Target information

ERK1 and ERK2 (extracellular signal-regulated kinase 1 and 2) are widely involved in the regulation of meiosis, mitosis, and post-mitotic functions in cells. ERK1 and ERK2 are members of the MAP kinase family, which act in a signaling cascade that regulates various cellular processes such as proliferation, differentiation, and cell cycle progression in response to a variety of extracellular signals. Different stimuli, including growth factors, cytokines, virus infection, ligands for heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors and transforming agents, activate the ERK1 and ERK2 pathways. Growth factors binding to the tyrosine kinase receptors, Ras/Raf activation, and serine/threonine protein kinase stimulation activate the ERK1/ERK2 pathways as well. ERK proteins are regulated by dual phosphorylation at Tyrosine 204 and 187, and Threonine 177 and 160 residues mapping within a characteristic Thr-Glu-Tyr motif. Phosphorylation at the Threonine 202 and Tyrosine 204 residues of ERK1, and Threonine 185 and Tyrosine 187 residues of ERK2 is required for full enzymatic activation. The structural consequences of dual-phosphorylation in the ERK2 include active site closure, alignment of key catalytic residues that interact with ATP, and remodeling of the activation loop. In response to activation, MAP kinases phosphorylate downstream components on serine and threonine. The ERK family has three additional members: ERK3, ERK5 and ERK6.