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dc.contributor.authorAdams, Elizabeth
dc.date.accessioned2019-02-13T20:06:22Z
dc.date.available2019-02-13T20:06:22Z
dc.date.issued2/13/2019
dc.identifier.urihttp://hdl.handle.net/10675.2/622093
dc.descriptionPresentation given at the 20th Annual Phi Kappa Phi Student Research and Fine Arts Conferenceen
dc.description.abstractGPCRs play a major role in cell signaling through their interactions with heterotrimeric G proteins. In conventional models of GPCR-G protein coupling, agonist binding promotes a conformational change within the receptor, which then associates with G proteins, facilitating the exchange of GDP for GTP. GTP-bound G proteins dissociate from the receptor and exert their effects on downstream signaling molecules. Previous studies suggest that serotonin 5HT7 receptors associate with Gs�heterotrimers prior to agonist binding, and that 5HT7-Gs�complexes dissociate after the G protein is activated. Here we study this unconventional mode of coupling using bioluminescence resonance energy transfer (BRET) between luciferase-tagged 5HT7 receptors and Gs�heterotrimers labeled with Venus. Our results confirm that 5HT7 receptors interact with inactive (GDP-bound) Gs�heterotrimers in the absence of an agonist, and that this interaction is stabilized by the inverse agonist methiothepin. Stimulation with the endogenous agonist serotonin (5HT) decreased BRET between 5HT7 receptors and Gs, indicating that the activation of the receptor leads to 5HT7-Gscomplex dissociation. Interestingly, Gs�activation was not required for complex dissociation. These results are consistent with the hypothesis that 5HT7 receptors couple to Gs�heterotrimers via an unconventional mechanism involving ligand-sensitive complexes of receptors and inactive Gs.
dc.subjectGPCRsen
dc.subjectBRETen
dc.subjectserotonin receptorsen
dc.titleUnconventional Coupling of 5HT7 receptors to Gs heterotrimersen
dc.typeOral Presentationen
dc.contributor.departmentDepartment of Pharmacology and Toxicologyen
cr.funding.sourceAugusta University CURS Student Research Granten
dc.contributor.affiliationAugusta Universityen
dc.contributor.sponsorLambert, Nevinen
html.description.abstractGPCRs play a major role in cell signaling through their interactions with heterotrimeric G proteins. In conventional models of GPCR-G protein coupling, agonist binding promotes a conformational change within the receptor, which then associates with G proteins, facilitating the exchange of GDP for GTP. GTP-bound G proteins dissociate from the receptor and exert their effects on downstream signaling molecules. Previous studies suggest that serotonin 5HT7 receptors associate with Gs�heterotrimers prior to agonist binding, and that 5HT7-Gs�complexes dissociate after the G protein is activated. Here we study this unconventional mode of coupling using bioluminescence resonance energy transfer (BRET) between luciferase-tagged 5HT7 receptors and Gs�heterotrimers labeled with Venus. Our results confirm that 5HT7 receptors interact with inactive (GDP-bound) Gs�heterotrimers in the absence of an agonist, and that this interaction is stabilized by the inverse agonist methiothepin. Stimulation with the endogenous agonist serotonin (5HT) decreased BRET between 5HT7 receptors and Gs, indicating that the activation of the receptor leads to 5HT7-Gscomplex dissociation. Interestingly, Gs�activation was not required for complex dissociation. These results are consistent with the hypothesis that 5HT7 receptors couple to Gs�heterotrimers via an unconventional mechanism involving ligand-sensitive complexes of receptors and inactive Gs.


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