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Cell Calcium Sep 2022The transient receptor potential cation channel, subfamily M, members 6 and 7 (TRPM6 and TRPM7) are homologous membrane proteins encompassing cation channel units fused...
The transient receptor potential cation channel, subfamily M, members 6 and 7 (TRPM6 and TRPM7) are homologous membrane proteins encompassing cation channel units fused to cytosolic serine/threonine-protein kinase domains. Clinical studies and experiments with animal disease models suggested that selective inhibition of TRPM6 and TRPM7 currents might be beneficial for subjects with immune and cardiovascular disorders, tumours and other pathologies, but the suitable pharmacological toolkit remains underdeveloped. The present study identified small synthetic molecules acting specifically on the channel moieties of TRPM6 and TRPM7. Using electrophysiological analysis in conjunction with Ca imaging, we show that iloperidone and ifenprodil inhibit the channel activity of recombinant TRPM6 with IC values of 0.73 and 3.33 µM, respectively, without an impact on the TRPM7 channel. We also found that VER155008 suppresses the TRPM7 channel with an IC value of 0.11 µM but does not affect TRPM6. Finally, the effects of iloperidone and VER155008 were found to be suitable for blocking native endogenous TRPM6 and TRPM7 in a collection of mouse and human cell models. Hence, the identification of iloperidone, ifenprodil, and VER155008 allows for the first time to selectively manipulate TRPM6 and TRPM7 currents.
Topics: Animals; Humans; Isoxazoles; Magnesium; Mice; Piperidines; Protein Serine-Threonine Kinases; Purine Nucleosides; TRPM Cation Channels; Transient Receptor Potential Channels
PubMed: 36030694
DOI: 10.1016/j.ceca.2022.102640 -
Annals of Oncology : Official Journal... 1996In an area of lymphoma classification still being defined, marginal-zone lymphomas have distinctive immunohistochemical and cytogenetic features that distinguish them... (Review)
Review
In an area of lymphoma classification still being defined, marginal-zone lymphomas have distinctive immunohistochemical and cytogenetic features that distinguish them from mantle-cell and follicular lymphomas. There are three subtypes: the extranodal mucosa-associated lymphoid tissue (MALT) lymphomas, the nodal monocytoid B-cell (MBCL) lymphomas, and the splenic marginal-zone lymphomas. The MALT lymphomas represent the neoplastic counterpart of the gut-associated lymphoid tissue, which extends from the jejunum to the rectum. They arise in sites usually containing no lymphoid tissue, such as the stomach, thyroid, and salivary gland. Gastric MALT lymphomas, the most common, are associated with Helicobacter pylori. The MBCL lymphomas closely resemble MALT lymphomas and unlike other non-Hodgkin's lymphomas are commonly composite. Therapy for these lymphomas may include radiation therapy or surgery when disease is of limited extent. However, gastrectomy for gastric MALT lymphomas is not in favor because of the efficacy of antibiotic regimens that can eliminate H. pylori infection. Splenectomy may be indicated for splenic lymphomas. Purine analogs are promising therapeutic agents because they are specific for lymphoid cells. Also, they may prove useful in indolent cancers such as these, because of their activity against dividing and resting cells. Purine analogs may be considered as second-line therapy after alkylating agents for these lymphomas.
Topics: Antineoplastic Agents; Humans; Lymphoma, B-Cell; Lymphoma, B-Cell, Marginal Zone; Purine Nucleosides; Stomach Neoplasms
PubMed: 9010575
DOI: 10.1093/annonc/7.suppl_6.s21 -
Applied and Environmental Microbiology Nov 2018Purine nucleoside antibiotic pairs, concomitantly produced by a single strain, are an important group of microbial natural products. Here, we report a target-directed...
Purine nucleoside antibiotic pairs, concomitantly produced by a single strain, are an important group of microbial natural products. Here, we report a target-directed genome mining approach to elucidate the biosynthesis of the purine nucleoside antibiotic pair aristeromycin (ARM) and coformycin (COF) in DSM 45626 (a new producer for ARM and COF) and NBRC 13005 (a new COF producer). We also provide biochemical data that MacI and MacT function as unusual phosphorylases, catalyzing an irreversible reaction for the tailoring assembly of neplanocin A (NEP-A) and ARM. Moreover, we demonstrate that MacQ is shown to be an adenosine-specific deaminase, likely relieving the potential "excess adenosine" for producing cells. Finally, we report that MacR, an annotated IMP dehydrogenase, is actually an NADPH-dependent GMP reductase, which potentially plays a salvage role for the efficient supply of the precursor pool. Hence, these findings illustrate a fine-tuned pathway for the biosynthesis of ARM and also open the way for the rational search for purine antibiotic pairs. ARM and COF are well known for their prominent biological activities and unusual chemical structures; however, the logic of their biosynthesis has long been poorly understood. Actually, the new insights into the ARM and COF pathway will not only enrich the biochemical repertoire for interesting enzymatic reactions but may also lay a solid foundation for the combinatorial biosynthesis of this group of antibiotics via a target-directed genome mining strategy.
Topics: Actinobacteria; Adenosine; Anti-Bacterial Agents; Bacterial Proteins; Biosynthetic Pathways; Coformycin; GMP Reductase; Purine Nucleosides
PubMed: 30217843
DOI: 10.1128/AEM.01860-18 -
Journal of Bacteriology Feb 2012Helicobacter pylori is a chronic colonizer of the gastric epithelium and plays a major role in the development of gastritis, peptic ulcer disease, and gastric cancer. In...
Helicobacter pylori is a chronic colonizer of the gastric epithelium and plays a major role in the development of gastritis, peptic ulcer disease, and gastric cancer. In its coevolution with humans, the streamlining of the H. pylori genome has resulted in a significant reduction in metabolic pathways, one being purine nucleotide biosynthesis. Bioinformatic analysis has revealed that H. pylori lacks the enzymatic machinery for de novo production of IMP, the first purine nucleotide formed during GTP and ATP biosynthesis. This suggests that H. pylori must rely heavily on salvage of purines from the environment. In this study, we deleted several genes putatively involved in purine salvage and processing. The growth and survival of these mutants were analyzed in both nutrient-rich and minimal media, and the results confirmed the presence of a robust purine salvage pathway in H. pylori. Of the two phosphoribosyltransferase genes found in the H. pylori genome, only gpt appears to be essential, and an Δapt mutant strain was still capable of growth on adenine, suggesting that adenine processing via Apt is not essential. Deletion of the putative nucleoside phosphorylase gene deoD resulted in an inability of H. pylori to grow on purine nucleosides or the purine base adenine. Our results suggest a purine requirement for growth of H. pylori in standard media, indicating that H. pylori possesses the ability to utilize purines and nucleosides from the environment in the absence of a de novo purine nucleotide biosynthesis pathway.
Topics: Adenine Phosphoribosyltransferase; Helicobacter pylori; Hypoxanthine Phosphoribosyltransferase; Pentosyltransferases; Purine Nucleosides; Purine Nucleotides; Purines
PubMed: 22194455
DOI: 10.1128/JB.05757-11 -
The Journal of Biological Chemistry Jan 2001The human concentrative (Na(+)-linked) plasma membrane transport proteins hCNT1 and hCNT2 are selective for pyrimidine nucleosides (system cit) and purine nucleosides...
Molecular identification and characterization of novel human and mouse concentrative Na+-nucleoside cotransporter proteins (hCNT3 and mCNT3) broadly selective for purine and pyrimidine nucleosides (system cib).
The human concentrative (Na(+)-linked) plasma membrane transport proteins hCNT1 and hCNT2 are selective for pyrimidine nucleosides (system cit) and purine nucleosides (system cif), respectively. Both have homologs in other mammalian species and belong to a gene family (CNT) that also includes hfCNT, a newly identified broad specificity pyrimidine and purine Na(+)-nucleoside symporter (system cib) from the ancient marine vertebrate, the Pacific hagfish (Eptatretus stouti). We now report the cDNA cloning and characterization of cib homologs of hfCNT from human mammary gland, differentiated human myeloid HL-60 cells, and mouse liver. The 691- and 703-residue human and mouse proteins, designated hCNT3 and mCNT3, respectively, were 79% identical in amino acid sequence and contained 13 putative transmembrane helices. hCNT3 was 48, 47, and 57% identical to hCNT1, hCNT2, and hfCNT, respectively. When produced in Xenopus oocytes, both proteins exhibited Na(+)-dependent cib-type functional activities. hCNT3 was electrogenic, and a sigmoidal dependence of uridine influx on Na(+) concentration indicated a Na(+):uridine coupling ratio of at least 2:1 for both hCNT3 and mCNT3 (cf 1:1 for hCNT1/2). Phorbol myristate acetate-induced differentiation of HL-60 cells led to the parallel appearance of cib-type activity and hCNT3 mRNA. Tissues containing hCNT3 transcripts included pancreas, bone marrow, trachea, mammary gland, liver, prostate, and regions of intestine, brain, and heart. The hCNT3 gene mapped to chromosome 9q22.2 and included an upstream phorbol myristate acetate response element.
Topics: Amino Acid Sequence; Animals; Biological Transport; Carrier Proteins; Cell Differentiation; Dilazep; Dipyridamole; Electric Conductivity; Evolution, Molecular; HL-60 Cells; Humans; Membrane Transport Proteins; Mice; Models, Molecular; Molecular Sequence Data; Purine Nucleosides; Pyrimidine Nucleosides; Recombinant Proteins; Sequence Homology, Amino Acid; Sodium; Substrate Specificity; Symporters; Thioinosine; Uridine
PubMed: 11032837
DOI: 10.1074/jbc.M007746200 -
Journal of Infection and Public Health 2016The adenosine nucleoside analog BCX4430 is a direct-acting antiviral drug under investigation for the treatment of serious and life-threatening infections from highly... (Review)
Review
The adenosine nucleoside analog BCX4430 is a direct-acting antiviral drug under investigation for the treatment of serious and life-threatening infections from highly pathogenic viruses, such as the Ebola virus. Cellular kinases phosphorylate BCX4430 to a triphosphate that mimics ATP; viral RNA polymerases incorporate the drug's monophosphate nucleotide into the growing RNA chain, causing premature chain termination. BCX4430 is active in vitro against many RNA viral pathogens, including the filoviruses and emerging infectious agents such as MERS-CoV and SARS-CoV. In vivo, BCX4430 is active after intramuscular, intraperitoneal, and oral administration in a variety of experimental infections. In nonclinical studies involving lethal infections with Ebola virus, Marburg virus, Rift Valley fever virus, and Yellow Fever virus, BCX4430 has demonstrated pronounced efficacy. In experiments conducted in several models, both a reduction in the viral load and an improvement in survival were found to be related to the dose of BCX4430. A Phase 1 clinical trial of intramuscular administration of BCX4430 in healthy subjects is currently ongoing.
Topics: Adenine; Adenosine; Administration, Oral; Animals; Antiviral Agents; Clinical Trials, Phase I as Topic; Disease Models, Animal; Drug Discovery; Humans; Injections, Intramuscular; Injections, Intraperitoneal; Purine Nucleosides; Pyrrolidines; RNA Virus Infections; RNA Viruses; Treatment Outcome; Virus Replication
PubMed: 27095300
DOI: 10.1016/j.jiph.2016.04.002 -
ELife Mar 2024Cyclic nucleotide binding domains (CNB) confer allosteric regulation by cAMP or cGMP to many signaling proteins, including PKA and PKG. PKA of phylogenetically distant...
Cyclic nucleotide binding domains (CNB) confer allosteric regulation by cAMP or cGMP to many signaling proteins, including PKA and PKG. PKA of phylogenetically distant is the first exception as it is cyclic nucleotide-independent and responsive to nucleoside analogues (Bachmaier et al., 2019). Here, we show that natural nucleosides inosine, guanosine and adenosine are nanomolar affinity CNB ligands and activators of PKA orthologs of the important tropical pathogens , and . The sequence and structural determinants of binding affinity, -specificity and kinase activation of PKAR were established by structure-activity relationship (SAR) analysis, co-crystal structures and mutagenesis. Substitution of two to three amino acids in the binding sites is sufficient for conversion of CNB domains from nucleoside to cyclic nucleotide specificity. In addition, a trypanosomatid-specific C-terminal helix (αD) is required for high affinity binding to CNB-B. The αD helix functions as a lid of the binding site that shields ligands from solvent. Selectivity of guanosine for CNB-B and of adenosine for CNB-A results in synergistic kinase activation at low nanomolar concentration. PKA pulldown from rapid lysis establishes guanosine as the predominant ligand in vivo in bloodstream forms, whereas guanosine and adenosine seem to synergize in the procyclic developmental stage in the insect vector. We discuss the versatile use of CNB domains in evolution and recruitment of PKA for novel nucleoside-mediated signaling.
Topics: Purine Nucleosides; Cyclic AMP; Nucleosides; Allosteric Regulation; Nucleotides, Cyclic; Guanosine; Adenosine
PubMed: 38517938
DOI: 10.7554/eLife.91040 -
Dissecting interactions between nucleosides and germination receptors in Bacillus cereus 569 spores.Microbiology (Reading, England) Apr 2010Bacillus cereus 569 spores germinate either with inosine as a sole germinant or with a combination of nucleosides and L-alanine. Whereas the inosine-only germination...
Bacillus cereus 569 spores germinate either with inosine as a sole germinant or with a combination of nucleosides and L-alanine. Whereas the inosine-only germination pathway requires the presence of two different germination receptors (GerI and GerQ) to be activated, the nucleoside/alanine germination pathway only needs one of the two receptors. To differentiate how nucleoside recognition varies between the inosine-only germination pathway and the nucleoside/alanine germination pathway, we tested 61 purine analogues as agonists and antagonists of the two pathways in wild-type, DeltagerI and DeltagerQ spores. The structure-activity relationships of germination agonists and antagonists suggest that the inosine-only germination pathway is restricted to recognize a single germinant (inosine), but can be inhibited in predictable patterns by structurally distinct purine nucleosides. B. cereus spores encoding GerI as the only nucleoside receptor (DeltagerQ mutant) showed a germination inhibition profile similar to wild-type spores treated with inosine only. Thus, GerI seems to have a well-organized binding site that recognizes inosine and inhibitors through specific substrate-protein interactions. Structure-activity analysis also showed that the nucleoside/alanine germination pathway is more promiscuous toward purine nucleoside agonists, and is only inhibited by hydrophobic analogues. B. cereus spores encoding GerQ as the only nucleoside receptor (DeltagerI mutant) behaved like wild-type spores treated with inosine and L-alanine. Thus, the GerQ receptor seems to recognize substrates in a more flexible binding site through non-specific interactions. We propose that the GerI receptor is responsible for germinant detection in the inosine-only germination pathway. On the other hand, supplementing inosine with l-alanine allows bypassing of the GerI receptor to activate the more flexible GerQ receptor.
Topics: Alanine; Bacillus cereus; Bacterial Proteins; Gene Expression Regulation, Bacterial; Inosine; Nucleosides; Protein Binding; Spores, Bacterial
PubMed: 20035009
DOI: 10.1099/mic.0.030270-0 -
The Biochemical Journal Oct 2004Research on metabolism of nucleotides and their derivatives has gained increasing interest in the recent past. This includes de novo synthesis, analysis of salvage...
Research on metabolism of nucleotides and their derivatives has gained increasing interest in the recent past. This includes de novo synthesis, analysis of salvage pathways, breakdown and transport of nucleotides, nucleosides and nucleobases. To perform a further step towards the analysis of nucleoside transport in Arabidopsis, we incubated leaf discs with various radioactively labelled nucleosides. Leaf cells imported labelled nucleosides and incorporated these compounds into RNA, but not into DNA. Furthermore, we report on the biochemical properties of three so far uncharacterized members of the Arabidopsis ENT (equilibrative nucleoside transporter) family (AtENT4, AtENT6 and AtENT7). After heterologous expression in yeast, all three proteins exhibited broad substrate specificity and transported the purine nucleosides adenosine and guanosine, as well as the pyrimidine nucleosides cytidine and uridine. The apparent K(m) values were in the range 3-94 microM, and transport was inhibited most strongly by deoxynucleosides, and to a smaller extent by nucleobases. Typical inhibitors of mammalian ENT proteins, such as dilazep and NBMPR (nitrobenzylmercaptopurine ribonucleoside, also known as nitrobenzylthioinosine) surprisingly exerted almost no effect on Arabidopsis ENT proteins. Transport mediated by the AtENT isoforms differed in pH-dependency, e.g. AtENT7 was not affected by changes in pH, AtENT3, 4 and 6 exhibited a less pronounced pH-dependency, and AtENT1 activity was clearly pH-dependent. Using a GFP (green fluorescent protein)-fusion protein transiently expressed in tobacco leaf protoplasts, a localization of AtENT6 in the plant plasma membrane has been revealed.
Topics: Arabidopsis; Arabidopsis Proteins; Biological Transport; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Equilibrative Nucleoside Transport Proteins; Ionophores; Kinetics; Plant Leaves; Purine Nucleosides; Pyrimidine Nucleosides; Recombinant Fusion Proteins; Subcellular Fractions; Substrate Specificity; Vasodilator Agents
PubMed: 15228386
DOI: 10.1042/BJ20040389 -
Wiley Interdisciplinary Reviews.... 2013Folate-mediated one-carbon metabolism (FOCM) is associated with risk for numerous pathological states including birth defects, cancers, and chronic diseases. Although... (Review)
Review
Folate-mediated one-carbon metabolism (FOCM) is associated with risk for numerous pathological states including birth defects, cancers, and chronic diseases. Although the enzymes that constitute the biological pathways have been well described and their interdependency through the shared use of folate cofactors appreciated, the biological mechanisms underlying disease etiologies remain elusive. The FOCM network is highly sensitive to nutritional status of several B-vitamins and numerous penetrant gene variants that alter network outputs, but current computational approaches do not fully capture the dynamics and stochastic noise of the system. Combining the stochastic approach with a rule-based representation will help model the intrinsic noise displayed by FOCM, address the limited flexibility of standard simulation methods for coarse-graining the FOCM-associated biochemical processes, and manage the combinatorial complexity emerging from reactions within FOCM that would otherwise be intractable.
Topics: Carbon; Cell Nucleus; Cytoplasm; Folic Acid; Homocysteine; Methionine; Mitochondria; Models, Biological; Purine Nucleosides; Thymidine Monophosphate
PubMed: 23408533
DOI: 10.1002/wsbm.1209