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Science (New York, N.Y.) Feb 2013The presence of DNA in the cytoplasm of mammalian cells is a danger signal that triggers host immune responses such as the production of type I interferons. Cytosolic...
The presence of DNA in the cytoplasm of mammalian cells is a danger signal that triggers host immune responses such as the production of type I interferons. Cytosolic DNA induces interferons through the production of cyclic guanosine monophosphate-adenosine monophosphate (cyclic GMP-AMP, or cGAMP), which binds to and activates the adaptor protein STING. Through biochemical fractionation and quantitative mass spectrometry, we identified a cGAMP synthase (cGAS), which belongs to the nucleotidyltransferase family. Overexpression of cGAS activated the transcription factor IRF3 and induced interferon-β in a STING-dependent manner. Knockdown of cGAS inhibited IRF3 activation and interferon-β induction by DNA transfection or DNA virus infection. cGAS bound to DNA in the cytoplasm and catalyzed cGAMP synthesis. These results indicate that cGAS is a cytosolic DNA sensor that induces interferons by producing the second messenger cGAMP.
Topics: Adenosine Triphosphate; Amino Acid Sequence; Animals; Cell Line, Tumor; Cyclic AMP; Cyclic GMP; Cytidine Triphosphate; Cytosol; DNA; Gene Knockdown Techniques; HEK293 Cells; Humans; Interferon Type I; Interferon-beta; Metabolic Networks and Pathways; Mice; Molecular Sequence Data; Nucleotidyltransferases
PubMed: 23258413
DOI: 10.1126/science.1232458 -
Journal of the American Academy of... Aug 2022Janus kinase (JAK) activation is suggested to have a pathological role in alopecia areata (AA). CTP-543, a deuterated compound that selectively inhibits JAK1 and JAK2,... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Janus kinase (JAK) activation is suggested to have a pathological role in alopecia areata (AA). CTP-543, a deuterated compound that selectively inhibits JAK1 and JAK2, is being developed as an oral treatment for AA.
OBJECTIVE
To assess the safety and efficacy of a 24-week regimen of CTP-543 in patients with chronic, moderate-to-severe AA.
METHODS
In this phase 2, randomized, double-blind, placebo-controlled, sequential-design trial, patients were randomized to receive CTP-543 (4 mg, 8 mg, or 12 mg) or placebo every 12 hours for 24 weeks.
RESULTS
A dose-related increase was observed in the percentage of patients with ≥50% relative reduction in Severity of Alopecia Tool scores from baseline at week 24 (9% placebo, 21% 4 mg twice daily, 47% 8 mg twice daily, and 58% 12 mg twice daily), with statistical significance versus placebo (P < .001) observed for the 8-mg twice daily and 12-mg twice daily groups, with differences from placebo noted as early as 12 weeks after the initiation of treatment. Safety results were consistent with the known safety profiles of JAK inhibitors.
LIMITATIONS
These initial findings are from a relatively small controlled trial, and additional studies are needed to fully characterize the safety and efficacy of CTP-543 in adult patients with AA.
CONCLUSIONS
Patients treated with CTP-543 (8 or 12 mg, twice daily) had a significant reduction in the severity of AA.
Topics: Adult; Alopecia Areata; Cytidine Triphosphate; Humans; Janus Kinase Inhibitors; Pyrimidines; Treatment Outcome
PubMed: 35364216
DOI: 10.1016/j.jaad.2022.03.045 -
Annual Review of Virology Sep 2020Most cells respond to viral infections by activating innate immune pathways that lead to the induction of antiviral restriction factors. One such factor, viperin, was... (Review)
Review
Most cells respond to viral infections by activating innate immune pathways that lead to the induction of antiviral restriction factors. One such factor, viperin, was discovered almost two decades ago based on its induction during viral infection. Since then, viperin has been shown to possess activity against numerous viruses via multiple proposed mechanisms. Most recently, however, viperin was demonstrated to catalyze the conversion of cytidine triphosphate (CTP) to 3'-deoxy-3',4'-didehydro-CTP (ddhCTP), a previously unknown ribonucleotide. Incorporation of ddhCTP causes premature termination of RNA synthesis by the RNA-dependent RNA polymerase of some viruses. To date, production of ddhCTP by viperin represents the only activity of viperin that links its enzymatic activity directly to an antiviral mechanism in human cells. This review examines the multiple antiviral mechanisms and biological functions attributed to viperin.
Topics: Cytidine Triphosphate; Humans; Oxidoreductases Acting on CH-CH Group Donors; Proteins; RNA-Dependent RNA Polymerase; Virus Diseases
PubMed: 32603630
DOI: 10.1146/annurev-virology-011720-095930 -
Journal of Translational Medicine Jan 2022Cytidine nucleotide triphosphate synthase 1 (CTPS1) is a CTP synthase which play critical roles in DNA synthesis. However, its biological regulation and mechanism in...
BACKGROUND
Cytidine nucleotide triphosphate synthase 1 (CTPS1) is a CTP synthase which play critical roles in DNA synthesis. However, its biological regulation and mechanism in triple-negative breast cancer (TNBC) has not been reported yet.
METHODS
The expression of CTPS1 in TNBC tissues was determined by GEO, TCGA databases and immunohistochemistry (IHC). The effect of CTPS1 on TNBC cell proliferation, migration, invasion, apoptosis and tumorigenesis were explored in vivo and in vitro. In addition, the transcription factor Y-box binding protein 1 (YBX1) was identified by bioinformatics methods, dual luciferase reporter and chromatin immunoprecipitation (CHIP) assays. Pearson correlation analysis was utilized to assess the association between YBX1 and CTPS1 expression.
RESULTS
CTPS1 expression was significantly upregulated in TNBC tissues and cell lines. Higher CTPS1 expression was correlated with a poorer disease-free survival (DFS) and overall survival (OS) in TNBC patients. Silencing of CTPS1 dramatically inhibited the proliferation, migration, invasion ability and induced apoptosis of MDA-MB-231 and HCC1937 cells. Xenograft tumor model also indicated that CTPS1 knockdown remarkably reduced tumor growth in mice. Mechanically, YBX1 could bind to the promoter of CTPS1 to promote its transcription. Furthermore, the expression of YBX1 was positively correlated with CTPS1 in TNBC tissues. Rescue experiments confirmed that the enhanced cell proliferation and invasion ability induced by YBX1 overexpression could be reversed by CTPS1 knockdown.
CONCLUSION
Our data demonstrate that YBX1/CTPS1 axis plays an important role in the progression of TNBC. CTPS1 might be a promising prognosis biomarker and potential therapeutic target for patients with triple-negative breast cancer.
Topics: Animals; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cytidine Triphosphate; Gene Expression Regulation, Neoplastic; Humans; Mice; Nucleotides; Transcriptional Activation; Triple Negative Breast Neoplasms; Y-Box-Binding Protein 1
PubMed: 34991621
DOI: 10.1186/s12967-021-03206-5 -
Nature Communications Mar 2024De novo synthesis of the pyrimidine, cytidine triphosphate (CTP), is crucial for DNA/RNA metabolism and depends on the CTP synthetases, CTPS1 and -2. Partial CTPS1...
De novo synthesis of the pyrimidine, cytidine triphosphate (CTP), is crucial for DNA/RNA metabolism and depends on the CTP synthetases, CTPS1 and -2. Partial CTPS1 deficiency in humans has previously been shown to lead to immunodeficiency, with impaired expansion of T and B cells. Here, we examine the effects of conditional and inducible inactivation of Ctps1 and/or Ctps2 on mouse embryonic development and immunity. We report that deletion of Ctps1, but not Ctps2, is embryonic-lethal. Tissue and cells with high proliferation and renewal rates, such as intestinal epithelium, erythroid and thymic lineages, activated B and T lymphocytes, and memory T cells strongly rely on CTPS1 for their maintenance and growth. However, both CTPS1 and CTPS2 are required for T cell proliferation following TCR stimulation. Deletion of Ctps1 in T cells or treatment with a CTPS1 inhibitor rescued Foxp3-deficient mice from fatal systemic autoimmunity and reduced the severity of experimental autoimmune encephalomyelitis. These findings support that CTPS1 may represent a target for immune suppression.
Topics: Female; Pregnancy; Humans; Animals; Mice; Cytidine Triphosphate; Embryonic Development; Autoimmunity; B-Lymphocytes; Cell Proliferation
PubMed: 38438357
DOI: 10.1038/s41467-024-45805-y -
ACS Bio & Med Chem Au Aug 20233'-Deoxy-3',4'-didehydro-cytidine triphosphate (ddhCTP) is a novel antiviral molecule produced by the enzyme viperin during the early stages of the innate immune...
3'-Deoxy-3',4'-didehydro-cytidine triphosphate (ddhCTP) is a novel antiviral molecule produced by the enzyme viperin during the early stages of the innate immune response. ddhCTP has been shown to act as a chain terminator of flavivirus RNA-dependent RNA polymerases. To date, synthesis of ddhCTP requires complicated synthetic protocols or isolation of the enzyme viperin to catalyze the production of ddhCTP from CTP. Recombinant viperin approaches preclude the production of highly pure ddhCTP (free of contaminants such as CTP), whereas the chemical synthesis involves techniques or equipment not readily available to most laboratories. Herein, we describe the chemoenzymatic synthesis of ddhCTP, starting from commercially available ddhC. We utilize these methods to produce milligram quantities of ddhCTP, ddhCDP, and ddhCMP. Using purified semisynthetic ddhCTP and fully synthetic ddhCTP, we also show ddhCTP does not inhibit NAD-dependent enzymes such as glyceraldehyde 3-phosphate dehydrogenase, malate dehydrogenase, or lactate dehydrogenase, contrary to a recent report.
PubMed: 37599790
DOI: 10.1021/acsbiomedchemau.3c00014 -
Current Opinion in Microbiology Jun 2023Segregation of genetic material is a fundamental process in biology. In many bacterial species, segregation of chromosomes and low-copy plasmids is facilitated by the... (Review)
Review
Segregation of genetic material is a fundamental process in biology. In many bacterial species, segregation of chromosomes and low-copy plasmids is facilitated by the tripartite ParA-ParB-parS system. This system consists of a centromeric parS DNA site and interacting proteins ParA and ParB that are capable of hydrolyzing adenosine triphosphate and cytidine triphosphate (CTP), respectively. ParB first binds to parS before associating with adjacent DNA regions to spread outward from parS. These ParB-DNA complexes bind to ParA and, through repetitive cycles of ParA-ParB binding and unbinding, move the DNA cargo to each daughter cell. The recent discovery that ParB binds and hydrolyzes CTP as it cycles on and off the bacterial chromosome has dramatically changed our understanding of the molecular mechanism used by the ParABS system. Beyond bacterial chromosome segregation, CTP-dependent molecular switches are likely to be more widespread in biology than previously appreciated and represent an opportunity for new and unexpected avenues for future research and application.
Topics: Bacterial Proteins; Chromosome Segregation; Plasmids; DNA, Bacterial; Chromosomes, Bacterial
PubMed: 36871427
DOI: 10.1016/j.mib.2023.102289 -
Frontiers in Plant Science 2022Cytidine triphosphate synthase (CTPS) catalyzes the final step in pyrimidine synthesis. In Arabidopsis, this protein family consists of five members (CTPS1-5), and all...
Cytidine triphosphate synthase (CTPS) catalyzes the final step in pyrimidine synthesis. In Arabidopsis, this protein family consists of five members (CTPS1-5), and all of them localize to the cytosol. Specifically, showed a massive upregulation of transcript levels during abiotic stress, in line with increased staining of promoter:GUS lines in hypocotyl, root and to lesser extend leaf tissues. In a setup to study progressive drought stress, knockout mutants accumulated less fresh and dry weight at days 5-7 and showed impaired ability to recover from this stress after 3 days of rewatering. Surprisingly, a thorough physiological characterization of corresponding plants only revealed alterations in assimilation and accumulation of soluble sugars including those related to drought stress in the mutant. Bimolecular fluorescence complementation (BiFC) studies indicated the interaction of CTPS4 with other isoforms, possibly affecting cytoophidia (filaments formed by CTPS formation. Although the function of these structures has not been thoroughly investigated in plants, altered enzyme activity and effects on cell structure are reported in other organisms. CTPS activity is required for cell cycle progression and growth. Furthermore, drought can lead to the accumulation of reactive oxygen species (ROS) and by this, to DNA damage. We hypothesize that effects on the cell cycle or DNA repair might be relevant for the observed impaired reduced drought stress tolerance of mutants.
PubMed: 35360303
DOI: 10.3389/fpls.2022.842156 -
Journal of Molecular Biology Jan 2022The ParABS system is supposed to be responsible for plasmid partitioning and chromosome segregation in bacteria. ParABS ensures a high degree of fidelity in inheritance...
The ParABS system is supposed to be responsible for plasmid partitioning and chromosome segregation in bacteria. ParABS ensures a high degree of fidelity in inheritance by dividing the genetic material equally between daughter cells during cell division. However, the molecular mechanisms underlying the assembly of the partition complex, representing the core of the ParABS system, are still far from being understood. Here we demonstrate that the partition complex is formed via liquid-liquid phase separation. Assembly of the partition complex is initiated by the formation of oligomeric ParB species, which in turn are regulated by CTP-binding. Phase diagrams and in vivo analysis show how the partition complex can further be spatially regulated by parS. By investigating the phylogenetic variation in phase separation and its regulation by CTP, we find a high degree of evolutionary conservation among distantly related prokaryotes. These results advance the understanding of partition complex formation and regulation in general, by confirming and extending recently proposed models.
Topics: Bacteria; Bacterial Physiological Phenomena; Bacterial Proteins; Cell Division; Chromosome Segregation; Chromosomes, Bacterial; Corynebacterium glutamicum; Cytidine Triphosphate; DNA Primase; DNA, Bacterial; Phase Transition; Phylogeny
PubMed: 34902429
DOI: 10.1016/j.jmb.2021.167401 -
Fly Jul 2016Living organisms respond to nutrient availability by regulating the activity of metabolic enzymes. Therefore, the reversible post-translational modification of an enzyme...
Living organisms respond to nutrient availability by regulating the activity of metabolic enzymes. Therefore, the reversible post-translational modification of an enzyme is a common regulatory mechanism for energy conservation. Recently, cytidine-5'-triphosphate (CTP) synthase was discovered to form a filamentous structure that is evolutionarily conserved from flies to humans. Interestingly, induction of the formation of CTP synthase filament is responsive to starvation or glutamine depletion. However, the biological roles of this structure remain elusive. We have recently shown that ubiquitination regulates CTP synthase activity by promoting filament formation in Drosophila ovaries during endocycles. Intriguingly, although the ubiquitination process was required for filament formation induced by glutamine depletion, CTP synthase ubiquitination was found to be inversely correlated with filament formation in Drosophila and human cell lines. In this article, we discuss the putative dual roles of ubiquitination, as well as its physiological implications, in the regulation of CTP synthase structure.
Topics: Animals; Carbon-Nitrogen Ligases; Cytoskeleton; Drosophila; Female; Glutamine; Ovary; Protein Processing, Post-Translational; Ubiquitination
PubMed: 27116391
DOI: 10.1080/19336934.2016.1182268