本项目针对目前国际上分子伴侣对朊病毒聚集调控机制研究的难点，以酵母朊病毒[PSI+]和酵母细胞质中Hsp70家族成员Ssa1p为研究对象，在原有的生物学研究方法中，引入分子动力学模拟技术和新型筛选模型，并结合一定的结构生物学实验验证，1）高效筛选影响酵母朊病毒[PSI+]聚集的Ssa1p突变体；2）研究Ssa1p突变体的结构变化对其自身功能，以及Ssa1p与辅助伴侣Hsp40、NEF间相互作用的影响规律及动力学特性；3）通过与Hsp70家族Ssa1p同源蛋白关键位点的对比研究，获得Ssa1p对[PSI+]聚集调控的共性及特异性特征。最终综合以上研究结果，对Ssa1p调控酵母朊病毒[PSI+]聚集的特异性机制进行系统科学的预测。本研究在理论和方法上将为分子伴侣调控朊病毒聚集的分子机制研究带来重要的创新，并在应用上将有助于发现新的治疗朊病毒疾病的生物途径、开发潜在的药物作用靶点。

The mechanism of molecular chaperones in prion aggregation is one big challenge in the research of prion disease around the globe. The discovery that yeast possesses proteins that propagate in a similar manner to mammalian prions has allowed detailed genetic and biochemical analysis to identify factors that influence prion aggregation. One key modulator of prion aggregation is the Hsp70 molecular chaperone system. In this proposal we plan to use the well established [PSI+] yeast prion system and to apply a combination of computational, genetics, biochemistry, structural and molecular techniques to elucidate the key molecular features of Ssa1p (yeast cytosolic Hsp70) role in prion aggregation. Specifically, three main objectives of this work are i) To effectively screen the Ssa1p mutant which influence yeast prion [PSI+] aggregation; ii) To characterize the structure-function relationship of Ssa1p mutants, and identify important amino acid residues between Ssa1p and its cofactors (e.g. Hsp40, NEF) that act as key regulators of Hsp70 function; iii) To extend these studies into closely related Hsp70 variants, and assess whether our key findings are applicable across the Hsp70 family and specific structure-function relationship among Hsp70 family members on yeast prion aggregation. Carrying out this project will bring technical innovation to the molecular chaperone and prion study. Our finding will not only contribute to the final unriddling mechanism of chaperone Hsp70 in yeast prion aggregation, but also will inform chaperone and prion interactions in higher organisms. Moreover, it will be benefit for finding novel target position for anti-prion drugs.