Full-length LRH-1 structural regulation

LRH-1(NR5A2)是一种单体核受体，参与肝脏生理的多个方面，包括胆汁酸、胆固醇和葡萄糖的动态平衡。在临床前期的小鼠模型中，LRH-1的激活对肝脏代谢有有利的影响。由于像LRH-1这样的核受体有一个非常可药物的配体结合口袋，LRH-1已经成为许多药物开发的靶点，最近取得了很大的进展，但临床上仍然没有LRH-1激动剂。与大多数其他核受体一样，LRH-1由DNA结合域和配体结合域组成，这两个结构域由一个大的非结构铰链结构域连接。经典的核受体药物设计主要集中在分离的配体结合结构域上，因为这个分离结构域的调节机制在分子水平上被很好地理解：疏水性小分子的结合变构改变转录辅助调节因子的配体结合结构域招募，从而调节核受体的功能。然而，一些证据表明，LRH-1结构域之间存在域间通信，调节功能。了解这种跨领域交流背后的结构生物学可能有助于LRH-1药物设计工作，然而，尽管几个小组做出了巨大努力，但应用结晶学或低温EM的技术挑战阻碍了进展。我们使用集成的结构方法开发了完整的全长LRH-1的低分辨率但高置信度的模型，仅使用基于溶液的生物物理分析和计算模型(HDX、SAXS、化学交联剂、人工氨基酸二苯甲酮交联剂、Cys-Cys域间交联剂、Rosetta和MD模拟)。该模型解释了人类患者突变和预测驻留在结构域之间的基于结构的突变，我们显示了改变全长LRH-1的结构和功能。在这里，我们建议利用这种基于解决方案的方法来解决该领域中的几个长期存在的问题：目标1确定各种配体如何改变全长LRH-1域间通信。目标2解决了相扑模块翻译后修改如何改变LRH-1域间通信。目的3鉴定LRH-1结构型突变对小鼠肝脏和原代肝细胞的影响。我们目前对LRH-1结构如何调控的理解仅限于对单个结构域的研究。如果不了解全长LRH-1是如何被调控的，我们就不能知道我们目前的药物设计努力是否充分利用了LRH-1的整个治疗能力。

LRH-1 (NR5A2) is a monomeric nuclear receptor involved in many aspects of liver physiology, including bile acid, cholesterol and glucose homeostasis. LRH-1 activation has beneficial effects on liver metabolism in pre-clinical mouse models. As nuclear receptors like LRH-1 have a very druggable ligand-binding pocket, LRH-1 has been targeted by many drug development efforts with great recent progress, however an LRH-1 agonist is still not available in the clinic. Like most other nuclear receptors, LRH-1 is composed of a DNA-binding domain and a ligand-binding domain, which are connected by a large unstructured Hinge domain. Classic nuclear receptor drug design has focused on the isolated ligand-binding domain, as the regulatory mechanism of this isolated domain is very well understood at the molecular level: binding of a hydrophobic small molecule allosterically alters ligand-binding domain recruitment of a transcriptional coregulator, which regulates nuclear receptor function. However, several lines of evidence suggest inter-domain communication exists between LRH-1 domains, regulating function. Understanding the structural biology behind this inter-domain communication might help LRH-1 drug design efforts, however technical challenges in applying crystallography or cryo-EM has prevented progress, despite great effort from several groups. We used an integrated structural approach to develop a low-resolution, but high confidence model of the intact, full-length LRH-1, using exclusively solution-based biophysical analyses and computational modeling (HDX, SAXS, chemical crosslinking, artificial amino acid benzophenone cross linking, Cys-Cys interdomain crosslinking, Rosetta and MD simulations). The model explains human patient mutations and structure-based mutations predicted to reside in the interface between the domains, which we show alter full length LRH-1 structure and function. Here, we propose to take advantage of this solution-based approach to address several long-standing questions in the field: Aim 1 determines how various ligands change full length LRH-1 interdomain communication. Aim 2 resolves how the SUMO module post-translational modification alters LRH-1 interdomain communication. Aim 3 identifies the genes effected by structure-based LRH-1 mutations in mouse liver and primary hepatocytes. Our current understanding of how LRH-1 structure is regulated is limited to studies of the individual domains. Without understanding how full-length LRH-1 is regulated, we cannot know if our current drug design efforts are taking full advantage of the entire therapeutic capacity of LRH-1.