Functional diversity of Hsp70 and J-protein chaperone systems

项目总结/摘要 维持细胞内稳态需要许多生物过程的微调平衡。蛋白 体内平衡是特别复杂的，因为它需要维持生物发生，折叠， 所有细胞蛋白质的运输和降解。一组普遍存在的蛋白质，统称为 分子伴侣，通过瞬时结合许多蛋白质，在维持蛋白质稳态中发挥积极作用。 不同的多肽。其中，Hsp 70分子伴侣/J蛋白共分子伴侣系统，其存在于所有细胞中。 主要的细胞区室是最通用的。它们不仅在体内平衡中起着关键作用 蛋白质折叠和降解的网络，而且在核心生物过程中，通常通过驱动组装和 多聚体复合物的分解。 本研究的首要目标是了解Hsp 70的属性及其J蛋白的协同作用。 伴侣蛋白，驱动它们执行不同生物角色的能力。为了做到这一点，我们将使用发达的 Hsp 70/J蛋白系统非常适合遗传和生化分析。知识 使用这些系统产生的将是便携式的其他生物体，作为热休克蛋白70和J蛋白正在研究 是高度保守的。它也将告知其他Hsp 70/J蛋白系统，这些系统不太适合实验。 我们所做的分析比我们作为模型使用的分析要多。 我们关注的是两大知识差距。首先，Hsp 70如何与生物学相关的 印刷受体.在细胞中，具有大量二级和三级结构的多肽是Hsp 70的天然多肽。 印刷受体.然而，大多数研究Hsp 70与底物相互作用循环的工作都是使用 肽，因为难以与部分折叠的蛋白质一起工作。因此，了解Hsp 70如何 与这些天然基质相互作用是有限的。第二，对行动地点的束缚是一种主要手段， J蛋白驱动Hsp 70功能。但是，这种束缚已经演变成复杂和微妙的模式， 功能直到最近才变得明显。我们将继续分析真核生物的核糖体 相关的J蛋白/Hsp 70系统。这一制度至关重要。它不仅发挥着一线作用， 通过从头蛋白质折叠，它已经涉及监测和调节翻译过程本身。

PROJECT SUMMARY/ABSTRACT Maintenance of cellular homeostasis requires a fine-tuned balance of many biological processes. Protein homeostasis is particularly intricate, because it requires maintaining balance amongst biogenesis, folding, trafficking and degradation of all cellular proteins. A group of ubiquitous proteins, referred to collectively as molecular chaperones, play active roles in maintaining protein homeostasis by transiently binding to many different polypeptides. Of these, the Hsp70 chaperone/J-protein co-chaperone systems, which are present in all major cellular compartments, are the most versatile. They play key roles not only in general homeostasis networks of protein folding and degradation, but also in core biological processes, often by driving assembly and disassembly of multimeric complexes. The overarching goal of this proposal is to understand the attributes of Hsp70, and its J-protein co- chaperones, that drive their ability to carry out diverse biological roles. To do so we will use well-developed Hsp70/J-protein systems that are exceptionally amenable to both genetic and biochemical analysis. Knowledge generated using these systems will be portable to other organisms, as the Hsp70 and J-proteins being studied are highly conserved. It will also inform other Hsp70/J-protein systems that are less amenable to experimental analysis than those we employ as models. We are focusing on two major knowledge gaps. First, how Hsp70s interact with biologically relevant substrates. In the cell, polypeptides with substantial secondary and tertiary structure are Hsp70s' natural substrates. However, most work dissecting Hsp70's cycle of interaction with substrates has been done using peptide, because of the difficulty in working with partially folded proteins. Thus, understanding of how Hsp70s interact with these natural substrates is limited. Second, tethering to sites of action is a major means by which J-proteins drive Hsp70 function. But, that such tethering has evolved into complex and nuanced modes of functionality has only recently become evident. We will continue analysis of the eukaryotic ribosome associated J-protein/Hsp70 system. This system is fundamentally important. It not only plays a first-line role in de novo protein folding, it has been implicated in monitoring and modulating the translation process itself.