title: Identification of a novel small-molecule agonist for human G protein-coupled receptor 3.
abstract: G protein-coupled receptor 3 (GPR3) is an orphan G protein-coupled receptor (GPCR) predominantly expressed in mammalian brain and oocytes. GPR3 plays important roles in these two organs and is known as a Gαs-coupled receptor-activated constitutively in cells. However, the signal transduction pathway and pharmacological function of GPR3 remain unclear because of the lack of a specific ligand. By use of a human embryonic kidney 293 cell line stably expressing FLAG-GPR3-green fluorescent protein, a chemical screening for GPR3 ligands was performed using homogeneous time-resolved fluorescence cAMP assay. Diphenyleneiodonium chloride (DPI) was identified as a novel agonist of GPR3 with weak or no cross-reactivity with other GPCRs. DPI was further characterized to activate several GPR3-mediated signal transduction pathways, including Ca(2+) mobilization, cAMP accumulation, membrane recruitment of β-arrestin2, and receptor desensitization. Parallel studies revealed that the activity of DPI is much more pronounced than sphingosine 1-phosphate, a previously reported GPR3 agonist. Our study identified a novel and specific agonist of GPR3, which provides a useful tool for further study of this orphan GPCR.
authors.affiliation: Shanghai Key Laboratory of Signaling and Disease Research, Laboratory of Receptor-based Bio-medicine, School of Life Sciences and Technology, Tongji University, Shanghai, China (C.Y., Z.Z., Q.H., R.Z., X.X.); and CAS Key Laboratory of Receptor Research, National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (Z.W., X.X.).
authors.forename: Chenli
authors.initials: C
authors.lastname: Ye
authors.forename: Zhenghong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Zhilong
authors.initials: Z
authors.lastname: Wang
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Hua
authors.forename: Ru
authors.initials: R
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Xie
mesh_terms: D020013:Calcium Signaling / Q000187:drug effects; D018929:Cell Culture Techniques; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism; D057809:HEK293 Cells; D057166:High-Throughput Screening Assays; D006801:Humans; D015394:Molecular Structure; D009861:Onium Compounds / Q000737:chemistry / Q000494:pharmacology*; D043562:Receptors, G-Protein-Coupled / Q000819:agonists* / Q000235:genetics; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology*; D014162:Transfection
chemical_list: C092794:GPR3 protein, human; D009861:Onium Compounds; D043562:Receptors, G-Protein-Coupled; D054852:Small Molecule Libraries; C007517:diphenyleneiodonium; D000242:Cyclic AMP; D019205:GTP-Binding Protein alpha Subunits, Gs