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Yang LK, Hou ZS, Tao YX. Biased signaling in naturally occurring mutations of G protein-coupled receptors associated with diverse human diseases. Biochim Biophys Acta Mol Basis Dis 2021; 1867:165973. [PMID: 32949766 PMCID: PMC7722056 DOI: 10.1016/j.bbadis.2020.165973] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) play critical roles in transmitting a variety of extracellular signals into the cells and regulate diverse physiological functions. Naturally occurring mutations that result in dysfunctions of GPCRs have been known as the causes of numerous diseases. Significant progresses have been made in elucidating the pathophysiology of diseases caused by mutations. The multiple intracellular signaling pathways, such as G protein-dependent and β-arrestin-dependent signaling, in conjunction with recent advances on biased agonism, have broadened the view on the molecular mechanism of disease pathogenesis. This review aims to briefly discuss biased agonism of GPCRs (biased ligands and biased receptors), summarize the naturally occurring GPCR mutations that cause biased signaling, and propose the potential pathophysiological relevance of biased mutant GPCRs associated with various endocrine diseases.
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Affiliation(s)
- Li-Kun Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Zhi-Shuai Hou
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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152
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Oliveira de Souza C, Sun X, Oh D. Metabolic Functions of G Protein-Coupled Receptors and β-Arrestin-Mediated Signaling Pathways in the Pathophysiology of Type 2 Diabetes and Obesity. Front Endocrinol (Lausanne) 2021; 12:715877. [PMID: 34497585 PMCID: PMC8419444 DOI: 10.3389/fendo.2021.715877] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/29/2021] [Indexed: 12/17/2022] Open
Abstract
Seven transmembrane receptors (7TMRs), often termed G protein-coupled receptors (GPCRs), are the most common target of therapeutic drugs used today. Many studies suggest that distinct members of the GPCR superfamily represent potential targets for the treatment of various metabolic disorders including obesity and type 2 diabetes (T2D). GPCRs typically activate different classes of heterotrimeric G proteins, which can be subgrouped into four major functional types: Gαs, Gαi, Gαq/11, and G12/13, in response to agonist binding. Accumulating evidence suggests that GPCRs can also initiate β-arrestin-dependent, G protein-independent signaling. Thus, the physiological outcome of activating a certain GPCR in a particular tissue may also be modulated by β-arrestin-dependent, but G protein-independent signaling pathways. In this review, we will focus on the role of G protein- and β-arrestin-dependent signaling pathways in the development of obesity and T2D-related metabolic disorders.
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153
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Jiang Y, Lim J, Wu KC, Xu W, Suen JY, Fairlie DP. PAR2 induces ovarian cancer cell motility by merging three signalling pathways to transactivate EGFR. Br J Pharmacol 2020; 178:913-932. [PMID: 33226635 DOI: 10.1111/bph.15332] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 11/08/2020] [Accepted: 11/14/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE Specific cellular functions mediated by GPCRs are often associated with signalling through a particular G protein or β-arrestin. Here, we examine signalling through a GPCR, protease-activated receptor 2 (PAR2), in a high-grade serous ovarian cancer cell line (OV90). EXPERIMENTAL APPROACH Human ovarian cancer tissues (n = 1,200) and nine human ovarian cancer cell lines were assessed for PAR2 expression. PAR2 signalling mechanisms leading to cell migration and invasion were dissected using cellular assays, western blots, CRISPR-Cas9 gene knockouts, pharmacological inhibitors of PAR2 and downstream signalling proteins in OV90 cancer cells. KEY RESULTS PAR2 was significantly overexpressed in clinical ovarian cancer tissues and in OV90 ovarian cancer cells. PAR2 agonists, an endogenous protease (trypsin) and a synthetic peptide (2f-LIGRL-NH2 ), induced migration and invasion of OV90 ovarian cancer cells through activating a combination of Gαq/11 , Gα12/13 and β-arrestin1/2, but not Gαs or Gαi . This novel cooperative rather than parallel signalling resulted in downstream serial activation of Src kinases, then transactivation of epidermal growth factor receptor (EGFR), followed by downstream MEK-ERK1/2-FOS/MYC/STAT3-COX2 signalling. Either a PAR2 antagonist (I-191), CRISPR-Cas9 gene knockouts (PAR2 or Gα proteins or β-arrestin1/2), or inhibitors of each downstream protein attenuated human ovarian cancer cell motility. CONCLUSION AND IMPLICATIONS This study highlights a novel shared signalling cascade, requiring each of Gαq/11 , Gα12/13 and β-arrestin1/2 for PAR2-induced ovarian cancer cell migration and invasion. This mechanism controlling a cellular function is unusual in not being linked to a specific individual G protein or β-arrestin-mediated signalling pathway.
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Affiliation(s)
- Yuhong Jiang
- Centre for Inflammation and Disease Research and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Junxian Lim
- Centre for Inflammation and Disease Research and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Kai-Chen Wu
- Centre for Inflammation and Disease Research and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Weijun Xu
- Centre for Inflammation and Disease Research and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Jacky Y Suen
- Centre for Inflammation and Disease Research and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - David P Fairlie
- Centre for Inflammation and Disease Research and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
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154
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Bondar A, Lazar J. Optical sensors of heterotrimeric G protein signaling. FEBS J 2020; 288:2570-2584. [DOI: 10.1111/febs.15655] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/26/2020] [Accepted: 12/03/2020] [Indexed: 01/14/2023]
Affiliation(s)
- Alexey Bondar
- Center for Nanobiology and Structural Biology Institute of Microbiology of the Czech Academy of Sciences Nove Hrady Czech Republic
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague Czech Republic
- Faculty of Science University of South Bohemia Ceske Budejovice Czech Republic
| | - Josef Lazar
- Center for Nanobiology and Structural Biology Institute of Microbiology of the Czech Academy of Sciences Nove Hrady Czech Republic
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague Czech Republic
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155
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Bele S, Girada SB, Ray A, Gupta A, Oruganti S, Prakash Babu P, Rayalla RSR, Kalivendi SV, Ibrahim A, Puri V, Adalla V, Katika MR, DiMarchi R, Mitra P. MS-275, a class 1 histone deacetylase inhibitor augments glucagon-like peptide-1 receptor agonism to improve glycemic control and reduce obesity in diet-induced obese mice. eLife 2020; 9:e52212. [PMID: 33349332 PMCID: PMC7755393 DOI: 10.7554/elife.52212] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/06/2020] [Indexed: 12/20/2022] Open
Abstract
Given its glycemic efficacy and ability to reduce the body weight, glucagon-like peptide 1 receptor (GLP-1R) agonism has emerged as a preferred treatment for diabetes associated with obesity. We here report that a small-molecule Class 1 histone deacetylase (HDAC) inhibitor Entinostat (MS-275) enhances GLP-1R agonism to potentiate glucose-stimulated insulin secretion and decrease body weight in diet-induced obese (DIO) mice. MS-275 is not an agonist or allosteric activator of GLP-1R but enhances the sustained receptor-mediated signaling through the modulation of the expression of proteins involved in the signaling pathway. MS-275 and liraglutide combined therapy improved fasting glycemia upon short-term treatment and a chronic administration causes a reduction of obesity in DIO mice. Overall, our results emphasize the therapeutic potential of MS-275 as an adjunct to GLP-1R therapy in the treatment of diabetes and obesity.
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Affiliation(s)
- Shilpak Bele
- Dr. Reddy’s Institute of Life Sciences University of Hyderabad CampusHyderabadIndia
- Manipal Academy of Higher EducationManipalIndia
| | - Shravan Babu Girada
- Dr. Reddy’s Institute of Life Sciences University of Hyderabad CampusHyderabadIndia
| | - Aramita Ray
- Dr. Reddy’s Institute of Life Sciences University of Hyderabad CampusHyderabadIndia
| | - Abhishek Gupta
- Department of Biomedical Sciences and Diabetes Institute, Ohio UniversityAthensUnited States
| | - Srinivas Oruganti
- Dr. Reddy’s Institute of Life Sciences University of Hyderabad CampusHyderabadIndia
| | | | | | | | - Ahamed Ibrahim
- Division of Lipid Chemistry, National Institute of Nutrition HyderabadHyderabadIndia
| | - Vishwajeet Puri
- Department of Biomedical Sciences and Diabetes Institute, Ohio UniversityAthensUnited States
| | - Venkateswar Adalla
- Medical Genomics, QIMR Berghofer Medical Research InstituteHerstonAustralia
| | - Madhumohan R Katika
- Stem Cell and Regenerative Medicine Department, Nizam’s Institute of Medical SciencesHyderabadIndia
| | - Richard DiMarchi
- Department of Chemistry, Indiana UniversityBloomingtonUnited States
| | - Prasenjit Mitra
- Dr. Reddy’s Institute of Life Sciences University of Hyderabad CampusHyderabadIndia
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156
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Sun Y, Zhang D, Ma ML, Lin H, Song Y, Wang J, Ma C, Yu K, An W, Guo S, He D, Yang Z, Xiao P, Hou G, Yu X, Sun JP. Optimization of a peptide ligand for the adhesion GPCR ADGRG2 provides a potent tool to explore receptor biology. J Biol Chem 2020; 296:100174. [PMID: 33303626 PMCID: PMC7948503 DOI: 10.1074/jbc.ra120.014726] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 12/06/2020] [Accepted: 12/10/2020] [Indexed: 12/11/2022] Open
Abstract
The adhesion GPCR ADGRG2, also known as GPR64, is a critical regulator of male fertility that maintains ion/pH homeostasis and CFTR coupling. The molecular basis of ADGRG2 function is poorly understood, in part because no endogenous ligands for ADGRG2 have been reported, thus limiting the tools available to interrogate ADGRG2 activity. It has been shown that ADGRG2 can be activated by a peptide, termed p15, derived from its own N-terminal region known as the Stachel sequence. However, the low affinity of p15 limits its utility for ADGRG2 characterization. In the current study, we used alanine scanning mutagenesis to examine the critical residues responsible for p15-induced ADGRG2 activity. We next designed systematic strategies to optimize the peptide agonist of ADGRG2, using natural and unnatural amino acid substitutions. We obtained an optimized ADGRG2 Stachel peptide T1V/F3Phe(4-Me) (VPM-p15) that activated ADGRG2 with significantly improved (>2 orders of magnitude) affinity. We then characterized the residues in ADGRG2 that were important for ADGRG2 activation in response to VPM-p15 engagement, finding that the toggle switch W6.53 and residues of the ECL2 region of ADGRG2 are key determinants for VPM-p15 interactions and VPM-p15-induced Gs or arrestin signaling. Our study not only provides a useful tool to investigate the function of ADGRG2 but also offers new insights to guide further optimization of Stachel peptides to activate adhesion GPCR members.
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Affiliation(s)
- Yujing Sun
- School of Pharmacy, Binzhou Medical University, Yantai, Shandong, China; Department of Endocrinology, Cheeloo College of Medicine, Qilu Hospital, Shandong University, Jinan, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Daolai Zhang
- School of Pharmacy, Binzhou Medical University, Yantai, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Ming-Liang Ma
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Hui Lin
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Youchen Song
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Junyan Wang
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Chuanshun Ma
- School of Pharmacy, Binzhou Medical University, Yantai, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Ke Yu
- School of Pharmacy, Binzhou Medical University, Yantai, Shandong, China
| | - Wentao An
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Shengchao Guo
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Dongfang He
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Zhao Yang
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Peng Xiao
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Guige Hou
- School of Pharmacy, Binzhou Medical University, Yantai, Shandong, China
| | - Xiao Yu
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China.
| | - Jin-Peng Sun
- School of Pharmacy, Binzhou Medical University, Yantai, Shandong, China; Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, China; Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Ministry of Education, Beijing, China.
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157
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Calebiro D, Koszegi Z, Lanoiselée Y, Miljus T, O'Brien S. G protein-coupled receptor-G protein interactions: a single-molecule perspective. Physiol Rev 2020; 101:857-906. [PMID: 33331229 DOI: 10.1152/physrev.00021.2020] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) regulate many cellular and physiological processes, responding to a diverse range of extracellular stimuli including hormones, neurotransmitters, odorants, and light. Decades of biochemical and pharmacological studies have provided fundamental insights into the mechanisms of GPCR signaling. Thanks to recent advances in structural biology, we now possess an atomistic understanding of receptor activation and G protein coupling. However, how GPCRs and G proteins interact in living cells to confer signaling efficiency and specificity remains insufficiently understood. The development of advanced optical methods, including single-molecule microscopy, has provided the means to study receptors and G proteins in living cells with unprecedented spatio-temporal resolution. The results of these studies reveal an unexpected level of complexity, whereby GPCRs undergo transient interactions among themselves as well as with G proteins and structural elements of the plasma membrane to form short-lived signaling nanodomains that likely confer both rapidity and specificity to GPCR signaling. These findings may provide new strategies to pharmaceutically modulate GPCR function, which might eventually pave the way to innovative drugs for common diseases such as diabetes or heart failure.
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Affiliation(s)
- Davide Calebiro
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Zsombor Koszegi
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Yann Lanoiselée
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Tamara Miljus
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Shannon O'Brien
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
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158
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Barbadin selectively modulates FPR2-mediated neutrophil functions independent of receptor endocytosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118849. [DOI: 10.1016/j.bbamcr.2020.118849] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022]
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159
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Sposini S, De Pascali F, Richardson R, Sayers NS, Perrais D, Yu HN, Palmer S, Nataraja S, Reiter E, Hanyaloglu AC. Pharmacological Programming of Endosomal Signaling Activated by Small Molecule Ligands of the Follicle Stimulating Hormone Receptor. Front Pharmacol 2020; 11:593492. [PMID: 33329002 PMCID: PMC7734412 DOI: 10.3389/fphar.2020.593492] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/19/2020] [Indexed: 12/23/2022] Open
Abstract
Follicle-stimulating hormone receptor (FSHR) is a G protein-coupled receptor (GPCR) with pivotal roles in reproduction. One key mechanism dictating the signal activity of GPCRs is membrane trafficking. After binding its hormone FSH, FSHR undergoes internalization to very early endosomes (VEEs) for its acute signaling and sorting to a rapid recycling pathway. The VEE is a heterogeneous compartment containing the Adaptor Protein Phosphotyrosine Interacting with Pleckstrin homology Domain and Leucine Zipper 1 (APPL1) with distinct functions in regulating endosomal Gαs/cAMP signaling and rapid recycling. Low molecular weight (LMW) allosteric FSHR ligands were developed for use in assisted reproductive technology yet could also provide novel pharmacological tools to study FSHR. Given the critical nature of receptor internalization and endosomal signaling for FSHR activity, we assessed whether these compounds exhibit differential abilities to alter receptor endosomal trafficking and signaling within the VEE. Two chemically distinct LMW agonists (benzamide, termed B3 and thiazolidinone, termed T1) were employed. T1 was able to induce a greater level of cAMP than FSH and B3. As cAMP signaling drives gonadotrophin hormone receptor recycling, rapid exocytic events were evaluated at single event resolution. Strikingly, T1 was able to induce a 3-fold increase in recycling events compared to FSH and two-fold more compared to B3. As T1-induced internalization was only marginally greater, the dramatic increase in recycling and cAMP signaling may be due to additional mechanisms. All compounds exhibited a similar requirement for receptor internalization to increase cAMP and proportion of FSHR endosomes with active Gαs, suggesting regulation of cAMP signaling induced by T1 may be altered. APPL1 plays a central role for GPCRs targeted to the VEE, and indeed, loss of APPL1 inhibited FSH-induced recycling and increased endosomal cAMP signaling. While T1-induced FSHR recycling was APPL1-dependent, its elevated cAMP signaling was only partially increased following APPL1 knockdown. Unexpectedly, B3 altered the dependence of FSHR to APPL1 in an opposing manner, whereby its endosomal signaling was negatively regulated by APPL1, while B3-induced FSHR recycling was APPL1-independent. Overall, FSHR allosteric compounds have the potential to re-program FSHR activity via altering engagement with VEE machinery and also suggests that these two distinct functions of APPL1 can potentially be selected pharmacologically.
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Affiliation(s)
- Silvia Sposini
- Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Francesco De Pascali
- Physiologie de la Reproduction et des Comportements (PRC), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS), Université de Tours, Institut Français du Cheval et de l'Equitation (IFCE), Nouzilly, France
| | - Rachel Richardson
- Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Niamh S. Sayers
- Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - David Perrais
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Henry N. Yu
- CanWell Pharma Inc., Wellesley, MA, United States
| | - Stephen Palmer
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
| | | | - Eric Reiter
- Physiologie de la Reproduction et des Comportements (PRC), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre National de la Recherche Scientifique (CNRS), Université de Tours, Institut Français du Cheval et de l'Equitation (IFCE), Nouzilly, France
| | - Aylin C. Hanyaloglu
- Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
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160
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Patel M, Finlay DB, Glass M. Biased agonism at the cannabinoid receptors - Evidence from synthetic cannabinoid receptor agonists. Cell Signal 2020; 78:109865. [PMID: 33259937 DOI: 10.1016/j.cellsig.2020.109865] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/18/2020] [Accepted: 11/26/2020] [Indexed: 01/14/2023]
Abstract
The type 1 and type 2 cannabinoid receptors are G protein-coupled receptors implicated in a variety of physiological processes and diseases. Synthetic cannabinoid receptor agonists (SCRAs) were originally developed to explore the therapeutic benefits of cannabinoid receptor activation, although more recently, these compounds have been diverted to the recreational drug market and are increasingly associated with incidences of toxicity. A prominent concept in contemporary pharmacology is functional selectivity or biased agonism, which describes the ability of ligands to elicit differential activation of signalling pathways through stabilisation of distinct receptor conformations. Biased agonists may maximise drug effectiveness by reducing on-target adverse effects if they are mediated by signalling pathways distinct from those that drive the therapeutic effects. For the cannabinoid receptors, it remains unclear as to which signalling pathways mediate desirable and adverse effects. However, given their structural diversity and potential to induce a plethora of signalling effects, SCRAs provide the most promising prospect for detecting and studying bias at the cannabinoid receptors. This review summarises the emerging evidence of SCRA bias at the cannabinoid receptors.
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Affiliation(s)
- Monica Patel
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - David B Finlay
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - Michelle Glass
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand.
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161
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Vishnivetskiy SA, Huh EK, Gurevich EV, Gurevich VV. The finger loop as an activation sensor in arrestin. J Neurochem 2020; 157:1138-1152. [PMID: 33159335 DOI: 10.1111/jnc.15232] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/23/2020] [Accepted: 11/01/2020] [Indexed: 12/31/2022]
Abstract
The finger loop in the central crest of the receptor-binding site of arrestins engages the cavity between the transmembrane helices of activated G-protein-coupled receptors. Therefore, it was hypothesized to serve as the sensor that detects the activation state of the receptor. We performed comprehensive mutagenesis of the finger loop in bovine visual arrestin-1, generated mutant radiolabeled proteins by cell-free translation, and determined the effects of mutations on the in vitro binding of arrestin-1 to purified phosphorylated light-activated rhodopsin. This interaction is driven by two factors, rhodopsin activation and rhodopsin-attached phosphates. Therefore, the binding of arrestin-1 to light-activated unphosphorylated rhodopsin is low. To evaluate the role of the finger loop specifically in the recognition of the active receptor conformation, we tested the effects of these mutations in the context of truncated arrestin-1 that demonstrates much higher binding to unphosphorylated activated and phosphorylated inactive rhodopsin. The majority of finger loop residues proved important for arrestin-1 binding to light-activated rhodopsin, with six mutations affecting the binding exclusively to this form. Thus, the finger loop is the key element of arrestin-1 activation sensor. The data also suggest that arrestin-1 and its enhanced mutant bind various functional forms of rhodopsin differently.
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Affiliation(s)
| | - Elizabeth K Huh
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
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162
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Crilly SE, Puthenveedu MA. Compartmentalized GPCR Signaling from Intracellular Membranes. J Membr Biol 2020; 254:259-271. [PMID: 33231722 DOI: 10.1007/s00232-020-00158-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/11/2020] [Indexed: 12/21/2022]
Abstract
G protein-coupled receptors (GPCRs) are integral membrane proteins that transduce a wide array of inputs including light, ions, hormones, and neurotransmitters into intracellular signaling responses which underlie complex processes ranging from vision to learning and memory. Although traditionally thought to signal primarily from the cell surface, GPCRs are increasingly being recognized as capable of signaling from intracellular membrane compartments, including endosomes, the Golgi apparatus, and nuclear membranes. Remarkably, GPCR signaling from these membranes produces functional effects that are distinct from signaling from the plasma membrane, even though often the same G protein effectors and second messengers are activated. In this review, we will discuss the emerging idea of a "spatial bias" in signaling. We will present the evidence for GPCR signaling through G protein effectors from intracellular membranes, and the ways in which this signaling differs from canonical plasma membrane signaling with important implications for physiology and pharmacology. We also highlight the potential mechanisms underlying spatial bias of GPCR signaling, including how intracellular membranes and their associated lipids and proteins affect GPCR activity and signaling.
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Affiliation(s)
- Stephanie E Crilly
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Manojkumar A Puthenveedu
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
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163
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Modular transient nanoclustering of activated β2-adrenergic receptors revealed by single-molecule tracking of conformation-specific nanobodies. Proc Natl Acad Sci U S A 2020; 117:30476-30487. [PMID: 33214152 DOI: 10.1073/pnas.2007443117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
None of the current superresolution microscopy techniques can reliably image the changes in endogenous protein nanoclustering dynamics associated with specific conformations in live cells. Single-domain nanobodies have been invaluable tools to isolate defined conformational states of proteins, and we reasoned that expressing these nanobodies coupled to single-molecule imaging-amenable tags could allow superresolution analysis of endogenous proteins in discrete conformational states. Here, we used anti-GFP nanobodies tagged with photoconvertible mEos expressed as intrabodies, as a proof-of-concept to perform single-particle tracking on a range of GFP proteins expressed in live cells, neurons, and small organisms. We next expressed highly specialized nanobodies that target conformation-specific endogenous β2-adrenoreceptor (β2-AR) in neurosecretory cells, unveiling real-time mobility behaviors of activated and inactivated endogenous conformers during agonist treatment in living cells. We showed that activated β2-AR (Nb80) is highly immobile and organized in nanoclusters. The Gαs-GPCR complex detected with Nb37 displayed higher mobility with surprisingly similar nanoclustering dynamics to that of Nb80. Activated conformers are highly sensitive to dynamin inhibition, suggesting selective targeting for endocytosis. Inactivated β2-AR (Nb60) molecules are also largely immobile but relatively less sensitive to endocytic blockade. Expression of single-domain nanobodies therefore provides a unique opportunity to capture highly transient changes in the dynamic nanoscale organization of endogenous proteins.
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164
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Cheloha RW, Harmand TJ, Wijne C, Schwartz TU, Ploegh HL. Exploring cellular biochemistry with nanobodies. J Biol Chem 2020; 295:15307-15327. [PMID: 32868455 PMCID: PMC7650250 DOI: 10.1074/jbc.rev120.012960] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 08/27/2020] [Indexed: 12/21/2022] Open
Abstract
Reagents that bind tightly and specifically to biomolecules of interest remain essential in the exploration of biology and in their ultimate application to medicine. Besides ligands for receptors of known specificity, agents commonly used for this purpose are monoclonal antibodies derived from mice, rabbits, and other animals. However, such antibodies can be expensive to produce, challenging to engineer, and are not necessarily stable in the context of the cellular cytoplasm, a reducing environment. Heavy chain-only antibodies, discovered in camelids, have been truncated to yield single-domain antibody fragments (VHHs or nanobodies) that overcome many of these shortcomings. Whereas they are known as crystallization chaperones for membrane proteins or as simple alternatives to conventional antibodies, nanobodies have been applied in settings where the use of standard antibodies or their derivatives would be impractical or impossible. We review recent examples in which the unique properties of nanobodies have been combined with complementary methods, such as chemical functionalization, to provide tools with unique and useful properties.
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Affiliation(s)
- Ross W Cheloha
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA
| | - Thibault J Harmand
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA
| | - Charlotte Wijne
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA
| | - Thomas U Schwartz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Hidde L Ploegh
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA; Harvard Medical School, Boston, Massachusetts, USA.
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165
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Zhang M, Wang Q, Sun X, Yin Q, Chen J, Xu L, Xu C. β 2 -adrenergic receptor signaling drives prostate cancer progression by targeting the Sonic hedgehog-Gli1 signaling activation. Prostate 2020; 80:1328-1340. [PMID: 32894788 PMCID: PMC7540401 DOI: 10.1002/pros.24060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 08/05/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND Considerable evidence suggests that the sympathetic nervous system, mainly via adrenergic signaling, contributes to prostate cancer (PCa) progression. However, the underlying molecular mechanisms remain unknown. METHODS The expression level of β2 -adrenergic receptor (β2 -AR) in tissue microarray was evaluated by immunohistochemistry. The effects of isoproterenol (ISO) or Sonic Hedgehog (Shh) signaling inhibitor on tumor growth were analyzed in proliferation and colony formation assays. The apoptosis of cells was analyzed by flow cytometry. Small hairpin RNA-based knockdown of β2 -AR or Gli1 was validated by Western blot analysis and real-time PCR. Effects of β2 -AR on prostate carcinogenesis in vivo were observed in a mouse xenograft model. The expression levels of the indicated proteins in xenograft tissues were evaluated by immunohistochemistry. Expression levels of Shh signaling components and downstream proteins were assessed by immunoblotting. RESULTS We determined that β2 -AR was expressed at significantly higher levels in carcinoma than in normal prostate tissues. β2 -AR signaling also played an essential role in sustaining PCa cell proliferation in vivo and in vitro. We also found that inhibition of Shh signaling or knockdown of Gli1 expression significantly restrained ISO-induced cell proliferation in vitro. ISO alleviated the apoptosis induced by suppressing or knocking down of Gli1. The β2 -AR agonist ISO upregulated the transcription and protein expression of target genes of Shh signaling, including c-Myc, Cyclin D1, and VEGFA. Conversely, knocking down β2 -AR markedly suppressed the expression of Shh components in vivo and in vitro. In Gli1 knockdown cells, ISO failed to increase the expression of target genes of Shh signaling. CONCLUSIONS In this study, we uncovered an important role of β2 -AR signaling in regulating the Shh pathway activity in PCa tumorigenesis and provide further insight into the mechanism of the involvement of the Hh signaling pathway. Furthermore, given the efficacy of β2 -adrenergic modulation on PCa, our study might also add evidence for potential therapeutic options of β-blockers for PCa.
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Affiliation(s)
- Mi Zhang
- Institute of Life SciencesChongqing Medical UniversityChongqingChina
| | - Qianhui Wang
- Institute of Life SciencesChongqing Medical UniversityChongqingChina
| | - Xueqing Sun
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory of Tumor Microenvironment and InflammationShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Qingqing Yin
- Institute of Life SciencesChongqing Medical UniversityChongqingChina
| | - Jinying Chen
- Institute of Life SciencesChongqing Medical UniversityChongqingChina
| | - Linhui Xu
- Institute of Life SciencesChongqing Medical UniversityChongqingChina
| | - Chen Xu
- Institute of Life SciencesChongqing Medical UniversityChongqingChina
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166
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Kaiser A, Wanka L, Ziffert I, Beck-Sickinger AG. Biased agonists at the human Y 1 receptor lead to prolonged membrane residency and extended receptor G protein interaction. Cell Mol Life Sci 2020; 77:4675-4691. [PMID: 31919571 PMCID: PMC11104783 DOI: 10.1007/s00018-019-03432-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/02/2019] [Accepted: 12/18/2019] [Indexed: 02/06/2023]
Abstract
Functionally selective ligands to address specific cellular responses downstream of G protein-coupled receptors (GPCR) open up new possibilities for therapeutics. We designed and characterized novel subtype- and pathway-selective ligands. Substitution of position Q34 of neuropeptide Y to glycine (G34-NPY) results in unprecedented selectivity over all other YR subtypes. Moreover, this ligand displays a significant bias towards activation of the Gi/o pathway over recruitment of arrestin-3. Notably, no bias is observed for an established Y1R versus Y2R selective ligand carrying a proline at position 34 (F7,P34-NPY). Next, we investigated the spatio-temporal signaling at the Y1R and demonstrated that G protein-biased ligands promote a prolonged localization at the cell membrane, which leads to enhanced G protein signaling, while endosomal receptors do not contribute to cAMP signaling. Thus, spatial components are critical for the signaling of the Y1R that can be modulated by tailored ligands and represent a novel mode for biased pathways.
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Affiliation(s)
- Anette Kaiser
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, 04103, Leipzig, Germany
| | - Lizzy Wanka
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, 04103, Leipzig, Germany
| | - Isabelle Ziffert
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, 04103, Leipzig, Germany
| | - Annette G Beck-Sickinger
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, 04103, Leipzig, Germany.
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167
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Droctové L, Lancien M, Tran VL, Susset M, Jego B, Theodoro F, Kessler P, Mourier G, Robin P, Diarra SS, Palea S, Flahault A, Chorfa A, Corbani M, Llorens-Cortes C, Mouillac B, Mendre C, Pruvost A, Servent D, Truillet C, Gilles N. A snake toxin as a theranostic agent for the type 2 vasopressin receptor. Am J Cancer Res 2020; 10:11580-11594. [PMID: 33052234 PMCID: PMC7545998 DOI: 10.7150/thno.47485] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/04/2020] [Indexed: 01/01/2023] Open
Abstract
Rationale: MQ1, a snake toxin which targets with high nanomolar affinity and absolute selectivity for the type 2 vasopressin receptor (V2R), is a drug candidate for renal diseases and a molecular probe for imaging cells or organs expressing V2R. Methods: MQ1's pharmacological properties were characterized and applied to a rat model of hyponatremia. Its PK/PD parameters were determined as well as its therapeutic index. Fluorescently and radioactively labeled MQ1 were chemically synthesized and associated with moderate loss of affinity. MQ1's dynamic biodistribution was monitored by positron emission tomography. Confocal imaging was used to observe the labeling of three cancer cell lines. Results: The inverse agonist property of MQ1 very efficiently prevented dDAVP-induced hyponatremia in rats with low nanomolar/kg doses and with a very large therapeutic index. PK (plasma MQ1 concentrations) and PD (diuresis) exhibited a parallel biphasic decrease. The dynamic biodistribution showed that MQ1 targets the kidneys and then exhibits a blood and kidney biphasic decrease. Whatever the approach used, we found a T1/2α between 0.9 and 3.8 h and a T1/2β between 25 and 46 h and demonstrated that the kidneys were able to retain MQ1. Finally, the presence of functional V2R expressed at the membrane of cancer cells was, for the first time, demonstrated with a specific fluorescent ligand. Conclusion: As the most selective V2 binder, MQ1 is a new promising drug for aquaresis-related diseases and a molecular probe to visualize in vitro and in vivo V2R expressed physiologically or under pathological conditions.
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168
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Nielsen CDT, Dhasmana D, Floresta G, Wohland T, Cilibrizzi A. Illuminating the Path to Target GPCR Structures and Functions. Biochemistry 2020; 59:3783-3795. [PMID: 32956586 DOI: 10.1021/acs.biochem.0c00606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
G-Protein-coupled receptors (GPCRs) are ubiquitous within eukaryotes, responsible for a wide array of physiological and pathological processes. Indeed, the fact that they are the most drugged target in the human genome is indicative of their importance. Despite the clear interest in GPCRs, most information regarding their activity has been so far obtained by analyzing the response from a "bulk medium". As such, this Perspective summarizes some of the common methods for this indirect observation. Nonetheless, by inspecting approaches applying super-resolution imaging, we argue that imaging is perfectly situated to obtain more detailed structural and spatial information, assisting in the development of new GPCR-targeted drugs and clinical strategies. The benefits of direct optical visualization of GPCRs are analyzed in the context of potential future directions in the field.
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Affiliation(s)
- Christian D-T Nielsen
- Imperial College London, White City Campus, Molecular Sciences Research Hub, 80 Wood Lane, London W12 0BZ, U.K
| | - Divya Dhasmana
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Giuseppe Floresta
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, U.K
| | - Thorsten Wohland
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.,Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Agostino Cilibrizzi
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, U.K
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169
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Valdez-Lopez JC, Gebreegziabher M, Bailey RJ, Flores J, Awotunde O, Burnett T, Robinson PR. Protein Phosphatase 2A and Clathrin-Mediated Endocytosis Facilitate Robust Melanopsin Light Responses and Resensitization. Invest Ophthalmol Vis Sci 2020; 61:10. [PMID: 33049058 PMCID: PMC7571330 DOI: 10.1167/iovs.61.12.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Intrinsically photosensitive retinal ganglion cells (ipRGCs) that express the visual pigment melanopsin regulate non-image-forming visual tasks, such as circadian photoentrainment and pupil constriction, as well as contrast detection for image formation. Sustained ipRGC function throughout the day is, therefore, of great importance. Melanopsin is a bistable rhabdomeric-type (R-type) visual pigment, which is thought to use light to regenerate its chromophore from all-trans-retinal back to 11-cis-retinal and does not depend on constant chromophore supply to the extent required by visual pigment in rod and cone photoreceptors. Like the majority of photopigments and G-protein-coupled receptors (GPCRs), melanopsin deactivation requires C-terminal phosphorylation and subsequent β-arrestin binding. We hypothesize that melanopsin utilizes canonical GPCR resensitization mechanisms, including dephosphorylation and endocytosis, during the light, and together, they provide a mechanism for prolonged light responses. Methods Here, we examined expression of protein phosphatases from a variety of subfamilies by RT-PCR and immunohistochemical analyses of the mouse retina. The expression of protein phosphatase 2A (PP2A) in ipRGCs was assessed. We also examine the role of phosphatase and endocytic activity in sustaining melanopsin signaling using transiently-transfected HEK293 cells. Results Our analyses suggest that melanopsin-mediated light responses can be rapidly and extensively enhanced by PP2A activity. Light-activated melanopsin undergoes endocytosis in a clathrin-dependent manner. This endocytic activity enhances light responses upon repeated stimulation, implicating a role for endocytic activity in resensitization. Conclusions Thus, we propose that melanopsin phototransduction is maintained by utilizing canonical GPCR resensitization mechanisms rather than reliance on chromophore replenishment from supporting cells.
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Affiliation(s)
- Juan C Valdez-Lopez
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States
| | - Meheret Gebreegziabher
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States.,National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Robin J Bailey
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States
| | - Jair Flores
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States
| | - Olanike Awotunde
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States
| | - Thomas Burnett
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Phyllis R Robinson
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States
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170
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Muratspahić E, Koehbach J, Gruber CW, Craik DJ. Harnessing cyclotides to design and develop novel peptide GPCR ligands. RSC Chem Biol 2020; 1:177-191. [PMID: 34458757 PMCID: PMC8341132 DOI: 10.1039/d0cb00062k] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/10/2020] [Indexed: 12/13/2022] Open
Abstract
Cyclotides are plant-derived cyclic, disulfide-rich peptides with a unique cyclic cystine knot topology that confers them with remarkable structural stability and resistance to proteolytic degradation. Recently, cyclotides have emerged as promising scaffold molecules for designing peptide-based therapeutics. Here, we provide examples of how engineering cyclotides using molecular grafting may lead to the development of novel peptide ligands of G protein-coupled receptors (GPCRs), today's most exploited drug targets. Integrating bioactive epitopes into stable cyclotide scaffolds can lead to improved pharmacokinetics and oral activity as well as selectivity and high enzymatic stability. We also discuss and highlight the importance of engineered cyclotides as novel tools to study GPCR signaling.
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Affiliation(s)
- Edin Muratspahić
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna Austria
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland Brisbane Queensland 4072 Australia
| | - Johannes Koehbach
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland Brisbane Queensland 4072 Australia
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna Austria
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland Brisbane Queensland 4072 Australia
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171
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Babwah AV. The wonderful and masterful G protein-coupled receptor (GPCR): A focus on signaling mechanisms and the neuroendocrine control of fertility. Mol Cell Endocrinol 2020; 515:110886. [PMID: 32574585 DOI: 10.1016/j.mce.2020.110886] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/08/2020] [Accepted: 05/20/2020] [Indexed: 12/18/2022]
Abstract
Human GnRH deficiency, both clinically and genetically, is a heterogeneous disorder comprising of congenital GnRH deficiency with anosmia (Kallmann syndrome), or with normal olfaction [normosmic idiopathic hypogonadotropic hypogonadism (IHH)], and adult-onset hypogonadotropic hypogonadism. Our understanding of the neural mechanisms underlying GnRH secretion and GnRH signaling continues to increase at a rapid rate and strikingly, the heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) continue to emerge as essential players in these processes. GPCRs were once viewed as binary on-off switches, where in the "on" state they are bound to their Gα protein, but now we understand that view is overly simplistic and does not adequately characterize GPCRs. Instead, GPCRs have emerged as masterful signaling molecules exploiting different physical conformational states of itself to elicit an array of downstream signaling events via their G proteins and the β-arrestins. The "one receptor-multiple signaling conformations" model is likely an evolved strategy that can be used to our advantage as researchers have shown that targeting specific receptor conformations via biased ligands is proving to be a powerful tool in the effective treatment of human diseases. Can biased ligands be used to selectively modulate signaling by GPCR regulators of the neuroendocrine axis in the treatment of IHH? As discussed in this review, the grand possibility exists. However, while we are still very far from developing these treatments, this exciting likelihood can happen through a much greater mechanistic understanding of how GPCRs signal within the cell.
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Affiliation(s)
- Andy V Babwah
- Department of Pediatrics, Laboratory of Human Growth and Reproductive Development, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States; Child Health Institute of New Jersey, New Brunswick, NJ, United States.
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172
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Böttke T, Ernicke S, Serfling R, Ihling C, Burda E, Gurevich VV, Sinz A, Coin I. Exploring GPCR-arrestin interfaces with genetically encoded crosslinkers. EMBO Rep 2020; 21:e50437. [PMID: 32929862 PMCID: PMC7645262 DOI: 10.15252/embr.202050437] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 08/10/2020] [Accepted: 08/13/2020] [Indexed: 12/18/2022] Open
Abstract
β‐arrestins (βarr1 and βarr2) are ubiquitous regulators of G protein‐coupled receptor (GPCR) signaling. Available data suggest that β‐arrestins dock to different receptors in different ways. However, the structural characterization of GPCR‐arrestin complexes is challenging and alternative approaches to study GPCR‐arrestin complexes are needed. Here, starting from the finger loop as a major site for the interaction of arrestins with GPCRs, we genetically incorporate non‐canonical amino acids for photo‐ and chemical crosslinking into βarr1 and βarr2 and explore binding topologies to GPCRs forming either stable or transient complexes with arrestins: the vasopressin receptor 2 (rhodopsin‐like), the corticotropin‐releasing factor receptor 1, and the parathyroid hormone receptor 1 (both secretin‐like). We show that each receptor leaves a unique footprint on arrestins, whereas the two β‐arrestins yield quite similar crosslinking patterns. Furthermore, we show that the method allows defining the orientation of arrestin with respect to the GPCR. Finally, we provide direct evidence for the formation of arrestin oligomers in the cell.
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Affiliation(s)
- Thore Böttke
- Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
| | - Stefan Ernicke
- Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
| | - Robert Serfling
- Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
| | - Christian Ihling
- Institute of Pharmacy, Department of Pharmaceutical Chemistry and Bioanalytics, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Edyta Burda
- Institute of Pharmacy, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | | | - Andrea Sinz
- Institute of Pharmacy, Department of Pharmaceutical Chemistry and Bioanalytics, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Irene Coin
- Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
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173
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Bao Z, Zhou S, Zhou H. Sorting Nexin 27 as a potential target in G protein‑coupled receptor recycling for cancer therapy (Review). Oncol Rep 2020; 44:1779-1786. [PMID: 33000258 PMCID: PMC7551096 DOI: 10.3892/or.2020.7766] [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: 02/28/2020] [Accepted: 08/10/2020] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are the largest family of membrane receptors and activate several downstream signaling pathways involved in numerous physiological cellular processes. GPCRs are usually internalized and desensitized by intracellular signals. Numerous studies have shown that several GPCRs interact with sorting nexin 27 (SNX27), a cargo selector of the retromer complex, and are recycled from endosomes to the plasma membrane. Recycled GPCRs usually contain specific C-terminal postsynaptic density protein 95/Discs large protein/Zonula occludens 1 (PDZ) binding motifs, which are specifically recognized by SNX27, and return to the cell surface as functionally naïve receptors. Aberrant endosome-to-membrane recycling of GPCRs mediated by SNX27 may serve a critical role in cancer growth and development. Therefore, SNX27 may be a novel target for cancer therapies.
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Affiliation(s)
- Zixu Bao
- Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Shijun Zhou
- Department of Infectious Disease, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230601, P.R. China
| | - Haisheng Zhou
- Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032, P.R. China
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174
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Gambardella J, Sorriento D, Bova M, Rusciano M, Loffredo S, Wang X, Petraroli A, Carucci L, Mormile I, Oliveti M, Bruno Morelli M, Fiordelisi A, Spadaro G, Campiglia P, Sala M, Trimarco B, Iaccarino G, Santulli G, Ciccarelli M. Role of Endothelial G Protein-Coupled Receptor Kinase 2 in Angioedema. Hypertension 2020; 76:1625-1636. [PMID: 32895019 DOI: 10.1161/hypertensionaha.120.15130] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Excessive BK (bradykinin) stimulation is responsible for the exaggerated permeabilization of the endothelium in angioedema. However, the molecular mechanisms underlying these responses have not been investigated. BK receptors are Gq-protein-coupled receptors phosphorylated by GRK2 (G protein-coupled receptor kinase 2) with a hitherto unknown biological and pathophysiological significance. In the present study, we sought to identify the functional role of GRK2 in angioedema through the regulation of BK signaling. We found that the accumulation of cytosolic Ca2+ in endothelial cells induced by BK was sensitive to GRK2 activity, as it was significantly augmented by inhibiting the kinase. Accordingly, permeabilization and NO production induced by BK were enhanced, as well. In vivo, mice with reduced GRK2 levels in the endothelium (Tie2-CRE/GRK2fl+/fl-) exhibited an increased response to BK in terms of vascular permeability and extravasation. Finally, patients with reduced GRK2 levels displayed a severe phenotype of angioedema. Taken together, these findings establish GRK2 as a novel pivotal regulator of BK signaling with an essential role in the pathophysiology of vascular permeability and angioedema.
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Affiliation(s)
- Jessica Gambardella
- From the Department of Advanced Biomedical Science (J.G., D.S., A.F., B.T., G.I., G. Santulli), University of Naples Federico II, NA, Italy.,Division of Cardiology, Department of Medicine, Wilf Family Cardiovascular Research Institute (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism (FIDAM) (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,International Translational Research and Medical Education Consortium (ITME), NA, Italy (J.G., B.T., G. Santulli)
| | - Daniela Sorriento
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Maria Bova
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Mariarosaria Rusciano
- Montevergine Hospital, Mercogliano, Italy (M.R.).,Department of Medicine and Surgery (M.R., M.O., M.C.), University of Salerno, Italy
| | - Stefania Loffredo
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Xujun Wang
- Division of Cardiology, Department of Medicine, Wilf Family Cardiovascular Research Institute (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism (FIDAM) (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY
| | - Angelica Petraroli
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Laura Carucci
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Ilaria Mormile
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Marco Oliveti
- Department of Medicine and Surgery (M.R., M.O., M.C.), University of Salerno, Italy
| | - Marco Bruno Morelli
- Division of Cardiology, Department of Medicine, Wilf Family Cardiovascular Research Institute (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism (FIDAM) (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY
| | - Antonella Fiordelisi
- From the Department of Advanced Biomedical Science (J.G., D.S., A.F., B.T., G.I., G. Santulli), University of Naples Federico II, NA, Italy
| | - Giuseppe Spadaro
- Department of Translational Medical Sciences and Interdepartmental Center for Research in Basic and Clinical Immunology Sciences (M.B., S.L., A.P., L.C., I.M., G. Spadaro), University of Naples Federico II, NA, Italy
| | - Pietro Campiglia
- Division of Biomedicine, Department of Pharmaceutical Science (P.C., M.S.), University of Salerno, Italy
| | - Marina Sala
- Division of Biomedicine, Department of Pharmaceutical Science (P.C., M.S.), University of Salerno, Italy
| | - Bruno Trimarco
- International Translational Research and Medical Education Consortium (ITME), NA, Italy (J.G., B.T., G. Santulli)
| | - Guido Iaccarino
- From the Department of Advanced Biomedical Science (J.G., D.S., A.F., B.T., G.I., G. Santulli), University of Naples Federico II, NA, Italy
| | - Gaetano Santulli
- From the Department of Advanced Biomedical Science (J.G., D.S., A.F., B.T., G.I., G. Santulli), University of Naples Federico II, NA, Italy.,Division of Cardiology, Department of Medicine, Wilf Family Cardiovascular Research Institute (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism (FIDAM) (J.G., X.W., M.B.M., G. Santulli), Albert Einstein College of Medicine, Montefiore University Hospital, NY.,International Translational Research and Medical Education Consortium (ITME), NA, Italy (J.G., B.T., G. Santulli)
| | - Michele Ciccarelli
- Department of Medicine and Surgery (M.R., M.O., M.C.), University of Salerno, Italy
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175
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Koch C, Engele J. Functions of the CXCL12 Receptor ACKR3/CXCR7-What Has Been Perceived and What Has Been Overlooked. Mol Pharmacol 2020; 98:577-585. [PMID: 32883765 DOI: 10.1124/molpharm.120.000056] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/31/2020] [Indexed: 12/18/2022] Open
Abstract
The CXCL12 system is central to the development of many organs and is further crucially engaged in pathophysiological processes underlying cancer, inflammation, and cardiovascular disorders. This disease-associated role presently focuses major interest on the two CXCL12 receptors, CXCR4 and atypical chemokine receptor 3 (ACKR3)/CXCR7, as promising therapeutic targets. Major obstacles in these ongoing efforts are confusing reports on the differential use of either ACKR3/CXCR7 and/or CXCR4 across various cells as well as on the specific function(s) of ACKR3/CXCR7. Although basically no doubts remain that CXCR4 represents a classic chemokine receptor, functions assigned to ACKR3/CXCR7 range from those of a strictly silent scavenger receptor eventually modulating CXCR4 signaling to an active and independent signaling receptor. In this review, we depict a thorough analysis of our present knowledge on different modes of organization and functions of the cellular CXCL12 system. We further highlight the potential role of ACKR3/CXCR7 as a "crosslinker" of different receptor systems. Finally, we discuss mechanisms with the potency to impinge on the cellular organization of the CXCL12 system and hence might represent additional future therapeutic targets. SIGNIFICANCE STATEMENT: Delineating the recognized functions of atypical chemokine receptor 3 and CXCR4 in CXCL12 signaling is central to the more detailed understanding of the role of the CXCL12 system in health and disease and will help to guide future research efforts.
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Affiliation(s)
- Christian Koch
- Institute of Anatomy, University of Leipzig, Medical Faculty, Leipzig, Germany
| | - Jürgen Engele
- Institute of Anatomy, University of Leipzig, Medical Faculty, Leipzig, Germany
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176
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Dwivedi-Agnihotri H, Chaturvedi M, Baidya M, Stepniewski TM, Pandey S, Maharana J, Srivastava A, Caengprasath N, Hanyaloglu AC, Selent J, Shukla AK. Distinct phosphorylation sites in a prototypical GPCR differently orchestrate β-arrestin interaction, trafficking, and signaling. SCIENCE ADVANCES 2020; 6:6/37/eabb8368. [PMID: 32917711 PMCID: PMC7486103 DOI: 10.1126/sciadv.abb8368] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 07/28/2020] [Indexed: 05/14/2023]
Abstract
Agonist-induced phosphorylation of G protein-coupled receptors (GPCRs) is a key determinant for their interaction with β-arrestins (βarrs) and subsequent functional responses. Therefore, it is important to decipher the contribution and interplay of different receptor phosphorylation sites in governing βarr interaction and functional outcomes. Here, we find that several phosphorylation sites in the human vasopressin receptor (V2R), positioned either individually or in clusters, differentially contribute to βarr recruitment, trafficking, and ERK1/2 activation. Even a single phosphorylation site in V2R, suitably positioned to cross-talk with a key residue in βarrs, has a decisive contribution in βarr recruitment, and its mutation results in strong G-protein bias. Molecular dynamics simulation provides mechanistic insights into the pivotal role of this key phosphorylation site in governing the stability of βarr interaction and regulating the interdomain rotation in βarrs. Our findings uncover important structural aspects to better understand the framework of GPCR-βarr interaction and biased signaling.
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Affiliation(s)
- Hemlata Dwivedi-Agnihotri
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Madhu Chaturvedi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Mithu Baidya
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Tomasz Maciej Stepniewski
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Shubhi Pandey
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Jagannath Maharana
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Ashish Srivastava
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Natarin Caengprasath
- Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Hammersmith Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Aylin C Hanyaloglu
- Institute of Reproductive and Developmental Biology, Department of Metabolism, Digestion and Reproduction, Hammersmith Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Jana Selent
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain.
| | - Arun K Shukla
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
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177
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Wingler LM, Lefkowitz RJ. Conformational Basis of G Protein-Coupled Receptor Signaling Versatility. Trends Cell Biol 2020; 30:736-747. [PMID: 32622699 PMCID: PMC7483927 DOI: 10.1016/j.tcb.2020.06.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/07/2020] [Accepted: 06/08/2020] [Indexed: 12/19/2022]
Abstract
G protein-coupled receptors (GPCRs) are privileged structural scaffolds in biology that have the versatility to regulate diverse physiological processes. Interestingly, many GPCR ligands exhibit significant 'bias' - the ability to preferentially activate subsets of the many cellular pathways downstream of these receptors. Recently, complementary information from structural and spectroscopic approaches has made significant inroads into understanding the mechanisms of these biased ligands. The consistently emerging theme is that GPCRs are highly dynamic proteins, and ligands with varying pharmacological properties differentially modulate the equilibrium among multiple conformations. Biased signaling and other recently appreciated complexities of GPCR signaling thus appear to be a natural consequence of the conformational heterogeneity of GPCRs and GPCR-transducer complexes.
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Affiliation(s)
- Laura M Wingler
- Howard Hughes Medical Institute and Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
| | - Robert J Lefkowitz
- Howard Hughes Medical Institute and Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA; Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
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178
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The constitutive activity of the viral-encoded G protein-coupled receptor US28 supports a complex signalling network contributing to cancer development. Biochem Soc Trans 2020; 48:1493-1504. [PMID: 32779712 PMCID: PMC7458396 DOI: 10.1042/bst20190988] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/05/2020] [Accepted: 07/14/2020] [Indexed: 12/23/2022]
Abstract
US28 is a viral G protein-coupled receptor (GPCR) encoded by the human cytomegalovirus (HCMV). This receptor, expressed both during lytic replication and viral latency, is required for latency. US28 is binding to a wide variety of chemokines but also exhibits a particularly high constitutive activity robustly modulating a wide network of cellular pathways altering the host cell environment to benefit HCMV infection. Several studies suggest that US28-mediated signalling may contribute to cancer progression. In this review, we discuss the unique structural characteristics that US28 acquired through evolution that confer a robust constitutive activity to this viral receptor. We also describe the wide downstream signalling network activated by this constitutive activation of US28 and discuss how these signalling pathways may promote and support important cellular aspects of cancer.
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179
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Thibeault PE, Ramachandran R. Biased signaling in platelet G-protein coupled receptors. Can J Physiol Pharmacol 2020; 99:255-269. [PMID: 32846106 DOI: 10.1139/cjpp-2020-0149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Platelets are small megakaryocyte-derived, anucleate, disk-like structures that play an outsized role in human health and disease. Both a decrease in the number of platelets and a variety of platelet function disorders result in petechiae or bleeding that can be life threatening. Conversely, the inappropriate activation of platelets, within diseased blood vessels, remains the leading cause of death and morbidity by affecting heart attacks and stroke. The fine balance of the platelet state in healthy individuals is controlled by a number of receptor-mediated signaling pathways that allow the platelet to rapidly respond and maintain haemostasis. G-protein coupled receptors (GPCRs) are particularly important regulators of platelet function. Here we focus on the major platelet-expressed GPCRs and discuss the roles of downstream signaling pathways (e.g., different G-protein subtypes or β-arrestin) in regulating the different phases of the platelet activation. Further, we consider the potential for selectively targeting signaling pathways that may contribute to platelet responses in disease through development of biased agonists. Such selective targeting of GPCR-mediated signaling pathways by drugs, often referred to as biased signaling, holds promise in delivering therapeutic interventions that do not present significant side effects, especially in finely balanced physiological systems such as platelet activation in haemostasis.
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Affiliation(s)
- Pierre E Thibeault
- Department of Physiology and Pharmacology, University of Western Ontario, 1151 Richmond Street, London, ON N6A5C1, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, 1151 Richmond Street, London, ON N6A5C1, Canada
| | - Rithwik Ramachandran
- Department of Physiology and Pharmacology, University of Western Ontario, 1151 Richmond Street, London, ON N6A5C1, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, 1151 Richmond Street, London, ON N6A5C1, Canada
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180
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Abstract
G protein-coupled receptors (GPCRs) are targeted by a large fraction of approved drugs and regulate many important cellular processes. Association of GPCRs with heterotrimeric G proteins in response to agonist activation is thought to invariably lead to G protein activation. We find instead that G12 heterotrimers can associate with agonist-bound receptors in a manner that does not lead to activation. These unproductive agonist–receptor-G protein ternary complexes sequester G12 heterotrimers and thus inhibit rather than support G12 signaling. These findings reveal a mechanism whereby agonist activation of GPCRs can inhibit as well as promote G protein signaling. G proteins are activated when they associate with G protein-coupled receptors (GPCRs), often in response to agonist-mediated receptor activation. It is generally thought that agonist-induced receptor-G protein association necessarily promotes G protein activation and, conversely, that activated GPCRs do not interact with G proteins that they do not activate. Here we show that GPCRs can form agonist-dependent complexes with G proteins that they do not activate. Using cell-based bioluminescence resonance energy transfer (BRET) and luminescence assays we find that vasopressin V2 receptors (V2R) associate with both Gs and G12 heterotrimers when stimulated with the agonist arginine vasopressin (AVP). However, unlike V2R-Gs complexes, V2R-G12 complexes are not destabilized by guanine nucleotides and do not promote G12 activation. Activating V2R does not lead to signaling responses downstream of G12 activation, but instead inhibits basal G12-mediated signaling, presumably by sequestering G12 heterotrimers. Overexpressing G12 inhibits G protein receptor kinase (GRK) and arrestin recruitment to V2R and receptor internalization. Formyl peptide (FPR1 and FPR2) and Smoothened (Smo) receptors also form complexes with G12 that are insensitive to nucleotides, suggesting that unproductive GPCR-G12 complexes are not unique to V2R. These results indicate that agonist-dependent receptor-G protein association does not always lead to G protein activation and may in fact inhibit G protein activation.
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181
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Zhuo Y, Gurevich VV, Vishnivetskiy SA, Klug CS, Marchese A. A non-GPCR-binding partner interacts with a novel surface on β-arrestin1 to mediate GPCR signaling. J Biol Chem 2020; 295:14111-14124. [PMID: 32753481 DOI: 10.1074/jbc.ra120.015074] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/29/2020] [Indexed: 12/30/2022] Open
Abstract
The multifaceted adaptor protein β-arr1 (β-arrestin1) promotes activation of focal adhesion kinase (FAK) by the chemokine receptor CXCR4, facilitating chemotaxis. This function of β-arr1 requires the assistance of the adaptor protein STAM1 (signal-transducing adaptor molecule 1) because disruption of the interaction between STAM1 and β-arr1 reduces CXCR4-mediated activation of FAK and chemotaxis. To begin to understand the mechanism by which β-arr1 together with STAM1 activates FAK, we used site-directed spin-labeling EPR spectroscopy-based studies coupled with bioluminescence resonance energy transfer-based cellular studies to show that STAM1 is recruited to activated β-arr1 by binding to a novel surface on β-arr1 at the base of the finger loop, at a site that is distinct from the receptor-binding site. Expression of a STAM1-deficient binding β-arr1 mutant that is still able to bind to CXCR4 significantly reduced CXCL12-induced activation of FAK but had no impact on ERK-1/2 activation. We provide evidence of a novel surface at the base of the finger loop that dictates non-GPCR interactions specifying β-arrestin-dependent signaling by a GPCR. This surface might represent a previously unidentified switch region that engages with effector molecules to drive β-arrestin signaling.
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Affiliation(s)
- Ya Zhuo
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Candice S Klug
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Adriano Marchese
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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182
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Spillmann M, Thurner L, Romantini N, Zimmermann M, Meger B, Behe M, Waldhoer M, Schertler GFX, Berger P. New Insights into Arrestin Recruitment to GPCRs. Int J Mol Sci 2020; 21:ijms21144949. [PMID: 32668755 PMCID: PMC7404097 DOI: 10.3390/ijms21144949] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 12/14/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are cellular master regulators that translate extracellular stimuli such as light, small molecules or peptides into a cellular response. Upon ligand binding, they bind intracellular proteins such as G proteins or arrestins, modulating intracellular signaling cascades. Here, we use a protein-fragment complementation approach based on nanoluciferase (split luciferase assay) to assess interaction of all four known human arrestins with four different GPCRs (two class A and two class B receptors) in live cells. Besides directly tagging the 11S split-luciferase subunit to the receptor, we also could demonstrate that membrane localization of the 11S subunit with a CAAX-tag allowed us to probe arrestin recruitment by endogenously expressed GPCRs. Varying the expression levels of our reporter constructs changed the dynamic behavior of our assay, which we addressed with an advanced baculovirus-based multigene expression system. Our detection assay allowed us to probe the relevance of each of the two arrestin binding sites in the different GPCRs for arrestin binding. We observed remarkable differences between the roles of each arresting binding site in the tested GPCRs and propose that the distinct advantages of our system for probing receptor interaction with effector proteins will help elucidate the molecular basis of GPCR signaling efficacy and specificity in different cell types.
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Affiliation(s)
- Martin Spillmann
- Paul Scherrer Institute, Laboratory of Nanoscale Biology, PSI, Forschungsstrasse 111, 5232 Villigen, Switzerland; (M.S.); (L.T.); (B.M.)
| | - Larissa Thurner
- Paul Scherrer Institute, Laboratory of Nanoscale Biology, PSI, Forschungsstrasse 111, 5232 Villigen, Switzerland; (M.S.); (L.T.); (B.M.)
| | - Nina Romantini
- Paul Scherrer Institute, Center for Radiopharmaceutical Sciences (CRS), PSI, Forschungsstrasse 111, 5232 Villigen, Switzerland; (N.R.); (M.B.)
| | - Mirjam Zimmermann
- InterAx Biotech AG, PARK innovAARE, 5234 Villigen, Switzerland; (M.Z.); (M.W.)
| | - Benoit Meger
- Paul Scherrer Institute, Laboratory of Nanoscale Biology, PSI, Forschungsstrasse 111, 5232 Villigen, Switzerland; (M.S.); (L.T.); (B.M.)
| | - Martin Behe
- Paul Scherrer Institute, Center for Radiopharmaceutical Sciences (CRS), PSI, Forschungsstrasse 111, 5232 Villigen, Switzerland; (N.R.); (M.B.)
| | - Maria Waldhoer
- InterAx Biotech AG, PARK innovAARE, 5234 Villigen, Switzerland; (M.Z.); (M.W.)
| | - Gebhard F. X. Schertler
- Paul Scherrer Institute, Division of Biology and Chemistry (BIO), PSI, Forschungsstrasse 111, 5232 Villigen, Switzerland;
| | - Philipp Berger
- Paul Scherrer Institute, Laboratory of Nanoscale Biology, PSI, Forschungsstrasse 111, 5232 Villigen, Switzerland; (M.S.); (L.T.); (B.M.)
- Correspondence: ; Tel.: +41-56-310-4728; Fax: +41-56-310-5288
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183
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Poc P, Gutzeit VA, Ast J, Lee J, Jones BJ, D'Este E, Mathes B, Lehmann M, Hodson DJ, Levitz J, Broichhagen J. Interrogating surface versus intracellular transmembrane receptor populations using cell-impermeable SNAP-tag substrates. Chem Sci 2020; 11:7871-7883. [PMID: 34123074 PMCID: PMC8163392 DOI: 10.1039/d0sc02794d] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/02/2020] [Indexed: 01/13/2023] Open
Abstract
Employing self-labelling protein tags for the attachment of fluorescent dyes has become a routine and powerful technique in optical microscopy to visualize and track fused proteins. However, membrane permeability of the dyes and the associated background signals can interfere with the analysis of extracellular labelling sites. Here we describe a novel approach to improve extracellular labelling by functionalizing the SNAP-tag substrate benzyl guanine ("BG") with a charged sulfonate ("SBG"). This chemical manipulation can be applied to any SNAP-tag substrate, improves solubility, reduces non-specific staining and renders the bioconjugation handle impermeable while leaving its cargo untouched. We report SBG-conjugated fluorophores across the visible spectrum, which cleanly label SNAP-fused proteins in the plasma membrane of living cells. We demonstrate the utility of SBG-conjugated fluorophores to interrogate class A, B and C G protein-coupled receptors (GPCRs) using a range of imaging approaches including nanoscopic superresolution imaging, analysis of GPCR trafficking from intra- and extracellular pools, in vivo labelling in mouse brain and analysis of receptor stoichiometry using single molecule pull down.
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Affiliation(s)
- Pascal Poc
- Max Planck Institute for Medical Research, Department of Chemical Biology Jahnstr. 29 69120 Heidelberg Germany
| | - Vanessa A Gutzeit
- Neuroscience Graduate Program, Weill Cornell Medicine New York NY 10065 USA
| | - Julia Ast
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham Birmingham UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners Birmingham UK
| | - Joon Lee
- Department of Biochemistry, Weill Cornell Medicine New York NY 10065 USA
| | - Ben J Jones
- Section of Investigative Medicine, Imperial College London London W12 0NN UK
| | - Elisa D'Este
- Optical Microscopy Facility, Max Planck Institute for Medical Research Heidelberg Germany
| | - Bettina Mathes
- Max Planck Institute for Medical Research, Department of Chemical Biology Jahnstr. 29 69120 Heidelberg Germany
| | - Martin Lehmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Department of Pharmacology and Cell Biology Robert-Rössle-Str. 10 13125 Berlin Germany
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham Birmingham UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners Birmingham UK
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine New York NY 10065 USA
- Tri-Institutional PhD Program in Chemical Biology New York NY 10065 USA
| | - Johannes Broichhagen
- Max Planck Institute for Medical Research, Department of Chemical Biology Jahnstr. 29 69120 Heidelberg Germany
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Department of Chemical Biology Robert-Rössle-Str. 10 13125 Berlin Germany
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184
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Ghosh E, Dwivedi H, Baidya M, Srivastava A, Kumari P, Stepniewski T, Kim HR, Lee MH, van Gastel J, Chaturvedi M, Roy D, Pandey S, Maharana J, Guixà-González R, Luttrell LM, Chung KY, Dutta S, Selent J, Shukla AK. Conformational Sensors and Domain Swapping Reveal Structural and Functional Differences between β-Arrestin Isoforms. Cell Rep 2020; 28:3287-3299.e6. [PMID: 31553900 DOI: 10.1016/j.celrep.2019.08.053] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/05/2019] [Accepted: 08/16/2019] [Indexed: 02/08/2023] Open
Abstract
Desensitization, signaling, and trafficking of G-protein-coupled receptors (GPCRs) are critically regulated by multifunctional adaptor proteins, β-arrestins (βarrs). The two isoforms of βarrs (βarr1 and 2) share a high degree of sequence and structural similarity; still, however, they often mediate distinct functional outcomes in the context of GPCR signaling and regulation. A mechanistic basis for such a functional divergence of βarr isoforms is still lacking. By using a set of complementary approaches, including antibody-fragment-based conformational sensors, we discover structural differences between βarr1 and 2 upon their interaction with activated and phosphorylated receptors. Interestingly, domain-swapped chimeras of βarrs display robust complementation in functional assays, thereby linking the structural differences between receptor-bound βarr1 and 2 with their divergent functional outcomes. Our findings reveal important insights into the ability of βarr isoforms to drive distinct functional outcomes and underscore the importance of integrating this aspect in the current framework of biased agonism.
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Affiliation(s)
- Eshan Ghosh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Hemlata Dwivedi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Mithu Baidya
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Ashish Srivastava
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Punita Kumari
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Tomek Stepniewski
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain
| | - Hee Ryung Kim
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, South Korea
| | - Mi-Hye Lee
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Jaana van Gastel
- Translational Neurobiology Group, Center of Molecular Neurology, VIB, Antwerp, Belgium; Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Madhu Chaturvedi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Debarati Roy
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Shubhi Pandey
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Jagannath Maharana
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Ramon Guixà-González
- Laboratory of Computational Medicine, Biostatistics Unit, Faculty of Medicine, Autonomous University of Barcelona, 08193 Bellaterra, Spain
| | - Louis M Luttrell
- Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA; Research Service of the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401, USA
| | - Ka Young Chung
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, South Korea
| | - Somnath Dutta
- Molecular Biophysics Unit, Indian Institute of Sciences, Bangalore, India
| | - Jana Selent
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), 08003 Barcelona, Spain
| | - Arun K Shukla
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
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185
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Mechanism of β-arrestin recruitment by the μ-opioid G protein-coupled receptor. Proc Natl Acad Sci U S A 2020; 117:16346-16355. [PMID: 32601232 DOI: 10.1073/pnas.1918264117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Agonists to the μ-opioid G protein-coupled receptor (μOR) can alleviate pain through activation of G protein signaling, but they can also induce β-arrestin activation, leading to such side effects as respiratory depression. Biased ligands to μOR that induce G protein signaling without inducing β-arrestin signaling can alleviate pain while reducing side effects. However, the mechanism for stimulating β-arrestin signaling is not known, making it difficult to design optimum biased ligands. We use extensive molecular dynamics simulations to determine three-dimensional (3D) structures of activated β-arrestin2 stabilized by phosphorylated μOR bound to the morphine and D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO) nonbiased agonists and to the TRV130 biased agonist. For nonbiased agonists, we find that the β-arrestin2 couples to the phosphorylated μOR by forming strong polar interactions with intracellular loop 2 (ICL2) and either the ICL3 or cytoplasmic region of transmembrane (TM6). Strikingly, Gi protein makes identical strong bonds with these same ICLs. Thus, the Gi protein and β-arrestin2 compete for the same binding site even though their recruitment leads to much different outcomes. On the other hand, we find that TRV130 has a greater tendency to bind the extracellular portion of TM2 and TM3, which repositions TM6 in the cytoplasmic region of μOR, hindering β-arrestin2 from making polar anchors to the ICL3 or to the cytosolic end of TM6. This dramatically reduces the affinity between μOR and β-arrestin2.
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186
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Kaya AI, Perry NA, Gurevich VV, Iverson TM. Phosphorylation barcode-dependent signal bias of the dopamine D1 receptor. Proc Natl Acad Sci U S A 2020; 117:14139-14149. [PMID: 32503917 PMCID: PMC7321966 DOI: 10.1073/pnas.1918736117] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Agonist-activated G protein-coupled receptors (GPCRs) must correctly select from hundreds of potential downstream signaling cascades and effectors. To accomplish this, GPCRs first bind to an intermediary signaling protein, such as G protein or arrestin. These intermediaries initiate signaling cascades that promote the activity of different effectors, including several protein kinases. The relative roles of G proteins versus arrestins in initiating and directing signaling is hotly debated, and it remains unclear how the correct final signaling pathway is chosen given the ready availability of protein partners. Here, we begin to deconvolute the process of signal bias from the dopamine D1 receptor (D1R) by exploring factors that promote the activation of ERK1/2 or Src, the kinases that lead to cell growth and proliferation. We found that ERK1/2 activation involves both arrestin and Gαs, while Src activation depends solely on arrestin. Interestingly, we found that the phosphorylation pattern influences both arrestin and Gαs coupling, suggesting an additional way the cells regulate G protein signaling. The phosphorylation sites in the D1R intracellular loop 3 are particularly important for directing the binding of G protein versus arrestin and for selecting between the activation of ERK1/2 and Src. Collectively, these studies correlate functional outcomes with a physical basis for signaling bias and provide fundamental information on how GPCR signaling is directed.
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Affiliation(s)
- Ali I Kaya
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232
| | - Nicole A Perry
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232
| | | | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232;
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
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187
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Min K, Yoon HJ, Park JY, Baidya M, Dwivedi-Agnihotri H, Maharana J, Chaturvedi M, Chung KY, Shukla AK, Lee HH. Crystal Structure of β-Arrestin 2 in Complex with CXCR7 Phosphopeptide. Structure 2020; 28:1014-1023.e4. [PMID: 32579945 DOI: 10.1016/j.str.2020.06.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 04/02/2020] [Accepted: 06/03/2020] [Indexed: 12/21/2022]
Abstract
β-Arrestins (βarrs) critically regulate G-protein-coupled receptor (GPCR) signaling and trafficking. βarrs have two isoforms, βarr1 and βarr2. Receptor phosphorylation is a key determinant for the binding of βarrs, and understanding the intricate details of receptor-βarr interaction is the next frontier in GPCR structural biology. The high-resolution structure of active βarr1 in complex with a phosphopeptide derived from GPCR has been revealed, but that of βarr2 remains elusive. Here, we present a 2.3-Å crystal structure of βarr2 in complex with a phosphopeptide (C7pp) derived from the carboxyl terminus of CXCR7. The structural analysis of C7pp-bound βarr2 reveals key differences from the previously determined active conformation of βarr1. One of the key differences is that C7pp-bound βarr2 shows a relatively small inter-domain rotation. Antibody-fragment-based conformational sensor and hydrogen/deuterium exchange experiments further corroborated the structural features of βarr2 and suggested that βarr2 adopts a range of inter-domain rotations.
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Affiliation(s)
- Kyungjin Min
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Hye-Jin Yoon
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Ji Young Park
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Mithu Baidya
- Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | | | - Jagannath Maharana
- Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Madhu Chaturvedi
- Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Ka Young Chung
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea.
| | - Arun K Shukla
- Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
| | - Hyung Ho Lee
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea.
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188
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Sutkeviciute I, Vilardaga JP. Structural insights into emergent signaling modes of G protein-coupled receptors. J Biol Chem 2020; 295:11626-11642. [PMID: 32571882 DOI: 10.1074/jbc.rev120.009348] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 06/21/2020] [Indexed: 12/21/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent the largest family of cell membrane proteins, with >800 GPCRs in humans alone, and recognize highly diverse ligands, ranging from photons to large protein molecules. Very important to human medicine, GPCRs are targeted by about 35% of prescription drugs. GPCRs are characterized by a seven-transmembrane α-helical structure, transmitting extracellular signals into cells to regulate major physiological processes via heterotrimeric G proteins and β-arrestins. Initially viewed as receptors whose signaling via G proteins is delimited to the plasma membrane, it is now recognized that GPCRs signal also at various intracellular locations, and the mechanisms and (patho)physiological relevance of such signaling modes are actively investigated. The propensity of GPCRs to adopt different signaling modes is largely encoded in the structural plasticity of the receptors themselves and of their signaling complexes. Here, we review emerging modes of GPCR signaling via endosomal membranes and the physiological implications of such signaling modes. We further summarize recent structural insights into mechanisms of GPCR activation and signaling. We particularly emphasize the structural mechanisms governing the continued GPCR signaling from endosomes and the structural aspects of the GPCR resensitization mechanism and discuss the recently uncovered and important roles of lipids in these processes.
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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, Pennsylvania, USA
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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189
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The Glycosphingolipid GM3 Modulates Conformational Dynamics of the Glucagon Receptor. Biophys J 2020; 119:300-313. [PMID: 32610088 PMCID: PMC7376093 DOI: 10.1016/j.bpj.2020.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/27/2020] [Accepted: 06/09/2020] [Indexed: 12/12/2022] Open
Abstract
The extracellular domain (ECD) of class B1 G-protein-coupled receptors (GPCRs) plays a central role in signal transduction and is uniquely positioned to sense both the extracellular and membrane environments. Although recent studies suggest a role for membrane lipids in the modulation of class A and class F GPCR signaling properties, little is known about the effect of lipids on class B1 receptors. In this study, we employed multiscale molecular dynamics simulations to access the dynamics of the glucagon receptor (GCGR) ECD in the presence of native-like membrane bilayers. Simulations showed that the ECD could move about a hinge region formed by residues Q122–E126 to adopt both closed and open conformations relative to the transmembrane domain. ECD movements were modulated by binding of the glycosphingolipid GM3. These large-scale fluctuations in ECD conformation may affect the ligand binding and receptor activation properties. We also identify a unique phosphatidylinositol (4,5)-bisphosphate (PIP2) interaction profile near intracellular loop (ICL) 2/TM3 at the G-protein-coupling interface, suggesting a mechanism of engaging G-proteins that may have a distinct dependence on PIP2 compared with class A GPCRs. Given the structural conservation of class B1 GPCRs, the modulatory effects of GM3 and PIP2 on GCGR may be conserved across these receptors, offering new insights into potential therapeutic targeting.
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190
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Lazar AM, Irannejad R, Baldwin TA, Sundaram AB, Gutkind JS, Inoue A, Dessauer CW, Von Zastrow M. G protein-regulated endocytic trafficking of adenylyl cyclase type 9. eLife 2020; 9:e58039. [PMID: 32515353 PMCID: PMC7332294 DOI: 10.7554/elife.58039] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/08/2020] [Indexed: 12/14/2022] Open
Abstract
GPCRs are increasingly recognized to initiate signaling via heterotrimeric G proteins as they move through the endocytic network, but little is known about how relevant G protein effectors are localized. Here we report selective trafficking of adenylyl cyclase type 9 (AC9) from the plasma membrane to endosomes while adenylyl cyclase type 1 (AC1) remains in the plasma membrane, and stimulation of AC9 trafficking by ligand-induced activation of Gs-coupled GPCRs. AC9 transits a similar, dynamin-dependent early endocytic pathway as ligand-activated GPCRs. However, unlike GPCR traffic control which requires β-arrestin but not Gs, AC9 traffic control requires Gs but not β-arrestin. We also show that AC9, but not AC1, mediates cAMP production stimulated by endogenous receptor activation in endosomes. These results reveal dynamic and isoform-specific trafficking of adenylyl cyclase in the endocytic network, and a discrete role of a heterotrimeric G protein in regulating the subcellular distribution of a relevant effector.
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Affiliation(s)
- André M Lazar
- Program in Biochemistry and Cell Biology, University of California San FranciscoSan FranciscoUnited States
| | - Roshanak Irannejad
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
| | - Tanya A Baldwin
- Department of Integrative Biology and Pharmacology, University of Texas Health Science CenterHoustonUnited States
| | - Aparna B Sundaram
- Lung Biology Center, Department of Medicine, University of California San FranciscoSan FranciscoUnited States
| | - J Silvio Gutkind
- Department of Pharmacology and Moores Cancer Center, University of California San DiegoSan DiegoUnited States
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-kuSendaiJapan
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, University of Texas Health Science CenterHoustonUnited States
| | - Mark Von Zastrow
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Department of Psychiatry and Department of Cellular and Molecular Pharmacology, University of California San FranciscoSan FranciscoUnited States
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191
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Vezzi V, Ambrosio C, Grò MC, Molinari P, Süral G, Costa T, Onaran HO, Cotecchia S. Vasopressin receptor 2 mutations in the nephrogenic syndrome of inappropriate antidiuresis show different mechanisms of constitutive activation for G protein coupled receptors. Sci Rep 2020; 10:9111. [PMID: 32499611 PMCID: PMC7272623 DOI: 10.1038/s41598-020-65996-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 05/13/2020] [Indexed: 01/14/2023] Open
Abstract
Vasopressin receptor 2 (V2R) mutations causing the nephrogenic syndrome of inappropriate antidiuresis (NSIAD) can generate two constitutively active receptor phenotypes. One type results from residue substitutions in several V2R domains and is sensitive to vaptan inverse agonists. The other is only caused by Arg 137 replacements and is vaptan resistant. We compared constitutive and agonist-driven interactions of the vaptan-sensitive F229V and vaptan-resistant R137C/L V2R mutations with β-arrestin 1, β-arrestin 2, and Gαs, using null fibroblasts reconstituted with individual versions of the ablated transduction protein genes. F229V displayed very high level of constitutive activation for Gs but not for β-arrestins, and enhanced or normal responsiveness to agonists and inverse agonists. In contrast, R137C/L mutants exhibited maximal levels of constitutive activation for βarrestin 2 and Gs, minimal levels for β-arrestin 1, but a sharp decline of ligands sensitivity at all transducer interactions. The enhanced constitutive activity and reduced ligand sensitivity of R137 mutants on cAMP signaling persisted in cells lacking β-arrestins, indicating that these are intrinsic molecular properties of the mutations, not the consequence of altered receptor trafficking. The results suggest that the two groups of NSIAD mutations represent two distinct molecular mechanisms of constitutive activation in GPCRs.
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Affiliation(s)
- Vanessa Vezzi
- Istituto Superiore di Sanitá, National Center for Drug Research and Evaluation, Rome, Italy
| | - Caterina Ambrosio
- Istituto Superiore di Sanitá, National Center for Drug Research and Evaluation, Rome, Italy
| | - Maria Cristina Grò
- Istituto Superiore di Sanitá, National Center for Drug Research and Evaluation, Rome, Italy
| | - Paola Molinari
- Istituto Superiore di Sanitá, National Center for Drug Research and Evaluation, Rome, Italy
| | - Gökçe Süral
- Ankara University, Faculty of Medicine, Department of Pharmacology, Molecular biology and Technology development unit, Sıhhiye, Ankara, Turkey
| | - Tommaso Costa
- Istituto Superiore di Sanitá, National Center for Drug Research and Evaluation, Rome, Italy
| | - H Ongun Onaran
- Ankara University, Faculty of Medicine, Department of Pharmacology, Molecular biology and Technology development unit, Sıhhiye, Ankara, Turkey
| | - Susanna Cotecchia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125, Bari, Italy.
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192
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Rao BD, Sarkar P, Chattopadhyay A. Selectivity in agonist and antagonist binding to Serotonin 1A receptors via G-protein coupling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183265. [PMID: 32156647 DOI: 10.1016/j.bbamem.2020.183265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 12/16/2022]
Abstract
G protein-coupled receptors (GPCRs) constitute the largest superfamily of membrane proteins in higher eukaryotes, and facilitate information transfer from the extracellular environment to the cellular interior upon activation by ligands. Their role in diverse signaling processes makes them an attractive choice as drug targets. GPCRs are coupled to heterotrimeric G-proteins which represent an important interface through which signal transduction occurs across the plasma membrane upon activation by ligands. To obtain further insight into the molecular details of interaction of G-proteins with GPCRs, in this work, we explored the selectivity of binding of specific agonists and antagonists to the serotonin1A receptor under conditions of progressive G-protein inactivation. The serotonin1A receptor is an important neurotransmitter receptor belonging to the GPCR family and is a popular drug target. By use of a number of agents to inactivate G-proteins, we show here that the serotonin1A receptor displays differential discrimination between agonist and antagonist binding. Our results show a reduction in binding sites of the receptor upon treatment with G-protein inactivating agents. In addition, G-protein coupling efficiency was enhanced when G-proteins were inactivated using urea and alkaline pH. We envision that our results could be useful in achieving multiple signaling states of the receptor by fine tuning the conditions of G-protein inactivation and in structural biology of GPCRs bound to specific ligands.
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Affiliation(s)
- Bhagyashree D Rao
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India; CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India; Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India; Academy of Scientific and Innovative Research, Ghaziabad 201 002, India.
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193
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The β-arrestin-biased β-adrenergic receptor blocker carvedilol enhances skeletal muscle contractility. Proc Natl Acad Sci U S A 2020; 117:12435-12443. [PMID: 32414934 DOI: 10.1073/pnas.1920310117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A decrease in skeletal muscle strength and functional exercise capacity due to aging, frailty, and muscle wasting poses major unmet clinical needs. These conditions are associated with numerous adverse clinical outcomes including falls, fractures, and increased hospitalization. Clenbuterol, a β2-adrenergic receptor (β2AR) agonist enhances skeletal muscle strength and hypertrophy; however, its clinical utility is limited by side effects such as cardiac arrhythmias mediated by G protein signaling. We recently reported that clenbuterol-induced increases in contractility and skeletal muscle hypertrophy were lost in β-arrestin 1 knockout mice, implying that arrestins, multifunctional adapter and signaling proteins, play a vital role in mediating the skeletal muscle effects of β2AR agonists. Carvedilol, classically defined as a βAR antagonist, is widely used for the treatment of chronic systolic heart failure and hypertension, and has been demonstrated to function as a β-arrestin-biased ligand for the β2AR, stimulating β-arrestin-dependent but not G protein-dependent signaling. In this study, we investigated whether treatment with carvedilol could enhance skeletal muscle strength via β-arrestin-dependent pathways. In a murine model, we demonstrate chronic treatment with carvedilol, but not other β-blockers, indeed enhances contractile force in skeletal muscle and this is mediated by β-arrestin 1. Interestingly, carvedilol enhanced skeletal muscle contractility despite a lack of effect on skeletal muscle hypertrophy. Our findings suggest a potential unique clinical role of carvedilol to stimulate skeletal muscle contractility while avoiding the adverse effects with βAR agonists. This distinctive signaling profile could present an innovative approach to treating sarcopenia, frailty, and secondary muscle wasting.
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194
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Sussman CR, Wang X, Chebib FT, Torres VE. Modulation of polycystic kidney disease by G-protein coupled receptors and cyclic AMP signaling. Cell Signal 2020; 72:109649. [PMID: 32335259 DOI: 10.1016/j.cellsig.2020.109649] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022]
Abstract
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a systemic disorder associated with polycystic liver disease (PLD) and other extrarenal manifestations, the most common monogenic cause of end-stage kidney disease, and a major burden for public health. Many studies have shown that alterations in G-protein and cAMP signaling play a central role in its pathogenesis. As for many other diseases (35% of all approved drugs target G-protein coupled receptors (GPCRs) or proteins functioning upstream or downstream from GPCRs), treatments targeting GPCR have shown effectiveness in slowing the rate of progression of ADPKD. Tolvaptan, a vasopressin V2 receptor antagonist is the first drug approved by regulatory agencies to treat rapidly progressive ADPKD. Long-acting somatostatin analogs have also been effective in slowing the rates of growth of polycystic kidneys and liver. Although no treatment has so far been able to prevent the development or stop the progression of the disease, these encouraging advances point to G-protein and cAMP signaling as a promising avenue of investigation that may lead to more effective and safe treatments. This will require a better understanding of the relevant GPCRs, G-proteins, cAMP effectors, and of the enzymes and A-kinase anchoring proteins controlling the compartmentalization of cAMP signaling. The purpose of this review is to provide an overview of general GPCR signaling; the function of polycystin-1 (PC1) as a putative atypical adhesion GPCR (aGPCR); the roles of PC1, polycystin-2 (PC2) and the PC1-PC2 complex in the regulation of calcium and cAMP signaling; the cross-talk of calcium and cAMP signaling in PKD; and GPCRs, adenylyl cyclases, cyclic nucleotide phosphodiesterases, and protein kinase A as therapeutic targets in ADPKD.
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Affiliation(s)
- Caroline R Sussman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Xiaofang Wang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Fouad T Chebib
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Vicente E Torres
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America.
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195
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Matti C, Salnikov A, Artinger M, D'Agostino G, Kindinger I, Uguccioni M, Thelen M, Legler DF. ACKR4 Recruits GRK3 Prior to β-Arrestins but Can Scavenge Chemokines in the Absence of β-Arrestins. Front Immunol 2020; 11:720. [PMID: 32391018 PMCID: PMC7188906 DOI: 10.3389/fimmu.2020.00720] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/30/2020] [Indexed: 01/14/2023] Open
Abstract
Chemokines are essential for guiding cell migration. Atypical chemokine receptors (ACKRs) contribute to the cell migration process by binding, internalizing and degrading local chemokines, which enables the formation of confined gradients. ACKRs are heptahelical membrane spanning molecules structurally related to G-protein coupled receptors (GPCRs), but seem to be unable to signal through G-proteins upon ligand binding. ACKR4 internalizes the chemokines CCL19, CCL21, and CCL25 and is best known for shaping functional CCL21 gradients. Ligand binding to ACKR4 has been shown to recruit β-arrestins that has led to the assumption that chemokine scavenging relies on β-arrestin-mediated ACKR4 trafficking, a common internalization route taken by class A GPCRs. Here, we show that CCL19, CCL21, and CCL25 readily recruited β-arrestin1 and β-arrestin2 to human ACKR4, but found no evidence for β-arrestin-dependent or independent ACKR4-mediated activation of the kinases Erk1/2, Akt, or Src. However, we demonstrate that β-arrestins interacted with ACKR4 in the steady-state and contributed to the spontaneous trafficking of the receptor in the absence of chemokines. Deleting the C-terminus of ACKR4 not only interfered with the interaction of β-arrestins, but also with the uptake of fluorescently labeled cognate chemokines. We identify the GPCR kinase GRK3, and to a lesser extent GRK2, but not GRK4, GRK5, and GRK6, to be recruited to chemokine-stimulated ACKR4. We show that GRK3 recruitment proceded the recruitment of β-arrestins upon ACKR4 engagement and that GRK2/3 inhibition partially interfered with steady-state interaction and chemokine-driven recruitment of β-arrestins to ACKR4. Overexpressing β-arrestin2 accelerated the uptake of fluorescently labeled CCL19, indicating that β-arrestins contribute to the chemokine scavenging activity of ACKR4. By contrast, cells lacking β-arrestins were still capable to take up fluorescently labeled CCL19 demonstrating that β-arrestins are dispensable for chemokine scavenging by ACKR4.
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Affiliation(s)
- Christoph Matti
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Angela Salnikov
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Marc Artinger
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Gianluca D'Agostino
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Ilona Kindinger
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Mariagrazia Uguccioni
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Marcus Thelen
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Daniel F Legler
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland.,Faculty of Biology, University of Konstanz, Konstanz, Germany.,Theodor Kocher Institute, University of Bern, Bern, Switzerland
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196
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Gong Z, Xiong L, Shi H, Yang S, Herrera-Estrella LR, Xu G, Chao DY, Li J, Wang PY, Qin F, Li J, Ding Y, Shi Y, Wang Y, Yang Y, Guo Y, Zhu JK. Plant abiotic stress response and nutrient use efficiency. SCIENCE CHINA-LIFE SCIENCES 2020; 63:635-674. [PMID: 32246404 DOI: 10.1007/s11427-020-1683-x] [Citation(s) in RCA: 531] [Impact Index Per Article: 132.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/17/2020] [Indexed: 12/15/2022]
Abstract
Abiotic stresses and soil nutrient limitations are major environmental conditions that reduce plant growth, productivity and quality. Plants have evolved mechanisms to perceive these environmental challenges, transmit the stress signals within cells as well as between cells and tissues, and make appropriate adjustments in their growth and development in order to survive and reproduce. In recent years, significant progress has been made on many fronts of the stress signaling research, particularly in understanding the downstream signaling events that culminate at the activation of stress- and nutrient limitation-responsive genes, cellular ion homeostasis, and growth adjustment. However, the revelation of the early events of stress signaling, particularly the identification of primary stress sensors, still lags behind. In this review, we summarize recent work on the genetic and molecular mechanisms of plant abiotic stress and nutrient limitation sensing and signaling and discuss new directions for future studies.
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Affiliation(s)
- Zhizhong Gong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Liming Xiong
- Department of Biology, Hong Kong Baptist University, Kowlong Tong, Hong Kong, China
| | - Huazhong Shi
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Shuhua Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Luis R Herrera-Estrella
- Plant and Soil Science Department (IGCAST), Texas Tech University, Lubbock, TX, 79409, USA.,Unidad de Genómica Avanzada (Langebio), Centro de Investigación y de Estudios Avanzados, Irapuato, 36610, México.,College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Guohua Xu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Dai-Yin Chao
- National Key laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jingrui Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Peng-Yun Wang
- School of Life Science, Henan University, Kaifeng, 457000, China
| | - Feng Qin
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jijang Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yanglin Ding
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yiting Shi
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yu Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yongqing Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yan Guo
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
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197
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Ziffert I, Kaiser A, Babilon S, Mörl K, Beck-Sickinger AG. Unusually persistent Gα i-signaling of the neuropeptide Y 2 receptor depletes cellular G i/o pools and leads to a G i-refractory state. Cell Commun Signal 2020; 18:49. [PMID: 32223755 PMCID: PMC7104545 DOI: 10.1186/s12964-020-00537-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 02/19/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND A sensitive balance between receptor activation and desensitization is crucial for cellular homeostasis. Like many other GPCR, the human neuropeptide Y2 receptor (hY2R) undergoes ligand dependent activation and internalization into intracellular compartments, followed by recycling to the plasma membrane. This receptor is involved in the pathophysiology of distinct diseases e.g. epilepsy and cancer progression and conveys anorexigenic signals which makes it an interesting and promising anti-obesity target. However, Y2R desensitization was observed after daily treatment with a selective PYY13-36 analog in vivo by a yet unknown mechanism. MATERIALS We studied the desensitization and activatability of recycled Y2R in transiently transfected HEK293 cells as well as in endogenously Y2R expressing SH-SY5Y and SMS-KAN cells. Results were evaluated by one-way ANOVA and Tukey post test. RESULTS We observed strong desensitization of the Y2R in a second round of stimulation despite its reappearance at the membrane. Already the first activation of the Y2R leads to depletion of the functional cellular Gαi/o protein pool and consequently desensitizes the linked signal transduction pathways, independent of receptor internalization. This desensitization also extends to other Gαi/o-coupled GPCR and can be detected in transfected HEK293 as well as in SH-SY5Y and SMS-KAN cell lines, both expressing the Y2R endogenously. By overexpression of chimeric Gαqi proteins in a model system, activation has been rescued, which identifies a critical role of the G protein status for cellular signaling. Furthermore, Y2R displays strong allosteric coupling to inhibitory G proteins in radioligand binding assays, and loses 10-fold affinity in the G protein-depleted state observed after activation, which can be largely abrogated by overexpression of the Gαi-subunit. CONCLUSION The unusually persistent Gαi-signaling of the Y2R leads to a state of cellular desensitization of the inhibitory Gαi-pathway. The strong allosteric effects of the Y2R-Gαi-interaction might be a mechanism that contributes to the burst of Gαi-signaling, but also serves as a mechanism to limit the Y2-mediated signaling after recycling. Thus, the cell is left in a refractory state, preventing further Gαi-signaling of the Y2R itself but also other Gαi/o-coupled receptors by simply controlling the repertoire of downstream effectors. Video abstract.
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Affiliation(s)
- Isabelle Ziffert
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany
| | - Anette Kaiser
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany
| | - Stefanie Babilon
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany
| | - Karin Mörl
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany
| | - Annette G Beck-Sickinger
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103, Leipzig, Germany.
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198
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Biased GPCR signaling: Possible mechanisms and inherent limitations. Pharmacol Ther 2020; 211:107540. [PMID: 32201315 DOI: 10.1016/j.pharmthera.2020.107540] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/17/2020] [Indexed: 02/06/2023]
Abstract
G protein-coupled receptors (GPCRs) are targeted by about a third of clinically used drugs. Many GPCRs couple to more than one type of heterotrimeric G proteins, become phosphorylated by any of several different GRKs, and then bind one or more types of arrestin. Thus, classical therapeutically active drugs simultaneously initiate several branches of signaling, some of which are beneficial, whereas others result in unwanted on-target side effects. The development of novel compounds to selectively channel the signaling into the desired direction has the potential to become a breakthrough in health care. However, there are natural and technological hurdles that must be overcome. The fact that most GPCRs are subject to homologous desensitization, where the active receptor couples to G proteins, is phosphorylated by GRKs, and then binds arrestins, suggest that in most cases the GPCR conformations that facilitate their interactions with these three classes of binding partners significantly overlap. Thus, while partner-specific conformations might exist, they are likely low-probability states. GPCRs are inherently flexible, which suggests that complete bias is highly unlikely to be feasible: in the conformational ensemble induced by any ligand, there would be some conformations facilitating receptor coupling to unwanted partners. Things are further complicated by the fact that virtually every cell expresses numerous G proteins, several GRK subtypes, and two non-visual arrestins with distinct signaling capabilities. Finally, novel screening methods for measuring ligand bias must be devised, as the existing methods are not specific for one particular branch of signaling.
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199
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van der Velden WJC, Heitman LH, Rosenkilde MM. Perspective: Implications of Ligand-Receptor Binding Kinetics for Therapeutic Targeting of G Protein-Coupled Receptors. ACS Pharmacol Transl Sci 2020; 3:179-189. [PMID: 32296761 DOI: 10.1021/acsptsci.0c00012] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Indexed: 12/16/2022]
Abstract
The concept of ligand-receptor binding kinetics has been broadly applied in drug development pipelines focusing on G protein-coupled receptors (GPCRs). The ligand residence time (RT) for a receptor describes how long a ligand-receptor complex exists, and is defined as the reciprocal of the dissociation rate constant (k off). RT has turned out to be a valuable parameter for GPCR researchers focusing on drug development as a good predictor of in vivo efficacy. The positive correlation between RT and in vivo efficacy has been established for several drugs targeting class A GPCRs (e.g., the neurokinin-1 receptor (NK1R), the β2 adrenergic receptor (β2AR), and the muscarinic 3 receptor (M3R)) and for drugs targeting class B1 (e.g., the glucagon-like peptide 1 receptor (GLP-1R)). Recently, the association rate constant (k on) has gained similar attention as another parameter affecting in vivo efficacy. In the current perspective, we address the importance of studying ligand-receptor binding kinetics for therapeutic targeting of GPCRs, with an emphasis on how binding kinetics can be altered by subtle molecular changes in the ligands and/or the receptors and how such changes affect treatment outcome. Moreover, we speculate on the impact of binding kinetic parameters for functional selectivity and sustained receptor signaling from endosomal compartments; phenomena that have gained increasing interest in attempts to improve therapeutic targeting of GPCRs.
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Affiliation(s)
- Wijnand J C van der Velden
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK 2200, Denmark
| | - Laura H Heitman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden 2333 CC, The Netherlands
| | - Mette M Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK 2200, Denmark
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200
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Stoeber M, Jullié D, Li J, Chakraborty S, Majumdar S, Lambert NA, Manglik A, von Zastrow M. Agonist-selective recruitment of engineered protein probes and of GRK2 by opioid receptors in living cells. eLife 2020; 9:54208. [PMID: 32096468 PMCID: PMC7041944 DOI: 10.7554/elife.54208] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/29/2020] [Indexed: 12/21/2022] Open
Abstract
G protein-coupled receptors (GPCRs) signal through allostery, and it is increasingly clear that chemically distinct agonists can produce different receptor-based effects. It has been proposed that agonists selectively promote receptors to recruit one cellular interacting partner over another, introducing allosteric ‘bias’ into the signaling system. However, the underlying hypothesis - that different agonists drive GPCRs to engage different cytoplasmic proteins in living cells - remains untested due to the complexity of readouts through which receptor-proximal interactions are typically inferred. We describe a cell-based assay to overcome this challenge, based on GPCR-interacting biosensors that are disconnected from endogenous transduction mechanisms. Focusing on opioid receptors, we directly demonstrate differences between biosensor recruitment produced by chemically distinct opioid ligands in living cells. We then show that selective recruitment applies to GRK2, a biologically relevant GPCR regulator, through discrete interactions of GRK2 with receptors or with G protein beta-gamma subunits which are differentially promoted by agonists. About a third of all drugs work by targeting a group of proteins known as G-protein coupled receptors, or GPCRs for short. These receptors are found on the surface of cells and transmit messages across the cell’s outer barrier. When a signaling molecule, like a hormone, is released in the body, it binds to a GPCR and changes the receptor’s shape. The change in structure affects how the GPCR interacts and binds to other proteins on the inside of the cell, triggering a series of reactions that alter the cell’s activity. Scientists have previously seen that a GPCR can trigger different responses depending on which signaling molecule is binding on the surface of the cell. However, the mechanism for this is unknown. One hypothesis is that different signaling molecules change the GPCR’s preference for binding to different proteins on the inside of the cell. The challenge has been to observe this happening without interfering with the process. Stoeber et al. have now tested this idea by attaching fluorescent tags to proteins that bind to activated GPCRs directly and without binding other signaling proteins. This meant these proteins could be tracked under a microscope as they made their way to bind to the GPCRs. Stoeber et al. focused on one particular GPCR, known as the opioid receptor, and tested the binding of two different opioid signaling molecules, etorphine and Dynorphin A. The experiments revealed that the different opioids did affect which of the engineered proteins would preferentially bind to the opioid receptor. This was followed by a similar experiment, where the engineered proteins were replaced with another protein called GRK2, which binds to the opioid receptor under normal conditions in the cell. This showed that GRK2 binds much more strongly to the opioid receptor when Dynorphin A is added compared to adding etorphine. These findings show that GPCRs can not only communicate that a signaling molecule is binding but can respond differently to convey what molecule it is more specifically. This could be important in developing drugs, particularly to specifically trigger the desired response and reduce side effects. Stoeber et al. suggest that an important next step for research is to understand how the GPCRs preferentially bind to different proteins.
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Affiliation(s)
- Miriam Stoeber
- Department of Psychiatry, University of California, San Francisco, San Francisco, United States.,Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Damien Jullié
- Department of Psychiatry, University of California, San Francisco, San Francisco, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Joy Li
- Department of Psychiatry, University of California, San Francisco, San Francisco, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Soumen Chakraborty
- Center for Clinical Pharmacology, Washington University School of Medicine, St. Louis, United States.,St Louis College of Pharmacy, St. Louis, United States
| | - Susruta Majumdar
- Center for Clinical Pharmacology, Washington University School of Medicine, St. Louis, United States.,St Louis College of Pharmacy, St. Louis, United States
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, United States
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,Department of Anesthesia, University of California, San Francisco, San Francisco, United States
| | - Mark von Zastrow
- Department of Psychiatry, University of California, San Francisco, San Francisco, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
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