Molecular mechanisms of transthyretin amyloidosis

许多使人衰弱的人类疾病与细胞外错误折叠和聚集有关 形成富含β折叠的纤维状沉积物。有相当多的证据 这一过程是由天然结构的局部展开开始的， 淀粉样中间体。聚集然后通过成核-生长或下坡进行 聚合机理尽管它们在淀粉样蛋白生成中起着关键作用，但影响淀粉样蛋白的动力学 在聚集和重折叠途径之间的划分，对聚合物的结构知之甚少。 淀粉样蛋白生成中间体，因为它们具有很强的聚集倾向。的目标 目前的建议是应用最先进的NMR方法来阐明基本的分子 甲状腺素运载蛋白淀粉样变性相关事件。甲状腺素运载蛋白淀粉样变性与许多 神经变性疾病和心肌病。甲状腺素运载蛋白的错误折叠和聚集 导致周围神经和心脏的纤维沉积。野生型蛋白质的沉积是年龄 相关，而与基因突变相关的家族性疾病， 四级和/或三级结构是早期发生的。这项研究将提供新的 深入了解野生型甲状腺素运载蛋白聚集的基本分子机制 并且通过其家族性突变使天然甲状腺素运载蛋白四聚体不稳定，并驱动 聚合级联实时19 F NMR将用于绘制以下物质的动力学聚集景观： 野生型和致病性变体甲状腺素运载蛋白，表征和量化 聚集途径上积累的中间体，并检查抑制机制 由小分子和肽组成。多维核磁共振实验将用于阐明 促进四聚体解离的交替构象状态的结构和动力学， 以及在聚集途径上形成的细胞毒性单体和寡聚体中间体， 促进聚集和原纤维生长。这项研究将促进我们对 引发四聚体解离并促进进入和 这导致野生型人和野生型人的淀粉样蛋白形成的聚集级联反应向下进展， 甲状腺素运载蛋白和致病性变体。

Many debilitating human diseases are associated with the extracellular misfolding and aggregation of globular proteins to form fibrillar deposits that are rich in β-sheet. There is considerable evidence that the process is initiated by local unfolding of the native structure to form aggregation-prone amyloidogenic intermediates. Aggregation then proceeds via nucleation-growth or downhill polymerization mechanisms. Despite their key role in amyloidogenesis, influencing the kinetic partitioning between aggregation and refolding pathways, very little is known about the structure of amyloidogenic intermediates because of their strong propensity to aggregate. The goals of the present proposal are to apply state-of-the-art NMR methods to elucidate the fundamental molecular events involved in transthyretin amyloidosis. Transthyretin amyloidosis is associated with numerous neurodegenerative diseases and cardiomyopathies. Misfolding and aggregation of transthyretin leads to fibrous deposits in the peripheral nerves and heart. Deposition of wild type protein is age related, whereas the familial diseases associated with genetic mutations that destabilize the quaternary and/or tertiary structure are early onset. The proposed research will provide novel insights into the fundamental molecular mechanisms by which wild type transthyretin aggregates and by which familial mutations destabilize the native transthyretin tetramer and drive the aggregation cascade. Real-time 19F NMR will be used to map the kinetic aggregation landscape of wild type and pathogenic variant transthyretin, characterize and quantify the population of intermediates that accumulate on the aggregation pathway, and examine mechanisms of inhibition by small molecules and peptides. Multidimensional NMR experiments will be utilized to elucidate the structure and dynamics of an alternate conformational state that promotes tetramer dissociation, and of cytotoxic monomeric and oligomeric intermediates, formed on the aggregation pathway, that promote aggregation and fibril growth. This research will advance our understanding of the underlying molecular events that initiate tetramer dissociation and promote entry into and progression down the aggregation cascade that leads to amyloid formation by both wild type human transthyretin and pathogenic variants.