Mechanistic Studies of the Hsp70 Chaperone System

Hsp70 伴侣系统的机理研究

• 批准号: 7637482
• 负责人: Eugene Guy Maes
• 金额: $ 2.75万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7637482
• 关键词: ATP Hydrolysis; ATPase Domain; Amyloid; Antigen Presentation; Apoptosis; Binding; Biochemical; Cell physiology; Cells; Clinical; Complex; Fluorescence Resonance Energy Transfer; Generations; Heat Stress Disorders; Heat-Shock Proteins 70; Hydrolysis; Inflammation; Ischemia; Knowledge; Life; Macromolecular Complexes; Molecular Chaperones; Molecular Conformation; Nerve Degeneration; Nervous system structure; Neurodegenerative Disorders; Nucleotides; Organism; Play; Prevention; Process; Protein Family; Protein translocation; Proteins; Reaction; Reactive Oxygen Species; Recycling; Regulation; Research Design; Resistance; Role; Staging; Stress; Structure; Synaptic Vesicles; System; Testing; Time; Toxin; analog; cancer cell; free radical oxygen; interest; intermolecular interaction; mutant; neuron loss; novel; overexpression; protein aggregation; protein complex; protein folding; protein transport; research study; stressor

DESCRIPTION (provided by applicant): The Hsp70 protein family is a diverse and ubiquitous group of molecular chaperones. There are multiple representatives of the Hsp70 family in all living organisms. Their cellular roles include assistance in protein folding, protein targeting and translocation, the assembly and disassembly of macromolecular complexes, protein transport to appropriate cellular regions, and the delivery of proteins to a proteolytic system for their disposal. The roles of Hsp70s in the prevention of protein aggregation, the refolding of denatured proteins, and the disposal of irreversibly damaged proteins are cytoprotective. Within the nervous system, Hsp70s assist in the prevention of neurodegeneration which results from amyloid aggregates, as well as play a fundamental role in synaptic vesicle recycling. Overexpression of Hsp70s protects cells against the damaging effects of a variety of stressors (i.e. inflammation, ischemia, and free radical oxygen species). Consequently, there is considerable interest in elucidating their mechanism. The basic features of the Hsp70 cycle has been known for some time. ATP binding to the ATPase domain of the Hsp70 induces an allosteric change in the protein substrate binding domain, resulting in the release of substrate, thus setting the stage for the binding of a new substrate molecule. ATP hydrolysis, and the subsequent release of Pi, results in the formation of a stable ADP*Hsp70*substrate complex. The energy released from ATP hydrolysis can be harnessed to drive protein translocation and macromolecular complex remodeling reactions. The multiple steps involved in the Hsp70 cycle are regulated by cochaperones that increase the rate of ATP hydrolysis and deliver various substrates to the Hsp70, or increase the rate ofADP/ATP exchange. However, the precise mechanisms of these processes, chiefly the allosteric mechanism, remain elusive. To alleviate these deficiencies in our understanding, I will characterize the structures of an Hsp70 in distinct, allosteric states. Both mutational and biochemical experiments will be used to investigate the observed intermolecular interactions and mechanistic hypotheses inferred from inspection of these structures.

描述（由申请人提供）：HSP70蛋白质家族是一种分子伴侣的多样化且无处不在的群体。在所有生物体中，HSP70家族都有多个代表。它们的细胞作用包括蛋白质折叠，蛋白质靶向和易位的帮助，大分子复合物的组装和拆卸，蛋白质转运到适当的细胞区域，以及将蛋白质传递到蛋白水解系统中以进行处置。 HSP70S在预防蛋白质聚集的作用，变性蛋白的重折叠以及不可逆损伤的蛋白质的处置是细胞保护的。在神经系统中，HSP70S有助于预防由淀粉样蛋白聚集体引起的神经变性，并在突触囊泡回收中起着基本作用。 HSP70S的过表达可保护细胞免受多种应激源（即炎症，缺血和自由基氧）的破坏作用。因此，阐明其机制有很大的兴趣。 HSP70周期的基本特征已有一段时间了。 ATP与Hsp70的ATPase结构域结合诱导蛋白质底物结合结构域的变构变化，从而释放底物，从而为新底物分子的结合奠定了基础。 ATP水解以及随后的PI释放，导致形成稳定的ADP*HSP70*底物复合物。可以利用从ATP水解释放的能量来驱动蛋白质易位和大分子复合物重塑反应。 HSP70循环中涉及的多个步骤受联合酮的调节，这些步骤会增加ATP水解速率并将各种底物输送到HSP70，或增加ADP/ATP交换的速率。但是，这些过程的确切机制（主要是变构机制）仍然难以捉摸。为了减轻我们的理解中这些缺陷，我将以不同的变构状态来表征HSP70的结构。突变和生化实验都将用于研究观察这些结构所推论的观察到的分子间相互作用和机械假设。