1
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de Caestecker C, Macara IG. A size filter at the Golgi regulates apical membrane protein sorting. Nat Cell Biol 2024:10.1038/s41556-024-01500-0. [PMID: 39237743 DOI: 10.1038/s41556-024-01500-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/12/2024] [Indexed: 09/07/2024]
Abstract
Despite decades of research, apical sorting of epithelial membrane proteins remains incompletely understood. We noted that apical cytoplasmic domains are smaller than those of basolateral proteins; however, the reason for this discrepancy is unknown. Here we used a synthetic biology approach to investigate whether a size barrier at the Golgi apparatus might hinder apical sorting of proteins with large cytoplasmic tails. We focused on Crb3, Ace2 and Muc1 as representative apical proteins with short cytoplasmic tails. By incorporating a streptavidin-binding peptide, these proteins can be trapped in the endoplasmic reticulum until addition of biotin, which triggers synchronous release to the Golgi and subsequent transport to the apical cortex. Strikingly, increasing the size of their cytoplasmic domains caused partial mislocalization to the basolateral cortex and significantly delayed Golgi departure. Moreover, N-glycosylation of 'large' Crb3 was delayed, and 'small' Crb3 segregated into spatially distinct Golgi regions. Biologically, Crb3 forms a complex through its cytoplasmic tail with the Pals1 protein, which could also delay departure, but although associated at the endoplasmic reticulum and Golgi, Pals1 disassociated before Crb3 departure. Notably, a non-dissociable mutant Pals1 hampered the exit of Crb3. We conclude that, unexpectedly, a size filter at the Golgi facilitates apical sorting of proteins with small cytoplasmic domains and that timely release of Pals1, to reduce cytoplasmic domain size, is essential for normal Crb3 sorting.
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Affiliation(s)
- Christian de Caestecker
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Ian G Macara
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.
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2
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Radziejewska I. Tumor-associated carbohydrate antigens of MUC1 - Implication in cancer development. Biomed Pharmacother 2024; 174:116619. [PMID: 38643541 DOI: 10.1016/j.biopha.2024.116619] [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: 01/29/2024] [Revised: 04/12/2024] [Accepted: 04/17/2024] [Indexed: 04/23/2024] Open
Abstract
Glycosylation of cancerous epithelial MUC1 protein is specifically altered in comparison to that which is presented by healthy cells. One of such changes is appearing tumor-associated carbohydrate antigens (TACAs) which are rare in normal tissues and are highly correlated with poor clinical outcomes and cancer progression. This review summarizes and describes the role of Tn, T antigens, their sialylated forms as well as fucosylated Lewis epitopes in different aspects of tumor development, progression, and metastasis. Finally, applications of MUC1 glycan epitopes as potential targets for therapeutic strategy of cancers are notified. One of the novelties of this review is presentation of TACAs as inherently connected with MUC1 mucin.
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Affiliation(s)
- Iwona Radziejewska
- Department of Medical Chemistry, Medical University of Białystok, ul. Mickiewicza 2, Białystok 15-222, Poland.
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3
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Wang J, Platz-Baudin E, Noetzel E, Offenhäusser A, Maybeck V. Expressing Optogenetic Actuators Fused to N-terminal Mucin Motifs Delivers Targets to Specific Subcellular Compartments in Polarized Cells. Adv Biol (Weinh) 2024; 8:e2300428. [PMID: 38015104 DOI: 10.1002/adbi.202300428] [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: 08/15/2023] [Revised: 10/31/2023] [Indexed: 11/29/2023]
Abstract
Optogenetics is a powerful approach in neuroscience research. However, other tissues of the body may benefit from controlled ion currents and neuroscience may benefit from more precise optogenetic expression. The present work constructs three subcellularly-targeted optogenetic actuators based on the channelrhodopsin ChR2-XXL, utilizing 5, 10, or 15 tandem repeats (TR) from mucin as N-terminal targeting motifs and evaluates expression in several polarized and non-polarized cell types. The modified channelrhodopsin maintains its electrophysiological properties, which can be used to produce continuous membrane depolarization, despite the expected size of the repeats. This work then shows that these actuators are subcellularly localized in polarized cells. In polarized epithelial cells, all three actuators localize to just the lateral membrane. The TR-tagged constructs also express subcellularly in cortical neurons, where TR5-ChR2XXL and TR10-ChR2XXL mainly target the somatodendrites. Moreover, the transfection efficiencies are shown to be dependent on cell type and tandem repeat length. Overall, this work verifies that the targeting motifs from epithelial cells can be used to localize optogenetic actuators in both epithelia and neurons, opening epithelia processes to optogenetic manipulation and providing new possibilities to target optogenetic tools.
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Affiliation(s)
- Jiali Wang
- Institute of Biological Information Processing IBI-3, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52062, Aachen, Germany
| | - Eric Platz-Baudin
- Institute of Biological Information Processing IBI-2, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Erik Noetzel
- Institute of Biological Information Processing IBI-2, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Andreas Offenhäusser
- Institute of Biological Information Processing IBI-3, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52062, Aachen, Germany
| | - Vanessa Maybeck
- Institute of Biological Information Processing IBI-3, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
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4
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de Caestecker C, Macara IG. A Size Filter Regulates Apical Protein Sorting. RESEARCH SQUARE 2023:rs.3.rs-3210598. [PMID: 37577471 PMCID: PMC10418535 DOI: 10.21203/rs.3.rs-3210598/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Despite decades of research, apical sorting of epithelial membrane proteins remains incompletely understood. We noted that apical cytoplasmic domains are smaller than those of basolateral proteins; however, the reason for this discrepancy is unknown. We investigated whether a size barrier at the trans-Golgi network (TGN) might hinder apical sorting of proteins with large cytoplasmic tails. We focused on Crb3 and Ace2 as representative apical proteins with short cytoplasmic tails. By incorporating a streptavidin-binding peptide, these proteins can be trapped in the endoplasmic reticulum (ER) until addition of biotin, which triggers synchronous release to the Golgi and subsequent transport to the apical cortex. Strikingly, departure from the Golgi could be significantly delayed simply by increasing cytoplasmic bulk. Moreover, large and small Crb3 segregated into spatially distinct Golgi regions as detected by super resolution imaging. Biologically, Crb3 forms a complex through its cytoplasmic tail with the Pals1 protein, which could also delay departure, but although associated at the ER and Golgi, we found that Pals1 disassociates prior to Crb3 departure. Notably, a non-dissociable mutant Pals1 hampers the exit of Crb3. We conclude that an unexpected mechanism involving a size filter at the TGN facilitates apical sorting of proteins with small cytoplasmic domains and that timely release of Pals1, to reduce cytoplasmic domain size, is essential for the normal kinetics of Crb3 sorting.
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Affiliation(s)
- Christian de Caestecker
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine; Nashville TN 37205, U.S
| | - Ian G. Macara
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine; Nashville TN 37205, U.S
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5
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Semba R, Horimoto Y, Sakata-Matsuzawa M, Ishizuka Y, Denda-Nagai K, Fujihira H, Noji M, Onagi H, Ichida M, Miura H, Watanabe J, Saito M, Saito T, Arakawa A, Irimura T. Possible correlation of apical localization of MUC1 glycoprotein with luminal A-like status of breast cancer. Sci Rep 2023; 13:5281. [PMID: 37002293 PMCID: PMC10066179 DOI: 10.1038/s41598-023-32579-4] [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: 09/21/2022] [Accepted: 03/29/2023] [Indexed: 04/03/2023] Open
Abstract
Adjuvant chemotherapy has played a major role in the treatment of hormone receptor-positive breast cancer for many years. To better determine which patient subsets need adjuvant chemotherapy, various gene expression analyses have been developed, but cost-effective tools to identify such patients remain elusive. In the present report, we retrospectively investigated immunohistochemical expression and subcellular localization of MUC1 in primary tumors and examined their relationship to tumor malignancy, chemotherapy effect and patient outcomes. We retrospectively examined three patient cohorts with hormone receptor-positive/human epidermal growth factor receptor 2-negative invasive breast cancer: 51 patients who underwent 21-gene expression analysis (multi-gene assay-cohort), 96 patients who received neoadjuvant chemotherapy (neoadjuvant chemotherapy-cohort), and 609 patients whose tumor tissue was used in tissue-microarrays (tissue-microarray-cohort). The immunohistochemical staining pattern of the anti-MUC1 monoclonal antibody, Ma695, was examined in cancer tissues, and subcellular localization was determined as apical, cytoplasmic or negative. In the multi-gene assay-cohort, tumors with apical patterns had the lowest recurrence scores, reflecting lower tumor malignancy, and were significantly lower than MUC1-negative tumors (P = 0.038). In the neoadjuvant chemotherapy-cohort, there was no correlation between MUC1 staining patterns and effects of chemotherapy. Finally, in the tissue-microarray-cohort, we found that patients with apical MUC1 staining patterns had significantly longer disease-free-survival and overall survival than other patterns (P = 0.020 and 0.039, respectively). Our data suggest that an apical MUC1 staining pattern indicates luminal A-likeness. Assessment of the subcellular localization of MUC1 glycoprotein may be useful for identifying patients who can avoid adjuvant chemotherapy.
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Affiliation(s)
- Ryoko Semba
- Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, 113-0033, Japan
| | - Yoshiya Horimoto
- Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, 113-0033, Japan.
- Department of Human Pathology, Juntendo University Faculty of Medicine, Tokyo, Japan.
| | - Madoka Sakata-Matsuzawa
- Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, 113-0033, Japan
| | - Yumiko Ishizuka
- Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, 113-0033, Japan
| | - Kaori Denda-Nagai
- Intractable Disease Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Haruhiko Fujihira
- Division of Glycobiologics, Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, Japan
- Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, RIKEN, Wako, Japan
| | - Miki Noji
- Division of Glycobiologics, Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Hiroko Onagi
- Department of Human Pathology, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Miyu Ichida
- Department of Human Pathology, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Hiroyoshi Miura
- Department of Surgery, Koshigaya Municipal Hospital, Saitama, Japan
| | - Junichiro Watanabe
- Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, 113-0033, Japan
| | - Mitsue Saito
- Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, 113-0033, Japan
| | - Tsuyoshi Saito
- Department of Human Pathology, Juntendo University Faculty of Medicine, Tokyo, Japan
- Intractable Disease Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Atsushi Arakawa
- Department of Human Pathology, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Tatsuro Irimura
- Division of Glycobiologics, Department of Breast Oncology, Juntendo University Faculty of Medicine, Tokyo, Japan
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6
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Al-Bataineh MM, Kinlough CL, Marciszyn A, Lam T, Ye L, Kidd K, Maggiore JC, Poland PA, Kmoch S, Bleyer A, Bain DJ, Montalbetti N, Kleyman TR, Hughey RP, Ray EC. Influence of glycoprotein MUC1 on trafficking of the Ca 2+-selective ion channels, TRPV5 and TRPV6, and on in vivo calcium homeostasis. J Biol Chem 2023; 299:102925. [PMID: 36682497 PMCID: PMC9996365 DOI: 10.1016/j.jbc.2023.102925] [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: 09/02/2022] [Revised: 01/09/2023] [Accepted: 01/12/2023] [Indexed: 01/22/2023] Open
Abstract
Polymorphism of the gene encoding mucin 1 (MUC1) is associated with skeletal and dental phenotypes in human genomic studies. Animals lacking MUC1 exhibit mild reduction in bone density. These phenotypes could be a consequence of modulation of bodily Ca homeostasis by MUC1, as suggested by the previous observation that MUC1 enhances cell surface expression of the Ca2+-selective channel, TRPV5, in cultured unpolarized cells. Using biotinylation of cell surface proteins, we asked whether MUC1 influences endocytosis of TRPV5 and another Ca2+-selective TRP channel, TRPV6, in cultured polarized epithelial cells. Our results indicate that MUC1 reduces endocytosis of both channels, enhancing cell surface expression. Further, we found that mice lacking MUC1 lose apical localization of TRPV5 and TRPV6 in the renal tubular and duodenal epithelium. Females, but not males, lacking MUC1 exhibit reduced blood Ca2+. However, mice lacking MUC1 exhibited no differences in basal urinary Ca excretion or Ca retention in response to PTH receptor signaling, suggesting compensation by transport mechanisms independent of TRPV5 and TRPV6. Finally, humans with autosomal dominant tubulointerstitial kidney disease due to frame-shift mutation of MUC1 (ADTKD-MUC1) exhibit reduced plasma Ca concentrations compared to control individuals with mutations in the gene encoding uromodulin (ADTKD-UMOD), consistent with MUC1 haploinsufficiency causing reduced bodily Ca2+. In summary, our results provide further insight into the role of MUC1 in Ca2+-selective TRP channel endocytosis and the overall effects on Ca concentrations.
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Affiliation(s)
- Mohammad M Al-Bataineh
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Carol L Kinlough
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Allison Marciszyn
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Tracey Lam
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Lorena Ye
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kendrah Kidd
- Section on Nephrology, Department of Medicine, Wake Forest University, Winston-Salem, North Carolina, USA; Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Joseph C Maggiore
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Paul A Poland
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Stanislav Kmoch
- Section on Nephrology, Department of Medicine, Wake Forest University, Winston-Salem, North Carolina, USA; Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Anthony Bleyer
- Section on Nephrology, Department of Medicine, Wake Forest University, Winston-Salem, North Carolina, USA; Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Daniel J Bain
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nicolas Montalbetti
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Thomas R Kleyman
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rebecca P Hughey
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
| | - Evan C Ray
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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7
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Wang CY, Bergström E, Southgate J, Thomas-Oates J. Surface Shave: Revealing the Apical-Restricted Uroglycome. J Proteome Res 2022; 21:360-374. [PMID: 34985888 DOI: 10.1021/acs.jproteome.1c00714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study aimed to investigate the highly differentiated urothelial apical surface glycome. The functions of the mammalian urothelium, lining the majority of the urinary tract and providing a barrier against toxins in urine, are dependent on the correct differentiation of urothelial cells, relying on protein expression, modification, and complex assembly to regulate the formation of multiple differentiated cell layers. Protein glycosylation, a poorly studied aspect of urothelial differentiation, contributes to the apical glycome and is implicated in the development of urothelial diseases. To enable surface glycome characterization, we developed a method to collect tissue apical surface N- and O-glycans. A simple, novel device using basic laboratory supplies was developed for enzymatic shaving of the luminal bladder urothelial surface, with subsequent release and mass spectrometric analysis of apical surface O- and N-glycans, the first normal mammalian urothelial N-glycome to be defined. Trypsinization of superficial glycoproteins was tracked using immunolabeling of the apically expressed uroplakin 3a protein to optimize enzymatic release, without compromising the integrity of the superficial urothelial layer. The approach developed for releasing apical tissue surface glycans allowed for comparison with the N-glycome of the total porcine bladder urothelial cells and thus identification of apical surface glycans as candidates implicated in the urothelial barrier function. Data are available in MassIve: MSV000087851.
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Affiliation(s)
- Chung-Yao Wang
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
| | - Edmund Bergström
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.,Centre of Excellence in Mass Spectrometry, University of York, Heslington, York YO10 5DD, U.K
| | - Jennifer Southgate
- Jack Birch Unit, Department of Biology, York Biomedical Research Institute; University of York, Heslington, York YO10 5DD, U.K
| | - Jane Thomas-Oates
- Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.,Centre of Excellence in Mass Spectrometry, University of York, Heslington, York YO10 5DD, U.K
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8
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Poland PA, Kinlough CL, Hughey RP. Cloning, Expression, and Purification of Galectins for In Vitro Studies. Methods Mol Biol 2022; 2442:41-54. [PMID: 35320518 DOI: 10.1007/978-1-0716-2055-7_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Galectins are best known for their ability to bind glycoconjugates containing β-galactose, but classification of these small proteins within the galectin family is also defined by amino acid homology within structural domains and exon/intron junctions within genes. As galectins are expressed by organisms as diverse as some fungi, C. elegans, fish, birds and mammals, and biological activities attributed to galectins are equally diverse, it becomes essential to identify, clone, and characterize galectins from many sources. Glutathione S-transferase (GST) fused to the amino-terminus of galectin cDNAs has proven to be especially useful for the preparation of recombinant galectins in bacteria for use on glycan arrays, in experiments with cultured or isolated cells, and in pull-down assays with immunopurified glycoproteins. Many galectins are stabilized by reducing reagents, such that binding and elution of GST-galectins from glutathione-conjugated Sepharose with excess glutathione is both efficient and innocuous. The ability to bind and elute GST-galectins from lactose-conjugated Sepharose with excess lactose provides a relatively easy means to insure that galectins are competent for glycoconjugate binding prior to experimentation. This chapter focuses primarily on the varied approaches to use GST-galectin binding to glutathione- and lactose-conjugated Sepharose to purify recombinant galectins and then develop effective experimental protocols to characterize the specificity, interactions and function of galectins cloned from any source. We provide one example where a pull-down assay with all the GST-tagged canine galectins reveals that the C-terminal carbohydrate recognition domain of galectin-9 (Gal-9C) specifically recognizes the glycan-dependent apical targeting signal from the glycoprotein MUC1.
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Affiliation(s)
- Paul A Poland
- Renal-Electrolyte Division, Department of Medicine, Laboratory of Epithelial Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Carol L Kinlough
- Renal-Electrolyte Division, Department of Medicine, Laboratory of Epithelial Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rebecca P Hughey
- Renal-Electrolyte Division, Department of Medicine, Laboratory of Epithelial Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.
- University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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9
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Zeke A, Dobson L, Szekeres LI, Langó T, Tusnády GE. PolarProtDb: A Database of Transmembrane and Secreted Proteins showing Apical-Basal Polarity. J Mol Biol 2020; 433:166705. [PMID: 33186585 DOI: 10.1016/j.jmb.2020.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 12/13/2022]
Abstract
Most cells in multicellular organisms are somehow asymmetric, polarized: maintaining separate membrane domains. Typical examples are the epithelial cells (apical-basal polarization), neurons (dendritic-axonal domains), or migratory cells (with a leading and a trailing edge). Here we present the most comprehensive database containing experimentally verified mammalian proteins that display polarized sorting or secretion, focusing on epithelial polarity. In addition to the source cells or tissues, homology-based inferences and transmembrane topology (if applicable) are all provided. PolarProtDb also offers a detailed interface displaying all information that may be relevant for trafficking: including post-translational modifications (glycosylations and phosphorylations), known or predicted short linear motifs conserved across orthologs, as well as potential interaction partners. Data on polarized sorting has so far been scattered across myriads of publications, hence difficult to access. This information can help researchers in several areas, such as scanning for potential entry points of viral agents like COVID-19. PolarProtDb shall be a useful resource to design future experiments as well as for comparative analyses. The database is available at http://polarprotdb.enzim.hu.
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Affiliation(s)
- András Zeke
- Membrane Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary
| | - László Dobson
- Membrane Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Levente István Szekeres
- Membrane Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary
| | - Tamás Langó
- Membrane Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary
| | - Gábor E Tusnády
- Membrane Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok körútja 2, H-1117 Budapest, Hungary.
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10
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Abstract
Membrane mucins cover most mucosal surfaces throughout the human body. The intestine harbors complex population of microorganisms (the microbiota) and numerous exogenous molecules that can harm the epithelium. In the colon, where the microbial burden is high, a mucus barrier forms the first line of defense by keeping bacteria away from the epithelial cells. In the small intestine where the mucus layer is less organized, microbes are kept at bay by peristalsis and antimicrobial peptides. Additionally, a dense glycocalyx consisting of extended and heavily glycosylated membrane mucins covers the surface of enterocytes. Whereas many aspects of mucosal barriers are being discovered, the function of membrane mucins remains a largely overlooked topic, mainly because we lack the necessary reagents and experimental animal models to investigate these large glycoproteins. In this Cell Science at a Glance article and accompanying poster, we highlight central concepts of membrane mucin biology and the role of membrane mucins as integral components of intestinal mucosal barriers. We also present the current consensus concerning the role of membrane mucins in host-microbe interactions. Moreover, we discuss how regulatory circuits that govern membrane mucins in the healthy gut display strong overlap with pathways that are perturbed during chronic inflammation. Finally, we review how dysregulation of intestinal membrane mucins may contribute to human diseases, such as inflammation and cancer.
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Affiliation(s)
- Thaher Pelaseyed
- Dept. Medical Biochemistry, University of Gothenburg, Box 440, 40530 Gothenburg, Sweden
| | - Gunnar C Hansson
- Dept. Medical Biochemistry, University of Gothenburg, Box 440, 40530 Gothenburg, Sweden
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11
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Kvorjak M, Ahmed Y, Miller ML, Sriram R, Coronnello C, Hashash JG, Hartman DJ, Telmer CA, Miskov-Zivanov N, Finn OJ, Cascio S. Cross-talk between Colon Cells and Macrophages Increases ST6GALNAC1 and MUC1-sTn Expression in Ulcerative Colitis and Colitis-Associated Colon Cancer. Cancer Immunol Res 2019; 8:167-178. [PMID: 31831633 DOI: 10.1158/2326-6066.cir-19-0514] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/03/2019] [Accepted: 12/03/2019] [Indexed: 12/21/2022]
Abstract
Patients with ulcerative colitis have an increased risk of developing colitis-associated colon cancer (CACC). Changes in glycosylation of the oncoprotein MUC1 commonly occur in chronic inflammation, including ulcerative colitis, and this abnormally glycosylated MUC1 promotes cancer development and progression. It is not known what causes changes in glycosylation of MUC1. Gene expression profiling of myeloid cells in inflamed and malignant colon tissues showed increased expression levels of inflammatory macrophage-associated cytokines compared with normal tissues. We analyzed the involvement of macrophage-associated cytokines in the induction of aberrant MUC1 glycoforms. A coculture system was used to examine the effects of M1 and M2 macrophages on glycosylation-related enzymes in colon cancer cells. M2-like macrophages induced the expression of the glycosyltransferase ST6GALNAC1, an enzyme that adds sialic acid to O-linked GalNAc residues, promoting the formation of tumor-associated sialyl-Tn (sTn) O-glycans. Immunostaining of ulcerative colitis and CACC tissue samples confirmed the elevated number of M2-like macrophages as well as high expression of ST6GALNAC1 and the altered MUC1-sTn glycoform on colon cells. Cytokine arrays and blocking antibody experiments indicated that the macrophage-dependent ST6GALNAC1 activation was mediated by IL13 and CCL17. We demonstrated that IL13 promoted phosphorylation of STAT6 to activate transcription of ST6GALNAC1. A computational model of signaling pathways was assembled and used to test IL13 inhibition as a possible therapy. Our findings revealed a novel cellular cross-talk between colon cells and macrophages within the inflamed and malignant colon that contributes to the pathogenesis of ulcerative colitis and CACC.See related Spotlight on p. 160.
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Affiliation(s)
- Michael Kvorjak
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Yasmine Ahmed
- Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Michelle L Miller
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Raahul Sriram
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | - Jana G Hashash
- Department of Gastroenterology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Douglas J Hartman
- Department of Pathology University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Cheryl A Telmer
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Natasa Miskov-Zivanov
- Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Olivera J Finn
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Sandra Cascio
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania. .,Fondazione Ri.Med, Palermo, Italy.,Department of Obstetrics, Gynecology, & Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
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12
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Fois CAM, Le TYL, Schindeler A, Naficy S, McClure DD, Read MN, Valtchev P, Khademhosseini A, Dehghani F. Models of the Gut for Analyzing the Impact of Food and Drugs. Adv Healthc Mater 2019; 8:e1900968. [PMID: 31592579 DOI: 10.1002/adhm.201900968] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/30/2019] [Indexed: 12/16/2022]
Abstract
Models of the human gastrointestinal tract (GIT) can be powerful tools for examining the biological interactions of food products and pharmaceuticals. This can be done under normal healthy conditions or using models of disease-many of which have no curative therapy. This report outlines the field of gastrointestinal modeling, with a particular focus on the intestine. Traditional in vivo animal models are compared to a range of in vitro models. In vitro systems are elaborated over time, recently culminating with microfluidic intestines-on-chips (IsOC) and 3D bioengineered models. Macroscale models are also reviewed for their important contribution in the microbiota studies. Lastly, it is discussed how in silico approaches may have utility in predicting and interpreting experimental data. The various advantages and limitations of the different systems are contrasted. It is posited that only through complementary use of these models will salient research questions be able to be addressed.
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Affiliation(s)
- Chiara Anna Maria Fois
- School of Chemical and Biomolecular Engineering Centre for Advanced Food Enginomics University of Sydney Sydney NSW 2006 Australia
| | - Thi Yen Loan Le
- School of Chemical and Biomolecular Engineering Centre for Advanced Food Enginomics University of Sydney Sydney NSW 2006 Australia
| | - Aaron Schindeler
- School of Chemical and Biomolecular Engineering Centre for Advanced Food Enginomics University of Sydney Sydney NSW 2006 Australia
| | - Sina Naficy
- School of Chemical and Biomolecular Engineering Centre for Advanced Food Enginomics University of Sydney Sydney NSW 2006 Australia
| | - Dale David McClure
- School of Chemical and Biomolecular Engineering Centre for Advanced Food Enginomics University of Sydney Sydney NSW 2006 Australia
| | - Mark Norman Read
- School of Chemical and Biomolecular Engineering Centre for Advanced Food Enginomics University of Sydney Sydney NSW 2006 Australia
| | - Peter Valtchev
- School of Chemical and Biomolecular Engineering Centre for Advanced Food Enginomics University of Sydney Sydney NSW 2006 Australia
| | - Ali Khademhosseini
- Department of Chemical and Biomolecular Engineering Department of Bioengineering Department of Radiology California NanoSystems Institute (CNSI) University of California Los Angeles CA 90095 USA
| | - Fariba Dehghani
- School of Chemical and Biomolecular Engineering Centre for Advanced Food Enginomics University of Sydney Sydney NSW 2006 Australia
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13
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Zhou X, Kinlough CL, Hughey RP, Jin M, Inoue H, Etling E, Modena BD, Kaminski N, Bleecker ER, Meyers DA, Jarjour NN, Trudeau JB, Holguin F, Ray A, Wenzel SE. Sialylation of MUC4β N-glycans by ST6GAL1 orchestrates human airway epithelial cell differentiation associated with type-2 inflammation. JCI Insight 2019; 4:122475. [PMID: 30730306 DOI: 10.1172/jci.insight.122475] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 01/29/2019] [Indexed: 12/28/2022] Open
Abstract
Although type-2-induced (T2-induced) epithelial dysfunction is likely to profoundly alter epithelial differentiation and repair in asthma, the mechanisms for these effects are poorly understood. A role for specific mucins, heavily N-glycosylated epithelial glycoproteins, in orchestrating epithelial cell fate in response to T2 stimuli has not previously been investigated. Levels of a sialylated MUC4β isoform were found to be increased in airway specimens from asthmatic patients in association with T2 inflammation. We hypothesized that IL-13 would increase sialylation of MUC4β, thereby altering its function and that the β-galactoside α-2,6-sialyltransferase 1 (ST6GAL1) would regulate the sialylation. Using human biologic specimens and cultured primary human airway epithelial cells (HAECs),we demonstrated that IL-13 increases ST6GAL1-mediated sialylation of MUC4β and that both were increased in asthma, particularly in sputum supernatant and/or fresh isolated HAECs with elevated T2 biomarkers. ST6GAL1-induced sialylation of MUC4β altered its lectin binding and secretion. Both ST6GAL1 and MUC4β inhibited epithelial cell proliferation while promoting goblet cell differentiation. These in vivo and in vitro data provide strong evidence for a critical role for ST6GAL1-induced sialylation of MUC4β in epithelial dysfunction associated with T2-high asthma, thereby identifying specific sialylation pathways as potential targets in asthma.
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Affiliation(s)
- Xiuxia Zhou
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh Asthma Institute at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.,Department of Environmental & Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Carol L Kinlough
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rebecca P Hughey
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mingzhu Jin
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh Asthma Institute at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Hideki Inoue
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh Asthma Institute at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.,Division of Pulmonary and Allergy Medicine, Department of Medicine, Showa University School of Medicine, Tokyo, Japan
| | - Emily Etling
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh Asthma Institute at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Brian D Modena
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh Asthma Institute at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.,Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Naftali Kaminski
- Section of Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | | | - Deborah A Meyers
- Department of Medicine, University of Arizona, Tucson, Arizona, USA
| | - Nizar N Jarjour
- Division of Allergy, Pulmonary, and Critical Care Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - John B Trudeau
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh Asthma Institute at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.,Department of Environmental & Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Fernando Holguin
- Division of Pulmonary and Critical Care Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA
| | - Anuradha Ray
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh Asthma Institute at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.,Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sally E Wenzel
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh Asthma Institute at University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.,Department of Environmental & Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
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14
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Abstract
PURPOSE OF REVIEW Recent studies in the kidney have revealed that the well characterized tumor antigen mucin 1 (MUC1/Muc1) also has numerous functions in the normal and injured kidney. RECENT FINDINGS Mucin 1 is a transmembrane mucin with a robust glycan-dependent apical targeting signal and efficient recycling from endosomes. It was recently reported that the TRPV5 calcium channel is stabilized on the cell surface by galectin-dependent cross-linking to mucin 1, providing a novel mechanism for regulation of ion channels and normal electrolyte balance.Our recent studies in mice show that Muc 1 is induced after ischemia, stabilizing hypoxia-inducible factor 1 (HIF-1)α and β-catenin levels, and transactivating the HIF-1 and β-catenin protective pathways. However, prolonged induction of either pathway in the injured kidney can proceed from apparent full recovery to chronic kidney disease. A very recent report indicates that aberrant activation of mucin 1 signaling after ischemic injury in mice and humans is associated with development of chronic kidney disease and fibrosis. A frameshift mutation in MUC1 was recently identified as the genetic lesion causing medullary cystic kidney disease type 1, now appropriately renamed MUC1 Kidney Disease. SUMMARY Studies of mucin 1 in the kidney now reveal significant functions for the extracellular mucin-like domain and signaling through the cytoplasmic tail.
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15
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Yamamoto S, Kaimori JY, Yoshimura T, Namba T, Imai A, Kobayashi K, Imamura R, Ichimaru N, Kato K, Nakaya A, Takahara S, Isaka Y. Analysis of an ADTKD family with a novel frameshift mutation in MUC1 reveals characteristic features of mutant MUC1 protein. Nephrol Dial Transplant 2017; 32:2010-2017. [DOI: 10.1093/ndt/gfx083] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 04/05/2017] [Indexed: 01/25/2023] Open
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16
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Cascio S, Finn OJ. Intra- and Extra-Cellular Events Related to Altered Glycosylation of MUC1 Promote Chronic Inflammation, Tumor Progression, Invasion, and Metastasis. Biomolecules 2016; 6:biom6040039. [PMID: 27754373 PMCID: PMC5197949 DOI: 10.3390/biom6040039] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/29/2016] [Accepted: 09/27/2016] [Indexed: 12/12/2022] Open
Abstract
Altered glycosylation of mucin 1 (MUC1) on tumor cells compared to normal epithelial cells was previously identified as an important antigenic modification recognized by the immune system in the process of tumor immunosurveillance. This tumor form of MUC1 is considered a viable target for cancer immunotherapy. The importance of altered MUC1 glycosylation extends also to its role as a promoter of chronic inflammatory conditions that lead to malignant transformation and cancer progression. We review here what is known about the role of specific cancer-associated glycans on MUC1 in protein-protein interactions and intracellular signaling in cancer cells and in their adhesion to each other and the tumor stroma. The tumor form of MUC1 also creates a different landscape of inflammatory cells in the tumor microenvironment by controlling the recruitment of inflammatory cells, establishing specific interactions with dendritic cells (DCs) and macrophages, and facilitating tumor escape from the immune system. Through multiple types of short glycans simultaneously present in tumors, MUC1 acquires multiple oncogenic properties that control tumor development, progression, and metastasis at different steps of the process of carcinogenesis.
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Affiliation(s)
- Sandra Cascio
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
- Fondazione Ri.Med, via Bandiera 11, Palermo 90133, Italy.
| | - Olivera J Finn
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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17
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Monhasery N, Moll J, Cuman C, Franke M, Lamertz L, Nitz R, Görg B, Häussinger D, Lokau J, Floss DM, Piekorz R, Dimitriadis E, Garbers C, Scheller J. Transcytosis of IL-11 and Apical Redirection of gp130 Is Mediated by IL-11α Receptor. Cell Rep 2016; 16:1067-1081. [PMID: 27425614 DOI: 10.1016/j.celrep.2016.06.062] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 04/08/2016] [Accepted: 06/14/2016] [Indexed: 12/12/2022] Open
Abstract
Interleukin (IL)-11 signaling is involved in various processes, including epithelial intestinal cell regeneration and embryo implantation. IL-11 signaling is initiated upon binding of IL-11 to IL-11R1 or IL-11R2, two IL-11α-receptor splice variants, and gp130. Here, we show that IL-11 signaling via IL-11R1/2:gp130 complexes occurs on both the apical and basolateral sides of polarized cells, whereas IL-6 signaling via IL-6R:gp130 complexes is restricted to the basolateral side. We show that basolaterally supplied IL-11 is transported and released to the apical extracellular space via transcytosis in an IL-11R1-dependent manner. By contrast, IL-6R and IL-11R2 do not promote transcytosis. In addition, we show that transcytosis of IL-11 is dependent on the intracellular domain of IL-11R1 and that synthetic transfer of the intracellular domain of IL-11R1 to IL-6R promotes transcytosis of IL-6. Our data define IL-11R as a cytokine receptor with transcytotic activity by which IL-11 and IL-6:soluble IL-6R complexes are transported across cellular barriers.
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Affiliation(s)
- Niloufar Monhasery
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Jens Moll
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Carly Cuman
- Centre for Reproductive Health, The Hudson Institute of Medical Research, Clayton, 3168 VIC, Australia; Department of Molecular and Translational Medicine, Monash University, Clayton, 3168 VIC, Australia
| | - Manuel Franke
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Larissa Lamertz
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Rebecca Nitz
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Boris Görg
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Dieter Häussinger
- Department of Molecular and Translational Medicine, Monash University, Clayton, 3168 VIC, Australia
| | - Juliane Lokau
- Institute of Biochemistry, Kiel University, Olshausenstrasse 40, 24098 Kiel, Germany
| | - Doreen M Floss
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Roland Piekorz
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Eva Dimitriadis
- Centre for Reproductive Health, The Hudson Institute of Medical Research, Clayton, 3168 VIC, Australia; Department of Molecular and Translational Medicine, Monash University, Clayton, 3168 VIC, Australia
| | - Christoph Garbers
- Institute of Biochemistry, Kiel University, Olshausenstrasse 40, 24098 Kiel, Germany
| | - Jürgen Scheller
- Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine University, 40225 Düsseldorf, Germany.
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18
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Treat AC, Wheeler DS, Stolz DB, Tsang M, Friedman PA, Romero G. The PDZ Protein Na+/H+ Exchanger Regulatory Factor-1 (NHERF1) Regulates Planar Cell Polarity and Motile Cilia Organization. PLoS One 2016; 11:e0153144. [PMID: 27055101 PMCID: PMC4824468 DOI: 10.1371/journal.pone.0153144] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/24/2016] [Indexed: 12/23/2022] Open
Abstract
Directional flow of the cerebrospinal fluid requires coordinated movement of the motile cilia of the ependymal epithelium that lines the cerebral ventricles. Here we report that mice lacking the Na+/H+ Exchanger Regulatory Factor 1 (NHERF1/Slc9a3r1, also known as EBP50) develop profound communicating hydrocephalus associated with fewer and disorganized ependymal cilia. Knockdown of NHERF1/slc9a3r1 in zebrafish embryos also causes severe hydrocephalus of the hindbrain and impaired ciliogenesis in the otic vesicle. Ultrastructural analysis did not reveal defects in the shape or organization of individual cilia. Similar phenotypes have been described in animals with deficiencies in Wnt signaling and the Planar Cell Polarity (PCP) pathway. We show that NHERF1 binds the PCP core genes Frizzled (Fzd) and Vangl. We further show that NHERF1 assembles a ternary complex with Fzd4 and Vangl2 and promotes translocation of Vangl2 to the plasma membrane, in particular to the apical surface of ependymal cells. Taken together, these results strongly support an important role for NHERF1 in the regulation of PCP signaling and the development of functional motile cilia.
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Affiliation(s)
- Anny Caceres Treat
- Laboratory for GPCR Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - David S Wheeler
- Laboratory for GPCR Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.,Medical Scientist Training Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Donna B Stolz
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Michael Tsang
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Peter A Friedman
- Laboratory for GPCR Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.,Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Guillermo Romero
- Laboratory for GPCR Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
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19
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Abstract
Mucins are a family of secreted and transmembrane glycoproteins characterized by a massive domain of dense O-glycosylation on serine and threonine residues. Mucins are intimately involved in immunity and cancer, yet elucidation of the biological roles of their glycodomains has been complicated by their massive size, domain polymorphisms, and variable glycosylation patterns. Here we developed a synthetic route to a library of compositionally defined, high-molecular weight, dual end-functionalized mucin glycodomain constructs via N-carboxyanhydride polymerization. These glycopolypeptides are the first synthetic analogs to our knowledge to feature the native α-GalNAc linkage to serine with molecular weights similar to native mucins, solving a nearly 50-year synthetic challenge. Physical characterization of the mimics revealed insights into the structure and properties of mucins. The synthetic glycodomains were end-functionalized with an optical probe and a tetrazine moiety, which allowed site-specific bioorthogonal conjugation to an engineered membrane protein on live mammalian cells. This strategy in protein engineering will open avenues to explore the biological roles of cell surface mucins.
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20
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Chugh S, Gnanapragassam VS, Jain M, Rachagani S, Ponnusamy MP, Batra SK. Pathobiological implications of mucin glycans in cancer: Sweet poison and novel targets. Biochim Biophys Acta Rev Cancer 2015; 1856:211-25. [PMID: 26318196 DOI: 10.1016/j.bbcan.2015.08.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 08/15/2015] [Accepted: 08/25/2015] [Indexed: 12/13/2022]
Abstract
Mucins are large glycoproteins expressed on the epithelia that provide a protective barrier against harsh insults from toxins and pathogenic microbes. These glycoproteins are classified primarily as being secreted and membrane-bound; both forms are involved in pathophysiological functions including inflammation and cancer. The high molecular weight of mucins is attributed to their large polypeptide backbone that is extensively covered by glycan moieties that modulate the function of mucins and, hence, play an important role in physiological functions. Deregulation of glycosylation machinery during malignant transformation results in altered mucin glycosylation. This review describes the functional implications and pathobiological significance of altered mucin glycosylation in cancer. Further, this review delineates various factors such as glycosyltransferases and tumor microenvironment that contribute to dysregulation of mucin glycosylation during cancer. Finally, this review discusses the scope of mucin glycan epitopes as potential diagnostic and therapeutic targets.
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Affiliation(s)
- Seema Chugh
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Vinayaga S Gnanapragassam
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Maneesh Jain
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA; Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Satyanarayana Rachagani
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Moorthy P Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA; Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA; Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA; Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA.
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21
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Abstract
Galectins, a family of β-galactoside binding proteins, do not possess a signalling sequence to enter the endoplasmic reticulum as a starting point for the classical secretory pathway. They use a so-called unconventional secretion mechanism for translocation across the plasma membrane and/or into the lumen of transport vesicles. The β-galactoside binding protein galectin-3 is highly expressed in a variety of epithelial cell lines. Polarized MDCK cells secrete this lectin predominantly into the apical medium. The lectin re-enters the cell by non-clathrin mediated endocytosis and passages through endosomal organelles. This internalized galectin-3 plays an important role in apical protein trafficking by directing the subcellular targeting of apical glycoproteins via oligomerization into high molecular weight clusters, a process that can be fine-tuned by changes in the environmental pH. Following release at the apical plasma membrane, the lectin can reenter the cell for another round of recycling and apical protein sorting. This review will briefly address galectin-3-functions in epithelia and focus on distinct phases in apical recycling of the lectin.
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Affiliation(s)
- Ellena Hönig
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Marburg, Germany
| | - Katharina Schneider
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Marburg, Germany
| | - Ralf Jacob
- Department of Cell Biology and Cell Pathology, Philipps University of Marburg, Marburg, Germany.
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22
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Abstract
Galectins are best known for their ability to bind glycoconjugates containing β-galactose, but classification of these small proteins within the galectin family is also defined by amino acid homology within structural domains and exon/intron junctions within genes. As galectins are expressed by organisms as diverse as some fungi, C. elegans, fish, birds, and mammals, and biological activities attributed to galectins are equally diverse, it becomes essential to identify, clone, and characterize galectins from many sources. Glutathione S-transferase (GST) fused to the amino-terminus of galectin cDNAs has proven to be especially useful for preparation of recombinant galectins in bacteria for use on glycan arrays, in experiments with cultured or isolated cells, and in pull-down assays with immunopurified glycoproteins. Many galectins are stabilized by reducing reagents, such that binding and elution of GST-galectins from glutathione-conjugated Sepharose with excess glutathione is both efficient and innocuous. The ability to bind and elute GST-galectins from lactose-conjugated Sepharose with excess lactose provides a relatively easy means to insure that galectins are competent for glycoconjugate binding prior to experimentation. This chapter focuses primarily on the varied approaches to use GST-galectin binding to glutathione- and lactose-conjugated Sepharose to purify recombinant galectins and then develop effective experimental protocols to characterize the specificity, interactions, and function of galectins cloned from any source. We provide one example where a pull-down assay with all the GST-tagged canine galectins reveals that the C-terminal carbohydrate recognition domain of galectin-9 (Gal-9C) specifically recognizes the glycan-dependent apical targeting signal from the glycoprotein MUC1.
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23
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Cascio S, Farkas AM, Hughey RP, Finn OJ. Altered glycosylation of MUC1 influences its association with CIN85: the role of this novel complex in cancer cell invasion and migration. Oncotarget 2014; 4:1686-97. [PMID: 24072600 PMCID: PMC3858555 DOI: 10.18632/oncotarget.1265] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
MUC1 is a transmembrane glycoprotein abnormally expressed in human adenocarcinomas. The extracellular domain of MUC1 contains a variable number of tandem repeats (VNTR) region that is extensively O-glycosylated in normal epithelia and underglycosylated in tumor cells. This change in posttranslational modification of MUC1 leads to changes in its normal functions including, we hypothesized, its interaction with other molecules. We identified CIN85, an adaptor protein involved in multiple cellular processes including signal transduction, cytoskeletal remodeling and cancer cell invasion, as one of several proteins that associate with MUC1 in tumor cells. CIN85 associates with both the cytosolic tail and the extracellular VNTR of MUC1. Co-immunoprecipitation and confocal immunofluorescence confirmed that MUC1 and CIN85 co-localize primarily at the plasma membrane but the complex can be found also in the cytosol and on the cytoskeleton. MUC1 and CIN85 are both over-expressed in early as well as advanced clinical stages of breast cancer and co-localize on invadopodia-like structures implicated in cell invasion. siRNA-mediated silencing of CIN85 and/or MUC1 revealed that MUC1 enhances CIN85-dependent breast cancer cell migration and invasion in vitro. However, ectopic expression of MUC1 enhances the motility induced by CIN85. When tested in vivo in a tumor metastasis model of B16 melanoma, mice injected with CIN85-depleted melanoma cells exhibited few or no lung metastasis and, similarly to the in vitro results, overexpression of MUC1 recovered the shCIN85-reduced metastatic process. Our findings implicate this newly identified CIN85/MUC1 complex associated with invadopodia-related molecules in promoting the invasive and metastatic potential of breast cancer.
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Affiliation(s)
- Sandra Cascio
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261
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24
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Karabasheva D, Cole NB, Donaldson JG. Roles for trafficking and O-linked glycosylation in the turnover of model cell surface proteins. J Biol Chem 2014; 289:19477-90. [PMID: 24891503 DOI: 10.1074/jbc.m114.564666] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteins targeted to the plasma membrane (PM) of cells are degraded at different rates. Sorting motifs contained within the cytoplasmic domains of transmembrane proteins, post-translational modifications (e.g. ubiquitination), and assembly into multiprotein or protein-lipid complexes all may affect the efficiency of endocytosis and recycling and influence the delivery to degradative compartments. Using the SNAP-tag labeling system, we examined the turnover of a model PM protein, the α chain of the interleukin-2 receptor (Tac). The surface lifetimes of SNAP-Tac fusions were influenced by their mode of entry into cells (clathrin-dependent versus clathrin-independent), their orientation in the PM (transmembrane versus glycosylphosphatidylinositol-anchored), and ubiquitination in their cytosolic domains. In addition, shedding of SNAP-Tac into the medium was greatly influenced by its O-linked glycosylation status. For a number of PM proteins, delivery to lysosomes and ectodomain shedding represent distinct parallel mechanisms to determine protein half-life.
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Affiliation(s)
- Darya Karabasheva
- From the Cell Biology and Physiology Center, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Nelson B Cole
- From the Cell Biology and Physiology Center, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Julie G Donaldson
- From the Cell Biology and Physiology Center, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
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25
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Persi E, Horn D. Systematic analysis of compositional order of proteins reveals new characteristics of biological functions and a universal correlate of macroevolution. PLoS Comput Biol 2013; 9:e1003346. [PMID: 24278003 PMCID: PMC3836704 DOI: 10.1371/journal.pcbi.1003346] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 10/03/2013] [Indexed: 01/01/2023] Open
Abstract
We present a novel analysis of compositional order (CO) based on the occurrence of Frequent amino-acid Triplets (FTs) that appear much more than random in protein sequences. The method captures all types of proteomic compositional order including single amino-acid runs, tandem repeats, periodic structure of motifs and otherwise low complexity amino-acid regions. We introduce new order measures, distinguishing between ‘regularity’, ‘periodicity’ and ‘vocabulary’, to quantify these phenomena and to facilitate the identification of evolutionary effects. Detailed analysis of representative species across the tree-of-life demonstrates that CO proteins exhibit numerous functional enrichments, including a wide repertoire of particular patterns of dependencies on regularity and periodicity. Comparison between human and mouse proteomes further reveals the interplay of CO with evolutionary trends, such as faster substitution rate in mouse leading to decrease of periodicity, while innovation along the human lineage leads to larger regularity. Large-scale analysis of 94 proteomes leads to systematic ordering of all major taxonomic groups according to FT-vocabulary size. This is measured by the count of Different Frequent Triplets (DFT) in proteomes. The latter provides a clear hierarchical delineation of vertebrates, invertebrates, plants, fungi and prokaryotes, with thermophiles showing the lowest level of FT-vocabulary. Among eukaryotes, this ordering correlates with phylogenetic proximity. Interestingly, in all kingdoms CO accumulation in the proteome has universal characteristics. We suggest that CO is a genomic-information correlate of both macroevolution and various protein functions. The results indicate a mechanism of genomic ‘innovation’ at the peptide level, involved in protein elongation, shaped in a universal manner by mutational and selective forces. Variations in compositionally ordered (CO) sections of proteins, such as amino acid runs, tandem repeats and low complexity regions, are often considered as a third type of genomic variation along with SNP and CNV. At the microevolutionary scale, they are involved in the rapid evolution of numerous biological functions and the development of novel phenotypic complex traits, including disease in human, in particular neurodegeneration and cancer. At the macroevolutionary scale, the best discriminating proteomic factor between super-kingdoms is the prevalence of CO proteins in eukaryotes. The analysis of CO structures has so far been quite eclectic. Here we introduce a novel unifying methodology, accounting for all types of low-complexity regions and repetitive phenomena, including the existence of large periodic structures in protein sequences. We define new CO measures providing insights into the correlation of CO with protein function and with evolution. In particular, a large-scale analysis of 94 proteomes shows that the CO vocabulary of frequently appearing amino acid triplets serves as a measure of taxonomic ordering separating major clades from each other. It unravels a missing genomic correlate of macroevolution and serves as a novel phylogenetic tool. This suggests that major CO generation occurs during the creation of a completely new species, i.e. during macroevolutionary events.
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Affiliation(s)
- Erez Persi
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
| | - David Horn
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
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Gerken TA, Revoredo L, Thome JJC, Tabak LA, Vester-Christensen MB, Clausen H, Gahlay GK, Jarvis DL, Johnson RW, Moniz HA, Moremen K. The lectin domain of the polypeptide GalNAc transferase family of glycosyltransferases (ppGalNAc Ts) acts as a switch directing glycopeptide substrate glycosylation in an N- or C-terminal direction, further controlling mucin type O-glycosylation. J Biol Chem 2013; 288:19900-14. [PMID: 23689369 PMCID: PMC3707691 DOI: 10.1074/jbc.m113.477877] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/17/2013] [Indexed: 01/22/2023] Open
Abstract
Mucin type O-glycosylation is initiated by a large family of polypeptide GalNAc transferases (ppGalNAc Ts) that add α-GalNAc to the Ser and Thr residues of peptides. Of the 20 human isoforms, all but one are composed of two globular domains linked by a short flexible linker: a catalytic domain and a ricin-like lectin carbohydrate binding domain. Presently, the roles of the catalytic and lectin domains in peptide and glycopeptide recognition and specificity remain unclear. To systematically study the role of the lectin domain in ppGalNAc T glycopeptide substrate utilization, we have developed a series of novel random glycopeptide substrates containing a single GalNAc-O-Thr residue placed near either the N or C terminus of the glycopeptide substrate. Our results reveal that the presence and N- or C-terminal placement of the GalNAc-O-Thr can be important determinants of overall catalytic activity and specificity that differ between transferase isoforms. For example, ppGalNAc T1, T2, and T14 prefer C-terminally placed GalNAc-O-Thr, whereas ppGalNAc T3 and T6 prefer N-terminally placed GalNAc-O-Thr. Several transferase isoforms, ppGalNAc T5, T13, and T16, display equally enhanced N- or C-terminal activities relative to the nonglycosylated control peptides. This N- and/or C-terminal selectivity is presumably due to weak glycopeptide binding to the lectin domain, whose orientation relative to the catalytic domain is dynamic and isoform-dependent. Such N- or C-terminal glycopeptide selectivity provides an additional level of control or fidelity for the O-glycosylation of biologically significant sites and suggests that O-glycosylation may in some instances be exquisitely controlled.
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Affiliation(s)
- Thomas A. Gerken
- From the Departments of Pediatrics (W. A. Bernbaum Center for Cystic Fibrosis Research)
- Biochemistry, and
- Chemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Leslie Revoredo
- Chemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Joseph J. C. Thome
- From the Departments of Pediatrics (W. A. Bernbaum Center for Cystic Fibrosis Research)
| | - Lawrence A. Tabak
- the Section on Biological Chemistry, NIDCR, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892
| | - Malene Bech Vester-Christensen
- the Copenhagen Center for Glycomics (CCG), Departments of Cellular and Molecular Medicine and Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Henrik Clausen
- the Copenhagen Center for Glycomics (CCG), Departments of Cellular and Molecular Medicine and Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Gagandeep K. Gahlay
- the Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071, and
| | - Donald L. Jarvis
- the Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071, and
| | - Roy W. Johnson
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Heather A. Moniz
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Kelley Moremen
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
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Razawi H, Kinlough CL, Staubach S, Poland PA, Rbaibi Y, Weisz OA, Hughey RP, Hanisch FG. Evidence for core 2 to core 1 O-glycan remodeling during the recycling of MUC1. Glycobiology 2013; 23:935-45. [PMID: 23640779 DOI: 10.1093/glycob/cwt030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The apical transmembrane glycoprotein MUC1 is endocytosed to recycle through the trans-Golgi network (TGN) or Golgi complex to the plasma membrane. We followed the hypothesis that not only the known follow-up sialylation of MUC1 in the TGN is associated with this process, but also a remodeling of O-glycan core structures, which would explain the previously described differential core 2- vs core 1-based O-glycosylation of secreted, single Golgi passage and recycling membrane MUC1 isoforms (Engelmann K, Kinlough CL, Müller S, Razawi H, Baldus SE, Hughey RP, Hanisch F-G. 2005. Glycobiology. 15:1111-1124). Transmembrane and secreted MUC1 probes show trafficking-dependent changes in O-glycan core profiles. To address this novel observation, we used recombinant epitope-tagged MUC1 (MUC1-M) and mutant forms with abrogated clathrin-mediated endocytosis (MUC1-M-Y20,60N) or blocked recycling (palmitoylation-defective MUC1-M-CQC/AQA). We show that the CQC/AQA mutant transits the TGN at significantly lower levels, concomitant with a strongly reduced shedding from the plasma membrane and its accumulation in endosomal compartments. Intriguingly, the O-glycosylation of the shed MUC1 ectodomain subunit changes from preponderant sialylated core 1 (MUC1-M) to core 2 glycans on the non-recycling CQC/AQA mutant. The O-glycoprofile of the non-recycling CQC/AQA mutant resembles the core 2 glycoprofile on a secretory MUC1 probe that transits the Golgi complex only once. In contrast, the MUC1-M-Y20,60N mutant recycles via flotillin-dependent pathways and shows the wild-type phenotype with dominant core 1 expression. Differential radiolabeling of protein with [(35)S]Met/Cys or glycans with [(3)H]GlcNH2 in pulse-chase experiments of surface biotinylated MUC1 revealed a significantly shorter half-life of [(3)H]MUC1 when compared with [(35)S]MUC1, whereas the same ratio for the CQC/AQA mutant was close to one. This finding further supports the novel possibility of a recycling-associated O-glycan processing from Gal1-4GlcNAc1-6(Gal1-3)GalNAc (core 2) to Gal1-3GalNAc (core 1).
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Affiliation(s)
- Hanieh Razawi
- Medical Faculty, Institute of Biochemistry II, University of Cologne, 50931 Köln, Germany
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28
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Youker RT, Bruns JR, Costa SA, Rbaibi Y, Lanni F, Kashlan OB, Teng H, Weisz OA. Multiple motifs regulate apical sorting of p75 via a mechanism that involves dimerization and higher-order oligomerization. Mol Biol Cell 2013; 24:1996-2007. [PMID: 23637462 PMCID: PMC3681702 DOI: 10.1091/mbc.e13-02-0078] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The sorting signals that direct proteins to the apical surface of polarized epithelial cells are complex and can include posttranslational modifications, such as N- and O-linked glycosylation. Efficient apical sorting of the neurotrophin receptor p75 is dependent on its O-glycosylated membrane proximal stalk, but how this domain mediates targeting is unknown. Protein oligomerization or clustering has been suggested as a common step in the segregation of all apical proteins. Like many apical proteins, p75 forms dimers, and we hypothesized that formation of higher-order clusters mediated by p75 dimerization and interactions of the stalk facilitate its apical sorting. Using fluorescence fluctuation techniques (photon-counting histogram and number and brightness analyses) to study p75 oligomerization status in vivo, we found that wild-type p75-green fluorescent protein forms clusters in the trans-Golgi network (TGN) but not at the plasma membrane. Disruption of either the dimerization motif or the stalk domain impaired both clustering and polarized delivery. Manipulation of O-glycan processing or depletion of multiple galectins expressed in Madin-Darby canine kidney cells had no effect on p75 sorting, suggesting that the stalk domain functions as a structural prop to position other determinants in the lumenal domain of p75 for oligomerization. Additionally, a p75 mutant with intact dimerization and stalk motifs but with a dominant basolateral sorting determinant (Δ250 mutant) did not form oligomers, consistent with a requirement for clustering in apical sorting. Artificially enhancing dimerization restored clustering to the Δ250 mutant but was insufficient to reroute this mutant to the apical surface. Together these studies demonstrate that clustering in the TGN is required for normal biosynthetic apical sorting of p75 but is not by itself sufficient to reroute a protein to the apical surface in the presence of a strong basolateral sorting determinant. Our studies shed new light on the hierarchy of polarized sorting signals and on the mechanisms by which newly synthesized proteins are segregated in the TGN for eventual apical delivery.
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Affiliation(s)
- Robert T Youker
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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29
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Gnanapragassam VS, Jain M, Batra SK. Analysis of tumor-associated mucin glycotopes by Western transfer methods. Methods Mol Biol 2013; 980:331-40. [PMID: 23359164 DOI: 10.1007/978-1-62703-287-2_19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In mucins, glycosylation is complex and the most predominant posttranslational modification. Since mucins exhibit differential glycosylation pattern under physiological and pathological conditions, analysis of mucin glycans is important for understanding their specific functions during pathological conditions like cancer. Given the complexity of mucin glycans, several sophisticated analytical tools such as HPLC, mass spectrometry, and lectin sandwich assays are employed for glyco-analysis of mucins. However the specialized expertise and instrumentation required for such analysis are beyond the reach of an average cancer biology laboratory. We described in this chapter the utility of the simple electrophoresis/immunoblotting method to examine the mucin glycan epitopes, using specific antibodies and lectins.
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Affiliation(s)
- Vinayaga S Gnanapragassam
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
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30
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Mo D, Costa SA, Ihrke G, Youker RT, Pastor-Soler N, Hughey RP, Weisz OA. Sialylation of N-linked glycans mediates apical delivery of endolyn in MDCK cells via a galectin-9-dependent mechanism. Mol Biol Cell 2012; 23:3636-46. [PMID: 22855528 PMCID: PMC3442411 DOI: 10.1091/mbc.e12-04-0329] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The sialomucin endolyn is implicated in adhesion, migration, and differentiation of various cell types. Apical delivery of endolyn requires recognition of sialic acids on its N-glycans possibly (or likely) mediated by galectin-9. The sialomucin endolyn is implicated in adhesion, migration, and differentiation of various cell types. Along rat kidney tubules, endolyn is variously localized to the apical surface and endosomal/lysosomal compartments. Apical delivery of newly synthesized rat endolyn predominates over direct lysosomal delivery in polarized Madin–Darby canine kidney cells. Apical sorting depends on terminal processing of a subset of lumenal N-glycans. Here we dissect the requirements of N-glycan processing for apical targeting and investigate the underlying mechanism. Modulation of glycan branching and subsequent polylactosamine elongation by knockdown of N-acetylglucosaminyltransferase III or V had no effect on apical delivery of endolyn. In contrast, combined but not individual knockdown of sialyltransferases ST3Gal-III, ST3Gal-IV, and ST6Gal-I, which together are responsible for addition of α2,3- and α2,6-linked sialic acids on N-glycans, dramatically decreased endolyn surface polarity. Endolyn synthesized in the presence of kifunensine, which blocks terminal N-glycan processing, reduced its interaction with several recombinant canine galectins, and knockdown of galectin-9 (but not galectin-3, -4, or -8) selectively disrupted endolyn polarity. Our data suggest that sialylation enables recognition of endolyn by galectin-9 to mediate efficient apical sorting. They raise the intriguing possibility that changes in glycosyltransferase expression patterns and/or galectin-9 distribution may acutely modulate endolyn trafficking in the kidney.
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Affiliation(s)
- Di Mo
- Renal Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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31
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Mattila PE, Youker RT, Mo D, Bruns JR, Cresawn KO, Hughey RP, Ihrke G, Weisz OA. Multiple biosynthetic trafficking routes for apically secreted proteins in MDCK cells. Traffic 2011; 13:433-42. [PMID: 22118573 DOI: 10.1111/j.1600-0854.2011.01315.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 11/21/2011] [Accepted: 11/21/2011] [Indexed: 11/30/2022]
Abstract
Many newly synthesized membrane proteins traverse endocytic intermediates en route to the surface in polarized epithelial cells; however, the biosynthetic itinerary of secreted proteins has not been elucidated. We monitored the trafficking route of two secreted proteins with different apical sorting signals: the N-glycan-dependent cargo glycosylated growth hormone (gGH) and Ensol, a soluble version of endolyn whose apical sorting is independent of N-glycans. Both proteins were observed to colocalize in part with apical recycling endosome (ARE) markers. Cargo that lacks an apical targeting signal and is secreted in a nonpolarized manner did not localize to the ARE. Expression of a dominant-negative mutant of myosin Vb, which disrupts ARE export of glycan-dependent membrane proteins, selectively inhibited apical release of gGH but not Ensol. Fluorescence recovery after photobleaching (FRAP) measurements revealed that gGH in the ARE was less mobile than Ensol, consistent with tethering to a sorting receptor. However, knockdown of galectin-3 or galectin-4, lectins implicated in apical sorting, had no effect on the rate or polarity of gGH secretion. Together, our results suggest that apically secreted cargoes selectively access the ARE and are exported via differentially regulated pathways.
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Affiliation(s)
- Polly E Mattila
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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