ER Chaperone Availability in Cells During Homeostasis and Misfolded Protein Stres

稳态和错误折叠蛋白质应激期间细胞内内质网伴侣的可用性

• 批准号: 7932026
• 负责人: Erik L. Snapp
• 金额: $ 32.25万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-14 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7932026
• 关键词: Apoptotic; Binding; Biochemical; Biochemistry; Biosensor; Buffers; Cell Survival; Cells; Cessation of life; Complex; Endoplasmic Reticulum; Environment; Exhibits; Failure; Feedback; Fluorescence; Fluorescence Microscopy; Gel; Genetic screening method; Goals; Health; Heat shock proteins; Homeostasis; Hour; Human; Label; Left; Life; Maintenance; Measures; Methods; Microscopy; Modeling; Molecular; Molecular Chaperones; Nature; Operating System; Organism; Pathway interactions; Phase; Physiologic pulse; Prevalence; Process; Protein Binding; Proteins; Publishing; Quality Control; Radioactive; Reporter; Resolution; Stress; System; Time; Tube; base; biological adaptation to stress; cellular imaging; coping; endoplasmic reticulum stress; novel; protein folding; protein function; protein misfolding; public health relevance; research study; response; restoration; secretory protein; stress protein; stressor

DESCRIPTION (provided by applicant): Our goal is to elucidate the physical and molecular basis of homeostasis and misfolded protein stress in the endoplasmic reticulum (ER). Correct folding and quality control of secretory proteins by ER chaperones is essential for the viability of cells and organisms. Failure to correctly fold proteins results in loss of protein function, can activate the Unfolded Protein Response (UPR), and stimulate apoptotic death. Whether chaperones are sufficiently available for nascent or misfolded proteins under different environmental conditions is critical to understanding chaperone function. The ER chaperone network at steady state could be buffered with redundancy and an excess of chaperones or the network could be operating at the edge of protein folding capacity. The nature of the ER chaperone network has deep implications for how the ER senses and copes with misfolded protein stress. A system operating at capacity leaves little room for error, will have an explicit threshold for stress, and is likely to exhibit biphasic extremes. In contrast, stress and homeostasis could exist as a gradient of states in a buffered and redundant system. Small perturbations in folding requirements could be sensed and responded to, without upsetting the global folding environment. We hypothesize that the complexity and buffering capacity of the ER chaperone network regulates activation of ER stress pathways and maintenance of ER homeostasis. Chaperone network complexity will depend on the distribution, dynamics, organization, and occupancy of lumenal ER chaperones. While genetics and test-tube biochemistry have helped define the folding activities of chaperones, it remains poorly understood how ER chaperones encounter and interact with their substrates in cells in real time. We will employ biochemical, pharmacologic, and quantitative single cell fluorescence microscopy methods to establish a model of the ER chaperone network with exquisite spatio-temporal resolution. Our biophysical systems approach will define the hierarchy of the ER chaperone network during homeostasis and misfolded protein stress. PUBLIC HEALTH RELEVANCE The processes of correct secretory protein folding and quality control are vital for cell viability and human health. We are studying, at the cellular level, the mechanisms that maintain and regulate the secretory protein folding environment.

描述（由申请人提供）：我们的目标是阐明内质网（ER）中体内平衡和错误折叠蛋白质应激的物理和分子基础。 ER伴侣对分泌蛋白的正确折叠和质量控制对于细胞和生物的生存能力至关重要。无法正确折叠蛋白质会导致蛋白质功能的丧失，可以激活未折叠的蛋白质反应（UPR）并刺激凋亡死亡。在不同的环境条件下，伴侣是否足够可用于新生或错误折叠的蛋白质，对于理解伴侣功能至关重要。稳态的ER伴侣网络可以用冗余缓冲，并且伴侣过量可以在蛋白质折叠能力的边缘运行。 ER分子伴侣网络的性质对ER感应和应对错误折叠的蛋白质胁迫的含义具有深远的影响。一个以容量运行的系统几乎没有错误的空间，将有明确的压力阈值，并且很可能表现出双相极端。相比之下，压力和稳态可以作为缓冲和冗余系统中的状态梯度存在。可以感知和响应折叠要求中的小扰动，而不会破坏全球折叠环境。我们假设ER伴侣网络的复杂性和缓冲能力调节ER应力途径的激活和ER稳态的维持。伴侣网络的复杂性将取决于Lumenal ER伴侣的分布，动态，组织和占用。尽管遗传学和试管生物化学有助于定义了伴侣的折叠活性，但它仍然不了解ER伴侣伴侣如何实时遇到和与其底物相互作用。我们将采用生化，药理学和定量单细胞荧光显微镜方法来建立具有精美时空分辨率的ER伴侣网络模型。我们的生物物理系统方法将在体内稳态和错误折叠的蛋白质胁迫期间定义ER伴侣网络的层次结构。公共卫生相关性正确的分泌蛋白折叠和质量控制的过程对于细胞活力和人类健康至关重要。我们在细胞水平上研究维持和调节分泌蛋白折叠环境的机制。