[HTML][HTML] Real-time trafficking and signaling of the glucagon-like peptide-1 receptor

SN Roed, P Wismann, CR Underwood… - Molecular and cellular …, 2014 - Elsevier
SN Roed, P Wismann, CR Underwood, N Kulahin, H Iversen, KA Cappelen, L Schäffer…
Molecular and cellular endocrinology, 2014Elsevier
The glucagon-like peptide-1 incretin receptor (GLP-1R) of family BG protein-coupled
receptors (GPCRs) is a major drug target in type-2-diabetes due to its regulatory effect on
post-prandial blood-glucose levels. The mechanism (s) controlling GLP-1R mediated
signaling are far from fully understood. A fundamental mechanism controlling the signaling
capacity of GPCRs is the post-endocytic trafficking of receptors between recycling and
degradative fates. Here, we combined microscopy with novel real-time assays to monitor …
Abstract
The glucagon-like peptide-1 incretin receptor (GLP-1R) of family B G protein-coupled receptors (GPCRs) is a major drug target in type-2-diabetes due to its regulatory effect on post-prandial blood-glucose levels. The mechanism(s) controlling GLP-1R mediated signaling are far from fully understood. A fundamental mechanism controlling the signaling capacity of GPCRs is the post-endocytic trafficking of receptors between recycling and degradative fates. Here, we combined microscopy with novel real-time assays to monitor both receptor trafficking and signaling in living cells. We find that the human GLP-1R internalizes rapidly and with similar kinetics in response to equipotent concentrations of GLP-1 and the stable GLP-1 analogues exendin-4 and liraglutide. Receptor internalization was confirmed in mouse pancreatic islets. GLP-1R is shown to be a recycling receptor with faster recycling rates mediated by GLP-1 as compared to exendin-4 and liraglutide. Furthermore, a prolonged cycling of ligand-activated GLP-1Rs was observed and is suggested to be correlated with a prolonged cAMP signal.
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