Structural basis of human ghrelin receptor signaling by ghrelin and the synthetic agonist ibutamoren

Liu, Heng; Sun, Dapeng; Myasnikov, Alexander; Damian, Marjorie; Banères, Jean-Louis; Sun, Ji; Zhang, Cheng

doi:10.1038/s41467-021-26735-5

Cited by 35 publications

(32 citation statements)

References 56 publications

(58 reference statements)

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“…G i -coupling was almost identical among in the three complex structures ( Fig. 4a ), where G i protein was anchored by the α5 helix of G i subunit, thereby fitting to the cytoplasmic cavity formed by TMs 2, 3 and 5-7 as well as ICLs 2 and 3, a phenomenon widely observed in other G i -coupled structures such as GHSR 36 , formyl peptide receptor 2 (FPR2) 37 and CCR1 28 ( Fig. 4a-b ).…”

Section: Resultsmentioning

confidence: 57%

“…Unlike its class B1 counterparts that have large extracellular domains, class A GPCRs usually adopt extended loop conformations during their insertion into the orthosteric pocket by the peptide N terminus [ e . g ., DAMGO 44 , C-C chemokine ligand 15 (CCL15) 28 , C-X-C motif chemokine ligand 8 (CXCL8) 45 , Aβ 42 46 , N -formyl humanin 46 and ghrelin 36 ], the peptide C terminus [ e . g ., angiotensin II 47,48 , bradykinin 27 , cholecystokinin-8 (CCK-8) 49 , Des-Arg 10 -kallidin 27 , gastrin-17 25 , IMV449 50 , neuromedin U 51 and neuromedin S 51 ] or the peptide middle region [ e .…”

Section: Resultsmentioning

confidence: 99%

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A unique peptide recognition mechanism by the human relaxin family peptide receptor 4 (RXFP4)

Chen

Zhou

Wang

et al. 2022

Preprint

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Members of the insulin superfamily regulate a variety of biological processes through two types of target-specific but structurally conserved peptides, insulin/insulin-like growth factors and relaxin/insulin-like peptides. The latter bind to the human relaxin family peptide receptors (RXFPs), which are class A G protein-coupled receptors (GPCRs), to exert pleiotropic actions. Here, we report three cryo-electron microscopy structures of RXFP4—Gi protein complexes in the presence of the endogenous ligand insulin-like peptide 5 (INSL5) or one of the two small molecule agonists, compound 4 and DC591053, both were discovered through medicinal chemistry efforts. The B chain of INSL5 adopts a single α-helix that penetrates into the orthostatic pocket, while the A chain sits above the orthosteric pocket to interact with the extracellular surface of RXFP4, revealing a unique peptide-binding mode previously unknown. Together with mutagenesis and functional analyses, the key determinants responsible for the peptidomimetic agonism and subtype selectivity were identified. DC591053 selectively mimicked the action of INSL5 at RXFP4 whereas compound 4 activated both RXFP3 and RXFP4. Comparison of peptide binding modes within the insulin superfamily displayed diverse interaction mechanisms distinct to each type of the peptides. Our findings not only provide valuable insights into ligand recognition and subtype selectivity among class A GPCRs, but also expand the knowledge of signaling mechanisms in the insulin superfamily.

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Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 99%

A unique peptide recognition mechanism by the human relaxin family peptide receptor 4 (RXFP4)

Chen

Zhou

Wang

et al. 2022

Preprint

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“…[42] Mutating F286 and F290 to alanine or polar and charged amino acids displays dramatically diminished receptor activity. [41][42][43] In conclusion, GHS-R1a is capable of binding different ligands in a variety of ways, depending on the selectivity…”

Section: Journal Of Translational Internal Medicine / Aopmentioning

confidence: 95%

Binding domain characterization of growth hormone secretagogue receptor

Sun

Kennedy

et al. 2022

Journal of Translational Internal Medicine

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Background and Objectives Activation of ghrelin receptor growth hormone secretagogue receptor (GHS-R) by endogenous or synthetic ligands amplifies pulsatile release of growth hormone (GH) and enhances food intake, very relevant to development and growth. GHS-R is a G-protein coupled receptor that has great druggable potential. Understanding the precise ligand and receptor interactions is crucial to advance the application of GHS-R. Materials and Methods We used radiolabeled ligand-binding assay and growth hormone release assay to assess the binding and functional characteristics of GHS-R to synthetic agonists MK-0677 and GHS-25, as well as to endogenous peptide ligand ghrelin. We analyzed the ligand-dependent activity of GHS-R by measuring aequorin-based [Ca++]i responses. To define a ligand-binding pocket of GHS-R, we generated a series of human/puffer fish GHS-R chimeras by domain swapping, as well as a series of mutants by site-directed mutagenesis. Results We found that the synthetic ligands have high binding affinity to GHS-R in the in vitro competitive binding assay. Remarkably, the in vivo GH secretagogue activity is higher with the synthetic agonists MK-0677 and GHS-25 than that of ghrelin. Importantly, the activity was completely abolished in GHS-R knockout mice. In GHS-R chimera analysis, we identified the C-terminal region, particularly the transmembrane domain 6 (TM6), to be critical for the ligand-dependent activity. Our site-directed mutagenesis study further revealed that amino acid residues D99 and W276 in GHS-R are essential for ligand binding. Interestingly, critical residues distinctively interact with different ligands, MK-0677 activation depends on E124, while ghrelin and GHS-25 preferentially interact with F279. Conclusion The ligand-binding pocket of human GHS-R is mainly defined by interactive residues in TM6 and the adjacent region of the receptor. This novel finding in GHS-R binding domains advances the structural/ functional understanding of GHS-R, which will help to select/design better GHS-R agonists/ antagonists for future therapeutic applications.

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“…C) Compound 3 is in the binding pocket. Adapted from ref ( 18 ), which was published under a Creative Commons Attribution 4.0 International (CC BY 4.0) License.…”

Section: Structure Of Ghs-r1amentioning

confidence: 99%

Advances in the Development of Nonpeptide Small Molecules Targeting Ghrelin Receptor

et al. 2022

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Ghrelin is an octanoylated peptide acting by the activation of the growth hormone secretagogue receptor, namely, GHS-R1a. The involvement of ghrelin in several physiological processes, including stimulation of food intake, gastric emptying, body energy balance, glucose homeostasis, reduction of insulin secretion, and lipogenesis validates the considerable interest in GHS-R1a as a promising target for the treatment of numerous disorders. Over the years, several GHS-R1a ligands have been identified and some of them have been extensively studied in clinical trials. The recently resolved structures of GHS-R1a bound to ghrelin or potent ligands have provided useful information for the design of new GHS-R1a drugs. This perspective is focused on the development of recent nonpeptide small molecules acting as GHS-R1a agonists, antagonists, and inverse agonists, bearing classical or new molecular scaffolds, as well as on radiolabeled GHS-R1a ligands developed for imaging. Moreover, the pharmacological effects of the most studied ligands have been discussed.

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Structural basis of human ghrelin receptor signaling by ghrelin and the synthetic agonist ibutamoren

Cited by 35 publications

References 56 publications

A unique peptide recognition mechanism by the human relaxin family peptide receptor 4 (RXFP4)

A unique peptide recognition mechanism by the human relaxin family peptide receptor 4 (RXFP4)

Binding domain characterization of growth hormone secretagogue receptor

Advances in the Development of Nonpeptide Small Molecules Targeting Ghrelin Receptor

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