title: Human phosphatidylethanolamine-binding protein facilitates heterotrimeric G protein-dependent signaling.
abstract: In this study we report that human phosphatidylethanolamine-binding protein (hPBP) facilitates heterotrimeric G protein-coupled signaling. In Xenopus laevis oocytes, coexpression of hPBP with human mu opioid receptor, human delta opioid receptor, or human somatostatin receptor 2 evoked an agonist-induced increase in potassium conductance of G protein-activated inwardly rectifying potassium channels. This activation of heterotrimeric G protein signaling in oocytes could also be elicited by injection of bacterially overexpressed and purified hPBP. Stimulatory effect was pertussis toxin-sensitive and present even in the absence of coexpressed receptors. Additionally, an increase in G protein-mediated inhibition of adenylate cyclase activity, measured by the inhibition of forskolin-mediated cAMP accumulation, could be detected in HEK293 and NIH3T3 cells after expression of hPBP and in Xenopus oocytes after injection of hPBP. As [(35)S]guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) binding to membranes prepared from hPBP-expressing cells was significantly elevated and recombinant hPBP dose-dependently stimulated [(35)S]GTPgammaS binding to native membranes, the results presented provide strong evidence that hPBP-induced effects are G protein-dependent. These data suggest a novel function of hPBP in regulating G protein and G protein-coupled receptor signaling in vivo.
authors.affiliation: Institute of Pharmacology and Toxicology, Otto-von-Guericke University of Magdeburg, Leipzigerstrasse 44, D-39120 Magdeburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Kroslak
authors.forename: T
authors.initials: T
authors.lastname: Koch
authors.forename: E
authors.initials: E
authors.lastname: Kahl
authors.forename: V
authors.initials: V
authors.lastname: Höllt
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000727:Androgen-Binding Protein; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism; D017124:Conserved Sequence; D000242:Cyclic AMP / Q000378:metabolism; D004553:Electric Conductivity; D005260:Female; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes; D049488:Phosphatidylethanolamine Binding Protein; D049294:Phospholipid Transfer Proteins; D011188:Potassium / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000819:agonists / Q000378:metabolism; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu / Q000378:metabolism; D017481:Receptors, Somatostatin / Q000378:metabolism; D015398:Signal Transduction; D014981:Xenopus
chemical_list: D000727:Androgen-Binding Protein; D002352:Carrier Proteins; D002712:Chlorides; C511482:PEBP1 protein, human; D049488:Phosphatidylethanolamine Binding Protein; D049294:Phospholipid Transfer Proteins; D024661:Potassium Channels, Inwardly Rectifying; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D017481:Receptors, Somatostatin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C093733:somatostatin receptor 2; D000242:Cyclic AMP; D020962:Heterotrimeric GTP-Binding Proteins; D011188:Potassium; D002118:Calcium