蛋白质多肽激素是一类重要的内源信号分子，通过激活靶细胞膜上特定受体发挥功能，已知能激活100多个G蛋白偶联受体（GPCRs），是一类重要的GPCR内源配基。近年发现了一些新的蛋白质多肽激素，找到它们的受体成为一项重要任务。目前还有100多个孤儿GPCRs，我们推测其中相当一部分可能是蛋白质多肽激素的受体。在本项目中，我们拟从本实验室最近构建的95个人源孤儿GPCRs中筛选蛋白质多肽激素的受体。首先通过大肠杆菌重组表达及化学肽合成获得40种以上受体未知的人源蛋白质多肽激素并用荧光探针标记。随后通过配基诱导受体内吞可视化观察和G蛋白信号通路报告基因测活两种筛选方法，逐一测试过表达在HEK293T细胞中的孤儿GPCRs，找出可被激活的受体并进一步确认。该筛选策略有望在蛋白质多肽激素和孤儿GPCRs间架起一座有效沟通的桥梁，预期找到1-2个蛋白质多肽激素的受体，为深入功能研究及药物开发打下基础。

Protein/peptide hormones are an important group of endogenous signal molecules that exert various biological functions by activating specific membrane receptors of the target cells. It is known that protein/peptide hormones can activate more than 100 G protein-coupled receptors (GPCRs), being an important group of the endogenous GPCR ligands. In recent years, some novel protein/peptide hormones have been discovered, thus identification of their receptors becomes an important task. So far, there are over 100 orphan human GPCRs, we deduced that a substantial portion of these orphan GPCRs are probably the receptors of protein/peptide hormones. In the present project, we plan to screen receptors of some protein/peptide hormones from 95 orphan human GPCRs recently generated in our laboratory. First, preparing over 40 human protein/peptide hormones with unknown receptors through recombinant expression in E. coli or chemical peptide synthesis and labeling them by fluorescent probe. Second, screening the orphan human GPCRs overexpressed in HEK293T cells one by one through visualization of the ligand-induced receptor internalization and reporter assay of the G protein signaling pathways, identifying the activated receptors and confirming the novel ligand-receptor pairs. The present screening approach would establish a tight connection between protein/peptide hormones and orphan GPCRs and hopefully identify 1-2 novel ligand-receptor pairs, thus paving the way for further functional studies and drug development.