scholarly journals Concerted conformational dynamics and water movements in the ghrelin G protein-coupled receptor

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Maxime Louet ◽  
Marina Casiraghi ◽  
Marjorie Damian ◽  
Mauricio GS Costa ◽  
Pedro Renault ◽  
...  
Keyword(s):  
G Protein ◽  
Unnatural Amino Acids ◽  
Conformational Dynamics ◽  
Signal Propagation ◽  
Water Molecules ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Ghrelin Receptor ◽  
Tightly Coupled ◽  
G Protein Coupled

There is increasing support for water molecules playing a role in signal propagation through G protein-coupled receptors (GPCRs). However, exploration of the hydration features of GPCRs is still in its infancy. Here, we combined site-specific labeling with unnatural amino acids to molecular dynamics to delineate how local hydration of the ghrelin receptor growth hormone secretagogue receptor (GHSR) is rearranged upon activation. We found that GHSR is characterized by a specific hydration pattern that is selectively remodeled by pharmacologically distinct ligands and by the lipid environment. This process is directly related to the concerted movements of the transmembrane domains of the receptor. These results demonstrate that the conformational dynamics of GHSR are tightly coupled to the movements of internal water molecules, further enhancing our understanding of the molecular bases of GPCR-mediated signaling.

G protein-coupled receptor 120 signaling regulates ghrelin secretion in vivo and in vitro

2014 ◽  
Vol 306 (1) ◽  
pp. E28-E35 ◽  
Author(s):  
Zhi Gong ◽  
Makoto Yoshimura ◽  
Sayaka Aizawa ◽  
Reiko Kurotani ◽  
Jeffrey M. Zigman ◽  
...  
Keyword(s):  
G Protein ◽  
Cell Lines ◽  
G Protein Coupled Receptor ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Expression Levels ◽  
Ghrelin Secretion ◽  
G Protein Coupled

Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, is produced predominantly in the stomach. It has been reported that endogenous ghrelin levels are increased by fasting and decreased immediately after feeding and that fasting-induced ghrelin release is controlled by the sympathetic nervous system. However, the mechanisms of plasma ghrelin decrement after feeding are poorly understood. Here, we studied the control of ghrelin secretion using ghrelin-producing cell lines and found that these cells express high levels of mRNA encoding G-protein coupled receptor 120 (GPR120). Addition of GW-9508 (a GPR120 chemical agonist) and α-linolenic acid (a natural ligand for GPR120) inhibited the secretion of ghrelin by ∼50 and 70%, respectively. However, the expression levels of preproghrelin and ghrelin O-acyltransferase (GOAT) mRNAs were not influenced by GW-9508. In contrast, the expression levels of prohormone convertase 1 were decreased significantly by GW-9508 incubation. Moreover, we observed that the inhibitory effect of GW-9508 on ghrelin secretion was blocked by a small interfering RNA (siRNA) targeting the sequence of GPR120. Furthermore, pretreatment with GW-9508 blocked the effect of the norepinephrine (NE)-induced ghrelin elevation in ghrelin cell lines. In addition, we showed that GW-9508 inhibited ghrelin secretion via extracellular signal-regulated kinase activity in ghrelin cell lines. Finally, we found that GW-9508 decreased plasma ghrelin levels in mice. These results suggest that the decrease of ghrelin secretion after feeding is induced partially by long-chain fatty acids that act directly on gastric GPR120-expressing ghrelin cells.

scholarly journals Structural Requirements for the Activation of the Human Growth Hormone Secretagogue Receptor by Peptide and Nonpeptide Secretagogues

1998 ◽  
Vol 12 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Scott D. Feighner ◽  
Andrew D. Howard ◽  
Kristine Prendergast ◽  
Oksana C. Palyha ◽  
Donna L. Hreniuk ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Binding Site ◽  
G Protein ◽  
Human Growth ◽  
G Protein Coupled Receptors ◽  
Site Directed Mutagenesis ◽  
Agonist Binding ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
G Protein Coupled

Abstract Antibodies raised against an intracellular and extracellular domain of the GH secretagogue receptor (GHS-R) confirmed that its topological orientation in the lipid bilayer is as predicted for G protein-coupled receptors with seven transmembrane domains. A strategy for mapping the agonist-binding site of the human GHS-R was conceived based on our understanding of ligand binding in biogenic amine and peptide hormone G protein-coupled receptors. Using site-directed mutagenesis and molecular modeling, we classified GHS peptide and nonpeptide agonist binding in the context of its receptor environment. All peptide and nonpeptide ligand classes shared a common binding domain in transmembrane (TM) region 3 of the GHS-R. This finding was based on TM-3 mutation E124Q, which eliminated the counter-ion to the shared basic N+ group of all GHSs and resulted in a nonfunctional receptor. Restoration of function for the E124Q mutant was achieved by a complementary change in the MK-0677 ligand through modification of its amine side-chain to the corresponding alcohol. Contacts in other TM domains [TM-2 (D99N), TM-5 (M213K, S117A), TM-6 (H280F), and extracellular loop 1 (C116A)] of the receptor revealed specificity for the different peptide, benzolactam, and spiroindolane GHSs. GHS-R agonism, therefore, does not require identical disposition of all agonist classes at the ligand-binding site. Our results support the hypothesis that the ligand-binding pocket in the GHS-R is spatially disposed similarly to the well characterized catechol-binding site in theβ 2-adrenergic receptor.

scholarly journals Structure and dynamics of G protein-coupled receptor–bound ghrelin reveal the critical role of the octanoyl chain

2019 ◽  
Vol 116 (35) ◽  
pp. 17525-17530 ◽  
Author(s):  
Guillaume Ferré ◽  
Maxime Louet ◽  
Oliver Saurel ◽  
Bartholomé Delort ◽  
Georges Czaplicki ◽  
...  
Keyword(s):  
G Protein ◽  
Critical Role ◽  
Conformational Space ◽  
Coarse Grained ◽  
Hydrophobic Core ◽  
G Protein Coupled Receptor ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Structure And Dynamics ◽  
G Protein Coupled

Ghrelin plays a central role in controlling major biological processes. As for other G protein-coupled receptor (GPCR) peptide agonists, the structure and dynamics of ghrelin bound to its receptor remain obscure. Using a combination of solution-state NMR and molecular modeling, we demonstrate that binding to the growth hormone secretagogue receptor is accompanied by a conformational change in ghrelin that structures its central region, involving the formation of a well-defined hydrophobic core. By comparing its acylated and nonacylated forms, we conclude that the ghrelin octanoyl chain is essential to form the hydrophobic core and promote access of ghrelin to the receptor ligand-binding pocket. The combination of coarse-grained molecular dynamics studies and NMR should prove useful in improving our mechanistic understanding of the complex conformational space explored by a natural peptide agonist when binding to its GPCR. Such information should also facilitate the design of new ghrelin receptor-selective drugs.

scholarly journals Ghrelin receptor conformational dynamics regulate the transition from a preassembled to an active receptor:Gq complex

2015 ◽  
Vol 112 (5) ◽  
pp. 1601-1606 ◽  
Author(s):  
Marjorie Damian ◽  
Sophie Mary ◽  
Mathieu Maingot ◽  
Céline M'Kadmi ◽  
Didier Gagne ◽  
...  
Keyword(s):  
G Protein ◽  
Unnatural Amino Acids ◽  
Conformational Dynamics ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Active Conformation ◽  
Ghrelin Receptor ◽  
Protein Activation ◽  
G Protein Activation ◽  
Open Question

How G protein-coupled receptor conformational dynamics control G protein coupling to trigger signaling is a key but still open question. We addressed this question with a model system composed of the purified ghrelin receptor assembled into lipid discs. Combining receptor labeling through genetic incorporation of unnatural amino acids, lanthanide resonance energy transfer, and normal mode analyses, we directly demonstrate the occurrence of two distinct receptor:Gq assemblies with different geometries whose relative populations parallel the activation state of the receptor. The first of these assemblies is a preassembled complex with the receptor in its basal conformation. This complex is specific of Gq and is not observed with Gi. The second one is an active assembly in which the receptor in its active conformation triggers G protein activation. The active complex is present even in the absence of agonist, in a direct relationship with the high constitutive activity of the ghrelin receptor. These data provide direct evidence of a mechanism for ghrelin receptor-mediated Gq signaling in which transition of the receptor from an inactive to an active conformation is accompanied by a rearrangement of a preassembled receptor:G protein complex, ultimately leading to G protein activation and signaling.

scholarly journals Cannabinoid-Induced Conditioned Place Preference, Intravenous Self-Administration, and Behavioral Stimulation Influenced by Ghrelin Receptor Antagonism in Rats

2021 ◽  
Vol 22 (5) ◽  
pp. 2397
Author(s):  
Chrysostomos Charalambous ◽  
Tereza Havlickova ◽  
Marek Lapka ◽  
Nina Puskina ◽  
Romana Šlamberová ◽  
...  
Keyword(s):  
Conditioned Place Preference ◽  
Fixed Ratio ◽  
Place Preference ◽  
Self Administration ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Ghrelin Receptor ◽  
Addiction Therapy ◽  
Significant Efficacy ◽  
Lever Pressing

Cannabis/cannabinoids are widely used for recreational and therapy purposes, but their risks are largely disregarded. However, cannabinoid-associated use disorders and dependence are alarmingly increasing and an effective treatment is lacking. Recently, the growth hormone secretagogue receptor (GHSR1A) antagonism was proposed as a promising mechanism for drug addiction therapy. However, the role of GHS-R1A and its endogenous ligand ghrelin in cannabinoid abuse remains unclear. Therefore, the aim of our study was to investigate whether the GHS-R1A antagonist JMV2959 could reduce the tetrahydrocannabinol (THC)-induced conditioned place preference (CPP) and behavioral stimulation, the WIN55,212-2 intravenous self-administration (IVSA), and the tendency to relapse. Following an ongoing WIN55,212-2 self-administration, JMV2959 3 mg/kg was administered intraperitoneally 20 min before three consequent daily 120-min IVSA sessions under a fixed ratio FR1, which significantly reduced the number of the active lever-pressing, the number of infusions, and the cannabinoid intake. Pretreatment with JMV2959 suggested reduction of the WIN55,212-2-seeking/relapse-like behavior tested in rats on the twelfth day of the forced abstinence period. On the contrary, pretreatment with ghrelin significantly increased the cannabinoid IVSA as well as enhanced the relapse-like behavior. Co-administration of ghrelin with JMV2959 abolished/reduced the significant efficacy of the GHS-R1A antagonist in the cannabinoid IVSA. Pretreatment with JMV2959 significantly and dose-dependently reduced the manifestation of THC-induced CPP. The THC-CPP development was reduced after the simultaneous administration of JMV2959 with THC during conditioning. JMV2959 also significantly reduced the THC-induced behavioral stimulation in the LABORAS cage. Our findings suggest that GHS-R1A importantly participates in the rewarding/reinforcing effects of cannabinoids.

scholarly journals Cortistatin Is Not a Somatostatin Analogue but Stimulates Prolactin Release and Inhibits GH and ACTH in a Gender-Dependent Fashion: Potential Role of Ghrelin

Endocrinology ◽  
2011 ◽  
Vol 152 (12) ◽  
pp. 4800-4812 ◽  
Author(s):  
José Córdoba-Chacón ◽  
Manuel D. Gahete ◽  
Ana I. Pozo-Salas ◽  
Antonio J. Martínez-Fuentes ◽  
Luis de Lecea ◽  
...  
Keyword(s):  
Metabolic Phenotype ◽  
Somatostatin Analogue ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Ancestral Gene ◽  
Ghrelin Receptor ◽  
Physiological Relevance

Cortistatin (CST) and somatostatin (SST) evolve from a common ancestral gene and share remarkable structural, pharmacological, and functional homologies. Although CST has been considered as a natural SST-analogue acting through their shared receptors (SST receptors 1–5), emerging evidence indicates that these peptides might in fact exert unique roles via selective receptors [e.g. CST, not SST, binds ghrelin receptor growth hormone secretagogue receptor type 1a (GHS-R1a)]. To determine whether the role of endogenous CST is different from SST, we characterized the endocrine-metabolic phenotype of male/female CST null mice (cort−/−) at hypothalamic-pituitary-systemic (pancreas-stomach-adrenal-liver) levels. Also, CST effects on hormone expression/secretion were evaluated in primary pituitary cell cultures from male/female mice and female primates (baboons). Specifically, CST exerted an unexpected stimulatory role on prolactin (PRL) secretion, because both male/female cort−/− mice had reduced PRL levels, and CST treatment (in vivo and in vitro) increased PRL secretion, which could be blocked by a GHS-R1a antagonist in vitro and likely relates to the decreased success of female cort−/− in first-litter pup care at weaning. In contrast, CST inhibited GH and adrenocorticotropin-hormone axes in a gender-dependent fashion. In addition, a rise in acylated ghrelin levels was observed in female cort−/− mice, which were associated with an increase in stomach ghrelin/ghrelin O-acyl transferase expression. Finally, CST deficit uncovered a gender-dependent role of this peptide in the regulation of glucose-insulin homeostasis, because male, but not female, cort−/− mice developed insulin resistance. The fact that these actions are not mimicked by SST and are strongly gender dependent offers new grounds to investigate the hitherto underestimated physiological relevance of CST in the regulation of physiological/metabolic processes.

scholarly journals Ghrelin Amplifies Dopamine Signaling by Cross Talk Involving Formation of Growth Hormone Secretagogue Receptor/Dopamine Receptor Subtype 1 Heterodimers

2006 ◽  
Vol 20 (8) ◽  
pp. 1772-1785 ◽  
Author(s):  
Hong Jiang ◽  
Lorena Betancourt ◽  
Roy G. Smith
Keyword(s):  
Dopamine Receptor ◽  
Fluorescent Protein ◽  
Green Fluorescent Protein Fluorescence ◽  
Receptor Subtype ◽  
Protein Fluorescence ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Ghrelin Receptor ◽  
Dopamine Signaling

Abstract Our objective is to determine the neuromodulatory role of ghrelin in the brain. To identify neurons that express the ghrelin receptor [GH secretagogue receptor (GHS-R)], we generated GHS-R-IRES-tauGFP mice by gene targeting. Neurons expressing the GHS-R exhibit green fluorescence and are clearly evident in the hypothalamus, hippocampus, cortex, and midbrain. Using immunohistochemistry in combination with green fluorescent protein fluorescence, we identified neurons that coexpress the dopamine receptor subtype 1 (D1R) and GHS-R. The potential physiological relevance of coexpression of these two receptors and the direct effect of ghrelin on dopamine signaling was investigated in vitro. Activation of GHS-R by ghrelin amplifies dopamine/D1R-induced cAMP accumulation. Intriguingly, amplification involves a switch in G protein coupling of the GHS-R from Gα11/q to Gαi/o by a mechanism consistent with agonist-dependent formation of GHS-R/D1R heterodimers. Most importantly, these results indicate that ghrelin has the potential to amplify dopamine signaling selectively in neurons that coexpress D1R and GHS-R.

scholarly journals GHSR-D2R heteromerization modulates dopamine signaling through an effect on G protein conformation

2018 ◽  
Vol 115 (17) ◽  
pp. 4501-4506 ◽  
Author(s):  
Marjorie Damian ◽  
Véronique Pons ◽  
Pedro Renault ◽  
Céline M’Kadmi ◽  
Bartholomé Delort ◽  
...  
Keyword(s):  
G Protein ◽  
Molecular Processes ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Α Subunit ◽  
Protein Activation ◽  
Gi Protein ◽  
Dopamine Signaling ◽  
Lipid Environment ◽  
Tetrameric Complex

The growth hormone secretagogue receptor (GHSR) and dopamine receptor (D2R) have been shown to oligomerize in hypothalamic neurons with a significant effect on dopamine signaling, but the molecular processes underlying this effect are still obscure. We used here the purified GHSR and D2R to establish that these two receptors assemble in a lipid environment as a tetrameric complex composed of two each of the receptors. This complex further recruits G proteins to give rise to an assembly with only two G protein trimers bound to a receptor tetramer. We further demonstrate that receptor heteromerization directly impacts on dopamine-mediated Gi protein activation by modulating the conformation of its α-subunit. Indeed, association to the purified GHSR:D2R heteromer triggers a different active conformation of Gαi that is linked to a higher rate of GTP binding and a faster dissociation from the heteromeric receptor. This is an additional mechanism to expand the repertoire of GPCR signaling modulation that could have implications for the control of dopamine signaling in normal and physiopathological conditions.

scholarly journals Function-related conformational dynamics of G protein–coupled receptors revealed by NMR

2019 ◽  
Vol 11 (3) ◽  
pp. 409-418 ◽  
Author(s):  
Takumi Ueda ◽  
Yutaka Kofuku ◽  
Junya Okude ◽  
Shunsuke Imai ◽  
Yutaro Shiraishi ◽  
...  
Keyword(s):  
G Protein ◽  
Conformational Dynamics ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled

Activation and conformational dynamics of a class B G-protein-coupled glucagon receptor

2016 ◽  
Vol 18 (18) ◽  
pp. 12642-12650 ◽  
Author(s):  
Yang Li ◽  
Jixue Sun ◽  
Dongmei Li ◽  
Jianping Lin
Keyword(s):  
Hydrogen Bonds ◽  
G Protein ◽  
Conformational Dynamics ◽  
Glucagon Receptor ◽  
Class B ◽  
G Protein Coupled

The binding of the agonist glucagon would induce the conformational dynamics and activation of the GCGR. The activation led to the outward movement of helix VII and breaking of two hydrogen bonds.

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