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《Selective dephosphorylation of the threonine183 residue of ERK2 upon对uponkllbKllbL3 engagement in plateletsl3参与血小板ERK2 threonine183残留选择性的去磷酸化》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、FEBS26181FEBSLetters521(2002)145^151Selectivedephosphorylationofthethreonine183residueofERK2uponKllbL3engagementinplateletsMarcPawlowskia,AshrafRagabb,Jean-PhilippeRosaa,MarijkeBryckaerta;aU348INSERM,IFR-6CirculationLariboisie're,Ho“pitalLariboisie're,41BvddelaChapelle,75475ParisCedex10,F
2、rancebU563INSERM,IFR30,Ho“pitalPurpan,31059ToulouseCedex,FranceReceived10May2002;accepted14May2002Firstpublishedonline29May2002EditedbyJesusAvilastreamMAPKkinases,MEK1orMEK2[2].TheregulationAbstractThrombin-inducedextracellularsignal-regulatedki-ofERK2activityinvolvesseveraltypesofphosphat
3、asesthatnase2(ERK2)activationisnegativelyregulatedinconditionsofKllbL3integrinengagementandplateletaggregation.Herewedephosphorylateboththreonineandtyrosineactivatingresi-showbyWesternblottingwithantibodiesagainstmono-anddues.Thedual-speci¢cthreonine/tyrosinephosphatasefamily,biphosphoryla
4、tedformsofERK2thatthedephosphorylationofalsocalledtheMAPKphosphatasefamily,includesMKP-1,ERK2byKllbL3engagementaffectsthreonine183andnotPAC-1,MKP-3orMKP-4.Themembersofthisfamilyin-tyrosine185.Additionofapotentserine/threoninephosphataseactivateERK,thepatternofinactivationdependingoncellinh
5、ibitor,okadaicacid(OA),restoredthrombin-inducedthreo-typeandthecytosolicornuclearlocation[3].MKP-3andninephosphorylationofERK2inconditionsofplateletaggrega-MKP-4havebeenshowntobemorespeci¢cforERKthantion,whereasOAhadnoeffectintheabsenceofKllbL3JNKsandp38MAPKs[4^5].MKP-3substrateselectivity
6、engagement.TheseobservationsareconsistentwithKllbL3appearstodependprimarilyontheN-terminal-speci¢cregionengagementactingviaatleastoneserine/threoninephosphatase,183ofthephosphataseandthenonsubstraterecognitiondomainswhichdephosphorylatesthephosphothreonineresidueofERK2.Moreover,asmallamoun
7、t(14%)ofERK2waswithinERK[6^7].Serine/threoninephosphatase1(PP1)andtranslocatedtotheKllbL3-dependentcytoskeleton,mostlyinPP2Ahavebeenalsoshowntoinhibittheactivityoftheamonophosphorylated(i.e.inactive)form,suggestingthatERK1/2pathwaybythedephosphorylationofMEK1/