Lysine Deacetylases as Coactivators in Glucocorticoid Receptor Signaling

智力优势：细胞通过调节引起基因表达变化的细胞内信号通路来适应环境。直接修饰蛋白质的酶是信号通路的关键组成部分。赖氨酸乙酰化是一种从细菌到人类保守的修饰类型。最近的研究表明，它广泛存在于真核细胞中的蛋白质上，但其在信号传导中的作用知之甚少，调节它的酶，赖氨酸乙酰转移酶（KAT）和赖氨酸脱乙酰酶（KDAC）的作用也是如此。目前对乙酰化、KAT和KDAC功能的理解主要是对组蛋白乙酰化的研究，组蛋白乙酰化有助于基因表达。因此，KAT和KDAC被认为分别促进和损害RNA合成。然而，最近的研究表明，KDAC集中在活性基因的调控区域，它们被促进RNA合成的因子招募到基因中，并且它们的抑制或耗尽可导致基因表达的抑制。此外，许多调节蛋白是乙酰化的，但功能的影响在很大程度上是未知的。在已经研究的少数情况下，乙酰化被发现会损害或增强蛋白质功能。因此，KDAC确实可以促进转录。本项目使用糖皮质激素受体（GR）信号作为模型系统来解决这种可能性。与核受体家族的其他成员一样，GR直接与靶基因结合，并组装促进基因表达的蛋白质复合物。本研究将确定KDAC抑制或耗竭对GR靶基因处GR诱导的复合物组装的影响，鉴定与GR合作激活基因表达的KDAC，评估关键蛋白的乙酰化状态，并确定乙酰化对GR靶基因处蛋白功能的影响。一旦完成，该项目将为乙酰化在GR信号传导中的作用产生新的和非常规的模型，并提供KDAC和非组蛋白乙酰化通过信号传导调节基因表达的贡献的更全面的观点。 更广泛的影响：该研究项目将为研究生，本科生和高中生提供研究和培训机会，以产生基本翻译后修饰的关键新知识。将本科生和高中生纳入研究团队将为研究生提供指导经验，并通过亚利桑那大学的几个项目为代表性不足的群体提供服务，这些项目为这些群体的本科生和高中生提供科学研究和培训机会。所有学生都将接受培训，以发展批判性思维，解决问题和沟通技巧，这将使他们能够追求有助于加强和多样化国家科学劳动力的职业生涯。研究结果将通过在同行评审的开放式期刊上发表、在国家会议上介绍和其他公开演讲机会等方式广泛传播。

Intellectual Merit: Cells adapt to their environment through modulation of intracellular signaling pathways that cause changes in gene expression. Enzymes that modify proteins directly are key components of signaling pathways. Lysine acetylation is a type of modification conserved from bacteria to humans. Recent studies have revealed its widespread occurrence on proteins in eukaryotic cells, but its roles in signaling are poorly understood, and so are the roles of enzymes that regulate it, lysine acetyltransferases (KATs) and lysine deacetylases (KDACs). Present understanding of the functions of acetylation, KATs, and KDACs has been dominated by studies of histone acetylation, which facilitates gene expression. Thus, KATs and KDACs are considered to promote and impair RNA synthesis, respectively. However, recent studies have shown that KDACs are concentrated in regulatory regions of active genes, that they are recruited to genes by factors that promote RNA synthesis, and that their inhibition or depletion can cause repression of gene expression. In addition, many regulatory proteins are acetylated, yet the functional impact is largely uncharacterized. In the few cases that have been studied, acetylation has been found to either impair or enhance protein function. Thus KDACs may indeed facilitate transcription. This project addresses this possibility using glucocorticoid receptor (GR) signaling as a model system. Like other members of the nuclear receptor family, the GR binds directly to target genes and assembles protein complexes that facilitate gene expression. This study will determine the impact of KDAC inhibition or depletion on GR-induced complex assembly at GR target genes, identify the KDACs that cooperate with GR to activate gene expression, assess the acetylation state of key proteins, and define the impact of that acetylation on protein function at GR target genes. Once completed this project will generate new and unconventional models for the role of acetylation in GR signaling and provide a more comprehensive view of the contributions of KDACs and non-histone protein acetylation to regulation of gene expression through signaling. Broader Impacts: The research project will provide research and training opportunities for graduate students, undergraduates, and high school students in the course of generating critical new knowledge of a fundamental post-translational modification. The incorporation of undergraduates and high school students into the research team will provide mentoring experiences to the graduate students and serve under-represented groups through several University of Arizona programs that provide scientific research and training opportunities to undergraduates and high school students from these groups. All students will be trained to develop critical thinking, problem-solving, and communication skills, which will enable them to pursue careers that contribute to strengthening and diversifying the national scientific workforce. The research findings will be broadly disseminated through publication in peer-reviewed, open-access journals and presentations at national meetings and other public-speaking opportunities.