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Cell Jan 2020Mutations in FAMIN cause arthritis and inflammatory bowel disease in early childhood, and a common genetic variant increases the risk for Crohn's disease and leprosy. We...
Mutations in FAMIN cause arthritis and inflammatory bowel disease in early childhood, and a common genetic variant increases the risk for Crohn's disease and leprosy. We developed an unbiased liquid chromatography-mass spectrometry screen for enzymatic activity of this orphan protein. We report that FAMIN phosphorolytically cleaves adenosine into adenine and ribose-1-phosphate. Such activity was considered absent from eukaryotic metabolism. FAMIN and its prokaryotic orthologs additionally have adenosine deaminase, purine nucleoside phosphorylase, and S-methyl-5'-thioadenosine phosphorylase activity, hence, combine activities of the namesake enzymes of central purine metabolism. FAMIN enables in macrophages a purine nucleotide cycle (PNC) between adenosine and inosine monophosphate and adenylosuccinate, which consumes aspartate and releases fumarate in a manner involving fatty acid oxidation and ATP-citrate lyase activity. This macrophage PNC synchronizes mitochondrial activity with glycolysis by balancing electron transfer to mitochondria, thereby supporting glycolytic activity and promoting oxidative phosphorylation and mitochondrial H and phosphate recycling.
Topics: Adenine; Adenosine; Adenosine Deaminase; Chromatography, Liquid; HEK293 Cells; Hep G2 Cells; Humans; Intracellular Signaling Peptides and Proteins; Mass Spectrometry; Multifunctional Enzymes; Phosphorylation; Proteins; Purine Nucleotides; Purines
PubMed: 31978345
DOI: 10.1016/j.cell.2019.12.017 -
Cell Metabolism Feb 2017During immune challenge, T lymphocytes engage pathways of anabolic metabolism to support clonal expansion and the development of effector functions. Here we report a...
During immune challenge, T lymphocytes engage pathways of anabolic metabolism to support clonal expansion and the development of effector functions. Here we report a critical role for the non-essential amino acid serine in effector T cell responses. Upon activation, T cells upregulate enzymes of the serine, glycine, one-carbon (SGOC) metabolic network, and rapidly increase processing of serine into one-carbon metabolism. We show that extracellular serine is required for optimal T cell expansion even in glucose concentrations sufficient to support T cell activation, bioenergetics, and effector function. Restricting dietary serine impairs pathogen-driven expansion of T cells in vivo, without affecting overall immune cell homeostasis. Mechanistically, serine supplies glycine and one-carbon units for de novo nucleotide biosynthesis in proliferating T cells, and one-carbon units from formate can rescue T cells from serine deprivation. Our data implicate serine as a key immunometabolite that directly modulates adaptive immunity by controlling T cell proliferative capacity.
Topics: Animals; Carbon; Cell Cycle Checkpoints; Cell Proliferation; Diet; Energy Metabolism; Extracellular Space; Glycine; Listeria monocytogenes; Metabolic Networks and Pathways; Metabolome; Mice, Inbred C57BL; Purine Nucleotides; Serine; T-Lymphocytes
PubMed: 28111214
DOI: 10.1016/j.cmet.2016.12.011 -
International Journal of Molecular... Jun 2021Huntington's disease (HD) is a multi-system disorder that is caused by expanded CAG repeats within the exon-1 of the huntingtin () gene that translate to the... (Review)
Review
Huntington's disease (HD) is a multi-system disorder that is caused by expanded CAG repeats within the exon-1 of the huntingtin () gene that translate to the polyglutamine stretch in the HTT protein. HTT interacts with the proteins involved in gene transcription, endocytosis, and metabolism. HTT may also directly or indirectly affect purine metabolism and signaling. We aimed to review existing data and discuss the modulation of the purinergic system as a new therapeutic target in HD. Impaired intracellular nucleotide metabolism in the HD affected system (CNS, skeletal muscle and heart) may lead to extracellular accumulation of purine metabolites, its unusual catabolism, and modulation of purinergic signaling. The mechanisms of observed changes might be different in affected systems. Based on collected findings, compounds leading to purine and ATP pool reconstruction as well as purinergic receptor activity modulators, i.e., P2X7 receptor antagonists, may be applied for HD treatment.
Topics: AMP Deaminase; Animals; Enzyme Inhibitors; Humans; Huntingtin Protein; Huntington Disease; Neuroprotective Agents; Purine Nucleotides; Signal Transduction
PubMed: 34207177
DOI: 10.3390/ijms22126545 -
Cold Spring Harbor Perspectives in... Jul 2021
Review
Topics: Animals; Humans; Nucleosides; Purine Nucleotides; Pyrimidine Nucleotides; Signal Transduction
PubMed: 34210662
DOI: 10.1101/cshperspect.a040592 -
Frontiers in Immunology 2019Purine nucleotides and nucleosides are at the center of biologic reactions. In particular, adenosine triphosphate (ATP) is the fundamental energy currency of cellular... (Review)
Review
Purine nucleotides and nucleosides are at the center of biologic reactions. In particular, adenosine triphosphate (ATP) is the fundamental energy currency of cellular activity and adenosine has been demonstrated to play essential roles in human physiology and pathophysiology. In this review, we examine the role of purinergic signaling in acute and chronic pulmonary inflammation, with emphasis on ATP and adenosine. ATP is released into extracellular space in response to cellular injury and necrosis. It is then metabolized to adenosine monophosphate (AMP) via ectonucleoside triphosphate diphosphohydrolase-1 (CD39) and further hydrolyzed to adenosine via ecto-5'-nucleotidase (CD73). Adenosine signals via one of four adenosine receptors to exert pro- or anti-inflammatory effects. Adenosine signaling is terminated by intracellular transport by concentrative or equilibrative nucleoside transporters (CNTs and ENTs), deamination to inosine by adenosine deaminase (ADA), or phosphorylation back into AMP via adenosine kinase (AK). Pulmonary inflammatory and hypoxic conditions lead to increased extracellular ATP, adenosine diphosphate (ADP) and adenosine levels, which translates to increased adenosine signaling. Adenosine signaling is central to the pulmonary injury response, leading to various effects on inflammation, repair and remodeling processes that are either tissue-protective or tissue destructive. In the acute setting, particularly through activation of adenosine 2A and 2B receptors, adenosine signaling serves an anti-inflammatory, tissue-protective role. However, excessive adenosine signaling in the chronic setting promotes pro-inflammatory, tissue destructive effects in chronic pulmonary inflammation.
Topics: Adenosine Deaminase; Adenosine Monophosphate; Adenosine Triphosphate; Animals; Humans; Pneumonia; Purinergic Agents; Signal Transduction
PubMed: 31379836
DOI: 10.3389/fimmu.2019.01633 -
Nature Communications May 2022Purine nucleotides are necessary for various biological processes related to cell proliferation. Despite their importance in DNA and RNA synthesis, cellular signaling,...
Purine nucleotides are necessary for various biological processes related to cell proliferation. Despite their importance in DNA and RNA synthesis, cellular signaling, and energy-dependent reactions, the impact of changes in cellular purine levels on cell physiology remains poorly understood. Here, we find that purine depletion stimulates cell migration, despite effective reduction in cell proliferation. Blocking purine synthesis triggers a shunt of glycolytic carbon into the serine synthesis pathway, which is required for the induction of cell migration upon purine depletion. The stimulation of cell migration upon a reduction in intracellular purines required one-carbon metabolism downstream of de novo serine synthesis. Decreased purine abundance and the subsequent increase in serine synthesis triggers an epithelial-mesenchymal transition (EMT) and, in cancer models, promotes metastatic colonization. Thus, reducing the available pool of intracellular purines re-routes metabolic flux from glycolysis into de novo serine synthesis, a metabolic change that stimulates a program of cell migration.
Topics: Carbon; Cell Movement; Purine Nucleotides; Purines; Serine
PubMed: 35577785
DOI: 10.1038/s41467-022-30362-z -
Plant Signaling & Behavior Jan 2021Structural components of second messenger signaling (nucleotides and associated enzyme systems) within plant and animal cells have more in common than the hormones that...
Structural components of second messenger signaling (nucleotides and associated enzyme systems) within plant and animal cells have more in common than the hormones that initiate metabolic and functional changes. Neurotransmitters and hormones of mammalian pharmacologic classes relate to purine nucleotides in respect of chemical structure and the molecular changes they initiate. This study compares the molecular structures of purine nucleotides with compounds from the abscisic acid, auxin, brassinosteroid, cytokinin, gibberellin, and jasmonate classes by means of a computational program. The results illustrate how phytohomones relate to each other through the structures of nucleotides and cyclic nucleotides. Molecular similarity within the phytohormone structures relates to synergism, antagonism and the modulation of nucleotide function that regulates germination and plant development. As with the molecular evolution of mammalian hormones, cell signaling and cross-talk within the phytohormone classes is purine nucleotide centered.
Topics: Abscisic Acid; Cyclopentanes; Cytokinins; Gibberellins; Indoleacetic Acids; Oxylipins; Plant Growth Regulators; Purine Nucleotides; Signal Transduction
PubMed: 33100143
DOI: 10.1080/15592324.2020.1837544 -
Nature Communications May 2023Brown adipose tissue expresses uncoupling protein 1 (UCP1), which dissipates energy as heat, making it a target for treating metabolic disorders. Here, we investigate...
Brown adipose tissue expresses uncoupling protein 1 (UCP1), which dissipates energy as heat, making it a target for treating metabolic disorders. Here, we investigate how purine nucleotides inhibit respiration uncoupling by UCP1. Our molecular simulations predict that GDP and GTP bind UCP1 in the common substrate binding site in an upright orientation, where the base moiety interacts with conserved residues R92 and E191. We identify a triplet of uncharged residues, F88/I187/W281, forming hydrophobic contacts with nucleotides. In yeast spheroplast respiration assays, both I187A and W281A mutants increase the fatty acid-induced uncoupling activity of UCP1 and partially suppress the inhibition of UCP1 activity by nucleotides. The F88A/I187A/W281A triple mutant is overactivated by fatty acids even at high concentrations of purine nucleotides. In simulations, E191 and W281 interact with purine but not pyrimidine bases. These results provide a molecular understanding of the selective inhibition of UCP1 by purine nucleotides.
Topics: Ion Channels; Uncoupling Protein 1; Membrane Proteins; Mitochondrial Proteins; Fatty Acids; Purine Nucleotides; Adipose Tissue, Brown; Saccharomyces cerevisiae
PubMed: 37147287
DOI: 10.1038/s41467-023-38219-9 -
Purinergic Signalling Sep 2020Extracellular purine nucleotides and nucleosides including ADP and ATP regulate a wide array of physiological processes including platelet aggregation, vasomotor... (Review)
Review
Extracellular purine nucleotides and nucleosides including ADP and ATP regulate a wide array of physiological processes including platelet aggregation, vasomotor responses and inflammation through specific purinergic receptors. In the recent years, a strong association has been reported between circulating cytoplasmic-type creatine kinase and adverse clinical outcomes such as major bleeding, hypertension and obesity. Therefore, it is proposed that extracellular CK may modulate purinergic signalling through its ADP binding and/or ATP-generating effect.
Topics: Adenosine Diphosphate; Adenosine Triphosphate; Animals; Creatine Kinase; Humans; Receptors, Purinergic; Signal Transduction
PubMed: 32572751
DOI: 10.1007/s11302-020-09707-0 -
Biochemistry Sep 2023Because purine nucleotides are essential for all life, differences between how microbes and humans metabolize purines can be exploited for the development of...
Because purine nucleotides are essential for all life, differences between how microbes and humans metabolize purines can be exploited for the development of antimicrobial therapies. While humans biosynthesize purine nucleotides in a 10-step pathway, most microbes utilize an additional 11th enzymatic activity. The human enzyme, aminoimidazole ribonucleotide (AIR) carboxylase generates the product 4-carboxy-5-aminoimidazole ribonucleotide (CAIR) directly. Most microbes, however, require two separate enzymes, a synthetase (PurK) and a mutase (PurE), and proceed through the intermediate, N-CAIR. Toward the development of therapeutics that target these differences, we have solved crystal structures of the N-CAIR mutase of the human pathogens (LpPurE) and (BcPurE) and used a structure-guided approach to identify inhibitors. Analysis of the structures reveals a highly conserved fold and active site architecture. Using this data, and three additional structures of PurE enzymes, we screened a library of FDA-approved compounds and identified a set of 25 candidates for further analysis. Among these, we identified several new PurE inhibitors with micromolar IC values. Several of these compounds, including the α-blocker Alfuzosin, inhibit the microbial PurE enzymes much more effectively than the human homologue. These structures and the newly described PurE inhibitors are valuable tools to aid in further studies of this enzyme and provide a foundation for the development of compounds that target differences between human and microbial purine metabolism.
Topics: Humans; Ribonucleotides; Escherichia coli; Intramolecular Transferases; Purine Nucleotides
PubMed: 37552766
DOI: 10.1021/acs.biochem.2c00705