Quantitative approaches to reveal the homeostatic control mechanisms of stress re

描述(申请人提供)：面对无数外界的侮辱，如温度变化和渗透压失衡，细胞必须调整其生化活动，以满足不断变化的需求。为了对抗环境挑战或压力，细胞进化了一系列应激反应通路，当细胞失去平衡时，这些通路作为纠正反馈环来恢复体内平衡。应激反应是古老的，核心通路在所有真核生物中都是保守的。这些途径的缺陷--无法恢复体内平衡--可能会产生有害的影响，比如在糖尿病等疾病状态下。此外，病原体和癌症可以选择性地调节和利用应激反应途径来利用它们的细胞保护功能。虽然几十年的遗传学、生物化学和表达谱分析已经确定了这些途径，解决了基本的激活机制，并揭示了目标基因，但我们目前对应激反应途径的了解既缺乏深度也缺乏广度。它缺乏深度，因为我们不知道实时控制这些通路的机制，以确保在应激时足够的激活和一旦内稳态恢复后有效的去激活。我们的理解缺乏广度，因为这些通路一般都是独立研究的，忽略了潜在的相互联系。定量和机械地了解这些通路是如何调节以恢复内稳态的，以及了解不同的应激反应如何作为一个相互连接的网络运行是有效调节这些通路以达到治疗目的的先决条件。在此背景下，我提出了三个具体目标，以增加我们对控制应激反应途径的数量调控机制的理解的深度，以及我们对这些反应之间相互联系的理解的广度。在前两个目标中，我将重点放在热休克反应，基本和典型的应激反应，以揭示磷酸化和伴侣蛋白结合动力学如何定量调节转录因子HSF1的活性。在第三个目标中，我将通过建立一个压力报告菌株小组来关注应激反应途径之间的相互联系，该小组将允许同时测量任何遗传或环境扰动后的所有应激反应。这项拟议的研究具有重要意义，因为它将为我们理解应激反应提供深度和广度。这样的理解是有效利用这些重要途径获得治疗益处的先决条件。最后，我期望这里描述的机械系统生物学方法将作为对日益复杂的系统中的路径和网络进行定量研究的模型。

DESCRIPTION (provided by applicant): Faced with myriad external insults, like temperature changes and osmolarity imbalances, cells must adjust their biochemical activities to meet ever-shifting demands. To counteract environmental challenges, or stresses, cells have evolved a collection of stress response pathways that work as corrective feedback loops to restore homeostasis when the cell is thrown out of equilibrium. Stress responses are ancient and the core pathways are conserved in all eukaryotes. Defects in these pathways - failures to restore homeostasis - can have deleterious effects, as in disease states like diabetes. Moreover, pathogens and cancers can selectively modulate and exploit stress response pathways to harness their cytoprotective functions. While decades of genetics, biochemistry and expression profiling have identified the pathways, worked out the basic activation mechanisms and revealed the target genes our current understanding of stress response pathways lacks both depth and breadth. It lacks depth in that we do not know the mechanisms that control the pathways in real-time to ensure sufficient activation upon stress and efficient deactivation once homeostasis is restored. Our understanding lacks breadth in that the pathways have generally been studied independently, neglecting potential interconnections. A quantitative and mechanistic understanding of how these pathways are regulated to restore homeostasis and knowledge of how the different stress responses operate as an interconnected network are prerequisites to effectively modulating these pathways for therapeutic purposes. In this context, I propose three specific aims to increase the depth of our understanding of the quantitative regulatory mechanisms that control stress response pathways and the breadth of our understanding of the interconnections between these responses. In the first two aims I will focus on the heat shock response, the elemental and and prototypical stress response, to reveal how phosphorylation and chaperone protein binding dynamics quantitatively regulate the activity of the transcription factor, Hsf1. In the third aim, I will focus on the interconnections between stres response pathways by building a panel of stress reporter strains that will allow simultaneous measurement of all stress responses following any genetic or environmental perturbation. The proposed research is significant because it will provide depth and breadth to our understanding of stress responses. Such understanding is a prerequisite to effectively harnessing these vital pathways for therapeutic benefit. Finally, I expect that the mechanistic systems biology approach described here will serve as a model for the quantitative investigation of pathways and networks in increasingly complex systems.