title: Synergistic activation of phospholipases Cgamma and Cbeta: a novel mechanism for PI3K-independent enhancement of FcepsilonRI-induced mast cell mediator release.
abstract: Antigen/IgE-mediated mast cell activation via FcvarepsilonRI can be markedly enhanced by the activation of other receptors expressed on mast cells and these receptors may thus contribute to the allergic response in vivo. One such receptor family is the G protein-coupled receptors (GPCRs). Although the signaling cascade linking FcvarepsilonRI aggregation to mast cell activation has been extensively investigated, the mechanisms by which GPCRs amplify this response are relatively unknown. To investigate this, we utilized prostaglandin (PG)E2 based on initial studies demonstrating its greater ability to augment antigen-mediated degranulation in mouse mast cells than other GPCR agonists examined. This enhancement, and the ability of PGE2 to amplify antigen-induced calcium mobilization, was independent of phosphoinositide 3-kinase but was linked to a pertussis toxin-sensitive synergistic translocation to the membrane of phospholipase (PL)Cgamma and PLCbeta and to an enhancement of PLCgamma phosphorylation. This "trans-synergistic" activation of PLCbeta and gamma, in turn, enhanced production of inositol 1,4,5-trisphosphate, store-operated calcium entry, and activation of protein kinase C (PKC) (alpha and beta). These responses were critical for the promotion of degranulation. This is the first report of synergistic activation between PLCgamma and PLCbeta that permits reinforcement of signals for degranulation in mast cells.
authors.affiliation: Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 10 Center Drive MSC 1881, Bethesda, MD 20892-1881, USA.
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Kuehn
authors.forename: Michael A
authors.initials: MA
authors.lastname: Beaven
authors.forename: Hong-Tao
authors.initials: HT
authors.lastname: Ma
authors.forename: Mi-Sun
authors.initials: MS
authors.lastname: Kim
authors.forename: Dean D
authors.initials: DD
authors.lastname: Metcalfe
authors.forename: Alasdair M
authors.initials: AM
authors.lastname: Gilfillan
mesh_terms: D000818:Animals; D000941:Antigens / Q000378:metabolism*; D020013:Calcium Signaling; D015550:Cell Degranulation / Q000187:drug effects / Q000276:immunology; D002462:Cell Membrane / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D004789:Enzyme Activation; D006967:Hypersensitivity / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D037342:Pertussis Toxin / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D054799:Phospholipase C beta / Q000378:metabolism*; D051966:Phospholipase C gamma / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha / Q000378:metabolism; D021381:Protein Transport; D011940:Receptor Aggregation; D020239:Receptor Cross-Talk; D017455:Receptors, IgE / Q000378:metabolism*; D018078:Receptors, Prostaglandin E / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D013997:Time Factors
chemical_list: D000941:Antigens; D016207:Cytokines; D017455:Receptors, IgE; D018078:Receptors, Prostaglandin E; D015544:Inositol 1,4,5-Trisphosphate; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D054799:Phospholipase C beta; D051966:Phospholipase C gamma; D015232:Dinoprostone