CTP synthase forms cytoophidia in archaea

AbstractCTP synthase (CTPS) is an important metabolic enzyme that catalyzes the rate-limiting reaction of de novo synthesis of the nucleotide CTP. Since 2010, a series of studies have demonstrated that CTPS can form filamentous structures termed cytoophidia in bacteria and eukaryotes. However, it remains unknown whether cytoophidia exist in archaea, the third domain of life. Using Haloarcula hispanica as a model system, here we demonstrate that CTPS forms distinct intracellular compartments in archaeal cells. Under stimulated emission depletion (STED) microscopy, we find that some HhCTPS compartments have elongated filamentous structures, resembling cytoophidia in bacteria and eukaryotes. When Haloarcula cells are cultured in low-salt medium, the occurrence of cytoophidia increases dramatically. Moreover, overexpression of CTPS or glutamine analog treatment promotes cytoophidium assembly in H. hispanica. Our study reveals that CTPS forms cytoophidia in all three domains of life, suggesting that this is an ancient property of CTPS.

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CTP synthase does not form cytoophidia in Drosophila interfollicular stalks

10.1101/2021.12.02.470862 ◽

2021 ◽

Author(s):

Zheng Wu ◽

Ji-Long Liu

Keyword(s):

De Novo ◽

In Vivo Study ◽

Follicle Cells ◽

De Novo Synthesis ◽

Ctp Synthase ◽

Domains Of Life ◽

Different Populations ◽

Germline Cells

ABSTRACTCTP synthase (CTPS) catalyzes the final step of de novo synthesis of the nucleotide CTP. In 2010, CTPS has been found to form filamentous structures termed cytoophidia in Drosophila follicle cells and germline cells. Subsequently, cytoophidia have been reported in many species across three domains of life: bacteria, eukaryotes and archaea. Forming cytoophidia appears to be a highly conserved and ancient property of CTPS. To our surprise, here we find that polar cells and stalk cells, two specialized types of cells composing Drosophila interfollicular stalks, do not possess obvious cytoophidia. Moreover, we show that Myc level is low in these two types of cells, supporting the idea that Myc regulates cytoophidium assembly. Treatment with a glutamine analog, 6-diazo-5-oxo-l-norleucine (DON), increases cytoophidium assembly in main follicle cells, but not in polar cells or stalk cells. Our findings provide an interesting paradigm for the in vivo study of cytoophidium assembly and disassembly among different populations of follicle cells.

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Inhibition of IMP Dehydrogenase by Mycophenolic Acid in Molt F4 Human Malignant Lymphoblasts

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456329403100211 ◽

1994 ◽

Vol 31 (2) ◽

pp. 174-180 ◽

Cited By ~ 11

Author(s):

Elisabet H Stet ◽

Ronney A De Abreu ◽

Jos P M Bökkerink ◽

Lambert H J Lambooy ◽

Trade M Vogels-Mentink ◽

...

Keyword(s):

Enzyme Activity ◽

Cell Growth ◽

Mycophenolic Acid ◽

De Novo ◽

Specific Inhibitor ◽

Guanine Nucleotides ◽

Guanine Nucleotide ◽

Inosine Monophosphate Dehydrogenase ◽

De Novo Synthesis ◽

Rate Limiting

The effects of inhibition of inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme in guanine nucleotide de novo synthesis, on cell growth, cell viability, endogenous nucleotide concentrations and concentrations of extracellular nucleosides and bases were studied in Molt F4 human malignant lymphoblasts. Mycophenolic acid (MPA) was used as a specific inhibitor of the enzyme activity. IMPDH activity was maximally inhibited with 0–5 μM MPA. After a 2 h exposure of the cells to 0–5 μM MPA, guanine nucleotides were depleted to approximately 50% of control values, whereas 5-phosphoribosyl-1-pyrophosphate levels increased to approximately 200%. Under these conditions, cytotoxicity became obvious after 24 h. Depletion of guanine nucleotides and cytotoxicity were prevented by addition of guanosine to MPA treatment. Daily supplements of guanosine were required to prevent MPA cytotoxicity during the entire incubation period of 72 h. We conclude that depletion of guanine nucleotides, induced by treatment with MPA, induces a severe and rapid cytotoxicity in Molt F4 cells.

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CcpC-Dependent Regulation of Citrate Synthase Gene Expression in Listeria monocytogenes

Journal of Bacteriology ◽

10.1128/jb.01384-08 ◽

2008 ◽

Vol 191 (3) ◽

pp. 862-872 ◽

Cited By ~ 5

Author(s):

Meghna Mittal ◽

Silvia Picossi ◽

Abraham L. Sonenshein

Keyword(s):

Listeria Monocytogenes ◽

Citrate Synthase ◽

De Novo ◽

Krebs Cycle ◽

Proximal Promoter ◽

De Novo Synthesis ◽

Distal Promoter ◽

Rate Limiting

ABSTRACT Citrate synthase, the first and rate-limiting enzyme of the tricarboxylic acid branch of the Krebs cycle, was shown to be required for de novo synthesis of glutamate and glutamine in Listeria monocytogenes. The citrate synthase (citZ) gene was found to be part of a complex operon with the upstream genes lmo1569 and lmo1568. The downstream isocitrate dehydrogenase (citC) gene appears to be part of the same operon as well. Two promoters were shown to drive citZ expression, a distal promoter located upstream of lmo1569 and a proximal promoter located upstream of the lmo1568 gene. Transcription of citZ from both promoters was regulated by CcpC by interaction with a single site; assays of transcription in vivo and assays of CcpC binding in vitro revealed that CcpC interacts with and represses the proximal promoter that drives expression of the lmo1568, citZ, and citC genes and, by binding to the same site, prevents read-through transcription from the distal, lmo1569 promoter. Expression of the lmo1568 operon was not affected by the carbon source but was repressed during growth in complex medium by addition of glutamine.

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Ubiquitination regulates cytoophidium assembly in Schizosaccharomyces pombe

10.1101/2021.12.06.470909 ◽

2021 ◽

Author(s):

Christos Andreadis ◽

Tianhao Li ◽

Ji-Long Liu

Keyword(s):

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

De Novo ◽

Metabolic Enzyme ◽

Filamentous Structure ◽

Deubiquitinating Enzymes ◽

Evolutionarily Conserved ◽

Ctp Synthase

AbstractCTP synthase (CTPS), a metabolic enzyme responsible for the de novo synthesis of CTP, can form filamentous structures termed cytoophidia, which are evolutionarily conserved from bacteria to humans. Here we used Schizosaccharomyces pombe to study the cytoophidium assembly regulation by ubiquitination. We tested the CTP synthase’s capacity to be epigenetically modified by ubiquitin or be affected by the ubiquitination state of the cell, showed that CTPS is immunoprecipitated with ubiquitin, and that ubiquitination is important for the maintenance of the CTPS filamentous structure in fission yeast. We have identified proteins which are in complex with CTPS, including specific ubiquitination regulators which significantly affect CTPS filamentation, and mapped probable ubiquitination targets on CTPS. Furthermore, we discovered that a cohort of deubiquitinating enzymes is significant for the regulation of cytoophidium morphology. Our study provides a framework for the analysis of the effects that ubiquitination and deubiquitination have on the formation of CTPS filaments.

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Characterization of Monocyte-Associated Factor V

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649565 ◽

1993 ◽

Vol 70 (02) ◽

pp. 273-280 ◽

Cited By ~ 5

Author(s):

Janos Kappelmayer ◽

Satya P Kunapuli ◽

Edward G Wyshock ◽

Robert W Colman

Keyword(s):

Monoclonal Antibody ◽

Light Chain ◽

Peripheral Blood ◽

De Novo ◽

Factor V ◽

Blood Monocytes ◽

De Novo Synthesis ◽

Hep G2 ◽

Hep G2 Cells ◽

Peripheral Blood Monocytes

SummaryWe demonstrate that in addition to possessing binding sites for intact factor V (FV), unstimulated peripheral blood monocytes also express activated factor V (FVa) on their surfaces. FVa was identified on the monocyte surface by monoclonal antibody B38 recognizing FVa light chain and by human oligoclonal antibodies H1 (to FVa light chain) and H2 (to FVa heavy chain) using immunofluorescence microscopy and flow cytometry. On Western blots, partially cleaved FV could be identified as a 220 kDa band in lysates of monocytes. In addition to surface expression of FVa, monocytes also contain intracellular FV as detected only after permeabilization by Triton X-100 by monoclonal antibody B10 directed specifically to the Cl domain not present in FVa. We sought to determine whether the presence of FV in peripheral blood monocytes is a result of de novo synthesis.Using in situ hybridization, no FV mRNA could be detected in monocytes, while in parallel control studies, factor V mRNA was detectable in Hep G2 cells and CD18 mRNA in monocytes. In addition, using reverse transcriptase and the polymerase chain reaction, no FV mRNA was detected in mononuclear cells or in U937 cells, but mRNA for factor V was present in Hep G2 cells using the same techniques. These data suggest that FV is present in human monocytes, presumably acquired by binding of plasma FV, and that the presence of this critical coagulation factor is not due to de novo synthesis.

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Platelets Stimulate Thromboplastin Synthesis in Human Endothelial Cells

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657323 ◽

1983 ◽

Vol 49 (02) ◽

pp. 069-072 ◽

Cited By ~ 20

Author(s):

U L H Johnsen ◽

T Lyberg ◽

K S Galdal ◽

H Prydz

Keyword(s):

Endothelial Cells ◽

De Novo ◽

Umbilical Vein ◽

Time Dependent ◽

De Novo Synthesis ◽

Human Endothelial Cells ◽

Tumor Promotor ◽

Coagulation Assay ◽

Platelet Aggregates ◽

Umbilical Vein Endothelial Cells

SummaryHuman umbilical vein endothelial cells in culture synthesize thromboplastin upon stimulation with phytohaemagglutinin (PHA) or the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The thromboplastin activity is further strongly enhanced in a time dependent reaction by the presence of gel-filtered platelets or platelet aggregates. This effect was demonstrable at platelet concentrations lower than those normally found in plasma, it may thus be of pathophysiological relevance. The thromboplastin activity increased with increasing number of platelets added. Cycloheximide inhibited the increase, suggesting that de novo synthesis of the protein component of thromboplastin, apoprotein III, is necessary.When care was taken to remove monocytes no thromboplastin activity and no apoprotein HI antigen could be demonstrated in suspensions of gel-filtered platelets, platelets aggregated with thrombin or homogenized platelets when studied with a coagulation assay and an antibody neutralization technique.

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