Investigation of the yeast prion factor [PSI+]

项目摘要 不同细胞蛋白错误折叠成淀粉样聚集体与非淀粉样蛋白相关 传染性神经退行性疾病，包括阿尔茨海默氏症、亨廷顿氏症和帕金森氏症，以及 传染性普恩病毒疾病，如疯牛、鹿的慢性消瘦和人类的克雅氏病。对于每个 在这些疾病中，相关的蛋白质聚集体(种子)吸引其正常构象错误折叠和连接 总体而言。简单的真核生物酵母中的某些蛋白质同样可以错误折叠成传染性淀粉样蛋白。 聚集体，而这些聚集体会引起表观遗传变异。在这项提议中，酵母菌遗传学和 分子生物学被用来研究蛋白质如何错误折叠成类淀粉样聚集体及其后果。 这是细胞的错误折叠。酵母与人类细胞之间的广泛相似性使酵母 在理解人类疾病方面做出重大贡献的模型，意味着这些研究很可能 与人类错误折叠的聚集蛋白有关。 由于大多数人类蛋白质错误折叠疾病发生时不会受到任何外部种子的感染，因此目标I 重点研究围绕自发细胞淀粉样蛋白形成的分子机制。这些问题 讨论的问题是：新出现的Pron聚集体在细胞中最先出现在哪里，还有哪些其他蛋白质 与它们相关的，以及先前存在的普鲁恩如何促进异源生物的从头出现 普里恩？目的我还验证了哺乳动物亨廷顿蛋白的酵母同系物Sla2与 蛋白质，促进现有的Prion与异源Prion的从头凝聚杂交的能力 蛋白质，通过与种子和要播种的蛋白质结合，从而将它们放在非常接近的位置。 有趣的是，人类和酵母蛋白都可以形成多种不同的淀粉样聚集体。 在结构上不同，并导致不同的表型或疾病病理，即使氨基酸 这些蛋白质的序列是相同的。AIM II确定结合和/或繁殖所需的蛋白质 几种普恩病毒及其变种。此外，同一蛋白的两个变异体的固体核磁共振结构 将在合作者的帮助下确定。通过比较异源Prion以及不同的 相同的普恩变种，对所有普恩的维持和感染性可能是共同的因素，以及 因此，应提供有用的药物靶点，将被确定。 虽然淀粉样蛋白的形成与疾病有关，但实际的病理原因尚不清楚。在《目标3》中， 对两种对酵母造成毒性的普恩的遗传和分子研究将有助于确定有毒物种。 最后，酵母蛋白不仅作为人类疾病的模型很重要，还因为它们表明 在蛋白质构象水平上而不是在蛋白质构象水平上操作的重要的遗传变异新机制 核酸。在Aim IV中，一个引人入胜的问题是，普恩病毒是否有时能为宿主细胞提供 本课程探讨了这种优势，以及在哺乳动物中也可能存在这样的优势蛋白的可能性。

Project Summary The misfolding of different cellular proteins into amyloid-like aggregates is associated with non- infectious neurodegenerative diseases including Alzheimer's, Huntington's and Parkinson's, as well as with the infectious prion diseases e.g. Mad Cow, Chronic Wasting in deer and Creutzfeldt-Jacob in humans. For each of these diseases, the associated protein aggregate ("seed') attracts its normal conformers to misfold and join the aggregate. Certain proteins in the simple eukaryote yeast, can likewise misfold into infectious amyloid aggregates, and these aggregates cause epigenetic variation. In this proposal, the power of yeast genetics and molecular biology is used to study how proteins misfold into amyloid-like aggregates and the consequences of this misfolding for the cell. The extensive similarity between yeast and human cells, which has enabled yeast models to make significant contributions in understanding human disease, implies that these studies will likely be relevant to misfolded aggregating proteins in humans. Since most human protein misfolding diseases occur without infection by any external seed, Aim I focuses on the molecular mechanisms surrounding spontaneous cellular amyloid formation. The questions addressed are: where do newly appearing prion aggregates first arise in cells, what other proteins are associated with them, and how do pre-existing prions enhance the de novo appearance of heterologous prions? Aim I also tests the hypothesis that Sla2, the yeast homolog of the mammalian huntingtin interacting protein, facilitates the ability of existing prions to cross-seed the de novo aggregation of heterologous prion proteins, by binding to both the seed and protein to be seeded, thereby placing them in close proximity. Interestingly, human and yeast prion proteins can each form multiple variants of amyloid aggregates that differ in structure and cause distinct phenotypes or disease pathologies, even though the amino acid sequences of the proteins are identical. Aim II identifies proteins bound to, and/or required for, the propagation of several prions and their variants. In addition, solid-state NMR structures of two variants of the same prion will be determined with the help of collaborators. By comparing heterologous prions, as well as different variants of the same prion, factors likely to be common to the maintenance and infectivity of all prions and that should therefore provide useful drug targets, will be identified. While amyloid formation is associated with disease, the actual cause of pathology is unclear. In Aim III, genetic and molecular studies of two prions that cause toxicity in yeast will help define the toxic species. Finally, yeast prions are important not only as a model for human disease, but also because they suggest an important new mechanism of genetic variation operating at the level of protein conformation rather than nucleic acids. In Aim IV the fascinating question of whether prions can sometimes provide the host cell with an advantage is explored, along with the possibility that such advantageous prions may also exist in mammals.