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Liu Q, Meng X, Song Z, Shao Y, Zhao Y, Fang R, Huo Y, Zhang L. Insect-transmitted plant virus balances its vertical transmission through regulating Rab1-mediated receptor localization. Cell Rep 2024; 43:114571. [PMID: 39093698 DOI: 10.1016/j.celrep.2024.114571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 06/23/2024] [Accepted: 07/17/2024] [Indexed: 08/04/2024] Open
Abstract
Rice stripe virus (RSV) establishes infection in the ovaries of its vector insect, Laodelphax striatellus. We demonstrate that RSV infection delays ovarian maturation by inhibiting membrane localization of the vitellogenin receptor (VgR), thereby reducing the vitellogenin (Vg) accumulation essential for egg development. We identify the host protein L. striatellus Rab1 protein (LsRab1), which directly interacts with RSV nucleocapsid protein (NP) within nurse cells. LsRab1 is required for VgR surface localization and ovarian Vg accumulation. RSV inhibits LsRab1 function through two mechanisms: NP binding LsRab1 prevents GTP binding, and NP binding LsRab1-GTP complexes stimulates GTP hydrolysis, forming an inactive LsRab1 form. Through this dual inhibition, RSV infection prevents LsRab1 from facilitating VgR trafficking to the cell membrane, leading to inefficient Vg uptake. The Vg-VgR pathway is present in most oviparous animals, and the mechanisms detailed here provide insights into the vertical transmission of other insect-transmitted viruses of medical and agricultural importance.
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Affiliation(s)
- Qing Liu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangyi Meng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyu Song
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Ying Shao
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, Shanxi Province 030801, China
| | - Yao Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Rongxiang Fang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Huo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lili Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.
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2
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Gironacci MM, Bruna-Haupt E. Unraveling the crosstalk between renin-angiotensin system receptors. Acta Physiol (Oxf) 2024; 240:e14134. [PMID: 38488216 DOI: 10.1111/apha.14134] [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: 01/12/2024] [Revised: 02/23/2024] [Accepted: 03/05/2024] [Indexed: 04/24/2024]
Abstract
The renin-angiotensin system (RAS) plays a key role in blood pressure regulation. The RAS is a complex interconnected system composed of two axes with opposite effects. The pressor arm, represented by angiotensin (Ang) II and the AT1 receptor (AT1R), mediates the vasoconstrictor, proliferative, hypertensive, oxidative, and pro-inflammatory effects of the RAS, while the depressor/protective arm, represented by Ang-(1-7), its Mas receptor (MasR) and the AT2 receptor (AT2R), opposes the actions elicited by the pressor arm. The AT1R, AT2R, and MasR belong to the G-protein-coupled receptor (GPCR) family. GPCRs operate not only as monomers, but they can also function in dimeric (homo and hetero) or higher-order oligomeric states. Due to the interaction with other receptors, GPCR properties may change: receptor affinity, trafficking, signaling, and its biological function may be altered. Thus, heteromerization provides a newly recognized means of modulation of receptor function, as well as crosstalk between GPCRs. This review is focused on angiotensin receptors, and how their properties are influenced by crosstalk with other receptors, adding more complexity to an already complex system and potentially opening up new therapeutic approaches.
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Affiliation(s)
- Mariela M Gironacci
- Facultad de Farmacia y Bioquímica, IQUIFIB (UBA-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ezequiel Bruna-Haupt
- INTEQUI (CONICET), Departamento de Química, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina
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3
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Herrera A, Packer MM, Rosas-Lemus M, Minasov G, Brummel JH, Satchell KJF. Vibrio MARTX toxin processing and degradation of cellular Rab GTPases by the cytotoxic effector Makes Caterpillars Floppy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537381. [PMID: 37131655 PMCID: PMC10153396 DOI: 10.1101/2023.04.19.537381] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Vibrio vulnificus causes life threatening infections dependent upon the effectors released from the Multifunctional-Autoprocessing Repeats-In-Toxin (MARTX) toxin. The Makes Caterpillars Floppy-like (MCF) cysteine protease effector is activated by host ADP ribosylation factors (ARFs), although the targets of processing activity were unknown. In this study we show MCF binds Ras-related proteins in brain (Rab) GTPases at the same interface occupied by ARFs and then cleaves and/or degrades 24 distinct members of the Rab GTPases family. The cleavage occurs in the C-terminal tails of Rabs. We determine the crystal structure of MCF as a swapped dimer revealing the open, activated state of MCF and then use structure prediction algorithms to show that structural composition, rather than sequence or localization, determine Rabs selected as MCF proteolytic targets. Once cleaved, Rabs become dispersed in cells to drive organelle damage and cell death to promote pathogenesis of these rapidly fatal infections.
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Affiliation(s)
- Alfa Herrera
- Department of Microbiology-Immunology and Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Megan M. Packer
- Department of Microbiology-Immunology and Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Monica Rosas-Lemus
- Department of Microbiology-Immunology and Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - George Minasov
- Department of Microbiology-Immunology and Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - John H. Brummel
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- SickKids IBD Centre, The Hospital for Sick Children, Toronto, ON, Canada
| | - Karla J. F. Satchell
- Department of Microbiology-Immunology and Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Center for Structural Biology of Infectious Diseases, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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4
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Gyurkovska V, Murtazina R, Zhao SF, Shikano S, Okamoto Y, Segev N. Dual function of Rab1A in secretion and autophagy: hypervariable domain dependence. Life Sci Alliance 2023; 6:e202201810. [PMID: 36781179 PMCID: PMC9939007 DOI: 10.26508/lsa.202201810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/15/2023] Open
Abstract
We currently understand how the different intracellular pathways, secretion, endocytosis, and autophagy are regulated by small GTPases. In contrast, it is unclear how these pathways are coordinated to ensure efficient cellular response to stress. Rab GTPases localize to specific organelles through their hypervariable domain (HVD) to regulate discrete steps of individual pathways. Here, we explored the dual role of Rab1A/B (92% identity) in secretion and autophagy. We show that although either Rab1A or Rab1B is required for secretion, Rab1A, but not Rab1B, localizes to autophagosomes and is required early in stress-induced autophagy. Moreover, replacing the HVD of Rab1B with that of Rab1A enables Rab1B to localize to autophagosomes and regulate autophagy. Therefore, Rab1A-HVD is required for the dual functionality of a single Rab in two different pathways: secretion and autophagy. In addition to this mechanistic insight, these findings are relevant to human health because both the pathways and Rab1A/B were implicated in diseases ranging from cancer to neurodegeneration.
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Affiliation(s)
- Valeriya Gyurkovska
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Rakhilya Murtazina
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Sarah F Zhao
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Sojin Shikano
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Yukari Okamoto
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Nava Segev
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
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5
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Johnstone EKM, Ayoub MA, Hertzman RJ, See HB, Abhayawardana RS, Seeber RM, Pfleger KDG. Novel Pharmacology Following Heteromerization of the Angiotensin II Type 2 Receptor and the Bradykinin Type 2 Receptor. Front Endocrinol (Lausanne) 2022; 13:848816. [PMID: 35721749 PMCID: PMC9204302 DOI: 10.3389/fendo.2022.848816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/21/2022] [Indexed: 01/18/2023] Open
Abstract
The angiotensin type 2 (AT2) receptor and the bradykinin type 2 (B2) receptor are G protein-coupled receptors (GPCRs) that have major roles in the cardiovascular system. The two receptors are known to functionally interact at various levels, and there is some evidence that the observed crosstalk may occur as a result of heteromerization. We investigated evidence for heteromerization of the AT2 receptor and the B2 receptor in HEK293FT cells using various bioluminescence resonance energy transfer (BRET)-proximity based assays, including the Receptor Heteromer Investigation Technology (Receptor-HIT) and the NanoBRET ligand-binding assay. The Receptor-HIT assay showed that Gαq, GRK2 and β-arrestin2 recruitment proximal to AT2 receptors only occurred upon B2 receptor coexpression and activation, all of which is indicative of AT2-B2 receptor heteromerization. Additionally, we also observed specific coupling of the B2 receptor with the Gαz protein, and this was found only in cells coexpressing both receptors and stimulated with bradykinin. The recruitment of Gαz, Gαq, GRK2 and β-arrestin2 was inhibited by B2 receptor but not AT2 receptor antagonism, indicating the importance of B2 receptor activation within AT2-B2 heteromers. The close proximity between the AT2 receptor and B2 receptor at the cell surface was also demonstrated with the NanoBRET ligand-binding assay. Together, our data demonstrate functional interaction between the AT2 receptor and B2 receptor in HEK293FT cells, resulting in novel pharmacology for both receptors with regard to Gαq/GRK2/β-arrestin2 recruitment (AT2 receptor) and Gαz protein coupling (B2 receptor). Our study has revealed a new mechanism for the enigmatic and poorly characterized AT2 receptor to be functionally active within cells, further illustrating the role of heteromerization in the diversity of GPCR pharmacology and signaling.
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Affiliation(s)
- Elizabeth K. M. Johnstone
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
- *Correspondence: Elizabeth K. M. Johnstone, ; Kevin D. G. Pfleger,
| | - Mohammed Akli Ayoub
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Rebecca J. Hertzman
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Heng B. See
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Rekhati S. Abhayawardana
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Ruth M. Seeber
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Kevin D. G. Pfleger
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, WA, Australia
- *Correspondence: Elizabeth K. M. Johnstone, ; Kevin D. G. Pfleger,
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6
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Zhang W, Wang Y, Li C, Xu Y, Wang X, Wu D, Gao Z, Qian H, You Z, Zhang Z, He B, Wang G. Extracellular CIRP-Impaired Rab26 Restrains EPOR-Mediated Macrophage Polarization in Acute Lung Injury. Front Immunol 2021; 12:768435. [PMID: 34925338 PMCID: PMC8671298 DOI: 10.3389/fimmu.2021.768435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/09/2021] [Indexed: 12/31/2022] Open
Abstract
Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a condition with an imbalanced inflammatory response and delayed resolution of inflammation. Macrophage polarization plays an important role in inflammation and resolution. However, the mechanism of macrophage polarization in ALI/ARDS is not fully understood. We found that mice with lipopolysaccharide administration developed lung injury with the accumulation of extracellular cold-inducible RNA-binding protein (eCIRP) in the lungs. eCIRP, as a damage-associated molecular pattern (DAMP), inhibited M2 macrophage polarization, thereby tipping the balance toward inflammation rather than resolution. Anti-CIRP antibodies reversed such phenotypes. The levels of macrophage erythropoietin (EPO) receptor (EPOR) were reduced after eCIRP treatment. Myeloid-specific EPOR-deficient mice displayed restrained M2 macrophage polarization and impaired inflammation resolution. Mechanistically, eCIRP impaired Rab26, a member of Ras superfamilies of small G proteins, and reduced the transportation of surface EPOR, which resulted in macrophage polarization toward the M1 phenotype. Moreover, EPO treatment hardly promotes M2 polarization in Rab26 knockout (KO) macrophages through EPOR. Collectively, macrophage EPOR signaling is impaired by eCIRP through Rab26 during ALI/ARDS, leading to the restrained M2 macrophage polarization and delayed inflammation resolution. These findings identify a mechanism of persistent inflammation and a potential therapy during ALI/ARDS.
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Affiliation(s)
- Wen Zhang
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Yao Wang
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Chuanwei Li
- Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yu Xu
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Xia Wang
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Di Wu
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Zhan Gao
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Hang Qian
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Zaichun You
- Department of General Practice, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Zhiren Zhang
- Institute of Immunology, Third Military Medical University, Chongqing, China
| | - Binfeng He
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China.,Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Guansong Wang
- Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing, China
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7
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Johnstone EKM, See HB, Abhayawardana RS, Song A, Rosengren KJ, Hill SJ, Pfleger KDG. Investigation of Receptor Heteromers Using NanoBRET Ligand Binding. Int J Mol Sci 2021; 22:1082. [PMID: 33499147 PMCID: PMC7866079 DOI: 10.3390/ijms22031082] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 12/20/2022] Open
Abstract
Receptor heteromerization is the formation of a complex involving at least two different receptors with pharmacology that is distinct from that exhibited by its constituent receptor units. Detection of these complexes and monitoring their pharmacology is crucial for understanding how receptors function. The Receptor-Heteromer Investigation Technology (Receptor-HIT) utilizes ligand-dependent modulation of interactions between receptors and specific biomolecules for the detection and profiling of heteromer complexes. Previously, the interacting biomolecules used in Receptor-HIT assays have been intracellular proteins, however in this study we have for the first time used bioluminescence resonance energy transfer (BRET) with fluorescently-labeled ligands to investigate heteromerization of receptors on the cell surface. Using the Receptor-HIT ligand binding assay with NanoBRET, we have successfully investigated heteromers between the angiotensin II type 1 (AT1) receptor and the β2 adrenergic receptor (AT1-β2AR heteromer), as well as between the AT1 and angiotensin II type 2 receptor (AT1-AT2 heteromer).
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Affiliation(s)
- Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Canberra, NSW 2609, Australia
| | - Heng B. See
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Canberra, NSW 2609, Australia
| | - Rekhati S. Abhayawardana
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Canberra, NSW 2609, Australia
| | - Angela Song
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD 4072, Australia; (A.S.); (K.J.R.)
| | - K. Johan Rosengren
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD 4072, Australia; (A.S.); (K.J.R.)
| | - Stephen J. Hill
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham Medical School, Nottingham NG7 2UH, UK
- Centre of Membrane Proteins and Receptors, University of Nottingham, Midlands NG7 2UH, UK
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology Group, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; (H.B.S.); (R.S.A.); (S.J.H.)
- Centre for Medical Research, The University of Western Australia, Crawley, WA 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Canberra, NSW 2609, Australia
- Dimerix Limited, Nedlands, WA 6009, Australia
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8
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Zhang M, Wu G. Mechanisms of the anterograde trafficking of GPCRs: Regulation of AT1R transport by interacting proteins and motifs. Traffic 2018; 20:110-120. [PMID: 30426616 DOI: 10.1111/tra.12624] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/29/2018] [Accepted: 11/08/2018] [Indexed: 12/11/2022]
Abstract
Anterograde cell surface transport of nascent G protein-coupled receptors (GPCRs) en route from the endoplasmic reticulum (ER) through the Golgi apparatus represents a crucial checkpoint to control the amount of the receptors at the functional destination and the strength of receptor activation-elicited cellular responses. However, as compared with extensively studied internalization and recycling processes, the molecular mechanisms of cell surface trafficking of GPCRs are relatively less defined. Here, we will review the current advances in understanding the ER-Golgi-cell surface transport of GPCRs and use angiotensin II type 1 receptor as a representative GPCR to discuss emerging roles of receptor-interacting proteins and specific motifs embedded within the receptors in controlling the forward traffic of GPCRs along the biosynthetic pathway.
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Affiliation(s)
- Maoxiang Zhang
- Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
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9
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Hammad MM, Dunn HA, Ferguson SSG. MAGI proteins can differentially regulate the signaling pathways of 5-HT 2AR by enhancing receptor trafficking and PLC recruitment. Cell Signal 2018; 47:109-121. [PMID: 29625175 DOI: 10.1016/j.cellsig.2018.03.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/28/2018] [Accepted: 03/28/2018] [Indexed: 12/31/2022]
Abstract
MAGI proteins are Membrane-Associated Guanylate Kinase Inverted proteins that belong to the MAGUK family. They are scaffolding proteins that were shown to mediate the trafficking and signaling of various G protein-coupled receptors (GPCRs). They contain PDZ domains in their structure and many GPCRs interact with these proteins via the PDZ motifs on the carboxyl terminal end of a receptor. In a PDZ overlay assay performed with the carboxyl terminal tail of 5-HT2AR, we were able to detect all three members of the MAGI subfamily, MAGI-1, MAGI-2 and MAGI-3 as interacting PDZ proteins. The PDZ motif of 5-HT2AR consists of three amino acids; serine (S), cysteine (C) and valine (V). In this study, we characterize these 5-HT2AR interactions with MAGI proteins. We first confirm the interaction using co-immunopricipitation and illustrate that the interaction is PDZ motif-dependent in human embryonic kidney (HEK 293) cells. We then assess the effects of overexpression and knockdown of the MAGI proteins on the internalization, trafficking and signaling of 5-HT2AR. We find that knockdown of either MAGI-1 or MAGI-3 using siRNA results in a significant reduction in the internalization of 5-HT2AR. As for signaling, we report here that MAGI proteins can modulate the signaling via the two transduction pathways that 5-HT2AR can activate. We illustrate a significant effect of modulating MAGI proteins expression on 5-HT-stimulated IP formation. We demonstrate an enhancement in 5-HT2AR-stimulated IP formation upon MAGI proteins overexpression. In addition, we show that knockdown of MAGI proteins with siRNA leads to a significant reduction in 5-HT2AR-stimulated IP formation. Furthermore, we illustrate a significant increase in 5-HT-stimulated ERK1/2 phosphorylation upon MAGI proteins knockdown. Interestingly, this effect on ERK1/2 activation is PDZ motif-independent. We also suggest two possible mechanisms of regulation for the effect of MAGI proteins on 5-HT2AR function. One mechanism involves the regulation of cell surface expression since we show that both MAGI-2 and MAGI-3 can enhance receptor trafficking to the plasma membrane when overexpressed in HEK 293 cells. The other mechanism points to regulation of second messengers in the signaling pathways. Specifically, we show that overexpression of any of the three MAGI proteins can enhance the recruitment of PLCβ3 to 5-HT2AR. In addition, we report a negative effect for knocking down MAGI-3 on β-arrestin recruitment to the receptor and this effect is PDZ motif-independent. Taken together, our findings document distinct roles for the three MAGI proteins in regulating 5-HT2AR trafficking and signaling and emphasize the importance of studying PDZ proteins and their interactions with GPCRs to regulate their function.
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Affiliation(s)
- Maha M Hammad
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Dr., Ottawa, Ontario K1H 8M5, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Henry A Dunn
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Dr., Ottawa, Ontario K1H 8M5, Canada
| | - Stephen S G Ferguson
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Dr., Ottawa, Ontario K1H 8M5, Canada.
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10
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Wang G, Wei Z, Wu G. Role of Rab GTPases in the export trafficking of G protein-coupled receptors. Small GTPases 2018; 9:130-135. [PMID: 28125329 PMCID: PMC5902197 DOI: 10.1080/21541248.2016.1277000] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/12/2016] [Accepted: 12/21/2016] [Indexed: 12/11/2022] Open
Abstract
G protein-coupled receptors (GPCRs) constitute a superfamily of cell surface receptors that regulate a variety of cell functions. As the cell surface is the functional destination for most GPCRs, the cell surface targeting process represents a crucial checkpoint in controlling the functionality of the receptors. However, the molecular mechanisms underlying the cell surface delivery of newly synthesized GPCRs remain poorly understood. In this review, we will highlight the role of Rab GTPases in GPCR cell surface transport, particularly post-Golgi traffic, and discuss the underlying molecular mechanisms.
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Affiliation(s)
- Guansong Wang
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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11
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Angiotensin II type 2 receptor (AT2R) in renal and cardiovascular disease. Clin Sci (Lond) 2017; 130:1307-26. [PMID: 27358027 DOI: 10.1042/cs20160243] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/06/2016] [Indexed: 12/14/2022]
Abstract
Angiotensin II (Ang II) is well-considered to be the principal effector of the renin-angiotensin system (RAS), which binds with strong affinity to the angiotensin II type 1 (AT1R) and type 2 (AT2R) receptor subtype. However, activation of both receptors is likely to stimulate different signalling mechanisms/pathways and produce distinct biological responses. The haemodynamic and non-haemodynamic effects of Ang II, including its ability to regulate blood pressure, maintain water-electrolyte balance and promote vasoconstriction and cellular growth are well-documented to be mediated primarily by the AT1R. However, its biological and functional effects mediated through the AT2R subtype are still poorly understood. Recent studies have emphasized that activation of the AT2R regulates tissue and organ development and provides in certain context a potential counter-regulatory mechanism against AT1R-mediated actions. Thus, this review will focus on providing insights into the biological role of the AT2R, in particular its actions within the renal and cardiovascular system.
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Teng Y, Qin H, Bahassan A, Bendzunas NG, Kennedy EJ, Cowell JK. The WASF3-NCKAP1-CYFIP1 Complex Is Essential for Breast Cancer Metastasis. Cancer Res 2016; 76:5133-42. [PMID: 27432794 DOI: 10.1158/0008-5472.can-16-0562] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/25/2016] [Indexed: 12/20/2022]
Abstract
Inactivation of the WASF3 gene suppresses invasion and metastasis of breast cancer cells. WASF3 function is regulated through a protein complex that includes the NCKAP1 and CYFIP1 proteins. Here, we report that silencing NCKAP1 destabilizes the WASF3 complex, resulting in a suppression of the invasive capacity of breast, prostate, and colon cancer cells. In an in vivo model of spontaneous metastasis in immunocompromized mice, loss of NCKAP1 also suppresses metastasis. Activation of the WASF protein complex occurs through interaction with RAC1, and inactivation of NCKAP1 prevents the association of RAC1 with the WASF3 complex. Thus, WASF3 depends on NCKAP1 to promote invasion and metastasis. Here, we show that stapled peptides targeting the interface between NCKAP1 and CYFIP1 destabilize the WASF3 complex and suppress RAC1 binding, thereby suppressing invasion. Using a complex-disrupting compound identified in this study termed WANT3, our results offer a mechanistic proof of concept to target this interaction as a novel approach to inhibit breast cancer metastasis. Cancer Res; 76(17); 5133-42. ©2016 AACR.
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Affiliation(s)
- Yong Teng
- Department of Oral Biology, Augusta University, Augusta, Georgia. Georgia Cancer Center, Augusta University, Augusta, Georgia.
| | - Haiyan Qin
- Georgia Cancer Center, Augusta University, Augusta, Georgia
| | | | - N George Bendzunas
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia
| | - Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia.
| | - John K Cowell
- Georgia Cancer Center, Augusta University, Augusta, Georgia.
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Zhu S, Zhang M, Davis JE, Wu WH, Surrao K, Wang H, Wu G. A single mutation in helix 8 enhances the angiotensin II type 1a receptor transport and signaling. Cell Signal 2015; 27:2371-9. [PMID: 26342563 DOI: 10.1016/j.cellsig.2015.08.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 08/30/2015] [Indexed: 01/01/2023]
Abstract
The amphipathic helix 8 in the membrane-proximal C-terminus is a structurally conserved feature of class A seven transmembrane-spanning G protein-coupled receptors (GPCRs). Mutations of this helical motif often cause receptor misfolding, defective cell surface transport and dysfunction. Surprisingly, we demonstrated here that a single point mutation at Lys308 in helix 8 markedly enhanced the steady-state surface density of the angiotensin II type 1a receptor (AT1aR). Consistent with the enhanced cell surface expression, Lys308 mutation significantly augmented AT1aR-mediated mitogen-activated protein kinase ERK1/2 activation, inositol phosphate production, and vascular smooth muscle cell migration. This mutation also increased the overall expression of AT1aR without altering receptor degradation. More interestingly, Lys308 mutation abolished AT1aR interaction with β-COP, a component of COPI transport vesicles, and impaired AT1aR responsiveness to the inhibition of Rab6 GTPase involved in the Golgi-to-ER retrograde pathway. Furthermore, these functions of Lys308 were largely dependent on its positively charged property. These data reveal previously unappreciated functions of helix 8 and novel mechanisms governing the cell surface transport and function of AT1aR.
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Affiliation(s)
- Shu Zhu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - Maoxiang Zhang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - Jason E Davis
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - William H Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - Kristen Surrao
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - Hong Wang
- School of Life Sciences and Technology, Tongji University, 1239 Siping Road, Shanghai, China
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States.
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Tadevosyan A, Villeneuve LR, Fournier A, Chatenet D, Nattel S, Allen BG. Caged ligands to study the role of intracellular GPCRs. Methods 2015. [PMID: 26196333 DOI: 10.1016/j.ymeth.2015.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In addition to cell surface membranes, numerous G protein-coupled receptors (GPCRs) are located on intracellular membranes including the nuclear envelope. Although the role of numerous GPCRs at the cell surface has been well characterized, the physiological function of these same receptors located on intracellular membranes remains to be determined. Here, we employ a novel caged Ang-II analog, cAng-II, to compare the effects of the activation of cell surface versus intracellular angiotensin receptors in intact cardiomyocytes. When added extracellularly to HEK 293 cells, Ang-II and photolysed cAng-II increased ERK1/2 phosphorylation (via AT1R) and cGMP production (AT2R). In contrast unphotolysed cAng-II did not. Cellular uptake of cAng-II was 6-fold greater than that of Ang-II and comparable to the HIV TAT(48-60) peptide. Intracellular photolysis of cAng-II induced an increase in nucleoplasmic Ca(2+) ([Ca(2+)]n) that was greater than that induced by extracellular application of Ang-II. We conclude that cell-permeable ligands that can access intracellular GPCRs may evoke responses distinct from those with access restricted to the same receptor located on the cell surface.
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Affiliation(s)
- Artavazd Tadevosyan
- Department of Medicine, Université de Montréal, Canada; Montreal Heart Institute, Canada
| | | | - Alain Fournier
- INRS-Institut Armand-Frappier, Université du Québec, Canada; Laboratoire International Associé Samuel de Champlain, Canada
| | - David Chatenet
- INRS-Institut Armand-Frappier, Université du Québec, Canada; Laboratoire International Associé Samuel de Champlain, Canada
| | - Stanley Nattel
- Department of Medicine, Université de Montréal, Canada; Montreal Heart Institute, Canada; Department of Pharmacology and Therapeutics, McGill University, Canada.
| | - Bruce G Allen
- Department of Medicine, Université de Montréal, Canada; Montreal Heart Institute, Canada; Department of Pharmacology and Therapeutics, McGill University, Canada; Department of Biochemistry and Molecular Medicine, Université de Montréal, Canada.
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15
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Tadevosyan A, Létourneau M, Folch B, Doucet N, Villeneuve LR, Mamarbachi AM, Pétrin D, Hébert TE, Fournier A, Chatenet D, Allen BG, Nattel S. Photoreleasable ligands to study intracrine angiotensin II signalling. J Physiol 2015; 593:521-39. [PMID: 25433071 DOI: 10.1113/jphysiol.2014.279109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 11/20/2014] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS The renin-angiotensin system plays a key role in cardiovascular physiology and its overactivation has been implicated in the pathogenesis of several major cardiovascular diseases. There is growing evidence that angiotensin II (Ang-II) may function as an intracellular peptide to activate intracellular/nuclear receptors and their downstream signalling effectors independently of cell surface receptors. Current methods used to study intracrine Ang-II signalling are limited to indirect approaches because of a lack of selective intracellularly-acting probes. Here, we present novel photoreleasable Ang-II analogues used to probe intracellular actions with spatial and temporal precision. The photorelease of intracellular Ang-II causes nuclear and cytosolic calcium mobilization and initiates the de novo synthesis of RNA in cardiac cells, demonstrating the application of the method. ABSTRACT Several lines of evidence suggest that intracellular angiotensin II (Ang-II) contributes to the regulation of cardiac contractility, renal salt reabsorption, vascular tone and metabolism; however, work on intracrine Ang-II signalling has been limited to indirect approaches because of a lack of selective intracellularly-acting probes. Here, we aimed to synthesize and characterize cell-permeant Ang-II analogues that are inactive without uncaging, but release active Ang-II upon exposure to a flash of UV-light, and act as novel tools for use in the study of intracrine Ang-II physiology. We prepared three novel caged Ang-II analogues, [Tyr(DMNB)(4)]Ang-II, Ang-II-ODMNB and [Tyr(DMNB)(4)]Ang-II-ODMNB, based upon the incorporation of the photolabile moiety 4,5-dimethoxy-2-nitrobenzyl (DMNB). Compared to Ang-II, the caged Ang-II analogues showed 2-3 orders of magnitude reduced affinity toward both angiotensin type-1 (AT1R) and type-2 (AT2R) receptors in competition binding assays, and greatly-reduced potency in contraction assays of rat thoracic aorta. After receiving UV-irradiation, all three caged Ang-II analogues released Ang-II and potently induced the contraction of rat thoracic aorta. [Tyr(DMNB)(4)]Ang-II showed the most rapid photolysis upon UV-irradiation and was the focus of subsequent characterization. Whereas Ang-II and photolysed [Tyr(DMNB)(4)]Ang-II increased ERK1/2 phosphorylation (via AT1R) and cGMP production (AT2R), caged [Tyr(DMNB)(4)]Ang-II did not. Cellular uptake of [Tyr(DMNB)(4)]Ang-II was 4-fold greater than that of Ang-II and significantly greater than uptake driven by the positive-control HIV TAT(48-60) peptide. Intracellular photolysis of [Tyr(DMNB)(4)]Ang-II induced an increase in nucleoplasmic Ca(2+) ([Ca(2+)]n), and initiated 18S rRNA and nuclear factor kappa B mRNA synthesis in adult cardiac cells. We conclude that caged Ang-II analogues represent powerful new tools for use in the selective study of intracrine signalling via Ang-II.
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Affiliation(s)
- Artavazd Tadevosyan
- Department of Medicine, Université de Montréal, Montréal, Québec, Canada; Montreal Heart Institute, Montréal, Québec, Canada
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Wu G, Davis JE, Zhang M. Regulation of α2B-Adrenerigc Receptor Export Trafficking by Specific Motifs. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 132:227-44. [PMID: 26055061 PMCID: PMC4827153 DOI: 10.1016/bs.pmbts.2015.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Intracellular trafficking and precise targeting to specific locations of G protein-coupled receptors (GPCRs) control the physiological functions of the receptors. Compared to the extensive efforts dedicated to understanding the events involved in the endocytic and recycling pathways, the molecular mechanisms underlying the transport of the GPCR superfamily from the endoplasmic reticulum (ER) through the Golgi to the plasma membrane are relatively less well defined. Over the past years, we have used α(2B)-adrenergic receptor (α(2B)-AR) as a model to define the factors that control GPCR export trafficking. In this chapter, we will review specific motifs identified to mediate the export of nascent α(2B)-AR from the ER and the Golgi and discuss the possible underlying mechanisms. As these motifs are highly conserved among GPCRs, they may provide common mechanisms for export trafficking of these receptors.
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Affiliation(s)
- Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA.
| | - Jason E Davis
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
| | - Maoxiang Zhang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
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17
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Goupil E, Fillion D, Clément S, Luo X, Devost D, Sleno R, Pétrin D, Saragovi HU, Thorin É, Laporte SA, Hébert TE. Angiotensin II type I and prostaglandin F2α receptors cooperatively modulate signaling in vascular smooth muscle cells. J Biol Chem 2014; 290:3137-48. [PMID: 25512374 DOI: 10.1074/jbc.m114.631119] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The angiotensin II type I (AT1R) and the prostaglandin F2α (PGF2α) F prostanoid (FP) receptors are both potent regulators of blood pressure. Physiological interplay between AT1R and FP has been described. Abdominal aortic ring contraction experiments revealed that PGF2α-dependent activation of FP potentiated angiotensin II-induced contraction, whereas FP antagonists had the opposite effect. Similarly, PGF2α-mediated vasoconstriction was symmetrically regulated by co-treatment with AT1R agonist and antagonist. The underlying canonical Gαq signaling via production of inositol phosphates mediated by each receptor was also regulated by antagonists for the other receptor. However, binding to their respective agonists, regulation of receptor-mediated MAPK activation and vascular smooth muscle cell growth were differentially or asymmetrically regulated depending on how each of the two receptors were occupied by either agonist or antagonist. Physical interactions between these receptors have never been reported, and here we show that AT1R and FP form heterodimeric complexes in both HEK 293 and vascular smooth muscle cells. These findings imply that formation of the AT1R/FP dimer creates a novel allosteric signaling unit that shows symmetrical and asymmetrical signaling behavior, depending on the outcome measured. AT1R/FP dimers may thus be important in the regulation of blood pressure.
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Affiliation(s)
- Eugénie Goupil
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Dany Fillion
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Stéphanie Clément
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Xiaoyan Luo
- the Centre de Recherche, Institut de Cardiologie de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Dominic Devost
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Rory Sleno
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - Darlaine Pétrin
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6
| | - H Uri Saragovi
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, the Lady Davis Institute, Montréal Jewish General Hospital, Montréal, Québec H3T 1E2, and
| | - Éric Thorin
- the Centre de Recherche, Institut de Cardiologie de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Stéphane A Laporte
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, the Department of Medicine, McGill University Health Center Research Institute, Montréal, Québec H3A 2B2, the Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0CT,
| | - Terence E Hébert
- From the Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6,
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18
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Tao YX, Conn PM. Chaperoning G protein-coupled receptors: from cell biology to therapeutics. Endocr Rev 2014; 35:602-47. [PMID: 24661201 PMCID: PMC4105357 DOI: 10.1210/er.2013-1121] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 03/14/2014] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors (GPCRs) are membrane proteins that traverse the plasma membrane seven times (hence, are also called 7TM receptors). The polytopic structure of GPCRs makes the folding of GPCRs difficult and complex. Indeed, many wild-type GPCRs are not folded optimally, and defects in folding are the most common cause of genetic diseases due to GPCR mutations. Both general and receptor-specific molecular chaperones aid the folding of GPCRs. Chemical chaperones have been shown to be able to correct the misfolding in mutant GPCRs, proving to be important tools for studying the structure-function relationship of GPCRs. However, their potential therapeutic value is very limited. Pharmacological chaperones (pharmacoperones) are potentially important novel therapeutics for treating genetic diseases caused by mutations in GPCR genes that resulted in misfolded mutant proteins. Pharmacoperones also increase cell surface expression of wild-type GPCRs; therefore, they could be used to treat diseases that do not harbor mutations in GPCRs. Recent studies have shown that indeed pharmacoperones work in both experimental animals and patients. High-throughput assays have been developed to identify new pharmacoperones that could be used as therapeutics for a number of endocrine and other genetic diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology, and Pharmacology (Y.-X.T.), College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849-5519; and Departments of Internal Medicine and Cell Biology (P.M.C.), Texas Tech University Health Science Center, Lubbock, Texas 79430-6252
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Bertuccio CA, Lee SL, Wu G, Butterworth MB, Hamilton KL, Devor DC. Anterograde trafficking of KCa3.1 in polarized epithelia is Rab1- and Rab8-dependent and recycling endosome-independent. PLoS One 2014; 9:e92013. [PMID: 24632741 PMCID: PMC3954861 DOI: 10.1371/journal.pone.0092013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/16/2014] [Indexed: 02/01/2023] Open
Abstract
The intermediate conductance, Ca2+-activated K+ channel (KCa3.1) targets to the basolateral (BL) membrane in polarized epithelia where it plays a key role in transepithelial ion transport. However, there are no studies defining the anterograde and retrograde trafficking of KCa3.1 in polarized epithelia. Herein, we utilize Biotin Ligase Acceptor Peptide (BLAP)-tagged KCa3.1 to address these trafficking steps in polarized epithelia, using MDCK, Caco-2 and FRT cells. We demonstrate that KCa3.1 is exclusively targeted to the BL membrane in these cells when grown on filter supports. Following endocytosis, KCa3.1 degradation is prevented by inhibition of lysosomal/proteosomal pathways. Further, the ubiquitylation of KCa3.1 is increased following endocytosis from the BL membrane and PR-619, a deubiquitylase inhibitor, prevents degradation, indicating KCa3.1 is targeted for degradation by ubiquitylation. We demonstrate that KCa3.1 is targeted to the BL membrane in polarized LLC-PK1 cells which lack the μ1B subunit of the AP-1 complex, indicating BL targeting of KCa3.1 is independent of μ1B. As Rabs 1, 2, 6 and 8 play roles in ER/Golgi exit and trafficking of proteins to the BL membrane, we evaluated the role of these Rabs in the trafficking of KCa3.1. In the presence of dominant negative Rab1 or Rab8, KCa3.1 cell surface expression was significantly reduced, whereas Rabs 2 and 6 had no effect. We also co-immunoprecipitated KCa3.1 with both Rab1 and Rab8. These results suggest these Rabs are necessary for the anterograde trafficking of KCa3.1. Finally, we determined whether KCa3.1 traffics directly to the BL membrane or through recycling endosomes in MDCK cells. For these studies, we used either recycling endosome ablation or dominant negative RME-1 constructs and determined that KCa3.1 is trafficked directly to the BL membrane rather than via recycling endosomes. These results are the first to describe the anterograde and retrograde trafficking of KCa3.1 in polarized epithelia cells.
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Affiliation(s)
- Claudia A. Bertuccio
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Shih-Liang Lee
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, Otago, New Zealand
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
| | - Michael B. Butterworth
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Kirk L. Hamilton
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, Otago, New Zealand
- * E-mail: (DCD); (KLH)
| | - Daniel C. Devor
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (DCD); (KLH)
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Zhang X, Wang H, Duvernay MT, Zhu S, Wu G. The angiotensin II type 1 receptor C-terminal Lys residues interact with tubulin and modulate receptor export trafficking. PLoS One 2013; 8:e57805. [PMID: 23451270 PMCID: PMC3581488 DOI: 10.1371/journal.pone.0057805] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 01/25/2013] [Indexed: 12/15/2022] Open
Abstract
The physiological and pathological functions of angiotensin II are largely mediated through activating the cell surface angiotensin II type 1 receptor (AT1R). However, the molecular mechanisms underlying the transport of newly synthesized AT1R from the endoplasmic reticulum (ER) to the cell surface remain poorly defined. Here we demonstrated that the C-terminus (CT) of AT1R directly and strongly bound to tubulin and the binding domains were mapped to two consecutive Lys residues at positions 310 and 311 in the CT membrane-proximal region of AT1R and the acidic CT of tubulin, suggestive of essentially ionic interactions between AT1R and tubulin. Furthermore, mutation to disrupt tubulin binding dramatically inhibited the cell surface expression of AT1R, arrested AT1R in the ER, and attenuated AT1R-mediated signaling measured as ERK1/2 activation. These data demonstrate for the first time that specific Lys residues in the CT juxtamembrane region regulate the processing of AT1R through interacting with tubulin. These data also suggest an important role of the microtubule network in the cell surface transport of AT1R.
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Affiliation(s)
- Xiaoping Zhang
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Hong Wang
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
- School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Matthew T. Duvernay
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Shu Zhu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
| | - Guangyu Wu
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
- * E-mail:
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Abstract
In addition to heterotrimeric G-proteins, Ras-like small GTPases are also involved in regulating physiological functions of the G-protein-coupled receptor (GPCR) superfamily. In particular, Rab and ARF GTPases function either as "traffic cops" to coordinate receptor targeting to specific locations or as "signal transducers" to directly mediate receptor signal propagation. As revealed in protein-protein interaction assays, GPCRs may use specific motifs to physically interact with small GTPases, providing important insights into the underlying molecular mechanisms. In this chapter, we describe coimmunoprecipitation and GST fusion protein pull-down approaches to study the GPCR-small GTPase interaction, by focusing on the interaction of α(2B)- and β(2)-adrenegic receptors with the small GTPases Rab8 and ARF1.
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Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, USA
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Lachance V, Degrandmaison J, Marois S, Robitaille M, Génier S, Nadeau S, Angers S, Parent JL. Ubiquitination and activation of a Rab GTPase promoted by a β2-Adrenergic Receptor/HACE1 complex. J Cell Sci 2013; 127:111-23. [DOI: 10.1242/jcs.132944] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We and others have shown that trafficking of G protein-coupled receptors is regulated by Rab GTPases. Cargo-mediated regulation of vesicular transport has received great attention lately. Rab GTPases, forming the largest branch of the Ras GTPase superfamily, regulate almost every step of vesicle-mediated trafficking. Rab GTPases are well-recognized targets of human diseases but their regulation and the mechanisms connecting them to cargo proteins are still poorly understood. Herein, we show by overexpression/depletion studies that HACE1, a HECT domain-containing ubiquitin ligase, promotes the recycling of the β2-adrenergic receptor (β2AR), a prototypical G protein-coupled receptor, through a Rab11a-dependent mechanism. Interestingly, the β2AR in conjunction with HACE1 triggered ubiquitination of Rab11a, as observed by Western blot analysis. LC-MS/MS experiments determined that Rab11a is ubiquitnatied on Lys145. A Rab11a-K145R mutant failed to undergo β2AR/HACE1-induced ubiquitination and inhibited the HACE1-mediated recycling of the β2AR. Rab11a, but not Rab11a-K145R, was activated by β2AR/HACE1 indicating that ubiquitination of Lys145 is involved in Rab11a activation. β2AR/HACE1 co-expression also potentiated ubiquitination of Rab6a and Rab8a, but not of other Rab GTPases that were tested. We report a novel regulatory mechanism of Rab GTPases by their ubiquitination with associated functional effects demonstrated on Rab11a. This partakes into a new pathway whereby a cargo protein, like a G protein-coupled receptor, can regulate its own trafficking by inducing the ubiquitination and activation of a Rab GTPase.
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Anterograde trafficking of nascent α(2B)-adrenergic receptor: structural basis, roles of small GTPases. CURRENT TOPICS IN MEMBRANES 2012; 67:79-100. [PMID: 21771486 DOI: 10.1016/b978-0-12-384921-2.00004-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
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Abstract
Anterograde trafficking of newly synthesized G protein-coupled -receptors (GPCRs) from the endoplasmic reticulum to the cell surface represents a crucial checkpoint in controlling the amount of the functional receptors at the cell surface and the strength of signaling initiated by the receptors. In contrast to the extensively studied, well-understood endocytic and recycling pathways, the molecular mechanisms underlying the cell-surface targeting of the receptors remain poorly defined. In this chapter, I will discuss current advances in understanding post-Golgi transport of GPCRs by focusing on specific motifs or sequences that may function as sorting signals regulating export from the Golgi and subsequent transport to the plasma membrane of GPCRs.
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Wang G, Wu G. Small GTPase regulation of GPCR anterograde trafficking. Trends Pharmacol Sci 2011; 33:28-34. [PMID: 22015208 DOI: 10.1016/j.tips.2011.09.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/15/2011] [Accepted: 09/19/2011] [Indexed: 01/14/2023]
Abstract
The physiological functions of heterotrimeric G protein-coupled receptors (GPCRs) are dictated by their intracellular trafficking and precise targeting to the functional destinations. Over the past decades, most studies on the trafficking of GPCRs have focused on the events involved in endocytosis and recycling. By contrast, the molecular mechanisms underlying anterograde transport of newly synthesized GPCRs from the endoplasmic reticulum (ER) to the cell surface have only now begun to be revealed. In this review we discuss current advances in understanding the role of Ras-like GTPases, specifically the Rab and Sar1/ARF subfamilies, in regulating cell-surface transport of GPCRs en route from the ER and the Golgi.
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Affiliation(s)
- Guansong Wang
- Institute of Respiratory Diseases, Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, China
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26
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Abstract
BACKGROUND Angiotensin II (Ang II) induces constriction (AT(1)) and dilation (AT(2) receptors) of cerebral arterioles. High sodium intake induces changes in receptors expression and loss of AT(2)-mediated vasodilation in extracerebral vessels. We investigated whether high salt modifies the AT(2)-mediated response of cerebral arterioles. METHODS Three-month-old male Wistar rats received drinking water supplemented or not with 1% NaCl. We measured at day 4 or 30 plasma aldosterone concentration, AT receptors expression (brain microvessels, western blot, RT-qPCR), internal diameter of pial arterioles (cranial window) following suffusion with Ang II (10(-6) mol/l, or 10(-8) mol/l + losartan 10(-5) mol/l), serotonin (5-HT, 10(-6) mol/l), sodium nitroprusside (10(-5) mol/l) and adenosine diphosphate (ADP, 10(-4) mol/l). RESULTS High salt did not modify arterial pressure, baseline arteriolar diameter, vasoconstriction to Ang II or 5-HT, nor vasodilation to SNP. High salt lowered plasma aldosterone concentration (d4 138 ± 71 not significant vs. control 338 ± 73; d30 150 ± 21 P < 0.05 vs. control 517 ± 79 μmol/l). AT receptors mRNA did not change while protein level of AT(2) receptors decreased at d4 (64 ± 9% of control, P < 0.05). AT(2)-mediated vasodilation (control d4; d30 8 ± 2; 5 ± 2%) was abolished at d4 (-2 ± 2%, P < 0.05) and reversed to vasoconstriction at d30 (-7 ± 2%, P < 0.05). ADP-induced vasodilation is abolished at d30 (2 ± 2, P < 0.05 vs. control 19 ± 4%). CONCLUSION High salt specifically abolishes AT(2)-mediated vasodilation, immediately, via decreased level of AT(2) receptor protein, and after 30 days, in association with abolition of endothelial vasodilation. Such loss of AT(2)-mediated vasodilation may be deleterious in case of stroke.
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Lachance V, Cartier A, Génier S, Munger S, Germain P, Labrecque P, Parent JL. Regulation of β2-adrenergic receptor maturation and anterograde trafficking by an interaction with Rab geranylgeranyltransferase: modulation of Rab geranylgeranylation by the receptor. J Biol Chem 2011; 286:40802-13. [PMID: 21990357 DOI: 10.1074/jbc.m111.267815] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Previous reports by us and others demonstrated that G protein-coupled receptors interact functionally with Rab GTPases. Here, we show that the β(2)-adrenergic receptor (β(2)AR) interacts with the Rab geranylgeranyltransferase α-subunit (RGGTA). Confocal microscopy showed that β(2)AR co-localizes with RGGTA in intracellular compartments and at the plasma membrane. Site-directed mutagenesis revealed that RGGTA binds to the L(339)L(340) motif in the β(2)AR C terminus known to be involved in the transport of the receptor from the endoplasmic reticulum to the cell surface. Modulation of the cellular levels of RGGTA protein by overexpression or siRNA-mediated knockdown of the endogenous protein demonstrated that RGGTA has a positive role in the maturation and anterograde trafficking of the β(2)AR, which requires the interaction of RGGTA with the β(2)AR L(339)L(340) motif. Furthermore, the β(2)AR modulates the geranylgeranylation of Rab6a, Rab8a, and Rab11a, but not of other Rab proteins tested in this study. Regulation of Rab geranylgeranylation by the β(2)AR was dependent on the RGGTA-interacting L(339)L(340) motif. Interestingly, a RGGTA-Y107F mutant was unable to regulate Rab geranylgeranylation but still promoted β(2)AR maturation, suggesting that RGGTA may have functions independent of Rab geranylgeranylation. We demonstrate for the first time an interaction between a transmembrane receptor and RGGTA which regulates the maturation and anterograde transport of the receptor, as well as geranylgeranylation of Rab GTPases.
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Affiliation(s)
- Véronik Lachance
- Service de Rhumatologie, Département de Médecine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, the Centre de Recherche Clinique Étienne-Le Bel, and the Institut de Pharmacologie de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
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Zhang X, Dong C, Wu QJ, Balch WE, Wu G. Di-acidic motifs in the membrane-distal C termini modulate the transport of angiotensin II receptors from the endoplasmic reticulum to the cell surface. J Biol Chem 2011; 286:20525-35. [PMID: 21507945 DOI: 10.1074/jbc.m111.222034] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The molecular mechanisms underlying the endoplasmic reticulum (ER) export and cell surface transport of nascent G protein-coupled receptors (GPCRs) have just begun to be revealed and previous studies have shown that hydrophobic motifs in the putative amphipathic 8(th) α-helical region within the membrane-proximal C termini play an important role. In this study, we demonstrate that di-acidic motifs in the membrane-distal, nonstructural C-terminal portions are required for the exit from the ER and transport to the plasma membrane of angiotensin II receptors, but not adrenergic receptors. More interestingly, distinct di-acidic motifs dictate optimal export trafficking of different angiotensin II receptors and export ability of each acidic residue in the di-acidic motifs cannot be fully substituted by other acidic residue. Moreover, the function of the di-acidic motifs is likely mediated through facilitating the recruitment of the receptors onto the ER-derived COPII transport vesicles. Therefore, the di-acidic motifs located in the membrane-distal C termini may represent the first linear motifs which recruit selective GPCRs onto the COPII vesicles to control their export from the ER.
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Affiliation(s)
- Xiaoping Zhang
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
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Duvernay MT, Wang H, Dong C, Guidry JJ, Sackett DL, Wu G. Alpha2B-adrenergic receptor interaction with tubulin controls its transport from the endoplasmic reticulum to the cell surface. J Biol Chem 2011; 286:14080-9. [PMID: 21357695 DOI: 10.1074/jbc.m111.222323] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
It is well recognized that the C terminus (CT) plays a crucial role in modulating G protein-coupled receptor (GPCR) transport from the endoplasmic reticulum (ER) to the cell surface. However the molecular mechanisms that govern CT-dependent ER export remain elusive. To address this issue, we used α(2B)-adrenergic receptor (α(2B)-AR) as a model GPCR to search for proteins interacting with the CT. By using peptide-conjugated affinity matrix combined with proteomics and glutathione S-transferase fusion protein pull-down assays, we identified tubulin directly interacting with the α(2B)-AR CT. The interaction domains were mapped to the acidic CT of tubulin and the basic Arg residues in the α(2B)-AR CT, particularly Arg-437, Arg-441, and Arg-446. More importantly, mutation of these Arg residues to disrupt tubulin interaction markedly inhibited α(2B)-AR transport to the cell surface and strongly arrested the receptor in the ER. These data provide the first evidence indicating that the α(2B)-AR C-terminal Arg cluster mediates its association with tubulin to coordinate its ER-to-cell surface traffic and suggest a novel mechanism of GPCR export through physical contact with microtubules.
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Affiliation(s)
- Matthew T Duvernay
- From the Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
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Zhuang X, Adipietro KA, Datta S, Northup JK, Ray K. Rab1 small GTP-binding protein regulates cell surface trafficking of the human calcium-sensing receptor. Endocrinology 2010; 151:5114-23. [PMID: 20861236 PMCID: PMC2954715 DOI: 10.1210/en.2010-0422] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The human calcium-sensing receptor (hCaR) is a family-3/C G-protein-coupled receptor that regulates Ca(2+) homeostasis by controlling parathyroid hormone secretion. Here we investigated the role of Rab1, a small GTP-binding protein that specifically regulates protein transport from the endoplasmic reticulum to the Golgi, in cell surface transport of the hCaR. Cell surface expression of hCaR transiently expressed in human embryonic kidney 293 cells was strongly augmented by coexpression of Rab1 and attenuated by disruption of endogenous Rab1 function by expression of the dominant-negative Rab1N124I mutant or depletion of Rab1 with small interfering RNA. Rab1N124I expression also partially attenuated cell surface expression and signaling response to gain-of-function mutants of hCaR with truncated carboxyl-terminal sequences at positions 895 and 903. These carboxyl-tail truncations are similar to a deletion between residues S895 and V1075 found in a patient family causing autosomal dominant hypocalcemia. In addition, coexpression with wild-type Rab1 increased cell surface expression of the loss-of-function missense mutation R185Q, located on the hCaR amino-terminal extracellular ligand-binding domain (ECD), which causes familial hypocalciuric hypercalcemia. Truncated hCaR variants containing either the ECD with the first transmembrane helix or only the ECD also display Rab1-dependent cell surface expression or secretion into the culture medium, respectively. These data reveal a role for Rab1 in hCaR trafficking from the endoplasmic reticulum to the Golgi that regulates receptor cell surface expression and thereby cell signaling responsiveness to extracellular calcium.
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Affiliation(s)
- Xiaolei Zhuang
- Laboratory of Cellular Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892, USA
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Wang G, Zhang Z, Xu Z, Yin H, Bai L, Ma Z, Decoster MA, Qian G, Wu G. Activation of the sonic hedgehog signaling controls human pulmonary arterial smooth muscle cell proliferation in response to hypoxia. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:1359-67. [PMID: 20840857 DOI: 10.1016/j.bbamcr.2010.09.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 03/14/2010] [Revised: 08/27/2010] [Accepted: 09/01/2010] [Indexed: 12/16/2022]
Abstract
The hedgehog signal pathway plays a crucial role in the angiogenesis and vascular remodeling. However, the function of this pathway in the pulmonary vascular smooth cell proliferation in response to hypoxia remains unknown. In this study, we have demonstrated that the main components of the hedgehog pathway, including sonic hedgehog (SHH), patched1 (PTCH1), smoothened (SMO), GLI and hypoxia-inducible factor 1 (HIF1) are expressed in the human pulmonary arterial smooth muscle cells (HPASMCs). Interestingly, hypoxia significantly enhanced the expression of SHH and HIF1, facilitated the translocation of GLI1 into the nuclei, and promoted the proliferation of HPASMCs. Furthermore, direct activation of the SHH pathway through incubation with the purified recombinant human SHH or with purmorphamine and SAG, two Smo agonists, also enhanced the proliferation of HPASMCs. Importantly, the treatment with anti-SHH and anti-HIF1 antibodies or cyclopamine, a specific SMO inhibitor, markedly inhibited the nuclear translocation of GLI1 and cell proliferation in the HPASMCs induced by hypoxia and activation of the SHH pathway. Moreover, the treatment with cyclopamine increased apoptosis in the hypoxic HPASMCs. These data strongly demonstrate for the first time that the SHH signaling plays a crucial role in the regulation of HPASMC growth in response to hypoxia.
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Affiliation(s)
- Guansong Wang
- Institute of Respiratory Diseases, Xinqiao Hospital of the Third Military Medical University, Chongqing 400037, P.R. China; Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
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Dong C, Yang L, Zhang X, Gu H, Lam ML, Claycomb WC, Xia H, Wu G. Rab8 interacts with distinct motifs in alpha2B- and beta2-adrenergic receptors and differentially modulates their transport. J Biol Chem 2010; 285:20369-80. [PMID: 20424170 DOI: 10.1074/jbc.m109.081521] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The molecular mechanism underlying the post-Golgi transport of G protein-coupled receptors (GPCRs) remains poorly understood. Here we determine the role of Rab8 GTPase, which modulates vesicular protein transport between the trans-Golgi network (TGN) and the plasma membrane, in the cell surface targeting of alpha(2B)- and beta(2)-adrenergic receptors (AR). Transient expression of GDP- and GTP-bound Rab8 mutants and short hairpin RNA-mediated knockdown of Rab8 more potently inhibited the cell surface expression of alpha(2B)-AR than beta(2)-AR. The GDP-bound Rab8(T22N) mutant attenuated ERK1/2 activation by alpha(2B)-AR, but not beta(2)-AR, and arrested alpha(2B)-AR in the TGN compartment. Co-immunoprecipitation revealed that both alpha(2B)-AR and beta(2)-AR physically interacted with Rab8 and glutathione S-transferase fusion protein pulldown assays demonstrated that Rab8 interacted with the C termini of both receptors. Interestingly, mutation of the highly conserved membrane-proximal C terminus dileucine motif selectively blocked beta(2)-AR interaction with Rab8, whereas mutation of residues Val(431)-Phe(432)-Asn(433)-Gln(434), Pro(447)-Trp(448), Gln(450)-Thr(451), and Trp(453) in the C terminus impaired alpha(2B)-AR interaction with Rab8. Furthermore, transport inhibition by Rab8(T22N) of a chimeric beta(2)-AR carrying the alpha(2B)-AR C terminus was similar to alpha(2B)-AR. These data provide strong evidence indicating that Rab8 GTPase interacts with distinct motifs in the C termini of alpha(2B)-AR and beta(2)-AR and differentially modulates their traffic from the TGN to the cell surface.
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Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
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Dong C, Zhang X, Zhou F, Dou H, Duvernay MT, Zhang P, Wu G. ADP-ribosylation factors modulate the cell surface transport of G protein-coupled receptors. J Pharmacol Exp Ther 2010; 333:174-83. [PMID: 20093398 DOI: 10.1124/jpet.109.161489] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
ADP-ribosylation factors (ARFs) regulate vesicular traffic through recruiting coat proteins. However, their functions in the anterograde transport of nascent G protein-coupled receptors (GPCRs) from the endoplasmic reticulum to the plasma membrane remain poorly explored. Here we show that treatment with brefeldin A, an inhibitor of guanine nucleotide exchange on ARFs, markedly attenuated the cell surface numbers of alpha(2B)-adrenergic receptor (AR), beta(2)-AR, angiotensin II type 1 receptor, and chemokine (CXC motif) receptor 4. Functional inhibition of individual ARF GTPases by transient expression of the GDP-bound, GTP-bound, and guanine nucleotide-deficient mutants showed that the five human ARFs differentially modulated receptor cell surface expression and that the ARF1 mutants produced the most profound inhibitory effect. Furthermore, expression of the ARF1 GTPase-activating protein (GAP) ARFGAP1 significantly blocked receptor transport. Interestingly, the GDP- and GTP-bound ARF1 mutants arrested the receptors in distinct intracellular compartments. Consistent with the reduced receptor cell surface expression, extracellular signal-regulated kinase 1 and 2 activation by receptor agonists was significantly attenuated by the GDP-bound mutant ARF1T31N. Moreover, coimmunoprecipitation showed that alpha(2B)-AR associated with ARF1 and glutathione transferase pull-down assay indicated that the alpha(2B)-AR C terminus directly interacted with ARF1. These data show that ARF1 GTPase is involved in the regulation of cell surface expression of GPCRs at multiple transport steps.
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Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, LA 70112, USA
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