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Hunter C, Derksen T, Makhsous S, Doll M, Perez SR, Scott NE, Willis LM. Site-specific immobilization of the endosialidase reveals QSOX2 is a novel polysialylated protein. Glycobiology 2024; 34:cwae026. [PMID: 38489772 PMCID: PMC11031136 DOI: 10.1093/glycob/cwae026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 03/04/2024] [Accepted: 03/13/2024] [Indexed: 03/17/2024] Open
Abstract
Polysialic acid (polySia) is a linear polymer of α2,8-linked sialic acid residues that is of fundamental biological interest due to its pivotal roles in the regulation of the nervous, immune, and reproductive systems in healthy human adults. PolySia is also dysregulated in several chronic diseases, including cancers and mental health disorders. However, the mechanisms underpinning polySia biology in health and disease remain largely unknown. The polySia-specific hydrolase, endoneuraminidase NF (EndoN), and the catalytically inactive polySia lectin EndoNDM, have been extensively used for studying polySia. However, EndoN is heat stable and remains associated with cells after washing. When studying polySia in systems with multiple polysialylated species, the residual EndoN that cannot be removed confounds data interpretation. We developed a strategy for site-specific immobilization of EndoN on streptavidin-coated magnetic beads. We showed that immobilizing EndoN allows for effective removal of the enzyme from samples, while retaining hydrolase activity. We used the same strategy to immobilize the polySia lectin EndoNDM, which enabled the enrichment of polysialylated proteins from complex mixtures such as serum for their identification via mass spectrometry. We used this methodology to identify a novel polysialylated protein, QSOX2, which is secreted from the breast cancer cell line MCF-7. This method of site-specific immobilization can be utilized for other enzymes and lectins to yield insight into glycobiology.
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Affiliation(s)
- Carmanah Hunter
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Tahlia Derksen
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Sogand Makhsous
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Matt Doll
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Samantha Rodriguez Perez
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC 3000, Australia
| | - Lisa M Willis
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
- Department of Medical Microbiology and Immunology, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
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Khan L, Derksen T, Redmond D, Storek J, Durand C, Gniadecki R, Korman B, Cohen Tervaert JW, D'Aubeterre A, Osman MS, Willis LM. The cancer-associated glycan polysialic acid is dysregulated in systemic sclerosis and is associated with fibrosis. J Autoimmun 2023; 140:103110. [PMID: 37742510 DOI: 10.1016/j.jaut.2023.103110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/28/2023] [Accepted: 09/03/2023] [Indexed: 09/26/2023]
Abstract
OBJECTIVE Systemic sclerosis (SSc) is a rare but deadly disease characterized by autoimmunity, vasculopathy, and fibrosis. Fibrotic complications associated with SSc correlate with severe morbidity and mortality. Previous studies in SSc have identified fibroblasts as the primary drivers of fibrosis; however, the mechanism(s) promoting this are not well understood. Aberrant glycosylation, particularly polysialylation (polySia), has been described as a prominent feature of aggressive cancers. Inspired by this observation, we aimed to determine if polySia is dysregulated in various forms of SSc. METHODS All patients with SSc met the 2013 ACR/EULAR. Patients were sub-classified into limited cutaneous (lSSc, N = 5 or 46 patients for polySia quantification in the dermis or serum; respectively), diffuse cutaneous (dSSc, N = 11 or 18 patients for polySia quantification in the dermis or serum; respectively), or patients with dSSc treated with an autologous stem cell transplantation (post-ASCT, N = 4 patients for quantification in the dermis). Dermal polySia levels were measured via immunofluorescence microscopy in 10 μm dermal sections, quantified in each group (healthy volunteers (HC), lSSc, dSSc, and post-ASCT) and correlated with skin fibrosis (via the modified Rodnan skin score (mRSS)). Similarly, serum polySia was quantified in each group, and correlated with the mRSS. RESULTS Dermal polySia levels were highest in patients with dSSc (compared to HC < 0.001), and correlated with the degree of fibrosis in all of the groups (P = 0.008). Serum polySia was higher in all SSc groups (p < 0.001) and correlated with the severity of mRSS (p < 0.0001). CONCLUSION Polysia is more abundant in the skin and sera from patients with SSc and correlates with the degree of skin fibrosis. The aberrant expression of polySia highlights its potential use as a biomarker in patients with progressive forms of SSc. Dysregulated polySia levels in SSc further emphasizes the cancer-like phenotype present in SSc, which may promote fibrosis and immune dysregulation.
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Affiliation(s)
- Lamia Khan
- Faculty of Medicine & Dentistry, Division of Rheumatology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Tahlia Derksen
- Faculty of Science, Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Desiree Redmond
- Faculty of Medicine & Dentistry, Division of Rheumatology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Jan Storek
- University of Calgary, Calgary, AB, Canada
| | | | - Robert Gniadecki
- Faculty of Medicine & Dentistry, Division of Dermatology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Benjamin Korman
- Division of Allergy, Immunology and Rheumatology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jan Willem Cohen Tervaert
- Faculty of Medicine & Dentistry, Division of Rheumatology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Ana D'Aubeterre
- Faculty of Science, Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Mohammed S Osman
- Faculty of Medicine & Dentistry, Division of Rheumatology, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
| | - Lisa M Willis
- Faculty of Science, Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada; Faculty of Medicine & Dentistry, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada.
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Hunter CD, Morris KM, Derksen T, Willis LM. The sweet side of sex as a biological variable. Glycobiology 2023:7109779. [PMID: 37021826 DOI: 10.1093/glycob/cwad030] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 03/30/2023] [Accepted: 04/04/2023] [Indexed: 04/07/2023] Open
Abstract
Glycobiology as a field holds enormous potential for understanding human health and disease. However, few glycobiology studies adequately address the issue of sex differences in biology, which severely limits the conclusions that can be drawn. Numerous CAZymes, lectins, and other carbohydrate-associated molecules have the potential to be differentially expressed and regulated with sex, leading to differences in O-GlcNAc, N-glycan branching, fucosylation, sialylation, and proteoglycan structure, among others. Expression of proteins involved in glycosylation is influenced through hormones, miRNA, and gene dosage effects. In this review, we discuss the benefits of incorporating sex-based analysis in glycobiology research and the potential drivers of sex differences. We highlight examples of where incorporation of sex-based analysis has led to insights into glycobiology. Finally, we offer suggestions for how to proceed moving forward, even if the experiments are already complete. Properly incorporating sex based analyses into projects will substantially improve the accuracy and reproducibility of studies as well as accelerate the rate of discovery in the glycosciences.
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Affiliation(s)
- Carmanah D Hunter
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Kaylee M Morris
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Tahlia Derksen
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Lisa M Willis
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
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4
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Hunter C, Gao Z, Chen HM, Thompson N, Wakarchuk W, Nitz M, Withers SG, Willis LM. Attenuation of Polysialic Acid Biosynthesis in Cells by the Small Molecule Inhibitor 8-Keto-sialic acid. ACS Chem Biol 2023; 18:41-48. [PMID: 36577399 DOI: 10.1021/acschembio.2c00638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Sialic acids are key mediators of cell function, particularly with regard to cellular interactions with the surrounding environment. Reagents that modulate the display of specific sialyl glycoforms at the cell surface would be useful biochemical tools and potentially allow for therapeutic intervention in numerous challenging chronic diseases. While multiple strategies are being explored for the control of cell surface sialosides, none that shows high selectivity between sialyltransferases or that targets a specific sialyl glycoform has yet to emerge. Here, we describe a strategy to block the formation of α2,8-linked sialic acid chains (oligo- and polysialic acid) through the use of 8-keto-sialic acid as a chain-terminating metabolic inhibitor that, if incorporated, cannot be elongated. 8-Keto-sialic acid is nontoxic at effective concentrations and serves to block polysialic acid synthesis in cancer cell lines and primary immune cells, with minimal effects on other sialyl glycoforms.
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Affiliation(s)
- Carmanah Hunter
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Zhizeng Gao
- Department of Chemistry, University of British Columbia, Vancouver, V6T 1Z1, Canada
| | - Hong-Ming Chen
- Department of Chemistry, University of Toronto, Toronto, M5S 3H6, Canada
| | - Nicole Thompson
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Warren Wakarchuk
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, M5S 3H6, Canada
| | - Stephen G Withers
- Department of Chemistry, University of British Columbia, Vancouver, V6T 1Z1, Canada
| | - Lisa M Willis
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2R3, Canada
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Goings F, Wilson NL, Equiza A, Lefsrud LM, Willis LM. Margaret-Ann Armour and WISEST – an incredible legacy in advancing women in science, technology, engineering, and mathematics (STEM) and the work still to do. CAN J CHEM 2021. [DOI: 10.1139/cjc-2020-0328] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dr. Margaret-Ann Armour was a visionary and leader in addressing the issue of gender inclusivity and discrimination in science, technology, engineering, and mathematics (STEM). She was instrumental in creating WISEST — Women in Scholarship, Engineering, Science, and Technology — in 1982, which was one of the first programs in Canada intentionally designed to increase the participation of women and girls in STEM career paths. Since then, this innovative organization has designed several programs featuring hands-on learning and mentoring that reduce barriers and empower people from underrepresented and marginalized groups to pursue education and careers in STEM fields. This review provides a template for WISEST programs, discusses their impact on diversity in STEM, and highlights the work still to be done.
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Affiliation(s)
| | - Nicole L. Wilson
- Office of the Dean, Faculty of Engineering, University of Alberta, Edmonton, AB
| | - Ale Equiza
- Office of Advancement, University of Alberta, Edmonton, AB
| | - Lianne M. Lefsrud
- Lynch School of Engineering Safety and Risk Management, Department of Chemical and Materials Engineering, Faculty of Engineering, University of Alberta, Edmonton, AB
| | - Lisa M. Willis
- Department of Biological Sciences, University of Alberta, Edmonton, AB
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6
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Liston SD, Willis LM. Racing to build a wall: glycoconjugate assembly in Gram-positive and Gram-negative bacteria. Curr Opin Struct Biol 2021; 68:55-65. [PMID: 33429200 DOI: 10.1016/j.sbi.2020.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 12/17/2022]
Abstract
The last two years have seen major advances in understanding the structural basis of bacterial cell envelope glycoconjugate biosynthesis, including capsules, lipopolysaccharide, teichoic acid, cellulose, and peptidoglycan. The recent crystal and cryo-electron microscopy structures of proteins involved in the initial glycosyltransferase steps in the cytoplasm, the transport of large and small lipid-linked glycoconjugates across the inner membrane, the polymerization of glycans in the periplasm, and the export of molecules from the cell have shed light on the mechanisms by which cell envelope glycoconjugates are made. We discuss these recent advances and highlight remaining unanswered questions.
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Affiliation(s)
- Sean D Liston
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5G1M1, Canada
| | - Lisa M Willis
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G2T2, Canada; Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, T6G2T2, Canada; Women and Children's Health Research Institute, Edmonton, AB, T6G2T2, Canada.
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7
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Willis LM, Mehta D, Davis A. Twelve Principles Trainees, PIs, Departments, and Faculties Can Use to Reduce Bias and Discrimination in STEM. ACS Cent Sci 2020; 6:2294-2300. [PMID: 33376790 PMCID: PMC7760482 DOI: 10.1021/acscentsci.0c01120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Indexed: 06/12/2023]
Abstract
There is an overwhelming amount of evidence demonstrating that people from marginalized groups, including women, racialized and Indigenous peoples, people with disabilities, immigrants, and LGBTQ+ individuals, continue to face substantial discrimination in STEM, manifested as both overt bias and unconscious bias. These biases result in discrimination against individuals in marginalized groups, and independent biases collectively contribute to a culture that systematically discriminates against people from marginalized groups. Representation from marginalized groups in postsecondary degrees in natural science and engineering has not substantially improved in over a decade. A set of 10 concrete principles are presented that trainees, principle investigators, departments, and faculties can use to enhance the participation and lived experiences of people in marginalized groups in STEM.
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8
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Tajik A, Phillips KL, Nitz M, Willis LM. A new ELISA assay demonstrates sex differences in the concentration of serum polysialic acid. Anal Biochem 2020; 600:113743. [DOI: 10.1016/j.ab.2020.113743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/01/2020] [Accepted: 04/14/2020] [Indexed: 12/20/2022]
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Bassan J, Willis LM, Vellanki RN, Nguyen A, Edgar LJ, Wouters BG, Nitz M. TePhe, a tellurium-containing phenylalanine mimic, allows monitoring of protein synthesis in vivo with mass cytometry. Proc Natl Acad Sci U S A 2019; 116:8155-8160. [PMID: 30971489 PMCID: PMC6486722 DOI: 10.1073/pnas.1821151116] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Protein synthesis is central to maintaining cellular homeostasis and its study is critical to understanding the function and dysfunction of eukaryotic systems. Here we report L-2-tellurienylalanine (TePhe) as a noncanonical amino acid for direct measurement of protein synthesis. TePhe is synthetically accessible, nontoxic, stable under biological conditions, and the tellurium atom allows its direct detection with mass cytometry, without postexperiment labeling. TePhe labeling is competitive with phenylalanine but not other large and aromatic amino acids, demonstrating its molecular specificity as a phenylalanine mimic; labeling is also abrogated in vitro and in vivo by the protein synthesis inhibitor cycloheximide, validating TePhe as a translation reporter. In vivo, imaging mass cytometry with TePhe visualizes translation dynamics in the mouse gut, brain, and tumor. The strong performance of TePhe as a probe for protein synthesis, coupled with the operational simplicity of its use, suggests TePhe could become a broadly applied molecule for measuring translation in vitro and in vivo.
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Affiliation(s)
- Jay Bassan
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6
| | - Lisa M Willis
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6
| | - Ravi N Vellanki
- The Campbell Family Institute for Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada M5T 2M9
| | - Alan Nguyen
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6
| | - Landon J Edgar
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6
| | - Bradly G Wouters
- The Campbell Family Institute for Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada M5T 2M9
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada M5S 3E2
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 3H6;
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10
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Willis LM, Park H, Watson MWL, Majonis D, Watson JL, Nitz M. Tellurium-based mass cytometry barcode for live and fixed cells. Cytometry A 2018; 93:685-694. [DOI: 10.1002/cyto.a.23495] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 03/15/2018] [Accepted: 04/26/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Lisa M. Willis
- Department of Chemistry; University of Toronto; Toronto Ontario M5S 3H6 Canada
| | - Hanuel Park
- Department of Chemistry; University of Toronto; Toronto Ontario M5S 3H6 Canada
| | - Michael W. L. Watson
- Fluidigm Corporation, 7000 Shoreline Court; South San Francisco California 94080
| | - Daniel Majonis
- Fluidigm Canada Inc.; 1380 Rodick Road, Markham Ontario L3R 4G5 Canada
| | - Jessica L. Watson
- Fluidigm Canada Inc.; 1380 Rodick Road, Markham Ontario L3R 4G5 Canada
| | - Mark Nitz
- Department of Chemistry; University of Toronto; Toronto Ontario M5S 3H6 Canada
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11
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Abstract
Using a MALDI-MS based assay, the kinetic parameters for peptide glucosylation using the C. difficile toxin B glycosyltransferase domain were determined. The minimum consensus sequence for glucosylation was YXXTXFXXY and the optimal peptide found was YAPTVFDAY. Using this sequence, homogenous glucosylated proteins could be readily produced.
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Affiliation(s)
- Y Sun
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - L M Willis
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - H R Batchelder
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - M Nitz
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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12
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Abstract
Tellurophenes are promising biocompatible mass tags.
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Affiliation(s)
- Hanuel Park
- Department of Chemistry
- University of Toronto
- Toronto 80 St. George St
- Canada
| | - Landon J. Edgar
- Department of Chemistry
- University of Toronto
- Toronto 80 St. George St
- Canada
| | - Matthew A. Lumba
- Department of Chemistry
- University of Toronto
- Toronto 80 St. George St
- Canada
| | - Lisa M. Willis
- Department of Chemistry
- University of Toronto
- Toronto 80 St. George St
- Canada
| | - Mark Nitz
- Department of Chemistry
- University of Toronto
- Toronto 80 St. George St
- Canada
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Willis LM, Whitfield C. Structure, biosynthesis, and function of bacterial capsular polysaccharides synthesized by ABC transporter-dependent pathways. Carbohydr Res 2013; 378:35-44. [PMID: 23746650 DOI: 10.1016/j.carres.2013.05.007] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/06/2013] [Accepted: 05/11/2013] [Indexed: 12/11/2022]
Abstract
Bacterial capsules are formed primarily from long-chain polysaccharides with repeat-unit structures. A given bacterial species can produce a range of capsular polysaccharides (CPSs) with different structures and these help distinguish isolates by serotyping, as is the case with Escherichia coli K antigens. Capsules are important virulence factors for many pathogens and this review focuses on CPSs synthesized via ATP-binding cassette (ABC) transporter-dependent processes in Gram-negative bacteria. Bacteria utilizing this pathway are often associated with urinary tract infections, septicemia, and meningitis, and E. coli and Neisseria meningitidis provide well-studied examples. CPSs from ABC transporter-dependent pathways are synthesized at the cytoplasmic face of the inner membrane through the concerted action of glycosyltransferases before being exported across the inner membrane and translocated to the cell surface. A hallmark of these CPSs is a conserved reducing terminal glycolipid composed of phosphatidylglycerol and a poly-3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) linker. Recent discovery of the structure of this conserved lipid terminus provides new insights into the early steps in CPS biosynthesis.
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Affiliation(s)
- Lisa M Willis
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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14
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Willis LM, Stupak J, Richards MR, Lowary TL, Li J, Whitfield C. Conserved glycolipid termini in capsular polysaccharides synthesized by ATP-binding cassette transporter-dependent pathways in Gram-negative pathogens. Proc Natl Acad Sci U S A 2013; 110:7868-73. [PMID: 23610430 PMCID: PMC3651472 DOI: 10.1073/pnas.1222317110] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Bacterial capsules are surface layers made of long-chain polysaccharides. They are anchored to the outer membrane of many Gram-negative bacteria, including pathogens such as Escherichia coli, Neisseria meningitidis, Haemophilus influenzae, and Pasteurella multocida. Capsules protect pathogens from host defenses including complement-mediated killing and phagocytosis and therefore represent a major virulence factor. Capsular polysaccharides are synthesized by enzymes located in the inner (cytoplasmic) membrane and are then translocated to the cell surface. Whereas the enzymes that synthesize the polysaccharides have been studied in detail, the structure and biosynthesis of the anchoring elements have not been definitively resolved. Here we determine the structure of the glycolipid attached to the reducing terminus of the polysialic acid capsular polysaccharides from E. coli K1 and N. meningitidis group B and the heparosan-like capsular polysaccharide from E. coli K5. All possess the same unique glycolipid terminus consisting of a lyso-phosphatidylglycerol moiety with a β-linked poly-(3-deoxy-d-manno-oct-2-ulosonic acid) (poly-Kdo) linker attached to the reducing terminus of the capsular polysaccharide.
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Affiliation(s)
- Lisa M. Willis
- Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Jacek Stupak
- National Research Council Canada, Ottawa, ON, Canada K1A 0Z3; and
| | - Michele R. Richards
- Alberta Glycomics Centre and
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Todd L. Lowary
- Alberta Glycomics Centre and
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada T6G 2G2
| | - Jianjun Li
- National Research Council Canada, Ottawa, ON, Canada K1A 0Z3; and
| | - Chris Whitfield
- Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
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Larue K, Ford RC, Willis LM, Whitfield C. Functional and structural characterization of polysaccharide co-polymerase proteins required for polymer export in ATP-binding cassette transporter-dependent capsule biosynthesis pathways. J Biol Chem 2011; 286:16658-68. [PMID: 21454677 PMCID: PMC3089508 DOI: 10.1074/jbc.m111.228221] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 03/17/2011] [Indexed: 11/06/2022] Open
Abstract
Neisseria meningitidis serogroup B and Escherichia coli K1 bacteria produce a capsular polysaccharide (CPS) that is composed of α2,8-linked polysialic acid (PSA). Biosynthesis of PSA in these bacteria occurs via an ABC (ATP-binding cassette) transporter-dependent pathway. In N. meningitidis, export of PSA to the surface of the bacterium requires two proteins that form an ABC transporter (CtrC and CtrD) and two additional proteins, CtrA and CtrB, that are proposed to form a cell envelope-spanning export complex. CtrA is a member of the outer membrane polysaccharide export (OPX) family of proteins, which are proposed to form a pore to mediate export of CPSs across the outer membrane. CtrB is an inner membrane protein belonging to the polysaccharide co-polymerase (PCP) family. PCP proteins involved in other bacterial polysaccharide assembly systems form structures that extend into the periplasm from the inner membrane. There is currently no structural information available for PCP or OPX proteins involved in an ABC transporter-dependent CPS biosynthesis pathway to support their proposed roles in polysaccharide export. Here, we report cryo-EM images of purified CtrB reconstituted into lipid bilayers. These images contained molecular top and side views of CtrB and showed that it formed a conical oligomer that extended ∼125 Å from the membrane. This structure is consistent with CtrB functioning as a component of an envelope-spanning complex. Cross-complementation of CtrA and CtrB in E. coli mutants with defects in genes encoding the corresponding PCP and OPX proteins show that PCP-OPX pairs require interactions with their cognate partners to export polysaccharide. These experiments add further support for the model of an ABC transporter-PCP-OPX multiprotein complex that functions to export CPS across the cell envelope.
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Affiliation(s)
- Kane Larue
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 and
| | - Robert C. Ford
- the Faculty of Life Science, University of Manchester, Manchester M60 1QD, United Kingdom
| | - Lisa M. Willis
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 and
| | - Chris Whitfield
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 and
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Willis LM, Zhang R, Reid A, Withers SG, Wakarchuk WW. Mechanistic investigation of the endo-alpha-N-acetylgalactosaminidase from Streptococcus pneumoniae R6. Biochemistry 2009; 48:10334-41. [PMID: 19788271 DOI: 10.1021/bi9013825] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The large (1767-amino acid) endo-alpha-N-acetylgalactosaminidase from Streptococcus pneumoniae (SpGH101) specifically removes an O-linked disaccharide Gal-beta-1,3-GalNAc-alpha from glycoproteins. While the enzyme from natural sources has been used as a reagent for many years, very few mechanistic studies have been performed. Using the recently determined three-dimensional structure of the recombinant protein as a background, we report here a mechanistic investigation of the SpGH101 retaining alpha-glycoside hydrolase using a combination of synthetic and natural substrates. On the basis of a model of the substrate complex of SpGH101, we propose D764 and E796 as the nucleophile and general acid-base residues, respectively. These roles were confirmed by kinetic and mechanistic analysis of mutants at those positions using synthetic substrates and anion rescue experiments. pK(a) values of 5.3 and 7.2 were assigned to D764 and E796 on the basis of the pK(a) values derived from the bell-shaped dependence of k(cat)/K(m) upon pH. The enzyme contains several putative carbohydrate binding modules whose glycan binding specificities were probed using the printed glycan array of the Consortium for Functional Glycomics using the inactive D764A and D764F mutants that had been labeled with Alexafluor 488. These studies revealed binding to galacto-N-biose, consistent with a role for these domains in localizing the enzyme near its substrates.
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Affiliation(s)
- Lisa M Willis
- Glycobiology Program, Institute for Biological Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
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Morley TJ, Willis LM, Whitfield C, Wakarchuk WW, Withers SG. A new sialidase mechanism: bacteriophage K1F endo-sialidase is an inverting glycosidase. J Biol Chem 2009; 284:17404-10. [PMID: 19411257 PMCID: PMC2719380 DOI: 10.1074/jbc.m109.003970] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Indexed: 12/15/2022] Open
Abstract
Bacteriophages specific for Escherichia coli K1 express a tailspike protein that degrades the polysialic acid coat of E. coli K1 that is essential for bacteriophage infection. This enzyme is specific for polysialic acid and is a member of a family of endo-sialidases. This family is unusual because all other previously reported sialidases outside of this family are exo- or trans-sialidases. The recently determined structure of an endo-sialidase derived from bacteriophage K1F (endoNF) revealed an active site that lacks a number of the residues that are conserved in other sialidases, implying a new, endo-sialidase-specific catalytic mechanism. Using synthetic trifluoromethylumbelliferyl oligosialoside substrates, kinetic parameters for hydrolysis at a single cleavage site were determined. Measurement of kcat/Km at a series of pH values revealed a dependence on a single protonated group of pKa 5. Mutation of a putative active site acidic residue, E581A, resulted in complete loss of sialidase activity. Direct 1H NMR analysis of the hydrolysis of trifluoromethylumbelliferyl sialotrioside revealed that endoNF is an inverting sialidase. All other wild type sialidases previously reported are retaining glycosidases, implying a new mechanism of sialidase action specific to this family of endo-sialidases.
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Affiliation(s)
- Thomas J. Morley
- From the Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1
| | - Lisa M. Willis
- the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, and
| | - Chris Whitfield
- the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, and
| | - Warren W. Wakarchuk
- the Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Stephen G. Withers
- From the Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1
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Caines ME, Zhu H, Vuckovic M, Willis LM, Withers SG, Wakarchuk WW, Strynadka NC. The Structural Basis for T-antigen Hydrolysis by Streptococcus pneumoniae. J Biol Chem 2008; 283:31279-83. [DOI: 10.1074/jbc.c800150200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Quintero EM, Willis LM, Zaman V, Lee J, Boger HA, Tomac A, Hoffer BJ, Strömberg I, Granholm AC. Glial cell line-derived neurotrophic factor is essential for neuronal survival in the locus coeruleus–hippocampal noradrenergic pathway. Neuroscience 2004; 124:137-46. [PMID: 14960346 DOI: 10.1016/j.neuroscience.2003.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2003] [Indexed: 11/19/2022]
Abstract
It has been shown that the noradrenergic (NE) locus coeruleus (LC)-hippocampal pathway plays an important role in learning and memory processing, and that the development of this transmitter pathway is influenced by neurotrophic factors. Although some of these factors have been discovered, the regulatory mechanisms for this developmental event have not been fully elucidated. Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor influencing LC-NE neurons. We have utilized a GDNF knockout animal model to explore its function on the LC-NE transmitter system during development, particularly with respect to target innervation. By transplanting various combinations of brainstem (including LC) and hippocampal tissues from wildtype or GDNF knockout fetuses into the brains of adult wildtype mice, we demonstrate that normal postnatal development of brainstem LC-NE neurons is disrupted as a result of the GDNF null mutation. Tyrosine hydroxylase immunohistochemistry revealed that brainstem grafts had markedly reduced number and size of LC neurons in transplants from knockout fetuses. NE fiber innervation into the hippocampal co-transplant from an adjacent brainstem graft was also influenced by the presence of GDNF, with a significantly more robust innervation observed in transplants from wildtype fetuses. The most successful LC/hippocampal co-grafts were generated from fetuses expressing the wildtype GDNF background, whereas the most severely affected transplants were derived from double transplants from null-mutated fetuses. Our data suggest that development of the NE LC-hippocampal pathway is dependent on the presence of GDNF, most likely through a target-derived neurotrophic function.
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Affiliation(s)
- E M Quintero
- Department of Physiology and Neuroscience and the Center on Aging, Medical University of South Carolina, 26 Bee Street, Charleston, SC 29425, USA
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Willis LM. An abstract: Technique and philosophy for the treatment of Class II skeletal and dental malocclusions. J Am Acad Gnathol Orthop 1999; 16:4-11. [PMID: 10825852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Willis LM. Treatment of an adult male with a Class II division 2 deep bite and missing upper first bicuspids. J Am Acad Gnathol Orthop 1998; 15:10-13. [PMID: 9586529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Willis LM. Case report. Dental malocclusion Class I skeletal, Division II, Class II Angle classification. J Am Acad Gnathol Orthop 1993; 10:4-5. [PMID: 9511524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Willis LM, Foster SL. Differences in children's peer sociometric and attribution ratings due to context and type of aggressive behavior. J Abnorm Child Psychol 1990; 18:199-215. [PMID: 2189923 DOI: 10.1007/bf00910731] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Sociometric and attribution (internality and responsibility) ratings of boys performing different kinds of aggression (hostile and instrumental hitting and pushing) and of neutral behavior occurring in two contexts (provoked and unprovoked) were investigated in an analogue fashion. Thirty fifth- and sixth-grade boys viewed and rated 12 brief videotaped scenes of two unfamiliar male peers interacting, presented in one of six random orders. Provoked aggression resulted in less dislike, less worthiness of punishment, and greater attribution to external causes than unprovoked aggression. Instrumental and hostile aggression produced lower liking ratings and were viewed as more deserving of punishment than neutral behavior but did not differ from each other. Results support distinctions between provoked and unprovoked aggression but not between hostile and instrumental aggression, at least in terms of their functional impact on peer judgements.
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Affiliation(s)
- L M Willis
- Department of Psychology, West Virginia University, Morgantown 26506-6040
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Abstract
In identifying the criteria which influence soldering distortion, the results of this study indicate the following: 1. Linear distortion identified at the investment phase (a net increase in gap distance) is due to setting expansion of the plaster and soldering investment. 2. The linear distortion identified at the soldering phase (a net decrease in gap distance) occurs because of the contraction of the solder. 3. The rotational distortions measured were found to be minimal. 4. The use of a minimum gap distance, without contact, is desirable. 5. Adding solder results in a well-rounded, solid solder joint.
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