Antibody and Protein Glycosylation in Health and Disease

ABSTRACT Bacterial capsular polysaccharides and lipopolysaccharides are well-established ligands of innate and adaptive immune effectors and often exhibit structural and antigenic variability. Although many surface-localized glycoproteins have been identified in bacterial pathogens and symbionts, it not clear if and how selection impacts associated glycoform structure. Here, a systematic approach was devised to correlate gene repertoire with protein-associated glycoform structure in Neisseria species important to human health and disease. By manipulating the protein glycosylation (pgl) gene content and assessing the glycan structure by mass spectrometry and reactivity with monoclonal antibodies, it was established that protein-associated glycans are antigenically variable and that at least nine distinct glycoforms can be expressed in vitro. These studies also revealed that in addition to Neisseria gonorrhoeae strain N400, one other gonococcal strain and isolates of Neisseria meningitidis and Neisseria lactamica exhibit broad-spectrum O-linked protein glycosylation. Although a strong correlation between pgl gene content, glycoform expression, and serological profile was observed, there were significant exceptions, particularly with regard to levels of microheterogeneity. This work provides a technological platform for molecular serotyping of neisserial protein glycans and for elucidating pgl gene evolution.

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Disrupted Synthesis of a Di-N-acetylated Sugar Perturbs Mature Glycoform Structure and Microheterogeneity in theO-Linked Protein Glycosylation System ofNeisseria elongatasubsp.glycolytica

Journal of Bacteriology ◽

10.1128/jb.00522-18 ◽

2018 ◽

Vol 201 (1) ◽

Cited By ~ 1

Author(s):

Nelson Wang ◽

Jan Haug Anonsen ◽

Raimonda Viburiene ◽

Joseph S. Lam ◽

Åshild Vik ◽

...

Keyword(s):

Broad Spectrum ◽

Significant Degree ◽

Protein Glycosylation ◽

Acid Biosynthesis ◽

Content Type ◽

Hexuronic Acid ◽

Major Species ◽

Genes Encoding ◽

Health And Disease

ABSTRACTThe genusNeisseriaincludes three major species of importance to human health and disease (Neisseria gonorrhoeae,Neisseria meningitidis, andNeisseria lactamica) that express broad-spectrumO-linked protein glycosylation (Pgl) systems. The potential for related Pgl systems in other species in the genus, however, remains to be determined. Using a strain ofNeisseria elongatasubsp.glycolytica, a unique tetrasaccharide glycoform consisting of di-N-acetylbacillosamine and glucose as the first two sugars followed by a rare sugar whose mass spectrometric fragmentation profile was most consistent with di-N-acetyl hexuronic acid and aN-acetylhexosamine at the nonreducing end has been identified. Based on established mechanisms for UDP-di-N-acetyl hexuronic acid biosynthesis found in other microbes, we searched for genes encoding related pathway components in theN. elongatasubsp.glycolyticagenome. Here, we detail the identification of such genes and the ensuing glycosylation phenotypes engendered by their inactivation. While the findings extend the conservative nature of microbial UDP-di-N-acetyl hexuronic acid biosynthesis, mutant glycosylation phenotypes reveal unique, relaxed specificities of the glycosyltransferases and oligosaccharyltransferases to incorporate pathway intermediate UDP-sugars into mature glycoforms.IMPORTANCEBroad-spectrum protein glycosylation (Pgl) systems are well recognized in bacteria and archaea. Knowledge of how these systems relate structurally, biochemically, and evolutionarily to one another and to others associated with microbial surface glycoconjugate expression is still incomplete. Here, we detail reverse genetic efforts toward characterization of protein glycosylation mutants ofN. elongatasubsp.glycolyticathat define the biosynthesis of a conserved but relatively rare UDP-sugar precursor. The results show both a significant degree of intra- and transkingdom conservation in the utilization of UDP-di-N-acetyl-glucuronic acid and singular properties related to the relaxed specificities of theN. elongatasubsp.glycolyticasystem

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Metabolic precision labeling enables selective probing of O-linked N-acetylgalactosamine glycosylation

10.1101/2020.04.23.057208 ◽

2020 ◽

Cited By ~ 1

Author(s):

Marjoke F. Debets ◽

Omur Y. Tastan ◽

Simon P. Wisnovsky ◽

Stacy A. Malaker ◽

Nikolaos Angelis ◽

...

Keyword(s):

Cell Surface ◽

Secretory Pathway ◽

Protein Glycosylation ◽

Surface Proteins ◽

Major Type ◽

Knock Out ◽

Biological Assays ◽

Superresolution Microscopy ◽

A Genome ◽

Health And Disease

AbstractProtein glycosylation events that happen early in the secretory pathway are often dysregulated during tumorigenesis. These events can be probed, in principle, by monosaccharides with bioorthogonal tags that would ideally be specific for distinct glycan subtypes. However, metabolic interconversion into other monosaccharides drastically reduces such specificity in the living cell. Here, we use a structure-based design process to develop the monosaccharide probe GalNAzMe that is specific for cancer-relevant Ser/Thr-N-acetylgalactosamine (O-GalNAc) glycosylation. By virtue of a branched N-acylamide side chain, GalNAzMe is not interconverted by epimerization to the corresponding N-acetylglucosamine analog like conventional GalNAc-based probes. GalNAzMe enters O-GalNAc glycosylation but does not enter other major cell surface glycan types including Asn (N)-linked glycans. We equip cells with the capacity to biosynthesize the nucleotide-sugar donor UDP-GalNAzMe from a caged precursor. Tagged with a bioorthogonal azide group, GalNAzMe serves as an O-glycan specific reporter in superresolution microscopy, chemical glycoproteomics, a genome-wide CRISPR knock-out (KO) screen, and imaging of intestinal organoids. GalNAzMe is a precision tool that allows a detailed view into the biology of a major type of cancer-relevant protein glycosylation.Significance statementA large portion of all secreted and cell surface proteins in humans are modified by Ser/Thr(O)-linked glycosylation with N-acetylgalactosamine (GalNAc). While of fundamental importance in health and disease, O-GalNAc glycosylation is technically challenging to study because of a lack of specific tools to be used in biological assays. Here, we design an O-GalNAc specific reporter molecule termed GalNAzMe to selectively label O-GalNAc glycoproteins in living human cells. GalNAzMe is compatible with a range of experiments in quantitative biology to broaden our understanding of glycosylation. We further demonstrate that labeling is genetically programmable by expression of a mutant glycosyltransferase, allowing application even to experiments with low inherent sensitivity.

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Drug Induced Changes in Cell Organelles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100299 ◽

1968 ◽

Vol 26 ◽

pp. 110-111

Author(s):

Sarah A. Luse

Keyword(s):

Clinical Medicine ◽

Cell Organelles ◽

Riboflavin Deficiency ◽

Drug Induced ◽

New Era ◽

Health And Disease ◽

In The Beginning ◽

Cellular Pathology ◽

Induced Changes ◽

The Impact

In the mid-nineteenth century Virchow revolutionized pathology by introduction of the concept of “cellular pathology”. Today, a century later, this term has increasing significance in health and disease. We now are in the beginning of a new era in pathology, one which might well be termed “organelle pathology” or “subcellular pathology”. The impact of lysosomal diseases on clinical medicine exemplifies this role of pathology of organelles in elucidation of disease today.Another aspect of cell organelles of prime importance is their pathologic alteration by drugs, toxins, hormones and malnutrition. The sensitivity of cell organelles to minute alterations in their environment offers an accurate evaluation of the site of action of drugs in the study of both function and toxicity. Examples of mitochondrial lesions include the effect of DDD on the adrenal cortex, riboflavin deficiency on liver cells, elevated blood ammonia on the neuron and some 8-aminoquinolines on myocardium.

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The Laryngeal Epithelium in Reflux

Perspectives on Voice and Voice Disorders ◽

10.1044/vvd21.3.112 ◽

2011 ◽

Vol 21 (3) ◽

pp. 112-117 ◽

Cited By ~ 2

Author(s):

Elizabeth Erickson-Levendoski ◽

Mahalakshmi Sivasankar

Keyword(s):

Laryngopharyngeal Reflux ◽

Critical Role ◽

Structure And Function ◽

Laryngeal Disease ◽

Health And Disease ◽

And Function ◽

The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

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