Osteoprotegerin(OPG)orosteoclastogenesisinhibitoryfactor(OCIF),aproductoftheTNFRSF11Bgenelocatedinchromosome8q24,isamemberoftheTNFreceptorsuperfamilythatplaysakeyroleinboneremodeling.
HumanOPGisa401aminoacidsecretedglycoproteinthatexistsnaturallyaseithera120kDAdisulfide-linkedhomodimeror60kDamonomer.OPGisactiveaseitheramonomerordimer,withthedimershowingmorepotentbioactivity.UnlikemostmembersoftheTNFreceptorsuperfamily,OPGaparentlyexistsonlyinasolubleformasadecoyreceptorforitsligands,RANKL(TNFSF11,OPGL,ODF,TRANCE)andTRAIL.
Human
OPGshares85%and86%aminoacididentitytomouseandratOPGrespectively.Inhumanadults,OPGmRNAishighlyexpresedinvarioustissues,e.g.bone,skin,liver,stomach,intestine,heart,brainandlung.
OsteoprotegerininhibitsthebindingofRANKLtoRANK(osteoclastdifferentiationandactivationreceptor,ODAR)ontheosteoclastsurfaceandthus,OPGisanaturalantago
NISTtoRANKL-inducedosteoclastogenesisandboneresorption.SinceOPGexhibitsaninhibitoryeffectonosteoclasts,itactsasasolublefactorintheregulationofbonemass.
OsteoclastformationactivitymaybemonitoredprincipallybydeterminationoftheconcentrationratioofRANKL/OPG.Alterationofthisratiomaybethecauseofbonelossinmanyimbalancesinbonemetabolismsuchasosteoporosis,osteopetrosis,hypercalcemia,metastaticosteolyticlesionsandrheumaticbonedegradation.
ForconcretedatapleaseconsulttheInstructionforUseinthedownloadboxontherightside.