Mechanistic studies of corepressor-mediated PPARγ transcriptional repression

过氧化物酶体增殖物激活受体γ是一种核受体转录因子 通过招募转录辅助调节因子调节细胞分化、脂肪生成和胰岛素抵抗 蛋白质(辅阻遏子和辅活化子)以配体依赖的方式靶向基因启动子。 结构-功能方法已经定义了转录活性的结构构象和 激动剂配体影响PPARγ的共激活剂选择功能。然而，人们对此知之甚少 PPARγ转录抑制构象和辅阻遏子选择功能。我们的长期目标是 通过定义不同的药理PPARγ配体如何影响结构来弥合这一知识差距 以及PPARγ在转录激活和抑制状态之间的功能。在初步研究中，我们解决了 PPARγ配体结合域在转录抑制状态下的晶体结构 独特的辅阻遏子-选择性配体，揭示了我们已经开始验证的独特的结构构象 采用溶液核磁共振方法。在这个项目中，我们将使用力学研究来定义小分子 配体在分子、结构和细胞水平上影响PPARγ的激活和抑制。成功 我们的研究结果将定义PPARγLBD的活性依赖的构象集成， 开发具有增强辅阻遏子选择活性的配体，并通过以下方法确定其分子机制 哪些辅阻遏子选择性抑制配体调节PPARγ细胞功能。

Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor transcription factor that regulates cellular differentiation, adipogenesis, and insulin resistance by recruiting transcriptional coregulator proteins (corepressor and coactivator proteins) to target gene promoters in a ligand-dependent manner. Structure-function approaches have defined how the transcriptionally active structural conformation and coactivator-selective functions of PPARγ are influenced by agonist ligands. However, little is known about the transcriptionally repressive conformation and corepressor-selective functions of PPARγ. Our long-term goal is to close this knowledge gap by defining how different pharmacological PPARγ ligands influence the structure and function of PPARγ between transcriptionally active and repressive states. In preliminary studies, we solved crystal structures of the PPARγ ligand-binding domain (LBD) in a transcriptionally repressive state using a unique corepressor-selective ligand, revealing a unique structural conformation that we have started to validate using solution NMR methods. In this project, we will use mechanistic studies to define how small molecule ligands impact PPARγ activation and repression on the molecular, structural, and cellular levels. Successful outcomes from our studies will define the activity-dependent conformational ensemble of the PPARγ LBD, develop ligands with enhanced corepressor-selective activity, and determine the molecular mechanisms by which corepressor-selective repressive ligands modulate PPARγ cellular functions.