1
|
Mavri M, Glišić S, Senćanski M, Vrecl M, Rosenkilde MM, Spiess K, Kubale V. Patterns of human and porcine gammaherpesvirus-encoded BILF1 receptor endocytosis. Cell Mol Biol Lett 2023; 28:14. [PMID: 36810008 PMCID: PMC9942385 DOI: 10.1186/s11658-023-00427-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/30/2023] [Indexed: 02/23/2023] Open
Abstract
BACKGROUND The viral G-protein-coupled receptor (vGPCR) BILF1 encoded by the Epstein-Barr virus (EBV) is an oncogene and immunoevasin and can downregulate MHC-I molecules at the surface of infected cells. MHC-I downregulation, which presumably occurs through co-internalization with EBV-BILF1, is preserved among BILF1 receptors, including the three BILF1 orthologs encoded by porcine lymphotropic herpesviruses (PLHV BILFs). This study aimed to understand the detailed mechanisms of BILF1 receptor constitutive internalization, to explore the translational potential of PLHV BILFs compared with EBV-BILF1. METHODS A novel real-time fluorescence resonance energy transfer (FRET)-based internalization assay combined with dominant-negative variants of dynamin-1 (Dyn K44A) and the chemical clathrin inhibitor Pitstop2 in HEK-293A cells was used to study the effect of specific endocytic proteins on BILF1 internalization. Bioluminescence resonance energy transfer (BRET)-saturation analysis was used to study BILF1 receptor interaction with β-arrestin2 and Rab7. In addition, a bioinformatics approach informational spectrum method (ISM) was used to investigate the interaction affinity of BILF1 receptors with β-arrestin2, AP-2, and caveolin-1. RESULTS We identified dynamin-dependent, clathrin-mediated constitutive endocytosis for all BILF1 receptors. The observed interaction affinity between BILF1 receptors and caveolin-1 and the decreased internalization in the presence of a dominant-negative variant of caveolin-1 (Cav S80E) indicated the involvement of caveolin-1 in BILF1 trafficking. Furthermore, after BILF1 internalization from the plasma membrane, both the recycling and degradation pathways are proposed for BILF1 receptors. CONCLUSIONS The similarity in the internalization mechanisms observed for EBV-BILF1 and PLHV1-2 BILF1 provide a foundation for further studies exploring a possible translational potential for PLHVs, as proposed previously, and provides new information about receptor trafficking.
Collapse
Affiliation(s)
- Maša Mavri
- Institute for preclinical sciences, Veterinary Faculty, Ljubljana, Slovenia
| | - Sanja Glišić
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Milan Senćanski
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Milka Vrecl
- Institute for preclinical sciences, Veterinary Faculty, Ljubljana, Slovenia
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Katja Spiess
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Virus and Microbiological Special Diagnostics, Statens Serum Institute, Copenhagen, Denmark
| | - Valentina Kubale
- Institute for preclinical sciences, Veterinary Faculty, Ljubljana, Slovenia.
| |
Collapse
|
2
|
Bychkova VE, Dolgikh DA, Balobanov VA, Finkelstein AV. The Molten Globule State of a Globular Protein in a Cell Is More or Less Frequent Case Rather than an Exception. Molecules 2022; 27:molecules27144361. [PMID: 35889244 PMCID: PMC9319461 DOI: 10.3390/molecules27144361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/01/2022] [Accepted: 07/03/2022] [Indexed: 02/01/2023] Open
Abstract
Quite a long time ago, Oleg B. Ptitsyn put forward a hypothesis about the possible functional significance of the molten globule (MG) state for the functioning of proteins. MG is an intermediate between the unfolded and the native state of a protein. Its experimental detection and investigation in a cell are extremely difficult. In the last decades, intensive studies have demonstrated that the MG-like state of some globular proteins arises from either their modifications or interactions with protein partners or other cell components. This review summarizes such reports. In many cases, MG was evidenced to be functionally important. Thus, the MG state is quite common for functional cellular proteins. This supports Ptitsyn’s hypothesis that some globular proteins may switch between two active states, rigid (N) and soft (MG), to work in solution or interact with partners.
Collapse
Affiliation(s)
- Valentina E. Bychkova
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia; (V.E.B.); (A.V.F.)
| | - Dmitry A. Dolgikh
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117871 Moscow, Russia;
| | - Vitalii A. Balobanov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia; (V.E.B.); (A.V.F.)
- Correspondence:
| | - Alexei V. Finkelstein
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia; (V.E.B.); (A.V.F.)
| |
Collapse
|
3
|
Speck D, Kleinau G, Meininghaus M, Erbe A, Einfeldt A, Szczepek M, Scheerer P, Pütter V. Expression and Characterization of Relaxin Family Peptide Receptor 1 Variants. Front Pharmacol 2022; 12:826112. [PMID: 35153771 PMCID: PMC8832513 DOI: 10.3389/fphar.2021.826112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 12/31/2021] [Indexed: 12/31/2022] Open
Abstract
G-protein coupled receptors (GPCR) transduce extracellular stimuli into the cell interior and are thus centrally involved in almost all physiological-neuronal processes. This essential function and association with many diseases or pathological conditions explain why GPCRs are one of the priority targets in medical and pharmacological research, including structure determination. Despite enormous experimental efforts over the last decade, both the expression and purification of these membrane proteins remain elusive. This is attributable to specificities of each GPCR subtype and the finding of necessary experimental in vitro conditions, such as expression in heterologous cell systems or with accessory proteins. One of these specific GPCRs is the leucine-rich repeat domain (LRRD) containing GPCR 7 (LGR7), also termed relaxin family peptide receptor 1 (RXFP1). This receptor is characterized by a large extracellular region of around 400 amino acids constituted by several domains, a rare feature among rhodopsin-like (class A) GPCRs. In the present study, we describe the expression and purification of RXFP1, including the design of various constructs suitable for functional/biophysical studies and structure determination. Based on available sequence information, homology models, and modern biochemical and genetic tools, several receptor variations with different purification tags and fusion proteins were prepared and expressed in Sf9 cells (small-scale), followed by an analytic fluorescence-detection size-exclusion chromatography (F-SEC) to evaluate the constructs. The most promising candidates were expressed and purified on a large-scale, accompanied by ligand binding studies using surface plasmon resonance spectroscopy (SPR) and by determination of signaling capacities. The results may support extended studies on RXFP1 receptor constructs serving as targets for small molecule ligand screening or structural elucidation by protein X-ray crystallography or cryo-electron microscopy.
Collapse
Affiliation(s)
- David Speck
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Berlin, Germany
| | - Gunnar Kleinau
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Berlin, Germany
| | - Mark Meininghaus
- Bayer AG, Research and Development, Pharmaceuticals, Wuppertal, Germany
| | - Antje Erbe
- Bayer AG, Research and Development, Pharmaceuticals, Berlin, Germany
- NUVISAN ICB GmbH, Berlin, Germany
| | - Alexandra Einfeldt
- Bayer AG, Research and Development, Pharmaceuticals, Berlin, Germany
- NUVISAN ICB GmbH, Berlin, Germany
| | - Michal Szczepek
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Berlin, Germany
| | - Patrick Scheerer
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography & Signal Transduction, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- *Correspondence: Patrick Scheerer, ; Vera Pütter,
| | - Vera Pütter
- Bayer AG, Research and Development, Pharmaceuticals, Berlin, Germany
- NUVISAN ICB GmbH, Berlin, Germany
- *Correspondence: Patrick Scheerer, ; Vera Pütter,
| |
Collapse
|
4
|
Chen TY, Li X, Hung CH, Bahudhanapati H, Tan J, Kass DJ, Zhang Y. The relaxin family peptide receptor 1 (RXFP1): An emerging player in human health and disease. Mol Genet Genomic Med 2020; 8:e1194. [PMID: 32100955 PMCID: PMC7196478 DOI: 10.1002/mgg3.1194] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
Background Relaxin/relaxin family peptide receptor 1 (RXFP1) signaling is important for both normal physiology and disease. Strong preclinical evidence supports relaxin as a potent antifibrotic molecule. However, relaxin‐based therapy failed in clinical trial in patients with systemic sclerosis. We and others have discovered that aberrant expression of RXFP1 may contribute to the abnormal relaxin/RXFP1 signaling in different diseases. Reduced RXFP1 expression and alternative splicing transcripts with potential functional consequences have been observed in fibrotic tissues. A relative decrease in RXFP1 expression in fibrotic tissues—specifically lung and skin—may explain a potential insensitivity to relaxin. In addition, receptor dimerization also plays important roles in relaxin/RXFP1 signaling. Methods This review describes the tissue specific expression, characteristics of the splicing variants, and homo/heterodimerization of RXFP1 in both normal physiological function and human diseases. We discuss the potential implications of these molecular features for developing therapeutics to restore relaxin/RXFP1 signaling and to harness relaxin's potential antifibrotic effects. Results Relaxin/RXFP1 signaling is important in both normal physiology and in human diseases. Reduced expression of RXFP1 in fibrotic lung and skin tissues surrenders both relaxin/RXFP1 signaling and their responsiveness to exogenous relaxin treatments. Alternative splicing and receptor dimerization are also important in regulating relaxin/RXFP1 signaling. Conclusions Understanding the molecular mechanisms that drive aberrant expression of RXFP1 in disease and the functional roles of alternative splicing and receptor dimerization will provide insight into therapeutic targets that may restore the relaxin responsiveness of fibrotic tissues.
Collapse
Affiliation(s)
- Ting-Yun Chen
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.,Institute of Allied Health Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Xiaoyun Li
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ching-Hsia Hung
- Institute of Allied Health Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Harinath Bahudhanapati
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jiangning Tan
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel J Kass
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yingze Zhang
- Division of Pulmonary, Allergy and Critical Care Medicine and the Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| |
Collapse
|
5
|
Chow BSM, Kocan M, Shen M, Wang Y, Han L, Chew JY, Wang C, Bosnyak S, Mirabito-Colafella KM, Barsha G, Wigg B, Johnstone EKM, Hossain MA, Pfleger KDG, Denton KM, Widdop RE, Summers RJ, Bathgate RAD, Hewitson TD, Samuel CS. AT1R-AT2R-RXFP1 Functional Crosstalk in Myofibroblasts: Impact on the Therapeutic Targeting of Renal and Cardiac Fibrosis. J Am Soc Nephrol 2019; 30:2191-2207. [PMID: 31511361 DOI: 10.1681/asn.2019060597] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/29/2019] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Recombinant human relaxin-2 (serelaxin), which has organ-protective actions mediated via its cognate G protein-coupled receptor relaxin family peptide receptor 1 (RXFP1), has emerged as a potential agent to treat fibrosis. Studies have shown that serelaxin requires the angiotensin II (AngII) type 2 receptor (AT2R) to ameliorate renal fibrogenesis in vitro and in vivo. Whether its antifibrotic actions are affected by modulation of the AngII type 1 receptor (AT1R), which is expressed on myofibroblasts along with RXFP1 and AT2R, is unknown. METHODS We examined the signal transduction mechanisms of serelaxin when applied to primary rat renal and human cardiac myofibroblasts in vitro, and in three models of renal- or cardiomyopathy-induced fibrosis in vivo. RESULTS The AT1R blockers irbesartan and candesartan abrogated antifibrotic signal transduction of serelaxin via RXFP1 in vitro and in vivo. Candesartan also ameliorated serelaxin's antifibrotic actions in the left ventricle of mice with cardiomyopathy, indicating that candesartan's inhibitory effects were not confined to the kidney. We also demonstrated in a transfected cell system that serelaxin did not directly bind to AT1Rs but that constitutive AT1R-RXFP1 interactions could form. To potentially explain these findings, we also demonstrated that renal and cardiac myofibroblasts expressed all three receptors and that antagonists acting at each receptor directly or allosterically blocked the antifibrotic effects of either serelaxin or an AT2R agonist (compound 21). CONCLUSIONS These findings have significant implications for the concomitant use of RXFP1 or AT2R agonists with AT1R blockers, and suggest that functional interactions between the three receptors on myofibroblasts may represent new targets for controlling fibrosis progression.
Collapse
Affiliation(s)
- Bryna S M Chow
- Florey Institute of Neuroscience and Mental Health.,Department of Biochemistry and Molecular Biology, and
| | - Martina Kocan
- Florey Institute of Neuroscience and Mental Health.,Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Matthew Shen
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Yan Wang
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Lei Han
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Jacqueline Y Chew
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Chao Wang
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Sanja Bosnyak
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Katrina M Mirabito-Colafella
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Giannie Barsha
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Belinda Wigg
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Elizabeth K M Johnstone
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia
| | | | - Kevin D G Pfleger
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Western Australia, Australia.,Department of Pharmacology and Therapeutics, ARC Centre for Personalised Therapeutic Technologies, Melbourne, Australia; and.,Dimerix Limited, Nedlands, Western Australia, Australia
| | - Kate M Denton
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Robert E Widdop
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| | - Ross A D Bathgate
- Florey Institute of Neuroscience and Mental Health.,Department of Biochemistry and Molecular Biology, and
| | - Tim D Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Chrishan S Samuel
- Department of Biochemistry and Molecular Biology, and .,Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Pharmacology and
| |
Collapse
|
6
|
Thanasupawat T, Glogowska A, Nivedita-Krishnan S, Wilson B, Klonisch T, Hombach-Klonisch S. Emerging roles for the relaxin/RXFP1 system in cancer therapy. Mol Cell Endocrinol 2019; 487:85-93. [PMID: 30763603 DOI: 10.1016/j.mce.2019.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 02/06/2023]
Abstract
A role for the hormone relaxin in cancer was described well before the receptor was identified. Relaxin predominantly increases the growth and invasive potential in cancers of different origins. However, relaxin was also shown to promote cell differentiation and to act in a dose-and time-dependent manner in different cancer cell models used. Following the discovery of the relaxin like family peptide receptor 1 (RXFP1) as the cellular receptor for RLN1 and RLN2, research has focussed on the ligand interaction with the large extracellular domain of RXFP1 and resulting molecular signaling mechanisms. RXFP1 activation mediates anti-apoptotic functions, angiogenesis and chemoresistance in cancer cells. This minireview summarizes the known biological functions of RXFP1 activation in different cancer entities in-vitro and in-vivo and outlines possible mechanisms to therapeutically address the relaxin-RXFP1 system in cancer cells.
Collapse
Affiliation(s)
- Thatchawan Thanasupawat
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Aleksandra Glogowska
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Sai Nivedita-Krishnan
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Brian Wilson
- Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada
| | - Thomas Klonisch
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada
| | - Sabine Hombach-Klonisch
- Department of Human Anatomy and Cell Science, College of Medicine, University of Manitoba, Winnipeg, Canada.
| |
Collapse
|
7
|
Abstract
More than 800 different human membrane-spanning G-protein-coupled receptors (GPCRs) serve as signal transducers at biological barriers. These receptors are activated by a wide variety of ligands such as peptides, ions and hormones, and are able to activate a diverse set of intracellular signaling pathways. GPCRs are of central importance in endocrine regulation, which underpins the significance of comprehensively studying these receptors and interrelated systems. During the last decade, the capacity for multimerization of GPCRs was found to be a common and functionally relevant property. The interaction between GPCR monomers results in higher order complexes such as homomers (identical receptor subtype) or heteromers (different receptor subtypes), which may be present in a specific and dynamic monomer/oligomer equilibrium. It is widely accepted that the oligomerization of GPCRs is a mechanism for determining the fine-tuning and expansion of cellular processes by modification of ligand action, expression levels, and related signaling outcome. Accordingly, oligomerization provides exciting opportunities to optimize pharmacological treatment with respect to receptor target and tissue selectivity or for the development of diagnostic tools. On the other hand, GPCR heteromerization may be a potential reason for the undesired side effects of pharmacological interventions, faced with numerous and common mutual signaling modifications in heteromeric constellations. Finally, detailed deciphering of the physiological occurrence and relevance of specific GPCR/GPCR-ligand interactions poses a future challenge. This review will tackle the aspects of GPCR oligomerization with specific emphasis on family A GPCRs involved in endocrine regulation, whereby only a subset of these receptors will be discussed in detail.
Collapse
Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Anne Müller
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| |
Collapse
|
8
|
Xu JG, Huang C, Yang Z, Jin M, Fu P, Zhang N, Luo J, Li D, Liu M, Zhou Y, Zhu Y. Crystal structure of LGR4-Rspo1 complex: insights into the divergent mechanisms of ligand recognition by leucine-rich repeat G-protein-coupled receptors (LGRs). J Biol Chem 2014; 290:2455-65. [PMID: 25480784 DOI: 10.1074/jbc.m114.599134] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Leucine-rich repeat G-protein-coupled receptors (LGRs) are a unique class of G-protein-coupled receptors characterized by a large extracellular domain to recognize ligands and regulate many important developmental processes. Among the three groups of LGRs, group B members (LGR4-6) recognize R-spondin family proteins (Rspo1-4) to stimulate Wnt signaling. In this study, we successfully utilized the "hybrid leucine-rich repeat technique," which fused LGR4 with the hagfish VLR protein, to obtain two recombinant human LGR4 proteins, LGR415 and LGR49. We determined the crystal structures of ligand-free LGR415 and the LGR49-Rspo1 complex. LGR4 exhibits a twisted horseshoe-like structure. Rspo1 adopts a flat and β-fold architecture and is bound in the concave surface of LGR4 in the complex through electrostatic and hydrophobic interactions. All the Rspo1-binding residues are conserved in LGR4-6, suggesting that LGR4-6 bind R-spondins through an identical surface. Structural analysis of our LGR4-Rspo1 complex with the previously determined LGR4 and LGR5 structures revealed that the concave surface of LGR4 is the sole binding site for R-spondins, suggesting a one-site binding model of LGR4-6 in ligand recognition. The molecular mechanism of LGR4-6 is distinct from the two-step mechanism of group A receptors LGR1-3 and the multiple-interface binding model of group C receptors LGR7-8, suggesting LGRs utilize the divergent mechanisms for ligand recognition. Our structures, together with previous reports, provide a comprehensive understanding of the ligand recognition by LGRs.
Collapse
Affiliation(s)
- Jin-Gen Xu
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Chunfeng Huang
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Zhengfeng Yang
- the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Mengmeng Jin
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Panhan Fu
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Ni Zhang
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Jian Luo
- the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Dali Li
- the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Mingyao Liu
- the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yan Zhou
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| | - Yongqun Zhu
- From the Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang 310058 and
| |
Collapse
|
9
|
Abstract
The TSH receptor (TSHR) is a member of the glycoprotein hormone receptors, a subfamily of family A G protein-coupled receptors. The TSHR is of great importance for the growth and function of the thyroid gland. The TSHR and its endogenous ligand TSH are pivotal proteins with respect to a variety of physiological functions and malfunctions. The molecular events of TSHR regulation can be summarized as a process of signal transduction, including signal reception, conversion, and amplification. The steps during signal transduction from the extra- to the intracellular sites of the cell are not yet comprehensively understood. However, essential new insights have been achieved in recent years on the interrelated mechanisms at the extracellular region, the transmembrane domain, and intracellular components. This review contains a critical summary of available knowledge of the molecular mechanisms of signal transduction at the TSHR, for example, the key amino acids involved in hormone binding or in the structural conformational changes that lead to G protein activation or signaling regulation. Aspects of TSHR oligomerization, signaling promiscuity, signaling selectivity, phenotypes of genetic variations, and potential extrathyroidal receptor activity are also considered, because these are relevant to an understanding of the overall function of the TSHR, including physiological, pathophysiological, and pharmacological perspectives. Directions for future research are discussed.
Collapse
Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, Ostring 3, Augustenburger Platz 1, 13353 Berlin, Germany.
| | | | | | | | | |
Collapse
|
10
|
Bruell S, Kong RCK, Petrie EJ, Hoare B, Wade JD, Scott DJ, Gooley PR, Bathgate RAD. Chimeric RXFP1 and RXFP2 Receptors Highlight the Similar Mechanism of Activation Utilizing Their N-Terminal Low-Density Lipoprotein Class A Modules. Front Endocrinol (Lausanne) 2013; 4:171. [PMID: 24273532 PMCID: PMC3822782 DOI: 10.3389/fendo.2013.00171] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 10/25/2013] [Indexed: 11/13/2022] Open
Abstract
Relaxin family peptide (RXFP) receptors 1 and 2 are unique G-protein coupled receptors in that they contain an N-terminal low-density lipoprotein type A (LDLa) module which is necessary for receptor activation. The current hypothesis suggests that upon ligand binding the LDLa module interacts with the transmembrane (TM) domain of a homodimer partner receptor to induce the active receptor conformations. We recently demonstrated that three residues in the N-terminus of the RXFP1 LDLa module are potentially involved in hydrophobic interactions with the receptor to drive activation. RXFP2 shares two out of three of the residues implicated, suggesting that the two LDLa modules could be interchanged without adversely affecting activity. However, in 2007 it was shown that a chimera consisting of the RXFP1 receptor with its LDLa swapped for that of RXFP2 did not signal. We noticed this construct also contained the RXFP2 region linking the LDLa to the leucine-rich repeats. We therefore constructed chimeric RXFP1 and RXFP2 receptors with their LDLa modules swapped immediately C-terminally to the final cysteine residue of the module, retaining the native linker. In addition, we exchanged the TM domains of the chimeras to explore if matching the LDLa module with the TM domain of its native receptor altered activity. All of the chimeras were expressed at the surface of HEK293T cells with ligand binding profiles similar to the wild-type receptors. Importantly, as predicted, ligand binding was able to induce cAMP-based signaling. Chimeras of RXFP1 with the LDLa of RXFP2 demonstrated reduced H2 relaxin potency with the pairing of the RXFP2 TM with the RXFP2 LDLa necessary for full ligand efficacy. In contrast the ligand-mediated potencies and efficacies on the RXFP2 chimeras were similar suggesting the RXFP1 LDLa module has similar efficacy on the RXFP2 TM domain. Our studies demonstrate the LDLa modules of RXFP1 and RXFP2 modulate receptor activation via a similar mechanism.
Collapse
Affiliation(s)
- Shoni Bruell
- Florey Department of Neuroscience and Mental Health, Florey Institute of Neuroscience and Mental Health , Melbourne, VIC , Australia ; Department of Biochemistry and Molecular Biology , Melbourne, VIC , Australia
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Hossain MA, Chow Suet Man B, Zhao C, Xu Q, Du XJ, Wade JD, Samuel CS. H3 Relaxin Demonstrates Antifibrotic Properties via the RXFP1 Receptor. Biochemistry 2011; 50:1368-75. [DOI: 10.1021/bi1013968] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | | | | | - Qi Xu
- Baker IDI Heart and Diabetes Institute, St. Kilda Road Central, Melbourne, Victoria 8008, Australia
| | - Xiao-Jun Du
- Baker IDI Heart and Diabetes Institute, St. Kilda Road Central, Melbourne, Victoria 8008, Australia
| | | | | |
Collapse
|
12
|
Hombach-Klonisch S, Bialek J, Radestock Y, Truong A, Agoulnik AI, Fiebig B, Willing C, Weber E, Hoang-Vu C, Klonisch T. INSL3 has tumor-promoting activity in thyroid cancer. Int J Cancer 2010; 127:521-31. [PMID: 19950223 DOI: 10.1002/ijc.25068] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The functional role of INSL3 and its receptor RXFP2 in carcinogenesis is largely unknown. We have previously demonstrated (pro-)cathepsin-L as a target of INSL3 in human thyroid cancer cells facilitating penetration of tumor cells through elastin matrices. We demonstrate the expression of RXFP2 in human thyroid tissues and in mouse follicular thyroid epithelial cells using Cre-recombinase transgene driven by Rxfp2 promoter. Recombinant and secreted INSL3 increased the motility of thyroid carcinoma (TC) cells in an autocrine/paracrine manner. This effect required the presence of RXFP2. We identified S100A4 as a novel INSL3 target molecule and showed that S100A4 facilitated INSL3-induced enhanced motility. Stable transfectants of the human follicular TC cell line FTC-133 expressing and secreting bioactive human INSL3 displayed enhanced anchorage-independent growth in soft agar assays. Xenotransplant experiments in nude mice showed that INSL3, but not EGFP-mock transfectants, developed fast-growing and highly vascularized xenografts. We used human umbilical vein endothelial cells in capillary tube formation assays to demonstrate increased 2-dimensional tube formations induced by recombinant human INSL3 and human S100A4 comparable to the effect of vascular endothelial growth factor used as positive control. We conclude that INSL3 is a powerful and multifunctional promoter of tumor growth and angiogenesis in human thyroid cancer cell xenografts. INSL3 actions involve RXFP2 activation and the secretion of S100A4 and (pro-)cathepsin-L.
Collapse
|
13
|
|