AGGREGATION OF PROTEINS IN AGE-RELATED DISEASES

许多与年龄相关的神经退行性疾病，包括帕金森病、肌萎缩侧索硬化症和几种聚谷氨酰胺扩张性疾病，其原因是各种突变或受损多肽在神经元中的积累。这些毒性异常蛋白可以在细胞内聚集并形成大的包涵体，并且这些蛋白的聚集如何影响神经毒性在该领域正在进行讨论。最近，人们清楚地认识到，与试管中的蛋白质聚集相反，体内受损或突变多肽的聚集是一个复杂的严格调控过程，涉及许多细胞因素。该提案旨在确定促进异常蛋白质聚集的细胞成分。该建议是基于人类聚谷氨酰胺（polyQ）扩张疾病的酵母模型。这个模型使我们能够证明在polyQ聚集中有两个不同的步骤——(1)播种和(2)聚集体的生长。这些步骤需要两组不同的细胞成分，包括朊病毒构象中的朊病毒样蛋白Rnql。该模型将用于筛选影响多q聚集各个步骤的细胞突变。具有聚q聚集缺陷的突变体将被测试其执行聚集过程各个步骤的能力。然后，将确定哪些新发现的细胞因子促进polyQ

The cause of many age-related neurodegenerative disorders, including Parkinson's disease, ALS, and several polyglutamine expansion diseases, is accumulation in neurons of various mutant or damaged polypeptides. These toxic abnormal proteins can aggregate in cells and form large inclusion bodies, and there is an ongoing discussion in the field how aggregation of these proteins influences neurotoxicity. Recently it became clear that in contrast to protein aggregation in a test tube, aggregation of damaged or mutant polypeptides in vivo is a complicated tightly regulated process that involves many cellular factors. This proposal is designed to identify cellular components that promote aggregation of abnormal proteins. The proposal is based on a yeast model of human polyglutamine (polyQ) expansion diseases. This model allowed us to demonstrate that there are two distinct steps in polyQ aggregation - (1) seeding and (2) growth of aggregates. These steps require two distinct sets of cellular components, including a prion-like protein Rnql in a prion conformation. This model will be used for screens for cellular mutations that affect various steps of polyQ aggregation. Mutants with defects in polyQ aggregation will be tested for their ability to carry out various steps of the aggregation process. Then, it will be established which of the newly identified cellular factors that promote polyQ aggregation are also involved in aggregation of mutant proteins important for development of other agerelated diseases, including synphilin 1, ataxin 1 and PABP2. This work will lay the basis for further study of mechanisms of protein aggregation in neurons and aged mammalian cells.