PUBLICATION
Structural Mapping and Functional Characterization of Zebrafish Class B G-Protein Coupled Receptor (GPCR) with Dual Ligand Selectivity towards GLP-1 and Glucagon
- Authors
- Oren, D.A., Wei, Y., Skrabanek, L., Chow, B.K., Mommsen, T., Mojsov, S.
- ID
- ZDB-PUB-161209-1
- Date
- 2016
- Source
- PLoS One 11: e0167718 (Journal)
- Registered Authors
- Keywords
- Glucagon, Zebrafish, Crystal structure, Hydrogen bonding, G protein coupled receptors, Intracellular receptors, Protein sequencing, Sequence alignment
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Glucagon/metabolism*
- Glucagon-Like Peptide 1/metabolism*
- Ligands
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/metabolism*
- Sequence Homology, Amino Acid
- Zebrafish/metabolism*
- PubMed
- 27930690 Full text @ PLoS One
Citation
Oren, D.A., Wei, Y., Skrabanek, L., Chow, B.K., Mommsen, T., Mojsov, S. (2016) Structural Mapping and Functional Characterization of Zebrafish Class B G-Protein Coupled Receptor (GPCR) with Dual Ligand Selectivity towards GLP-1 and Glucagon. PLoS One. 11:e0167718.
Abstract
GLP-1 and glucagon regulate glucose metabolism through a network of metabolic pathways initiated upon binding to their specific receptors that belong to class B G-protein coupled receptors (GPCRs). The therapeutic potential of glucagon is currently being evaluated, while GLP-1 is already used in the treatment of type 2 diabetes and obesity. Development of a second generation of GLP-1 based therapeutics depends on a molecular and structural understanding of the interactions between the GLP-1 receptor (GLP-1R) and its ligand GLP-1. There is considerable sequence conservation between GLP-1 and glucagon and between the hGLP-1R and human glucagon receptor (hGCGR), yet each receptor recognizes only its own specific ligand. Glucagon receptors in fish and frogs also exhibit ligand selectivity only towards glucagon and not GLP-1. Based on competitive binding experiments and assays of increase in intracellular cAMP, we demonstrate here that a GPCR in zebrafish (Danio rerio) exhibits dual ligand selectivity towards GLP-1 and glucagon, a characteristic not found in mammals. Further, many structural features found in hGLP-1R and hGCGR are also found in this zebrafish GPCR (zfGPCR). We show this by mapping of its sequence and structural features onto the hGLP-1R and hGCGR based on their partial and complementary crystal structures. Thus, we propose that zfGPCR represents a dual GLP-1R/GCGR. The main differences between the three receptors are in their stalk regions that connect their N-terminal extracellular domains (NECDs) with their transmembrane domains and the absence of loop 3 in the NECD in zfGLP-1R/GCGR. These observations suggest that the interactions between GLP-1 and glucagon with loop 3 and the stalk regions may induce different conformational changes in hGLP-1R and hGCGR upon ligand binding and activation that lead to selective recognition of their native ligands.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping