TY - JOUR
T1 - Ubiquitin and microtubule-associated protein tau immunoreactivity each define distinct structures with differing distributions and solubility properties in Alzheimer brain
AU - Shaw, G.
AU - Chau, V.
PY - 1988
Y1 - 1988
N2 - Several cytoskeletal polypeptides as well as the protein ubiquitin have been implicated as components of the neurofibrillary tangles of Alzheimer disease. We have examined the relationship of ubiquitin staining with immunoreactivity for some of these proteins, both in frozen sections and in cytoskeletal fractions of Alzheimer brain material. We noted (i) antibodies specific solely for neurofilament and glial filament proteins failed to stain the fibrils stainable with ubiquitin. Tau-1 antibody stained some but not all of the ubiquitin-stained profiles; fibers staining only for tau or only for ubiquitin were also seen. (ii) The Tau-1-stained material was rather diffuse and granular, in contrast to the very sharply defined ubiquitin-positive profiles. (iii) When Tau-1 and ubiquitin stain the same fiber, Tau-1 immunoreactivity is often visualized as a diffuse cortical layer of material surrounding a core of ubiquitin immunoreactivity. (iv) The tau immunoreactivity can be almost totally removed by boiling Alzheimer brain cytoskeletal material in 2% NaDodSO4 containing a sulfhydryl reducing agent, this procedure apparently having no effect on the ubiquitin immunoreactivity. If similar material is boiled in 2% NaDodSO4 in the absence of a sulfhydryl reducing agent, the tau immunoreactivity is removed less efficiently, suggesting that tau epitopes are bound to the ubiquitin reactive material in a manner partially dependent on covalent disulfide bridges. These results show that the tau and ubiquitin distributions, both characteristic of Alzheimer disease, are qualitatively different, and that the two markers define immunologically and biochemically distinct structures.
AB - Several cytoskeletal polypeptides as well as the protein ubiquitin have been implicated as components of the neurofibrillary tangles of Alzheimer disease. We have examined the relationship of ubiquitin staining with immunoreactivity for some of these proteins, both in frozen sections and in cytoskeletal fractions of Alzheimer brain material. We noted (i) antibodies specific solely for neurofilament and glial filament proteins failed to stain the fibrils stainable with ubiquitin. Tau-1 antibody stained some but not all of the ubiquitin-stained profiles; fibers staining only for tau or only for ubiquitin were also seen. (ii) The Tau-1-stained material was rather diffuse and granular, in contrast to the very sharply defined ubiquitin-positive profiles. (iii) When Tau-1 and ubiquitin stain the same fiber, Tau-1 immunoreactivity is often visualized as a diffuse cortical layer of material surrounding a core of ubiquitin immunoreactivity. (iv) The tau immunoreactivity can be almost totally removed by boiling Alzheimer brain cytoskeletal material in 2% NaDodSO4 containing a sulfhydryl reducing agent, this procedure apparently having no effect on the ubiquitin immunoreactivity. If similar material is boiled in 2% NaDodSO4 in the absence of a sulfhydryl reducing agent, the tau immunoreactivity is removed less efficiently, suggesting that tau epitopes are bound to the ubiquitin reactive material in a manner partially dependent on covalent disulfide bridges. These results show that the tau and ubiquitin distributions, both characteristic of Alzheimer disease, are qualitatively different, and that the two markers define immunologically and biochemically distinct structures.
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U2 - 10.1073/pnas.85.8.2854
DO - 10.1073/pnas.85.8.2854
M3 - Article
C2 - 2833758
AN - SCOPUS:0023900638
SN - 0027-8424
VL - 85
SP - 2854
EP - 2858
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 8
ER -