title: Stimulation of secretion in permeabilized PC12 cells by adenosine 5'-[gamma-thio]triphosphate: possible involvement of nucleoside diphosphate kinase.
abstract: The addition of Ca2+, adenosine 5'-[gamma-thio]triphosphate (ATP[S]) or guanosine 5'-[gamma-thio]triphosphate (GTP[S]) to digitonin-permeabilized PC12 cells stimulates noradrenaline secretion. Both ATP[S] and GTP[S] stimulate release in the absence of Ca2+. Whereas ADP and adenosine 5'-[beta gamma-imido]triphosphate inhibited ATP[S]-stimulated release, they did not inhibit Ca(2+)-stimulated release even in the absence of added ATP. This suggests that the kinase which uses ATP[S] to induce secretion may not play an essential role in Ca(2+)-stimulated release. As GTP[S]-stimulated and ATP[S]-stimulated secretions were not additive, it seemed possible that stimulation by ATP[S] might in part result from the thiophosphorylation of GDP by nucleoside-diphosphate (NDP) kinase to form GTP[S]. The following results are consistent with this possibility. (1) A low concentration of GDP increased ATP[S]-stimulated secretion, but not GTP[S]-stimulated or Ca(2+)-stimulated secretion. (2) A variety of ribo- and deoxyribo-nucleoside di- and tri-phosphates inhibited ATP[S]-stimulated secretion, but not GTP[S]-stimulated or Ca(2+)-stimulated secretion. Thus, like NDP kinase, the kinase which uses ATP[S] to cause noradrenaline release appears to have a very low specificity for ATP. (3) Incubation of permeabilized cells in a sucrose-containing buffer resulted in the preferential loss of ATP[S]-stimulated secretion and a decrease in the level of NDP kinase. The addition of rat liver NDP kinase to those depleted cells partially restored ATP[S]-stimulated secretion.
authors.affiliation: Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
authors.forename: N D
authors.initials: ND
authors.lastname: Vu
authors.forename: P D
authors.initials: PD
authors.lastname: Wagner
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000502:physiology*; D004072:Digitonin; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007700:Kinetics; D009638:Norepinephrine / Q000378:metabolism*; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism*; D016716:PC12 Cells; D012265:Ribonucleotides / Q000494:pharmacology
chemical_list: D012265:Ribonucleotides; C022571:adenosine 5'-O-(3-thiotriphosphate); D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D009701:Nucleoside-Diphosphate Kinase; D004072:Digitonin; D002118:Calcium; D009638:Norepinephrine