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)内稳态和错误折叠的蛋白质应激的物理和分子基础。内质网伴侣对分泌蛋白的正确折叠和质量控制对细胞和生物体的生存至关重要。蛋白质不能正确折叠会导致蛋白质功能丧失，激活未折叠蛋白反应(UPR)，刺激细胞凋亡。在不同的环境条件下，伴侣对新生或错误折叠的蛋白质是否具有足够的可利用性，对于了解伴侣的功能至关重要。稳定状态下的内质网分子伴侣网络可以通过冗余和过量的分子伴侣来缓冲，也可以使网络运行在蛋白质折叠能力的边缘。内质网伴侣网络的性质对内质网如何感知和应对错误折叠的蛋白质应激具有深远的影响。一个以最大容量运行的系统几乎没有错误的空间，将有一个明确的压力阈值，并且很可能出现两相极端。相比之下，压力和动态平衡可以作为缓冲和冗余系统中的状态梯度而存在。折叠要求中的微小扰动可以被感知和响应，而不会扰乱全球折叠环境。我们假设，内质网伴侣网络的复杂性和缓冲能力调节了内质网应激通路的激活和内质网稳态的维持。伴侣网络的复杂性将取决于管腔内质网伴侣的分布、动态、组织和占有率。虽然遗传学和试管生物化学已经帮助确定了伴侣的折叠活性，但对内质网伴侣如何在细胞内实时遇到并与底物相互作用仍知之甚少。我们将使用生化、药理学和定量单细胞荧光显微镜方法建立具有精细时空分辨率的内质网伴侣网络模型。我们的生物物理系统方法将定义内质网伴侣网络在动态平衡和错误折叠蛋白质应激期间的层次结构。与公共健康相关正确的分泌蛋白质折叠过程和质量控制对细胞存活和人类健康至关重要。我们正在细胞水平上研究维持和调节分泌性蛋白质折叠环境的机制。