Regulation of HSF1 and HSF2 by SUMO-1 Modification

描述（由申请人提供）： 本申请的长期目标是阐明调节热休克蛋白（hsps）的应激诱导的和组成型表达的机制，所述热休克蛋白不仅对于细胞暴露于应激条件下的存活能力而且对于非应激细胞中的正常蛋白质折叠都是关键的。转录调节蛋白HSF 1和HSF 2的应激诱导型与组成型活性对于这种应激激活和基础HSP基因表达是至关重要的，但它们的差异调节活性是如何控制的尚不清楚。在寻找这一机制，我们已经确定了差异调节SUMO-1修饰的HSF 1和HSF 2导致应力诱导和组成性激活，分别。我们建议，SUMO-1修饰的HSFs是先决条件，他们的转录活性的水平，他们的能力，与热休克蛋白基因的启动子（DNA结合活性），组装的转录复合物与其他因素对这些启动子（反式激活潜力），并为他们提供保护，防止退化。在本申请中，我们将1）确定SUMO-1修饰对HSF 1和HSF 2的DNA结合和反式激活活性的功能后果，2）表征该修饰在调节HSF 1和HSF 2的周转中的作用，和3）鉴定介导HSF 1和HSF 2的应激诱导的与组成性SUMO-1修饰的差异调节的机制，确定HSF类小泛素化对体内蛋白质错误折叠的意义，并确定HSF类小泛素化是否因细胞老化而改变。从拟议的研究结果将定义的基础上的差异调节的HSF 1和HSF 2导致应激诱导和组成型表达的热休克蛋白，并可能提供一种策略，用于操纵细胞热休克蛋白的表达，一个有前途的潜在治疗引起的疾病蛋白质错误折叠/聚集，如帕金森氏症，亨廷顿氏症，和阿尔茨海默氏症。

DESCRIPTION (provided by applicant): The long-term goal of this application is to elucidate the mechanism(s) that regulate stress-induced and constitutive expression of heat shock proteins (hsps), which are critical not only for the cell's ability to survive exposure to stress conditions but also for normal protein folding in non-stressed cells. The stress-inducible vs. constitutive activities of the transcriptional regulatory proteins HSF1 and HSF2 are critical for this stress-activated and basal hsp gene expression, but how their differentially-regulated activities are controlled is unknown. In the search for this mechanism, we have identified differential regulation of SUMO-1 modification of HSF 1 and HSF2 leading to stress-induced and constitutive activation, respectively. We propose that SUMO-1 modification of HSFs is pre-requisite for their transcriptional activities at the levels of their ability to interact with promoters of hsp genes (DNA-binding activities), for assembly of transcription complexes with other factors on these promoters (transactivation potential), and for their protection against degradation. In this application we will 1) determine the functional consequences of SUMO-1 modification for the DNA-binding and transactivation activities of HSF 1 and HSF2, 2) characterize the role of this modification in regulating the turnover of HSF1 and HSF2, and 3) identify the mechanism(s) which mediate the differential regulation of stress-induced vs. constitutive SUMO-1 modification of HSF1 and HSF2, determine the significance of HSF sumoylation for protein misfolding in vivo, and determine whether sumoylation of HSFs is altered by cellular aging. Results from the proposed studies will define the basis of the differential regulation of HSF 1 and HSF2 leading to stress-induced and constitutive expression of heat shock proteins, and may provide a strategy for manipulating cellular heat shock protein expression, a promising potential treatment of diseases caused by protein misfolding/aggregation such as Parkinson's, Huntington's, and Alzheimer's Disease.