Mechanistic studies of corepressor-mediated PPARγ transcriptional repression

过氧化物酶体增殖物激活受体γ（过氧化物酶体增殖物激活受体γ）是一种核受体转录因子， 通过募集转录辅助调节因子调节细胞分化、脂肪形成和胰岛素抵抗 蛋白（辅阻遏蛋白和辅激活蛋白）以配体依赖性方式靶向基因启动子。 结构-功能方法已经定义了转录活性结构构象和 PPARγ的辅激活剂选择性功能受激动剂配体的影响。然而，人们对此知之甚少。 转录抑制构象和辅抑制因子选择性功能。我们的长期目标是 通过定义不同的药理学PPARγ配体如何影响结构， 以及PPARγ在转录活性和抑制状态之间的功能。在初步研究中，我们解决了 使用晶体结构的过氧化物酶体增殖物激活受体γ配体结合域（LBD）在转录抑制状态下， 独特的辅阻遏物选择性配体，揭示了我们已经开始验证的独特结构构象 使用溶液NMR方法。在这个项目中，我们将使用机械研究来定义小分子如何 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PPARγ LBD的活性依赖性构象集合， 开发具有增强的辅阻遏物选择性活性的配体，并通过以下方式确定分子机制： 其辅阻遏物选择性阻遏配体调节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.