HEAT SHOCK TRANSCRIPTION FACTOR FUNCTION AND REGULATION

由于正常的细胞生长和分裂、感染、暴露于药剂、环境侮辱或处于癌症状态的细胞生长不受控制，所有生物体都不断地暴露在应激条件下。热休克因子(HSF)是一类高度保守的转录因子，能感知和响应多种细胞应激反应，调节对应激状态下的生存和正常细胞内平衡控制至关重要的基因的表达。HSF调节编码蛋白质伴侣的基因的表达，蛋白质伴侣在蛋白质的折叠、成熟、靶向和关键细胞生长控制蛋白的激活中发挥关键作用，以及编码原癌蛋白、疼痛受体、细胞因子和免疫监视分子的基因。在这项应用中，我们描述了以酵母和人类细胞为模型系统的实验，总体目标是了解HSF蛋白质如何感知不同的压力来激活基因表达。首先，酵母细胞通过葡萄糖感应生长控制信号，并传递该信息以激活HSF功能的机制，将通过遗传学、生化和分子生物学方法进行探索。其次，使用酵母细胞和人类细胞，以及体外技术，将研究细胞以非活性形式保留人类HSF蛋白，并对压力信号做出反应以激活HSF分子的机制。第三，不同的人类HSF亚型激活不同的靶基因的分子机制，以及这些基因的鉴定，将在酵母和人类细胞中进行研究。这项提案中描述的实验将提供对这种高度保守的应激反应转录因子类如何感知和响应正常生长期间发生的应激和疾病状态的压力，以维持细胞调节的洞察。

All organisms are constantly exposed to stressful conditions as a consequence of normal cell growth and division, infection, exposure to pharmacological agents, environmental insults or unregulated cell growth in the cancerous state. Heat Shock Factors (HSF) are a class of highly conserved transcription factors which sense and respond to a wide variety of cellular stresses to regulate the expression of genes that are vital to survival during stress and for the establishment of normal cellular homeostatic controls. HSF regulates the expression of genes encoding protein chaperones, which play pivotal roles in protein folding, maturation, targeting and the activation of key cellular growth control proteins, as well as genes encoding proto-oncoproteins, pain receptors, cytokines and immune surveillance molecules. In this application we describe experiments with the overall objective of understanding how HSF proteins sense distinct stresses to activate gene expression, using both yeast and human cells as model systems. First, the mechanisms by which yeast cells sense growth control signals through glucose, and transmit this information to activate HSF function, will be explored through genetic, biochemical and molecular biology approaches. Secondly, using both yeast cells and human cells, as well as in vitro techniques, the mechanisms whereby cells retain human HSF proteins in an inactive form, and respond to stress signals to activate HSF molecules, will be investigated. Third, the molecular mechanisms by which distinct human HSF isoforms activate distinct target genes, and the identification of these genes, will be investigated in both yeast and human cells. The experiments described in this proposal will provide insight into how this highly conserved class of stress- responsive transcription factors sense and respond to stresses that occur during normal growth, and disease states, to maintain cellular regulation.