title: Nuclear localization of Formyl-Peptide Receptor 2 in human cancer cells.
abstract: Current models of G protein-coupled receptors (GPCRs) signaling describe binding of external agonists to cell surface receptors which, in turn, trigger several biological responses. New paradigms indicate that GPCRs localize to and signal at the nucleus, thus regulating distinct signaling cascades. The formyl-peptide receptor FPR2 belongs to the GPCR super-family and is coupled to PTX-sensitive Gi proteins. We show by western blot analysis, immunofluorescence experiments and radioligand binding assays that FPR2 is expressed at nuclear level in CaLu-6 and AGS cells. Nuclear FPR2 is a functional receptor, since it participates in intra-nuclear signaling, as assessed by decreased G protein-FPR2 association and enhanced ERK2, c-Jun and c-Myc phosphorylation upon stimulation of intact nuclei with the FPR2 agonist, WKYMVm. We analyzed FPR2 sequence for the search of a nuclear localization sequence (NLS) and we found a stretch of basic aminoacids (227-KIHKK-231) in the third cytoplasmic loop of the receptor. We performed single (K230A) and multiple (H229A/K230A/K231A) mutagenesis of NLS. The constructs were individually overexpressed in HEK293 cells and immunofluorescence and western blot analysis showed that nuclear localization or translocation of FPR2 depends on the integrity of the H(229) and K(231) residues within the NLS.
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Cattaneo
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy.
authors.forename: Melania
authors.initials: M
authors.lastname: Parisi
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; IRCCS SDN, Via E. Gianturco 113, Naples 80143, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Fioretti
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; CEINGE-Biotecnologie Avanzate s.c.a.r.l., Via G. Salvatore 486, Naples 80145, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Sarnataro
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; CEINGE-Biotecnologie Avanzate s.c.a.r.l., Via G. Salvatore 486, Naples 80145, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Esposito
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy. Electronic address: rosario.ammendola@unina.it.
authors.forename: Rosario
authors.initials: R
authors.lastname: Ammendola
mesh_terms: D021581:Active Transport, Cell Nucleus; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000201:enzymology*; D057809:HEK293 Cells; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008856:Microscopy, Fluorescence; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D016296:Mutagenesis; D009369:Neoplasms / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D044042:Receptors, Formyl Peptide / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D044067:Receptors, Lipoxin / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: C105101:FPR2 protein, human; D016271:Proto-Oncogene Proteins c-myc; D044042:Receptors, Formyl Peptide; D043562:Receptors, G-Protein-Coupled; D044067:Receptors, Lipoxin; D048031:JNK Mitogen-Activated Protein Kinases; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1
keywords: FPR2; G protein-coupled receptors; Nuclear localization; Signal transduction