UniProtSummary | FUNCTION:SwissProt:Q14790#MostupstreamproteaseoftheactivationcascadeofcaspasesresponsiblefortheTNFRSF6/FASmediatedandTNFRSF1Ainducedcelldeath.BindingtotheadaptermoleculeFADDrecruitsittoeitherreceptor.Theresultingaggregatecalleddeath-inducingsignalingcomplex(DISC)performsCASP8proteolyticactivation.TheactivedimericenzymeisthenliberatedfromtheDISCandfreetoactivatedownstreamapoptoticproteases.ProteolyticfragmentsoftheN-terminalpropeptide(termedCAP3,CAP5andCAP6)arelikelyretainedintheDISC.CleavesandactivatesCASP3,CASP4,CASP6,CASP7,CASP9andCASP10.MayparticipateintheGZMBapoptoticpathways.CleavesADPRT.Hydrolyzesthesmall-moleculesubstrate,Ac-Asp-Glu-Val-Asp--AMC.LikelytargetforthecowpoxvirusCRMAdeathinhibitoryprotein.Isoforms5,6,7and8lackthecatalyticsiteandmayinterferewiththepro-apoptoticactivityofthecomplex. SIZE:479aminoacids;55391Da SUBUNIT:Heterotetramerthatconsistsoftwoanti-parallelarrangedheterodimers,eachoneformedbya18kDa(p18)anda10kDa(p10)subunit.InteractswithFADD,CFLARandPEA15.Isoform9interactsattheendoplasmicreticulumwithacomplexcontainingBCAP31,BAP29,BCL2and/orBCL2L1. SUBCELLULARLOCATION:Cytoplasm. TISSUESPECIFICITY:Isoforms1,5and7areexpressedinawidevarietyoftissues.Highestexpressioninperipheralbloodleukocytes,spleen,thymus,andliver.Barelydetectableinbrain,testis,andskeletalmuscle.DOMAIN:SwissProt:Q14790Isoform9containsaN-terminalextensionthatisrequiredforinteractionwiththeBCAP31complex. PTM:Generationofthesubunitsrequiresassociationwiththedeath-inducingsignalingcomplex(DISC),whereasadditionalprocessingislikelyduetotheautocatalyticactivityoftheactivatedprotease.GZMBandCASP10canbeinvolvedintheseprocessingevents.&PhosphorylateduponDNAdamage,probablybyATMorATR. DISEASE:SwissProt:Q14790#DefectsinCASP8arethecauseofcaspase-8deficiency(CASP8D)[MIM:607271].CASP8Disadisorderresemblingautoimmunelymphoproliferativesyndrome(ALPS).Itischaracterizedbylymphadenopathy,splenomegaly,anddefectiveCD95-inducedapoptosisofperipheralbloodlymphocytes(PBLs).ItleadstodefectsinactivationofT-lymphocytes,B-lymphocytes,andnaturalkillercellsleADIngtoimmunodeficiencycharacterizedbyrecurrentsinopulmonaryandherpessimplexvirusinfectionsandpoorresponsestoimmunization. SIMILARITY:BelongstothepeptidaseC14family.&Contains2DED(deatheffector)domains. |