scholarly journals The putative signal peptide of glucagon-like peptide-1 receptor is not required for receptor synthesis but promotes receptor expression

2014 ◽  
Vol 34 (6) ◽  
Author(s):  
Yunjun Ge ◽  
Dehua Yang ◽  
Antao Dai ◽  
Caihong Zhou ◽  
Yue Zhu ◽  
...  
Keyword(s):  
Signal Peptide ◽  
Receptor Expression ◽  
Hek293 Cells ◽  
Putative Signal Peptide ◽  
293 Cells ◽  
Class B ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
G Protein Coupled

GLP-1R (glucagon-like peptide-1 receptor) mediates the ‘incretin effect’ and many other anti-diabetic actions of its cognate ligand, GLP-1 (glucagon-like peptide-1). It belongs to the class B family of GPCRs (G protein-coupled receptors) and possesses an N-terminal putative SP (signal peptide). It has been reported that this sequence is required for the synthesis of GLP-1R and is cleaved after receptor synthesis. In the present study, we conducted an in-depth exploration towards the role of the putative SP in GLP-1R synthesis. A mutant GLP-1R without this sequence was expressed in HEK293 cells (human embryonic kidney 293 cells) and displayed normal functionality with respect to ligand binding and activation of adenylate cyclase. Thus the putative SP does not seem to be required for receptor synthesis. Immunoblotting analysis shows that the amount of GLP-1R synthesized in HEK293 cells is low when the putative SP is absent. This indicates that the role of the sequence is to promote the expression of GLP-1R. Furthermore, epitopes tagged at the N-terminal of GLP-1R are detectable by immunofluorescence and immunoblotting in our experiments. In conclusion, the present study points to different roles of SP in GLP-1R expression which broadens our understanding of the functionality of this putative SP of GLP-1R and possibly other Class B GPCRs.

scholarly journals The Interplay of Glucagon-Like Peptide-1 Receptor Trafficking and Signalling in Pancreatic Beta Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Amaara Marzook ◽  
Alejandra Tomas ◽  
Ben Jones
Keyword(s):  
Pancreatic Beta Cells ◽  
Metabolic Effects ◽  
Physiological Importance ◽  
Intracellular Signals ◽  
Class B ◽  
The Central Nervous System ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
G Protein Coupled

The glucagon-like peptide 1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) which mediates the effects of GLP-1, an incretin hormone secreted primarily from L-cells in the intestine and within the central nervous system. The GLP-1R, upon activation, exerts several metabolic effects including the release of insulin and suppression of appetite, and has, accordingly, become an important target for the treatment for type 2 diabetes (T2D). Recently, there has been heightened interest in how the activated GLP-1R is trafficked between different endomembrane compartments, controlling the spatial origin and duration of intracellular signals. The discovery of “biased” GLP-1R agonists that show altered trafficking profiles and selective engagement with different intracellular effectors has added to the tools available to study the mechanisms and physiological importance of these processes. In this review we survey early and recent work that has shed light on the interplay between GLP-1R signalling and trafficking, and how it might be therapeutically tractable for T2D and related diseases.

scholarly journals Glucagon-Like Peptide-1 and Its Class B G Protein–Coupled Receptors: A Long March to Therapeutic Successes

2016 ◽  
Vol 68 (4) ◽  
pp. 954-1013 ◽  
Author(s):  
Chris de Graaf ◽  
Dan Donnelly ◽  
Denise Wootten ◽  
Jesper Lau ◽  
Patrick M. Sexton ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Class B ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
G Protein Coupled

scholarly journals The role of apolipoprotein A-IV in regulating glucagon-like peptide-1 secretion

2015 ◽  
Vol 309 (8) ◽  
pp. G680-G687 ◽  
Author(s):  
Fei Wang ◽  
Qing Yang ◽  
Sarah Huesman ◽  
Min Xu ◽  
Xiaoming Li ◽  
...  
Keyword(s):  
Potential Mechanism ◽  
Wild Type ◽  
Apolipoprotein A ◽  
Intestinal Segments ◽  
Saline Administration ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
G Protein Coupled ◽  
Postprandial Insulin

Both glucagon-like peptide-1 (GLP-1) and apolipoprotein A-IV (apoA-IV) are produced from the gut and enhance postprandial insulin secretion. This study investigated whether apoA-IV regulates nutrient-induced GLP-1 secretion and whether apoA-IV knockout causes compensatory GLP-1 release. Using lymph-fistula-mice, we first determined lymphatic GLP-1 secretion by administering apoA-IV before an intraduodenal Ensure infusion. apoA-IV changed neither basal nor Ensure-induced GLP-1 secretion relative to saline administration. We then assessed GLP-1 in apoA-IV−/− and wild-type (WT) mice administered intraduodenal Ensure. apoA-IV−/− mice had comparable lymph flow, lymphatic triglyceride, glucose, and protein outputs as WT mice. Intriguingly, apoA-IV−/− mice had higher lymphatic GLP-1 concentration and output than WT mice 30 min after Ensure administration. Increased GLP-1 was also observed in plasma of apoA-IV−/− mice at 30 min. apoA-IV−/− mice had comparable total gut GLP-1 content relative to WT mice under fasting, but a lower GLP-1 content 30 min after Ensure administration, suggesting that more GLP-1 was secreted. Moreover, an injection of apoA-IV protein did not reverse the increased GLP-1 secretion in apoA-IV−/− mice. Finally, we assessed gene expression of GLUT-2 and the lipid receptors, including G protein-coupled receptor (GPR) 40, GPR119, and GPR120 in intestinal segments. GLUT-2, GPR40 and GPR120 mRNAs were unaltered by apoA-IV knockout. However, ileal GPR119 mRNA was significantly increased in apoA-IV−/− mice. GPR119 colocalizes with GLP-1 in ileum and stimulates GLP-1 secretion by sensing OEA, lysophosphatidylcholine, and 2-monoacylglycerols. We suggest that increased ileal GPR119 is a potential mechanism by which GLP-1 secretion is enhanced in apoA-IV−/− mice.

Investigation of ECD conformational transition mechanism of GLP-1R by molecular dynamics simulations and Markov state model

2019 ◽  
Vol 21 (16) ◽  
pp. 8470-8481 ◽  
Author(s):  
Jintu Zhang ◽  
Qifeng Bai ◽  
Horacio Pérez-Sánchez ◽  
Shuxia Shang ◽  
Xiaoli An ◽  
...  
Keyword(s):  
Conformational Transition ◽  
G Protein Coupled Receptors ◽  
Markov State Model ◽  
Markov State ◽  
Transition Mechanism ◽  
Class B ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Dynamics Simulations ◽  
G Protein Coupled

As a member of the class B G protein-coupled receptors (GPCRs), the glucagon-like peptide-1 (GLP-1) can regulate the blood glucose level by binding to the glucagon-like peptide-1 receptor (GLP-1R).

Bioinformatics Analysis and Validation of Differentially Expressed MicroRNAs with Their Target Genes Involved in GLP-1RA Facilitated Osteogenesis

2020 ◽  
Vol 15 ◽  
Author(s):  
Na Wang ◽  
Yukun Li ◽  
Sijing Liu ◽  
Liu Gao ◽  
Chang Liu ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Target Genes ◽  
Bioinformatics Analysis ◽  
Differentially Expressed ◽  
Functional Study ◽  
Regulation Network ◽  
Glucagon Like Peptide 1 ◽  
G Protein Coupled ◽  
Lower Expression

Background: Recent studies revealed that the hypoglycemic hormone, glucagon-like peptide-1 (GLP-1), acted as an important modulator in osteogenesis of bone marrow derived mesenchymal stem cells (BMSCs). Objectives: The aim of this study was to identify the specific microRNA (miRNA) using bioinformatics analysis and validate the presence of differentially expressed microRNAs with their target genes after GLP-1 receptor agonist (GLP-1RA) administration involved in ostogenesis of BMSCs. Methods: MiRNAs were extracted from BMSCs after 5 days’ treatment and sent for high-throughput sequencing for differentially expressed (DE) miRNAs analyses. Then the expression of the DE miRNAs verified by the real-time RT-PCR analyses. Target genes were predicted, and highly enriched GOs and KEGG pathway analysis were conducted using bioinformatics analysis. For the functional study, two of the target genes, SRY (sex determining region Y)-box 5 (SOX5) and G protein-coupled receptor 84 (GPR84), were identified. Results: A total of 5 miRNAs (miRNA-509-5p, miRNA-547-3p, miRNA-201-3p, miRNA-201-5p, and miRNA-novel-272-mature) were identified differentially expressed among groups. The expression of miRNA-novel-272-mature were decreased during the osteogenic differentiation of BMSCs, and GLP-1RA further decreased its expression. MiRNA-novel-272-mature might interact with its target mRNAs to enhance osteogenesis. The lower expression of miRNA-novel-272-mature led to an increase in SOX5 and a decrease in GPR84 mRNA expression, respectively. Conclusions: Taken together, these results provide further insights to the pharmacological properties of GLP-1RA and expand our knowledge on the role of miRNAs-mRNAs regulation network in BMSCs’ differentiation.

scholarly journals Bile acids drive colonic secretion of glucagon-like-peptide 1 and peptide-YY in rodents

2019 ◽  
Vol 316 (5) ◽  
pp. G574-G584 ◽  
Author(s):  
Charlotte Bayer Christiansen ◽  
Samuel Addison Jack Trammell ◽  
Nicolai Jacob Wewer Albrechtsen ◽  
Kristina Schoonjans ◽  
Reidar Albrechtsen ◽  
...  
Keyword(s):  
Bile Acids ◽  
G Protein ◽  
Peptide Yy ◽  
Whole Body ◽  
Rat Colon ◽  
G Protein Coupled Receptor ◽  
L Cells ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
G Protein Coupled

A large number of glucagon-like-peptide-1 (GLP-1)- and peptide-YY (PYY)-producing L cells are located in the colon, but little is known about their contribution to whole body metabolism. Since bile acids (BAs) increase GLP-1 and PYY release, and since BAs spill over from the ileum to the colon, we decided to investigate the ability of BAs to stimulate colonic GLP-1 and PYY secretion. Using isolated perfused rat/mouse colon as well as stimulation of the rat colon in vivo, we demonstrate that BAs significantly enhance secretion of GLP-1 and PYY from the colon with average increases of 3.5- and 2.9-fold, respectively. Furthermore, we find that responses depend on BA absorption followed by basolateral activation of the BA-receptor Takeda-G protein-coupled-receptor 5. Surprisingly, the apical sodium-dependent BA transporter, which serves to absorb conjugated BAs, was not required for colonic conjugated BA absorption or conjugated BA-induced peptide secretion. In conclusion, we demonstrate that BAs represent a major physiological stimulus for colonic L-cell secretion.NEW & NOTEWORTHY By the use of isolated perfused rodent colon preparations we show that bile acids are potent and direct promoters of colonic glucagon-like-peptide 1 and peptide-YY secretion. The study provides convincing evidence that basolateral Takeda-G protein-coupled-receptor 5 activation is mediating the effects of bile acids in the colon and thus add to the existing literature described for L cells in the ileum.

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