Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR 999077, China.
Laboratory for Synthetic Chemistry and Chemical Biology Limited, Health@InnoHK, Innovation and Technology Commission, Units 1503-1511, 15/F., Building 17W, Hong Kong SAR 999077, China.
J Am Chem Soc. 2024 Sep 4;146(35):24638-24653. doi: 10.1021/jacs.4c08624. Epub 2024 Aug 22.
Identifying biologically active ligands for membrane proteins is an important task in chemical biology. We report an approach to directly identify small molecule agonists against membrane proteins by selecting DNA-encoded libraries (DELs) on live cells. This method connects extracellular ligand binding with intracellular biochemical transformation, thereby biasing the selection toward agonist identification. We have demonstrated the methodology with three membrane proteins: epidermal growth factor receptor (EGFR), thrombopoietin receptor (TPOR), and insulin receptor (INSR). A ∼30 million and a 1.033 billion-compound DEL were selected against these targets, and novel agonists with subnanomolar affinity and low micromolar cellular activities have been discovered. The INSR agonists activated the receptor by possibly binding to an allosteric site, exhibited clear synergistic effects with insulin, and activated the downstream signaling pathways. Notably, the agonists did not activate the insulin-like growth factor 1 receptor (IGF-1R), a highly homologous receptor whose activation may lead to tumor progression. Collectively, this work has developed an approach toward "functional" DEL selections on the cell surface and may provide a widely applicable method for agonist discovery for membrane proteins.
鉴定膜蛋白的生物活性配体是化学生物学中的一项重要任务。我们报告了一种通过在活细胞上选择 DNA 编码文库（DEL）直接鉴定针对膜蛋白的小分子激动剂的方法。该方法将细胞外配体结合与细胞内生化转化联系起来，从而偏向于激动剂的鉴定。我们已经用三种膜蛋白：表皮生长因子受体（EGFR）、血小板生成素受体（TPOR）和胰岛素受体（INSR）证明了该方法的可行性。针对这些靶标，我们选择了约 3000 万个和 10.33 亿个化合物 DEL，并发现了具有亚纳摩尔亲和力和低微摩尔细胞活性的新型激动剂。INSR 激动剂可能通过结合变构位点激活受体，与胰岛素表现出明显的协同作用，并激活下游信号通路。值得注意的是，这些激动剂不会激活胰岛素样生长因子 1 受体（IGF-1R），这是一种高度同源的受体，其激活可能导致肿瘤进展。总的来说，这项工作开发了一种在细胞表面进行“功能”DEL 选择的方法，可能为膜蛋白激动剂的发现提供一种广泛适用的方法。
