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Nature Nov 2023Identifying metabolic steps that are specifically required for the survival of cancer cells but are dispensable in normal cells remains a challenge. Here we report a...
Identifying metabolic steps that are specifically required for the survival of cancer cells but are dispensable in normal cells remains a challenge. Here we report a therapeutic vulnerability in a sugar nucleotide biosynthetic pathway that can be exploited in cancer cells with only a limited impact on normal cells. A systematic examination of conditionally essential metabolic enzymes revealed that UXS1, a Golgi enzyme that converts one sugar nucleotide (UDP-glucuronic acid, UDPGA) to another (UDP-xylose), is essential only in cells that express high levels of the enzyme immediately upstream of it, UGDH. This conditional relationship exists because UXS1 is required to prevent excess accumulation of UDPGA, which is produced by UGDH. UXS1 not only clears away UDPGA but also limits its production through negative feedback on UGDH. Excess UDPGA disrupts Golgi morphology and function, which impedes the trafficking of surface receptors such as EGFR to the plasma membrane and diminishes the signalling capacity of cells. UGDH expression is elevated in several cancers, including lung adenocarcinoma, and is further enhanced during chemoresistant selection. As a result, these cancer cells are selectively dependent on UXS1 for UDPGA detoxification, revealing a potential weakness in tumours with high levels of UGDH.
Topics: Humans; Neoplasms; Signal Transduction; Uridine Diphosphate Glucuronic Acid; Uridine Diphosphate Xylose; Adenocarcinoma of Lung; Lung Neoplasms
PubMed: 37880368
DOI: 10.1038/s41586-023-06676-3 -
Molecules (Basel, Switzerland) Aug 2022Rhamnose-associated molecules are attracting attention because they are present in bacteria but not mammals, making them potentially useful as antibacterial agents.... (Review)
Review
Rhamnose-associated molecules are attracting attention because they are present in bacteria but not mammals, making them potentially useful as antibacterial agents. Additionally, they are also valuable for tumor immunotherapy. Thus, studies on the functions and biosynthetic pathways of rhamnose-containing compounds are in progress. In this paper, studies on the biosynthetic pathways of three rhamnose donors, i.e., deoxythymidinediphosphate-L-rhamnose (dTDP-Rha), uridine diphosphate-rhamnose (UDP-Rha), and guanosine diphosphate rhamnose (GDP-Rha), are firstly reviewed, together with the functions and crystal structures of those associated enzymes. Among them, dTDP-Rha is the most common rhamnose donor, and four enzymes, including glucose-1-phosphate thymidylyltransferase RmlA, dTDP-Glc-4,6-dehydratase RmlB, dTDP-4-keto-6-deoxy-Glc-3,5-epimerase RmlC, and dTDP-4-keto-Rha reductase RmlD, are involved in its biosynthesis. Secondly, several known rhamnosyltransferases from , , , , and are discussed. In these studies, however, the functions of rhamnosyltransferases were verified by employing gene knockout and radiolabeled substrates, which were almost impossible to obtain and characterize the products of enzymatic reactions. Finally, the application of rhamnose-containing compounds in disease treatments is briefly described.
Topics: Biosynthetic Pathways; Racemases and Epimerases; Rhamnose; Thymine Nucleotides; Uridine Diphosphate
PubMed: 36014553
DOI: 10.3390/molecules27165315 -
Chembiochem : a European Journal of... Jan 2022High costs and low availability of UDP-galactose hampers the enzymatic synthesis of valuable oligosaccharides such as human milk oligosaccharides. Here, we report the...
High costs and low availability of UDP-galactose hampers the enzymatic synthesis of valuable oligosaccharides such as human milk oligosaccharides. Here, we report the development of a platform for the scalable, biocatalytic synthesis and purification of UDP-galactose. UDP-galactose was produced with a titer of 48 mM (27.2 g/L) in a small-scale batch process (200 μL) within 24 h using 0.02 g /g . Through in-situ ATP regeneration, the amount of ATP (0.6 mM) supplemented was around 240-fold lower than the stoichiometric equivalent required to achieve the final product yield. Chromatographic purification using porous graphic carbon adsorbent yielded UDP-galactose with a purity of 92 %. The synthesis was transferred to 1 L preparative scale production in a stirred tank bioreactor. To further reduce the synthesis costs here, the supernatant of cell lysates was used bypassing expensive purification of enzymes. Here, 23.4 g/L UDP-galactose were produced within 23 h with a synthesis yield of 71 % and a biocatalyst load of 0.05 g /g . The costs for substrates per gram of UDP-galactose synthesized were around 0.26 €/g.
Topics: Adenosine Triphosphate; Bioreactors; Cell-Free System; Enzymes; Hydrogen-Ion Concentration; Oligosaccharides; Proof of Concept Study; Uridine Diphosphate Galactose
PubMed: 34637168
DOI: 10.1002/cbic.202100361 -
Scientific Reports Aug 2022Insulin secretion is regulated in multiple steps, and one of the main steps is in the endoplasmic reticulum (ER). Here, we show that UDP-glucose induces proinsulin...
Insulin secretion is regulated in multiple steps, and one of the main steps is in the endoplasmic reticulum (ER). Here, we show that UDP-glucose induces proinsulin ubiquitination by cereblon, and uridine binds and competes for proinsulin degradation and behaves as sustainable insulin secretagogue. Using insulin mutagenesis of neonatal diabetes variant-C43G and maturity-onset diabetes of the young 10 (MODY10) variant-R46Q, UDP-glucose:glycoprotein glucosyltransferase 1 (UGGT1) protects cereblon-dependent proinsulin ubiquitination in the ER. Cereblon is a ligand-inducible E3 ubiquitin ligase, and we found that UDP-glucose is the first identified endogenous proinsulin protein degrader. Uridine-containing compounds, such as uridine, UMP, UTP, and UDP-galactose, inhibit cereblon-dependent proinsulin degradation and stimulate insulin secretion from 3 to 24 h after administration in β-cell lines as well as mice. This late and long-term insulin secretion stimulation is designated a day sustainable insulin secretion stimulation. Uridine-containing compounds are designated as proinsulin degradation regulators.
Topics: Animals; Diabetes Mellitus, Type 2; Glucose; Insulin; Insulin-Secreting Cells; Mice; Proinsulin; Uridine; Uridine Diphosphate Glucose
PubMed: 36028536
DOI: 10.1038/s41598-022-18902-5 -
Cold Spring Harbor Perspectives in... Dec 2019Glycosylation plays a major role in the structural diversification of plant natural products. It influences the properties of molecules by modifying the reactivity and... (Review)
Review
Glycosylation plays a major role in the structural diversification of plant natural products. It influences the properties of molecules by modifying the reactivity and solubility of the corresponding aglycones, so influencing cellular localization and bioactivity. Glycosylation of plant natural products is usually carried out by uridine diphosphate(UDP)-dependent glycosyltransferases (UGTs) belonging to the carbohydrate-active enzyme glycosyltransferase 1 (GT1) family. These enzymes transfer sugars from UDP-activated sugar moieties to small hydrophobic acceptor molecules. Plant GT1s generally show high specificity for their sugar donors and recognize a single UDP sugar as their substrate. In contrast, they are generally promiscuous with regard to acceptors, making them attractive biotechnological tools for small molecule glycodiversification. Although microbial hosts have traditionally been used for heterologous engineering of plant-derived glycosides, transient plant expression technology offers a potentially disruptive platform for rapid characterization of new plant glycosyltransferases and biosynthesis of complex glycosides.
Topics: Biocatalysis; Biological Products; Glycosylation; Glycosyltransferases; Phylogeny; Plants; Protein Conformation; Uridine Diphosphate
PubMed: 31235546
DOI: 10.1101/cshperspect.a034744 -
Molecular Plant Apr 2023During effector-triggered immunity (ETI) against the devastating rice blast pathogen Magnaporthe oryzae, Pi9 functions as an intracellular resistance protein sensing the...
During effector-triggered immunity (ETI) against the devastating rice blast pathogen Magnaporthe oryzae, Pi9 functions as an intracellular resistance protein sensing the pathogen-secreted effector AvrPi9 in rice. Importantly, the underlying recognition mechanism(s) between Pi9 and AvrPi9 remains elusive. In this study, we identified a rice ubiquitin-like domain-containing protein (UDP), AVRPI9-INTERACTING PROTEIN 1 (ANIP1), which is directly targeted by AvrPi9 and also binds to Pi9 in plants. Phenotypic analysis of anip1 mutants and plants overexpressing ANIP1 revealed that ANIP1 negatively modulates rice basal defense against M. oryzae. ANIP1 undergoes 26S proteasome-mediated degradation, which can be blocked by both AvrPi9 and Pi9. Moreover, ANIP1 physically associates with the rice WRKY transcription factor OsWRKY62, which also interacts with AvrPi9 and Pi9 in plants. In the absence of Pi9, ANIP1 negatively regulates OsWRKY62 abundance, which can be promoted by AvrPi9. Accordingly, knocking out of OsWRKY62 in a non-Pi9 background decreased immunity against M. oryzae. However, we also observed that OsWRKY62 plays negative roles in defense against a compatible M. oryzae strain in Pi9-harboring rice. Pi9 binds to ANIP1 and OsWRKY62 to form a complex, which may help to keep Pi9 in an inactive state and weaken rice immunity. Furthermore, using competitive binding assays, we showed that AvrPi9 promotes Pi9 dissociation from ANIP1, which could be an important step toward ETI activation. Taken together, our results reveal an immune strategy whereby a UDP-WRKY module, targeted by a fungal effector, modulates rice immunity in distinct ways in the presence or absence of the corresponding resistance protein.
Topics: Magnaporthe; Ascomycota; Transcription Factors; Uridine Diphosphate; Oryza; Plant Diseases; Disease Resistance
PubMed: 36872602
DOI: 10.1016/j.molp.2023.03.001 -
The Journal of Histochemistry and... Jan 2021Hyaluronan (HA) is a linear glycosaminoglycan (GAG) of extracellular matrix (ECM) synthesized by three hyaluronan synthases (HASes) at the plasma membrane using uridine... (Review)
Review
Hyaluronan (HA) is a linear glycosaminoglycan (GAG) of extracellular matrix (ECM) synthesized by three hyaluronan synthases (HASes) at the plasma membrane using uridine diphosphate (UDP)-glucuronic acid (UDP-GlcUA) and UDP-acetylglucosamine (UDP-GlcNAc) as substrates. The production of HA is mainly regulated by hyaluronan synthase 2 (HAS2), that can be controlled at different levels, from epigenetics to transcriptional and post-translational modifications. HA biosynthesis is an energy-consuming process and, along with HA catabolism, is strongly connected to the maintenance of metabolic homeostasis. The cytoplasmic pool of UDP-sugars is critical for HA synthesis. UDP-GlcNAc is an important nutrient sensor and serves as donor substrate for the -GlcNAcylation of many cytosolic proteins, including HAS2. This post-translational modification stabilizes HAS2 in the membrane and increases HA production. Conversely, HAS2 can be phosphorylated by AMP activated protein kinase (AMPK), a master metabolic regulator activated by low ATP/AMP ratios, which inhibits HA secretion. Similarly, HAS2 expression and the deposition of HA within the pericellular coat are inhibited by sirtuin 1 (SIRT1), another important energetic sensor, confirming the tight connection between nutrients availability and HA metabolism.
Topics: Animals; Biosynthetic Pathways; Energy Metabolism; Humans; Hyaluronan Synthases; Hyaluronic Acid; Uridine Diphosphate Glucuronic Acid; Uridine Diphosphate N-Acetylglucosamine
PubMed: 32623953
DOI: 10.1369/0022155420929772 -
Glycobiology Nov 2019l-arabinofuranose is a ubiquitous component of the cell wall and various natural products in plants, where it is synthesized from cytosolic UDP-arabinopyranose... (Review)
Review
l-arabinofuranose is a ubiquitous component of the cell wall and various natural products in plants, where it is synthesized from cytosolic UDP-arabinopyranose (UDP-Arap). The biosynthetic machinery long remained enigmatic in terms of responsible enzymes and subcellular localization. With the discovery of UDP-Arap mutase in plant cytosol, the demonstration of its role in cell-wall arabinose incorporation and the identification of UDP-arabinofuranose transporters in the Golgi membrane, it is clear that the cytosolic UDP-Arap mutases are the key enzymes converting UDP-Arap to UDP-arabinofuranose for cell wall and natural product biosynthesis. This has recently been confirmed by several genotype/phenotype studies. In contrast to the solid evidence pertaining to UDP-Arap mutase function in vivo, the molecular features, including enzymatic mechanism and oligomeric state, remain unknown. However, these enzymes belong to the small family of proteins originally identified as reversibly glycosylated polypeptides (RGPs), which has been studied for >20 years. Here, we review the UDP-Arap mutase and RGP literature together, to summarize and systemize reported molecular characteristics and relations to other proteins.
Topics: Biological Products; Cell Wall; Intramolecular Transferases; Oryza; Uridine Diphosphate Sugars
PubMed: 31679023
DOI: 10.1093/glycob/cwz067 -
Frontiers in Endocrinology 2022Purinergic receptors are ubiquitously expressed throughout the body and they participate in the autocrine and paracrine regulation of cell function during normal... (Review)
Review
Purinergic receptors are ubiquitously expressed throughout the body and they participate in the autocrine and paracrine regulation of cell function during normal physiological and pathophysiological conditions. Extracellular nucleotides activate several types of plasma membrane purinergic receptors that form three distinct families: P1 receptors are activated by adenosine, P2X receptors are activated by ATP, and P2Y receptors are activated by nucleotides including ATP, ADP, UTP, UDP, and UDP-glucose. These specific pharmacological fingerprints and the distinct intracellular signaling pathways they trigger govern a large variety of cellular responses in an organ-specific manner. As such, purinergic signaling regulates several physiological cell functions, including cell proliferation, differentiation and death, smooth muscle contraction, vasodilatation, and transepithelial transport of water, solute, and protons, as well as pathological pathways such as inflammation. While purinergic signaling was first discovered more than 90 years ago, we are just starting to understand how deleterious signals mediated through purinergic receptors may be involved in male infertility. A large fraction of male infertility remains unexplained illustrating our poor understanding of male reproductive health. Purinergic signaling plays a variety of physiological and pathophysiological roles in the male reproductive system, but our knowledge in this context remains limited. This review focuses on the distribution of purinergic receptors in the testis, epididymis, and vas deferens, and their role in the establishment and maintenance of male fertility.
Topics: Humans; Male; Testis; Infertility, Male; Nucleotides; Adenosine Triphosphate; Uridine Diphosphate
PubMed: 36419764
DOI: 10.3389/fendo.2022.1049511 -
Nature Oct 2022Chitin, the most abundant aminopolysaccharide in nature, is an extracellular polymer consisting of N-acetylglucosamine (GlcNAc) units. The key reactions of chitin...
Chitin, the most abundant aminopolysaccharide in nature, is an extracellular polymer consisting of N-acetylglucosamine (GlcNAc) units. The key reactions of chitin biosynthesis are catalysed by chitin synthase, a membrane-integrated glycosyltransferase that transfers GlcNAc from UDP-GlcNAc to a growing chitin chain. However, the precise mechanism of this process has yet to be elucidated. Here we report five cryo-electron microscopy structures of a chitin synthase from the devastating soybean root rot pathogenic oomycete Phytophthora sojae (PsChs1). They represent the apo, GlcNAc-bound, nascent chitin oligomer-bound, UDP-bound (post-synthesis) and chitin synthase inhibitor nikkomycin Z-bound states of the enzyme, providing detailed views into the multiple steps of chitin biosynthesis and its competitive inhibition. The structures reveal the chitin synthesis reaction chamber that has the substrate-binding site, the catalytic centre and the entrance to the polymer-translocating channel that allows the product polymer to be discharged. This arrangement reflects consecutive key events in chitin biosynthesis from UDP-GlcNAc binding and polymer elongation to the release of the product. We identified a swinging loop within the chitin-translocating channel, which acts as a 'gate lock' that prevents the substrate from leaving while directing the product polymer into the translocating channel for discharge to the extracellular side of the cell membrane. This work reveals the directional multistep mechanism of chitin biosynthesis and provides a structural basis for inhibition of chitin synthesis.
Topics: Acetylglucosamine; Aminoglycosides; Binding Sites; Cell Membrane; Chitin; Chitin Synthase; Cryoelectron Microscopy; Phytophthora; Uridine Diphosphate; Uridine Diphosphate N-Acetylglucosamine
PubMed: 36131020
DOI: 10.1038/s41586-022-05244-5