Recombinant full-length human ERK2 was expressed in E. coli with an N-terminal GST tag and activated by MEK1 in vitro.

ERK2 is a protein serine/threonine kinase that is a member of the extracellular signal-regulated kinases (ERKs) which are activated in response to numerous growth factors and cytokines. Activation of ERK2 requires both tyrosine and threonine phosphorylation that is mediated by MEK. ERK2 is ubiquitously distributed in tissues with the highest expression in heart, brain and spinal cord. Activated ERK2 translocates into the nucleus where it phosphorylates various transcription factors (Elk-1, c-Myc, c-Jun, c-Fos, and C/EBP beta).