Regulation of Heat Shock Factor 1 in Animal Models

描述（由申请人提供）：应激反应是一种进化保守的细胞反应机制，其特征是热休克蛋白（Hsps）的合成和积累增强。热休克蛋白与控制细胞生长和发育的信号通路的关键成分有关。热休克蛋白的水平是至关重要的，因为热休克蛋白表达水平的变化会导致异常生长、发育缺陷和细胞死亡。热休克蛋白编码基因的应激诱导表达受热休克转录因子（Hsfs）家族的调控。Hsf1是主要的应激反应家族成员，在其激活和失活的周期中经历复杂的修饰，如磷酸化和与许多调节蛋白的关联。进化保守丝氨酸残基S303和S307的磷酸化以及与Hsf结合蛋白1 （Hsbp1）的关联抑制Hsf1的活性。通过在小鼠中破坏Hsf1基因，已经测试了在脊椎动物中具有进化保守的Hsf1的意义。对突变小鼠的研究表明，hsf1在维持细胞基本功能和抗凋亡蛋白中起关键作用。为了继续了解磷酸化对Hsf1活性和功能的作用，并确定Hsf1相互作用蛋白Hsbp1在调节Hsf1活性中的作用，我们建立了一个突变小鼠模型，其中丝氨酸残基S303/S307被丙氨酸残基（S303A/S307A）所取代，我们在小鼠中破坏了Hsbp1基因。这些小鼠模型，除了我们已经产生的Hsf1缺陷小鼠外，将用于了解Hsf1水平和活性的操纵如何控制细胞生长或应激反应。我们提出以下具体目标：1 .确定参与Hsf1调控的信号网络以及磷酸化对Hsf1活性的影响；确定Hsbp1在体内调控Hsf1转录活性中的作用；探讨Hsf1在应激反应和细胞凋亡调控中的生理作用。

DESCRIPTION (provided by applicant): The stress response is an evolutionary conserved cellular response mechanism characterized by the enhanced synthesis and accumulation of heat shock proteins (Hsps). Hsps associate with key components of the signaling pathways that control cell growth and development. The level of Hsps is critical since variations in the level of Hsps' expression result in aberrant growth, developmental defects and cell death. The stress-inducible expression of Hsps' encoding genes is regulated by a family of heat shock transcription factors (Hsfs). Hsf1 is the major stress-responsive family member and during its cycle of activation and inactivation undergoes complex modifications such as phosphorylation and association with number of regulatory proteins. Phosphorylation of evolutionary conserved serine residues S303 and S307 and association with Hsf binding protein 1 (Hsbp1), repress Hsf1 activity. The significance of having an evolutionary conserved Hsf1 in vertebrates has been tested through the disruption of the hsf1 gene in the mouse. Studies of the mutant mouse reveal that hsf1 plays a critical role in maintenance of essential cellular functions and as an anti-apoptotic protein. In this grant application, to continue our efforts to understand the role of phosphorylation on Hsf1 activity and function, and to determine the roles of Hsbp1, which is an Hsf1 interacting protein, in regulating Hsf1 activity, we have generated a mutant mouse model where the serine residues S303/S307 have been replaced by alanine residues (S303A/S307A), and we have disrupted the hsbp1 gene in mice. These mouse models, in addition to hsf1-deficient mice we already have generated, will be used to understand how manipulation of Hsf1 levels and activity controls cellular growth or stress response. We propose the following specific aims: I. To identify the signaling networks involved in Hsf1 regulation and the consequence of phosphorylation on Hsf1 activity, II. To determine the function of Hsbp1 in controlling Hsf1 transcriptional activity in vivo, and III. To characterize the physiological role of Hsf1 in regulation of the stress response and apoptosis.