
ERK1andERK2(alsoknownasMAPK3andMAPK1)are44-and42-kDaSer/Thrkinases,respectively.TheyarepartoftheRas-Raf-ERKsignaltransductioncascadeoftenfounddownstreamofgrowthfactorreceptoractivation.ERK1andERK2wereinitiallyisolatedandclonedaskinasesactivatedinresponsetoinsulinandNGF.Theyareexpressedinmost,ifnotall,mammaliantissues.DualthreonineandtyrosinephosphorylationactivatebothERKs,atThr202/Tyr204forhumanERK1andThr185/Tyr187forhumanERK2.
ERK1isinvolvedinvariouscellularproliferation,differentiation,andcellcycleprogressioninresponsetoavarietyofextracellularsignalsmakingitusefulforthestudyofprocesseslikeangiogenesis,neurogenesisandtumorigenesis.TheactivationofERKbyproinflammatorystimulimayplayimportantrolesininnateimmuneresponsesandautoimmunity.
Image:ERK1stainingofHumanNeuronsandGlia.Paraffin-EmbeddedFormalin-FixedTissue.