Global mapping of GalNAc-T isoform-specificities and O-glycosylation site-occupancy in a tissue-forming human cell line
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Fusion Lumos, Orbitrap Fusion
ORGANISM(S): Homo Sapiens (human)
TISSUE(S): Keratinocyte, Skin
SUBMITTER: 
Mathias Ingemann Nielsen
LAB HEAD: Hans H. Wandall
PROVIDER: PXD036791 | Pride | 2022-10-22
REPOSITORIES: Pride
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2021-11-25 | PXD025407 | Pride
Project description:Dr. Clausen's laboratory is interested in the structure, biosynthesis and genetic regulation of glycoconjugates, with a major focus on mucins. This laboratory is studying the glycosylation and secretion process of mucins and biological functions involving mucins. This lab is also interested in receptor modulation mediated by glycosylation or through glycosphingolipids. RNA samples from two human pancreatic cell lines. The relevance of the variable expression levels of isoforms belonging to the polypeptide GalNAc-transferase gene-family is still a puzzle to us. The polypeptide GalNAc-transferase gene family is estimated to contain 24 gene-members all participating in the initiation of mucin-type O-glycosylation. It has become apparent that each of these individual isoforms have different tissue distribution profiles and kinetic capabilities. Mucin-type O-glycosylation is thus controlled, and dependent upon the repetoir of expressed GalNAc-transferases in any given organ and cell type at any given time. We have been trying to contribute to the understanding of the ordered process controlling mucin-type O-glycosylation in both normal and malignant models, and are currently investigating a pancreatic cell line model in the lab. The pancreatic tumor cell line ASPC-1 has been found to possess low metastatic potential in mouse models, in contrast to the pancreatic tumor cell line Suit-T2 possessing high metastatic potential. Immunohistochemical analysis of both cell lines, ASPC-1 and Suit-T2, using our monoclonal antibodies to 7 isoforms has revealed great differences in the expression profile of these 7 isoforms in theses two cell lines, and for instance GalNAc-T3 has been found to be highly expressed in Suit-T2 but completely lacking in ASPC-1. Two cell lines: ASPC-1 and Suit-T2 are analyzed with 3 independent replicate prepared for each cell line.
2010-12-11 | E-GEOD-26011 | biostudies-arrayexpress
Project description:GalNAc-transferase (GalNAc-T) isoforms modify distinct subsets of the O-glycoproteome and GalNAc-type O-glycosylation is found on most proteins trafficking through the secretory pathway in metazoan cells. The O-glycoproteome is regulated by up to 20 polypeptide GalNAc-Ts and the contributions and biological functions of individual GalNAc-Ts are poorly understood. Here, we used a zinc-finger nuclease (ZFN)-directed knockout strategy to probe the contributions of the major GalNAc-Ts (GalNAc-T1 and T2) in liver cells, and explore how the GalNAc-T repertoire quantitatively affects the O-glycoproteome. We demonstrate that the majority of the O-glycoproteome is covered by redundancy, whereas distinct subsets of substrates are modified by non-redundant functions of GalNAc-T1 and T2. Differential transcriptomic analysis indicates that loss of function of a GalNAc-T induces specific transcriptional response. The non-redundant O-glycoproteome subsets for and the transcriptional responses for each isoform appeared to be related to different cellular processes, and for the GalNAc-T2 isoform supporting a role in lipid metabolism. The results demonstrate that GalNAc-Ts have non-redundant glycosylation functions, and that these may affect distinct cellular processes. The data provides a comprehensive resource for unique substrates for individual GalNAc-Ts. Our study provides a new view on the regulation of the O-glycoproteome, suggesting that the plurality of GalNAc-Ts arose to regulate distinct protein functions and cellular processes.
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Project description:Protein N-glycosylation is ubiquitous in brain and closely related to cognition and memory. Alzheimer's disease (AD) is a multifactorial disorder that lacks clear pathogenesis and treatment. Aberrant N-glycosylation has been suggested to be involved in AD pathology. While the systematic variations of protein N-glycosylation and their roles in AD have not been thoroughly investigated due to technically challenging. Here, we applied multilayered N-glycoproteomics to quantify the global protein expression, N-glycosylation sites, N-glycans, and site-specific N-glycopeptides in AD mice brains (APP/PS1 transgenic) versus wild type. The N-glycoproteome landscape exhibited the highly complex site-specific heterogeneity in AD brains. Quantitative analyses explored the generally dysregulated N-glycosylations in AD, involving proteins such as glutamate receptors, as well as fucosylated and oligo-mannose glycans. Furthermore, functional study revealed the crucial roles of N-glycosylation on proteins and neuron cells. Our work provided a robust multilayered N-glycoproteomics workflow for AD and can be applied to widespread biological systems.
2019-11-25 | PXD015335 | Pride
Project description:Glycosylation is an abundant post-translational modification of both intracellular and extracellular proteins [1]. The majority of glycans are classified as N-linked chains, where the carbohydrate moiety is attached to asparagine residues, or O-linked chains, most commonly linked to a serine or threonine. N-linked glycosylation is initiated by the oligosaccharyltransferase complex with only two paralogs of the catalytic subunit, whereas O-glycan initiation is more complex. There are several types of O-linked glycosylation, but among the most diverse is the mucin or GalNAc type (hereafter referred to as O-glycosylation). O-glycosylation is initiated by 20 evolutionarily conserved polypeptide GalNAc-transferases (GalNAc-Ts), which catalyze the first step in the O-glycosylation of proteins by adding GalNAc residues to threonine, serine, and tyrosine amino acids (Fig 1A). Each of the GalNAc-Ts are differentially expressed in various tissues and have both distinct and overlapping peptide substrate specificities [2-12]. Thus, the repertoire of GalNAc-Ts expressed in a given cell determines the subset and O-glycosite pattern of glycosylated proteins [13]. Substantial efforts have been made to characterize and predict the substrate specificities of GalNAc-Ts in vitro, but understanding of the in vivo specificities of the individual GalNAc-Ts or their biological functions is limited [13-15]. This lack of insight prevents an understanding of how site-specific O-linked glycosylation affects diseases, such as metabolic disorders, cardiovascular disease, and various malignancies, that have been associated with GalNAc-Ts through genome-wide association studies and other linkage studies [16-26]. Therefore, it is imperative that we establish how O-glycosylation at specific sites in proteins affects protein function. A major task in achieving this goal is to identify the non-redundant biological functions of site-specific O-glycosylation. We and others recently developed new strategies for identifying specific sites on proteins that undergo O-glycosylation in different cell types and tissues [27-31]. Characterization of the O-glycoproteomic landscape in isolated human cells and multiple human cell lines suggests that more than 80 % of all proteins that traffic through the secretory pathway are O-glycoproteins [28, 30]. Probing the non-redundant contributions of individual GalNAc-Ts in cells with and without specific GalNAc-Ts [32-34] has revealed broad substrate specificities for some of the individual isoforms, whereas others seem to have very restricted substrate specificities [33-35]. Assessing all of the mapped O-glycosylation sites to identify associations between O-glycosites and protein annotations, we recently found that O-glycans are over-represented close to tandem repeat regions, protease cleavage sites, within propeptides, and on a select group of protein domains [28, 30, 36]. Although such general associations between the location of O-glycans and protein functions may direct future investigations, the strategy does not define the function of site-specific glycosylation. Further progress in discovering and defining novel functions of site-specific glycosylation events requires direct quantitative analysis of potential biological responses induced by the loss of distinct GalNAc-T isoforms, and such biological responses are not easily observed in single cell culture systems. Instead, more complex model systems can be used to examine and dissect the molecular mechanisms underlying the important biological functions of site-specific glycosylation. We previously used an organotypic tissue model equipped with genetically engineered cells to decipher the function of elongated O-glycans [29]. In the present study, we use the model combined with quantitative O-glycoproteomics and phosphoproteomics to perform open-ended discovery of the biological functions of site-specific glycosylation governed by GalNAc-Ts (Fig 1B). With this combinatorial strategy, we demonstrate that loss of individual GalNAc-T isoforms has distinct phenotypic consequences through their effect on distinct biological pathways, suggesting specific roles during epithelial formation.
2020-05-22 | PXD016618 | Pride
Project description:Site-specific N-glycosylation characterization requires intact N-glycopeptide analysis based on suitable tandem mass spectrometry (MS/MS) method. Electron-transfer/higher-energy collisional dissociation (EThcD), stepped collision energy/higher-energy collisional dissociation (sceHCD), and higher-energy collision dissociation-product-dependent electron-transfer dissociation (HCD-pd-ETD) have emerged as valuable approaches for clinical glycoproteomics. However, each of them incurs some compromise, necessitating the performance comparisons when applied to the analysis of complex clinical samples (e.g., plasma, urine, cells, and tissue). Herein, we developed a hybrid mass spectrometry fragmentation method, EThcD-sceHCD, by combining EThcD and sceHCD. Moreover, we compared the performance of this method with those previous approaches (EThcD, sceHCD, HCD-pd-ETD, and sceHCD-pd-ETD) in the intact N-glycopeptide analysis, and determined its applicability for clinical N-glycoproteomic study.
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2021-09-09 | PXD018418 | Pride
Project description:Dr. Clausen's laboratory is interested in the structure, biosynthesis and genetic regulation of glycoconjugates, with a major focus on mucins. This laboratory is studying the glycosylation and secretion process of mucins and biological functions involving mucins. This lab is also interested in receptor modulation mediated by glycosylation or through glycosphingolipids. RNA samples from two human pancreatic cell lines. The relevance of the variable expression levels of isoforms belonging to the polypeptide GalNAc-transferase gene-family is still a puzzle to us. The polypeptide GalNAc-transferase gene family is estimated to contain 24 gene-members all participating in the initiation of mucin-type O-glycosylation. It has become apparent that each of these individual isoforms have different tissue distribution profiles and kinetic capabilities. Mucin-type O-glycosylation is thus controlled, and dependent upon the repetoir of expressed GalNAc-transferases in any given organ and cell type at any given time. We have been trying to contribute to the understanding of the ordered process controlling mucin-type O-glycosylation in both normal and malignant models, and are currently investigating a pancreatic cell line model in the lab. The pancreatic tumor cell line ASPC-1 has been found to possess low metastatic potential in mouse models, in contrast to the pancreatic tumor cell line Suit-T2 possessing high metastatic potential. Immunohistochemical analysis of both cell lines, ASPC-1 and Suit-T2, using our monoclonal antibodies to 7 isoforms has revealed great differences in the expression profile of these 7 isoforms in theses two cell lines, and for instance GalNAc-T3 has been found to be highly expressed in Suit-T2 but completely lacking in ASPC-1.
2010-12-11 | GSE26011 | GEO
Project description:The densely glycosylated spike (S) proteins that are highly exposed on the surface of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) facilitate viral attachment, entry, and membrane fusion. We have previously reported all the 22 N-glycosites and site-specific N-glycans in the S protein protomer. Herein, we report the comprehensive site-specific O-glycosylation landscapes of SARS-CoV-2 S proteins, which were characterized using high-resolution mass spectrometry. Following digestion using trypsin and trypsin/Glu-C, and de-N-glycosylation using PNGase F, we determined the mucin-type (GalNAc-type) O-glycosylation pattern of S proteins, including O-glycosites and the 6 most common O-glycans occupying them, via Byonic identification and manual validation. Finally, 43 O-glycosites were identified by higher energy collision-induced dissociation (HCD), and 11 O-glycosites were verified by electron transfer/higher energy collision-induced dissociation (EThcD) in the insect cell-expressed S protein. Most glycosites were modified by non-sialylated O-glycans such as HexNAc(1) and HexNAc(1)Hex(1). In contrast, 30 O-glycosites were identified by HCD, and 14 O-glycosites were verified by EThcD in the human cell-expressed S protein S1 subunit. Most glycosites were modified by sialylated O-glycans such as HexNAc(1)Hex(1)NeuAc(1) and HexNAc(1)Hex(1)NeuAc(2). Our results are the first to reveal that the SARS-CoV-2 S protein is a mucin-type glycoprotein; clustered O-glycans often occur in the N- and the C-termini of the S protein, and the O-glycosite and O-glycan compositions vary with the host cell type. These site-specific O-glycosylation landscapes of the SARS-CoV-2 S protein are expected to provide novel insights into the viral binding mechanism and present a strategy for the development of vaccines and targeted drugs.
2021-11-03 | PXD022896 | Pride
Project description:Bioorthogonal chemistries have revolutionized many fields. For example, metabolic chemical reporters (MCRs) of glycosylation are analogs of monosaccharides that contain bioorthogonal functionality, like azides or alkynes. MCRs are metabolically incorporated into glycoproteins by living systems, and bioorthogonal reactions can be subsequently employed to install visualization and enrichment tags. Unfortunately, most MCRs are not selective for one class of glycosylation (e.g. N-linked vs. O-linked), complicating the types of information that can be gleaned. We and others have successfully created MCRs that are selective for intracellular O-GlcNAc modification by altering the structure of the MCR and thus biasing it to certain metabolic pathways and/or O-GlcNAc transferase (OGT). Here, we attempt to do the same for the core GalNAc residue of mucin O-linked glycosylation. The most widely applied MCR for mucin O-linked glycosylation, GalNAz, can be enzymatically epimerized at the 4-hydroxyl to give GlcNAz. This results in a mixture of cell-surface and O-GlcNAc labeling. We reasoned that replacing the 4-hydroxyl of GalNAz with a fluorine would lock the stereochemistry of this position in place, causing the MCR to be more selective. After synthesis, we found that 4FGalNAz labels a variety of proteins in mammalian cells and does not perturb endogenous glycosylation pathways unlike 4FGalNAc. However, through subsequent proteomic and biochemical characterization we found that 4FGalNAz does not widely label cell-surface glycoproteins but instead is primarily a substrate for OGT. Although these results are somewhat disappointing from the standpoint of a mucin-selective MCR, they once again highlight the large substrate flexibility of OGT, with interesting and important implications for intracellular protein modification by a potential range of abiotic and native monosaccharides.
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