Structure of Heat Shock Transcription Factor from Yeast

描述（由申请人提供）：热休克转录因子（HSF）是一种转录调节剂，其对热休克和其他胁迫的反应是激活热休克蛋白的表达，热休克蛋白是一组具有关键组成和保护功能的蛋白质。热休克蛋白还在多种疾病状态中发挥多种作用，包括癌症、心血管疾病和涉及蛋白质聚集的神经退行性疾病。在不同条件下控制热休克蛋白表达的能力可能对这些疾病状态有深远的影响。因此，了解HSF的活性是如何被调节的，从而了解如何控制其活性变得非常重要。HSF在应激前具有低水平的活性，应激后获得高水平的转录活性。HSF活性的调节可能涉及其他调节蛋白、翻译后修饰和细胞定位。这一提议的有趣之处在于，HSF内的突变和/或缺失会导致它变得具有组成性活性。因此，HSF结构的完整性似乎是调节其活动的最关键因素。本提案的具体目标集中在dna结合和三聚结构域，这两个结构域的结构和功能是已知的。先前的结构和遗传研究将指导HSF突变体的选择，用于测试电荷、表面拓扑结构、热稳定性和/或整体结构是否对HSF转录活性的正常调节至关重要的假设。此外，还将分析这些突变体对不同热休克启动子的激活能力和受不同胁迫诱导的能力。这些研究将加深我们对HSF结构与其活性的关系的理解，并将有助于实现能够操纵HSF功能以利用其保护作用的长期目标。

DESCRIPTION (provided by applicant): The heat shock transcription factor (HSF) is a transcriptional regulator whose response to heat shock and other stresses is to activate the expression of the heat shock proteins, a set of proteins that have critical constitutive and protective functions. Heat shock proteins also play multiple roles in several disease states, including cancer, cardiovascular problems, and neurodegenerative conditions involving protein aggregation. The ability to control the expression of heat shock proteins under different conditions could have profound effects on these disease states. Therefore, it has become important to understand how the activity of HSF is regulated, so that we can learn how to control its activity. HSF has a low level of activity prior to stress and acquires a high level of transcriptional activity after stress. The modulation of HSF's activity likely involves other regulatory proteins, post-translational modifications, and cellular localization. Of interest to this proposal is the fact that mutations and/or deletions within HSF can cause it to become constitutively active. Therefore, it is the integrity of the HSF structure that appears to be most critical for regulating its activity.The specific aims of this proposal focus on the DNA-binding and trimerization domains, two domains for which much is known about the structure and function. Previous structural and genetic studies will guide the choice of HSF mutants to use to test hypotheses as to whether charge, surface topology, thermal stability, and/or overall structure are critical for the normal regulation of HSF's transcriptional activity. The ability of these mutant HSFs to differentially activate different heat shock promoters and to be differentially induced by different stresses will be also analyzed. These studies will deepen our understanding of how the structure of HSF relates to its activity and will help lead to the long term goal of being able to manipulate HSF's function in order to take advantage of its protective role.