Alzheimer disease specific phosphoepitopes of Tau interfere with assembly of tubulin but not binding to microtubules
Alzheimer disease specific phosphoepitopes of Tau interfere with assembly of tubulin but not binding to microtubules
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DOI：
10.1096/fj.08-121590
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发表时间：
2009-04-01
期刊：
影响因子：
4.8
通讯作者：
Landrieu, Isabelle
中科院分区：
文献类型：
--
作者：
Amniai, Laziza;Barbier, Pascale;Landrieu, Isabelle
在阿尔茨海默病（AD）影响的神经元中，Tau蛋白被发现处于聚集和过度磷酸化状态。一种常见的假设是Tau过度磷酸化导致其从微管表面解离，从而导致微管（MT）的分解和未结合的Tau的聚集。我们评估了Tau磷酸化对微管蛋白组装和MT结合的影响。我们表明，细胞周期蛋白依赖性激酶2/细胞周期蛋白A3激酶复合物可以产生AT 8和AT 180 AD特异性磷酸化表位，并使用NMR光谱定性和定量验证我们的样品的磷酸含量。两种表位的同时存在使Tau在其中Tau是组装过程的驱动力的条件下的微管蛋白组装能力失效，但是，当MT组装由增加的微管蛋白浓度驱动时，不会抑制MT组装。当与分离的MT结合重复序列（Kd = 0.3 μ M）相比时，磷酸化Tau保留了对预先形成的MT的实质性亲和力（Kd = 11 nM），表明磷酸化的富含脯氨酸的区域仍然参与结合事件。因此，我们的结果表明，AT 8/AT 180表位处的唯一磷酸化虽然导致Tau的功能缺陷，但不足以使其从MT表面解离并随后聚集，如在AD中观察到的。阿姆尼埃湖，Barbier，P.，西伦，A.，Wieruszeski，J. M.，Peyrot，V.，Lippens，G.，兰德里欧岛Tau的阿尔茨海默病特异性磷酸化表位干扰微管蛋白的组装，但不与微管结合。FASEB J. 23，1146-1152（2009）
In Alzheimer disease (AD)-affected neurons, the Tau protein is found in an aggregated and hyperphosphorylated state. A common hypothesis is that Tau hyperphosphorylation causes its dissociation from the microtubular surface, with consequently a breakdown of the microtubules (MTs) and aggregation of the unbound Tau. We evaluated the effect of Tau phosphorylation on both tubulin assembly and MT binding. We show that the cyclin-dependent kinase 2/cyclin A3 kinase complex can generate the AT8 and AT180 AD-specific phospho-epitopes and use NMR spectroscopy to validate qualitatively and quantitatively the phospho content of our samples. The simultaneous presence of both epitopes disables the tubulin assembly capacity of Tau in conditions whereby Tau is the driving force for the assembly process but does not, however, inhibit MT assembly when the latter is driven by an increased tubulin concentration. When compared to the isolated MT binding repeats (K-d = 0.3 mu M), the phospho-Tau retains a substantial affinity for preformed MTs (K-d = 11 nM), suggesting that the phosphorylated proline-rich region still participates in the binding event. Our results hence indicate that the sole phosphorylation at the AT8/AT180 epitopes, although leading to a functional defect for Tau, is not sufficient for its dissociation from the MT surface and subsequent aggregation as observed in AD.-Amniai, L., Barbier, P., Sillen, A., Wieruszeski, J.-M., Peyrot, V., Lippens, G., Landrieu, I. Alzheimer disease specific phosphoepitopes of Tau interfere with assembly of tubulin but not binding to microtubules. FASEB J. 23, 1146-1152 (2009)