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Jacob R, Gorek LS. Intracellular galectin interactions in health and disease. Semin Immunopathol 2024; 46:4. [PMID: 38990375 PMCID: PMC11239732 DOI: 10.1007/s00281-024-01010-z] [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: 12/04/2023] [Accepted: 03/07/2024] [Indexed: 07/12/2024]
Abstract
In the galectin family, a group of lectins is united by their evolutionarily conserved carbohydrate recognition domains. These polypeptides play a role in various cellular processes and are implicated in disease mechanisms such as cancer, fibrosis, infection, and inflammation. Following synthesis in the cytosol, manifold interactions of galectins have been described both extracellularly and intracellularly. Extracellular galectins frequently engage with glycoproteins or glycolipids in a carbohydrate-dependent manner. Intracellularly, galectins bind to non-glycosylated proteins situated in distinct cellular compartments, each with multiple cellular functions. This diversity complicates attempts to form a comprehensive understanding of the role of galectin molecules within the cell. This review enumerates intracellular galectin interaction partners and outlines their involvement in cellular processes. The intricate connections between galectin functions and pathomechanisms are illustrated through discussions of intracellular galectin assemblies in immune and cancer cells. This underscores the imperative need to fully comprehend the interplay of galectins with the cellular machinery and to devise therapeutic strategies aimed at counteracting the establishment of galectin-based disease mechanisms.
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Affiliation(s)
- Ralf Jacob
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Karl-von-Frisch-Str. 14, D-35043, Marburg, Germany.
| | - Lena-Sophie Gorek
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Karl-von-Frisch-Str. 14, D-35043, Marburg, Germany
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2
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Peltan EL, Riley NM, Flynn RA, Roberts DS, Bertozzi CR. Galectin-3 does not interact with RNA directly. Glycobiology 2024; 34:cwad076. [PMID: 37815932 DOI: 10.1093/glycob/cwad076] [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: 04/28/2023] [Revised: 09/08/2023] [Accepted: 09/09/2023] [Indexed: 10/12/2023] Open
Abstract
Galectin-3, well characterized as a glycan binding protein, has been identified as a putative RNA binding protein, possibly through participation in pre-mRNA maturation through interactions with splicosomes. Given recent developments with cell surface RNA biology, the putative dual-function nature of galectin-3 evokes a possible non-classical connection between glycobiology and RNA biology. However, with limited functional evidence of a direct RNA interaction, many molecular-level observations rely on affinity reagents and lack appropriate genetic controls. Thus, evidence of a direct interaction remains elusive. We demonstrate that antibodies raised to endogenous human galectin-3 can isolate RNA-protein crosslinks, but this activity remains insensitive to LGALS3 knock-out. Proteomic characterization of anti-galectin-3 IPs revealed enrichment of galectin-3, but high abundance of hnRNPA2B1, an abundant, well-characterized RNA-binding protein with weak homology to the N-terminal domain of galectin-3, in the isolate. Genetic ablation of HNRNPA2B1, but not LGALS3, eliminates the ability of the anti-galectin-3 antibodies to isolate RNA-protein crosslinks, implying either an indirect interaction or cross-reactivity. To address this, we introduced an epitope tag to the endogenous C-terminal locus of LGALS3. Isolation of the tagged galectin-3 failed to reveal any RNA-protein crosslinks. This result suggests that the galectin-3 does not directly interact with RNA and may be misidentified as an RNA-binding protein, at least in HeLa where the putative RNA associations were first identified. We encourage further investigation of this phenomenon employ gene deletions and, when possible, endogenous epitope tags to achieve the specificity required to evaluate potential interactions.
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Affiliation(s)
- Egan L Peltan
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 269 Campus Drive CCSR 4145 Stanford, CA 94305, United States
- Sarafan ChEM-H, Stanford University, Stanford ChEM-H Building 290 Jane Stanford Way Stanford, CA 94305, United States
| | - Nicholas M Riley
- Sarafan ChEM-H, Stanford University, Stanford ChEM-H Building 290 Jane Stanford Way Stanford, CA 94305, United States
- Department of Chemistry, Stanford University, 333 Campus Drive Stanford, CA 94305, United States
| | - Ryan A Flynn
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, 1 Blackfan Circle, Boston, MA 02445, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, 7 Divinity Ave, Cambridge, MA 02138, United States
| | - David S Roberts
- Sarafan ChEM-H, Stanford University, Stanford ChEM-H Building 290 Jane Stanford Way Stanford, CA 94305, United States
- Department of Chemistry, Stanford University, 333 Campus Drive Stanford, CA 94305, United States
| | - Carolyn R Bertozzi
- Sarafan ChEM-H, Stanford University, Stanford ChEM-H Building 290 Jane Stanford Way Stanford, CA 94305, United States
- Department of Chemistry, Stanford University, 333 Campus Drive Stanford, CA 94305, United States
- Howard Hughes Medical Institute, Stanford University, 279 Campus Drive Room B202 Stanford, CA 94305-5323, United States
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Voss PG, Wang JL. Liquid-liquid phase separation: Galectin-3 in nuclear speckles and ribonucleoprotein complexes. Exp Cell Res 2023; 427:113571. [PMID: 37003559 DOI: 10.1016/j.yexcr.2023.113571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/19/2023] [Accepted: 03/24/2023] [Indexed: 04/03/2023]
Abstract
Nuclear speckles are subcellular structures originally characterized by punctate immunofluorescence staining of the monoclonal antibody SC35, which recognizes an epitope on SRRM2 (serine/arginine repetitive matrix protein 2) and Sfrs2, a member of the SR (serine/arginine-rich) family of splicing factors. Galectin-3 co-localizes with SC35 in nuclear speckles, which represent one group of nuclear bodies that include the nucleolus, Cajal bodies and gems, paraspeckles, etc. Although they appear to have well-delineated physical boundaries, these nuclear bodies are not membrane-bound structures but represent macromolecular assemblies arising from a phenomenon called liquid-liquid phase separation. There has been much recent interest in liquid phase condensation as a newly recognized mechanism by which a cell can organize and compartmentalize subcellular structures with distinct composition. The punctate/speckled staining of galectin-3 with SC3 demonstrates their co-localization in a phase-separated body in vivo, under conditions endogenous to the cell. The purpose of the present review is to summarize the studies that document three key features of galectin-3 for its localization in liquid phase condensates: (a) an intrinsically disordered domain; (b) oligomer formation for multivalent binding; and (c) association with RNA and ribonucleoprotein complexes.
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Affiliation(s)
- Patricia G Voss
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - John L Wang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.
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Yu X, Qian J, Ding L, Yin S, Zhou L, Zheng S. Galectin-1: A Traditionally Immunosuppressive Protein Displays Context-Dependent Capacities. Int J Mol Sci 2023; 24:ijms24076501. [PMID: 37047471 PMCID: PMC10095249 DOI: 10.3390/ijms24076501] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/20/2023] [Accepted: 03/23/2023] [Indexed: 04/03/2023] Open
Abstract
Galectin–Carbohydrate interactions are indispensable to pathogen recognition and immune response. Galectin-1, a ubiquitously expressed 14-kDa protein with an evolutionarily conserved β-galactoside binding site, translates glycoconjugate recognition into function. That galectin-1 is demonstrated to induce T cell apoptosis has led to substantial attention to the immunosuppressive properties of this protein, such as inducing naive immune cells to suppressive phenotypes, promoting recruitment of immunosuppressing cells as well as impairing functions of cytotoxic leukocytes. However, only in recent years have studies shown that galectin-1 appears to perform a pro-inflammatory role in certain diseases. In this review, we describe the anti-inflammatory function of galectin-1 and its possible mechanisms and summarize the existing therapies and preclinical efficacy relating to these agents. In the meantime, we also discuss the potential causal factors by which galectin-1 promotes the progression of inflammation.
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Kapetanakis NI, Busson P. Galectins as pivotal components in oncogenesis and immune exclusion in human malignancies. Front Immunol 2023; 14:1145268. [PMID: 36817445 PMCID: PMC9935586 DOI: 10.3389/fimmu.2023.1145268] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023] Open
Abstract
Galectins are galactoside-binding proteins, exerting numerous functions inside and outside the cell, particularly conferring adaptation to stress factors. For most of them, aberrant expression profiles have been reported in the context of cancer. Albeit not being oncogenic drivers, galectins can be harnessed to exacerbate the malignant phenotype. Their impact on disease establishment and progression is not limited to making cancer cells resistant to apoptosis, but is prominent in the context of the tumor microenvironment, where it fosters angiogenesis, immune escape and exclusion. This review focuses mainly on Gal-1, Gal-3 and Gal-9 for which the involvement in cancer biology is best known. It presents the types of galectin dysregulations, attempts to explain the mechanisms behind them and analyzes the different ways in which they favor tumour growth. In an era where tumour resistance to immunotherapy appears as a major challenge, we highlight the crucial immunosuppressive roles of galectins and the potential therapeutic benefits of combinatorial approaches including galectin inhibition.
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Affiliation(s)
| | - Pierre Busson
- Host-Tumor Interactions in Head and Neck Carcinoma: Exploration and Therapeutic Modulations, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche(UMR) 9018 - METabolic and SYstemic aspects of oncogenesis for new therapeutic approaches (METSY), Gustave Roussy and Université Paris-Saclay, Villejuif, France
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Laderach DJ, Compagno D. Inhibition of galectins in cancer: Biological challenges for their clinical application. Front Immunol 2023; 13:1104625. [PMID: 36703969 PMCID: PMC9872792 DOI: 10.3389/fimmu.2022.1104625] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 12/16/2022] [Indexed: 01/11/2023] Open
Abstract
Galectins play relevant roles in tumor development, progression and metastasis. Accordingly, galectins are certainly enticing targets for medical intervention in cancer. To date, however, clinical trials based on galectin inhibitors reported inconclusive results. This review summarizes the galectin inhibitors currently being evaluated and discusses some of the biological challenges that need to be addressed to improve these strategies for the benefit of cancer patients.
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Affiliation(s)
- Diego José Laderach
- Molecular and Functional Glyco-Oncology Laboratory, Instituto de Química Biológica de la Facutad de Ciencias Exactas y Naturales (IQUIBICEN-CONICET), Buenos Aires, Argentina,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina,Departamento de Ciencias Básicas, Universidad Nacional de Luján, Luján, Argentina,*Correspondence: Diego José Laderach,
| | - Daniel Compagno
- Molecular and Functional Glyco-Oncology Laboratory, Instituto de Química Biológica de la Facutad de Ciencias Exactas y Naturales (IQUIBICEN-CONICET), Buenos Aires, Argentina,Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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Verkerke H, Dias-Baruffi M, Cummings RD, Arthur CM, Stowell SR. Galectins: An Ancient Family of Carbohydrate Binding Proteins with Modern Functions. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2442:1-40. [PMID: 35320517 DOI: 10.1007/978-1-0716-2055-7_1] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Galectins are a large family of carbohydrate binding proteins with members in nearly every lineage of multicellular life. Through tandem and en-mass genome duplications, over 15 known vertebrate galectins likely evolved from a single common ancestor extant in pre-chordate lineages. While galectins have divergently evolved numerous functions, some of which do not involve carbohydrate recognition, the vast majority of the galectins have retained the conserved ability to bind variably modified polylactosamine (polyLacNAc) residues on glycans that modify proteins and lipids on the surface of host cells and pathogens. In addition to their direct role in microbial killing, many proposed galectin functions in the immune system and cancer involve crosslinking glycosylated receptors and modifying signaling pathways or sensitivity to antigen from the outside in. However, a large body of work has uncovered intracellular galectin functions mediated by carbohydrate- and non-carbohydrate-dependent interactions. In the cytoplasm, galectins can tune intracellular kinase and G-protein-coupled signaling cascades important for nutrient sensing, cell cycle progression, and transformation. Particularly, but interconnected pathways, cytoplasmic galectins serve the innate immune system as sensors of endolysosomal damage, recruiting and assembling the components of autophagosomes during intracellular infection through carbohydrate-dependent and -independent activities. In the nucleus, galectins participate in pre-mRNA splicing perhaps through interactions with non-coding RNAs required for assembly of spliceosomes. Together, studies of galectin function paint a picture of a functionally dynamic protein family recruited during eons of evolution to regulate numerous essential cellular processes in the context of multicellular life.
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Affiliation(s)
- Hans Verkerke
- Joint Program in Transfusion Medicine, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Harvard Glycomics Center, Harvard Medical School, Boston, MA, USA
| | - Marcelo Dias-Baruffi
- Department of Clinical Analysis, Toxicological and Bromatological, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | | | - Connie M Arthur
- Joint Program in Transfusion Medicine, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Harvard Glycomics Center, Harvard Medical School, Boston, MA, USA
| | - Sean R Stowell
- Joint Program in Transfusion Medicine, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. .,Harvard Glycomics Center, Harvard Medical School, Boston, MA, USA.
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Voss PG, Haudek KC, Patterson RJ, Wang JL. Galectin-3-U1 snRNP Complexes Initiate Splicing Activity in U1-Depleted Nuclear Extracts. Methods Mol Biol 2022; 2442:713-726. [PMID: 35320554 DOI: 10.1007/978-1-0716-2055-7_38] [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] [Indexed: 06/14/2023]
Abstract
Fractionation of HeLa cell nuclear extracts by glycerol gradient centrifugation separates endogenous uracil-rich small nuclear ribonucleoprotein complexes (U snRNP) into numerous particles sedimenting from 7S to greater than 60S. Complexes sedimenting at 10S contain a single U snRNP (U1 snRNP) and galectin-3. Addition of antibodies specific for galectin-3 to fractions containing these 10S complexes coprecipitates U1 snRNP, indicating that a fraction of the U1 snRNP is associated with this galectin. Galectin-3 has been shown by depletion-reconstitution studies to be an integral splicing component involved both in spliceosome assembly and splicing activity. The first step in initiation of spliceosome assembly is binding of U1 snRNP to the 5' splice site of the premessenger RNA substrate. The finding that U1 snRNP and galectin-3 are associated in splicing extracts hints that this complex affords a potential entry point for galectin-3 into the splicing pathway. Addition of U1 snRNP-galectin-3 complexes immunoselected from the 10S region of glycerol gradients to a U1-depleted nuclear extract initiates splicing activity with the formation of splicing intermediates and mature mRNA. This chapter describes the materials and methods for these experiments that document galectin-3-U1 snRNP complexes initiate the splicing reaction in a U1-depleted nuclear extract.
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Affiliation(s)
- Patricia G Voss
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Kevin C Haudek
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Ronald J Patterson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - John L Wang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.
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Unraveling How Tumor-Derived Galectins Contribute to Anti-Cancer Immunity Failure. Cancers (Basel) 2021; 13:cancers13184529. [PMID: 34572756 PMCID: PMC8469970 DOI: 10.3390/cancers13184529] [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: 07/17/2021] [Revised: 08/16/2021] [Accepted: 08/24/2021] [Indexed: 12/15/2022] Open
Abstract
Simple Summary This review compiles our current knowledge of one of the main pathways activated by tumors to escape immune attack. Indeed, it integrates the current understanding of how tumor-derived circulating galectins affect the elicitation of effective anti-tumor immunity. It focuses on several relevant topics: which are the main galectins produced by tumors, how soluble galectins circulate throughout biological liquids (taking a body-settled gradient concentration into account), the conditions required for the galectins’ functions to be accomplished at the tumor and tumor-distant sites, and how the physicochemical properties of the microenvironment in each tissue determine their functions. These are no mere semantic definitions as they define which functions can be performed in said tissues instead. Finally, we discuss the promising future of galectins as targets in cancer immunotherapy and some outstanding questions in the field. Abstract Current data indicates that anti-tumor T cell-mediated immunity correlates with a better prognosis in cancer patients. However, it has widely been demonstrated that tumor cells negatively manage immune attack by activating several immune-suppressive mechanisms. It is, therefore, essential to fully understand how lymphocytes are activated in a tumor microenvironment and, above all, how to prevent these cells from becoming dysfunctional. Tumors produce galectins-1, -3, -7, -8, and -9 as one of the major molecular mechanisms to evade immune control of tumor development. These galectins impact different steps in the establishment of the anti-tumor immune responses. Here, we carry out a critical dissection on the mechanisms through which tumor-derived galectins can influence the production and the functionality of anti-tumor T lymphocytes. This knowledge may help us design more effective immunotherapies to treat human cancers.
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Galectins in prostate and bladder cancer: tumorigenic roles and clinical opportunities. Nat Rev Urol 2020; 16:433-445. [PMID: 31015643 DOI: 10.1038/s41585-019-0183-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Advanced prostate and bladder cancer are two outstanding unmet medical needs for urological oncologists. The high prevalence of these tumours, lack of effective biomarkers and limited effective treatment options highlight the importance of basic research in these diseases. Galectins are a family of β-galactoside-binding proteins that are frequently altered (upregulated or downregulated) in a wide range of tumours and have roles in different stages of tumour development and progression, including immune evasion. In particular, altered expression levels of different members of the galectin family have been reported in prostate and bladder cancers, which, together with the aberrant glycosylation patterns found in tumour cells and the constituent cell types of the tumour microenvironment, can result in malignant transformation and tumour progression. Understanding the roles of galectin family proteins in the development and progression of prostate and bladder cancer could yield key insights to inform the clinical management of these diseases.
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Abel WF, Funk CR, Blenda AV. Galectins in the Pathogenesis of Cerebrovascular Accidents: An Overview. J Exp Neurosci 2019; 13:1179069519836794. [PMID: 31007530 PMCID: PMC6458655 DOI: 10.1177/1179069519836794] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 02/19/2019] [Indexed: 01/04/2023] Open
Abstract
Due to limitations of neuroimaging, such as the isodense appearance of blood to neuronal tissue in subacute hemorrhagic stroke, a body of studies have been performed to evaluate candidate biomarkers which may aid in accurate determination of cerebrovascular accident type. Beyond aiding in the delineation of stroke cause, biomarkers could also confer useful prognostic information to help clinicians plan use of resources. One of the candidate biomarkers studied for detection of cerebrovascular accident (CVA) includes a class of proteins called galectins. Galectins bind β-galactoside through a highly conserved carbohydrate recognition domain, endowing an ability to interact with carbohydrate moieties on glycoproteins, some of which are relevant to CVA response. Furthermore, galectins-1, -2, -3, -9, and -12 are expressed in tissues relevant to CVA, and some exhibit characteristics (eg, extracellular secretion) that could render feasible their detection in serum. Galectins-1 and -3 appear to have the largest amounts of preclinical evidence, consistently demonstrating increased activity and expression levels during CVA. However, a lack of standardization of biochemical assays across cohort studies limits further translation of these basic science studies. This review aims to increase awareness of the biochemical roles of galectins in CVA, while also highlighting challenges and remaining questions preventing the translation of basic science observations into a clinically useful test.
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Affiliation(s)
- William F Abel
- University of South Carolina School of Medicine Greenville, Greenville, SC, USA
| | | | - Anna V Blenda
- University of South Carolina School of Medicine Greenville, Greenville, SC, USA
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12
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Abstract
Galectins are carbohydrate-binding proteins that are involved in many physiological functions, such as inflammation, immune responses, cell migration, autophagy and signalling. They are also linked to diseases such as fibrosis, cancer and heart disease. How such a small family of only 15 members can have such widespread effects remains a conundrum. In this Cell Science at a Glance article, we summarise recent literature on the many cellular activities that have been ascribed to galectins. As shown on the accompanying poster, these include carbohydrate-independent interactions with cytosolic or nuclear targets and carbohydrate-dependent interactions with extracellular glycoconjugates. We discuss how these intra- and extracellular activities might be linked and point out the importance of unravelling molecular mechanisms of galectin function to gain a true understanding of their contributions to the physiology of the cell. We close with a short outlook on the organismal functions of galectins and a perspective on the major challenges in the field.
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Affiliation(s)
- Ludger Johannes
- Institut Curie, PSL Research University, Cellular and Chemical Biology unit, U1143 INSERM, UMR3666 CNRS, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Ralf Jacob
- Philipps-Universität Marburg, Institut für Zytobiologie, Robert-Koch-Str. 6, 35037 Marburg, Germany
| | - Hakon Leffler
- Sect. MIG (Microbiology, Immunology, Glycobiology), Dept Laboratory Medicine, Lund University, POB 117, 22100 Lund, Sweden
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Enhanced cortical bone expansion in Lgals3-deficient mice during aging. Bone Res 2018; 6:7. [PMID: 30886760 PMCID: PMC6416267 DOI: 10.1038/s41413-017-0003-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/13/2017] [Accepted: 08/28/2017] [Indexed: 12/12/2022] Open
Abstract
Imbalances between bone formation and bone resorption, which can occur due to aging or sex hormone deprivation, result in decreased bone mass and an increased risk of fracture. Previous studies have suggested that the β-galactoside binding lectin, galectin-3, is involved in bone remodeling. We compared bone parameters of mice having null alleles of the galectin-3 gene (Lgals3-KO) with those of their wild-type littermates. Lgals3 deficiency increased cortical bone expansion at 36 weeks (wk) and preserved or enhanced bone mass in both male and female mutant mice. In addition, female Lgals3-KO mice were protected from age-related loss of trabecular bone. Histomorphometry and ex vivo primary cell differentiation assays showed increased osteoblastogenesis with little-to-no effect on osteoclastogenesis, suggesting the increased bone mass phenotype is primarily due to increased anabolism. Our study identifies galectin-3 as a negative regulator of bone formation and suggests that disruption of galectin-3 may be useful in preventing bone loss during aging. Researchers have identified a promising new drug target to reduce bone loss during aging, a protein called galectin-3. Bones undergo lifelong remodeling via resorption of old bone and generation of new bone. With aging, the balance tips towards resorption, weakening bones. Galectin-3 was known to be involved in bone remodeling and levels increased with age. Bart Williams and co-workers at the Van Andel Research Institute in Grand Rapids, USA, investigated whether the age-related increase in galectin-3 increased bone loss. Using mice lacking the gene encoding galectin-3, the researchers measured bone mass at different ages. In older mice, bone mass was preserved or even enhanced. Further investigation of bone cells showed the increase was probably due to increased bone formation, rather than decreased bone resorption. The researchers conclude that disrupting galectin-3 may help to prevent aging-related bone loss.
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Galectin-3 is a non-classic RNA binding protein that stabilizes the mucin MUC4 mRNA in the cytoplasm of cancer cells. Sci Rep 2017; 7:43927. [PMID: 28262838 PMCID: PMC5338267 DOI: 10.1038/srep43927] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 02/01/2017] [Indexed: 12/22/2022] Open
Abstract
Pancreatic cancer cells express high levels of MUC1, MUC4 and MUC16 mRNAs that encode membrane-bound mucins. These mRNAs share unusual features such as a long half-life. However, it remains unknown how mucin mRNA stability is regulated. Galectin-3 (Gal-3) is an endogenous lectin playing important biological functions in epithelial cells. Gal-3 is encoded by LGALS3 which is up-regulated in pancreatic cancer. Despite the absence of a RNA-recognition motif, Gal-3 interacts indirectly with pre-mRNAs in the nucleus and promotes constitutive splicing. However a broader role of Gal-3 in mRNA fate is unexplored. We report herein that Gal-3 increases MUC4 mRNA stability through an intermediate, hnRNP-L which binds to a conserved CA repeat element in the 3′UTR in a Gal-3 dependent manner and also controls Muc4 mRNA levels in epithelial tissues of Gal3−/− mice. Gal-3 interacts with hnRNP-L in the cytoplasm, especially during cell mitosis, but only partly associates with protein markers of P-Bodies or Stress Granules. By RNA-IP plus RNA-seq analysis and imaging, we demonstrate that Gal-3 binds to mature spliced MUC4 mRNA in the perinuclear region, probably in hnRNP-L-containing RNA granules. Our findings highlight a new role for Gal-3 as a non-classic RNA-binding protein that regulates MUC4 mRNA post-transcriptionally.
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15
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Fritsch K, Mernberger M, Nist A, Stiewe T, Brehm A, Jacob R. Galectin-3 interacts with components of the nuclear ribonucleoprotein complex. BMC Cancer 2016; 16:502. [PMID: 27435226 PMCID: PMC4952364 DOI: 10.1186/s12885-016-2546-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 07/11/2016] [Indexed: 01/15/2023] Open
Abstract
Background The multifunctional β-galactoside-binding protein galectin-3 is found in many distinct subcellular compartments including the cell nucleus. Expression and distribution of galectin-3 between the cell nucleus and the cytosol changes during cell differentiation and cancer development. Nuclear functions of galectin-3 and how they contribute to tumorigenesis are not understood. Methods In order to identify nuclear galectin-3 interaction partners, we used affinity chromatography and co-immunoprecipitation. Spatial proximity in the nucleus was assessed by immunofluorescence and proximity ligation assay. We also investigated the function of galectin-3 on mRNA-export by fluorescence in situ hybridization and on mRNA-processing by RNA-sequencing. Results The heterogeneous ribonucleoprotein particle component hnRNPA2B1 was identified as a novel galectin-3 binding protein that associates with the lectin in a lactose-dependent manner in the cell nucleus. Specific individual depletion of galectin-3 does not affect the mRNA distribution between cytoplasm and nucleus. A significant alteration of this distribution was observed after combined depletion of galectin-1 and −3. However, silencing of galectin-3 was sufficient to alter the splicing patterns of several genes. Conclusions Galectin-3 and hnRNPA2B1 interact as members of the early splicing machinery. Galectin-3 and −1 have redundant functions in mRNA transport and at least in part in mRNA splicing. RNA-sequencing data points to a specific function of the hnRNPA2B1/galectin-3 interaction in the processing of transcripts coding for the nuclear oncoprotein SET. Electronic supplementary material The online version of this article (doi:10.1186/s12885-016-2546-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katharina Fritsch
- Department of Cell Biology and Cell Pathology, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35037, Marburg, Germany
| | - Marco Mernberger
- Institute of Molecular Oncology, Philipps-Universität Marburg, Marburg, Germany
| | - Andrea Nist
- Genomics Core Facility, Philipps-Universität Marburg, Marburg, Germany
| | - Thorsten Stiewe
- Institute of Molecular Oncology, Philipps-Universität Marburg, Marburg, Germany.,Genomics Core Facility, Philipps-Universität Marburg, Marburg, Germany
| | - Alexander Brehm
- Institute for Molecular Biology and Tumor Research, Philipps-Universität Marburg, Marburg, Germany
| | - Ralf Jacob
- Department of Cell Biology and Cell Pathology, Philipps-Universität Marburg, Robert-Koch-Str. 6, D-35037, Marburg, Germany.
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Haudek KC, Voss PG, Wang JL, Patterson RJ. A 10S galectin-3-U1 snRNP complex assembles into active spliceosomes. Nucleic Acids Res 2016; 44:6391-7. [PMID: 27105840 PMCID: PMC5291251 DOI: 10.1093/nar/gkw303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 04/12/2016] [Indexed: 12/13/2022] Open
Abstract
In previous studies, we reported that fractionation of HeLa cell nuclear extracts on glycerol gradients revealed an endogenous ∼10S particle that contained galectin-3 and U1 snRNP and this particle was sufficient to load the galectin polypeptide onto a pre-mRNA substrate. We now document that this interaction between the galectin-3–U1 snRNP particle and the pre-mRNA results in a productive spliceosomal complex, leading to intermediates and products of the splicing reaction. Nuclear extracts were depleted of U1 snRNP with a concomitant loss of splicing activity. Splicing activity in the U1-depleted extract can be reconstituted by the galectin-3–U1 snRNP particle, isolated by immunoprecipitation of the 10S region (fractions 3–5) of the glycerol gradient with anti-galectin-3 antibodies. In contrast, parallel anti-galectin-3 immunoprecipitation of free galectin-3 molecules not in a complex with U1 snRNP (fraction 1 of the same gradient), failed to restore splicing activity. These results indicate that the galectin-3–U1 snRNP-pre-mRNA ternary complex is a functional E complex and that U1 snRNP is required to assemble galectin-3 onto an active spliceosome.
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Affiliation(s)
- Kevin C Haudek
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Patricia G Voss
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - John L Wang
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Ronald J Patterson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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Deák M, Hornung Á, Novák J, Demydenko D, Szabó E, Czibula Á, Fajka-Boja R, Kriston-Pál É, Monostori É, Kovács L. Novel role for galectin-1 in T-cells under physiological and pathological conditions. Immunobiology 2015; 220:483-9. [DOI: 10.1016/j.imbio.2014.10.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 01/09/2023]
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18
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Abstract
Galectins are an evolutionarily ancient family of glycan-binding proteins (GBPs) and are found in all animals. Although they were discovered over 30 years ago, ideas about their biological functions continue to evolve. Current evidence indicates that galectins, which are the only known GBPs that occur free in the cytoplasm and extracellularly, are involved in a variety of intracellular and extracellular pathways contributing to homeostasis, cellular turnover, cell adhesion, and immunity. Here we review evolving insights into galectin biology from a historical perspective and explore current evidence regarding biological roles of galectins.
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19
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Takaku S, Yanagisawa H, Watabe K, Horie H, Kadoya T, Sakumi K, Nakabeppu Y, Poirier F, Sango K. GDNF promotes neurite outgrowth and upregulates galectin-1 through the RET/PI3K signaling in cultured adult rat dorsal root ganglion neurons. Neurochem Int 2013; 62:330-9. [DOI: 10.1016/j.neuint.2013.01.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 12/28/2012] [Accepted: 01/08/2013] [Indexed: 01/22/2023]
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20
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Voss PG, Haudek KC, Patterson RJ, Wang JL. Inhibition of Cell-Free Splicing by Saccharides That Bind Galectins and SR Proteins. J Carbohydr Chem 2012. [DOI: 10.1080/07328303.2012.666688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Patricia G. Voss
- a Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , MI , 48824 , USA
| | - Kevin C. Haudek
- a Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , MI , 48824 , USA
| | - Ronald J. Patterson
- b Department of Microbiology and Molecular Genetics , Michigan State University , East Lansing , MI , 48824 , USA
| | - John L. Wang
- a Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , MI , 48824 , USA
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21
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Lefranc F, Mathieu V, Kiss R. Galectin-1-mediated biochemical controls of melanoma and glioma aggressive behavior. World J Biol Chem 2011; 2:193-201. [PMID: 21949569 PMCID: PMC3178756 DOI: 10.4331/wjbc.v2.i9.193] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 08/23/2011] [Accepted: 08/30/2011] [Indexed: 02/06/2023] Open
Abstract
Gliomas and melanomas are associated with dismal prognosis because of their marked intrinsic resistance to proapoptotic stimuli, such as conventional chemotherapy and radiotherapy, as well as their ability to escape immune cell attacks. In addition, gliomas and melanomas display pronounced neoangiogenesis. Galectin-1 is a hypoxia-sensitive protein, which is abundantly secreted by glioma and melanoma cells, which displays marked proangiogenic effects. It also provides immune tolerogenic environments to melanoma and glioma cells through the killing of activated T cells that attack these tumor cells. Galectin-1 protects glioma and melanoma cells against cytotoxic insults (including chemotherapy and radiotherapy) through a direct role in the unfolded protein response. Altogether, these facts clearly point to galectin-1 as an important target to be combated in gliomas and melanomas in order to: (1) weaken the defenses of these two types of cancers against radiotherapy, chemotherapy and immunotherapy/vaccine therapy; and (2) reinforce antiangiogenic therapies. In the present article, we review the biochemical and molecular biology-related pathways controlled by galectin-1, which are actually beneficial for melanoma and glioma cells, and therefore detrimental for melanoma and glioma patients.
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Affiliation(s)
- Florence Lefranc
- Florence Lefranc, Véronique Mathieu, Robert Kiss, Laboratory of Toxicology, Faculty of Pharmacy, Université Libre de Bruxelles, Brussels 1050, Belgium
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22
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Abstract
Although members of the serine (S)- and arginine (R)-rich splicing factor family (SR proteins) were initially purified on the basis of their splicing activity in the nucleus, there is recent documentation that they exhibit carbohydrate-binding activity at the cell surface. In contrast, galectins were isolated on the basis of their saccharide-binding activity and cell surface localization. Surprisingly, however, two members (galectin-1 and galectin-3) can be found in association with nuclear ribonucleoprotein complexes including the spliceosome and, using a cell-free assay, have been shown to be required splicing factors. Thus, despite the difference in terms of their original points of interest, it now appears that members of the two protein families share four key properties: (a) nuclear and cytoplasmic distribution; (b) pre-mRNA splicing activity; (c) carbohydrate-binding activity; and (d) cell surface localization in specific cells. These findings provoke stimulating questions regarding the relationship between splicing factors in the nucleus and carbohydrate-binding proteins at the cell surface.
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Affiliation(s)
- Kevin C Haudek
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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23
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Haudek KC, Spronk KJ, Voss PG, Patterson RJ, Wang JL, Arnoys EJ. Dynamics of galectin-3 in the nucleus and cytoplasm. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1800:181-9. [PMID: 19616076 PMCID: PMC2815258 DOI: 10.1016/j.bbagen.2009.07.005] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 07/06/2009] [Indexed: 11/29/2022]
Abstract
This review summarizes selected studies on galectin-3 (Gal3) as an example of the dynamic behavior of a carbohydrate-binding protein in the cytoplasm and nucleus of cells. Within the 15-member galectin family of proteins, Gal3 (M(r) approximately 30,000) is the sole representative of the chimera subclass in which a proline- and glycine-rich NH(2)-terminal domain is fused onto a COOH-terminal carbohydrate recognition domain responsible for binding galactose-containing glycoconjugates. The protein shuttles between the cytoplasm and nucleus on the basis of targeting signals that are recognized by importin(s) for nuclear localization and exportin-1 (CRM1) for nuclear export. Depending on the cell type, specific experimental conditions in vitro, or tissue location, Gal3 has been reported to be exclusively cytoplasmic, predominantly nuclear, or distributed between the two compartments. The nuclear versus cytoplasmic distribution of the protein must reflect, then, some balance between nuclear import and export, as well as mechanisms of cytoplasmic anchorage or binding to a nuclear component. Indeed, a number of ligands have been reported for Gal3 in the cytoplasm and in the nucleus. Most of the ligands appear to bind Gal3, however, through protein-protein interactions rather than through protein-carbohydrate recognition. In the cytoplasm, for example, Gal3 interacts with the apoptosis repressor Bcl-2 and this interaction may be involved in Gal3's anti-apoptotic activity. In the nucleus, Gal3 is a required pre-mRNA splicing factor; the protein is incorporated into spliceosomes via its association with the U1 small nuclear ribonucleoprotein (snRNP) complex. Although the majority of these interactions occur via the carbohydrate recognition domain of Gal3 and saccharide ligands such as lactose can perturb some of these interactions, the significance of the protein's carbohydrate-binding activity, per se, remains a challenge for future investigations.
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Affiliation(s)
- Kevin C. Haudek
- Department of Biochemistry and Molecular Biology Michigan State University, East Lansing, MI 48824
| | - Kimberly J. Spronk
- Department of Chemistry and Biochemistry Calvin College, Grand Rapids, MI 49546
| | - Patricia G. Voss
- Department of Biochemistry and Molecular Biology Michigan State University, East Lansing, MI 48824
| | - Ronald J. Patterson
- Department of Microbiology and Molecular Genetics Michigan State University, East Lansing, MI 48824
| | - John L. Wang
- Department of Biochemistry and Molecular Biology Michigan State University, East Lansing, MI 48824
| | - Eric J. Arnoys
- Department of Chemistry and Biochemistry Calvin College, Grand Rapids, MI 49546
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24
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Haudek KC, Voss PG, Locascio LE, Wang JL, Patterson RJ. A mechanism for incorporation of galectin-3 into the spliceosome through its association with U1 snRNP. Biochemistry 2009; 48:7705-12. [PMID: 19603745 DOI: 10.1021/bi900071b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previously, we showed that galectin-1 and galectin-3 are redundant pre-mRNA splicing factors associated with the spliceosome throughout the splicing pathway. Here we present evidence for the association of galectin-3 with snRNPs outside of the spliceosome (i.e., in the absence of pre-mRNA splicing substrate). Immunoprecipitation of HeLa nuclear extract with anti-galectin-3 resulted in the coprecipitation of the five spliceosomal snRNAs, core Sm polypeptides, and the U1-specific protein, U1 70K. When nuclear extract was fractionated on glycerol gradients, some galectin-3 molecules cosedimented with snRNP complexes. This cosedimentation represents bona fide galectin-3--snRNP complexes as (i) immunoprecipitation of gradient fractions with anti-galectin-3 yielded several complexes with varying ratios of snRNAs and associated proteins and (ii) the distribution of galectin-3--snRNP complexes was altered when the glycerol gradient was sedimented in the presence of lactose, a galectin ligand. A complex at approximately 10S showed an association of galectin-3 with U1 snRNP that was sensitive to treatment with ribonuclease A. We tested the ability of this U1 snRNP to recognize an exogenous pre-mRNA substrate. Under conditions that assemble early splicing complexes, we found this isolated galectin-3--U1 snRNP particle was sufficient to load galectin-3 onto a pre-mRNA substrate, but not onto a control RNA lacking splice sites. Pretreatment of the U1 snRNP with micrococcal nuclease abolished the assembly of galectin-3 onto this early complex. These data identify galectin-3 as a polypeptide associated with snRNPs in the absence of splicing substrate and describe a mechanism for the assembly of galectin-3 onto the forming spliceosome.
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Affiliation(s)
- Kevin C Haudek
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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25
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Loser K, Sturm A, Voskort M, Kupas V, Balkow S, Auriemma M, Sternemann C, Dignass AU, Luger TA, Beissert S. Galectin-2 suppresses contact allergy by inducing apoptosis in activated CD8+ T cells. THE JOURNAL OF IMMUNOLOGY 2009; 182:5419-29. [PMID: 19380789 DOI: 10.4049/jimmunol.0802308] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Galectins, a family of structurally related beta-galactoside-binding proteins, are expressed by various cells of the immune systems and seem to be important for the regulation of immune responses and immune cell homeostasis. Since it has been demonstrated that galectin-2 regulates cell-mediated inflammatory bowel disease and colitis in mice, we intended to investigate the role of galectin-2 in inflammatory cutaneous T cell-mediated immune responses. To address this issue, groups of naive mice were sensitized to the contact allergen 2,4-dinitro-1-fluorobenzene and systemically treated with galectin-2 to analyze the effects of galectin-2 on contact allergy. Here we show that galectin-2 is expressed in murine skin and is up-regulated upon cutaneous inflammation. Interestingly, treatment of mice with galectin-2 significantly reduced the contact allergy response. This effect was long-lasting since rechallenge of galectin-2-treated mice after a 14-day interval still resulted in a decreased ear swelling. We were able to demonstrate that galectin-2 induced a reduction of MHC class I-restricted immune responses in the treated animals, which was mediated by the induction of apoptosis specifically in activated CD8(+) T cells. Additionally, we report that the galectin-2-binding protein CD29 is up-regulated on the surface of activated CD8(+) T cells compared with naive CD8(+) T cells or CD4(+) T cells, suggesting that increased galectin-2/CD29 signaling might be responsible for the proapoptotic effects of galectin-2 on activated CD8(+) T cells. Taken together, these data indicate that galectin-2 may represent a novel therapeutic alternative for the treatment of CD8-mediated inflammatory disorders such as contact allergy.
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Affiliation(s)
- Karin Loser
- Department of Dermatology, University of Münster, Münster, Germany.
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26
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St-Pierre Y, Biron-Pain K, Campion C, Lavoie G, Bouchard F, Couillard J. Potential directions for drug development against galectin-7 in cancer. Expert Opin Drug Discov 2009; 4:611-20. [DOI: 10.1517/17460440902926399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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27
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Tsai CM, Chiu YK, Hsu TL, Lin IY, Hsieh SL, Lin KI. Galectin-1 promotes immunoglobulin production during plasma cell differentiation. THE JOURNAL OF IMMUNOLOGY 2008; 181:4570-9. [PMID: 18802059 DOI: 10.4049/jimmunol.181.7.4570] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Galectin-1, a beta-galactoside-binding soluble lectin, has been implicated in regulating immune system homeostasis. We investigated the function of galectin-1 in plasma cell differentiation and found that it is induced in primary murine and human differentiating B cells. B lymphocyte-induced maturation protein-1 (Blimp-1), a master regulator for plasma cell differentiation, was necessary and sufficient to induce galectin-1 expression. Notably, ectopic expression of galectin-1 in mature B cells increased Ig mu-chain transcript levels as well as the overall level of Ig production. This function of galectin-1 was dependent on binding to cell surface glycosylated counter receptors, as a galectin-1 mutant deficient in beta-galactoside binding showed diminished ability to promote Ig production. Extracellular galectin-1 bound more significantly to mature B cells than to plasma cells. Lastly, we found that the sugar compound N-acetyllactosamine blocked the binding of galectin-1 to murine splenic B cells and inhibited their differentiation. Taken together, these data are the first to demonstrate a role for galectin-1 in promoting Ig production during plasma cell differentiation.
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Affiliation(s)
- Chih-Ming Tsai
- Institute and Department of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan
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28
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Rapoport EM, Kurmyshkina OV, Bovin NV. Mammalian galectins: structure, carbohydrate specificity, and functions. BIOCHEMISTRY (MOSCOW) 2008; 73:393-405. [PMID: 18457568 DOI: 10.1134/s0006297908040032] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Galectins are a family of beta-galactoside binding lectins, homological by a sequence of the carbohydrate-binding site. In this review literature data about structure and carbohydrate specificity of galectins are discussed. The role of galectins in the regulation of cell adhesion in immune response, inflammation, and cancer progression is considered.
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Affiliation(s)
- E M Rapoport
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
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29
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Voss PG, Gray RM, Dickey SW, Wang W, Park JW, Kasai KI, Hirabayashi J, Patterson RJ, Wang JL. Dissociation of the carbohydrate-binding and splicing activities of galectin-1. Arch Biochem Biophys 2008; 478:18-25. [PMID: 18662664 DOI: 10.1016/j.abb.2008.07.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2008] [Revised: 06/28/2008] [Accepted: 07/08/2008] [Indexed: 01/12/2023]
Abstract
Galectin-1 (Gal1) and galectin-3 (Gal3) are two members of a family of carbohydrate-binding proteins that are found in the nucleus and that participate in pre-mRNA splicing assayed in a cell-free system. When nuclear extracts (NE) of HeLa cells were subjected to adsorption on a fusion protein containing glutathione S-transferase (GST) and Gal3, the general transcription factor II-I (TFII-I) was identified by mass spectrometry as one of the polypeptides specifically bound. Lactose and other saccharide ligands of the galectins inhibited GST-Gal3 pull-down of TFII-I while non-binding carbohydrates failed to yield the same effect. Similar results were also obtained using GST-Gal1. Site-directed mutants of Gal1, expressed and purified as GST fusion proteins, were compared with the wild-type (WT) in three assays: (a) binding to asialofetuin-Sepharose as a measure of the carbohydrate-binding activity; (b) pull-down of TFII-I from NE; and (c) reconstitution of splicing in NE depleted of galectins as a test of the in vitro splicing activity. The binding of GST-Gal1(N46D) to asialofetuin-Sepharose was less than 10% of that observed for GST-Gal1(WT), indicating that the mutant was deficient in carbohydrate-binding activity. In contrast, both GST-Gal1(WT) and GST-Gal1(N46D) were equally efficient in pull-down of TFII-I and in reconstitution of splicing activity in the galectin-depleted NE. Moreover, while the splicing activity of the wild-type protein can be inhibited by saccharide ligands, the carbohydrate-binding deficient mutant was insensitive to such inhibition. Together, all of the results suggest that the carbohydrate-binding and the splicing activities of Gal1 can be dissociated and therefore, saccharide-binding, per se, is not required for the splicing activity.
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Affiliation(s)
- Patricia G Voss
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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30
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Le Mercier M, Mathieu V, Haibe-Kains B, Bontempi G, Mijatovic T, Decaestecker C, Kiss R, Lefranc F. Knocking down galectin 1 in human hs683 glioblastoma cells impairs both angiogenesis and endoplasmic reticulum stress responses. J Neuropathol Exp Neurol 2008; 67:456-69. [PMID: 18431251 DOI: 10.1097/nen.0b013e318170f892] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Galectin (Gal) 1 is a hypoxia-regulated proangiogenic factor that also directly participates in glioblastoma cell migration. To determine how Gal-1 exerts its proangiogenic effects, we investigated Gal-1 signaling in the human Hs683 glioblastoma cell line. Galectin 1 signals through the endoplasmic reticulum transmembrane kinase/ribonuclease inositol-requiring 1alpha, which regulates the expression of oxygen-regulated protein 150. Oxygen-regulated protein 150 controls vascular endothelial growth factor maturation. Galectin 1 also modulates the expression of 7 other hypoxia-related genes (i.e. CTGF, ATF3, PPP1R15A, HSPA5, TRA1, and CYR61) that are implicated in angiogenesis. Decreasing Gal-1 expression in Hs683 orthotopic xenografts in mouse brains by siRNA administration impaired endoplasmic reticulum stress and enhanced the therapeutic benefits of the proautophagic drug temozolomide. These results suggest that decreasing Gal-1 expression (e.g. through brain delivery of nonviral infusions of anti-Gal-1 siRNA in patients) can represent an additional therapeutic strategy for glioblastoma.
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Affiliation(s)
- Marie Le Mercier
- Laboratory of Toxicology, Institute of Pharmacy, Free University of Brussels, Brussels, Belgium
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31
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Gray RM, Davis MJ, Ruby KM, Voss PG, Patterson RJ, Wang JL. Distinct effects on splicing of two monoclonal antibodies directed against the amino-terminal domain of galectin-3. Arch Biochem Biophys 2008; 475:100-8. [PMID: 18455493 DOI: 10.1016/j.abb.2008.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Revised: 04/11/2008] [Accepted: 04/13/2008] [Indexed: 11/25/2022]
Abstract
Previous experiments had established that galectin-3 (Gal3) is a factor involved in cell-free splicing of pre-mRNA. Addition of monoclonal antibody NCL-GAL3, whose epitope maps to the NH2-terminal 14 amino acids of Gal3, to a splicing-competent nuclear extract inhibited the splicing reaction. In contrast, monoclonal antibody anti-Mac-2, whose epitope maps to residues 48-100 containing multiple repeats of a 9-residue motif PGAYPGXXX, had no effect on splicing. Consistent with the notion that this region bearing the PGAYPGXXX repeats is sequestered through interaction with the splicing machinery and is inaccessible to the anti-Mac-2 antibody, a synthetic peptide containing three perfect repeats of the sequence PGAYPGQAP (27-mer) inhibited the splicing reaction, mimicking a dominant-negative mutant. Addition of a peptide corresponding to a scrambled sequence of the same composition (27-mer-S) failed to yield the same effect. Finally, GST-hGal3(1-100), a fusion protein containing glutathione-S-transferase and a portion of the Gal3 polypeptide including the PGAYPGXXX repeats, also exhibited a dominant-negative effect on splicing.
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Affiliation(s)
- Richard M Gray
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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32
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Mazurek N, Sun YJ, Liu KF, Gilcrease MZ, Schober W, Nangia-Makker P, Raz A, Bresalier RS. Phosphorylated galectin-3 mediates tumor necrosis factor-related apoptosis-inducing ligand signaling by regulating phosphatase and tensin homologue deleted on chromosome 10 in human breast carcinoma cells. J Biol Chem 2007; 282:21337-48. [PMID: 17420249 DOI: 10.1074/jbc.m608810200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Galectin-3 (GAL3), a beta-galactoside-binding lectin, confers chemoresistance to a wide variety of cancer cell types. It may exhibit anti- or pro-apoptotic activity depending on the nature of the stimulus. We report here that introducing phosphorylated galectin-3 (P-GAL3) into GAL3-null, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-resistant human breast carcinoma cells promotes TRAIL-induced apoptotic cell death by stimulating the phosphorylation/inactivation of the pro-apoptotic molecule Bad resulting in the inhibition of mitochondrial depolarization and the release of cytochrome c. Exposure of the transfectant cells to TRAIL leads to the recruitment of the initiator capase-8 followed by activation of the effector caspase-9, independent of cytochrome c, and subsequently the processing of the executioner caspase-3. P-GAL3 and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) were coordinately expressed, with concomitant dephosphorylation of Akt in TRAIL-sensitive cells. In contrast, overexpression of phospho-mutant GAL3 (incapable of phosphorylation) failed to elicit similar responses. Depletion of PTEN using small interference RNAs reinstated Akt phosphorylation and conferred TRAIL resistance. In addition phosphatidylinositol 3-kinase inhibitors rendered the phospho-mutant GAL3-resistant cells sensitive to TRAIL. These findings suggest a pivotal role for P-GAL3 in promoting TRAIL sensitivity through activation of a nonclassic apoptotic pathway and identify P-GAL3 as a novel regulator of PTEN.
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Affiliation(s)
- Nachman Mazurek
- Department of Gastrointestinal Medicine and Nutrition, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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