Hsp110 protein chaperone function in yeast

Hsp110 蛋白伴侣在酵母中的功能

• 批准号: 7210539
• 负责人: KEVIN ANTHONY MORANO
• 金额: $ 25.92万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7210539
• 关键词: ATP phosphohydrolase; ATPase Domain; Address; Bacteria; Binding; Biochemical; Biogenesis; Biological Assay; Cells; Cellular biology; Class; Client; Collaborations; Complement; Complex; Condition; Coupling; Eukaryota; Eukaryotic Cell; Family; Genes; Glucocorticoid Receptor; Growth; Heat shock proteins; Heat-Shock Response; Homologous Gene; Human; Hydrolysis; In Vitro; Investigation; Ischemia; Mammalian Cell; Mediating; Mitogen-Activated Protein Kinases; Modeling; Molecular; Molecular Chaperones; Nucleotides; Oncogene Proteins; Pathway interactions; Peptides; Play; Process; Protein Isoforms; Protein p53; Proteins; Range; Regulation; Regulatory Pathway; Relative (related person); Role; Saccharomyces cerevisiae; Signal Pathway; Signal Transduction; Site; Staging; Stress; System; Testing; Tissues; Yeasts; base; cytotoxic; heat-shock proteins 110; in vivo; novel; protein folding; receptor expression; research study; src-Family Kinases; structure-specific endonuclease I; tumorigenesis; v-src Oncogenes

DESCRIPTION (provided by applicant): Heat shock proteins (Hsps) play dual roles in cellular biology; they are the first line of defense against cytotoxic stresses, and are tightly integrated into signaling and regulatory pathways under normal growth conditions. A subset of Hsps, including Hsp70 and Hsp90, act as molecular chaperones, and may be required at multiple stages during a substrate protein's lifetime, ranging from biogenesis, localization, and stability, to activation and degradation. Protein chaperones are induced during numerous pathophysiological conditions including ischemia and tumorigenesis, and are known to facilitate stability and activity of oncoproteins such as v-src kinase and the p53 tumor suppressor. The Hsp110 class of chaperones is a poorly understood Hsp70 relative and is present in all eukaryotes, with tissue-specific isoforms of unknown function in humans. Our long-term objective is to elucidate the cellular roles of this chaperone family. The baker's yeast Hsp110 homolog is encoded by the SSE1 and SSE2 genes, and little is known about their function. We have discovered that Sse1 exists as a heterodimer in vivo with the cytosolic Hsp70s Ssa and Ssb, and that Sse1 is required for signal transduction activity of the Hsp90 chaperone system. We therefore hypothesize that Sse1, and by extension the mammalian Hsp110 chaperone, may function primarily as a modulator of Hsp70 activity. This proposal seeks to gain a mechanistic understanding of the cellular roles of Hsp110 chaperones by asking two specific questions: 1) How does Sse1 operate in partnership with the yeast Hsp70 Ssa1 and 2) How does Sse1 participate in signal transduction with Hsp90? In the first aim we will determine interaction sites and regulation of Hsp70 by Sse1 using purified chaperones, ultimately deciphering effects of Sse1 on protein folding in vitro. We will complement these experiments with in vivo assays to determine the contribution of Sse1 to Ssa1-dependent processes. In the second aim, we will determine both the stage at which Sse1 acts in the Hsp90 substrate folding cycle, and specific effects on substrate maturation using the model client protein glucocorticoid receptor. Finally we will apply these findings to understand how Sse1 in collaboration with Hsp90 is required for heat shock survival by modulating signaling through the Slt2 MAP kinase in the cell integrity pathway. These lines of investigation in yeast will serve as a model for predicting which processes Hsp110 may facilitate in mammalian cells.

描述（由申请人提供）：热休克蛋白（Hsps）在细胞生物学中发挥双重作用;它们是抵御细胞毒性应激的第一道防线，并在正常生长条件下紧密整合到信号传导和调节途径中。热休克蛋白的一个子集，包括热休克蛋白70和热休克蛋白90，作为分子伴侣，并可能需要在多个阶段，在底物蛋白的生命周期，从生物发生，定位，稳定性，活化和降解。蛋白伴侣在包括缺血和肿瘤发生在内的许多病理生理条件下被诱导，并且已知促进癌蛋白如v-src激酶和p53肿瘤抑制因子的稳定性和活性。Hsp 110类分子伴侣是一个知之甚少的Hsp 70相对，并存在于所有真核生物中，在人类中具有未知功能的组织特异性亚型。我们的长期目标是阐明这个分子伴侣家族的细胞作用。面包酵母Hsp 110同源物由SSE 1和SSE 2基因编码，但对它们的功能知之甚少。我们已经发现，Sse 1存在作为异源二聚体在体内与胞质Hsp 70的Ssa和Ssb，和Sse 1所需的Hsp 90分子伴侣系统的信号转导活性。因此，我们假设Sse 1，并通过扩展的哺乳动物Hsp 110分子伴侣，可能主要作为一个调制器的Hsp 70活性。该建议旨在通过提出两个具体问题来获得对Hsp 110分子伴侣的细胞作用的机械理解：1）Sse 1如何与酵母Hsp 70 Ssa 1合作; 2）Sse 1如何参与Hsp 90的信号转导？在第一个目标中，我们将确定相互作用的网站和调节Hsp 70的Sse 1使用纯化的分子伴侣，最终破译的影响Sse 1蛋白质折叠在体外。我们将补充这些实验，在体内测定，以确定Sse 1的贡献Ssa 1依赖的过程。在第二个目标中，我们将确定Sse 1在Hsp 90底物折叠周期中起作用的阶段，以及使用模型客户蛋白糖皮质激素受体对底物成熟的具体影响。最后，我们将应用这些研究结果来了解Sse 1与Hsp 90的合作是如何通过调节细胞完整性途径中的Slt 2 MAP激酶来实现热休克存活所需的。酵母中的这些研究路线将作为预测Hsp 110可能促进哺乳动物细胞中哪些过程的模型。