mouse monoclonal IgG2a; p-ERK Antibody (E-4) is an IgG2a κ mouse monoclonal p-ERK antibody (also designated p-ERK antibody or p44/42 MAPK antibody) that detects ERK 1 phosphorylated at Tyr 204 and correspondingly phosphorylated ERK 2 of mouse, rat and human origin by WB, IP, IF, IHC(P) and ELISA. p-ERK Antibody (E-4) is available as the non-conjugated anti-p-ERK antibody form, as well as multiple conjugated forms of anti-p-ERK antibody, including agarose, HRP, PE, FITC and multiple Alexa Fluor® conjugates. The activation of signal transduction pathways by growth factors, hormones and neurotransmitters is mediated through two closely related MAP kinases, p44 and p42, designated extracellular-signal related kinase 1 (ERK 1) and ERK 2, respectively. ERK proteins are regulated by dual phosphorylation at specific tyrosine and threonine sites mapping within a characteristic Thr-Glu-Tyr motif. Phosphorylation at both the Thr and Tyr residues is required for full enzymatic activation. In response to activation, MAP kinases phosphorylate downstream components on serine and threonine. Upstream MAP kinase regulators include MAP kinase kinase (MEK), MEK kinase and Raf-1. The ERK family has three additional members: ERK 3, ERK 5 and ERK 6.