Hsp40 and Stress Protection

描述（由申请人提供）： 本项目的长期目标是利用酵母S。酿酒酵母作为模型系统，以确定胞质Hsp40 Sis1和Ydj1与Hsp70 Ssal（Ssal）作用以保护细胞免受变性生理应激如热休克的机制。热休克反应的标志是伴侣蛋白表达的快速诱导和蛋白质合成的全面抑制。这些事件的发生是为了防止非天然蛋白质的积累并抑制蛋白质聚集。Hsp40通过结合非天然蛋白质并将其递送至HspT0的多肽结合位点来抑制蛋白质聚集。在目标1中，我们提出了一系列实验，旨在确定Hsp40结合底物的机制。在目标2中，我们将研究如何结合到热休克蛋白40的变性蛋白质被传递到热休克蛋白70，以促进蛋白质重折叠。Hsp40家族成员的另一个特征是它们已经进化成具有不同的结构域结构，并且可以靶向Hsp70以催化不同的细胞反应。我们已经证明，Ydjl和Sis1在胞质溶胶中的功能是指导Ssal促进蛋白质代谢的不同方面。在目标3和目标4中，我们提出了一系列Ydjl和Sis1之间的结构域交换实验，这些实验旨在定义Hsp70 s细胞功能的指定规则，这些研究的结果将定义Hsp40 s与Hsp70一起保护细胞免受生理应激的基本机制。

DESCRIPTION (provided by applicant): The long-term objective of this project is to utilize the yeast S. cerevisiae as a model system to determine the mechanism by which the cytosolic Hsp40s Sis1 and Ydjl act with Hsp70 Ssal (Ssal) to protect cells from denaturing physiological stresses such as heat-shock. The hallmark of the heat-shock response is the rapid induction of chaperone protein expression and the global suppression of protein synthesis. These events occur to prevent the accumulation of non-native proteins and suppress protein aggregation. Hsp40s function to suppress protein aggregation by binding non-native proteins and delivering them to the polypeptide binding site of HspT0. In aim 1, we propose a series of experiments that are designed to determine the mechanism for substrate binding by Hsp40s. In aim 2, we will investigate how denatured proteins that are bound to Hsp40 are delivered to Hsp70 to facilitate protein refolding. An additional feature of Hsp40 family members is that they have evolved to have different domain structures and can target Hsp70 to catalyze different cellular reactions. We have demonstrated that the Ydjl and Sis1 function in the cytosol to direct Ssal to facilitate different aspects of protein metabolism. In Aim 3 and Aim 4 we propose a series of domain swap experiments between Ydjl and Sis1 that are designed to define the rules by which Hsp70s cellular functions are specified.The outcome of these studies will define basic mechanisms by which Hsp40s function with Hsp70 to protect cells from physiological stress.