Extracellular signal–regulated kinase 1/2 (ERK1/2), one major member of mitogen-activated protein kinases (MAPK) family, has been implicated in crucial roles in synaptic plasticity and hippocampus-dependent memory (Sweatt, 2004) as well as in cerebral ischemia (Sawe et al., 2008). The gene discussed is MAPK3; the disease is brain ischemia.