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Cong Z, Zhao F, Li Y, Luo G, Mai Y, Chen X, Chen Y, Lin S, Cai X, Zhou Q, Yang D, Wang MW. Molecular features of the ligand-free GLP-1R, GCGR and GIPR in complex with G s proteins. Cell Discov 2024; 10:18. [PMID: 38346960 PMCID: PMC10861504 DOI: 10.1038/s41421-024-00649-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 01/15/2024] [Indexed: 02/15/2024] Open
Abstract
Class B1 G protein-coupled receptors (GPCRs) are important regulators of many physiological functions such as glucose homeostasis, which is mainly mediated by three peptide hormones, i.e., glucagon-like peptide-1 (GLP-1), glucagon (GCG), and glucose-dependent insulinotropic polypeptide (GIP). They trigger a cascade of signaling events leading to the formation of an active agonist-receptor-G protein complex. However, intracellular signal transducers can also activate the receptor independent of extracellular stimuli, suggesting an intrinsic role of G proteins in this process. Here, we report cryo-electron microscopy structures of the human GLP-1 receptor (GLP-1R), GCG receptor (GCGR), and GIP receptor (GIPR) in complex with Gs proteins without the presence of cognate ligands. These ligand-free complexes share a similar intracellular architecture to those bound by endogenous peptides, in which, the Gs protein alone directly opens the intracellular binding cavity and rewires the extracellular orthosteric pocket to stabilize the receptor in a state unseen before. While the peptide-binding site is partially occupied by the inward folded transmembrane helix 6 (TM6)-extracellular loop 3 (ECL3) juncture of GIPR or a segment of GCGR ECL2, the extracellular portion of GLP-1R adopts a conformation close to the active state. Our findings offer valuable insights into the distinct activation mechanisms of these three important receptors. It is possible that in the absence of a ligand, the intracellular half of transmembrane domain is mobilized with the help of Gs protein, which in turn rearranges the extracellular half to form a transitional conformation, facilitating the entry of the peptide N-terminus.
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Affiliation(s)
- Zhaotong Cong
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Fenghui Zhao
- State Key Laboratory of Chemical Biology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Yang Li
- Shanghai Institute of Infectious Disease and Biosecurity, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Gan Luo
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yiting Mai
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
| | - Xianyue Chen
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
| | - Yanyan Chen
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
| | - Shi Lin
- Research Center for Deepsea Bioresources, Sanya, Hainan, China
| | - Xiaoqing Cai
- State Key Laboratory of Chemical Biology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Qingtong Zhou
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
- Research Center for Deepsea Bioresources, Sanya, Hainan, China.
| | - Dehua Yang
- State Key Laboratory of Chemical Biology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- Research Center for Deepsea Bioresources, Sanya, Hainan, China.
| | - Ming-Wei Wang
- Research Center for Deepsea Bioresources, Sanya, Hainan, China.
- Department of Chemistry, School of Science, The University of Tokyo, Tokyo, Japan.
- School of Pharmacy, Hainan Medical University, Haikou, Hainan, China.
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Shi Y, Chen Y, Deng L, Du K, Lu S, Chen T. Structural Understanding of Peptide-Bound G Protein-Coupled Receptors: Peptide-Target Interactions. J Med Chem 2023; 66:1083-1111. [PMID: 36625741 DOI: 10.1021/acs.jmedchem.2c01309] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The activation of G protein-coupled receptors (GPCRs) is triggered by ligand binding to their orthosteric sites, which induces ligand-specific conformational changes. Agonists and antagonists bound to GPCR orthosteric sites provide detailed information on ligand-binding modes. Among these, peptide ligands play an instrumental role in GPCR pharmacology and have attracted increased attention as therapeutic drugs. The recent breakthrough in GPCR structural biology has resulted in the remarkable availability of peptide-bound GPCR complexes. Despite the several structural similarities shared by these receptors, they exhibit distinct features in terms of peptide recognition and receptor activation. From this perspective, we have summarized the current status of peptide-bound GPCR structural complexes, largely focusing on the interactions between the receptor and its peptide ligand at the orthosteric site. In-depth structural investigations have yielded valuable insights into the molecular mechanisms underlying peptide recognition. This study would contribute to the discovery of GPCR peptide drugs with improved therapeutic effects.
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Affiliation(s)
- Yuxin Shi
- School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing 312000, China.,Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Yi Chen
- Department of Ultrasound Interventional, Eastern Hepatobiliary Surgery Hospital, Navy Medical University, Shanghai 200433, China
| | - Liping Deng
- School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing 312000, China
| | - Kui Du
- School of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing 312000, China
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China.,Institute of Energy Metabolism and Health, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.,College of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750004, China
| | - Ting Chen
- Department of Cardiology, Changzheng Hospital, Naval Medical University, Shanghai 200003, China
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Abstract
Heliorhodopsin (HeR), a recently discovered new rhodopsin family, has an inverted membrane topology compared to animal and microbial rhodopsins, and no ion-transport activity. The slow photocycle of HeRs suggests a light-sensor function, although the function remains unknown. HeRs exhibit no specific binding of monovalent cations or anions. Despite this, ATR-FTIR spectroscopy in the present study demonstrates binding of Zn2+ to HeR from Thermoplasmatales archaeon (TaHeR). The biding of Zn2+ to 0.2 mM Kd is accompanied by helical structural perturbations without altering its color. Even though ion-specific FTIR spectra were observed for many divalent cations, only helical structural perturbations were observed for Zn2+-binding. Similar results were obtained for HeR 48C12. These findings suggest a possible modification of HeR function by Zn2+.
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Affiliation(s)
- Masanori Hashimoto
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Yuji Furutani
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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Newstead S, Barr F. Molecular basis for KDEL-mediated retrieval of escaped ER-resident proteins - SWEET talking the COPs. J Cell Sci 2020; 133:133/19/jcs250100. [PMID: 33037041 PMCID: PMC7561476 DOI: 10.1242/jcs.250100] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/30/2020] [Indexed: 12/11/2022] Open
Abstract
Protein localisation in the cell is controlled through the function of trafficking receptors, which recognise specific signal sequences and direct cargo proteins to different locations. The KDEL receptor (KDELR) was one of the first intracellular trafficking receptors identified and plays an essential role in maintaining the integrity of the early secretory pathway. The receptor recognises variants of a canonical C-terminal Lys-Asp-Glu-Leu (KDEL) signal sequence on ER-resident proteins when these escape to the Golgi, and targets these proteins to COPI- coated vesicles for retrograde transport back to the ER. The empty receptor is then recycled from the ER back to the Golgi by COPII-coated vesicles. Crystal structures of the KDELR show that it is structurally related to the PQ-loop family of transporters that are found in both pro- and eukaryotes, and shuttle sugars, amino acids and vitamins across cellular membranes. Furthermore, analogous to PQ-loop transporters, the KDELR undergoes a pH-dependent and ligand-regulated conformational cycle. Here, we propose that the striking structural similarity between the KDELR and PQ-loop transporters reveals a connection between transport and trafficking in the cell, with important implications for understanding trafficking receptor evolution and function. Summary: The structure of the KDEL receptor gives new insights into the close connection between trafficking and transport in the cell.
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Affiliation(s)
- Simon Newstead
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford OX1 3QU, UK
| | - Francis Barr
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford OX1 3QU, UK
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Doi T, Kikuta K, Tani K. Characterization of Critical Residues in the Extracellular and Transmembrane Domains of the Endothelin Type B Receptor for Propagation of the Endothelin-1 Signal. Biochemistry 2020; 59:1718-1727. [PMID: 32343134 DOI: 10.1021/acs.biochem.0c00158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have previously reported the crystal structures of endothelin-1 (ET-1)-bound, ligand-free, and antagonist bosentan-bound forms of the thermostabilized ET type B receptor (ETB). Although other agonist-bound structures of ETB have been determined, the interactions for high-affinity binding and ETB receptor activation, as well as the roles of rearrangement of the hydrogen-bond network surrounding the ligand in G protein activation, remain elusive. ET-1, a 21-amino acid residue peptide, plays fundamental roles in basal vascular tone, sodium balance, cell proliferation, and stress-responsive regulation. We studied the interactions between the ET-1(8-21) peptide and ETB in the ligand binding and activation of ETB using a series of Ala-substituted ET-1(8-21) analogues and the mutated ETB. We found that while D8, L17, D18, I20, and W21 were responsible for high-affinity binding and potent G protein activation, Y13 and F14 in the helical region of ET-1 are prerequisites for the full activation of ETB via interactions near the extracellular side. Furthermore, we introduced the mutation into the residues around the ET-1 binding pocket of ETB. The results showed that while S1843.35, W3366.48, N3787.45, and S3797.46 in a conserved polar network are required for full activation, N1191.50, D1472.50, and N3827.49 are essential for G protein activation via direct interactions after rearrangement upon ET-1 binding. These results demonstrate that both interactions near the extracellular side and within the transmembrane helices with ET-1 play crucial roles in the full activation of the ETB receptor.
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Affiliation(s)
- Tomoko Doi
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Kohei Kikuta
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Kazutoshi Tani
- Graduate School of Medicine, Mie University, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
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Cai L, Li Q, Deng Y, Liu X, Du W, Jiang X. Construction and expression of recombinant uricase‑expressing genetically engineered bacteria and its application in rat model of hyperuricemia. Int J Mol Med 2020; 45:1488-1500. [PMID: 32323736 PMCID: PMC7138262 DOI: 10.3892/ijmm.2020.4512] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/28/2020] [Indexed: 12/18/2022] Open
Abstract
At present, the treatment of hyperuricemia is designed primarily to decrease the production of uric acid using xanthine oxidase inhibitors; however, the therapeutic effect is not satisfactory. Therefore, the key to the successful treatment of hyperuricemia is to increase the excretion of uric acid. The aim of present study was to construct uricase-expressing genetically engineered bacteria and analyze the effects of these engineered bacteria on the lowering of uric acid levels in a rat model of hyperuricemia. The uricase expression vector was constructed by gene recombination technology and transfected into Escherichia coli. The expression and activity of uricase were analyzed by SDS-PAGE analysis and Bradford assay. The water consumption, food intake, body weight, eosinophil count and intestinal histology, in addition to the levels of serum uric acid (SUA) and allantoin in the feces of the rats, were assessed. The intestinal contents of the rats were analyzed by 16S rDNA sequencing technology. The results demonstrated that uricase-expressing genetically engineered bacteria secreted active uricase. All rats exhibited a natural growth trend during the entire experiment, and the SUA of hyperuricemic rats treated with uricase-expressing engineered bacteria was significantly decreased. In conclusion, these results indicate that uricase secreted by recombinant uricase-expressing genetically engineered bacteria served an important role in decreasing SUA levels in a rat model of hyperuricemia.
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Affiliation(s)
- Liming Cai
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Qin Li
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Yongbing Deng
- Department of Neurosurgery, Chongqing Emergency Medical Center, Chongqing 400014, P.R. China
| | - Xianjun Liu
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Weihong Du
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Xue Jiang
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, P.R. China
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Sutkeviciute I, Clark LJ, White AD, Gardella TJ, Vilardaga JP. PTH/PTHrP Receptor Signaling, Allostery, and Structures. Trends Endocrinol Metab 2019; 30:860-874. [PMID: 31699241 PMCID: PMC6857722 DOI: 10.1016/j.tem.2019.07.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/09/2019] [Accepted: 07/12/2019] [Indexed: 02/08/2023]
Abstract
The parathyroid hormone (PTH) type 1 receptor (PTHR) is the canonical G protein-coupled receptor (GPCR) for PTH and PTH-related protein (PTHrP) and the key regulator of calcium homeostasis and bone turnover. PTHR function is critical for human health to maintain homeostatic control of ionized serum Ca2+ levels and has several unusual signaling features, such as endosomal cAMP signaling, that are well-studied but not structurally understood. In this review, we discuss how recently solved high resolution near-atomic structures of hormone-bound PTHR in its inactive and active signaling states and discovery of extracellular Ca2+ allosterism shed light on the structural basis for PTHR signaling and function.
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Affiliation(s)
- Ieva Sutkeviciute
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Lisa J Clark
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Graduate Program in Molecular Biophysics and Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Alex D White
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Graduate Program in Molecular Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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Endocytosis of G Protein-Coupled Receptors and Their Ligands: Is There a Role in Metal Trafficking? Cell Biochem Biophys 2018; 76:329-337. [PMID: 30022374 DOI: 10.1007/s12013-018-0850-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 07/03/2018] [Indexed: 12/22/2022]
Abstract
The prevalence of metal dysregulation in many neurodegenerative and neurocognitive disorders has compelled many studying such diseases to investigate the mechanisms underlying metal regulation in the central nervous system. Metal homoeostasis is often complex, with sophisticated, multilayered pathways in operation. G protein-coupled receptors are omnipresent on cell membranes and have intriguing mechanisms of endocytosis and trafficking that may be useful in metal homoeostasis. Indeed, many receptors and/or their cognate ligands are able to bind metals, and in many cases metals are considered to have neuromodulatory roles as a result of receptor binding. In this mini-review, we outline the structural and functional aspects of G protein-coupled receptors with a focus on the mechanisms leading to endocytosis and cellular trafficking. We further highlight how this may help in the trafficking of metal ions, notably copper.
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