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The Journal of Biological Chemistry Feb 2022Ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP) family members (ENPP1-7) have been implicated in key biological and pathophysiological processes, including... (Review)
Review
Ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP) family members (ENPP1-7) have been implicated in key biological and pathophysiological processes, including nucleotide and phospholipid signaling, bone mineralization, fibrotic diseases, and tumor-associated immune cell infiltration. ENPPs are single-pass transmembrane ecto-enzymes, with notable exceptions of ENPP2 (Autotaxin) and ENNP6, which are secreted and glycosylphosphatidylinositol (GPI)-anchored, respectively. ENNP1 and ENNP2 are the best characterized and functionally the most interesting members. Here, we review the structural features of ENPP1-7 to understand how they evolved to accommodate specific substrates and mediate different biological activities. ENPPs are defined by a conserved phosphodiesterase (PDE) domain. In ENPP1-3, the PDE domain is flanked by two N-terminal somatomedin B-like domains and a C-terminal inactive nuclease domain that confers structural stability, whereas ENPP4-7 only possess the PDE domain. Structural differences in the substrate-binding site endow each protein with unique characteristics. Thus, ENPP1, ENPP3, ENPP4, and ENPP5 hydrolyze nucleotides, whereas ENPP2, ENPP6, and ENNP7 evolved as phospholipases through adaptions in the catalytic domain. These adaptations explain the different biological and pathophysiological functions of individual members. Understanding the ENPP members as a whole advances our insights into common mechanisms, highlights their functional diversity, and helps to explore new biological roles.
Topics: Catalytic Domain; Nucleotides; Phosphoric Diester Hydrolases; Pyrophosphatases; Signal Transduction; Structure-Activity Relationship
PubMed: 34958798
DOI: 10.1016/j.jbc.2021.101526 -
Proceedings of the National Academy of... May 2022The metazoan innate immune second messenger 2′3′-cGAMP is present both inside and outside cells. However, only extracellular cGAMP can be negatively regulated by the...
The metazoan innate immune second messenger 2′3′-cGAMP is present both inside and outside cells. However, only extracellular cGAMP can be negatively regulated by the extracellular hydrolase ENPP1. Here, we determine whether ENPP1’s regulation of extracellular cGAMP is a ubiquitous mechanism of attenuating stimulator of interferon genes (STING) signaling. We identified ENPP1H362A, a point mutation that cannot degrade the 2′-5′ linkage in cGAMP while maintaining otherwise normal function. The selectivity of this histidine is conserved down to bacterial nucleotide pyrophosphatase/phosphodiesterase (NPP), allowing structural analysis and suggesting an unexplored ancient history of 2′-5′ cyclic dinucleotides. Enpp1H362A mice demonstrated that extracellular cGAMP is not responsible for the devastating phenotype in ENPP1-null humans and mice but is responsible for antiviral immunity and systemic inflammation. Our data define extracellular cGAMP as a pivotal STING activator, identify an evolutionarily critical role for ENPP1 in regulating inflammation, and suggest a therapeutic strategy for viral and inflammatory conditions by manipulating ENPP1 activity.
Topics: Animals; Humans; Immunity, Innate; Inflammation; Membrane Proteins; Mice; Nucleotides, Cyclic; Phosphoric Diester Hydrolases; Pyrophosphatases; Signal Transduction
PubMed: 35588451
DOI: 10.1073/pnas.2119189119 -
Proceedings of the National Academy of... Dec 2023Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) expression correlates with poor prognosis in many cancers, and we previously discovered that ENPP1 is the...
Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) expression correlates with poor prognosis in many cancers, and we previously discovered that ENPP1 is the dominant hydrolase of extracellular cGAMP: a cancer-cell-produced immunotransmitter that activates the anticancer stimulator of interferon genes (STING) pathway. However, ENPP1 has other catalytic activities and the molecular and cellular mechanisms contributing to its tumorigenic effects remain unclear. Here, using single-cell RNA-seq, we show that ENPP1 in both cancer and normal tissues drives primary breast tumor growth and metastasis by dampening extracellular 2'3'-cyclic-GMP-AMP (cGAMP)-STING-mediated antitumoral immunity. ENPP1 loss-of-function in both cancer cells and normal tissues slowed primary tumor growth and abolished metastasis. Selectively abolishing the cGAMP hydrolysis activity of ENPP1 phenocopied ENPP1 knockout in a STING-dependent manner, demonstrating that restoration of paracrine cGAMP-STING signaling is the dominant anti-cancer mechanism of ENPP1 inhibition. Finally, expression in breast tumors deterministically predicated whether patients would remain free of distant metastasis after pembrolizumab (anti-PD-1) treatment followed by surgery. Altogether, ENPP1 blockade represents a strategy to exploit cancer-produced extracellular cGAMP for controlled local activation of STING and is therefore a promising therapeutic approach against breast cancer.
Topics: Female; Humans; Breast Neoplasms; Immunity, Innate; Membrane Proteins; Phosphoric Diester Hydrolases; Pyrophosphatases
PubMed: 38117852
DOI: 10.1073/pnas.2313693120 -
Nature Genetics Oct 2016Maize production is threatened by drought stress worldwide. Identification of the genetic components underlying drought tolerance in maize is of great importance. Here...
Maize production is threatened by drought stress worldwide. Identification of the genetic components underlying drought tolerance in maize is of great importance. Here we report a genome-wide association study (GWAS) of maize drought tolerance at the seedling stage that identified 83 genetic variants, which were resolved to 42 candidate genes. The peak GWAS signal showed that the natural variation in ZmVPP1, encoding a vacuolar-type H(+) pyrophosphatase, contributes most significantly to the trait. Further analysis showed that a 366-bp insertion in the promoter, containing three MYB cis elements, confers drought-inducible expression of ZmVPP1 in drought-tolerant genotypes. Transgenic maize with enhanced ZmVPP1 expression exhibits improved drought tolerance that is most likely due to enhanced photosynthetic efficiency and root development. Taken together, this information provides important genetic insights into the natural variation of maize drought tolerance. The identified loci or genes can serve as direct targets for both genetic engineering and selection for maize trait improvement.
Topics: Adaptation, Biological; Droughts; Genes, Plant; Genetic Variation; Genome-Wide Association Study; Plants, Genetically Modified; Pyrophosphatases; Seedlings; Stress, Physiological; Zea mays
PubMed: 27526320
DOI: 10.1038/ng.3636 -
Bone May 2020Extracellular pyrophosphate (ePP) was first identified as a key endogenous inhibitor of mineralisation in the 1960's by Fleisch and colleagues. The main source of ePP... (Review)
Review
Extracellular pyrophosphate (ePP) was first identified as a key endogenous inhibitor of mineralisation in the 1960's by Fleisch and colleagues. The main source of ePP seems to be extracellular ATP which is continually released from cells in a controlled way. ATP is rapidly broken down by enzymes including ecto-nucleotide pyrophosphatase/phosphodiesterases to produce ePP. The major function of ePP is to directly inhibit hydroxyapatite formation and growth meaning that this simple molecule acts as the body's own "water softener". However, studies have also shown that ePP can influence gene expression and regulate its own production and breakdown. This review will summarise our current knowledge of ePP metabolism and how it acts to prevent pathological soft tissue calcification and regulate physiological bone mineralisation.
Topics: Calcification, Physiologic; Calcinosis; Diphosphates; Humans; Phosphoric Diester Hydrolases; Pyrophosphatases; Water
PubMed: 31954851
DOI: 10.1016/j.bone.2020.115243 -
Cellular and Molecular Life Sciences :... Apr 2021Extracellular NAD represents a key signaling molecule in different physiological and pathological conditions. It exerts such function both directly, through the... (Review)
Review
Extracellular NAD represents a key signaling molecule in different physiological and pathological conditions. It exerts such function both directly, through the activation of specific purinergic receptors, or indirectly, serving as substrate of ectoenzymes, such as CD73, nucleotide pyrophosphatase/phosphodiesterase 1, CD38 and its paralog CD157, and ecto ADP ribosyltransferases. By hydrolyzing NAD, these enzymes dictate extracellular NAD availability, thus regulating its direct signaling role. In addition, they can generate from NAD smaller signaling molecules, like the immunomodulator adenosine, or they can use NAD to ADP-ribosylate various extracellular proteins and membrane receptors, with significant impact on the control of immunity, inflammatory response, tumorigenesis, and other diseases. Besides, they release from NAD several pyridine metabolites that can be taken up by the cell for the intracellular regeneration of NAD itself. The extracellular environment also hosts nicotinamide phosphoribosyltransferase and nicotinic acid phosphoribosyltransferase, which inside the cell catalyze key reactions in NAD salvaging pathways. The extracellular forms of these enzymes behave as cytokines, with pro-inflammatory functions. This review summarizes the current knowledge on the extracellular NAD metabolome and describes the major biochemical properties of the enzymes involved in extracellular NAD metabolism, focusing on the contribution of their catalytic activities to the biological function. By uncovering the controversies and gaps in their characterization, further research directions are suggested, also to better exploit the great potential of these enzymes as therapeutic targets in various human diseases.
Topics: ADP Ribose Transferases; Animals; Disease; Humans; Metabolome; NAD; Pentosyltransferases; Pyrophosphatases; Signal Transduction
PubMed: 33755743
DOI: 10.1007/s00018-020-03742-1 -
Biomolecules Jan 2022Most free-living organisms encode for a deoxyuridine triphosphate nucleotidohydrolase (dUTPase; EC 3.6.1.23). dUTPases represent a family of metalloenzymes that catalyze... (Review)
Review
Most free-living organisms encode for a deoxyuridine triphosphate nucleotidohydrolase (dUTPase; EC 3.6.1.23). dUTPases represent a family of metalloenzymes that catalyze the hydrolysis of dUTP to dUMP and pyrophosphate, preventing dUTP from being incorporated into DNA by DNA polymerases, maintaining a low dUTP/dTTP pool ratio and providing a necessary precursor for dTTP biosynthesis. Thus, dUTPases are involved in maintaining genomic integrity by preventing the uracilation of DNA. Many DNA-containing viruses, which infect mammals also encode for a dUTPase. This review will summarize studies demonstrating that, in addition to their classical enzymatic activity, some dUTPases possess novel functions that modulate the host innate immune response.
Topics: Animals; DNA; Immunity, Innate; Mammals; Pyrophosphatases
PubMed: 35204728
DOI: 10.3390/biom12020227 -
Microbiology (Reading, England) Dec 2020Nudix proteins catalyse hydrolysis of pyrophosphate bonds in a variety of substrates and are ubiquitous in all domains of life. Their widespread presence and broad... (Review)
Review
Nudix proteins catalyse hydrolysis of pyrophosphate bonds in a variety of substrates and are ubiquitous in all domains of life. Their widespread presence and broad substrate specificity suggest that they have important cellular functions. In this review, we summarize the state of knowledge on microbial Nudix proteins involved in pathogenesis.
Topics: Amino Acid Sequence; Bacterial Proteins; Diphosphates; Pyrophosphatases; Sequence Alignment; Viral Proteins; Virulence; Virulence Factors; Nudix Hydrolases
PubMed: 33253082
DOI: 10.1099/mic.0.000993 -
Current Opinion in Pharmacology Jun 2016Inorganic pyrophosphate has long been known as a by-product of many intracellular biosynthetic reactions, and was first identified as a key endogenous inhibitor of... (Review)
Review
Inorganic pyrophosphate has long been known as a by-product of many intracellular biosynthetic reactions, and was first identified as a key endogenous inhibitor of biomineralisation in the 1960s. The major source of pyrophosphate appears to be extracellular ATP, which is released from cells in a controlled manner. Once released, ATP can be rapidly hydrolysed by ecto-nucleotide pyrophosphatase/phosphodiesterases to produce pyrophosphate. The main action of pyrophosphate is to directly inhibit hydroxyapatite formation thereby acting as a physiological 'water-softener'. Evidence suggests pyrophosphate may also act as a signalling molecule to influence gene expression and regulate its own production and breakdown. This review will summarise our current understanding of pyrophosphate metabolism and how it regulates bone mineralisation and prevents harmful soft tissue calcification.
Topics: Adenosine Triphosphate; Animals; Calcification, Physiologic; Calcinosis; Diphosphates; Gene Expression Regulation; Humans; Phosphoric Diester Hydrolases; Pyrophosphatases; Signal Transduction
PubMed: 27061894
DOI: 10.1016/j.coph.2016.03.003 -
European Journal of Medicinal Chemistry Mar 2024The cancer immunotherapies involved in cGAS-STING pathway have been made great progress in recent years. STING agonists exhibit broad-spectrum anti-tumor effects with... (Review)
Review
The cancer immunotherapies involved in cGAS-STING pathway have been made great progress in recent years. STING agonists exhibit broad-spectrum anti-tumor effects with strong immune response. As a negative regulator of the cGAS-STING pathway, ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) can hydrolyze extracellular 2', 3'-cGAMP and reduce extracellular 2', 3'-cGAMP concentration. ENPP1 has been validated to play important roles in diabetes, cancers, and cardiovascular disease and now become a promising target for tumor immunotherapy. Several ENPP1 inhibitors under development have shown good anti-tumor effects alone or in combination with other agents in clinical and preclinical researches. In this review, the biological profiles of ENPP1 were described, and the structures and the structure-activity relationships (SAR) of the known ENPP1 inhibitors were summarized. This review also provided the prospects and challenges in the development of ENPP1 inhibitors.
Topics: Humans; Phosphoric Diester Hydrolases; Neoplasms; Nucleotidyltransferases; Immunotherapy; Pyrophosphatases
PubMed: 38359537
DOI: 10.1016/j.ejmech.2024.116211