title: NAADP-induced Ca(2+ signaling in response to endothelin is via the receptor subtype B and requires the integrity of lipid rafts/caveolae.
abstract: We have investigated the role of NAADP-mediated Ca(2+) mobilization in endothelin (ET) signaling via endothelin receptor subtype A (ETA) and endothelin receptor subtype B (ETB) in rat peritubular smooth muscle cells. Microinjection and extracellular application of NAADP were both able to elicit Ca(2+) release which was blocked by inhibitory concentrations of NAADP, by impairing Ca(2+) uptake in acidic stores with bafilomycin, and by thapsigargin. Ca(2+) release in response to selective ETB stimulation was abolished by inhibition of NAADP signaling through the same strategies, while these treatments only partially impaired ETA-dependent Ca(2+) signaling, showing that transduction of the ETB signal is dependent on NAADP. In addition, we show that lipid rafts/caveolae contain ETA, ETB, and NAADP/cADPR generating enzyme CD38 and that stimulation of ETB receptors results in increased CD38 activity; interestingly, ETB- (but not ETA-) mediated Ca(2+) responses were antagonized by disruption of lipid rafts/caveolae with methyl-beta-cyclodextrin. These data demonstrate a primary role of NAADP in ETB-mediated Ca(2+) signaling and strongly suggest a novel role of lipid rafts/caveolae in triggering ET-induced NAADP signaling.
authors.affiliation: Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Histology and Medical Embryology, University of Rome La Sapienza, Rome, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Gambara
authors.forename: Richard A
authors.initials: RA
authors.lastname: Billington
authors.forename: Marcella
authors.initials: M
authors.lastname: Debidda
authors.forename: Alessio
authors.initials: A
authors.lastname: D'Alessio
authors.forename: Fioretta
authors.initials: F
authors.lastname: Palombi
authors.forename: Elio
authors.initials: E
authors.lastname: Ziparo
authors.forename: Armando A
authors.initials: AA
authors.lastname: Genazzani
authors.forename: Antonio
authors.initials: A
authors.lastname: Filippini
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1 / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D021941:Caveolae / Q000378:metabolism*; D051242:Caveolin 1 / Q000378:metabolism; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D016232:Endothelins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000502:physiology; D009249:NADP / Q000031:analogs & derivatives* / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D044022:Receptor, Endothelin A / Q000235:genetics / Q000378:metabolism*; D044023:Receptor, Endothelin B / Q000235:genetics / Q000378:metabolism*; D012671:Seminiferous Tubules / Q000166:cytology; D015398:Signal Transduction / Q000502:physiology; D047392:beta-Cyclodextrins / Q000378:metabolism
chemical_list: D051242:Caveolin 1; D019332:Endothelin-1; D016232:Endothelins; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; C074308:sovateltide; D009249:NADP; C024376:NAADP; D036541:ADP-ribosyl Cyclase; C498156:Cd38 protein, rat; D051997:ADP-ribosyl Cyclase 1; D002118:Calcium