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Chandler B, Todd L, Smith SO. Magic angle spinning NMR of G protein-coupled receptors. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 128:25-43. [PMID: 35282868 PMCID: PMC10718405 DOI: 10.1016/j.pnmrs.2021.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 06/14/2023]
Abstract
G protein-coupled receptors (GPCRs) have a simple seven transmembrane helix architecture which has evolved to recognize a diverse number of chemical signals. The more than 800 GPCRs encoded in the human genome function as receptors for vision, smell and taste, and mediate key physiological processes. Consequently, these receptors are a major target for pharmaceuticals. Protein crystallography and electron cryo-microscopy have provided high resolution structures of many GPCRs in both active and inactive conformations. However, these structures have not sparked a surge in rational drug design, in part because GPCRs are inherently dynamic and the structural changes induced by ligand or drug binding to stabilize inactive or active conformations are often subtle rearrangements in packing or hydrogen-bonding interactions. NMR spectroscopy provides a sensitive probe of local structure and dynamics at specific sites within these receptors as well as global changes in receptor structure and dynamics. These methods can also capture intermediate states and conformations with low populations that provide insights into the activation pathways. We review the use of solid-state magic angle spinning NMR to address the structure and activation mechanisms of GPCRs. The focus is on the large and diverse class A family of receptors. We highlight three specific class A GPCRs in order to illustrate how solid-state, as well as solution-state, NMR spectroscopy can answer questions in the field involving how different GPCR classes and subfamilies are activated by their associated ligands, and how small molecule drugs can modulate GPCR activation.
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Affiliation(s)
- Bianca Chandler
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
| | - Lauren Todd
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
| | - Steven O Smith
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, United States.
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Biophysical and functional characterization of the human TAS1R2 sweet taste receptor overexpressed in a HEK293S inducible cell line. Sci Rep 2021; 11:22238. [PMID: 34782704 PMCID: PMC8593021 DOI: 10.1038/s41598-021-01731-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 11/01/2021] [Indexed: 01/02/2023] Open
Abstract
Sweet taste perception is mediated by a heterodimeric receptor formed by the assembly of the TAS1R2 and TAS1R3 subunits. TAS1R2 and TAS1R3 are class C G-protein-coupled receptors whose members share a common topology, including a large extracellular N-terminal domain (NTD) linked to a seven transmembrane domain (TMD) by a cysteine-rich domain. TAS1R2-NTD contains the primary binding site for sweet compounds, including natural sugars and high-potency sweeteners, whereas the TAS1R2-TMD has been shown to bind a limited number of sweet tasting compounds. To understand the molecular mechanisms governing receptor–ligand interactions, we overexpressed the human TAS1R2 (hTAS1R2) in a stable tetracycline-inducible HEK293S cell line and purified the detergent-solubilized receptor. Circular dichroism spectroscopic studies revealed that hTAS1R2 was properly folded with evidence of secondary structures. Using size exclusion chromatography coupled to light scattering, we found that the hTAS1R2 subunit is a dimer. Ligand binding properties were quantified by intrinsic tryptophan fluorescence. Due to technical limitations, natural sugars have not been tested. However, we showed that hTAS1R2 is capable of binding high potency sweeteners with Kd values that are in agreement with physiological detection. This study offers a new experimental strategy to identify new sweeteners or taste modulators that act on the hTAS1R2 and is a prerequisite for structural query and biophysical studies.
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Shen M, Li Y, Wang Y, Shao J, Zhang F, Yin G, Chen A, Zhang Z, Zheng S. N 6-methyladenosine modification regulates ferroptosis through autophagy signaling pathway in hepatic stellate cells. Redox Biol 2021; 47:102151. [PMID: 34607160 PMCID: PMC8495178 DOI: 10.1016/j.redox.2021.102151] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 09/24/2021] [Indexed: 01/18/2023] Open
Abstract
Ferroptosis is a recently identified non-apoptotic form of cell death characterized by iron-dependent lipid peroxidation. However, the underlying exact mechanisms remain poorly understood. Here, we report that the total levels of N6-methyladenosine (m6A) modification are evidently increased upon exposure to ferroptosis-inducing compounds due to the upregulation of methylase METTL4 and the downregulation of demethylase FTO. Interestingly, RNA-seq shows that m6A modification appears to trigger autophagy activation by stabilizing BECN1 mRNA, which may be the potential mechanism for m6A modification-enhanced HSC ferroptosis. Importantly, YTHDF1 is identified as a key m6A reader protein for BECN1 mRNA stability, and knockdown of YTHDF1 could prevent BECN1 plasmid-induced HSC ferroptosis. Noteworthy, YTHDF1 promotes BECN1 mRNA stability and autophagy activation via recognizing the m6A binding site within BECN1 coding regions. In mice, erastin treatment alleviates liver fibrosis by inducing HSC ferroptosis. HSC-specific inhibition of m6A modification could impair erastin-induced HSC ferroptosis in murine liver fibrosis. Moreover, we retrospectively analyzed the effect of sorafenib on HSC ferroptosis and m6A modification in advanced fibrotic patients with hepatocellular carcinoma (HCC) receiving sorafenib monotherapy. Attractively, the m6A modification upregulation, autophagy activation, and ferroptosis induction occur in human HSCs. Overall, these findings reveal novel signaling pathways and molecular mechanisms of ferroptosis, and also identify m6A modification-dependent ferroptosis as a potential target for the treatment of liver fibrosis.
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Affiliation(s)
- Min Shen
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yujia Li
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yingqian Wang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Jiangjuan Shao
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Feng Zhang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China; Jiangsu Key Laboratory of Therapeutic Material of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Guoping Yin
- Department of Anesthesiology, Nanjing Hospital Affiliated to Nanjing University of Chinese Medicine, Nanjing, China
| | - Anping Chen
- Department of Pathology, School of Medicine, Saint Louis University, St Louis. MO, 63104, USA
| | - Zili Zhang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China; Jiangsu Key Laboratory of Therapeutic Material of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
| | - Shizhong Zheng
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China; Jiangsu Key Laboratory of Therapeutic Material of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
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Li R, Wang F, Wei J, Lin Y, Tang G, Rao L, Ma L, Xu Q, Wu J, Lv Q, Zhou R, Lei H, Zhao X, Yao D, Xiao B, Huang H, Zhang J, Mo B. The Role of Macrophage Migration Inhibitory Factor (MIF) in Asthmatic Airway Remodeling. ALLERGY, ASTHMA & IMMUNOLOGY RESEARCH 2021; 13:88-105. [PMID: 33191679 PMCID: PMC7680835 DOI: 10.4168/aair.2021.13.1.88] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/10/2020] [Accepted: 05/17/2020] [Indexed: 12/23/2022]
Abstract
Purpose Recent studies have demonstrated that macrophage migration inhibitory factor (MIF) is of importance in asthmatic inflammation. The role of MIF in modulating airway remodeling has not yet been thoroughly elucidated to date. In the present study, we hypothesized that MIF promoted airway remodeling by intensifying airway smooth muscle cell (ASMC) autophagy and explored the specific mechanisms. Methods MIF knockdown in the lung tissues of C57BL/6 mice was conducted by instilling intratracheally adeno-associated virus (AAV) vectors (MIF-mutant AAV9) into mouse lung tissues. Mice genetically deficient in the autophagy marker ATG5 (ATG5+/−) was used to detect the role of autophagy in ovalbumin (OVA)-asthmatic murine models. Moreover, to block the expression of MIF and CD74 in vitro models, inhibitors, antibodies and lentivirus transfection techniques were employed. Results First, MIF knockdown in the lung tissues of mice showed markedly reduced airway remodeling in OVA murine mice models. Secondly, ASMC autophagy was increased in the OVA-challenged models. Mice genetically deficient in the autophagy marker ATG5 (ATG5+/−) that were primed and challenged with OVA showed lower airway remodeling than genetically wild-type asthmatic mice. Thirdly, MIF can induce ASMC autophagy in vitro. Moreover, the cellular source of MIF which promoted ASMC autophagy was macrophages. Finally, MIF promoted ASMC autophagy in a CD74-dependent manner. Conclusions MIF can increase asthmatic airway remodeling by enhancing ASMC autophagy. Macrophage-derived MIF can promote ASMC autophagy by targeting CD74.
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Affiliation(s)
- Ruyi Li
- Department of Respiratory and Critical Care Medicine, Key Laboratory of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha, China
| | - Feiyun Wang
- Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jianghong Wei
- Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Yun Lin
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Guofang Tang
- Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Lizong Rao
- Laboratory of Pulmonary Diseases, Guilin Medical University, Guilin, China
| | - Libing Ma
- Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Qing Xu
- Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Jingjie Wu
- Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Qian Lv
- Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Rui Zhou
- Department of Respiratory and Critical Care Medicine, The Second Xiangya Hospital, Changsha, China
| | - Huiren Lei
- Laboratory of Pulmonary Diseases, Guilin Medical University, Guilin, China
| | - Xueqiang Zhao
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Dong Yao
- Laboratory of Pulmonary Diseases, Guilin Medical University, Guilin, China
| | - Bo Xiao
- Laboratory of Pulmonary Diseases, Guilin Medical University, Guilin, China
| | - Haiming Huang
- Laboratory of Pulmonary Diseases, Guilin Medical University, Guilin, China
| | - Jiange Zhang
- Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Biwen Mo
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital of Guilin Medical University, Guilin, China.
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Zhang Z, Guo M, Li Y, Shen M, Kong D, Shao J, Ding H, Tan S, Chen A, Zhang F, Zheng S. RNA-binding protein ZFP36/TTP protects against ferroptosis by regulating autophagy signaling pathway in hepatic stellate cells. Autophagy 2019; 16:1482-1505. [PMID: 31679460 DOI: 10.1080/15548627.2019.1687985] [Citation(s) in RCA: 259] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Ferroptosis is a recently discovered form of programmed cell death, but its regulatory mechanisms remain poorly understood. Here, we show that the RNA-binding protein ZFP36/TTP (ZFP36 ring finger protein) plays a crucial role in regulating ferroptosis in hepatic stellate cells (HSCs). Upon exposure to ferroptosis-inducing compounds, the ubiquitin ligase FBXW7/CDC4 (F-box and WD repeat domain containing 7) decreased ZFP36 protein expression by recognizing SFSGLPS motif. FBXW7 plasmid contributed to classical ferroptotic events, whereas ZFP36 plasmid impaired FBXW7 plasmid-induced HSC ferroptosis. Interestingly, ZFP36 plasmid inhibited macroautophagy/autophagy activation by destabilizing ATG16L1 (autophagy related 16 like 1) mRNA. ATG16L1 plasmid eliminated the inhibitory action of ZFP36 plasmid on ferroptosis, and FBXW7 plasmid enhanced the effect of ATG16L1 plasmid on autophagy. Importantly, ZFP36 plasmid promoted ATG16L1 mRNA decay via binding to the AU-rich elements (AREs) within the 3'-untranslated region. The internal mutation of the ARE region abrogated the ZFP36-mediated ATG16L1 mRNA instability, and prevented ZFP36 plasmid-mediated ferroptosis resistance. In mice, treatment with erastin and sorafenib alleviated murine liver fibrosis by inducing HSC ferroptosis. HSC-specific overexpression of Zfp36 impaired erastin- or sorafenib-induced HSC ferroptosis. Noteworthy, we analyzed the effect of sorafenib on HSC ferroptosis in fibrotic patients with hepatocellular carcinoma receiving sorafenib monotherapy. Attractively, sorafenib monotherapy led to ZFP36 downregulation, ferritinophagy activation, and ferroptosis induction in human HSCs. Overall, these results revealed novel molecular mechanisms and signaling pathways of ferroptosis, and also identified ZFP36-autophagy-dependent ferroptosis as a potential target for the treatment of liver fibrosis. ABBREVIATIONS ARE: AU-rich elements; ATG: autophagy related; BECN1: beclin 1; CHX: cycloheximide; COL1A1: collagen type I alpha 1 chain; ELAVL1/HuR: ELAV like RNA binding protein 1; FBXW7/CDC4: F-box and WD repeat domain containing 7; FN1: fibronectin 1; FTH1: ferritin heavy chain 1; GPX4/PHGPx: glutathione peroxidase 4; GSH: glutathione; HCC: hepatocellular carcinoma; HSC: hepatic stellate cell; LSEC: liver sinusoidal endothelial cell; MAP1LC3A: microtubule associated protein 1 light chain 3 alpha; MDA: malondialdehyde; NCOA4: nuclear receptor coactivator 4; PTGS2/COX2: prostaglandin-endoperoxide synthase 2; RBP: RNA-binding protein; ROS: reactive oxygen species; SLC7A11/xCT: solute carrier family 7 member 11; SQSTM1/p62: sequestosome 1; TNF: tumor necrosis factor; TP53/p53: tumor protein p53; UTR: untranslated region; ZFP36/TTP: ZFP36 ring finger protein.
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Affiliation(s)
- Zili Zhang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine , Nanjing, China
| | - Mei Guo
- Department of Pathogenic biology and Immunology, Medical School, Southeast University , Nanjing, China
| | - Yujia Li
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine , Nanjing, China
| | - Min Shen
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine , Nanjing, China
| | - Desong Kong
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine , Nanjing, China
| | - Jiangjuan Shao
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine , Nanjing, China
| | - Hai Ding
- Department of Integrated TCM and Western Medicine, Nanjing Hospital Affiliated to Nanjing University of Chinese Medicine , Nanjing, China
| | - Shanzhong Tan
- Department of Integrated TCM and Western Medicine, Nanjing Hospital Affiliated to Nanjing University of Chinese Medicine , Nanjing, China
| | - Anping Chen
- Department of Pathology, School of Medicine, Saint Louis University , St Louis, USA
| | - Feng Zhang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine , Nanjing, China.,Jiangsu Key Laboratory of Therapeutic Material of Chinese Medicine, Nanjing University of Chinese Medicine , Nanjing, China
| | - Shizhong Zheng
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine , Nanjing, China.,Jiangsu Key Laboratory of Therapeutic Material of Chinese Medicine, Nanjing University of Chinese Medicine , Nanjing, China
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Abstract
AbstractIncreasing evidence suggests that most proteins occur and function in complexes rather than as isolated entities when embedded in cellular membranes. Nuclear magnetic resonance (NMR) provides increasing possibilities to study structure, dynamics and assembly of such systems. In our review, we discuss recent methodological progress to study membrane–protein complexes (MPCs) by NMR, starting with expression, isotope-labeling and reconstitution protocols. We review approaches to deal with spectral complexity and limited spectral spectroscopic sensitivity that are usually encountered in NMR-based studies of MPCs. We highlight NMR applications in various classes of MPCs, including G-protein-coupled receptors, ion channels and retinal proteins and extend our discussion to protein–protein complexes that span entire cellular compartments or orchestrate processes such as protein transport across or within membranes. These examples demonstrate the growing potential of NMR-based studies of MPCs to provide critical insight into the energetics of protein–ligand and protein–protein interactions that underlie essential biological functions in cellular membranes.
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Isotope Labeling of Eukaryotic Membrane Proteins in Yeast for Solid-State NMR. Methods Enzymol 2015; 565:193-212. [DOI: 10.1016/bs.mie.2015.05.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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