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Glycans commonly found on cell surface receptors. The extracellular domains of receptors are glycosylated, and specific glycans have been shown to either block or activate receptor dimerization or activation. Virtually all receptors have multiple N-glycans that include oligomannose, complex or bisected structures. Fucose bound to the N-glycan core or to N-acetyllactosamine chains and sialic acid are among the terminal sugar residues. Some receptors have O-glycans that are commonly comprised of simple GalNAc (Tn antigen), core 1 (T antigen) and sialyl-T antigen structures. Not all possible glycosylation sites are occupied and the role of these glycans may vary between occupied sites, cell types and the specific receptors.
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Cells undergo proliferation and apoptosis, migration and differentiation via a number of cell surface receptors, most of which are heavily glycosylated. This review discusses receptor glycosylation and the known roles of glycans on the functions of receptors expressed in diverse cell types. We included growth factor receptors that have an intracell...
Context in source publication
Context 1
... receptors initiate signal transduction utilizing shared intracellular proteases, kinases and transcription factors that regulate cellular survival, cell death, migration and many other biological phenomena. Many receptors, as well as the glycosyltransferases (GTs) that glycosylate proteins, are expressed in a cell-type-specific fashion, thus producing a heteroge- Figure 1. Glycans commonly found on cell surface receptors. ...
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Citations
... Mammalian cells are covered with a dense layer of glycans and the proteins and lipids they are attached to, termed the glycocalyx, which is involved in various vital cellular processes [4][5][6] . The type, size, structure, and charge of cell surface glycans may affect the biological properties of the cells and their susceptibility to potential viral infections 2,4,7 . Mammalian glycoconjugates, located on the cell membrane and extra-or intracellular space, play crucial roles in physiological and pathological events 2,4,5,7,8 . ...
... The type, size, structure, and charge of cell surface glycans may affect the biological properties of the cells and their susceptibility to potential viral infections 2,4,7 . Mammalian glycoconjugates, located on the cell membrane and extra-or intracellular space, play crucial roles in physiological and pathological events 2,4,5,7,8 . Alterations in the glycomic profiles of glycoproteins, e.g., overexpression of sialylated or core fucosylated glycans, or increased levels of complex-type branched glycans, may promote the acquisition of cellular features required for the malignant transformation of cells 1,[9][10][11][12] . ...
... Glycosylation abnormalities represent an overt source of potential biomarkers for the diagnostic, prognostic, and treatment monitoring of various human diseases, including autoimmune, congenital, oncological, and neurodegenerative pathologies 5,7,12 . In the emerging field of glycomedicine, novel therapeutic drugs or vaccines targeting tumor-associated carbohydrate antigens, like Lewis antigens and polysialic acids, are also currently in clinical evaluation 5,15,16 . ...
The development of reliable single-cell dispensers and substantial sensitivity improvement in mass spectrometry made proteomic profiling of individual cells achievable. Yet, there are no established methods for single-cell glycome analysis due to the inability to amplify glycans and sample losses associated with sample processing and glycan labeling. In this work, we present an integrated platform coupling online in-capillary sample processing with high-sensitivity label-free capillary electrophoresis-mass spectrometry for N-glycan profiling of single mammalian cells. Direct and unbiased quantitative characterization of single-cell surface N-glycomes are demonstrated for HeLa and U87 cells, with the detection of up to 100 N-glycans per single cell. Interestingly, N-glycome alterations are unequivocally detected at the single-cell level in HeLa and U87 cells stimulated with lipopolysaccharide. The developed workflow is also applied to the profiling of ng-level amounts (5–500 ng) of blood-derived protein, extracellular vesicle, and total plasma isolates, resulting in over 170, 220, and 370 quantitated N-glycans, respectively.
... Поверхностные рецепторы представляют собой белок, наружная часть которого способна распознавать специальные сигнальные молекулы, инициирующие апоптоз. Естесственным лигандом для Fas-рецепторов служит мембранный белок II типа Fas-L со значительной гомологией с TNF-α [18,27,34,39]. Результаты проведенного исследования не противоречили современным теоретическим представлениям. ...
The objective was to predict the fatal outcome of the disease in newborns on artificial lung ventilation by means of an intelligent analysis of the immunological database.
Materials and methods . The retrospective clinical study included 108 mature newborns. Upon admission to the intensive care unit, on the 3rdday and at the end of the disease, the plasma concentrations of IL-1β, IL-6, IL-8, TNF-α, G-CSF, s-Fas, FGF, NO were determined by ELISA; the relative content of CD3 ⁺ CD19 – , CD3 – CD19 ⁺ , CD3 ⁺ CD4 ⁺ , CD3 ⁺ CD8 ⁺ , CD69 ⁺ , CD71 ⁺ , CD95 ⁺ , HLA-DR ⁺ , CD34 ⁺ ; CD14 ⁺ , CD3–CD56 ⁺ by immunophenotyping; relative content of lymphocytes with expression of AnnexinV-FITC ⁺ PI – , AnnexinV-FITC ⁺ PI ⁺ . By the method of decision trees, the rule of predicting death was formulated.
Results . The patient is predicted fatal outcome if, upon admission to intensive care, he has the relative content of lymphocytes with expression of AnnexinV-FITC ⁺ PI ⁺ ≥ 0.95 % and plasma concentration of G-CSF ≤ 1.46 pg\ml or G-CSF ≥ 1.46 pg\ml and AnnexinV-FITC ⁺ PI ⁺ ≥ 4.75 %(specificity 98.68 %; sensitivity 96.97 %; accuracy 98.68 %).
Conclusion . In newborns with respiratory pathology and perinatal involvement of the central nervous system on artificial ventilation, death is determined by the high activity of T-lymphocyte apoptosis mediated by the low plasma concentration of granulocyte colony stimulating factor.
... A4gnt encodes a glycotransferase that transfers N-acetylglucosamine (GlcNAc) to O-glycans. While A4gnt is primarily known to have activity in the gastrointestinal system, O-glycans are important for cell signaling pathways and induction of apoptosis in stem cells (Gao et al., 2021;Nishihara, 2018). The most increased genes in females versus males were Esr2 (+6.9 Log2FC), Ly6g6c (+6.4 Log2FC), and Trim66 (+4.8 Log2FC). ...
Background
Prenatal alcohol exposure during gastrulation (embryonic day [E] 7 in mice, ~3rd week of human pregnancy) impairs eye, facial, and cortical development, recapitulating birth defects characteristic of Fetal Alcohol Syndrome (FAS). However, it is not known whether the prevalence or severity of craniofacial features associated with FAS is affected by biological sex.
Methods
The current study administered either alcohol (2.9 g/kg, two i.p. doses, 4 hr apart) or vehicle to pregnant C57BL/6J females on E7, prior to gonadal sex differentiation, and assessed fetal morphology at E17.
Results
Whereas sex did not affect fetal size in controls, alcohol‐exposed females were smaller than both control females and alcohol‐treated males. Alcohol exposure increased the incidence of eye defects to a similar degree in males and females. Together, these data suggest that females might be more sensitive to the general developmental effects of alcohol, but not effects specific to the craniofacies. Whole transcriptomic analysis of untreated E7 embryos found 214 differentially expressed genes in females vs. males, including those in pathways related to cilia and mitochondria, histone demethylase activity, and pluripotency.
Conclusion
Gastrulation‐stage alcohol induces craniofacial malformations in male and female mouse fetuses at similar rates and severity, though growth deficits are more prevalent females. These findings support the investigation of biological sex as a contributing factor in prenatal alcohol studies.
... 3 Glycans attached to membrane-bound receptors not only profoundly inuence their physicochemical properties, such as solubility, stability and folding, but they also impact various cellular functions including ligand binding, oligomerization and signaling pathways. [4][5][6][7][8] Previous studies have shown that aberrant protein glycosylation is closely associated with a wide range of diseases, particularly cancer. 3,[9][10][11][12] The epidermal growth factor receptor (EGFR) is a typical single transmembrane glycoprotein that plays a crucial role in cell proliferation, differentiation and survival. ...
The epidermal growth factor receptor (EGFR) is a cell-surface glycoprotein that is involved mainly in cell proliferation. Overexpression of this receptor is intimately related to the development of a broad spectrum of tumors. In addition, glycans linked to the EGFR are known to affect its EGF-induced activation. Because of the pathophysiological significance of the EGFR, we prepared a fluorescently labeled EGFR (EGFR128-AZDye 488) on the cell surface by employing the genetic code expansion technique and bioorthogonal chemistry. EGFR128-AZDye 488 was initially utilized to investigate time-dependent endocytosis of the EGFR in live cells. The results showed that an EGFR inhibitor and antibody suppress endocytosis of the EGFR promoted by the EGF, and that lectins recognizing glycans of the EGFR do not enhance EGFR internalization into cells. Observations made in studies of the effects of appended glycans on the entry of the EGFR into cells indicate that a de-sialylated or de-fucosylated EGFR is internalized into cells more efficiently than a wild-type EGFR. Furthermore, by using the FRET-based imaging method of cells which contain an EGFR linked to AZDye 488 (a FRET donor) and cellular glycans labeled with rhodamine (a FRET acceptor), sialic acid residues attached to the EGFR were specifically detected on the live cell surface. Taken together, the results suggest that a fluorescently labeled EGFR will be a valuable tool in studies aimed at gaining an understanding of cellular functions of the EGFR.
... Interestingly, and as expected, IgM and IgG immunoglobulins, and total plasma and plasma-derived EVs were clustered in two distinct clades, based on their respective Nglycome pro les (Fig. 2J). 68 N-glycans were uniquely detected in human serum IgM ( Figure S1), among which 25% were highly fucosylated (i.e., 5-7 fucose residues) and 10% were highly sialylated (i.e., [5][6][7][8][9][10][11] SiA residues) N-glycans. 185 N-glycans were uniquely detected in total human plasma ( Figure S1), among which 12% were highly fucosylated (i.e., 5-7 fucose residues) and 31% were highly sialylated (i.e., ...
The development of reliable single-cell dispensers and substantial sensitivity improvement in mass spectrometry made proteomic profiling of individual cells achievable. Yet, there are no established methods for single-cell glycome analysis due to the inability to amplify glycans and sample losses associated with sample processing and glycan labeling. In this work, we developed an integrated platform coupling online in-capillary sample processing with high-sensitivity label-free capillary electrophoresis-mass spectrometry for N-glycan profiling of single mammalian cells. Direct and unbiased characterization and quantification of single-cell surface N-glycomes were demonstrated for HeLa and U87 cells, with the detection of up to 100 N-glycans per single cell. Interestingly, N-glycome alterations were unequivocally detected at the single-cell level in HeLa and U87 cells stimulated with lipopolysaccharide. The developed workflow was also applied to the profiling of ng-level amounts of blood-derived protein, extracellular vesicle, and total plasma isolates, resulting in over 170, 220, and 370 quantitated N-glycans, respectively.
... Growth factors engage cell surface receptors and trigger signaling events with wide cellular ramifications (Avraham and Yarden, 2011;Lemmon and Schlessinger, 2010), including 20 effects on the glycosylation machinery and the glycosylation state of de novo synthesized proteins (Gao et al., 2021;Gilmour et al., 2013;Marsico et al., 2018;Palmisano et al., 2011;Stanley, 2011;Takahashi et al., 2016;Zhao et al., 2008). The possibility that growth factors affect glycans at the plasma membrane has been largely overlooked. ...
It is commonly assumed that the glycan makeup of glycoproteins that reach the cell surface is final and static. Here, we challenge this notion by the discovery of a molecular switch that induces acute and reversible changes of glycans on the plasma membrane. We demonstrate that within minutes, the epidermal growth factor triggers the galectin-driven endocytosis of cell surface glycoproteins, such as integrins, that are key regulators of cell adhesion and migration. The onset of this process, mediated by the Na+/H+ antiporter NHE-1 and the neuraminidases Neu1/3, requires the pH-triggered enzymatic removal of sialic acids whose presence otherwise prevents galectin binding. Desialylated glycoproteins are then retrogradely transported to the Golgi apparatus where their glycan makeup is reset, and their function is repurposed to regulate EGF-dependent invasive cell migration. Glycosylation at the cell surface thereby emerges as a dynamic and reversible regulatory post-translational modification that controls a highly adaptable trafficking pathway.
... Nand O-glycosylation, O-GlcNAcylation, and phosphorylation are the most common modifications that increase protein solubility, conformation, interactions, signaling, and degradation, which are all critical for cell growth [26]. Nand O-glycosylation facilitates receptor binding and alters the structure of the secreted proteins [27,28]. In contrast, O-GlcNAcylation and phosphorylation are competitive processes implicated in many signal transduction pathways [29,30]. ...
Norovirus is the most common cause of foodborne gastroenteritis, affecting millions of people worldwide annually. Among the ten genotypes (GI–GX) of norovirus, only GI, GII, GIV, GVIII, and GIX infect humans. Some genotypes reportedly exhibit post-translational modifications (PTMs), including N- and O-glycosylation, O-GlcNAcylation, and phosphorylation, in their viral antigens. PTMs have been linked to increased viral genome replication, viral particle release, and virulence. Owing to breakthroughs in mass spectrometry (MS) technologies, more PTMs have been discovered in recent years and have contributed significantly to preventing and treating infectious diseases. However, the mechanisms by which PTMs act on noroviruses remain poorly understood. In this section, we outline the current knowledge of the three common types of PTM and investigate their impact on norovirus pathogenesis. Moreover, we summarize the strategies and techniques for the identification of PTMs.
... Unlike the peptide bonds, the glycosidic bonds are flexible, which allows the protein to sample a wider range of conformations than previously observed 10 . Hence, they alter many aspects of the protein such as its stability, function, interactions, assembly, oligomerization states 11,12 with a well-documented example being G-protein coupled receptors 13 . One instance of physical enhancement reported in hCD2ad 14 increases stability and solubility. ...
The unique viviparous Pacific Beetle cockroaches provide nutrition to their embryo by secreting milk proteins Lili-Mip, which is a lipid-binding glycoprotein that crystallizes in vivo. The resolved in vivo crystal structure of variably glycosylated Lili-Mip shows a classical Lipocalin fold with an eight-stranded antiparallel beta-barrel enclosing a fatty acid. The availability of physiologically unaltered glycoprotein structure makes Lili-Mip a very attractive model system to investigate the role of glycans on protein structure, dynamics, and function. Towards that end, we have employed all-atom molecular dynamics simulations on various glycosylated stages of a bound and free Lili-Mip protein and characterized the impact of glycans and the bound lipid on the dynamics of this glycoconjugate. Our work provides important molecular-level mechanistic insights into the role of glycans in the nutrient storage function of the Lili-Mip protein. Our analyses show that the glycans locally stabilize spatially proximal residues and regulate the low amplitude opening motions of the residues at the entrance of the binding pocket. Glycans, which are located at the portal end of the barrel, also restrict the distal barrel depth and allosterically modulate the lipid dynamics in the barrel. A simple but effective distance-based network analysis of the protein also reveals the role of glycans in the subtle rewiring of residues crucial for determining the barrel depth and lipid orientation.
... The rTBL-1 localization in the membrane surface without EGFR signal was also noted, suggesting that other surface molecules may be involved in the cellular interactions of rTBL-1. EGFR is an important glycoprotein for cancer biology with a significant number of glycosylation sites (7-13 N-glycosylations in the extracellular domain); it is highly expressed in different cancers and is considered a proteomic marker [76][77][78][79]. In addition, EGFR-specific N-glycosylations are correlated with the disease state/progression of colorectal cancer [80], thus, EGFR-related N-glycans were considered for the docking process. ...
Previous works showed that a Tepary bean lectin fraction (TBLF) induced apoptosis on colon cancer cells and inhibited early colonic tumorigenesis. One Tepary bean (TB) lectin was expressed in Pichia pastoris (rTBL-1), exhibiting similarities to one native lectin, where its molecular structure and in silico recognition of cancer-type N-glycoconjugates were confirmed. This work aimed to determine whether rTBL-1 retained its bioactive properties and if its apoptotic effect was related to EGFR pathways by studying its cytotoxic effect on colon cancer cells. Similar apoptotic effects of rTBL-1 with respect to TBLF were observed for cleaved PARP-1 and caspase 3, and cell cycle G0/G1 arrest and decreased S phase were observed for both treatments. Apoptosis induction on SW-480 cells was confirmed by testing HA2X, p53 phosphorylation, nuclear fragmentation, and apoptotic bodies. rTBL-1 increased EGFR phosphorylation but also its degradation by the lysosomal route. Phospho-p38 increased in a concentration- and time-dependent manner, matching apoptotic markers, and STAT1 showed activation after rTBL-1 treatment. The results show that part of the rTBL-1 mechanism of action is related to p38 MAPK signaling. Future work will focus further on the target molecules of this recombinant lectin against colon cancer.
... 38 Glycans in the binding site also control the accessibility of the binding site. 39 Binding site analysis and druggability assessment The geometry and physicochemical properties of the binding site are important in establishing the ability of the binding site to bind drug-like molecules. Descriptors that characterize geometry include volume, surface area as well as buriedness of the binding site. ...
Background: Nicastrin is a confirmed breast cancer target, but the lack of knowledge about its binding sites and the structural basis of interactions with known small molecules makes the development of small molecules against it challenging.
Methods: Molecular docking and molecular dynamics simulations were used in this work to identify binding sites in nicastrin, a gamma-secretase component that has been implicated in breast cancer and a potential drug target in cancer chemotherapy.
Results: Docking calculations identified three binding sites, however binding site analysis using druggability assessment identified a region that encompasses the DYIGS motif, the DYIGS site as the most favorable binding site. This site was validated by a 50 ns molecular dynamic simulation with a known inhibitor CID44433923 and free energy of binding was found to be -11.4 kcal/mol and mainly driven by hydrophobic interactions. Per residue decomposition analysis showed that Gln139, Val138 and Arg105 had a relatively high contribution towards the free energy of binding. These results suggest that these residues might be critical in nicastrin inhibition. Binding mode analysis by docking previously reported nicastrin inhibitors identified residues Gln139, Val138 and Asp143 as key in the interactions.
Conclusions: This work affords an insight into the binding mechanism of small molecules and might direct drug design efforts towards nicastrin.
