Hsp110 protein chaperone function in yeast

Hsp110 蛋白伴侣在酵母中的功能

• 批准号: 7856487
• 负责人: KEVIN ANTHONY MORANO
• 金额: $ 4.44万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-15 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7856487
• 关键词: ATP phosphohydrolase; ATPase Domain; Address; Bacteria; Binding; Biochemical; Biogenesis; Biological Assay; Cells; Cellular biology; Client; Collaborations; Complement; Complex; Coupling; Eukaryota; 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; 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

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 HspQO, 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. Wetherefore 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.

热休克蛋白(HSPs)在细胞生物学中具有双重作用；它们是抵御 细胞毒性应激，并在正常生长条件下紧密整合到信号和调控通路中 条件。热休克蛋白的一个子集，包括Hsp70和HspQO，作为分子伴侣，可能是 在底物蛋白质生命周期的多个阶段，从生物发生、定位和 稳定性，到活化和降解。蛋白伴侣在许多病理生理过程中被诱导 包括缺血和肿瘤发生在内的条件，并已知促进稳定性和活性 癌蛋白，如v-src激酶和p53肿瘤抑制因子。Hsp110级伴侣是一种 Hsp70相对知之甚少，存在于所有真核生物中，具有未知的组织特异性亚型 在人类身上起作用。我们的长期目标是阐明这个伴侣蛋白家族的细胞角色。这个 面包酵母Hsp110同源基因是由SSE1和SSE2基因编码的，人们对它们的了解很少 功能。我们发现Sse1在体内以异源二聚体的形式存在，与胞浆中的Hsp70 SSA和 SSB，并且Sse1是Hsp90伴侣系统信号转导活动所必需的。因此，我们 假设Sse1，进而延伸到哺乳动物的Hsp110伴侣，可能主要作为一种 热休克蛋白70活性的调节剂。这一建议试图获得对细胞角色的机械性理解 问两个具体的问题：1)Sse1是如何与 酵母Hsp70 Ssa1和2)Sse1如何参与Hsp90的信号转导？在第一个目标中，我们 最终将使用纯化的伴侣蛋白确定相互作用部位和Sse1对Hsp70的调节 Sse1对体外蛋白质折叠的破译作用。我们将在体内补充这些实验 测定Sse1对Ssa1依赖过程的贡献。在第二个目标中，我们将 确定Sse1在Hsp90底物折叠周期中的作用阶段以及对Hsp90底物折叠周期的具体影响 底物成熟使用的模型客户蛋白糖皮质激素受体。最后，我们将应用这些 了解Sse1与Hsp90合作是如何通过以下方式实现热休克存活所需的发现 在细胞完整性途径中通过SLt2 MAP激酶调节信号。这些调查路线在 酵母将作为一个模型来预测Hsp110可能促进哺乳动物细胞的哪些过程。