title: Epoxyeicosatrienoic acid stimulates ADP-ribosylation of a 52 kDa protein in rat liver cytosol.
abstract: In rat liver cytosol, rapid ADP-ribosylation of a 52 kDa protein by endogenous ADP-ribosyltransferase(s) was observed. This ADP-ribosylation was stimulated dose-dependently by 14,15-epoxyeicosatrienoic acid (14,15-EET), one of the metabolites of arachidonic acid by NADPH-dependent cytochrome P-450 mono-oxygenase. This stimulatory effect required the presence of GTP or its non-hydrolysable analogues, guanosine 5'-[beta gamma-imido]triphosphate or guanosine 5'-[gamma-thio]triphosphate. Of four regioisomeric EETs, 14,15-EET was the most potent. No stimulatory effect was observed with addition of 14,15-dihydroxyeicosatrienoic acid, a stable metabolite of 14,15-EET. The 52 kDa protein was not ADP-ribosylated by cholera toxin A subunit and pertussis toxin, and was not recognized by anti-Gs alpha and anti-Gi alpha antibodies. However, the 52 kDa protein could be photoaffinity-labelled with 8-azidoguanosine 5'-[alpha-32P]triphosphate. These results suggest that the 52 kDa protein is neither Gs nor Gi, though it may have a GTP-binding site. These results contribute to the understanding of the role of mono-oxygenase metabolites of arachidonic acid in intracellular signal transduction.
authors.affiliation: 2nd Department of Internal Medicine, Chiba University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Seki
authors.forename: A
authors.initials: A
authors.lastname: Hirai
authors.forename: M
authors.initials: M
authors.lastname: Noda
authors.forename: Y
authors.initials: Y
authors.lastname: Tamura
authors.forename: I
authors.initials: I
authors.lastname: Kato
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000345:Affinity Labels; D000818:Animals; D001386:Azides; D002772:Cholera Toxin / Q000494:pharmacology; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D037342:Pertussis Toxin; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: C021961:8-azidoguanosine triphosphate; D000345:Affinity Labels; D001386:Azides; D011506:Proteins; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C046782:14,15-epoxy-5,8,11-eicosatrienoic acid; D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D037342:Pertussis Toxin; D015126:8,11,14-Eicosatrienoic Acid