MEK2 has critical functions in the nervous system: