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Chikh A, Raimondi C. Endothelial Neuropilin-1: a multifaced signal transducer with an emerging role in inflammation and atherosclerosis beyond angiogenesis. Biochem Soc Trans 2024; 52:137-150. [PMID: 38323651 PMCID: PMC10903451 DOI: 10.1042/bst20230329] [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: 10/24/2023] [Revised: 01/08/2024] [Accepted: 01/12/2024] [Indexed: 02/08/2024]
Abstract
Neuropilin-1 (NRP1) is a transmembrane glycoprotein expressed by several cell types including, neurons, endothelial cells (ECs), smooth muscle cells, cardiomyocytes and immune cells comprising macrophages, dendritic cells and T cell subsets. Since NRP1 discovery in 1987 as an adhesion molecule in the frog nervous system, more than 2300 publications on PubMed investigated the function of NRP1 in physiological and pathological contexts. NRP1 has been characterised as a coreceptor for class 3 semaphorins and several members of the vascular endothelial growth factor (VEGF) family. Because the VEGF family is the main regulator of blood and lymphatic vessel growth in addition to promoting neurogenesis, neuronal patterning, neuroprotection and glial growth, the role of NRP1 in these biological processes has been extensively investigated. It is now established that NRP1 promotes the physiological growth of new vessels from pre-existing ones in the process of angiogenesis. Furthermore, several studies have shown that NRP1 mediates signalling pathways regulating pathological vascular growth in ocular neovascular diseases and tumour development. Less defined are the roles of NRP1 in maintaining the function of the quiescent established vasculature in an adult organism. This review will focus on the opposite roles of NRP1 in regulating transforming growth factor β signalling pathways in different cell types, and on the emerging role of endothelial NRP1 as an atheroprotective, anti-inflammatory factor involved in the response of ECs to shear stress.
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Affiliation(s)
- Anissa Chikh
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, U.K
| | - Claudio Raimondi
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Centre of Cardiovascular Medicine and Devices, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, U.K
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2
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Zou LL, Li JR, Li H, Tan JL, Wang MX, Liu NN, Gao RM, Yan HY, Wang XK, Dong B, Li YH, Peng ZG. TGF-β isoforms inhibit hepatitis C virus propagation in transforming growth factor beta/SMAD protein signalling pathway dependent and independent manners. J Cell Mol Med 2021; 25:3498-3510. [PMID: 33682288 PMCID: PMC8034461 DOI: 10.1111/jcmm.16432] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 02/12/2021] [Accepted: 02/20/2021] [Indexed: 02/06/2023] Open
Abstract
Transforming growth factor beta (TGF‐β) plays an important role in the viral liver disease progression via controlling viral propagation and mediating inflammation‐associated responses. However, the antiviral activities and mechanisms of TGF‐β isoforms, including TGF‐β1, TGF‐β2 and TGF‐β3, remain unclear. Here, we demonstrated that all of the three TGF‐β isoforms were increased in Huh7.5 cells infected by hepatitis C virus (HCV), but in turn, the elevated TGF‐β isoforms could inhibit HCV propagation with different potency in infectious HCV cell culture system. TGF‐β isoforms suppressed HCV propagation through interrupting several different stages in the whole HCV life cycle, including virus entry and intracellular replication, in TGF‐β/SMAD signalling pathway–dependent and TGF‐β/SMAD signalling pathway–independent manners. TGF‐β isoforms showed additional anti‐HCV activities when combined with each other. However, the elevated TGF‐β1 and TGF‐β2, not TGF‐β3, could also induce liver fibrosis with a high expression of type I collagen alpha‐1 and α‐smooth muscle actin in LX‐2 cells. Our results showed a new insight into TGF‐β isoforms in the HCV‐related liver disease progression.
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Affiliation(s)
- Li-Li Zou
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jian-Rui Li
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Key Laboratory of Biotechnology of Antibiotics, The National Health and Family Planning Commission (NHFPC), Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hu Li
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Key Laboratory of Biotechnology of Antibiotics, The National Health and Family Planning Commission (NHFPC), Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jia-Li Tan
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Mei-Xi Wang
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Nan-Nan Liu
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Rong-Mei Gao
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hai-Yan Yan
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Key Laboratory of Biotechnology of Antibiotics, The National Health and Family Planning Commission (NHFPC), Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xue-Kai Wang
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Biao Dong
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu-Huan Li
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Key Laboratory of Biotechnology of Antibiotics, The National Health and Family Planning Commission (NHFPC), Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zong-Gen Peng
- CAMS Key Laboratory of Antiviral Drug Research, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Key Laboratory of Biotechnology of Antibiotics, The National Health and Family Planning Commission (NHFPC), Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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3
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4
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De Crescenzo G, Hinck CS, Shu Z, Zúñiga J, Yang J, Tang Y, Baardsnes J, Mendoza V, Sun L, López-Casillas F, O'Connor-McCourt M, Hinck AP. Three key residues underlie the differential affinity of the TGFbeta isoforms for the TGFbeta type II receptor. J Mol Biol 2005; 355:47-62. [PMID: 16300789 DOI: 10.1016/j.jmb.2005.10.022] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2005] [Revised: 08/16/2005] [Accepted: 10/06/2005] [Indexed: 10/25/2022]
Abstract
TGFbeta1, beta2, and beta3 are 25kDa homodimeric polypeptides that play crucial non-overlapping roles in development, tumor suppression, and wound healing. They exhibit 70-82% sequence identity and transduce their signals by binding and bringing together the TGFbeta type I and type II receptors, TbetaRI and TbetaRII. TGFbeta2 differs from the other isoforms in that it binds TbetaRII weakly and is dependent upon the co-receptor betaglycan for function. To explore the physicochemical basis underlying these differences, we generated a series of single amino acid TbetaRII variants based on the crystal structure of the TbetaRII:TGFbeta3 complex and examined these in terms of their TGFbeta isoform binding affinity and their equilibrium stability. The results showed that TbetaRII Ile53 and Glu119, which contact TGFbeta3 Val92 and Arg25, respectively, together with TbetaRII Asp32, Glu55, and Glu75, which contact TGFbeta3 Arg94, each contribute significantly, between 1 kcal mol(-1) to 1.5 kcal mol(-1), to ligand binding affinities. These contacts likely underlie the estimated 4.1 kcal mol(-1) lower affinity with which TbetaRII binds TGFbeta2 as these three ligand residues are unchanged in TGFbeta1 but are conservatively substituted in TGFbeta2 (Lys25, Ile92, and Lys94). To test this hypothesis, a TGFbeta2 variant was generated in which these three residues were changed to those in TGFbetas 1 and 3. This variant exhibited receptor binding affinities comparable to those of TGFbetas 1 and 3. Together, these results show that these three residues underlie the lowered affinity of TGFbeta2 for TbetaRII and that all isoforms likely induce assembly of the TGFbeta signaling receptors in the same overall manner.
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Affiliation(s)
- Gregory De Crescenzo
- Biotechnology Research Institute, National Research Council, Montreal, Que. Canada H4P2R2
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5
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Young GD, Murphy-Ullrich JE. Molecular interactions that confer latency to transforming growth factor-beta. J Biol Chem 2004; 279:38032-9. [PMID: 15208302 DOI: 10.1074/jbc.m405658200] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A major point of regulation of transforming growth factor-beta (TGF-beta) function is through control of activation of the latent TGF-beta complex, which consists of the latency associated peptide (LAP) secreted in non-covalent association with mature TGF-beta. Activation involves proteolysis, dissociation, or altered binding of LAP. However, the mechanism by which LAP confers latency to TGF-beta is poorly understood. Previously, we identified a conserved sequence near the N terminus of LAP as a site of thrombospondin-1 (TSP1) binding to the latent complex. Now we show that expression of the TGF-beta1-latent complex deleted in the TSP1 binding site ((54)LSKL) of LAP (DeltaLSKL LAP) results in secretion of LAP, but not of mature TGF-beta. DeltaLSKL LAP also fails to bind soluble or immobilized TGF-beta1. Consistent with an inability to bind the mature domain, DeltaLSKL LAP is unable to confer latency to TGF-beta, suggesting that the LSKL sequence is important, not only for TSP1 binding and activation, but also for binding to the mature domain. We identified the sequence (94)RKPK in the receptor-binding region of mature TGF-beta1 as the binding site for LAP. Peptides of the RKPK sequence bind LAP and inhibit LAP/TGF-beta association. RKPK peptides also activate latent TGF-beta, presumably by disrupting LAP-mature TGF-beta interactions. These studies provide a molecular basis for both latency and activation by TSP1 through the LSKL sequence of LAP binding to the RKPK sequence of mature TGF-beta.
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Affiliation(s)
- Geoffrey D Young
- Medical Scientist Training Program, Cell Adhesion and Matrix Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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6
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Flanders KC, Burmester JK. Medical applications of transforming growth factor-beta. Clin Med Res 2003; 1:13-20. [PMID: 15931280 PMCID: PMC1069016 DOI: 10.3121/cmr.1.1.13] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2002] [Accepted: 08/26/2002] [Indexed: 01/18/2023]
Abstract
Transforming growth factor-beta (TGF-beta) proteins and their antagonists have entered clinical trials. These multi-functional regulators of cell growth and differentiation induce extracellular matrix proteins and suppress the immune system making TGF-betas useful in treatment of wounds with impaired healing, mucositis, fractures, ischemia-reperfusion injuries, and autoimmune disease. In diseases such as keloids, glomerulonephritis and pulmonary fibrosis, excessive expression of TGF-beta has been implicated as being responsible for accumulation of detrimental scar tissue. In these conditions, agents that block TGF-beta have prevented or reversed disease. Similarly, in carcinogenesis, blocking TGF-beta activity may be valuable in stimulating an immune response towards metastasis. As these blocking agents receive approval, we will likely have new therapies for previously recalcitrant diseases.
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Affiliation(s)
- Kathleen C Flanders
- Laboratory of Cell Regulation and Carcinogenesis, National Institutes of Health, Bethesda, Maryland, USA
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7
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Bocharov EV, Korzhnev DM, Blommers MJJ, Arvinte T, Orekhov VY, Billeter M, Arseniev AS. Dynamics-modulated biological activity of transforming growth factor beta3. J Biol Chem 2002; 277:46273-9. [PMID: 12221089 DOI: 10.1074/jbc.m206274200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor beta3 (TGF-beta3) is an important mediator of growth, maintenance, and repair processes in human cells. Internal dynamic properties have been derived from (15)N NMR relaxation data and mapped onto the spatial structure of TGF-beta3. The pattern of internal dynamics in the structure identifies potential "hot spots" of binding free energy and reveals the importance of conformational entropy in the interaction of TGF-beta3 with the receptors. The observed internal dynamics set TGF-beta3 apart from other TGF-beta isoforms, with which it shares the same fold. These findings may explain functional differences among the various TGF-beta isoforms and thus prove essential in the search for related therapeutic agents.
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Affiliation(s)
- Eduard V Bocharov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia
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8
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Michon IN, Penning LC, Molenaar TJM, van Berkel TJC, Biessen EAL, Kuiper J. The effect of TGF-beta receptor binding peptides on smooth muscle cells. Biochem Biophys Res Commun 2002; 293:1279-86. [PMID: 12054515 DOI: 10.1016/s0006-291x(02)00378-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
TGF-beta1 is a potent regulator of vascular smooth muscle cell (VSMC) proliferation, migration, and extracellular matrix (ECM) synthesis. In this study, we selected two peptides, IM-1 and IM-2, that bind to the TGF-beta type II receptor (TGF-beta RII) using phage display. IM-1 and IM-2 bind to the TGF-beta RII, with a K(d) of 1 microM. Like TGF-beta, IM-1 induced VSMC chemotaxis and PAI-1 mRNA expression, as determined using Boyden chambers and real time quantitative PCR. In contrast, IM-2 had no effect on VSMC chemotaxis or PAI-1 induction. Induction of ECM synthesis, involving proteins such as osteopontin and alpha-smooth muscle actin, was determined by ELISA. Osteopontin expression was inhibited by both peptides, but TGF-beta-induced alpha-smooth muscle actin expression could only be inhibited by IM-1. In conclusion, IM-1 activity on VSMC is agonistic with TGF-beta, except for ECM synthesis, whereas the IM-2 peptide is antagonistic for some examined TGF-beta functions.
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Affiliation(s)
- Ingrid N Michon
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
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9
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Guimond A, Sulea T, Pen A, Ear P, O'Connor-McCourt MD. Site-directed mutagenesis of the type II TGF-beta receptor indicates a ligand-binding site distinct from that of the type II activin receptor. FEBS Lett 2002; 515:13-9. [PMID: 11943186 DOI: 10.1016/s0014-5793(02)02378-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Site-directed mutagenesis was used to map the ligand-binding surface of the type II transforming growth factor-beta receptor extracellular domain (TbetaRII-ECD). Two putative ligand-binding sites were probed, the first being a predicted hydrophobic patch, the second being the finger 1 surface loop. Nine residues were mutated in the context of full-length TbetaRII and the effect of these mutations on ligand-binding and receptor signaling was analyzed. Complementary information was obtained by examining 'natural' evolutionary TbetaRII mutations. Together, the results indicate that residues within the finger 1 region, but not the hydrophobic patch, of the TbetaRII-ECD are required for productive ligand-binding. We conclude that, surprisingly, the ECDs of TbetaRII and type II activin receptor utilize distinct interacting surfaces for binding their respective ligands.
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MESH Headings
- Activin Receptors, Type II/chemistry
- Activin Receptors, Type II/genetics
- Activin Receptors, Type II/metabolism
- Binding Sites/physiology
- Cell Line
- DNA-Binding Proteins/metabolism
- Gene Expression
- Humans
- Kidney/cytology
- Kidney/metabolism
- Ligands
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Phosphorylation
- Protein Binding/physiology
- Protein Serine-Threonine Kinases
- Protein Structure, Tertiary/physiology
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Transforming Growth Factor beta/chemistry
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Sequence Homology, Amino Acid
- Signal Transduction/physiology
- Smad2 Protein
- Trans-Activators/metabolism
- Transfection
- Transforming Growth Factor beta/metabolism
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Affiliation(s)
- Alain Guimond
- Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, H4P 2R2, Montréal, QC, Canada
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10
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Guimond A, Sulea T, Zwaagstra JC, Ekiel I, O'Connor-McCourt MD. Identification of a functional site on the type I TGF-beta receptor by mutational analysis of its ectodomain. FEBS Lett 2002; 513:147-52. [PMID: 11904140 DOI: 10.1016/s0014-5793(01)03231-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Six charged amino acid residues located in the ectodomain of the full-length type I transforming growth factor (TGF)-beta receptor were individually mutated to alanine. Mutation of residues D47, D98, K102 and E104 resulted in functionally impaired receptors as demonstrated by a marked decrease in ligand-dependent signaling and ligand internalization relative to the wild-type receptor. The other two mutants (K39A and K87A) exhibited wild-type-like activity. Molecular modeling indicates that the four functionally important residues are located on the convex face of the ectodomain structure. Since mutation of these four residues affects signaling and ligand internalization but not ligand binding, we propose that this functional site is an interacting site between type I and II receptors.
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MESH Headings
- Activin Receptors, Type I/chemistry
- Activin Receptors, Type I/genetics
- Activin Receptors, Type I/metabolism
- Amino Acid Sequence
- Animals
- Cells, Cultured
- DNA Mutational Analysis
- Humans
- Ligands
- Models, Molecular
- Molecular Sequence Data
- Protein Serine-Threonine Kinases
- Protein Structure, Tertiary
- Rats
- Receptor, Transforming Growth Factor-beta Type I
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Transforming Growth Factor beta/chemistry
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Sequence Homology, Amino Acid
- Signal Transduction
- Structure-Activity Relationship
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Affiliation(s)
- Alain Guimond
- Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, H4P 2R2, Montréal, QC, Canada
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11
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Docagne F, Colloc'h N, Bougueret V, Page M, Paput J, Tripier M, Dutartre P, MacKenzie ET, Buisson A, Komesli S, Vivien D. A soluble transforming growth factor-beta (TGF-beta ) type I receptor mimics TGF-beta responses. J Biol Chem 2001; 276:46243-50. [PMID: 11544249 DOI: 10.1074/jbc.m010915200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) signaling requires a ligand-dependent interaction of TGF-beta receptors Tau beta R-I and Tau beta R-II. It has been previously demonstrated that a soluble TGF-beta type II receptor could be used as a TGF-beta antagonist. Here we have generated and investigated the biochemical and signaling properties of a soluble TGF-beta type I receptor (Tau beta RIs-Fc). As reported for the wild-type receptor, the soluble Tau beta R-I does not bind TGF-beta 1 on its own. Surprisingly, in the absence of TGF-beta1, the Tau beta RIs-Fc mimicked TGF-beta 1-induced transcriptional and growth responses in mink lung epithelial cells (Mv1Lu). Signaling induced by the soluble TGF-beta type I receptor is mediated via the obligatory presence of both TGF-beta type I and type II receptors at the cell surface since no signal was observed in Mv1Lu-derivated mutants for TGF-beta receptors R-1B and DR-26. The comparison between the structures of TGF-betas and a three-dimensional model of the extracellular domain of Tau beta RI has shown that five residues of the supposed binding site of TGF-beta 1 (Lys(31), His(34), Glu(5), Tyr(91), and Lys(94)) were found with equivalent biochemical properties and similar spatial positions.
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Affiliation(s)
- F Docagne
- Université de Caen, UMR CNRS 6551, Centre Cyceron, IFR 47, Bd H. Becquerel, BP 5229, 14074 Caen Cedex, France
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12
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Fairlie WD, Zhang HP, Wu WM, Pankhurst SL, Bauskin AR, Russell PK, Brown PK, Breit SN. The propeptide of the transforming growth factor-beta superfamily member, macrophage inhibitory cytokine-1 (MIC-1), is a multifunctional domain that can facilitate protein folding and secretion. J Biol Chem 2001; 276:16911-8. [PMID: 11278594 DOI: 10.1074/jbc.m010000200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Macrophage inhibitory cytokine-1 (MIC-1) is a divergent member of the transforming growth factor-beta (TGF-beta) superfamily. While it is synthesized in a pre-pro form, it is unique among superfamily members because it does not require its propeptide for correct folding or secretion of the mature peptide. To investigate factors that enable these propeptide independent events to occur, we constructed MIC-1/TGF-beta1 chimeras, both with and without a propeptide. All chimeras without a propeptide secreted less efficiently compared with the corresponding constructs with propeptide. Folding and secretion were most affected after replacement of the predicted major alpha-helix in the mature protein, residues 56-68. Exchanging the human propeptide in this chimera with either the murine MIC-1 or TGF-beta1 propeptide resulted in secretion of the unprocessed, monomeric chimera, suggesting a specific interaction between the human MIC-1 propeptide and mature peptide. Propeptide deletion mutants enabled identification of a region between residues 56 and 78, which is important for the interaction between the propeptide and the mature peptide. Cotransfection experiments demonstrated that the propeptide must be in cis with the mature peptide for this phenomenon to occur. These results suggest a model for TGF-beta superfamily protein folding.
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Affiliation(s)
- W D Fairlie
- Centre for Immunology, Saint Vincent's Hospital and University of New South Wales, Victoria Street, Sydney, New South Wales 2010, Australia
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14
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Ezal CH, Marion CD, Smith WC. Primary structure requirements for Xenopus nodal-related 3 and a comparison with regions required by Xenopus nodal-related 2. J Biol Chem 2000; 275:14124-31. [PMID: 10799488 DOI: 10.1074/jbc.275.19.14124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor-beta superfamily members play important roles in the early development of animals. Activin and the Xenopus nodal related proteins 1, 2, and 4 induce muscle actin from Xenopus ectodermal explants, whereas the bone morphogenetic proteins 4 and 7 induce ectoderm to differentiate as epidermis. Bone morphogenetic proteins are antagonized by soluble binding proteins such as noggin and chordin, which leads to expression of neural cell adhesion molecule in animal caps. The transforming growth factor-beta superfamily member Xenopus nodal-related 3 also induces the neural cell adhesion molecule through inhibition of bone morphogenetic proteins. Therefore, whereas Xenopus nodal-related 2 and 3 share a high amount of sequence homology, they lead to very different cell fates. This study investigates the functional domains that distinguish the activities of these two factors. It was found that mutually exclusive regions of nodal-related 2 and 3 were required for activity. The central region of the mature domain is required for nodal-related 2 to induce muscle actin, whereas the N- and C-terminal ends of the mature domain are required for nodal-related 3 to induce neural cell adhesion molecule. These results help to define the minimal domains required for the unique activities of these factors.
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Affiliation(s)
- C H Ezal
- Department of Molecular, Cellular, and Developmental Biology, and the Neuroscience Research Institute, University of California, Santa Barbara, California 93106, USA
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15
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Baloh RH, Tansey MG, Johnson EM, Milbrandt J. Functional mapping of receptor specificity domains of glial cell line-derived neurotrophic factor (GDNF) family ligands and production of GFRalpha1 RET-specific agonists. J Biol Chem 2000; 275:3412-20. [PMID: 10652334 DOI: 10.1074/jbc.275.5.3412] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) (GDNF, neurturin, artemin, and persephin) are critical regulators of neurodevelopment and support the survival of midbrain dopaminergic and spinal motor neurons in vitro and in animal disease models making them attractive therapeutic candidates for treatment of neurodegenerative diseases. The GFLs signal through a multicomponent receptor complex comprised of a high affinity binding component (GDNF-family receptor alpha-component (GFRalpha1-GFRalpha4)) and the receptor tyrosine kinase RET. To begin characterization of GFL receptor specificity at the molecular level, we performed comprehensive homologue-scanning mutagenesis of GDNF, the prototypical member of the GFLs. Replacing short segments of GDNF with the homologous segments from persephin (PSPN) (which cannot bind or activate GFRalpha1.RET or GFRalpha2.RET) identified sites along the second finger of GDNF critical for activating the GFRalpha1.RET and GFRalpha2.RET receptor complexes. Furthermore, introduction of these regions from GDNF, neurturin, or artemin into PSPN demonstrated that they are sufficient for activating GFRalpha1. RET, but additional determinants are required for interaction with the other GFRalphas. This difference in the molecular basis of GFL-GFRalpha specificity allowed the production of GFRalpha1. RET-specific agonists and provides a foundation for understanding of GFL-GFRalpha.RET signaling at the molecular level.
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Affiliation(s)
- R H Baloh
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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16
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Huang SS, Zhou M, Johnson FE, Shieh HS, Huang JS. An active site of transforming growth factor-beta(1) for growth inhibition and stimulation. J Biol Chem 1999; 274:27754-8. [PMID: 10488119 DOI: 10.1074/jbc.274.39.27754] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) is a bifunctional growth regulator. It inhibits growth of many cell types, including epithelial cells, but stimulates growth of others (e.g. fibroblasts). The active site on the TGF-beta molecule, which mediates its growth regulatory activity, has not been defined. Here, we show that antibody to a TGF-beta(1) peptide containing the motif WSLD (52nd to 55th amino acid residues) completely blocked both (125)I-TGF-beta(1) binding to TGF-beta receptors and TGF-beta(1)-induced growth inhibition in mink lung epithelial cells. Site-directed mutagenesis analysis revealed that the replacement of Trp(52) and Asp(55) by alanine residues diminished the growth inhibitory activity of TGF-beta(1) by approximately 90%. Finally, while wild-type TGF-beta(1) was able to stimulate growth of transfected NIH 3T3 cells, the double mutant TGF-beta(1) W52A/D55A was much less active. These results support the hypothesis that the WSLD motif is an active site of TGF-beta(1), which is important for growth inhibition of epithelial cells and growth stimulation of fibroblasts.
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Affiliation(s)
- S S Huang
- Departments of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, Missouri 63104, USA.
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Qian SW, Dumont N, O'Connor-McCourt MD, Burmester JK. Distinct functional domains of TGF-beta bind receptors on endothelial cells. Growth Factors 1999; 17:63-73. [PMID: 10495963 DOI: 10.3109/08977199909001063] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Transforming growth factor-beta (TGF-beta) is a multi-functional regulator of cell growth and differentiation. Three distinct isoforms of TGF-beta exist having similar, but not identical actions. TGF-beta 1, but not TGF-beta 2, binds to T beta RII and also to endoglin, a cell surface protein abundant on endothelial cells. In contrast, the affinity constant of TGF-beta 2 for alpha 2-macroglobulin is 10-fold greater than that of TGF-beta 1. TGF-beta 2 also binds better than TGF-beta 1 to a glycosyl phosphatidylinositol (GPI)-linked binding protein expressed on vascular endothelial cells. Using chimeric TGF-beta molecules, in which selected regions of TGF-beta 1 have been exchanged for the corresponding region of TGF-beta 2, we demonstrate here that amino acids 92-95 or 94-98 of TGF-beta determine isoform specific binding to endoglin. In contrast, exchange of only amino acids 95 and 98 did not alter TGF-beta specificity. Isoform specific binding to a GPI-linked protein on EJG endothelial cells was modulated by a region containing amino acids 40-68, although exchange of only amino acids 40-47 did not confer isoform specific binding. Significantly, the 92-98 region also modulates binding of TGF-beta to the type II receptor whereas isoform specific binding to alpha 2-macroglobulin requires concerted exchange of amino acids 45 and 47. Taken together, these results show that at least three different functional domains are important modulators of TGF-beta interaction with binding proteins and receptors.
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Affiliation(s)
- S W Qian
- Edge BioSystems, Inc., Gaithersburg, MD 20879, USA
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