BackgroundInformation | I.TESTPRINCIPLE TheUPSTATE®colorimetricSTAR(SignalTransductionAssayReaction)ELISAkitisasolidphasesandwichenzymelinkedimmunosorbentassaythatprovidesafast,sensitivemethodtodetectspecificlevelsofsignalingtargetsinwholecellextracts.Thep38MAPKplateiscoatedwithaspecificmousemonoclonalp38MAPKcaptureantibodyonthemicrowellsofthe96-wellclearplate.Samplelysateorthestandardincludedinthekitareincubatedinthemicrowellsallowingp38MAPKantigentobecapturedintheplatewells.Theplateisthenwashedtoremoveanynon-boundunspecificmaterial.Thewellsarethenincubatedwithaspecificrabbitanti-phospho-p38(Thr180/Tyr182)antibodytodetectthecapturedp38(Thr180/Tyr182)ontheplatewell.TheunbounddetectionantibodyiswashedawayfollowedbyincubationwithanHRP-conjugatedanti-rabbitantibody.Thisallowsforasensitiveenzymaticdetectionofthesample.AftertheadditionofTMBsubstrateandstopsolutiontheabsorbanceismeasuredat450nmusingaplatereader. Theentireassaytakeslessthan5hourstocompletewithminimalhands-ontime.Manyofthereagentsaresuppliedinready-touseformulationsforeaseofuse.Thekitalsoincludesastandardthatisrunasbothapositivecontrolandtodevelopastandardlineofdetection.
II.p38BACKGROUND Thep38MAPKfamilyofSer/Thrkinaseproteinsismadeupof4isoforms,p38alpha(MAPK14andSAPK2a),p38beta(MAPK11andSAPK2b),p38delta(MAPK13,SAPK4),andp38gamma(MAPK12,SAPK3).Theotherp38isoformsshare74%,57%,and60%sequenceidentitywiththealphaisoform,respectively.AllfourisoformspossestheTGYmotifandareactivatedbythedualphosphorylationofthethreonineandtyrosineresiduesinthismotif,whichcorrespondtoThr180/Tyr182inhumanp38alpha.p38,especiallythealphaandbetaisoforms,areabletophosphorylateawidearrayoftargetsincludingnumerouskinasesincludingMAPKAP-K2,MAPKAP-K3,PRAK,MSK,andMNKaswellastranscriptionfactorsincludingSTAT1,p53,NFATp,ATF-2,Elk-1(althoughweakly),andMEF2a/c.p38MAPKfamilymembershavetrADItionallybeenassociatedwithstress,immuneresponse,andregulationofcellproliferationandapoptosis.Theyalsohavearoleinregulatingtheproductionofpro-inflammatorycytokinesandhavebeenassociatedwithdiseasessuchasasthmaandseveralautoimmunediseases,includingrheumatoidarthritis,diabetes,andinflammatoryboweldisease.JustasERKisphosphorylatedandactivatedbyMEK,p38alphaMAPKinaseisactivatedpredominantlybyitsupstreamregulatorykinasesMKK6andMKK3aswellasMKK4whichalsoactivatesJNK,butisnotasubstrateforMKK7likeJNKis. |