title: Role of a guanine nucleotide-binding protein in alpha 1-adrenergic receptor-mediated Ca2+ mobilization in DDT1 MF-2 cells.
abstract: In this study the mechanisms involved in alpha 1-adrenergic receptor-mediated Ca2+ mobilization at the level of the plasma membrane were investigated. Stimulation of 45Ca2+ efflux from saponin-permeabilized DDT1 MF-2 cells was observed with the addition of either the alpha 1-adrenergic agonist phenylephrine and guanosine-5'-triphosphate or the nonhydrolyzable guanine nucleotide guanylyl-imidodiphosphate. In the presence of [32P]NAD, pertussis toxin was found to catalyze ADP-ribosylation of a Mr = 40,500 (n = 8) peptide in membranes prepared from DDT1 MF-2 cells, possibly the alpha-subunit of Ni. However, stimulation of unidirectional 45Ca2+ efflux by phenylephrine was not affected by previous treatment of cells with 100 ng/ml pertussis toxin. These data suggest that the putative guanine nucleotide-binding protein which couples the alpha 1-adrenergic receptor to Ca2+ mobilization in DDT1 MF-2 cells is not a pertussis toxin substrate and may possibly be an additional member of the guanine nucleotide binding protein family.
authors.affiliation: Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock 72205-7199.
authors.forename: L E
authors.initials: LE
authors.lastname: Cornett
authors.forename: J S
authors.initials: JS
authors.lastname: Norris
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D008970:Molecular Weight; D009130:Muscle, Smooth / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D037342:Pertussis Toxin; D010656:Phenylephrine / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D012503:Saponins / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D011942:Receptors, Adrenergic, alpha; D012503:Saponins; D010566:Virulence Factors, Bordetella; D009243:NAD; D010656:Phenylephrine; D000246:Adenosine Diphosphate Ribose; D006160:Guanosine Triphosphate; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D002118:Calcium