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Current Biology : CB Aug 2022Starch metabolism is linked to plant growth, yet blocking its biosynthesis has species-specific consequences. In a new study, plastidial phosphoglucomutase is knocked...
Starch metabolism is linked to plant growth, yet blocking its biosynthesis has species-specific consequences. In a new study, plastidial phosphoglucomutase is knocked out in aspen trees using CRISPR-Cas9, limiting starch production and altering photosynthesis, but growth, bud break and wood production proceed unaffected.
Topics: Carbohydrate Metabolism; Photosynthesis; Plant Leaves; Plastids; Starch; Trees
PubMed: 35998602
DOI: 10.1016/j.cub.2022.07.024 -
Journal of Applied Glycoscience 2022Lacto--biose I (LNB) is supposed to represent the bifidus factor in human milk oligosaccharides, and can be practically produced from sucrose and GlcNAc using four...
Lacto--biose I (LNB) is supposed to represent the bifidus factor in human milk oligosaccharides, and can be practically produced from sucrose and GlcNAc using four bifidobacterial enzymes, 1,3-β-galactosyl--acetylhexosamine phosphorylase, sucrose phosphorylase, UDP-glucose-hexose 1-phosphate uridylyltransferase, and UDP-glucose 4-epimerase, recombinantly produced by . Here the production of LNB by the same enzymatic method without using genetically modified enzymes to consider the use of LNB for a food ingredient was reported. All four enzymes were produced as the intracellular enzymes of strains. The mixture of the crude extracts contained all four enzymes, with other enzymes interfering with the LNB production, namely, phosphoglucomutase, fructose 6-phosphate phosphoketolase, and glycogen phosphorylase. The first two interfering enzymes were selectively inactivated by heat treatment at 47 °C for 1 h in the presence of pancreatin, and glycogen phosphorylase was disabled by hydrolyzing its possible acceptor molecules using glucoamylase. Finally, 91 % of GlcNAc was converted into LNB in the 100-mL reaction mixture containing 300 mM GlcNAc.
PubMed: 35891897
DOI: 10.5458/jag.jag.JAG-2021_0012 -
Cells Jul 2022Respiratory syncytial virus (RSV), or human orthopneumovirus, is a negative-sense RNA virus that is the causative agent of severe lower respiratory tract infections in...
Respiratory syncytial virus (RSV), or human orthopneumovirus, is a negative-sense RNA virus that is the causative agent of severe lower respiratory tract infections in children and is associated with exacerbations of adult lung disease. The mechanisms how severe and/or repetitive virus infections cause declines in pulmonary capacity are not fully understood. We have recently discovered that viral replication triggers epithelial plasticity and metabolic reprogramming involving the hexosamine biosynthetic pathway (HBP). In this study, we examine the relationship between viral induced innate inflammation and the activation of hexosamine biosynthesis in small airway epithelial cells. We observe that RSV induces ~2-fold accumulation of intracellular UDP-GlcNAc, the end-product of the HBP and the obligate substrate of N glycosylation. Using two different silencing approaches, we observe that RSV replication activates the HBP pathway in a manner dependent on the RELA proto-oncogene (65 kDa subunit). To better understand the effect of RSV on the cellular N glycoproteome, and its RELA dependence, we conduct affinity enriched LC-MS profiling in wild-type and RELA-silenced cells. We find that RSV induces the accumulation of 171 N glycosylated peptides in a RELA-dependent manner; these proteins are functionally enriched in integrins and basal lamina formation. To elaborate this mechanism of HBP expression, we demonstrate that RSV infection coordinately induces the HBP pathway enzymes in a manner requiring RELA; these genes include Glutamine-Fructose-6-Phosphate Transaminase 1 (GFPT)-1/2, Glucosamine-Phosphate N-Acetyltransferase (GNPNAT)-1, phosphoglucomutase (PGM)-3 and UDP-N-Acetylglucosamine Pyrophosphorylase (UAP)-1. Using small-molecule inhibitor(s) of 8-oxoguanine DNA glycosylase1 (OGG1), we observe that OGG1 is also required for the expression of HBP pathway. In proximity ligation assays, RSV induces the formation of a nuclear and mitochondrial RELA∙OGG1 complex. In co-immunoprecipitaton (IP) experiments, we discover that RSV induces Ser 536-phosphorylated RELA to complex with OGG1. Chromatin IP experiments demonstrate a major role of OGG1 in supporting the recruitment of RELA and phosphorylated RNA Pol II to the HBP pathway genes. We conclude that the RELA∙OGG1 complex is an epigenetic regulator mediating metabolic reprogramming and N glycoprotein modifications of integrins in response to RSV. These findings have implications for viral-induced adaptive epithelial responses.
Topics: Biosynthetic Pathways; DNA; DNA Glycosylases; Epigenesis, Genetic; Hexosamines; Humans; Integrins; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Human
PubMed: 35883652
DOI: 10.3390/cells11142210 -
Marine Drugs Jul 2022Agar is widely applied across the food, pharmaceutical and biotechnology industries, owing to its various bioactive functions. To better understand the agar biosynthesis...
Agar is widely applied across the food, pharmaceutical and biotechnology industries, owing to its various bioactive functions. To better understand the agar biosynthesis in commercial seaweed , the activities of four enzymes participating in the agar biosynthesis were detected, and phosphoglucomutase (PGM) was confirmed as highly correlated with agar accumulation. Three genes of (, and ) were identified from the genome. The subcellular localization analysis validated that GlPGM1 was located in the chloroplast and GlPGM3 was not significantly distributed in the organelles. Both the GlPGM1 and GlPGM3 protein levels showed a remarkable consistency with the agar variations, and GlPGM3 may participate in the carbon flux between (iso)floridoside, floridean starch and agar synthesis. After treatment with the PGM inhibitor, the agar and floridean starch contents and the activities of floridean starch synthase were significantly decreased; products identified in the Calvin cycle, the pentose phosphate pathway, the Embden-Meyerhof-Parnas pathway and the tricarboxylic acid cycle were depressed; however, lipids, phenolic acids and the intermediate metabolites, fructose-1,6-phosphate were upregulated. These findings reveal the essential role of PGM in regulating the carbon flux between agar and other carbohydrates in , providing a guide for the artificial regulation of agar accumulation.
Topics: Agar; Carbon Cycle; Phosphoglucomutase; Rhodophyta; Starch
PubMed: 35877735
DOI: 10.3390/md20070442 -
Marine Drugs Jun 2022The synthesis of cell-wall sulfated galactans proceeds through UDP galactose, a major nucleotide sugar in red seaweed, whilst sulfate is transported through...
The synthesis of cell-wall sulfated galactans proceeds through UDP galactose, a major nucleotide sugar in red seaweed, whilst sulfate is transported through S-transporters into algae. Moreover, synthesis of ethylene, a volatile plant growth regulator that plays an important role in red seaweed reproduction, occurs through S-adenosyl methionine. This means that sulfur metabolism is involved in reproduction events as well as sulfated galactan synthesis of red seaweed. In this work we study the effects of methionine and MgSO on gene expression of polygalactan synthesis through phosphoglucomutase (PGM) and galactose 1 phosphate uridyltransferase (GALT) and of sulfate assimilation (S-transporter and sulfate adenylyltransferase, SAT) using treatment of ethylene for 15 min, which elicited cystocarp development in . Also, expressions of and in charge of the addition and removal of sulfate groups to galactans backbone were examined. Outstanding results occurred in the presence of methionine, which provoked an increment in transcript number of genes encoding S-transporter and assimilation compared to controls regardless of the development stage of thalli. Otherwise, methionine diminished the transcript levels of and and expressions are associated with the fertilization stage of thalli of . As opposite, methionine and MgSO did not affect the transcript number of and . Nonetheless, differential expression was obtained for sulfurylases according to the development stages of thalli of .
Topics: Carrageenan; Ethylenes; Galactans; Galactose; Methionine; Rhodophyta; Seaweed; Sulfate Adenylyltransferase; Sulfates
PubMed: 35877729
DOI: 10.3390/md20070436 -
MBio Aug 2022The reactions of α-d-phosphohexomutases (αPHM) are ubiquitous, key to primary metabolism, and essential for several processes in all domains of life. The functionality...
The reactions of α-d-phosphohexomutases (αPHM) are ubiquitous, key to primary metabolism, and essential for several processes in all domains of life. The functionality of these enzymes relies on an initial phosphorylation step which requires the presence of α-d-glucose-1,6-bisphosphate (Glc-1,6-BP). While well investigated in vertebrates, the origin of this activator compound in bacteria is unknown. Here we show that the Slr1334 protein from the unicellular cyanobacterium sp. PCC 6803 is a Glc-1,6-BP-synthase. Biochemical analysis revealed that Slr1334 efficiently converts fructose-1,6-bisphosphate (Frc-1,6-BP) and α-d-glucose-1-phosphate/α-d-glucose-6-phosphate into Glc-1,6-BP and also catalyzes the reverse reaction. As inferred from phylogenetic analysis, the product belongs to a primordial subfamily of αPHMs that is present especially in deeply branching bacteria and also includes human commensals and pathogens. Remarkably, the homologue of Slr1334 in the human gut bacterium Bacteroides salyersiae catalyzes the same reaction, suggesting a conserved and essential role for the members of this αPHM subfamily. Glc-1,6-BP is known as an essential activator of phosphoglucomutase (PGM) and other members of the αPHM superfamily, making it a central regulator in glycogen metabolism, glycolysis, amino sugar formation as well as bacterial cell wall and capsule formation. Despite this essential role in carbon metabolism, its origin in prokaryotes has so far remained elusive. In this study we identify a member of a specific αPHM subfamily as the first bacterial Glc-1,6-BP synthase, forming free Glc-1,6-BP by using Frc-1,6-BP as phosphoryl-donor. PGMs of this subfamily are widely distributed among prokaryotes including human commensals and pathogens. By showing that a distinct subfamily member can also form Glc-1,6-BP, we provide evidence that Glc-1,6-BP synthase activity is a general feature of this group.
Topics: Animals; Glucose; Glucose-6-Phosphate; Humans; Phosphoglucomutase; Phylogeny
PubMed: 35856562
DOI: 10.1128/mbio.01469-22 -
Current Biology : CB Aug 2022All photosynthetic organisms balance CO assimilation with growth and carbon storage. Stored carbon is used for growth at night and when demand exceeds assimilation....
All photosynthetic organisms balance CO assimilation with growth and carbon storage. Stored carbon is used for growth at night and when demand exceeds assimilation. Gaining a mechanistic understanding of carbon partitioning between storage and growth in trees is important for biological studies and for estimating the potential of terrestrial photosynthesis to sequester anthropogenic CO emissions. Starch represents the main carbon storage in plants. To examine the carbon storage mechanism and role of starch during tree growth, we generated and characterized low-starch hybrid aspen (Populus tremula × tremuloides) trees using CRISPR-Cas9-mediated gene editing of two PHOSPHOGLUCOMUTASE (PGM) genes coding for plastidial PGM isoforms essential for starch biosynthesis. We demonstrate that starch deficiency does not reduce tree growth even in short days, showing that starch is not a critical carbon reserve during diel growth of aspen. The low-starch trees assimilated up to ∼30% less CO compared to the wild type under a range of irradiance levels, but this did not reduce growth or wood density. This implies that aspen growth is not limited by carbon assimilation under benign growth conditions. Moreover, the timing of bud set and bud flush in the low-starch trees was not altered, implying that starch reserves are not critical for the seasonal growth-dormancy cycle. The findings are consistent with a passive starch storage mechanism that contrasts with the annual Arabidopsis and indicate that the capacity of the aspen to absorb CO is limited by the rate of sink tissue growth.
Topics: Arabidopsis; Carbon; Carbon Dioxide; Photosynthesis; Plant Leaves; Populus; Starch
PubMed: 35820419
DOI: 10.1016/j.cub.2022.06.056 -
Discover Oncology Jul 2022Prostate cancer (PCa) is the most common malignancy in men in developed countries. Prostate-specific antigen (PSA) remains the most widely used serum marker for prostate...
Prostate cancer (PCa) is the most common malignancy in men in developed countries. Prostate-specific antigen (PSA) remains the most widely used serum marker for prostate cancer. Here, we reported that the expression of phosphoglucomutase-like protein 5 (PGM5) is significantly lower in prostate cancer tissue. The low expression of PGM5 and its related gene signature were found to be linked to poor clinical outcome and high Gleason score. In vitro assays showed that overexpression of PGM5 significantly repressed proliferation and migration of prostate cancer cells. GO and pathway analyses showed the enrichment of genes in regulation of cell growth and migration, and pathways related in cancer. Our additional results showed that the downregulation of PGM5 is closely related to DNA methylation. Taken together, our findings provide the first evidence that PGM5 expression is associated with prostate cancer progression. These results also highlight a preclinical rationale that PGM5 represents a prognostic marker and a promising target for new therapeutic strategies in prostate cancer.
PubMed: 35819729
DOI: 10.1007/s12672-022-00525-x -
Frontiers in Cellular and Infection... 2022The obligate intracellular bacteria store glycogen in the lumen of the vacuoles in which they grow. Glycogen catabolism generates glucose-1-phosphate (Glc1P), while the...
The obligate intracellular bacteria store glycogen in the lumen of the vacuoles in which they grow. Glycogen catabolism generates glucose-1-phosphate (Glc1P), while the bacteria can take up only glucose-6-phosphate (Glc6P). We tested whether the conversion of Glc1P into Glc6P could be catalyzed by a phosphoglucomutase (PGM) of host or bacterial origin. We found no evidence for the presence of the host PGM in the vacuole. Two proteins, CT295 and CT815, are potential PGMs. By reconstituting the reaction using purified proteins, and by complementing PGM deficient fibroblasts, we demonstrated that only CT295 displayed robust PGM activity. Intriguingly, we showed that glycogen accumulation in the lumen of the vacuole of a subset of species (, , ) correlated with the presence, in CT295 orthologs, of a secretion signal recognized by the type three secretion (T3S) machinery of . and do not accumulate glycogen, and their CT295 orthologs lack T3S signals. In conclusion, we established that the conversion of Glc1P into Glc6P was accomplished by a bacterial PGM, through the acquisition of a T3S signal in a "housekeeping" protein. Acquisition of this signal likely contributed to shaping glycogen metabolism within .
Topics: Chlamydia trachomatis; Glucose-6-Phosphate; Glycogen; Phosphoglucomutase; Vacuoles
PubMed: 35795184
DOI: 10.3389/fcimb.2022.866729 -
Biodesign Research 2022Maltose is a natural -(1,4)-linked disaccharide with wide applications in food industries and microbial fermentation. However, maltose has scarcely been used for...
Maltose is a natural -(1,4)-linked disaccharide with wide applications in food industries and microbial fermentation. However, maltose has scarcely been used for biosynthesis, possibly because its phosphorylation by maltose phosphorylase (MP) yields -glucose 1-phosphate (-G1P) that cannot be utilized by -phosphoglucomutase (-PGM) commonly found in synthetic enzymatic biosystems previously constructed by our group. Herein, we designed an synthetic enzymatic reaction module comprised of MP, -phosphoglucomutase (-PGM), and polyphosphate glucokinase (PPGK) for the stoichiometric conversion of each maltose molecule to two glucose 6-phosphate (G6P) molecules. Based on this synthetic module, we further constructed two synthetic biosystems to produce bioelectricity and fructose 1,6-diphosphate (FDP), respectively. The 14-enzyme biobattery achieved a Faraday efficiency of 96.4% and a maximal power density of 0.6 mW/cm, whereas the 5-enzyme FDP-producing biosystem yielded 187.0 mM FDP from 50 g/L (139 mM) maltose by adopting a fed-batch substrate feeding strategy. Our study not only suggests new application scenarios for maltose but also provides novel strategies for the high-efficient production of bioelectricity and value-added biochemicals.
PubMed: 37850132
DOI: 10.34133/2022/9806749