Yeast prions and Hsp70 chaperones

酵母朊病毒和 Hsp70 伴侣

• 批准号: 8148684
• 负责人: Daniel Masison
• 金额: $ 40.25万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8148684
• 关键词: Molecular Chaperones; yeast prion

We are using a yeast system we constructed earlier that allows us to evaluate function of any Hsp70 isoform in yeast. We are using this system to investigate Hsp70 homologs within and across species with regard to cell growth and propagation of different prions. This very sensitive system gives us the unique ability to distinguish exquisite functional differences among nearly identical Hsp70 isoforms and provides a means to approach the problem of uncovering the underlying mechanisms. The constitutively expressed S. cerevisiae Hsp70 isoforms Ssa1 and Ssa2 are 98% identical and their stress-inducible counterparts Ssa3 and Ssa4 share 88% identity and are 80% identical to Ssa1/2. Using our system we have identified structural differences between Ssa1 and Ssa2 that underlie the differences in the way these isoforms function in both prion propagation and protein degradation. Our findings provide insight into how nearly identical Hsp70 isoforms can have distinct activities with regard to their roles in important cellular processes, and in the replication and growth processes necessary for propagation of yeast prions. Our work also reveals how functionally redundant proteins can still perform specialized tasks in the cell. Current work focuses on understanding how the structural differences influence enzymatic activities at a molecular level, which could lead to design of strategies targeting Hsp70 function in vivo in ways that would hinder amyloid accumulation. We are also using our system to investigate to what degree the structural differences contribute to differences in intrinsic Hsp70 activities or interactions with co-chaperones that regulate Hsp70.

我们正在使用先前构建的酵母系统，该系统使我们能够评估酵母中任何HSP70同工型的功能。我们正在使用该系统来研究物种内部和整个物种中的HSP70同源物，以进行不同prions的细胞生长和传播。这个非常敏感的系统使我们具有独特的能力，可以区分几乎相同的HSP70同工型之间的精美功能差异，并提供了一种方法来解决揭示潜在机制的问题。组成型表达的酿酒酵母HSP70同工型SSA1和SSA2相同98％，其应力诱导型SSA3和SSA4具有88％的身份，与SSA1/2相同80％。使用我们的系统，我们确定了SSA1和SSA2之间的结构差异，这些差异是这些同工型在prion传播和蛋白质降解中起作用的差异的基础。我们的发现提供了有关几乎相同的HSP70同工型在重要的细胞过程以及传播酵母菌prions所必需的复制和生长过程中如何具有不同活动的洞察力。我们的工作还揭示了功能多余的蛋白质如何仍能在单元格中执行专业任务。 当前的工作着重于了解结构差异如何在分子水平上影响酶促活性，这可能会导致针对体内HSP70功能的策略的设计，从而阻碍淀粉样蛋白的积累。我们还使用我们的系统来研究结构差异在多大程度上导致内在的HSP70活动或与调节HSP70的共伴侣的相互作用的差异。