title: Expression of orphan G-protein coupled receptor GPR174 in CHO cells induced morphological changes and proliferation delay via increasing intracellular cAMP.
abstract: We established cell lines that stably express orphan GPCR GPR174 using CHO cells, and studied physiological and pharmacological features of the receptor. GPR174-expressing cells showed cell-cell adhesion with localization of actin filaments to cell membrane, and revealed significant delay of cell proliferation. Since the morphological changes of GPR174-cells were very similar to mock CHO cells treated with cholera toxin, we measured the concentration of intracellular cAMP. The results showed the concentration was significantly elevated in GPR174-cells. By measuring intracellular cAMP concentration in GPR174-cells, we screened lipids and nucleotides to identify ligands for GPR174. We found that lysophosphatidylserine (LysoPS) stimulated increase in intracellular cAMP in a dose-dependent manner. Moreover, phosphorylation of Erk was elevated by LysoPS in GPR174 cells. These LysoPS responses were inhibited by NF449, an inhibitor of Gα(s) protein. These results suggested that GPR174 was a putative LysoPS receptor conjugating with Gα(s), and its expression induced morphological changes in CHO cells by constitutively activating adenylyl cycles accompanied with cell conjunctions and delay of proliferation.
authors.affiliation: Laboratory of Pharmacoinformatics, Graduate School of Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Sugita
authors.forename: Chiaki
authors.initials: C
authors.lastname: Yamamura
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Tabata
authors.forename: Norihisa
authors.initials: N
authors.lastname: Fujita
mesh_terms: D000818:Animals; D016466:CHO Cells; D002448:Cell Adhesion; D049109:Cell Proliferation; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D008246:Lysophospholipids / Q000494:pharmacology; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*
chemical_list: C581018:GPR174 protein, human; D008024:Ligands; D008246:Lysophospholipids; D043562:Receptors, G-Protein-Coupled; C025059:lysophosphatidylserine; D000242:Cyclic AMP; D020929:Mitogen-Activated Protein Kinase Kinases