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Traffic (Copenhagen, Denmark) Aug 2023Deficiency in the conserved oligomeric Golgi (COG) complex that orchestrates SNARE-mediated tethering/fusion of vesicles that recycle the Golgi's glycosylation machinery...
Deficiency in the conserved oligomeric Golgi (COG) complex that orchestrates SNARE-mediated tethering/fusion of vesicles that recycle the Golgi's glycosylation machinery results in severe glycosylation defects. Although two major Golgi v-SNAREs, GS28/GOSR1, and GS15/BET1L, are depleted in COG-deficient cells, the complete knockout of GS28 and GS15 only modestly affects Golgi glycosylation, indicating the existence of an adaptation mechanism in Golgi SNARE. Indeed, quantitative mass-spectrometry analysis of STX5-interacting proteins revealed two novel Golgi SNARE complexes-STX5/SNAP29/VAMP7 and STX5/VTI1B/STX8/YKT6. These complexes are present in wild-type cells, but their usage is significantly increased in both GS28- and COG-deficient cells. Upon GS28 deletion, SNAP29 increased its Golgi residency in a STX5-dependent manner. While STX5 depletion and Retro2-induced diversion from the Golgi severely affect protein glycosylation, GS28/SNAP29 and GS28/VTI1B double knockouts alter glycosylation similarly to GS28 KO, indicating that a single STX5-based SNARE complex is sufficient to support Golgi glycosylation. Importantly, co-depletion of three Golgi SNARE complexes in GS28/SNAP29/VTI1B TKO cells resulted in severe glycosylation defects and a reduced capacity for glycosylation enzyme retention at the Golgi. This study demonstrates the remarkable plasticity in SXT5-mediated membrane trafficking, uncovering a novel adaptive response to the failure of canonical intra-Golgi vesicle tethering/fusion machinery.
Topics: Qa-SNARE Proteins; Golgi Apparatus; SNARE Proteins
PubMed: 37340984
DOI: 10.1111/tra.12903 -
BMC Medicine Jul 2023A dysregulated postprandial metabolic response is a risk factor for chronic diseases, including type 2 diabetes mellitus (T2DM). The plasma protein N-glycome is... (Review)
Review
BACKGROUND
A dysregulated postprandial metabolic response is a risk factor for chronic diseases, including type 2 diabetes mellitus (T2DM). The plasma protein N-glycome is implicated in both lipid metabolism and T2DM risk. Hence, we first investigate the relationship between the N-glycome and postprandial metabolism and then explore the mediatory role of the plasma N-glycome in the relationship between postprandial lipaemia and T2DM.
METHODS
We included 995 individuals from the ZOE-PREDICT 1 study with plasma N-glycans measured by ultra-performance liquid chromatography at fasting and triglyceride, insulin, and glucose levels measured at fasting and following a mixed-meal challenge. Linear mixed models were used to investigate the associations between plasma protein N-glycosylation and metabolic response (fasting, postprandial (C), or change from fasting). A mediation analysis was used to further explore the relationship of the N-glycome in the prediabetes (HbA1c = 39-47 mmol/mol (5.7-6.5%))-postprandial lipaemia association.
RESULTS
We identified 36 out of 55 glycans significantly associated with postprandial triglycerides (C β ranging from -0.28 for low-branched glycans to 0.30 for GP26) after adjusting for covariates and multiple testing (p < 0.05). N-glycome composition explained 12.6% of the variance in postprandial triglycerides not already explained by traditional risk factors. Twenty-seven glycans were also associated with postprandial glucose and 12 with postprandial insulin. Additionally, 3 of the postprandial triglyceride-associated glycans (GP9, GP11, and GP32) also correlate with prediabetes and partially mediate the relationship between prediabetes and postprandial triglycerides.
CONCLUSIONS
This study provides a comprehensive overview of the interconnections between plasma protein N-glycosylation and postprandial responses, demonstrating the incremental predictive benefit of N-glycans. We also suggest a considerable proportion of the effect of prediabetes on postprandial triglycerides is mediated by some plasma N-glycans.
Topics: Humans; Diabetes Mellitus, Type 2; Blood Glucose; Prediabetic State; Triglycerides; Insulin; Hyperlipidemias; Polysaccharides; Blood Proteins
PubMed: 37400796
DOI: 10.1186/s12916-023-02938-z -
Orphanet Journal of Rare Diseases Oct 2023Congenital disorders of glycosylation (CDG) are a complex and heterogeneous family of rare metabolic diseases. With a clinical history that dates back over 40 years, it... (Review)
Review
Congenital disorders of glycosylation (CDG) are a complex and heterogeneous family of rare metabolic diseases. With a clinical history that dates back over 40 years, it was the recent multi-omics advances that mainly contributed to the fast-paced and encouraging developments in the field. However, much remains to be understood, with targeted therapies' discovery and approval being the most urgent unmet need. In this paper, we present the 2022 state of the art of CDG, including glycosylation pathways, phenotypes, genotypes, inheritance patterns, biomarkers, disease models, and treatments. In light of our current knowledge, it is not always clear whether a specific disease should be classified as a CDG. This can create ambiguity among professionals leading to confusion and misguidance, consequently affecting the patients and their families. This review aims to provide the CDG community with a comprehensive overview of the recent progress made in this field.
Topics: Humans; Congenital Disorders of Glycosylation; Glycosylation; Biomarkers; Phenotype; Genotype
PubMed: 37858231
DOI: 10.1186/s13023-023-02879-z -
Cell Death & Disease Aug 2023KIAA1324 is a transmembrane protein largely reported as a tumor suppressor and favorable prognosis marker in various cancers, including gastric cancer. In this study, we...
KIAA1324 is a transmembrane protein largely reported as a tumor suppressor and favorable prognosis marker in various cancers, including gastric cancer. In this study, we report the role of N-linked glycosylation in KIAA1324 as a functional post-translational modification (PTM). Loss of N-linked glycosylation eliminated the potential of KIAA1324 to suppress cancer cell proliferation and migration. Furthermore, we demonstrated that KIAA1324 undergoes fucosylation, a modification of the N-glycan mediated by fucosyltransferase, and inhibition of fucosylation also significantly suppressed KIAA1324-induced cell growth inhibition and apoptosis of gastric cancer cells. In addition, KIAA1324-mediated apoptosis and tumor regression were inhibited by the loss of N-linked glycosylation. RNA sequencing (RNAseq) analysis revealed that genes most relevant to the apoptosis and cell cycle arrest pathways were modulated by KIAA1324 with the N-linked glycosylation, and Gene Regulatory Network (GRN) analysis suggested novel targets of KIAA1324 for anti-tumor effects in the transcription level. The N-linked glycosylation blockade decreased protein stability through rapid proteasomal degradation. The non-glycosylated mutant also showed altered localization and lost apoptotic activity that inhibits the interaction between GRP78 and caspase 7. These data demonstrate that N-linked glycosylation of KIAA1324 is essential for the suppressive role of KIAA1324 protein in gastric cancer progression and indicates that KIAA1324 may have anti-tumor effects by targeting cancer-related genes with N-linked glycosylation. In conclusion, our study suggests the PTM of KIAA1324 including N-linked glycosylation and fucosylation is a necessary factor to consider for cancer prognosis and therapy improvement.
Topics: Humans; Stomach Neoplasms; Glycosylation; Protein Processing, Post-Translational; Fucosyltransferases
PubMed: 37612293
DOI: 10.1038/s41419-023-06083-6 -
Autoimmunity Reviews Sep 2023Psoriatic arthritis (PsA) is an inflammatory complex condition. Posttranslational modifications influence almost all aspects of normal cell biology and pathogenesis. The... (Review)
Review
BACKGROUND AND AIMS
Psoriatic arthritis (PsA) is an inflammatory complex condition. Posttranslational modifications influence almost all aspects of normal cell biology and pathogenesis. The aim of this systematic review was to collect all published evidence regarding posttranslational modifications in PsA, and the main outcome was to evaluate an association between disease outcomes and specific posttranslational modifications in PsA.
METHODS
A systematic electronic search was performed in Medline, PubMed, Cochrane, Virtual Health Library, and Embase databases. A total of 587 articles were identified; 59 were evaluated after removing duplicates and scanning, of which 47 were included. A descriptive analysis was conducted, with results grouped according to the type of posttranslational modification evaluated. The protocol was registered at the PROSPERO database.
RESULTS
Seven posttranslational modifications were identified: citrullination, carbamylation, phosphorylation, glycosylation, acetylation, methylation, and oxidative stress. Anti-citrullinated peptide and anti-carbamylated protein have been evaluated in rheumatoid arthritis. There is now information suggesting that these antibodies may be helpful in improving the diagnosis of PsA and that they may demonstrate a correlation with worse disease progression (erosions, polyarticular involvement, and poor treatment response). Glycosylation was associated with increased inflammation and phosphorylation products related to the expression of SIRT2 and pSTAT3 or the presence of Th17 and cytokine interleukin-22, suggesting a possible therapeutic target.
CONCLUSIONS
Posttranslational modifications often play a key role in modulating protein function in PsA and correlate with disease outcomes. Citrullination, carbamylation, phosphorylation, glycosylation, acetylation, methylation, and oxidative stress were identified as associated with diagnosis and prognosis.
Topics: Humans; Arthritis, Psoriatic; Protein Processing, Post-Translational; Citrullination; Glycosylation; Arthritis, Rheumatoid
PubMed: 37487969
DOI: 10.1016/j.autrev.2023.103393 -
Nature Communications Jul 2023The unique dumbbell-shape of grass guard cells (GCs) is controlled by their cell walls which enable their rapid responses to the environment. The molecular mechanisms...
The unique dumbbell-shape of grass guard cells (GCs) is controlled by their cell walls which enable their rapid responses to the environment. The molecular mechanisms regulating the synthesis and assembly of GC walls are as yet unknown. Here we have identified BZU3, a maize gene encoding UDP-glucose 4-epimerase that regulates the supply of UDP-glucose during GC wall synthesis. The BZU3 mutation leads to significant decreases in cellular UDP-glucose levels. Immunofluorescence intensities reporting levels of cellulose and mixed-linkage glucans are reduced in the GCs, resulting in impaired local wall thickening. BZU3 also catalyzes the epimerization of UDP-N-acetylgalactosamine to UDP-N-acetylglucosamine, and the BZU3 mutation affects N-glycosylation of proteins that may be involved in cell wall synthesis and signaling. Our results suggest that the spatiotemporal modulation of BZU3 plays a dual role in controlling cell wall synthesis and glycosylation via controlling UDP-glucose/N-acetylglucosamine homeostasis during stomatal morphogenesis. These findings provide insights into the mechanisms controlling formation of the unique morphology of grass stomata.
Topics: Zea mays; Racemases and Epimerases; Glycosylation; Acetylglucosamine; Poaceae; Cell Wall; Uridine Diphosphate
PubMed: 37474494
DOI: 10.1038/s41467-023-40013-6 -
Journal of Bacteriology Jun 2023Flavobacterium johnsoniae is a free-living member of the phylum that is found in soil and water. It is frequently used as a model species for studying a type of gliding...
Flavobacterium johnsoniae is a free-living member of the phylum that is found in soil and water. It is frequently used as a model species for studying a type of gliding motility dependent on the type IX secretion system (T9SS). -Glycosylation has been reported in several species, and the -glycosylation of S-layer proteins in Tannerella forsythia was shown to be important for certain virulence features. In this study, we characterized the -glycoproteome of F. johnsoniae and identified 325 -glycosylation sites within 226 glycoproteins. The structure of the major glycan was found to be a hexasaccharide with the sequence Hex-(Me-dHex)-Me-HexA-Pent-HexA-Me-HexNAcA. Bioinformatic localization of the glycoproteins predicted 68 inner membrane proteins, 60 periplasmic proteins, 26 outer membrane proteins, 57 lipoproteins, and 9 proteins secreted by the T9SS. The glycosylated sites were predominantly located in the periplasm, where they are postulated to be beneficial for protein folding/stability. Six proteins associated with gliding motility or the T9SS were demonstrated to be -glycosylated. Flavobacterium johnsoniae is a Gram-negative bacterium that is found in soil and water. It is frequently used as a model species for studying gliding motility and the T9SS. In this study, we characterized the -glycoproteome of F. johnsoniae and identified 325 -glycosylation sites within 226 glycoproteins. The glycosylated domains were mainly localized to the periplasm. The function of -glycosylation is likely related to protein folding and stability; therefore, the finding of the glycosylation sites has relevance for studies involving expression of the proteins. Six proteins associated with gliding motility or the T9SS were demonstrated to be -glycosylated, which may impact the structure and function of these components.
Topics: Bacterial Proteins; Flavobacterium; Polysaccharides; Glycosylation; Proteome
PubMed: 37162352
DOI: 10.1128/jb.00093-23 -
Journal of Proteome Research Oct 2023Inflammatory bowel diseases (IBD), such as Crohn's disease (CD) and ulcerative colitis (UC), are chronic and relapsing inflammations of the digestive tract with...
Inflammatory bowel diseases (IBD), such as Crohn's disease (CD) and ulcerative colitis (UC), are chronic and relapsing inflammations of the digestive tract with increasing prevalence, yet they have unknown origins or cure. CD and UC have similar symptoms but respond differently to surgery and medication. Current diagnostic tools often involve invasive procedures, while laboratory markers for patient stratification are lacking. Large glycomic studies of immunoglobulin G and total plasma glycosylation have shown biomarker potential in IBD and could help determine disease mechanisms and therapeutic treatment choice. Hitherto, the glycosylation signatures of plasma immunoglobulin A, an important immunoglobulin secreted into the intestinal mucin, have remained undetermined in the context of IBD. Our study investigated the associations of immunoglobulin A1 and A2 glycosylation with IBD in 442 IBD cases (188 CD and 254 UC) and 120 healthy controls by reversed-phase liquid chromatography electrospray-ionization mass spectrometry of tryptic glycopeptides. Differences of IgA and -glycosylation (including galactosylation, bisection, sialylation, and antennarity) between patient groups were associated with the diseases, and these findings led to the construction of a statistical model to predict the disease group of the patients without the need of invasive procedures. This study expands the current knowledge about CD and UC and could help in the development of noninvasive biomarkers and better patient care.
Topics: Humans; Crohn Disease; Colitis, Ulcerative; Glycosylation; Immunoglobulin A; Inflammatory Bowel Diseases; Biomarkers
PubMed: 37641533
DOI: 10.1021/acs.jproteome.3c00260 -
Biotechnology Advances 2024A key aspect of successful viral vaccine design is the elicitation of neutralizing antibodies targeting viral attachment and fusion glycoproteins that embellish viral... (Review)
Review
A key aspect of successful viral vaccine design is the elicitation of neutralizing antibodies targeting viral attachment and fusion glycoproteins that embellish viral particles. This observation has catalyzed the development of numerous viral glycoprotein mimetics as vaccines. Glycans can dominate the surface of viral glycoproteins and as such, the viral glycome can influence the antigenicity and immunogenicity of a candidate vaccine. In one extreme, glycans can form an integral part of epitopes targeted by neutralizing antibodies and are therefore considered to be an important feature of key immunogens within an immunization regimen. In the other extreme, the existence of peptide and bacterially expressed protein vaccines shows that viral glycosylation can be dispensable in some cases. However, native-like glycosylation can indicate native-like protein folding and the presence of conformational epitopes. Furthermore, going beyond native glycan mimicry, in either occupancy of glycosylation sites or the glycan processing state, may offer opportunities for enhancing the immunogenicity and associated protection elicited by an immunogen. Here, we review key determinants of viral glycosylation and how recombinant immunogens can recapitulate these signatures across a range of enveloped viruses, including HIV-1, Ebola virus, SARS-CoV-2, Influenza and Lassa virus. The emerging understanding of immunogen glycosylation and its control will help guide the development of future vaccines in both recombinant protein- and nucleic acid-based vaccine technologies.
Topics: Glycosylation; Glycoproteins; Antibodies, Neutralizing; Epitopes; Vaccines; Polysaccharides
PubMed: 37972669
DOI: 10.1016/j.biotechadv.2023.108283 -
ELife Jul 2023The DNA methyltransferase activity of DNMT1 is vital for genomic maintenance of DNA methylation. We report here that DNMT1 function is regulated by -GlcNAcylation, a...
The DNA methyltransferase activity of DNMT1 is vital for genomic maintenance of DNA methylation. We report here that DNMT1 function is regulated by -GlcNAcylation, a protein modification that is sensitive to glucose levels, and that elevated -GlcNAcylation of DNMT1 from high glucose environment leads to alterations to the epigenome. Using mass spectrometry and complementary alanine mutation experiments, we identified S878 as the major residue that is -GlcNAcylated on human DNMT1. Functional studies in human and mouse cells further revealed that -GlcNAcylation of DNMT1-S878 results in an inhibition of methyltransferase activity, resulting in a general loss of DNA methylation that preferentially occurs at partially methylated domains (PMDs). This loss of methylation corresponds with an increase in DNA damage and apoptosis. These results establish -GlcNAcylation of DNMT1 as a mechanism through which the epigenome is regulated by glucose metabolism and implicates a role for glycosylation of DNMT1 in metabolic diseases characterized by hyperglycemia.
Topics: Mice; Humans; Animals; Glucose; Epigenome; DNA (Cytosine-5-)-Methyltransferase 1; DNA Methylation; Glycosylation; Hyperglycemia
PubMed: 37470704
DOI: 10.7554/eLife.85595