title: Delta opioid receptors expressed by stably transfected jurkat cells signal through the map kinase pathway in a ras-independent manner.
abstract: Delta opioid receptors (DOR) are G-protein coupled 7-transmembrane receptors (GPCR), expressed by thymic and splenic T cells, that modulate interleukin (IL)-2 production and proliferation in response to concanavalin A or crosslinking the TCR. Mitogen-activated protein kinases (MAPKs) are involved in mediating intracellular responses to TCR crosslinking. In addition, MAPKs can be activated by signaling cascades that are initiated by the release of G-proteins from GPCRs. To determine whether DORs expressed by T cells signal through the MAPKs, extracellular-regulated kinases (ERKs) 1 and 2, two delta opioid peptides, deltorphin and [D-Ala2,D-Leu5]-enkephalin (DADLE), were studied in Jurkat cells that had been stably transfected with DOR (DOR-Ju.1). These peptides rapidly and dose-dependently induced ERK phosphorylation; pretreatment with naltrindole (NTI), a selective DOR antagonist, abolished this. Pertussis toxin (PTX) also inhibited phosphorylation, indicating the involvement of the Gi/o proteins. Herbimycin A, a protein tyrosine kinase (PTK) inhibitor, reduced the DADLE-induced ERK phosphorylation by 68%. ERK phosphorylation was inhibited by Bisindolylmaleimide 1 (GF109203X), an inhibitor of PKC, and by pretreatment with PMA prior to DADLE. A GTP/GDP exchange assay was used to assess the potential role of Ras in the pathway leading to ERK phosphorylation; DADLE failed to stimulate GTP/GDP exchange in comparison to PMA. Additional studies showed that DADLE stimulated an increase in cfos mRNA; this was reduced by the inhibitor of MAPK/ERK kinase (MEK), PD98059. Therefore, in DOR-Ju.1 cells, DOR agonists stimulate ERK phosphorylation in a Ras independent and PKC-dependent manner; PTKs appear to be involved. MAPKs mediate the increase in cfos mRNA induced by DOR agonists.
authors.affiliation: Endocrine-Neuroscience and Neuroimmunomodulation Research Laboratories, Minneapolis Medical Research Foundation, Hennepin County Medical Center and University of Minnesota, 55404, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Shahabi
authors.forename: Y
authors.initials: Y
authors.lastname: Daaka
authors.forename: K
authors.initials: K
authors.lastname: McAllen
authors.forename: B M
authors.initials: BM
authors.lastname: Sharp
mesh_terms: D000276:Adjuvants, Immunologic / Q000378:metabolism; D000818:Animals; D016227:Benzoquinones; D020013:Calcium Signaling / Q000187:drug effects / Q000276:immunology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002273:Carcinogens / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine / Q000494:pharmacology; D004789:Enzyme Activation / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D020690:GTPase-Activating Proteins; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000276:immunology; D006801:Humans; D019169:Jurkat Cells / Q000737:chemistry* / Q000201:enzymology / Q000276:immunology; D047029:Lactams, Macrocyclic; D051379:Mice; D008807:Mice, Inbred BALB C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D009842:Oligopeptides / Q000494:pharmacology; D037342:Pertussis Toxin; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D011809:Quinones / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D017465:Receptors, Opioid, delta / Q000235:genetics* / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017828:Rifabutin / Q000031:analogs & derivatives; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D020703:ras GTPase-Activating Proteins; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D000276:Adjuvants, Immunologic; D016227:Benzoquinones; D002273:Carcinogens; D004791:Enzyme Inhibitors; D005419:Flavonoids; D020690:GTPase-Activating Proteins; D047029:Lactams, Macrocyclic; D009842:Oligopeptides; D011506:Proteins; D016760:Proto-Oncogene Proteins c-fos; D011809:Quinones; D012333:RNA, Messenger; D017465:Receptors, Opioid, delta; D010566:Virulence Factors, Bordetella; D020703:ras GTPase-Activating Proteins; C059567:deltorphin; D017828:Rifabutin; D016308:Enkephalin, Leucine-2-Alanine; C020754:herbimycin; D037342:Pertussis Toxin; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins; D013755:Tetradecanoylphorbol Acetate; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one