C-terminal inhibition of tau assembly in vitro and in Alzheimer's disease.
C-terminal inhibition of tau assembly in vitro and in Alzheimer's disease.
复制标题
DOI：
--
复制
发表时间：
2000-11
影响因子：
4
通讯作者：
Aida Abraha;N. Ghoshal;T. C. Gamblin;V. Cryns;Robert W. Berry;J. Kuret;L. Binder
中科院分区：
文献类型：
--
作者：
Aida Abraha;N. Ghoshal;T. C. Gamblin;V. Cryns;Robert W. Berry;J. Kuret;L. Binder
阿尔茨海默病（AD）部分地由tau聚合成成对的螺旋和直丝（PHF/SF）来定义，所述成对的螺旋和直丝（PHF/SF）一起构成退化脑区域中的纤维状病理。这些纤维中的大部分tau蛋白通过磷酸化修饰。此外，一个子集似乎也被蛋白水解截短，导致其C末端的去除。识别在S（396/404）处磷酸化或在E（391）处截短的tau蛋白的抗体不染色对照脑，但在疾病过程的非常早期染色脑切片。我们模拟这些磷酸化和截短事件，通过创建假磷酸化和缺失突变体来自全长重组人tau蛋白亚型（ht 40），包含N-末端外显子2和3和所有四个微管结合重复。体外组装实验表明，这两种修饰都大大提高了tau细丝形成的速率，并且截短也增加了形成的聚合物的质量。从tau的C末端去除少至12个或多至121个氨基酸大大增加了tau聚合的速率和程度。然而，从第三个微管结合重复序列中缺失另外7个氨基酸（314）DLSKVTS（320）导致tau在体外形成细丝的能力丧失。这些结果表明，只有部分微管结合域（重复序列1，2和3的一小部分）是至关重要的tau聚合。此外，tau蛋白的C末端明显抑制组装过程;这种抑制可以通过位点特异性磷酸化部分逆转，并通过从S（320）到分子末端的各个位点的截短事件完全去除。
Alzheimer's disease (AD) is, in part, defined by the polymerization of tau into paired helical and straight filaments (PHF/SFs) which together comprise the fibrillar pathology in degenerating brain regions. Much of the tau in these filaments is modified by phosphorylation. Additionally, a subset also appears to be proteolytically truncated, resulting in the removal of its C terminus. Antibodies that recognize tau phosphorylated at S(396/404 )or truncated at E(391) do not stain control brains but do stain brain sections very early in the disease process. We modeled these phosphorylation and truncation events by creating pseudo-phosphorylation and deletion mutants derived from a full-length recombinant human tau protein isoform (ht40) that contains N-terminal exons 2 and 3 and all four microtubule-binding repeats. In vitro assembly experiments demonstrate that both modifications greatly enhance the rates of tau filament formation and that truncation increases the mass of polymer formed, as well. Removal of as few as 12 or as many as 121 amino acids from the C terminus of tau greatly increases the rate and extent of tau polymerization. However, deletion of an additional 7 amino acids, (314)DLSKVTS(320), from the third microtubule-binding repeat results in the loss of tau's ability to form filaments in vitro. These results suggest that only part of the microtubule-binding domain (repeats 1, 2 and a small portion of 3) is crucial for tau polymerization. Moreover, the C terminus of tau clearly inhibits the assembly process; this inhibition can be partially reversed by site-specific phosphorylation and completely removed by truncation events at various sites from S(320) to the end of the molecule.