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Nature Reviews. Rheumatology Jan 2023Glycosylation has a profound influence on protein activity and cell biology through a variety of mechanisms, such as protein stability, receptor interactions and signal... (Review)
Review
Glycosylation has a profound influence on protein activity and cell biology through a variety of mechanisms, such as protein stability, receptor interactions and signal transduction. In many rheumatic diseases, a shift in protein glycosylation occurs, and is associated with inflammatory processes and disease progression. For example, the Fc-glycan composition on (auto)antibodies is associated with disease activity, and the presence of additional glycans in the antigen-binding domains of some autoreactive B cell receptors can affect B cell activation. In addition, changes in synovial fibroblast cell-surface glycosylation can alter the synovial microenvironment and are associated with an altered inflammatory state and disease activity in rheumatoid arthritis. The development of our understanding of the role of glycosylation of plasma proteins (particularly (auto)antibodies), cells and tissues in rheumatic pathological conditions suggests that glycosylation-based interventions could be used in the treatment of these diseases.
Topics: Humans; Glycomics; Glycosylation; Rheumatic Diseases; Arthritis, Rheumatoid
PubMed: 36418483
DOI: 10.1038/s41584-022-00867-4 -
Genes Apr 2023The hexosamine biosynthesis pathway (HBP) produces uridine diphosphate--acetyl glucosamine, UDP-GlcNAc, which is a key metabolite that is used for - or -linked... (Review)
Review
The hexosamine biosynthesis pathway (HBP) produces uridine diphosphate--acetyl glucosamine, UDP-GlcNAc, which is a key metabolite that is used for - or -linked glycosylation, a co- or post-translational modification, respectively, that modulates protein activity and expression. The production of hexosamines can occur via de novo or salvage mechanisms that are catalyzed by metabolic enzymes. Nutrients including glutamine, glucose, acetyl-CoA, and UTP are utilized by the HBP. Together with availability of these nutrients, signaling molecules that respond to environmental signals, such as mTOR, AMPK, and stress-regulated transcription factors, modulate the HBP. This review discusses the regulation of GFAT, the key enzyme of the de novo HBP, as well as other metabolic enzymes that catalyze the reactions to produce UDP-GlcNAc. We also examine the contribution of the salvage mechanisms in the HBP and how dietary supplementation of the salvage metabolites glucosamine and -acetylglucosamine could reprogram metabolism and have therapeutic potential. We elaborate on how UDP-GlcNAc is utilized for -glycosylation of membrane and secretory proteins and how the HBP is reprogrammed during nutrient fluctuations to maintain proteostasis. We also consider how -GlcNAcylation is coupled to nutrient availability and how this modification modulates cell signaling. We summarize how deregulation of protein -glycosylation and -GlcNAcylation can lead to diseases including cancer, diabetes, immunodeficiencies, and congenital disorders of glycosylation. We review the current pharmacological strategies to inhibit GFAT and other enzymes involved in the HBP or glycosylation and how engineered prodrugs could have better therapeutic efficacy for the treatment of diseases related to HBP deregulation.
Topics: Hexosamines; Protein Processing, Post-Translational; Glucosamine; Glycosylation; TOR Serine-Threonine Kinases
PubMed: 37107691
DOI: 10.3390/genes14040933 -
Advances in understanding N-glycosylation structure, function, and regulation in health and disease.European Journal of Cell Biology 2021N-linked glycosylation is a post-translational modification crucial for membrane protein folding, stability and other cellular functions. Alteration of membrane protein... (Review)
Review
N-linked glycosylation is a post-translational modification crucial for membrane protein folding, stability and other cellular functions. Alteration of membrane protein N-glycans is implicated in wide range of pathological conditions including cancer metastasis, chronic inflammatory diseases, and viral pathogenesis. Even though the roles of N-glycans have been studied extensively, our knowledge of their mechanisms remains unclear due to the lack of detailed structural analysis of the N-glycome. Mapping the N-glycome landscape will open new avenues to explore disease mechanisms and identify novel therapeutic targets. This review discusses the diverse structure of N-linked glycans, the function and regulation of N-glycosylation in health and disease, and ends with a focus on recent approaches to target N-glycans in rheumatoid arthritis and cancer metastasis.
Topics: Glycosylation; Polysaccharides; Protein Processing, Post-Translational
PubMed: 34839178
DOI: 10.1016/j.ejcb.2021.151186 -
Cell Death and Differentiation Aug 2023Pancreatic ductal adenocarcinoma (PDAC) remains a highly fatal malignancy partially due to the acquired alterations related to aberrant protein glycosylation that...
Pancreatic ductal adenocarcinoma (PDAC) remains a highly fatal malignancy partially due to the acquired alterations related to aberrant protein glycosylation that pathologically remodel molecular biological processes and protect PDAC cells from death. Ferroptosis driven by lethal lipid peroxidation provides a targetable vulnerability for PDAC. However, the crosstalk between glycosylation and ferroptosis remains unclear. Here, we identified 4F2hc, a subunit of the glutamate-cystine antiporter system X, and its asparagine (N)-glycosylation is involved in PDAC ferroptosis by N- and O-linked glycoproteomics. Knockdown of SLC3A2 (gene name of 4F2hc) or blocking the N-glycosylation of 4F2hc potentiates ferroptosis sensitization of PDAC cells by impairing the activity of system X manifested by a marked decrease in intracellular glutathione. Mechanistically, we found that the glycosyltransferase B3GNT3 catalyzes the glycosylation of 4F2hc, stabilizes the 4F2hc protein, and enhances the interaction between 4F2hc and xCT. Knockout of B3GNT3 or deletion of enzymatically active B3GNT3 sensitizes PDAC cells to ferroptosis. Reconstitution of 4F2hc-deficient cells with wildtype 4F2hc restores ferroptosis resistance while glycosylation-mutated 4F2hc does not. Additionally, upon combination with a ferroptosis inducer, treatment with the classical N-glycosylation inhibitor tunicamycin (TM) markedly triggers the overactivation of lipid peroxidation and enhances the sensitivity of PDAC cells to ferroptosis. Notably, we confirmed that genetic perturbation of SLC3A2 or combination treatment with TM significantly augments ferroptosis-induced inhibition of orthotopic PDAC. Clinically, high expression of 4F2hc and B3GNT3 contributes to the progression and poor survival of PDAC patients. Collectively, our findings reveal a previously unappreciated function of N-glycosylation of 4F2hc in ferroptosis and suggest that dual targeting the vulnerabilities of N-glycosylation and ferroptosis may be an innovative therapeutic strategy for PDAC.
Topics: Humans; Glycosylation; Ferroptosis; Glycosyltransferases; Cell Line, Tumor; Pancreatic Neoplasms; Carcinoma, Pancreatic Ductal; N-Acetylglucosaminyltransferases
PubMed: 37479744
DOI: 10.1038/s41418-023-01188-z -
Current Opinion in Structural Biology Dec 2022
Topics: Glycosylation; Carbohydrates
PubMed: 36179500
DOI: 10.1016/j.sbi.2022.102468 -
International Journal of Molecular... May 2023Heart failure (HF) is a progressive chronic disease that remains a primary cause of death worldwide, affecting over 64 million patients. HF can be caused by... (Review)
Review
Heart failure (HF) is a progressive chronic disease that remains a primary cause of death worldwide, affecting over 64 million patients. HF can be caused by cardiomyopathies and congenital cardiac defects with monogenic etiology. The number of genes and monogenic disorders linked to development of cardiac defects is constantly growing and includes inherited metabolic disorders (IMDs). Several IMDs affecting various metabolic pathways have been reported presenting cardiomyopathies and cardiac defects. Considering the pivotal role of sugar metabolism in cardiac tissue, including energy production, nucleic acid synthesis and glycosylation, it is not surprising that an increasing number of IMDs linked to carbohydrate metabolism are described with cardiac manifestations. In this systematic review, we offer a comprehensive overview of IMDs linked to carbohydrate metabolism presenting that present with cardiomyopathies, arrhythmogenic disorders and/or structural cardiac defects. We identified 58 IMDs presenting with cardiac complications: 3 defects of sugar/sugar-linked transporters (GLUT3, GLUT10, THTR1); 2 disorders of the pentose phosphate pathway (G6PDH, TALDO); 9 diseases of glycogen metabolism (GAA, GBE1, GDE, GYG1, GYS1, LAMP2, RBCK1, PRKAG2, G6PT1); 29 congenital disorders of glycosylation (ALG3, ALG6, ALG9, ALG12, ATP6V1A, ATP6V1E1, B3GALTL, B3GAT3, COG1, COG7, DOLK, DPM3, FKRP, FKTN, GMPPB, MPDU1, NPL, PGM1, PIGA, PIGL, PIGN, PIGO, PIGT, PIGV, PMM2, POMT1, POMT2, SRD5A3, XYLT2); 15 carbohydrate-linked lysosomal storage diseases (CTSA, GBA1, GLA, GLB1, HEXB, IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, ARSB, GUSB, ARSK). With this systematic review we aim to raise awareness about the cardiac presentations in carbohydrate-linked IMDs and draw attention to carbohydrate-linked pathogenic mechanisms that may underlie cardiac complications.
Topics: Humans; Cardiomyopathies; Metabolic Diseases; Heart Defects, Congenital; Glycosylation; Carbohydrates; Sugars; Chondroitinsulfatases; Pentosyltransferases; Mannosyltransferases; Acetyltransferases
PubMed: 37239976
DOI: 10.3390/ijms24108632 -
Current Opinion in Structural Biology Aug 2022The structure and post-translational processing of the SARS-CoV-2 spike glycoprotein (S) is intimately associated with the function of the virus and of sterilising... (Review)
Review
The structure and post-translational processing of the SARS-CoV-2 spike glycoprotein (S) is intimately associated with the function of the virus and of sterilising vaccines. The surface of the S protein is extensively modified by glycans, and their biosynthesis is driven by both the wider cellular context, and importantly, the underlining protein structure and local glycan density. Comparison of virally derived S protein with both recombinantly derived and adenovirally induced proteins, reveal hotspots of protein-directed glycosylation that drive conserved glycosylation motifs. Molecular dynamics simulations revealed that, while the S surface is extensively shielded by N-glycans, it presents regions vulnerable to neutralising antibodies. Furthermore, glycans have been shown to influence the accessibility of the receptor binding domain and the binding to the cellular receptor. The emerging picture is one of unifying, principles of S protein glycosylation and an intimate role of glycosylation in immunogen structure and efficacy.
Topics: COVID-19; Glycosylation; Humans; Polysaccharides; Protein Binding; SARS-CoV-2
PubMed: 35717706
DOI: 10.1016/j.sbi.2022.102402 -
International Journal of Molecular... Aug 2020N-glycans are covalently linked to an asparagine residue in a simple acceptor sequence of proteins, called a sequon. This modification is important for protein folding,... (Review)
Review
N-glycans are covalently linked to an asparagine residue in a simple acceptor sequence of proteins, called a sequon. This modification is important for protein folding, enhancing thermodynamic stability, and decreasing abnormal protein aggregation within the endoplasmic reticulum (ER), for the lifetime and for the subcellular localization of proteins besides other functions. Hypoglycosylation is the hallmark of a group of rare genetic diseases called congenital disorders of glycosylation (CDG). These diseases are due to defects in glycan synthesis, processing, and attachment to proteins and lipids, thereby modifying signaling functions and metabolic pathways. Defects in N-glycosylation and O-glycosylation constitute the largest CDG groups. Clotting and anticlotting factor defects as well as a tendency to thrombosis or bleeding have been described in CDG patients. However, N-glycosylation of platelet proteins has been poorly investigated in CDG. In this review, we highlight normal and deficient N-glycosylation of platelet-derived molecules and discuss the involvement of platelets in the congenital disorders of N-glycosylation.
Topics: Animals; Blood Platelets; Calcium; Energy Metabolism; Glycosylation; Homeostasis; Humans; Models, Biological
PubMed: 32781578
DOI: 10.3390/ijms21165630 -
International Journal of Molecular... May 2021How millions of axons navigate accurately toward synaptic targets during development is a long-standing question. Over decades, multiple studies have enriched our... (Review)
Review
How millions of axons navigate accurately toward synaptic targets during development is a long-standing question. Over decades, multiple studies have enriched our understanding of axonal pathfinding with discoveries of guidance molecules and morphogens, their receptors, and downstream signalling mechanisms. Interestingly, classification of attractive and repulsive cues can be fluid, as single guidance cues can act as both. Similarly, guidance cues can be secreted, chemotactic cues or anchored, adhesive cues. How a limited set of guidance cues generate the diversity of axonal guidance responses is not completely understood. Differential expression and surface localization of receptors, as well as crosstalk and spatiotemporal patterning of guidance cues, are extensively studied mechanisms that diversify axon guidance pathways. Posttranslational modification is a common, yet understudied mechanism of diversifying protein functions. Many proteins in axonal guidance pathways are glycoproteins and how glycosylation modulates their function to regulate axonal motility and guidance is an emerging field. In this review, we discuss major classes of glycosylation and their functions in axonal pathfinding. The glycosylation of guidance cues and guidance receptors and their functional implications in axonal outgrowth and pathfinding are discussed. New insights into current challenges and future perspectives of glycosylation pathways in neuronal development are discussed.
Topics: Animals; Axons; Glycoproteins; Glycosylation; Humans; Nerve Growth Factors; Signal Transduction
PubMed: 34068002
DOI: 10.3390/ijms22105143 -
Nature Communications Jun 2023Sialic acid-binding Ig-like lectin 15 (Siglec-15) is an immune modulator and emerging cancer immunotherapy target. However, limited understanding of its structure and...
Sialic acid-binding Ig-like lectin 15 (Siglec-15) is an immune modulator and emerging cancer immunotherapy target. However, limited understanding of its structure and mechanism of action restrains the development of drug candidates that unleash its full therapeutic potential. In this study, we elucidate the crystal structure of Siglec-15 and its binding epitope via co-crystallization with an anti-Siglec-15 blocking antibody. Using saturation transfer-difference nuclear magnetic resonance (STD-NMR) spectroscopy and molecular dynamics simulations, we reveal Siglec-15 binding mode to α(2,3)- and α(2,6)-linked sialic acids and the cancer-associated sialyl-Tn (STn) glycoform. We demonstrate that binding of Siglec-15 to T cells, which lack STn expression, depends on the presence of α(2,3)- and α(2,6)-linked sialoglycans. Furthermore, we identify the leukocyte integrin CD11b as a Siglec-15 binding partner on human T cells. Collectively, our findings provide an integrated understanding of the structural features of Siglec-15 and emphasize glycosylation as a crucial factor in controlling T cell responses.
Topics: Humans; Crystallization; Epitopes; Glycosylation; Integrins; T-Lymphocytes
PubMed: 37311743
DOI: 10.1038/s41467-023-39119-8