Tauisafamilyofsixisoforms,derivedfromasinglegenebyalternativemRNAsplicing
1.Theyvaryinsizefrom352to441aminoacids(36.8to45.9kDa),anddifferfromoneanotherinhavingthreeorfourmicrotubulebindingrepeats
(R)of31-32aminoacidseach,andtwo,oneornoneaminoterminalinserts
(N)of29aminoacidseach2.
Taupromotestheassemblyandmaintainsthestructureofmicrotubulesinneuronalcells3,4,5.Whilethefetalbraincontainsasingleisoformoftau(Tau-352)theadultbrainhasseveralisoforms.TauisbothphosphorylatedandO-GlcNAcylated6.Thenormalbraintaucontains2-3molesofphosphate/moleoftheprotein.InAlzheimerdiseasetauishyperphosphorylated,containing3-4-foldmorephosphate/moleoftheproteinthanthenormaltau7,8andisthemajorproteinsubunitofpairedhelicalfilaments(PHF)thatformtheneurofibrillarytangles(NFT).NFTaccumulationcorrelateswiththeclinicalprogressionofAlzheimer"sdisease.Tau4G11(TA-1001)isarPeptideexclusiveTauMonoclonalAntibodythatbinds4outofthe6Tauisoforms.ItspecificallybindsTau-381,Tau-410,Tau-412,andTau-441whichallcontainatleastoneaminoterminalinsert.