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Investigating G protein signalling bias at the glucagon-like peptide-1 receptor in yeast.

Weston C, Poyner D, Patel V, Dowell S, Ladds G - Br. J. Pharmacol. (2014)

Bottom Line: This assay enables the study of individual ligand-receptor G protein coupling preferences and the quantification of the effect of GLP-1 receptor ligands on G protein selectivity.We obtained previously unobserved differences in G protein signalling bias for clinically relevant therapeutic agents, liraglutide and exenatide; the latter displaying significant bias for the Gαi pathway.These results provide a better understanding of the molecular events involved in GLP-1 receptor pleiotropic signalling and establish the yeast platform as a robust tool to screen for more selective, efficacious compounds acting at this important class of receptors in the future.

View Article: PubMed Central - PubMed

Affiliation: Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry, UK.

No MeSH data available.


Related in: MedlinePlus

Activation of the GLP-1 receptor by non-peptide ligands. Yeast strains expressing the GLP-1 receptor containing either the GPA1/Gαs or GPA1/Gαi chimera stimulated with a range of (A), compound 2 or (B), BETP concentrations for 20 h and reporter gene activity determined. Data expressed as a percentage of the maximum response achieved through activation of GPA1/Gαs. (C) To observe pathway preferences for each ligand, the normalized responses for equivalent concentrations of ligand were used to generate an equimolar bias plot; the dashed line represents no bias. All data are mean of five independent experiments ± SEM.
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fig06: Activation of the GLP-1 receptor by non-peptide ligands. Yeast strains expressing the GLP-1 receptor containing either the GPA1/Gαs or GPA1/Gαi chimera stimulated with a range of (A), compound 2 or (B), BETP concentrations for 20 h and reporter gene activity determined. Data expressed as a percentage of the maximum response achieved through activation of GPA1/Gαs. (C) To observe pathway preferences for each ligand, the normalized responses for equivalent concentrations of ligand were used to generate an equimolar bias plot; the dashed line represents no bias. All data are mean of five independent experiments ± SEM.

Mentions: Both compound 2 and BETP induced a dose-dependent increase in reporter gene activity following GLP-1 receptor stimulation (Figure 6A and B). The compound 2-induced response was significantly (P < 0.01, n = 6) influenced by the G protein chimera present displaying a reduced maximal response (Table 4) when coupled to the inhibitory pathway. In contrast, BETP agonism was not significantly (P > 0.05) affected by the G protein with EC50 values of 10 nM and 15 nM (Gαs and Gαi, respectively), this was confirmed through construction of an equimolar bias plot where the BETP data did not deviate from the no-bias line of unity (Figure 6C). These results provide a possible explanation for the observation that BETP displays partial agonism for GLP-1 receptor-mediated cAMP production in mammalian systems (Wootten et al., 2012) and demonstrate an intriguing insight into differences between the signalling of the two non-peptide ligands.


Investigating G protein signalling bias at the glucagon-like peptide-1 receptor in yeast.

Weston C, Poyner D, Patel V, Dowell S, Ladds G - Br. J. Pharmacol. (2014)

Activation of the GLP-1 receptor by non-peptide ligands. Yeast strains expressing the GLP-1 receptor containing either the GPA1/Gαs or GPA1/Gαi chimera stimulated with a range of (A), compound 2 or (B), BETP concentrations for 20 h and reporter gene activity determined. Data expressed as a percentage of the maximum response achieved through activation of GPA1/Gαs. (C) To observe pathway preferences for each ligand, the normalized responses for equivalent concentrations of ligand were used to generate an equimolar bias plot; the dashed line represents no bias. All data are mean of five independent experiments ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128063&req=5

fig06: Activation of the GLP-1 receptor by non-peptide ligands. Yeast strains expressing the GLP-1 receptor containing either the GPA1/Gαs or GPA1/Gαi chimera stimulated with a range of (A), compound 2 or (B), BETP concentrations for 20 h and reporter gene activity determined. Data expressed as a percentage of the maximum response achieved through activation of GPA1/Gαs. (C) To observe pathway preferences for each ligand, the normalized responses for equivalent concentrations of ligand were used to generate an equimolar bias plot; the dashed line represents no bias. All data are mean of five independent experiments ± SEM.
Mentions: Both compound 2 and BETP induced a dose-dependent increase in reporter gene activity following GLP-1 receptor stimulation (Figure 6A and B). The compound 2-induced response was significantly (P < 0.01, n = 6) influenced by the G protein chimera present displaying a reduced maximal response (Table 4) when coupled to the inhibitory pathway. In contrast, BETP agonism was not significantly (P > 0.05) affected by the G protein with EC50 values of 10 nM and 15 nM (Gαs and Gαi, respectively), this was confirmed through construction of an equimolar bias plot where the BETP data did not deviate from the no-bias line of unity (Figure 6C). These results provide a possible explanation for the observation that BETP displays partial agonism for GLP-1 receptor-mediated cAMP production in mammalian systems (Wootten et al., 2012) and demonstrate an intriguing insight into differences between the signalling of the two non-peptide ligands.

Bottom Line: This assay enables the study of individual ligand-receptor G protein coupling preferences and the quantification of the effect of GLP-1 receptor ligands on G protein selectivity.We obtained previously unobserved differences in G protein signalling bias for clinically relevant therapeutic agents, liraglutide and exenatide; the latter displaying significant bias for the Gαi pathway.These results provide a better understanding of the molecular events involved in GLP-1 receptor pleiotropic signalling and establish the yeast platform as a robust tool to screen for more selective, efficacious compounds acting at this important class of receptors in the future.

View Article: PubMed Central - PubMed

Affiliation: Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry, UK.

No MeSH data available.


Related in: MedlinePlus