Identification of Allsoteric Ligands for Hepatic Nuclear Factor 4-alpha

描述（由申请人提供）：肝细胞核因子4-α（HNF 4）是转录因子核受体家族的成员。HNF 4控制肝脏和胰腺中与胰岛素和葡萄糖产生相关的基因。HNF 4的突变导致年轻人1型糖尿病（MODY 1）的成熟发作和人类高胰岛素血症性低血糖（HH）。核受体超家族的成员在其配体结合结构域（LBD）内具有疏水口袋。传统的药物筛选策略利用这些口袋，由孤立的LBD的已知结构指导。该领域缺乏全长受体的高分辨率结构，因此没有考虑这些蛋白质中其他可药用位点的可能性。我们已经获得了一个完整的晶体结构HNF 4同源二聚体，在功能上揭示其DNA响应元件的复合物。这种结构出乎意料地揭示了结构域-结构域连接处的两个位点，小分子可以结合在那里。我们的突变研究和先前的翻译后修饰知识表明，这些位点可以变构调节HNF 4的DNA亲和力。我们提出了一个高通量的筛选活动，连同验证性试验和机制研究，利用这些新的网站在HNF 4。我们的目标是确定DNA结合的增效剂，有利于某些MODY 1和HH疾病人群，其中受体-DNA结合受到HNF 4点突变的影响。

DESCRIPTION (provided by applicant): The hepatocyte nuclear factor 4-alpha (HNF4) is a member of the nuclear receptor family of transcription factors. HNF4 controls genes in the liver and pancreas related to insulin and glucose production. Mutations in HNF4 cause Maturity Onset of Diabetes in Young 1 (MODY1), and hyperinsulinemic hypoglycemia (HH) in humans. Members of the nuclear receptor superfamily have a hydrophobic pocket inside their ligand binding domains (LBDs). Traditional drug screening strategies exploit these pockets, guided by known structures of isolated LBDs. The field has lacked high-resolution structures for full-length receptors, and therefore not considered the possibility of other druggable sites elsewhere in these proteins. We have obtained a complete crystal structure HNF4 homodimer, in a functionally revealing complex with its DNA response element. This structure unexpectedly reveals two sites at domain-domain junctions, where small molecules could bind. Our mutational studies, and previous knowledge of post-translational modifications, show these sites can allosterically regulate the DNA affinity of HNF4 . We propose a high-throughput screening campaign, together with confirmatory assays and mechanistic studies that exploit these new sites in HNF4 . Our goal is to identify potentiators of DNA binding that benefit certain MODY1 and HH disease populations where receptor-DNA binding is compromised by point mutations in HNF4 .