RGD Reference Report - Coupling of oxytocin receptor to G proteins in rat myometrium during labor: Gi receptor interaction. - Rat Genome Database

Send us a Message
Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   
Search RGD Grant Resources Citing RGD About Us Contact Us
Genes Variants Community Projects QTLs Strains Markers Genome Information Ontologies Cell Lines References Download Submit Data
OntoMate (Literature Search) JBrowse (Genome Browser) Synteny Browser (VCMap) Variant Visualizer Multi-Ontology Enrichment (MOET) Gene-Ortholog Location Finder (GOLF) InterViewer (Protein-Protein Interactions) PhenoMiner (Quatitative Phenotypes) Gene Annotator OLGA (Gene List Generator) AllianceMine GViewer (Genome Viewer)
Aging & Age-Related Disease Cancer & Neoplastic Disease Cardiovascular Disease Coronavirus Disease Developmental Disease Diabetes Hematologic Disease Immune & Inflammatory Disease Infectious Disease Liver Disease Neurological Disease Obesity & Metabolic Syndrome Renal Disease Respiratory Disease Sensory Organ Disease
Find Models   new Genetic Models Autism Models Rat PhenoMiner (Quantitative Phenotypes) Chinchilla PhenoMiner Expected Ranges (Quantitative Phenotype) PhenoMiner Term Comparison Hybrid Rat Diversity Panel Phenotypes Phenotypes in Other Animal Models Animal Husbandry Strain Medical Records Phylogenetics Strain Availability Calendar Rats 101 Submissions Photo Archive
Pathways
Rat Community Forum Directory of Rat Laboratories Video Tutorials News RGD Publications RGD Presentations Archive Nomenclature Guidelines Resource Links Laboratory Resources Employment Resources

Coupling of oxytocin receptor to G proteins in rat myometrium during labor: Gi receptor interaction.

Authors: Strakova, Z  Soloff, MS 
Citation: Strakova Z and Soloff MS, Am J Physiol. 1997 May;272(5 Pt 1):E870-6.
RGD ID: 4890391
Pubmed: PMID:9176188   (View Abstract at PubMed)

Occupancy of oxytocin receptor (OTR) binding sites in pregnant rat myometrial membranes with iodinated oxytocin antagonist (OTA), followed by detergent solubilization and size selection, showed that radioactivity eluted in two distinct peaks: one corresponding in size to the isolated receptor (approximately 60 kDa) and the other ranging from 240 to 320 kDa. The unliganded 240- to 320-kDa fraction contained OTRs coupled to G proteins, as the addition of oxytocin (OT) increased guanosine 35S-labeled 5'-O-(3-thiotriphosphate) binding up to twofold in a dose-dependent manner. The effects of OT were blocked by coincubation with OTA. G protein alpha-subunits associated with OTRs in the 240- to 320-kDa peak were identified by immunoadsorption. Significant amounts of both G alpha q/11 and G alpha i3 were associated with the OTR; a lesser amount of G alpha s was complexed. Using the same approach but with antibodies to effector enzymes, we observed that phospholipase C beta 1 (PLC beta 1) and PLA2 were also associated with the OTR. The results corroborate the well-established interaction of OTR with Gq and further show that Gi coupling might be an important component of OTR signal transduction. To further investigate the interaction of Gi with the OTR, we showed that OT stimulation of guanosine 5'-triphosphatase activity in intact myometrial membranes was inhibited by pertussis toxin. Pertussis toxin-stimulated ADP ribosylation of G alpha i in myometrial membranes was also decreased by OT treatment. These findings with pertussis toxin strongly indicate that OTR is coupled to Gi in rat myometrial membranes. The 60-kDa OTR peak (noncoupled receptor) was demonstrable in the myometrium only before the end of gestation and after parturition and accounted for about one-half the 125I-OTA binding activity. At term, there was about a fivefold increase in binding and almost a complete shift to the 240- to 320-kDa-size complex. Thus the established increased sensitivity of the myometrium to OT at term could be the result of both upregulation of OTRs and an increase in the fraction of receptors coupled to signal transduction components, one of which is Gi.

Gene Ontology Annotations    Click to see Annotation Detail View

Molecular Function
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
protein binding  IPIOxtr (Rattus norvegicus)4890391 RGD 
protein binding  IPIGnai3 (Rattus norvegicus)4890391 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Gnai3  (G protein subunit alpha i3)
Oxtr  (oxytocin receptor)


Additional Information