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EMBO Reports Nov 2023Fate determination of primordial germ cells (PGCs) is regulated in a multi-layered manner, involving signaling pathways, epigenetic mechanisms, and transcriptional...
Fate determination of primordial germ cells (PGCs) is regulated in a multi-layered manner, involving signaling pathways, epigenetic mechanisms, and transcriptional control. Chemical modification of macromolecules, including epigenetics, is expected to be closely related with metabolic mechanisms but the detailed molecular machinery linking these two layers remains poorly understood. Here, we show that the hexosamine biosynthetic pathway controls PGC fate determination via O-linked β-N-acetylglucosamine (O-GlcNAc) modification. Consistent with this model, reduction of carbohydrate metabolism via a maternal ketogenic diet that decreases O-GlcNAcylation levels causes repression of PGC formation in vivo. Moreover, maternal ketogenic diet intake until mid-gestation affects the number of ovarian germ cells in newborn pups. Taken together, we show that nutritional and metabolic mechanisms play a previously unappreciated role in PGC fate determination.
Topics: Infant, Newborn; Humans; Signal Transduction; Acetylglucosamine; Gene Expression Regulation; Epigenesis, Genetic; Germ Cells; Protein Processing, Post-Translational
PubMed: 37842859
DOI: 10.15252/embr.202356845 -
The Journal of Organic Chemistry Dec 2021We recently reported the incorporation of diazirine photo-cross-linkers onto the -GlcNAc posttranslational modification in mammalian cells, enabling the identification...
We recently reported the incorporation of diazirine photo-cross-linkers onto the -GlcNAc posttranslational modification in mammalian cells, enabling the identification of binding partners of -GlcNAcylated proteins. Unfortunately, the syntheses of the diazirine-functionalized substrates have exhibited inconsistent yields. We report a robust and stereoselective synthesis of cell-permeable GlcNAc-1-phosphate esters based on the use of commercially available bis(diisopropylamino)chlorophosphine. We demonstrate this approach for two diazirine-containing GlcNAc analogues, and we report the cellular incorporation of these compounds into glycoconjugates to support photo-cross-linking applications.
Topics: Acetylglucosamine; Animals; Diazomethane; Glycoconjugates; Phosphates; Proteins
PubMed: 34618463
DOI: 10.1021/acs.joc.1c01781 -
The Journal of Biological Chemistry Dec 2014O-Linked β-N-acetylglucosamine (O-GlcNAc) is a carbohydrate post-translational modification on hydroxyl groups of serine and/or threonine residues of cytosolic and... (Review)
Review
O-Linked β-N-acetylglucosamine (O-GlcNAc) is a carbohydrate post-translational modification on hydroxyl groups of serine and/or threonine residues of cytosolic and nuclear proteins. Analogous to phosphorylation, O-GlcNAcylation plays crucial regulatory roles in cellular signaling. Recent work indicates that increased O-GlcNAcylation is a general feature of cancer and contributes to transformed phenotypes. In this minireview, we discuss how hyper-O-GlcNAcylation may be linked to various hallmarks of cancer, including cancer cell proliferation, survival, invasion, and metastasis; energy metabolism; and epigenetics. We also discuss potential therapeutic modulation of O-GlcNAc levels in cancer treatment.
Topics: Acetylglucosamine; Animals; Carcinogenesis; Epigenesis, Genetic; Humans; Neoplasms; Neovascularization, Pathologic; Signal Transduction
PubMed: 25336642
DOI: 10.1074/jbc.R114.577718 -
Current Opinion in Chemical Biology Aug 2016O-GlcNAcylation is a dynamic post-translational modification that is responsive to nutrient availably via the hexosamine biosynthetic pathway and its endproduct... (Review)
Review
O-GlcNAcylation is a dynamic post-translational modification that is responsive to nutrient availably via the hexosamine biosynthetic pathway and its endproduct UDP-GlcNAc. O-GlcNAcylation serves as a nutrient sensor to regulate the activities of many proteins involved in nearly all biological processes. Within the last decade, OGT, OGA and O-GlcNAcylation have been shown to be at the nexus of epigenetic marks controlling gene expression during embryonic development, cell differentiation, in the maintenance of epigenetic states and in the etiology of epigenetic related diseases. OGT O-GlcNAcylates histones and epigenetic writers/erasers, and regulates gene activation, as well as gene repression. Here, we highlight recent work documenting the important roles O-GlcNAcylation and its cycling enzymes play in the nutrient regulation of epigenetic partners controlling gene expression.
Topics: Acetylglucosamine; Epigenesis, Genetic; Gene Expression Regulation; Histones; Humans
PubMed: 27322399
DOI: 10.1016/j.cbpa.2016.06.005 -
The Journal of Biological Chemistry Mar 2024The emerging roles of O-GlcNAcylation, a distinctive post-translational modification, are increasingly recognized for their involvement in the intricate processes of... (Review)
Review
The emerging roles of O-GlcNAcylation, a distinctive post-translational modification, are increasingly recognized for their involvement in the intricate processes of protein trafficking and secretion. This modification exerts its influence on both conventional and unconventional secretory pathways. Under healthy and stress conditions, such as during diseases, it orchestrates the transport of proteins within cells, ensuring timely delivery to their intended destinations. O-GlcNAcylation occurs on key factors, like coat protein complexes (COPI and COPII), clathrin, SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors), and GRASP55 (Golgi reassembly stacking protein of 55 kDa) that control vesicle budding and fusion in anterograde and retrograde trafficking and unconventional secretion. The understanding of O-GlcNAcylation offers valuable insights into its critical functions in cellular physiology and the progression of diseases, including neurodegeneration, cancer, and metabolic disorders. In this review, we summarize and discuss the latest findings elucidating the involvement of O-GlcNAc in protein trafficking and its significance in various human disorders.
Topics: Humans; Acetylglucosamine; Clathrin; Protein Processing, Post-Translational; Protein Transport; SNARE Proteins; Animals; Acetylation; Glucose
PubMed: 38272225
DOI: 10.1016/j.jbc.2024.105677 -
DNA Repair Nov 2022O-Linked β-N-acetylglucosamine glycosylation (O-GlcNAcylation) to serine or threonine residues is a reversible and dynamic post-translational modification. O-GlcNAc...
O-Linked β-N-acetylglucosamine glycosylation (O-GlcNAcylation) to serine or threonine residues is a reversible and dynamic post-translational modification. O-GlcNAc transferase (OGT) is the only enzyme for O-GlcNAcylation, and is a potential cancer therapeutic target in combination with clastogenic (i.e., chromosomal breaking) therapeutics. Thus, we sought to examine the influence of O-GlcNAcylation on chromosomal break repair. Using a set of DNA double strand break (DSB) reporter assays, we found that the depletion of OGT, and its inhibition with a small molecule each caused a reduction in repair pathways that involve use of homology: RAD51-dependent homology-directed repair (HDR), and single strand annealing. In contrast, such OGT disruption did not obviously affect chromosomal break end joining, and furthermore caused an increase in homology-directed gene targeting. Such disruption in OGT also caused a reduction in clonogenic survival, as well as modifications to cell cycle profiles, particularly an increase in G1-phase cells. We also examined intermediate steps of HDR, finding no obvious effects on an assay for DSB end resection, nor for RAD51 recruitment into ionizing radiation induced foci (IRIF) in proliferating cells. However, we also found that the influence of OGT on HDR and homology-directed gene targeting were dependent on RAD52, and that OGT is important for RAD52 IRIF in proliferating cells. Thus, we suggest that OGT is important for regulation of HDR that is partially linked to RAD52 function.
Topics: Acetylglucosamine; Chromosome Breakage; DNA; Humans; N-Acetylglucosaminyltransferases; Serine; Threonine
PubMed: 36095925
DOI: 10.1016/j.dnarep.2022.103394 -
Journal of Translational Medicine Oct 2017GlycA is a novel spectroscopic marker of systemic inflammation with low intra-individual variability and other attributes favoring its clinical use in patients with... (Review)
Review
BACKGROUND
GlycA is a novel spectroscopic marker of systemic inflammation with low intra-individual variability and other attributes favoring its clinical use in patients with chronic inflammatory and autoimmune diseases. GlycA is unique in its composite nature, reflecting both increased glycan complexity and circulating acute phase protein levels during local and systemic inflammation. Recent studies of GlycA from cross-sectional, observational and interventional studies have been highly informative, demonstrating that GlycA is elevated in acute and chronic inflammation, predicts death in healthy individuals and is associated with disease severity in patients with chronic inflammatory diseases such as rheumatoid arthritis, psoriasis and lupus. Moreover, following treatment with biological therapy in psoriasis, reduction in skin disease severity was accompanied by a decrease in GlycA levels and improvement in vascular inflammation.
CONCLUSIONS
Collectively, these findings suggest GlycA is a marker that tracks systemic inflammation and subclinical vascular inflammation. However, larger prospective studies and randomized trials are necessary in order to assess the impact of novel therapies on GlycA in patients with chronic inflammatory conditions, which may be concomitant with cardiovascular benefits.
Topics: Acetylglucosamine; Biomarkers; C-Reactive Protein; Cardiovascular Diseases; Humans; Inflammation; Risk Factors
PubMed: 29078787
DOI: 10.1186/s12967-017-1321-6 -
Biochemical Society Transactions Feb 2017In the 30 years, since the discovery of nucleocytoplasmic glycosylation, -GlcNAc has been implicated in regulating cellular processes as diverse as protein folding,... (Review)
Review
In the 30 years, since the discovery of nucleocytoplasmic glycosylation, -GlcNAc has been implicated in regulating cellular processes as diverse as protein folding, localization, degradation, activity, post-translational modifications, and interactions. The cell co-ordinates these molecular events, on thousands of cellular proteins, in concert with environmental and physiological cues to fine-tune epigenetics, transcription, translation, signal transduction, cell cycle, and metabolism. The cellular stress response is no exception: diverse forms of injury result in dynamic changes to the -GlcNAc subproteome that promote survival. In this review, we discuss the biosynthesis of -GlcNAc, the mechanisms by which -GlcNAc promotes cytoprotection, and the clinical significance of these data.
Topics: Acetylglucosamine; Adaptation, Physiological; Animals; Cell Survival; Glycosylation; Humans; Models, Biological; Protein Processing, Post-Translational; Signal Transduction; Stress, Physiological
PubMed: 28202678
DOI: 10.1042/BST20160153 -
The Journal of Biological Chemistry Dec 2014O-GlcNAc signaling is regulated by an opposing pair of enzymes: O-GlcNAc transferase installs and O-GlcNAcase (OGA) removes the modification from proteins. The dynamics... (Review)
Review
O-GlcNAc signaling is regulated by an opposing pair of enzymes: O-GlcNAc transferase installs and O-GlcNAcase (OGA) removes the modification from proteins. The dynamics and regulation of this process are only beginning to be understood as the physiological functions of both enzymes are being probed using genetic and pharmacological approaches. This minireview charts the discovery and functional and structural analysis of OGA and summarizes the insights gained from recent studies using OGA inhibition, gene knock-out, and overexpression. We identify several areas of "known unknowns" that would benefit from future research, such as the enigmatic C-terminal domain of OGA.
Topics: Acetylglucosamine; Animals; Enzyme Inhibitors; Humans; Signal Transduction; Substrate Specificity; beta-N-Acetylhexosaminidases
PubMed: 25336650
DOI: 10.1074/jbc.R114.609198 -
Journal of the American Chemical Society Mar 2022Posttranslational modifications alter the biophysical properties of proteins and thereby influence cellular physiology. One emerging manner by which such modifications...
Posttranslational modifications alter the biophysical properties of proteins and thereby influence cellular physiology. One emerging manner by which such modifications regulate protein functions is through their ability to perturb protein stability. Despite the increasing interest in this phenomenon, there are few methods that enable global interrogation of the biophysical effects of posttranslational modifications on the proteome. Here, we describe an unbiased proteome-wide approach to explore the influence of protein modifications on the thermodynamic stability of thousands of proteins in parallel. We apply this profiling strategy to study the effects of O-linked -acetylglucosamine (O-GlcNAc), an abundant modification found on hundreds of proteins in mammals that has been shown in select cases to stabilize proteins. Using this thermal proteomic profiling strategy, we identify a set of 72 proteins displaying O-GlcNAc-dependent thermostability and validate this approach using orthogonal methods targeting specific proteins. These collective observations reveal that the majority of proteins influenced by O-GlcNAc are, surprisingly, destabilized by O-GlcNAc and cluster into distinct macromolecular complexes. These results establish O-GlcNAc as a bidirectional regulator of protein stability and provide a blueprint for exploring the impact of any protein modification on the meltome of, in principle, any organism.
Topics: Acetylglucosamine; Animals; Mammals; Protein Processing, Post-Translational; Proteome; Proteomics
PubMed: 35230102
DOI: 10.1021/jacs.1c10621