title: Accumulation of aspartic acid421- and glutamic acid391-cleaved tau in neurofibrillary tangles correlates with progression in Alzheimer disease.
abstract: Truncations of tau protein at aspartic acid421 (D421) and glutamic acid391 (E391) residues are associated with neurofibrillary tangles (NFTs) in the brains of Alzheimer disease (AD) patients. Using immunohistochemistry with antibodies to D421- and E391-truncated tau (Tau-C3 and MN423, respectively), we correlated the presence of NFTs composed of these truncated tau proteins with clinical and neuropathologic parameters in 17 AD and 23 non-AD control brains. The densities of NFTs composed of D421- or E391-truncated tau correlated with clinical dementia index and Braak staging in AD. Glutamic acid391 tau truncation was prominent in the entorhinal cortex, whereas D421 truncation was prominent in the subiculum, suggesting that NFTs composed of either D421- or E391-truncated tau may be formed mutually exclusively in these areas. Both truncations were associated with the prevalence of the apolipoprotein E epsilon4 allele. By double labeling, intact tau in NFTs was commonly associated with D421-cleaved tau but not with E391-truncated tau; D421-cleaved tau was never associated with E391-truncated tau. These results indicate that tau is not randomly proteolyzed at different domains, and that proteolysis occurs sequentially from the C-terminus to inner regions of tau in AD progression. Identification of NFTs composed of tau at different stages of truncation may facilitate assessment of neurofibrillary pathology in AD.
authors.affiliation: Department of Cell Biology, Center of Research and Advanced Studies of the IPN, Mexico City, Mexico.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Basurto-Islas
authors.forename: Jose
authors.initials: J
authors.lastname: Luna-Muñoz
authors.forename: Angela L
authors.initials: AL
authors.lastname: Guillozet-Bongaarts
authors.forename: Lester I
authors.initials: LI
authors.lastname: Binder
authors.forename: Raul
authors.initials: R
authors.lastname: Mena
authors.forename: Francisco
authors.initials: F
authors.lastname: García-Sierra
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D000595:Amino Acid Sequence / Q000502:physiology; D053327:Apolipoprotein E4 / Q000235:genetics / Q000378:metabolism; D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism*; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005838:Genotype; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008970:Molecular Weight; D016874:Neurofibrillary Tangles / Q000378:metabolism* / Q000473:pathology; D010447:Peptide Hydrolases / Q000378:metabolism; D011237:Predictive Value of Tests; D017434:Protein Structure, Tertiary; D040901:Proteomics / Q000379:methods; D012720:Severity of Illness Index; D016875:tau Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D053327:Apolipoprotein E4; D016875:tau Proteins; D001224:Aspartic Acid; D018698:Glutamic Acid; D010447:Peptide Hydrolases