Biophysical Studies on Nuclear Receptor LBDs

本项目的目标是确定药物调节的作用机制， 转录因子，在原子水平上称为核受体（NR）。激素 糖皮质激素、类维生素A、甲状腺激素和维生素衍生的激素等分子 它们通过调节细胞内的靶基因的转录来发挥作用。 细胞核这些激素通过直接结合和调节 NR的活动。这些蛋白质几乎指导着人类免疫系统的各个方面， 生理学和不适当的功能可以导致几种疾病状态 乳腺癌、糖尿病、肥胖症、心脏病、骨质疏松症， 与衰老有关。NR通常作为异源二聚体起作用，例如甲状腺受体： 类维生素A X受体（TR：RXR）和组成型雄烷受体（CAR：RXR） TR，CAR和RXR可以各自识别特定的激素信号的复合物。 尽管关于NR的遗传学和细胞定位的数据丰富， 相对较少了解这些调节的精确分子机制， proteins.这些受体的配体结合域（LBD）是变构的中心 这是NR反式激活所必需的。利用生物物理学工具和细胞- 基于转录测定，该项目将确定如何结合和 远端位点的点突变可影响共调节蛋白的募集， 两个酶结合位点如何相互联系以调节转录活性 异源二聚体TR：RXR和CAR：RXR。将通过X射线确定结构 晶体学指导构象运动的生物物理分析， 转录活性这些研究的一个重要结果是， NRs的动力学是开发更有效疗法的潜力。

The goal of this project is to determine the mechanism of action of hormone-regulated transcription factors, called nuclear receptors (NR) at the atomic level. Hormonal molecules such as glucocorticoids, retinoids, thyroid and vitamin-derived hormones exert their effects by regulating the transcription of hormone-responsive target genes within the nucleus of cells. These hormones function by directly binding to and modulating the activity of NRs. These hormone-regulated proteins direct almost every aspect of human physiology and improper function can lead to several disease states such as prostate and breast cancer, diabetes, obesity, heart disease, osteoporosis, and processes associated with aging. NRs often function as heterodimers such as the thyroid receptor: retinoid X receptor (TR:RXR) and the constitutive androstane receptor (CAR:RXR) complexes where TR, CAR and RXR can each recognize specific hormonal signals. Despite the wealth of data on the genetics and cellular localization of NRs, there is relatively little known of the precise molecular mechanisms of regulation of these proteins. The ligand binding domain (LBD) of these receptors is central to the allostery that is essential for NR transactivation. Using a combination of biophysical tools and cell- based transcription assays this project will determine the how hormone-binding and point mutations at distant sites can affect the recruitment of co-regulatory proteins and how the two hormone-binding sites communicate to regulate the transcriptional activity of heterodimeric TR:RXR and CAR:RXR. Structures will be determined by X-ray crystallography to guide biophysical analyses of conformational movements and transcriptional activity. An important consequence of these studies on the structure and dynamics of NRs is the potential for developing more effective therapies.