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De Paus LV, An Y, Janssen APA, van den Berg RJBHN, Heitman LH, van der Stelt M. Discovery of a Photoaffinity Probe that Captures the Active Conformation of the Cannabinoid CB 2 Receptor. Chembiochem 2024; 25:e202300785. [PMID: 38372466 DOI: 10.1002/cbic.202300785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/26/2024] [Accepted: 02/13/2024] [Indexed: 02/20/2024]
Abstract
The cannabinoid receptor type 2 (CB2R) is a G protein-coupled receptor with therapeutic potential for the treatment of inflammatory disorders. Fluorescent probes are desirable to study its receptor localization, expression and occupancy. Previously, we have reported a photoaffinity probe LEI-121 that stabilized the inactive conformation of the CB2R. Here, we report the structure-based design of a novel bifunctional probe that captures the active conformation of the CB2R upon irradiation with light. An alkyne handle was incorporated to visualize the receptor using click-chemistry with fluorophore-azides. These probes may hold promise to study different receptor conformations in relation to their cellular localization and function.
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Affiliation(s)
- Laura V De Paus
- Molecular Physiology, Leiden University, Einsteinweg 55, Leiden, The Netherlands
| | - Yu An
- Molecular Physiology, Leiden University, Einsteinweg 55, Leiden, The Netherlands
| | - Antonius P A Janssen
- Molecular Physiology, Leiden University, Einsteinweg 55, Leiden, The Netherlands
| | | | - Laura H Heitman
- Molecular Pharmacology, Leiden University, Einsteinweg 55, Leiden, The Netherlands
| | - Mario van der Stelt
- Molecular Physiology, Leiden University, Einsteinweg 55, Leiden, The Netherlands
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2
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Janicot R, Maziarz M, Park JC, Zhao J, Luebbers A, Green E, Philibert CE, Zhang H, Layne MD, Wu JC, Garcia-Marcos M. Direct interrogation of context-dependent GPCR activity with a universal biosensor platform. Cell 2024; 187:1527-1546.e25. [PMID: 38412860 PMCID: PMC10947893 DOI: 10.1016/j.cell.2024.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 12/04/2023] [Accepted: 01/18/2024] [Indexed: 02/29/2024]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of druggable proteins encoded in the human genome, but progress in understanding and targeting them is hindered by the lack of tools to reliably measure their nuanced behavior in physiologically relevant contexts. Here, we developed a collection of compact ONE vector G-protein Optical (ONE-GO) biosensor constructs as a scalable platform that can be conveniently deployed to measure G-protein activation by virtually any GPCR with high fidelity even when expressed endogenously in primary cells. By characterizing dozens of GPCRs across many cell types like primary cardiovascular cells or neurons, we revealed insights into the molecular basis for G-protein coupling selectivity of GPCRs, pharmacogenomic profiles of anti-psychotics on naturally occurring GPCR variants, and G-protein subtype signaling bias by endogenous GPCRs depending on cell type or upon inducing disease-like states. In summary, this open-source platform makes the direct interrogation of context-dependent GPCR activity broadly accessible.
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Affiliation(s)
- Remi Janicot
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Marcin Maziarz
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Jong-Chan Park
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Jingyi Zhao
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Alex Luebbers
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Elena Green
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Clementine Eva Philibert
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Hao Zhang
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mathew D Layne
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mikel Garcia-Marcos
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA; Department of Biology, College of Arts & Sciences, Boston University, Boston, MA 02115, USA.
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3
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Biswas I, Giri H, Panicker SR, Rezaie AR. Thrombomodulin Switches Signaling and Protease-Activated Receptor 1 Cleavage Specificity of Thrombin. Arterioscler Thromb Vasc Biol 2024; 44:603-616. [PMID: 38174561 PMCID: PMC10922642 DOI: 10.1161/atvbaha.123.320185] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024]
Abstract
BACKGROUND Cleavage of the extracellular domain of PAR1 (protease-activated receptor 1) by thrombin at Arg41 and by APC (activated protein C) at Arg46 initiates paradoxical cytopathic and cytoprotective signaling in endothelial cells. In the latter case, the ligand-dependent coreceptor signaling by EPCR (endothelial protein C receptor) is required for the protective PAR1 signaling by APC. Here, we investigated the role of thrombomodulin in determining the specificity of PAR1 signaling by thrombin. METHODS We prepared a PAR1 knockout (PAR1-/-) EA.hy926 endothelial cell line by CRISPR/Cas9 and transduced PAR1-/- cells with lentivirus vectors expressing PAR1 mutants in which either Arg41 or Arg46 was replaced with an Ala. Furthermore, human embryonic kidney 293 cells were transfected with wild-type or mutant PAR1 cleavage reporter constructs carrying N-terminal Nluc (NanoLuc luciferase) and C-terminal enhanced yellow fluorescent protein tags. RESULTS Characterization of transfected cells in signaling and receptor cleavage assays revealed that, upon interaction with thrombomodulin, thrombin cleaves Arg46 to elicit cytoprotective effects by a β-arrestin-2 biased signaling mechanism. Analysis of functional data and cleavage rates indicated that thrombin-thrombomodulin cleaves Arg46>10-fold faster than APC. Upon interaction with thrombin, the cytoplasmic domain of thrombomodulin recruited both β-arrestin-1 and -2 to the plasma membrane. Thus, the thrombin cleavage of Arg41 was also cytoprotective in thrombomodulin-expressing cells by β-arrestin-1-biased signaling. APC in the absence of EPCR cleaved Arg41 to initiate disruptive signaling responses like thrombin. CONCLUSIONS These results suggest that coreceptor signaling by thrombomodulin and EPCR determines the PAR1 cleavage and signaling specificity of thrombin and APC, respectively.
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Affiliation(s)
- Indranil Biswas
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation
| | - Hemant Giri
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation
| | - Sumith R. Panicker
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation
| | - Alireza R. Rezaie
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
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4
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Janicot R, Maziarz M, Park JC, Luebbers A, Green E, Zhao J, Philibert C, Zhang H, Layne MD, Wu JC, Garcia-Marcos M. Direct interrogation of context-dependent GPCR activity with a universal biosensor platform. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.02.573921. [PMID: 38260348 PMCID: PMC10802303 DOI: 10.1101/2024.01.02.573921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of druggable proteins in the human genome, but progress in understanding and targeting them is hindered by the lack of tools to reliably measure their nuanced behavior in physiologically-relevant contexts. Here, we developed a collection of compact ONE vector G-protein Optical (ONE-GO) biosensor constructs as a scalable platform that can be conveniently deployed to measure G-protein activation by virtually any GPCR with high fidelity even when expressed endogenously in primary cells. By characterizing dozens of GPCRs across many cell types like primary cardiovascular cells or neurons, we revealed new insights into the molecular basis for G-protein coupling selectivity of GPCRs, pharmacogenomic profiles of anti-psychotics on naturally-occurring GPCR variants, and G-protein subtype signaling bias by endogenous GPCRs depending on cell type or upon inducing disease-like states. In summary, this open-source platform makes the direct interrogation of context-dependent GPCR activity broadly accessible.
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Affiliation(s)
- Remi Janicot
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Marcin Maziarz
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Jong-Chan Park
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Alex Luebbers
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Elena Green
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Jingyi Zhao
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Clementine Philibert
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Hao Zhang
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mathew D. Layne
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Joseph C. Wu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mikel Garcia-Marcos
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
- Department of Biology, College of Arts & Sciences, Boston University, Boston, MA 02115, USA
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5
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Bernauer H, Schlör A, Maier J, Bannert N, Hanack K, Ivanusic D. tANCHOR fast and cost-effective cell-based immunization approach with focus on the receptor-binding domain of SARS-CoV-2. Biol Methods Protoc 2023; 8:bpad030. [PMID: 38090673 PMCID: PMC10713279 DOI: 10.1093/biomethods/bpad030] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/22/2023] [Accepted: 11/06/2023] [Indexed: 06/29/2024] Open
Abstract
Successful induction of antibodies in model organisms like mice depends strongly on antigen design and delivery. New antigen designs for immunization are helpful for developing future therapeutic monoclonal antibodies (mAbs). One of the gold standards to induce antibodies in mice is to express and purify the antigen for vaccination. This is especially time-consuming when mAbs are needed rapidly. We closed this gap and used the display technology tetraspanin anchor to develop a reliable immunization technique without the need to purify the antigen. This technique is able to speed up the immunization step enormously and we have demonstrated that we were able to induce antibodies against different proteins with a focus on the receptor-binding domain of SARS-CoV-2 and the extracellular loop of canine cluster of differentiation 20 displayed on the surface of human cells.
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Affiliation(s)
| | - Anja Schlör
- new/era/mabs GmbH, Potsdam 14482, Germany
- Institute for Biology and Biochemistry, University of Potsdam, Potsdam 14476, Germany
| | - Josef Maier
- ATG:biosynthetics GmbH, Merzhausen 79249, Germany
| | | | - Katja Hanack
- new/era/mabs GmbH, Potsdam 14482, Germany
- Institute for Biology and Biochemistry, University of Potsdam, Potsdam 14476, Germany
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Scimone C, Alibrandi S, Donato L, De Gaetano GV, Fusco C, Nardella G, Castori M, Rinaldi C, Alafaci C, Germanò A, D'Angelo R, Sidoti A. Amplification of protease-activated receptors signaling in sporadic cerebral cavernous malformation endothelial cells. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119474. [PMID: 37030452 DOI: 10.1016/j.bbamcr.2023.119474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/13/2023] [Accepted: 03/30/2023] [Indexed: 04/10/2023]
Abstract
In the central nervous system, thrombin-mediated activation of protease-activated receptors (PARs) results in neuroinflammation and increased vascular permeability. These events have been linked to cancer and neurodegeneration. Endothelial cells (ECs) isolated from sporadic cerebral cavernous malformation (CCM) specimens showed dysregulation of genes involved in "thrombin-mediated PAR-1 activation" signaling. CCM is a vascular disease involving brain capillaries. In CCM, ECs show defective cell junctions. Oxidative stress and neuroinflammation play a key role in disease onset and progression. In order to confirm the possible role of thrombin pathway in sporadic CCM pathogenesis, we evaluated PARs expression in CCM-ECs. We found that sporadic CCM-ECs overexpress PAR1, PAR3 and PAR4, together with other coagulation factor encoding genes. Moreover, we investigated about expression of the three familial CCM genes (KRIT1, CCM2 and PDCD10) in human cerebral microvascular ECs, following thrombin exposure, as well as protein level. Thrombin exposure affects EC viability and results in dysregulation of CCM gene expression and, then, in decreased protein level. Our results confirm amplification of PAR pathway in CCM suggesting, for the first time, the possible role of PAR1-mediated thrombin signaling in sporadic CCM. Thrombin-mediated PARs over activation results in increased blood-brain barrier permeability due to loss of cell junction integrity and, in this context, also the three familial CCM genes may be involved.
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Affiliation(s)
- Concetta Scimone
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria 1, 98125 Messina, Italy; Department of Biomolecular Strategies, Genetics, Cutting-edge Therapies, I.E.ME.S.T., via Michele Miraglia 20, Palermo 90139, Italy
| | - Simona Alibrandi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria 1, 98125 Messina, Italy; Department of Biomolecular Strategies, Genetics, Cutting-edge Therapies, I.E.ME.S.T., via Michele Miraglia 20, Palermo 90139, Italy; Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, C.da Papardo-Sperone 31, 98100 Messina, Italy
| | - Luigi Donato
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria 1, 98125 Messina, Italy; Department of Biomolecular Strategies, Genetics, Cutting-edge Therapies, I.E.ME.S.T., via Michele Miraglia 20, Palermo 90139, Italy
| | | | - Carmela Fusco
- Division of Medical Genetics, Fondazione IRCCS-Casa Sollievo della Sofferenza, San Giovanni Rotondo, 71013 Foggia, Italy
| | - Grazia Nardella
- Division of Medical Genetics, Fondazione IRCCS-Casa Sollievo della Sofferenza, San Giovanni Rotondo, 71013 Foggia, Italy
| | - Marco Castori
- Division of Medical Genetics, Fondazione IRCCS-Casa Sollievo della Sofferenza, San Giovanni Rotondo, 71013 Foggia, Italy
| | - Carmela Rinaldi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria 1, 98125 Messina, Italy.
| | - Concetta Alafaci
- Neurosurgery Unit, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria 1, 98125 Messina, Italy
| | - Antonino Germanò
- Neurosurgery Unit, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria 1, 98125 Messina, Italy
| | - Rosalia D'Angelo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria 1, 98125 Messina, Italy; Department of Biomolecular Strategies, Genetics, Cutting-edge Therapies, I.E.ME.S.T., via Michele Miraglia 20, Palermo 90139, Italy
| | - Antonina Sidoti
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, via Consolare Valeria 1, 98125 Messina, Italy; Department of Biomolecular Strategies, Genetics, Cutting-edge Therapies, I.E.ME.S.T., via Michele Miraglia 20, Palermo 90139, Italy
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Lee-Rivera I, López E, López-Colomé AM. Diversification of PAR signaling through receptor crosstalk. Cell Mol Biol Lett 2022; 27:77. [PMID: 36088291 PMCID: PMC9463773 DOI: 10.1186/s11658-022-00382-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
Protease activated receptors (PARs) are among the first receptors shown to transactivate other receptors: noticeably, these interactions are not limited to members of the same family, but involve receptors as diverse as receptor kinases, prostanoid receptors, purinergic receptors and ionic channels among others. In this review, we will focus on the evidence for PAR interactions with members of their own family, as well as with other types of receptors. We will discuss recent evidence as well as what we consider as emerging areas to explore; from the signalling pathways triggered, to the physiological and pathological relevance of these interactions, since this additional level of molecular cross-talk between receptors and signaling pathways is only beginning to be explored and represents a novel mechanism providing diversity to receptor function and play important roles in physiology and disease.
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8
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Kubra KT, Uddin MA, Barabutis N. Tunicamycin Protects against LPS-Induced Lung Injury. Pharmaceuticals (Basel) 2022; 15:ph15020134. [PMID: 35215247 PMCID: PMC8876572 DOI: 10.3390/ph15020134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/16/2022] [Accepted: 01/21/2022] [Indexed: 12/29/2022] Open
Abstract
The pulmonary endothelium is a dynamic semipermeable barrier that orchestrates tissue-fluid homeostasis; regulating physiological and immunological responses. Endothelial abnormalities are caused by inflammatory stimuli interacting with intracellular messengers to remodel cytoskeletal junctions and adhesion proteins. Those phenomena are associated with sepsis, acute lung injury, and acute respiratory distress syndrome. The molecular processes beyond those responses are the main interest of our group. Unfolded protein response (UPR) is a highly conserved molecular pathway resolving protein-folding defects to counteract cellular threats. An emerging body of evidence suggests that UPR is a promising target against lung and cardiovascular disease. In the present study, we reveal that Tunicamycin (TM) (UPR inducer) protects against lipopolysaccharide (LPS)-induced injury. The barrier function of the inflamed endothelium was evaluated in vitro (transendothelial and paracellular permeability); as well as in mice exposed to TM after LPS. Our study demonstrates that TM supports vascular barrier function by modulating actomyosin remodeling. Moreover, it reduces the internalization of vascular endothelial cadherin (VE-cadherin), enhancing endothelial integrity. We suggest that UPR activation may deliver novel therapeutic opportunities in diseases related to endothelial dysregulation.
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9
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An Insight into GPCR and G-Proteins as Cancer Drivers. Cells 2021; 10:cells10123288. [PMID: 34943797 PMCID: PMC8699078 DOI: 10.3390/cells10123288] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/17/2021] [Accepted: 11/22/2021] [Indexed: 12/14/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are the largest family of cell surface signaling receptors known to play a crucial role in various physiological functions, including tumor growth and metastasis. Various molecules such as hormones, lipids, peptides, and neurotransmitters activate GPCRs that enable the coupling of these receptors to highly specialized transducer proteins, called G-proteins, and initiate multiple signaling pathways. Integration of these intricate networks of signaling cascades leads to numerous biochemical responses involved in diverse pathophysiological activities, including cancer development. While several studies indicate the role of GPCRs in controlling various aspects of cancer progression such as tumor growth, invasion, migration, survival, and metastasis through its aberrant overexpression, mutations, or increased release of agonists, the explicit mechanisms of the involvement of GPCRs in cancer progression is still puzzling. This review provides an insight into the various responses mediated by GPCRs in the development of cancers, the molecular mechanisms involved and the novel pharmacological approaches currently preferred for the treatment of cancer. Thus, these findings extend the knowledge of GPCRs in cancer cells and help in the identification of therapeutics for cancer patients.
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10
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Verdinez JA, Sebag JA. Role of N-Linked Glycosylation in PKR2 Trafficking and Signaling. Front Neurosci 2021; 15:730417. [PMID: 34483834 PMCID: PMC8414166 DOI: 10.3389/fnins.2021.730417] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/27/2021] [Indexed: 12/26/2022] Open
Abstract
Prokineticin receptors are GPCRs involved in several physiological processes including the regulation of energy homeostasis, nociception, and reproductive function. PKRs are inhibited by the endogenous accessory protein MRAP2 which prevents them from trafficking to the plasma membrane. Very little is known about the importance of post-translational modification of PKRs and their role in receptor trafficking and signaling. Here we identify 2 N-linked glycosylation sites within the N-terminal region of PKR2 and demonstrate that glycosylation of PKR2 at position 27 is important for its plasma membrane localization and signaling. Additionally, we show that glycosylation at position 7 results in a decrease in PKR2 signaling through Gαs without impairing Gαq/11 signaling.
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Affiliation(s)
- Jissele A Verdinez
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
| | - Julien A Sebag
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA, United States.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
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11
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Karki R, Rimal S, Rieth MD. Predicted N-terminal N-linked glycosylation sites may underlie membrane protein expression patterns in Saccharomyces cerevisiae. Yeast 2021; 38:497-506. [PMID: 34182612 DOI: 10.1002/yea.3657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 12/14/2022] Open
Abstract
N-linked glycosylation is one type of posttranslational modification that proteins undergo during expression. The following describes the effects of N-linked glycosylation on high-level membrane protein expression in yeast with an emphasis on Saccharomyces cerevisiae. N-linked glycosylation is highlighted here as an important consideration when preparing membrane protein gene constructs for expression in S. cerevisiae, which continues to be used as a workhorse in both research and industrial applications. Non-native N-linked glycosylation commonly occurs during the heterologous expression of mammalian proteins in many yeast species which can have important immunological consequences when used in the production of biotherapeutic proteins or peptides. Further, non-native N-linked glycosylation can lead to improper protein folding and premature degradation, which can impede high-level expression yields and hinder downstream analysis. Multiple strategies are presented in this article, which suggest different methods that can be implemented to circumvent the unwanted consequences of N-linked glycosylation during the expression process. These considerations may have long-term benefits for high-level protein production in S. cerevisiae across a broad spectrum of expression targets with special emphasis placed on G-protein coupled receptors, one of the largest families of membrane proteins.
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Affiliation(s)
- Rashmi Karki
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Swechha Rimal
- Department of Chemistry, Southern Illinois University Edwardsville, Edwardsville, Illinois, USA
| | - Monica D Rieth
- Department of Chemistry, Southern Illinois University Edwardsville, Edwardsville, Illinois, USA
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12
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Wang W, Tian Y, Shi X, Ma Q, Xu Y, Yang G, Yi W, Shi Y, Zhou N. N-glycosylation of the human neuropeptide QRFP receptor (QRFPR) is essential for ligand binding and receptor activation. J Neurochem 2021; 158:138-152. [PMID: 33655503 DOI: 10.1111/jnc.15337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 11/29/2022]
Abstract
The newly identified pyroglutamylated RFamide peptide (QRFP) signaling system has been shown to be implicated in regulating a variety of physiological processes. G-protein-coupled receptors (GPCRs) are preferentially N-glycosylated on extracellular domains. The human QRFP receptor QRFPR (GPR103) possesses three N-glycosylation consensus sites, two located on the N-terminal domain (N5 and N19) and one on the first extracellular loop (ECL1) (N106); however, to date, their role in QRFPR expression and signaling has not been established. Here, we combined mutants with glutamine substitution of the critical asparagines of the consensus sites with glycosidase PNGase F and N-glycosylation inhibitor tunicamycin to study the effect of N-glycosylation in the regulation of QRFPR cell surface expression and signaling. Western blot analysis performed with site-directed mutagenesis revealed that two asparagines at N19 in the N-terminus and N106 in ECL1, but not N5 in the N-terminus, served as sites for N-glycosylation. Treatment with PNGase F and tunicamycin resulted in a reduction in both two-protein species, ~43 kDa and ~85 kDa in size, by 2-4 kDa. Analysis with confocal microscopy and quantitative ELISA showed that N-glycosylation of QRFPR is not essentially required for targeting the cell membrane. However, further binding assay and functional assays demonstrated that removal of N-glycosylation sequons or treatment with tunicamycin led to significant impairments in the interaction of receptor with QRFP26 and downstream signaling. Thus, our findings suggest that for the human QRFP receptor (QRFPR), N-glycosylation is not important for cell surface expression but is a pre-requisite for ligand binding and receptor activation.
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Affiliation(s)
- Weiwei Wang
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yanan Tian
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoliu Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qiang Ma
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yue Xu
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Gangjie Yang
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wen Yi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ying Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Naiming Zhou
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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Wu J, Heemskerk JWM, Baaten CCFMJ. Platelet Membrane Receptor Proteolysis: Implications for Platelet Function. Front Cardiovasc Med 2021; 7:608391. [PMID: 33490118 PMCID: PMC7820117 DOI: 10.3389/fcvm.2020.608391] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022] Open
Abstract
The activities of adhesion and signaling receptors in platelets are controlled by several mechanisms. An important way of regulation is provided by proteolytic cleavage of several of these receptors, leading to either a gain or a loss of platelet function. The proteases involved are of different origins and types: (i) present as precursor in plasma, (ii) secreted into the plasma by activated platelets or other blood cells, or (iii) intracellularly activated and cleaving cytosolic receptor domains. We provide a comprehensive overview of the proteases acting on the platelet membrane. We describe how these are activated, which are their target proteins, and how their proteolytic activity modulates platelet functions. The review focuses on coagulation-related proteases, plasmin, matrix metalloproteinases, ADAM(TS) isoforms, cathepsins, caspases, and calpains. We also describe how the proteolytic activities are determined by different platelet populations in a thrombus and conversely how proteolysis contributes to the formation of such populations.
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Affiliation(s)
- Jiayu Wu
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Johan W. M. Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Constance C. F. M. J. Baaten
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
- Institute for Molecular Cardiovascular Research (IMCAR), University Hospital Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Aachen, Germany
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14
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Patwardhan A, Cheng N, Trejo J. Post-Translational Modifications of G Protein-Coupled Receptors Control Cellular Signaling Dynamics in Space and Time. Pharmacol Rev 2021; 73:120-151. [PMID: 33268549 PMCID: PMC7736832 DOI: 10.1124/pharmrev.120.000082] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are a large family comprising >800 signaling receptors that regulate numerous cellular and physiologic responses. GPCRs have been implicated in numerous diseases and represent the largest class of drug targets. Although advances in GPCR structure and pharmacology have improved drug discovery, the regulation of GPCR function by diverse post-translational modifications (PTMs) has received minimal attention. Over 200 PTMs are known to exist in mammalian cells, yet only a few have been reported for GPCRs. Early studies revealed phosphorylation as a major regulator of GPCR signaling, whereas later reports implicated a function for ubiquitination, glycosylation, and palmitoylation in GPCR biology. Although our knowledge of GPCR phosphorylation is extensive, our knowledge of the modifying enzymes, regulation, and function of other GPCR PTMs is limited. In this review we provide a comprehensive overview of GPCR post-translational modifications with a greater focus on new discoveries. We discuss the subcellular location and regulatory mechanisms that control post-translational modifications of GPCRs. The functional implications of newly discovered GPCR PTMs on receptor folding, biosynthesis, endocytic trafficking, dimerization, compartmentalized signaling, and biased signaling are also provided. Methods to detect and study GPCR PTMs as well as PTM crosstalk are further highlighted. Finally, we conclude with a discussion of the implications of GPCR PTMs in human disease and their importance for drug discovery. SIGNIFICANCE STATEMENT: Post-translational modification of G protein-coupled receptors (GPCRs) controls all aspects of receptor function; however, the detection and study of diverse types of GPCR modifications are limited. A thorough understanding of the role and mechanisms by which diverse post-translational modifications regulate GPCR signaling and trafficking is essential for understanding dysregulated mechanisms in disease and for improving and refining drug development for GPCRs.
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Affiliation(s)
- Anand Patwardhan
- Department of Pharmacology and the Biomedical Sciences Graduate Program, School of Medicine, University of California, San Diego, La Jolla, California
| | - Norton Cheng
- Department of Pharmacology and the Biomedical Sciences Graduate Program, School of Medicine, University of California, San Diego, La Jolla, California
| | - JoAnn Trejo
- Department of Pharmacology and the Biomedical Sciences Graduate Program, School of Medicine, University of California, San Diego, La Jolla, California
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15
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Lee S. Asn-linked N-acetylglucosamine of the amylin receptor 2 extracellular domain enhances peptide ligand affinity. FEBS Open Bio 2020; 11:195-206. [PMID: 33227824 PMCID: PMC7780097 DOI: 10.1002/2211-5463.13042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/09/2020] [Accepted: 11/16/2020] [Indexed: 11/07/2022] Open
Abstract
The calcitonin receptor (CTR) has a large extracellular domain (ECD) with multiple N‐glycosylation sites. An asparagine (Asn)‐linked N‐acetylglucosamine (GlcNAc) of CTR ECD N130 was previously reported to enhance peptide hormone binding affinity for CTR ECD. CTR forms a complex with an accessory protein RAMP, and the RAMP:CTR complex gains affinity for peptide hormone amylin as the amylin receptor (AMY). Although N‐glycosylation of AMY ECD was reported to enhance peptide hormone affinity, it remains underexplored which N‐glycosites of AMY ECD are responsible for peptide affinity enhancement and it is unclear whether an Asn‐linked GlcNAc of the N‐glycosites plays a critical role. Here, I investigated the role of the Asn‐linked GlcNAc of CTR N130 in the affinity of an antagonistic amylin analog (AC413) for AMY2 ECD (the RAMP2 ECD:CTR ECD complex). I used Endo H‐treated CTR ECD in which N‐glycans were trimmed to an Asn‐linked GlcNAc on each of the N‐glycosites. I incubated Endo H‐treated CTR ECD with excess of glycan‐free RAMP2 ECD to produce the RAMP2 ECD:CTR ECD complex. Using this coincubation system, I found that the RAMP2 ECD complex with Endo H‐treated CTR ECD with N130D mutation showed a fourfold decrease in AC413 affinity compared with the RAMP2 ECD complex with Endo H‐treated CTR ECD WT. In contrast, RAMP2 ECD N‐glycosylation did not affect peptide binding affinity. These results indicate that the Asn‐linked GlcNAc of CTR N130 is an important peptide affinity enhancer for AMY2 ECD and reveals a significant role of the Asn‐linked GlcNAc in AMY2 function.
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Affiliation(s)
- Sangmin Lee
- Department of Basic Pharmaceutical SciencesFred Wilson School of PharmacyHigh Point UniversityHigh PointNCUSA
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16
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Antigen Design for Successful Isolation of Highly Challenging Therapeutic Anti-GPCR Antibodies. Int J Mol Sci 2020; 21:ijms21218240. [PMID: 33153215 PMCID: PMC7663707 DOI: 10.3390/ijms21218240] [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: 10/12/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 02/03/2023] Open
Abstract
G-protein-coupled receptors (GPCR) transmit extracellular signals into cells to regulate a variety of cellular functions and are closely related to the homeostasis of the human body and the progression of various types of diseases. Great attention has been paid to GPCRs as excellent drug targets, and there are many commercially available small-molecule chemical drugs against GPCRs. Despite this, the development of therapeutic anti-GPCR antibodies has been delayed and is challenging due to the difficulty in preparing active forms of GPCR antigens, resulting from their low cellular expression and complex structures. Here, we focus on anti-GPCR antibodies that have been approved or are subject to clinical trials and present various technologies to prepare active GPCR antigens that enable the isolation of therapeutic antibodies to proceed toward clinical validation.
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Han X, Nieman MT. The domino effect triggered by the tethered ligand of the protease activated receptors. Thromb Res 2020; 196:87-98. [PMID: 32853981 DOI: 10.1016/j.thromres.2020.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/23/2020] [Accepted: 08/03/2020] [Indexed: 12/20/2022]
Abstract
Protease activated receptors (PARs) are G-protein coupled receptors (GPCRs) that have a unique activation mechanism. Unlike other GPCRs that can be activated by free ligands, under physiological conditions, PARs are activated by the tethered ligand, which is a part of their N-terminus that is unmasked by proteolysis. It has been 30 years since the first member of the family, PAR1, was identified. In this review, we will discuss this unique tethered ligand mediate receptor activation of PARs in detail: how they interact with the proteases, the complex structural rearrangement of the receptors upon activation, and the termination of the signaling. We also summarize the structural studies of the PARs and how single nucleotide polymorphisms impact the receptor reactivity. Finally, we review the current strategies for inhibiting PAR function with therapeutic targets for anti-thrombosis. The focus of this review is PAR1 and PAR4 as they are the thrombin signal mediators on human platelets and therapeutics targets. We also include the structural studies of PAR2 as it informs the mechanism of action for PARs in general.
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Affiliation(s)
- Xu Han
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Marvin T Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA.
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18
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Goth CK, Petäjä-Repo UE, Rosenkilde MM. G Protein-Coupled Receptors in the Sweet Spot: Glycosylation and other Post-translational Modifications. ACS Pharmacol Transl Sci 2020; 3:237-245. [PMID: 32296765 DOI: 10.1021/acsptsci.0c00016] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Indexed: 12/11/2022]
Abstract
Post-translational modifications (PTMs) are a fundamental phenomenon across all classes of life and several hundred different types have been identified. PTMs contribute widely to the biological functions of proteins and greatly increase their diversity. One important class of proteins regulated by PTMs, is the cell surface expressed G protein-coupled receptors (GPCRs). While most PTMs have been shown to exert distinct biological functions, we are only beginning to approach the complexity that the potential interplay between different PTMs may have on biological functions and their regulation. Importantly, PTMs and their potential interplay represent an appealing mechanism for cell and tissue specific regulation of GPCR function and may partially contribute to functional selectivity of some GPCRs. In this review we highlight examples of PTMs located in GPCR extracellular domains, with special focus on glycosylation and the potential interplay with other close-by PTMs such as tyrosine sulfation, proteolytic cleavage, and phosphorylation.
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Affiliation(s)
- Christoffer K Goth
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK 2200, Denmark
| | - Ulla E Petäjä-Repo
- Medical Research Center Oulu, Research Unit of Biomedicine, University of Oulu, Oulu, FI-90014, Finland
| | - 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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19
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Lee SM, Jeong Y, Simms J, Warner ML, Poyner DR, Chung KY, Pioszak AA. Calcitonin Receptor N-Glycosylation Enhances Peptide Hormone Affinity by Controlling Receptor Dynamics. J Mol Biol 2020; 432:1996-2014. [PMID: 32035902 DOI: 10.1016/j.jmb.2020.01.028] [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] [Received: 08/24/2019] [Revised: 11/27/2019] [Accepted: 01/27/2020] [Indexed: 02/09/2023]
Abstract
The class B G protein-coupled receptor (GPCR) calcitonin receptor (CTR) is a drug target for osteoporosis and diabetes. N-glycosylation of asparagine 130 in its extracellular domain (ECD) enhances calcitonin hormone affinity with the proximal GlcNAc residue mediating this effect through an unknown mechanism. Here, we present two crystal structures of salmon calcitonin-bound, GlcNAc-bearing CTR ECD at 1.78 and 2.85 Å resolutions and analyze the mechanism of the glycan effect. The N130 GlcNAc does not contact the hormone. Surprisingly, the structures are nearly identical to a structure of hormone-bound, N-glycan-free ECD, which suggested that the GlcNAc might affect CTR dynamics not observed in the static crystallographic snapshots. Hydrogen-deuterium exchange mass spectrometry and molecular dynamics simulations revealed that glycosylation stabilized a β-sheet adjacent to the N130 GlcNAc and the N-terminal α-helix near the peptide-binding site while increasing flexibility of the peptide-binding site turret loop. These changes due to N-glycosylation increased the ligand on-rate and decreased its off-rate. The glycan effect extended to RAMP-CTR amylin receptor complexes and was also conserved in the related CGRP receptor. These results reveal that N-glycosylation can modulate GPCR function by altering receptor dynamics.
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Affiliation(s)
- Sang-Min Lee
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA; Present Address: Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, High Point, NC, 27268, USA
| | - Yejin Jeong
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - John Simms
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - Margaret L Warner
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - David R Poyner
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK
| | - Ka Young Chung
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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20
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Willis Fox O, Preston RJS. Molecular basis of protease-activated receptor 1 signaling diversity. J Thromb Haemost 2020; 18:6-16. [PMID: 31549766 DOI: 10.1111/jth.14643] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/13/2019] [Accepted: 09/17/2019] [Indexed: 12/13/2022]
Abstract
Protease-activated receptors (PARs) are a family of highly conserved G protein-coupled receptors (GPCRs) that respond to extracellular proteases via a unique proteolysis-dependent activation mechanism. Protease-activated receptor 1 (PAR1) was the first identified member of the receptor family and plays important roles in hemostasis, inflammation and malignancy. The biology underlying PAR1 signaling by its canonical agonist thrombin is well characterized; however, definition of the mechanistic basis of PAR1 signaling by other proteases, including matrix metalloproteases, activated protein C, plasmin, and activated factors VII and X, remains incompletely understood. In this review, we discuss emerging insights into the molecular bases for "biased" PAR1 signaling, including atypical PAR1 proteolysis, PAR1 heterodimer and coreceptor interactions, PAR1 translocation on the membrane surface, and interactions with different G-proteins and β-arrestins upon receptor activation. Moreover, we consider how these new insights into PAR1 signaling have acted to spur development of novel PAR1-targeted therapeutics that act to inhibit, redirect, or fine-tune PAR1 signaling output to treat cardiovascular and inflammatory disease. Finally, we discuss some of the key unanswered questions relating to PAR1 biology, in particular how differences in PAR1 proteolysis, signaling intermediate coupling, and engagement with coreceptors and GPCRs combine to mediate the diversity of identified PAR1 signaling outputs.
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Affiliation(s)
- Orla Willis Fox
- Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
- Department of Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Roger J S Preston
- Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
- Department of Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
- National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland
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21
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A Tyrosine Switch on NEDD4-2 E3 Ligase Transmits GPCR Inflammatory Signaling. Cell Rep 2019; 24:3312-3323.e5. [PMID: 30232011 PMCID: PMC6226018 DOI: 10.1016/j.celrep.2018.08.061] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 07/05/2018] [Accepted: 08/21/2018] [Indexed: 02/03/2023] Open
Abstract
Ubiquitination is essential for protein degradation and signaling and pivotal to many physiological processes. Ubiquitination of a subset of G-protein-coupled receptors (GPCRs) by the E3 ligase NEDD4–2 is required for p38 activation, but how GPCRs activate NEDD4–2 to promote ubiquitinmediated signaling is not known. Here, we report that the GPCR protease-activated receptor-1 (PAR1) stimulates c-Src-mediated tyrosine phosphorylation and activation of NEDD4–2 to promote p38 signaling and endothelial barrier disruption. Using mass spectrometry, we identified a unique phosphorylated tyrosine (Y)-485 within the 2,3-linker peptide between WW domain 2 and 3 of NEDD4–2 in agonist-stimulated cells. Mutation of NEDD4–2 Y485 impaired E3 ligase activity and failed to rescue PAR1-stimulated p38 activation and endothelial barrier permeability. The purinergic P2Y1 receptor also required c-Src and NEDD4–2 tyrosine phosphorylation for p38 activation. These studies reveal a novel role for c-Src in GPCR-induced NEDD4–2 activation, which is critical for driving ubiquitin-mediated p38 inflammatory signaling. Grimsey et al. report that GPCRs stimulate activation of NEDD4–2 E3 ubiquitin ligase via c-Src to induce endothelial p38 inflammatory signaling. c-Src phosphorylates NEDD4–2 at tyrosine-485, releasing the autoinhibitory linker peptide that is critical for enhancing E3 ligase activity, and provides mechanistic insight of how GPCRs activate E3 ubiquitin ligases.
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22
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Read C, Nyimanu D, Williams TL, Huggins DJ, Sulentic P, Macrae RGC, Yang P, Glen RC, Maguire JJ, Davenport AP. International Union of Basic and Clinical Pharmacology. CVII. Structure and Pharmacology of the Apelin Receptor with a Recommendation that Elabela/Toddler Is a Second Endogenous Peptide Ligand. Pharmacol Rev 2019; 71:467-502. [PMID: 31492821 PMCID: PMC6731456 DOI: 10.1124/pr.119.017533] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The predicted protein encoded by the APJ gene discovered in 1993 was originally classified as a class A G protein-coupled orphan receptor but was subsequently paired with a novel peptide ligand, apelin-36 in 1998. Substantial research identified a family of shorter peptides activating the apelin receptor, including apelin-17, apelin-13, and [Pyr1]apelin-13, with the latter peptide predominating in human plasma and cardiovascular system. A range of pharmacological tools have been developed, including radiolabeled ligands, analogs with improved plasma stability, peptides, and small molecules including biased agonists and antagonists, leading to the recommendation that the APJ gene be renamed APLNR and encode the apelin receptor protein. Recently, a second endogenous ligand has been identified and called Elabela/Toddler, a 54-amino acid peptide originally identified in the genomes of fish and humans but misclassified as noncoding. This precursor is also able to be cleaved to shorter sequences (32, 21, and 11 amino acids), and all are able to activate the apelin receptor and are blocked by apelin receptor antagonists. This review summarizes the pharmacology of these ligands and the apelin receptor, highlights the emerging physiologic and pathophysiological roles in a number of diseases, and recommends that Elabela/Toddler is a second endogenous peptide ligand of the apelin receptor protein.
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Affiliation(s)
- Cai Read
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - Duuamene Nyimanu
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - Thomas L Williams
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - David J Huggins
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - Petra Sulentic
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - Robyn G C Macrae
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - Peiran Yang
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - Robert C Glen
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - Janet J Maguire
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
| | - Anthony P Davenport
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge, United Kingdom (C.R., D.N., T.L.W., D.J.H., P.S., R.G.C.M., P.Y., J.J.M., A.P.D.); The Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom (D.J.H., R.C.G.); and Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, United Kingdom (R.C.G.)
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Effects of Post-translational Modifications on Membrane Localization and Signaling of Prostanoid GPCR-G Protein Complexes and the Role of Hypoxia. J Membr Biol 2019; 252:509-526. [PMID: 31485700 DOI: 10.1007/s00232-019-00091-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/17/2019] [Indexed: 02/07/2023]
Abstract
G protein-coupled receptors (GPCRs) play a pivotal role in the adaptive responses to cellular stresses such as hypoxia. In addition to influencing cellular gene expression profiles, hypoxic microenvironments can perturb membrane protein localization, altering GPCR effector scaffolding and altering downstream signaling. Studies using proteomics approaches have revealed significant regulation of GPCR and G proteins by their state of post-translational modification. The aim of this review is to examine the effects of post-translational modifications on membrane localization and signaling of GPCR-G protein complexes, with an emphasis on vascular prostanoid receptors, and to highlight what is known about the effect of cellular hypoxia on these mechanisms. Understanding post-translational modifications of protein targets will help to define GPCR targets in treatment of disease, and to inform research into mechanisms of hypoxic cellular responses.
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Modulation of Endocannabinoid-Binding Receptors in Human Neuroblastoma Cells by Tunicamycin. Molecules 2019; 24:molecules24071432. [PMID: 30979007 PMCID: PMC6479803 DOI: 10.3390/molecules24071432] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/09/2019] [Accepted: 04/09/2019] [Indexed: 01/22/2023] Open
Abstract
Endocannabinoid (eCB)-binding receptors can be modulated by several ligands and membrane environment, yet the effect of glycosylation remains to be assessed. In this study, we used human neuroblastoma SH-SY5Y cells to interrogate whether expression, cellular localization, and activity of eCB-binding receptors may depend on N-linked glycosylation. Following treatment with tunicamycin (a specific inhibitor of N-linked glycosylation) at the non-cytotoxic dose of 1 µg/mL, mRNA, protein levels and localization of eCB-binding receptors, as well as N-acetylglucosamine (GlcNAc) residues, were evaluated in SH-SY5Y cells by means of quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR), fluorescence-activated cell sorting (FACS), and confocal microscopy, respectively. In addition, the activity of type-1 and type-2 cannabinoid receptors (CB1 and CB2) was assessed by means of rapid binding assays. Significant changes in gene and protein expression were found upon tunicamycin treatment for CB1 and CB2, as well as for GPR55 receptors, but not for transient receptor potential vanilloid 1 (TRPV1). Deglycosylation experiments with N-glycosidase-F and immunoblot of cell membranes derived from SH-SY5Y cells confirmed the presence of one glycosylated form in CB1 (70 kDa), that was reduced by tunicamycin. Morphological studies demonstrated the co-localization of CB1 with GlcNAc residues, and showed that tunicamycin reduced CB1 membrane expression with a marked nuclear localization, as confirmed by immunoblotting. Cleavage of the carbohydrate side chain did not modify CB receptor binding affinity. Overall, these results support N-linked glycosylation as an unprecedented post-translational modification that may modulate eCB-binding receptors’ expression and localization, in particular for CB1.
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Liu X, Yang L, Zhang D, Liu T, Yan Q, Yang X. Deglycosylation of epithelial cell adhesion molecule affects epithelial to mesenchymal transition in breast cancer cells. J Cell Physiol 2018; 234:4504-4514. [DOI: 10.1002/jcp.27256] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/20/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Xue Liu
- Liaoning Provincial Core Lab of Glycobiology and Glycoengineering, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Dalian Medical University Dalian China
| | - Liu Yang
- Liaoning Provincial Core Lab of Glycobiology and Glycoengineering, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Dalian Medical University Dalian China
| | - Dandan Zhang
- Liaoning Provincial Core Lab of Glycobiology and Glycoengineering, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Dalian Medical University Dalian China
| | - Tingjiao Liu
- Department of Oral Pathology, College of Stomatology, Dalian Medical University Dalian China
| | - Qiu Yan
- Liaoning Provincial Core Lab of Glycobiology and Glycoengineering, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Dalian Medical University Dalian China
| | - Xuesong Yang
- Liaoning Provincial Core Lab of Glycobiology and Glycoengineering, Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Dalian Medical University Dalian China
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Clement N, Renault N, Guillaume J, Cecon E, Journé A, Laurent X, Tadagaki K, Cogé F, Gohier A, Delagrange P, Chavatte P, Jockers R. Importance of the second extracellular loop for melatonin MT 1 receptor function and absence of melatonin binding in GPR50. Br J Pharmacol 2018; 175:3281-3297. [PMID: 28898928 PMCID: PMC6057912 DOI: 10.1111/bph.14029] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/09/2017] [Accepted: 09/03/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Recent crystal structures of GPCRs have emphasized the previously unappreciated role of the second extracellular (E2) loop in ligand binding and gating and receptor activation. Here, we have assessed the role of the E2 loop in the activation of the melatonin MT1 receptor and in the inactivation of the closely related orphan receptor GPR50. EXPERIMENTAL APPROACH Chimeric MT1 -GPR50 receptors were generated and functionally analysed in terms of 2-[125 I]iodomelatonin binding, Gi /cAMP signalling and β-arrestin2 recruitment. We also used computational molecular dynamics (MD) simulations. KEY RESULTS MD simulations of 300 ns revealed (i) the tight hairpin structure of the E2 loop of the MT1 receptor (ii) the most suitable features for melatonin binding in MT1 receptors and (iii) major predicted rearrangements upon MT1 receptor activation, stabilizing interaction networks between Phe179 or Gln181 in the E2 loop and transmembrane helixes 5 and 6. Functional assays confirmed these predictions, because reciprocal replacement of MT1 and GPR50 residues/domains led to the predicted loss- and gain-of-melatonin action of MT1 receptors and GPR50 respectively. CONCLUSIONS AND IMPLICATIONS Our work demonstrated the crucial role of the E2 loop for MT1 receptor and GPR50 function by proposing a model in which the E2 loop is important in stabilizing active MT1 receptor conformations and by showing how evolutionary processes appear to have selected for modifications in the E2 loop in order to make GPR50 unresponsive to melatonin. LINKED ARTICLES This article is part of a themed section on Recent Developments in Research of Melatonin and its Potential Therapeutic Applications. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.16/issuetoc.
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Affiliation(s)
- Nathalie Clement
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Nicolas Renault
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International CenterLilleFrance
| | - Jean‐Luc Guillaume
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Erika Cecon
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Anne‐Sophie Journé
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Xavier Laurent
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International CenterLilleFrance
| | - Kenjiro Tadagaki
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Francis Cogé
- Pôle d'Innovation Thérapeutique NeuropsychiatrieInstitut de Recherches SERVIERCroissy/SeineFrance
| | - Arnaud Gohier
- Pôle d'Innovation Thérapeutique NeuropsychiatrieInstitut de Recherches SERVIERCroissy/SeineFrance
| | - Philippe Delagrange
- Pôle d'Innovation Thérapeutique NeuropsychiatrieInstitut de Recherches SERVIERCroissy/SeineFrance
| | - Philippe Chavatte
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International CenterLilleFrance
| | - Ralf Jockers
- Inserm, U1016, Institut CochinParisFrance
- CNRS UMR 8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
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Gerzanich V, Kwon MS, Woo SK, Ivanov A, Simard JM. SUR1-TRPM4 channel activation and phasic secretion of MMP-9 induced by tPA in brain endothelial cells. PLoS One 2018; 13:e0195526. [PMID: 29617457 PMCID: PMC5884564 DOI: 10.1371/journal.pone.0195526] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 03/23/2018] [Indexed: 11/25/2022] Open
Abstract
Background Hemorrhagic transformation is a major complication of ischemic stroke, is linked to matrix metalloproteinase-9 (MMP-9), and is exacerbated by tissue plasminogen activator (tPA). Cerebral ischemia/reperfusion is characterized by SUR1-TRPM4 (sulfonylurea receptor 1—transient receptor potential melastatin 4) channel upregulation in microvascular endothelium. In humans and rodents with cerebral ischemia/reperfusion (I/R), the SUR1 antagonist, glibenclamide, reduces hemorrhagic transformation and plasma MMP-9, but the mechanism is unknown. We hypothesized that tPA induces protease activated receptor 1 (PAR1)-mediated, Ca2+-dependent phasic secretion of MMP-9 from activated brain endothelium, and that SUR1-TRPM4 is required for this process. Methods Cerebral I/R, of 2 and 4 hours duration, respectively, was obtained using conventional middle cerebral artery occlusion. Immunolabeling was used to quantify p65 nuclear translocation. Murine and human brain endothelial cells (BEC) were studied in vitro, without and with NF-κB activation, using immunoblot, zymography and ELISA, patch clamp electrophysiology, and calcium imaging. Genetic and pharmacological manipulations were used to identify signaling pathways. Results Cerebral I/R caused prominent nuclear translocation of p65 in microvascular endothelium. NF-κB-activation of BEC caused de novo expression of SUR1-TRPM4 channels. In NF-κB-activated BEC: (i) tPA caused opening of SUR1-TRPM4 channels in a plasmin-, PAR1-, TRPC3- and Ca2+-dependent manner; (ii) tPA caused PAR1-dependent secretion of MMP-9; (iii) tonic secretion of MMP-9 by activated BEC was not influenced by SUR1 inhibition; (iv) phasic secretion of MMP-9 induced by tPA or the PAR1-agonist, TFLLR, required functional SUR1-TRPM4 channels, with inhibition of SUR1 decreasing tPA-induced MMP-9 secretion. Conclusions tPA induces PAR1-mediated, SUR1-TRPM4-dependent, phasic secretion of MMP-9 from activated brain endothelium.
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Affiliation(s)
- Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Min Seong Kwon
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Seung Kyoon Woo
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alexander Ivanov
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - J. Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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29
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Readmond C, Wu C. Investigating detailed interactions between novel PAR1 antagonist F16357 and the receptor using docking and molecular dynamic simulations. J Mol Graph Model 2017; 77:205-217. [DOI: 10.1016/j.jmgm.2017.08.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 01/08/2023]
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Woolley MJ, Conner AC. Understanding the common themes and diverse roles of the second extracellular loop (ECL2) of the GPCR super-family. Mol Cell Endocrinol 2017; 449:3-11. [PMID: 27899324 DOI: 10.1016/j.mce.2016.11.023] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/02/2016] [Accepted: 11/24/2016] [Indexed: 11/16/2022]
Abstract
The extracellular loops (ECLs) of G protein-coupled receptors (GPCRs) can bind directly to docked orthosteric or allosteric ligands, they can contain transient contact points for ligand entry into the transmembrane (TM) bundle and they can regulate the activation of the receptor signalling pathways. Of the three ECLs, ECL2 is the largest and most structurally diverse reflecting its functional importance. This has been shown through biochemical techniques and has been supported by the many subsequent crystal structures of GPCRs bound to both agonists and antagonists. ECL2 shares common structural features between (and sometimes across) receptor sub-families and can facilitate ligand entry to the TM core or act directly as a surface of the ligand-binding pocket. Structural similarities seem to underpin common binding mechanisms; however, where these exist, variations in primary sequence ensure ligand-binding specificity. This review will compare current understanding of the structural themes and main functional roles of ECL2 in ligand binding, activation and regulation of the major families of GPCRs.
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Affiliation(s)
- Michael J Woolley
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Alex C Conner
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.
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Lee SM, Booe JM, Gingell JJ, Sjoelund V, Hay DL, Pioszak AA. N-Glycosylation of Asparagine 130 in the Extracellular Domain of the Human Calcitonin Receptor Significantly Increases Peptide Hormone Affinity. Biochemistry 2017; 56:3380-3393. [PMID: 28614667 DOI: 10.1021/acs.biochem.7b00256] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The calcitonin receptor (CTR) is a class B G protein-coupled receptor that is activated by the peptide hormones calcitonin and amylin. Calcitonin regulates bone remodeling through CTR, whereas amylin regulates blood glucose and food intake by activating CTR in complex with receptor activity-modifying proteins (RAMPs). These receptors are targeted clinically for the treatment of osteoporosis and diabetes. Here, we define the role of CTR N-glycosylation in hormone binding using purified calcitonin and amylin receptor extracellular domain (ECD) glycoforms and fluorescence polarization/anisotropy and isothermal titration calorimetry peptide-binding assays. N-Glycan-free CTR ECD produced in Escherichia coli exhibited ∼10-fold lower peptide affinity than CTR ECD produced in HEK293T cells, which yield complex N-glycans, or in HEK293S GnTI- cells, which yield core N-glycans (Man5GlcNAc2). PNGase F-catalyzed removal of N-glycans at N73, N125, and N130 in the CTR ECD decreased peptide affinity ∼10-fold, whereas Endo H-catalyzed trimming of the N-glycans to single GlcNAc residues had no effect on peptide binding. Similar results were observed for an amylin receptor RAMP2-CTR ECD complex. Characterization of peptide-binding affinities of purified N → Q CTR ECD glycan site mutants combined with PNGase F and Endo H treatment strategies and mass spectrometry to define the glycan species indicated that a single GlcNAc residue at CTR N130 was responsible for the peptide affinity enhancement. Molecular modeling suggested that this GlcNAc functions through an allosteric mechanism rather than by directly contacting the peptide. These results reveal an important role for N-linked glycosylation in the peptide hormone binding of a clinically relevant class B GPCR.
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Affiliation(s)
- Sang-Min Lee
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center , 975 NE 10th Street BRC 462B, Oklahoma City, Oklahoma 73104, United States
| | - Jason M Booe
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center , 975 NE 10th Street BRC 462B, Oklahoma City, Oklahoma 73104, United States
| | | | - Virginie Sjoelund
- Proteomics Division of the Laboratory for Molecular Biology and Cytometry Research, University of Oklahoma Health Sciences Center , 975 NE 10th Street, Oklahoma City, Oklahoma 73104, United States
| | | | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center , 975 NE 10th Street BRC 462B, Oklahoma City, Oklahoma 73104, United States
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Benredjem B, Dallaire P, Pineyro G. Analyzing biased responses of GPCR ligands. Curr Opin Pharmacol 2017; 32:71-76. [DOI: 10.1016/j.coph.2016.11.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 11/11/2016] [Accepted: 11/18/2016] [Indexed: 10/20/2022]
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Bhattacharya S, Salomon-Ferrer R, Lee S, Vaidehi N. Conserved Mechanism of Conformational Stability and Dynamics in G-Protein-Coupled Receptors. J Chem Theory Comput 2016; 12:5575-5584. [PMID: 27709935 DOI: 10.1021/acs.jctc.6b00618] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
G-protein-coupled receptors (GPCRs) are transmembrane receptors involved in diverse biological functions. Despite the diversity in their amino acid sequences, class A GPCRs exhibit a conserved structural topology and possibly a common mechanism of receptor activation. To understand how this high sequence diversity translates to a conserved functional mechanism, we have compared the dynamic behavior of eight class A GPCRs comprised of six biogenic amine receptors, adenosine A2A, and the peptide receptor protease-activated receptor 1. Starting from the crystal structures of the inactive state of these receptors bound to inverse agonists or antagonists, we have performed multiple all-atom MD simulations adding up to several microseconds of simulation. We elucidated the similarities and differences in the dynamic behavior and the conformational ensembles sampled by these eight class A GPCRs. Among the six biogenic amine receptors studied here, β2-adrenergic receptor shows the highest level of fluctuation in the sixth and seventh transmembrane helices, possibly explaining its high basal activity. In contrast, the muscarinic acetylcholine receptors show the lowest fluctuations as well as tight packing and low hydration of the transmembrane domain. All eight GPCRs show several conserved allosteric communication pipelines from the residues in the agonist binding site with the G-protein interface. Positions of the residues along these pipelines that serve as major hubs of allosteric communication are conserved in their respective structures. These findings have important implications in understanding the dynamics and allosteric mechanism of communication in class A GPCRs and hence are useful for designing conformation-specific drugs.
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Affiliation(s)
- Supriyo Bhattacharya
- Beckman Research Institute, City of Hope National Medical Center , 1500 Duarte Road, Duarte, California 91010, United States
| | - Romelia Salomon-Ferrer
- Beckman Research Institute, City of Hope National Medical Center , 1500 Duarte Road, Duarte, California 91010, United States
| | - Sangbae Lee
- Beckman Research Institute, City of Hope National Medical Center , 1500 Duarte Road, Duarte, California 91010, United States
| | - Nagarajan Vaidehi
- Beckman Research Institute, City of Hope National Medical Center , 1500 Duarte Road, Duarte, California 91010, United States
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Hamilton JR, Trejo J. Challenges and Opportunities in Protease-Activated Receptor Drug Development. Annu Rev Pharmacol Toxicol 2016; 57:349-373. [PMID: 27618736 DOI: 10.1146/annurev-pharmtox-011613-140016] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protease-activated receptors (PARs) are a unique class of G protein-coupled receptors (GPCRs) that transduce cellular responses to extracellular proteases. PARs have important functions in the vasculature, inflammation, and cancer and are important drug targets. A unique feature of PARs is their irreversible proteolytic mechanism of activation that results in the generation of a tethered ligand that cannot diffuse away. Despite the fact that GPCRs have proved to be the most successful class of druggable targets, the development of agents that target PARs specifically has been challenging. As a consequence, researchers have taken a remarkable diversity of approaches to develop pharmacological entities that modulate PAR function. Here, we present an overview of the diversity of therapeutic agents that have been developed against PARs. We further discuss PAR biased signaling and the influence of receptor compartmentalization, posttranslational modifications, and dimerization, which are important considerations for drug development.
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Affiliation(s)
- Justin R Hamilton
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria 3004, Australia
| | - JoAnn Trejo
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093;
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G Protein-Coupled Receptors in Cancer. Int J Mol Sci 2016; 17:ijms17081320. [PMID: 27529230 PMCID: PMC5000717 DOI: 10.3390/ijms17081320] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/21/2016] [Accepted: 08/08/2016] [Indexed: 12/12/2022] Open
Abstract
Despite the fact that G protein-coupled receptors (GPCRs) are the largest signal-conveying receptor family and mediate many physiological processes, their role in tumor biology is underappreciated. Numerous lines of evidence now associate GPCRs and their downstream signaling targets in cancer growth and development. Indeed, GPCRs control many features of tumorigenesis, including immune cell-mediated functions, proliferation, invasion and survival at the secondary site. Technological advances have further substantiated GPCR modifications in human tumors. Among these are point mutations, gene overexpression, GPCR silencing by promoter methylation and the number of gene copies. At this point, it is imperative to elucidate specific signaling pathways of “cancer driver” GPCRs. Emerging data on GPCR biology point to functional selectivity and “biased agonism”; hence, there is a diminishing enthusiasm for the concept of “one drug per GPCR target” and increasing interest in the identification of several drug options. Therefore, determining the appropriate context-dependent conformation of a functional GPCR as well as the contribution of GPCR alterations to cancer development remain significant challenges for the discovery of dominant cancer genes and the development of targeted therapeutics.
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Castaldi A, Chesini GP, Taylor AE, Sussman MA, Brown JH, Purcell NH. Sphingosine 1-phosphate elicits RhoA-dependent proliferation and MRTF-A mediated gene induction in CPCs. Cell Signal 2016; 28:871-9. [PMID: 27094722 PMCID: PMC5004781 DOI: 10.1016/j.cellsig.2016.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 04/01/2016] [Accepted: 04/10/2016] [Indexed: 12/16/2022]
Abstract
Although c-kit(+) cardiac progenitor cells (CPCs) are currently used in clinical trials there remain considerable gaps in our understanding of the molecular mechanisms underlying their proliferation and differentiation. G-protein coupled receptors (GPCRs) play an important role in regulating these processes in mammalian cell types thus we assessed GPCR mRNA expression in c-kit(+) cells isolated from adult mouse hearts. Our data provide the first comprehensive overview of the distribution of this fundamental class of cardiac receptors in CPCs and reveal notable distinctions from that of adult cardiomyocytes. We focused on GPCRs that couple to RhoA activation in particular those for sphingosine-1-phosphate (S1P). The S1P2 and S1P3 receptors are the most abundant S1P receptor subtypes in mouse and human CPCs while cardiomyocytes express predominantly S1P1 receptors. Treatment of CPCs with S1P, as with thrombin and serum, increased proliferation through a pathway requiring RhoA signaling, as evidenced by significant attenuation when Rho was inhibited by treatment with C3 toxin. Further analysis demonstrated that both S1P- and serum-induced proliferation are regulated through the S1P2 and S1P3 receptor subtypes which couple to Gα12/13 to elicit RhoA activation. The transcriptional co-activator MRTF-A was activated by S1P as assessed by its nuclear accumulation and induction of a RhoA/MRTF-A luciferase reporter. In addition S1P treatment increased expression of cardiac lineage markers Mef2C and GATA4 and the smooth muscle marker GATA6 through activation of MRTF-A. In conclusion, we delineate an S1P-regulated signaling pathway in CPCs that introduces the possibility of targeting S1P2/3 receptors, Gα12/13 or RhoA to influence the proliferation and commitment of c-kit(+) CPCs and improve the response of the myocardium following injury.
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Affiliation(s)
- Alessandra Castaldi
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA
| | - Gino P Chesini
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA
| | - Amy E Taylor
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA
| | - Mark A Sussman
- San Diego State Heart Institute, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Joan Heller Brown
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA.
| | - Nicole H Purcell
- Department of Pharmacology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA
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Lin C, von der Thüsen J, Isermann B, Weiler H, van der Poll T, Borensztajn K, Spek CA. High endogenous activated protein C levels attenuates bleomycin-induced pulmonary fibrosis. J Cell Mol Med 2016; 20:2029-2035. [PMID: 27295971 PMCID: PMC5082406 DOI: 10.1111/jcmm.12891] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/02/2016] [Indexed: 01/13/2023] Open
Abstract
Coagulation activation accompanied by reduced anticoagulant activity is a key characteristic of patients with idiopathic pulmonary fibrosis (IPF). Although the importance of coagulation activation in IPF is well studied, the potential relevance of endogenous anticoagulant activity in IPF progression remains elusive. We assess the importance of the endogenous anticoagulant protein C pathway on disease progression during bleomycin‐induced pulmonary fibrosis. Wild‐type mice and mice with high endogenous activated protein C APC levels (APChigh) were subjected to bleomycin‐induced pulmonary fibrosis. Fibrosis was assesses by hydroxyproline and histochemical analysis. Macrophage recruitment was assessed immunohistochemically. In vitro, macrophage migration was analysed by transwell migration assays. Fourteen days after bleomycin instillation, APChigh mice developed pulmonary fibrosis to a similar degree as wild‐type mice. Interestingly, Aschcroft scores as well as lung hydroxyproline levels were significantly lower in APChigh mice than in wild‐type mice on day 28. The reduction in fibrosis in APChigh mice was accompanied by reduced macrophage numbers in their lungs and subsequent in vitro experiments showed that APC inhibits thrombin‐dependent macrophage migration. Our data suggest that high endogenous APC levels inhibit the progression of bleomycin‐induced pulmonary fibrosis and that APC modifies pulmonary fibrosis by limiting thrombin‐dependent macrophage recruitment.
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Affiliation(s)
- Cong Lin
- Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Jan von der Thüsen
- Department of Pathology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Berend Isermann
- Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany
| | - Hartmut Weiler
- Department of Physiology, BloodCenter of Wisconsin, Milwaukee, WI, USA
| | - Tom van der Poll
- Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Keren Borensztajn
- Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands.,Inserm UMR1152, Medical School Xavier Bichat, Paris, France.,Département Hospitalo-universtaire FIRE (Fibrosis Inflammation and Remodeling) and LabEx Inflamex, Paris, France
| | - Chris A Spek
- Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
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Systematic analysis of factors influencing observations of biased agonism at the mu-opioid receptor. Biochem Pharmacol 2016; 113:70-87. [PMID: 27286929 DOI: 10.1016/j.bcp.2016.05.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/31/2016] [Indexed: 11/24/2022]
Abstract
Biased agonism describes the ability of distinct G protein-coupled receptor (GPCR) ligands to stabilise distinct receptor conformations leading to the activation of different cell signalling pathways that can deliver different physiologic outcomes. This phenomenon is having a major impact on modern drug discovery as it offers the potential to design ligands that selectively activate or inhibit the signalling pathways linked to therapeutic effects with minimal activation or blockade of signalling pathways that are linked to the development of adverse on-target effects. However, the explosion in studies of biased agonism at multiple GPCR families in recombinant cell lines has revealed a high degree of variability on descriptions of biased ligands at the same GPCR and raised the question of whether biased agonism is a fixed attribute of a ligand in all cell types. The current study addresses this question at the mu-opioid receptor (MOP). Here, we have systematically assessed the impact of differential cellular protein complement (and cellular background), signalling kinetics and receptor species on our previous descriptions of biased agonism at MOP by several opioid peptides and synthetic opioids. Our results show that all these factors need to be carefully determined and reported when considering biased agonism. Nevertheless, our studies also show that, despite changes in overall signalling profiles, ligands that previously showed distinct bias profiles at MOP retained their uniqueness across different cell backgrounds.
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Chandler KB, Costello CE. Glycomics and glycoproteomics of membrane proteins and cell-surface receptors: Present trends and future opportunities. Electrophoresis 2016; 37:1407-19. [PMID: 26872045 PMCID: PMC4889498 DOI: 10.1002/elps.201500552] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/02/2016] [Accepted: 02/02/2016] [Indexed: 12/16/2022]
Abstract
Membrane proteins mediate cell-cell interactions and adhesion, the transfer of ions and metabolites, and the transmission of signals from the extracellular environment to the cell interior. The extracellular domains of most cell membrane proteins are glycosylated, often at multiple sites. There is a growing awareness that glycosylation impacts the structure, interaction, and function of membrane proteins. The application of glycoproteomics and glycomics methods to membrane proteins has great potential. However, challenges also arise from the unique physical properties of membrane proteins. Successful analytical workflows must be developed and disseminated to advance functional glycoproteomics and glycomics studies of membrane proteins. This review explores the opportunities and challenges related to glycomic and glycoproteomic analysis of membrane proteins, including discussion of sample preparation, enrichment, and MS/MS analyses, with a focus on recent successful workflows for analysis of N- and O-linked glycosylation of mammalian membrane proteins.
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Affiliation(s)
- Kevin Brown Chandler
- Center for Biomedical Mass Spectrometry, Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Catherine E Costello
- Center for Biomedical Mass Spectrometry, Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
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40
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Abstract
Protease signaling in cells elicits multiple physiologically important responses via protease-activated receptors (PARs). There are 4 members of this family of G-protein-coupled receptors (PAR1-4). PARs are activated by proteolysis of the N terminus to reveal a tethered ligand. The rate-limiting step of PAR signaling is determined by the efficiency of proteolysis of the N terminus, which is regulated by allosteric binding sites, cofactors, membrane localization, and receptor dimerization. This ultimately controls the initiation of PAR signaling. In addition, these factors also control the cellular response by directing signaling toward G-protein or β-arrestin pathways. PAR1 signaling on endothelial cells is controlled by the activating protease and heterodimerization with PAR2 or PAR3. As a consequence, the genetic and epigenetic control of PARs and their cofactors in physiologic and pathophysiologic conditions have the potential to influence cellular behavior. Recent studies have uncovered polymorphisms that result in PAR4 sequence variants with altered reactivity that interact to influence platelet response. This further demonstrates how interactions within the plasma membrane can control the physiological output. Understanding the structural rearrangement following PAR activation and how PARs are allosterically controlled within the plasma membrane will determine how best to target this family of receptors therapeutically. The purpose of this article is to review how signaling from PARs is influenced by alternative cleavage sites and the physical interactions within the membrane. Going forward, it will be important to relate the altered signaling to the molecular arrangement of PARs in the cell membrane and to determine how these may be influenced genetically.
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41
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Kleist AB, Getschman AE, Ziarek JJ, Nevins AM, Gauthier PA, Chevigné A, Szpakowska M, Volkman BF. New paradigms in chemokine receptor signal transduction: Moving beyond the two-site model. Biochem Pharmacol 2016; 114:53-68. [PMID: 27106080 DOI: 10.1016/j.bcp.2016.04.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022]
Abstract
Chemokine receptor (CKR) signaling forms the basis of essential immune cellular functions, and dysregulated CKR signaling underpins numerous disease processes of the immune system and beyond. CKRs, which belong to the seven transmembrane domain receptor (7TMR) superfamily, initiate signaling upon binding of endogenous, secreted chemokine ligands. Chemokine-CKR interactions are traditionally described by a two-step/two-site mechanism, in which the CKR N-terminus recognizes the chemokine globular core (i.e. site 1 interaction), followed by activation when the unstructured chemokine N-terminus is inserted into the receptor TM bundle (i.e. site 2 interaction). Several recent studies challenge the structural independence of sites 1 and 2 by demonstrating physical and allosteric links between these supposedly separate sites. Others contest the functional independence of these sites, identifying nuanced roles for site 1 and other interactions in CKR activation. These developments emerge within a rapidly changing landscape in which CKR signaling is influenced by receptor PTMs, chemokine and CKR dimerization, and endogenous non-chemokine ligands. Simultaneous advances in the structural and functional characterization of 7TMR biased signaling have altered how we understand promiscuous chemokine-CKR interactions. In this review, we explore new paradigms in CKR signal transduction by considering studies that depict a more intricate architecture governing the consequences of chemokine-CKR interactions.
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Affiliation(s)
- Andrew B Kleist
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Anthony E Getschman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Joshua J Ziarek
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, MA 02115, USA.
| | - Amanda M Nevins
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Pierre-Arnaud Gauthier
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Andy Chevigné
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Martyna Szpakowska
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Marada S, Navarro G, Truong A, Stewart DP, Arensdorf AM, Nachtergaele S, Angelats E, Opferman JT, Rohatgi R, McCormick PJ, Ogden SK. Functional Divergence in the Role of N-Linked Glycosylation in Smoothened Signaling. PLoS Genet 2015; 11:e1005473. [PMID: 26291458 PMCID: PMC4546403 DOI: 10.1371/journal.pgen.1005473] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 07/28/2015] [Indexed: 01/06/2023] Open
Abstract
The G protein-coupled receptor (GPCR) Smoothened (Smo) is the requisite signal transducer of the evolutionarily conserved Hedgehog (Hh) pathway. Although aspects of Smo signaling are conserved from Drosophila to vertebrates, significant differences have evolved. These include changes in its active sub-cellular localization, and the ability of vertebrate Smo to induce distinct G protein-dependent and independent signals in response to ligand. Whereas the canonical Smo signal to Gli transcriptional effectors occurs in a G protein-independent manner, its non-canonical signal employs Gαi. Whether vertebrate Smo can selectively bias its signal between these routes is not yet known. N-linked glycosylation is a post-translational modification that can influence GPCR trafficking, ligand responsiveness and signal output. Smo proteins in Drosophila and vertebrate systems harbor N-linked glycans, but their role in Smo signaling has not been established. Herein, we present a comprehensive analysis of Drosophila and murine Smo glycosylation that supports a functional divergence in the contribution of N-linked glycans to signaling. Of the seven predicted glycan acceptor sites in Drosophila Smo, one is essential. Loss of N-glycosylation at this site disrupted Smo trafficking and attenuated its signaling capability. In stark contrast, we found that all four predicted N-glycosylation sites on murine Smo were dispensable for proper trafficking, agonist binding and canonical signal induction. However, the under-glycosylated protein was compromised in its ability to induce a non-canonical signal through Gαi, providing for the first time evidence that Smo can bias its signal and that a post-translational modification can impact this process. As such, we postulate a profound shift in N-glycan function from affecting Smo ER exit in flies to influencing its signal output in mice. N-linked glycosylation is a post-translational modification occurring on membrane proteins such as G protein-coupled receptors (GPCR). Smoothened (Smo) is a GPCR that functions as the signal transducer of the Hedgehog (Hh) pathway. We used a mutagenesis approach to assess the role of N-glycans in Smo signaling in two genetic models for Hh pathway activity, Drosophila and mouse. In doing so, we discovered a divergence in glycan function between them. We mapped an essential N-glycan acceptor site that when lost in Drosophila, triggered ER retention, altered Smo protein stability and blunted its signaling capacity. Conversely, ER exit of the murine protein was unaffected by glycan loss, as was its ability to traffic and induce a G protein-independent signal to activate Hh target genes. However, the ability of vertebrate Smo to induce a distinct G protein-dependent signal was lost. This suggests that N-linked glycosylation may influence signal bias of vertebrate Smo to favor one signal output over the other. We therefore propose that the role of this conserved post-translational modification may have been repurposed from governing Smo ER exit in the fly to influencing effector route selection in vertebrates.
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Affiliation(s)
- Suresh Marada
- Department of Cell & Molecular Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Gemma Navarro
- Department of Biochemistry and Molecular Biology, Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)University of Barcelona, Barcelona, Spain
| | - Ashley Truong
- Department of Cell & Molecular Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- Summer Plus Program, Rhodes College, Memphis, Tennessee, United States of America
| | - Daniel P. Stewart
- Department of Cell & Molecular Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Angela M. Arensdorf
- Department of Cell & Molecular Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Sigrid Nachtergaele
- Departments of Medicine and Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Edgar Angelats
- Department of Biochemistry and Molecular Biology, Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)University of Barcelona, Barcelona, Spain
| | - Joseph T. Opferman
- Department of Cell & Molecular Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Rajat Rohatgi
- Departments of Medicine and Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Peter J. McCormick
- Department of Biochemistry and Molecular Biology, Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)University of Barcelona, Barcelona, Spain
- School of Pharmacy, University of East Anglia, Norwich, Norfolk, United Kingdom
| | - Stacey K. Ogden
- Department of Cell & Molecular Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- * E-mail:
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