Affinage

ENPP1

Ectonucleotide pyrophosphatase/phosphodiesterase family member 1 · UniProt P22413

Length
925 aa
Mass
104.9 kDa
Annotated
2026-06-09
100 papers in source corpus 31 papers cited in narrative 31 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ENPP1 is an extracellular nucleotide-metabolizing ectoenzyme whose hydrolytic products govern soft-tissue mineralization and innate immune signaling (PMID:25344812, PMID:26624227). Its dominant physiological function is catalytic generation of inorganic pyrophosphate (PPi) from extracellular substrates: loss-of-function mutation produces ectopic ligament ossification in the ttw mouse (PMID:9662402), and ENPP1 acts coordinately with TNAP at matrix vesicles to set extracellular PPi and osteopontin levels (PMID:15039209), such that enzyme-replacement with soluble ENPP1-Fc restores plasma PPi and prevents vascular calcification in Enpp1-null models (PMID:26624227). Independently, ENPP1 is the principal extracellular hydrolase of the STING agonist 2'3'-cGAMP, an activity that depends on the conserved active-site histidine H362; a selective H362A mutation abolishes cGAMP cleavage without affecting the PPi-generating function, separating immune regulation from mineralization control (PMID:25344812, PMID:35588451). Through cGAMP degradation ENPP1 dampens cGAS-STING-mediated antitumoral immunity, and selective loss of cGAMP hydrolysis phenocopies full knockout in a STING-dependent manner in breast tumor models (PMID:38117852). ENPP1 additionally exerts catalysis-independent protein-signaling functions: it promotes osteoblast differentiation and regulates bone mass by suppressing the soluble Wnt inhibitor Sfrp1 to sustain β-catenin signaling, a function retained by catalytically dead protein and separable by the T238A knock-in (PMID:21930712, PMID:35773783). Beyond bone and immunity, ENPP1 inhibits insulin receptor autophosphorylation and downstream signaling in an enzyme-activity-dependent fashion (PMID:19374858), suppresses vascular smooth muscle proliferation via AMP generation (PMID:30369595), and acts upstream of FGF-23 expression and phosphate homeostasis (PMID:22359666). Crystal structures of the human enzyme in apo, nucleotide-bound, and inhibitor-bound states have enabled structure-based inhibitor design (PMID:32876064, PMID:32726585).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 1998 High

    Established ENPP1 as a genetic determinant of soft-tissue mineralization, answering whether a single ectoenzyme controls ectopic calcification.

    Evidence Positional candidate-gene cloning of a Gly568Stop nonsense mutation in the ttw mouse model of spinal ligament ossification

    PMID:9662402

    Open questions at the time
    • Did not biochemically define the substrate generating the calcification-inhibiting product
    • C-terminal truncation mechanism not resolved at protein level
  2. 2004 High

    Defined where and with which partner ENPP1 sets extracellular PPi, showing it acts at matrix vesicles coordinately with TNAP.

    Evidence Akp2−/−;Enpp1−/− double-knockout epistasis, PPi and osteopontin quantification, matrix vesicle fractionation

    PMID:15039209

    Open questions at the time
    • Did not separate catalytic from non-catalytic contributions to the phenotype
    • Relationship to systemic phosphate handling not addressed
  3. 2012 High

    Connected ENPP1 to systemic phosphate homeostasis by demonstrating it regulates FGF-23 expression, broadening its role beyond local mineralization.

    Evidence Comprehensive Enpp1−/− phenotyping (micro-CT, biomechanics, plasma biochemistry, qPCR, ELISA)

    PMID:22359666

    Open questions at the time
    • Mechanism linking ENPP1 activity to Fgf-23 transcription not defined
    • Catalytic vs protein-signaling basis of FGF-23 regulation unresolved
  4. 2014 High

    Identified ENPP1 as the dominant extracellular hydrolase of the STING agonist 2'3'-cGAMP, revealing a second, immune-relevant enzymatic function.

    Evidence Activity-guided purification, recombinant in vitro hydrolysis, Enpp1−/− tissue/plasma depletion

    PMID:25344812

    Open questions at the time
    • Did not separate cGAMP hydrolysis from PPi-generating activity genetically
    • In vivo immune consequence not yet established
  5. 2015 High

    Demonstrated the protective function against vascular calcification is the catalytic generation of PPi, validating enzyme replacement as therapy.

    Evidence Subcutaneous recombinant ENPP1-Fc in Enpp1−/− mice with PPi, micro-CT, and histopathology readouts

    PMID:26624227

    Open questions at the time
    • Did not address contributions of cGAMP or AMP products
    • Long-term durability and dosing not fully characterized
  6. 2011 High

    Revealed a catalysis-independent role of ENPP1 in osteoblast differentiation, distinguishing protein-signaling from enzymatic functions.

    Evidence shRNA knockdown, catalytically inactive ENPP1 overexpression, Enpp1−/− primary calvarial cells, differentiation assays

    PMID:21930712

    Open questions at the time
    • Molecular partner mediating catalysis-independent signaling not identified in this study
  7. 2022 High

    Resolved which enzymatic activity drives the vascular phenotype by selectively ablating cGAMP hydrolysis, assigning antiviral immunity to the H362-dependent activity.

    Evidence Structure-guided H362A knock-in mice, viral infection models, comparison to bacterial NPP

    PMID:35588451

    Open questions at the time
    • Did not map all downstream immune effectors of restored STING signaling in vivo
  8. 2022 High

    Mapped the catalysis-independent bone function to suppression of Sfrp1 and restoration of Wnt/β-catenin signaling, separating it from PPi-dependent mineralization.

    Evidence Enpp1T238A knock-in mice, micro-CT, biomechanics, Sfrp1 knockout rescue in calvarial cultures, nuclear β-catenin measurement

    PMID:35773783

    Open questions at the time
    • Direct molecular mechanism by which ENPP1 protein suppresses Sfrp1 not defined
    • Receptor or binding partner for ENPP1 protein-signaling unknown
  9. 2023 High

    Established that ENPP1's cGAMP hydrolysis is the dominant mechanism by which it suppresses antitumoral immunity, providing a therapeutic rationale.

    Evidence Single-cell RNA-seq, cGAMP-hydrolysis-selective mutant phenocopying full KO in a STING-dependent manner in vivo

    PMID:38117852

    Open questions at the time
    • Relative contribution of AMP/adenosine products versus cGAMP loss in tumor immunity not fully partitioned
  10. 2009 High

    Showed ENPP1 inhibition of insulin receptor signaling requires its enzymatic activity, contrasting with its catalysis-independent bone role.

    Evidence Catalytically inactive T256A/T256S mutants vs wild-type in HEK293 cells with surface-expression controls and IR autophosphorylation assays

    PMID:19374858

    Open questions at the time
    • Substrate or product responsible for IR inhibition not defined
    • Direct physical interaction with insulin receptor not demonstrated
  11. 2018 High

    Defined the metabolite responsible for ENPP1's anti-proliferative vascular effect as AMP/adenosine rather than PPi.

    Evidence siRNA silencing in human VSMCs with rescue by ENPP1-Fc/AMP/adenosine vs PPi, plus carotid ligation model in ttw/ttw mice

    PMID:30369595

    Open questions at the time
    • Adenosine receptor mediating the anti-proliferative signal not identified in this study
  12. 2020 High

    Provided high-resolution human ENPP1 structures and validated phosphonate inhibitors, enabling structure-based drug design against cGAMP hydrolysis.

    Evidence X-ray crystallography of apo, nucleotide- and inhibitor-bound human ENPP1; SAR campaign with sub-2 nM inhibitors and in vivo tumor model

    PMID:32726585 PMID:32876064

    Open questions at the time
    • Structural basis for catalysis-independent protein signaling not addressed

Open questions

Synthesis pass · forward-looking unresolved questions
  • The molecular basis of ENPP1's catalysis-independent protein-signaling functions — including the binding partner/receptor mediating Sfrp1 and Wnt suppression and the physiological relevance of its protein-ADP-ribose processing activity — remains undefined.
  • No direct protein partner for catalysis-independent signaling identified
  • Physiological relevance of in vitro pR-generating activity unvalidated
  • Mechanism linking ENPP1 to FGF-23 and Klotho transcription unresolved

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016787 hydrolase activity 4 GO:0140098 catalytic activity, acting on RNA 4 GO:0098772 molecular function regulator activity 2 GO:0140096 catalytic activity, acting on a protein 1
Localization
GO:0005886 plasma membrane 2 GO:0031410 cytoplasmic vesicle 2
Pathway
R-HSA-1430728 Metabolism 4 R-HSA-168256 Immune System 4 R-HSA-1266738 Developmental Biology 3 R-HSA-162582 Signal Transduction 3
Partners
GALNT2HSP70INSULIN RECEPTORSFRP1TNAP
Complex memberships
ENPP1 homodimer

Evidence

Reading pass · 31 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2014 ENPP1 is the dominant 2'3'-cGAMP hydrolyzing activity in cultured cells. Recombinant ENPP1 protein was confirmed to hydrolyze 2'3'-cGAMP; this activity was depleted in tissue extracts and plasma from Enpp1−/− mice. ENPP1 thus acts as an extracellular phosphodiesterase that degrades the endogenous STING agonist 2'3'-cGAMP. Activity-guided partial purification, recombinant protein in vitro hydrolysis assay, Enpp1−/− mouse tissue/plasma depletion experiments Nature chemical biology High 25344812
1998 A nonsense mutation (Gly568Stop) in the Npps gene (encoding nucleotide pyrophosphatase/ENPP1) causes the ttw mouse phenotype of spinal ligament ossification. ENPP1 generates inorganic pyrophosphate (PPi), a major inhibitor of calcification; loss of the C-terminal third of the protein leads to ectopic ossification. Positional candidate-gene approach, mutation identification by sequencing in ttw mouse model Nature genetics High 9662402
2004 ENPP1/NPP1 generates extracellular inorganic pyrophosphate (PPi) and localizes to matrix vesicles, where it regulates PPi levels. Double-knockout epistasis experiments (Akp2−/−;Enpp1−/−) demonstrated that NPP1 and TNAP coordinately regulate extracellular PPi and osteopontin levels; NPP1 but not ANK localizes to the matrix vesicle compartment, explaining the greater severity of Enpp1−/− versus ank/ank hypermineralization. Mouse genetic epistasis (double-knockout crosses), PPi measurements, OPN mRNA/serum quantification, matrix vesicle fractionation/localization The American journal of pathology High 15039209
2015 ENPP1-Fc fusion protein (soluble ENPP1) enzymatically restores plasma PPi levels when administered subcutaneously, preventing mortality, vascular calcifications, and sequelae in a rodent GACI model. This demonstrates that ENPP1's primary protective function against vascular calcification is catalytic generation of extracellular PPi. Subcutaneous administration of recombinant ENPP1-Fc in Enpp1−/− mice; plasma PPi measurement; micro-CT, histopathology for calcification Nature communications High 26624227
2022 A point mutation (H362A) in ENPP1 selectively abolishes hydrolysis of the 2′-5′ linkage in cGAMP while maintaining otherwise normal enzymatic function. Enpp1H362A mice demonstrated that extracellular cGAMP hydrolysis is not responsible for the vascular calcification phenotype of ENPP1-null animals, but is responsible for antiviral immunity and systemic inflammation regulation. The histidine at position 362 is evolutionarily conserved down to bacterial NPP, establishing an ancient cGAMP-hydrolyzing function. Structure-guided mutagenesis, Enpp1H362A knock-in mice, viral infection models, structural comparison to bacterial NPP Proceedings of the National Academy of Sciences of the United States of America High 35588451
2020 Crystal structures of human ENPP1 were solved in apo form, with bound nucleotides, and with two known inhibitors. These are the first X-ray crystal structures of the human (rather than mouse) enzyme, enabling structure-based drug design. X-ray crystallography Acta crystallographica. Section D, Structural biology High 32876064
2020 Structure-activity relationships around phosphonate inhibitors of ENPP1 were defined, and a crystal structure of an exemplary phosphonate inhibitor bound to ENPP1 was solved, elucidating active-site interactions. Best-in-class inhibitors with Ki < 2 nM were developed that delay tumor growth in a breast cancer mouse model by blocking extracellular cGAMP hydrolysis. SAR campaign, X-ray crystal structure of inhibitor-ENPP1 complex, in vivo mouse tumor model Cell chemical biology High 32726585
2016 ENPP1 processes protein ADP-ribosylation in vitro by converting protein-conjugated ADP-ribose (mono- and poly-ADP-ribose) to protein-conjugated ribose-5′-phosphate (pR), acting through a mechanism distinct from NUDIX-domain enzymes. This identifies ENPP1 as the first mammalian non-NUDIX enzyme capable of generating pR from ADP-ribosylated proteins. In vitro enzymatic assay with purified recombinant ENPP1, mass spectrometry identification of pR product The FEBS journal Medium 27406238
2012 Enpp1−/− mice show severely disrupted long-bone architecture, hypomineralization of skeleton alongside ectopic soft-tissue calcification, reduced plasma calcium and phosphate, and a 12-fold increase in Fgf-23 mRNA in calvarial osteoblasts with elevated circulating FGF-23. This establishes ENPP1 as a regulator of FGF-23 expression and phosphate homeostasis. Phenotypic characterization of Enpp1−/− mice (micro-CT, 3-point bending, plasma biochemistry, qPCR, ELISA) PloS one High 22359666
2011 ENPP1 regulates osteoblast differentiation through a mechanism independent of its catalytic activity and independent of changes in extracellular phosphate or pyrophosphate. shRNA knockdown of ENPP1 in preosteoblasts and calvarial cells from Enpp1−/− mice impaired differentiation; overexpression of catalytically inactive ENPP1 still enhanced differentiation and osteoblast marker gene expression. shRNA knockdown, catalytic-dead ENPP1 overexpression, Enpp1−/− primary calvarial cells, osteoblast differentiation assays The Journal of biological chemistry High 21930712
2009 Inhibition of insulin receptor signaling by PC-1/ENPP1 is dependent on its enzymatic (phosphodiesterase/pyrophosphatase) activity. Catalytically inactive T256A and T256S mutants of ENPP1 (retaining <10% of wild-type activity) failed to inhibit insulin-induced receptor autophosphorylation in HEK293 cells stably expressing the insulin receptor, whereas wild-type ENPP1 did. Both wild-type and mutant proteins were expressed at similar levels on the cell surface. In vitro enzymatic assay of purified extracellular domain mutants, transient expression in HEK293 cells, insulin-stimulated IR autophosphorylation assay, Western blot, FACS European journal of pharmacology High 19374858
2022 Catalysis-independent ENPP1 signaling regulates mammalian bone mass via suppression of Wnt signaling. Enpp1T238A knock-in mice (catalytically impaired) have normal trabecular bone microarchitecture unlike Enpp1asj mice (ENPP1-null), despite equivalent plasma PPi and phosphate wasting. The mechanism involves ENPP1 protein-dependent suppression of Sfrp1 (a soluble Wnt inhibitor); knockout of Sfrp1 in Enpp1asj calvarial cultures restored normal β-catenin signaling and calcification. Enpp1T238A knock-in mice, micro-CT, biomechanical testing, calvarial cell culture, Sfrp1 knockout rescue experiment, nuclear β-catenin measurement Journal of bone and mineral research High 35773783
2018 ENPP1 inhibits neointima formation by generating AMP from ATP hydrolysis. Silencing ENPP1 in human vascular smooth muscle cells caused a 10-fold increase in proliferation; addition of recombinant ENPP1-Fc, AMP, or adenosine reversed this effect. PPi and etidronate had no effect on VSMC proliferation. rhENPP1-Fc prevented and treated intimal hyperplasia in a carotid ligation model in Enpp1-deficient ttw/ttw mice. siRNA silencing of ENPP1 in human VSMCs, rescue with rhENPP1-Fc/AMP/adenosine/PPi, in vivo carotid ligation mouse model Experimental & molecular medicine High 30369595
2023 ENPP1 drives primary breast tumor growth and metastasis by dampening extracellular 2'3'-cGAMP-STING-mediated antitumoral immunity. Selective abolishment of cGAMP hydrolysis activity (without full ENPP1 knockout) 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. Single-cell RNA-seq, ENPP1 loss-of-function in cancer cells and normal tissues, cGAMP-hydrolysis-selective mutant, STING dependency experiments in vivo Proceedings of the National Academy of Sciences of the United States of America High 38117852
2018 Hedgehog (Hh) signaling contributes to ectopic joint calcification in Enpp1-deficient mice. In Enpp1−/− joints, Hh signaling was upregulated. Further activation of Hh (by Ptch1 deletion) enhanced calcification; removing Gli2 partially rescued it. ENPP1 was found to inhibit Hh signaling and chondrocyte hypertrophy by activating Gαs-PKA signaling. Enpp1−/− mouse model, genetic epistasis (Ptch1 deletion, Gli2 deletion, Gαs reduction) in Enpp1-deficient background, histology and micro-CT Development (Cambridge, England) Medium 30111653
2018 ENPP1 in plasma cells is required for survival of long-lived plasma cells (LLPCs) in bone marrow. Enpp1−/− mice produced significantly reduced LLPCs following immunization; bone marrow chimera experiments showed a B-cell-intrinsic effect. ENPP1-deficient plasma cells had lower glycolytic activity and glucose uptake, suggesting ENPP1's ATP-degrading activity supports an energetic advantage for LLPC maintenance. Enpp1−/− mice, immunization, bone marrow chimeric mice, flow cytometry for plasma cell subsets, metabolic (glycolysis, glucose uptake) assays Scientific reports Medium 29259245
2017 ENPP1 loss-of-function mutations in the somatomedin-B-like 2 (SMB2) domain impair homodimerization of the ENPP1 enzyme. Biallelic cysteine-specific mutations in the SMB2 domain cause recessive Cole disease with melanocyte-specific effects, as ENPP1 is not expressed in keratinocytes. RNA-seq of patient melanocytes revealed alterations in melanocyte development and pigmentation signaling pathways. Homozygosity mapping, whole-exome sequencing, homodimerization assay (mutation functional assessment), patient-derived primary melanocyte RNA-seq The Journal of investigative dermatology Medium 28964717
2020 ENPP1 deficiency suppresses Wnt ligand transcription in bone and increases soluble Wnt inhibitors (including Sfrp1) in liver and kidney, creating multiorgan inhibition of Wnt/β-catenin activity. At 10 weeks, the skeletal phenotype correlates with Enpp1 transcript levels but not plasma PPi, indicating catalysis-independent ENPP1 function; at 23 weeks, the phenotype correlates with plasma PPi, indicating catalysis-dependent pathways dominate in older mice. ENPP1-Fc dosing suppressed intact plasma FGF23 and ALP. RNAseq and qPCR in whole bone, liver, kidney of Enpp1asj/asj mice; correlation analysis with micro-CT/biomechanical phenotypes; ENPP1-Fc dosing experiment Bone Medium 32980560
2013 GALNT2 (N-acetylgalactosaminyltransferase 2) binds to the ENPP1 3′-UTR and modulates ENPP1 expression: GALNT2 downregulation increased ENPP1 levels while overexpression reduced them. Changes in GALNT2 expression accordingly affected insulin receptor (IR), IRS-1, and Akt phosphorylation and PEPCK expression in human HepG2 liver cells, placing GALNT2 upstream of ENPP1 in insulin signaling regulation. RNA pull-down, mass spectrometry identification of 3′-UTR binding proteins, RT-PCR, Western blot, IR autophosphorylation ELISA Biochimica et biophysica acta Medium 23500900
2008 Heat shock protein 70 (HSP70) binds the ENPP1 3′-UTR, stabilizes ENPP1 mRNA, and increases ENPP1 transcript and protein levels. This increased ENPP1 expression is paralleled by reduced insulin-induced IR and IRS-1 phosphorylation, establishing HSP70 as a post-transcriptional regulator of ENPP1 expression. RNA electrophoresis mobility shift assay (REMSA), tandem mass spectrometry, RT-PCR, Western blot for IR/IRS-1 phosphorylation Journal of molecular medicine (Berlin, Germany) Medium 19083193
2017 Enpp1 is required for Klotho expression under phosphate-overload conditions. Enpp1 ttw/ttw mice on phosphate-overload exhibited reduced renal Klotho expression, elevated serum 1,25(OH)2D3, and aging-like phenotypes (short lifespan, arteriosclerosis, osteoporosis). These phenotypes were rescued by Klotho overexpression, low-vitamin-D diet, or vitamin D receptor knockout, placing ENPP1 upstream of Klotho and vitamin D signaling. Enpp1 ttw/ttw mouse model on phosphate-overload diet, Klotho overexpression rescue, vitamin D receptor KO genetic epistasis, qPCR for renal Klotho, serum biochemistry Scientific reports Medium 28798354
2018 Osterix (Osx/SP7) transcriptionally activates ENPP1 in osteoblasts and osteocytes. Osx overexpression in MC3T3-E1 and MLO-Y4 cells upregulated ENPP1; consensus Sp1 sequences in the proximal ENPP1 promoter were identified as Osx-binding sites by promoter truncation experiments and ChIP assays. The p38-MAPK pathway mediates this activation, and Runx2 has synergistic effects with Osx on the ENPP1 promoter. Overexpression studies, promoter truncation assays, chromatin immunoprecipitation (ChIP), p38-MAPK inhibitor experiments European cells & materials Medium 30047979
2010 RAGE (receptor for advanced glycation end-products) mediates arterial calcification in Enpp1-deficient mice. S100A11 (a RAGE ligand/calgranulin) induced cartilage-specific collagen IX/XI expression and calcification in mouse aortic explants via RAGE; this was inhibited by soluble RAGE (sRAGE). Enpp1−/− aortic explants showed decreased Pi-stimulated sRAGE release and increased calcification suppressible by exogenous sRAGE or Rage knockout in situ. Mouse aortic explant culture with S100A11/RAGE manipulation, sRAGE addition experiments, Rage/Enpp1 double-knockout mice, immunohistochemistry for collagen IX/XI Journal of vascular research Medium 21099228
2022 ENPP1-generated adenosinergic metabolites (downstream of cGAMP hydrolysis and ATP hydrolysis) enhance haptoglobin (HP) expression in tumor cells, which in turn elicits myeloid invasiveness and promotes neutrophil extracellular trap (NET) formation. Genetic and pharmacologic ENPP1 inhibition blocked this ENPP1/HP axis and extended relapse-free survival; combination with fractionated irradiation obliterated local recurrence. Genetic ENPP1 inhibition, pharmacologic ENPP1 inhibition, NET blockade, in vivo breast cancer relapse models, mechanistic cell signaling assays Cancer discovery Medium 35191482
2012 ENPP1 (PC-1) is a negative regulator of BMP-2 signaling in human mesenchymal stem cells (hMSCs): knockdown of ENPP1 increased BMP2 mRNA and protein expression. ENPP1 expression was restricted to cells in direct contact with osteoinductive calcium phosphate ceramic surfaces, dependent on local ionic (chemical) depletion rather than surface structure alone. ENPP1 knockdown in hMSCs (siRNA), BMP2 ELISA and RT-PCR, comparison of osteoinductive vs. non-osteoinductive CaP ceramics, polystyrene surface replica control Biomaterials Medium 31048198
2024 Tumor-derived exosomes carry surface ENPP1 that retains cGAMP hydrolytic activity. Tumor exosomal ENPP1 hydrolyzes both synthetic 2'3'-cGAMP and endogenous cGAMP produced by cells, inhibits cGAS-STING pathway activation in immune cells, and can hydrolyze cGAMP bound to the transporter LL-37. This demonstrates an extravesicular mode of STING pathway suppression. Isolation of tumor-derived exosomes, in vitro cGAMP hydrolysis assay, cGAS-STING pathway readouts in immune cells, LL-37/cGAMP hydrolysis assay Advanced science Medium 38498770
2014 ENPP1 is required for maintenance of glioblastoma stem-like cells (GSCs) in vitro. Knockdown of ENPP1 in cultured GSCs decreased CD133, induced astrocytic differentiation, impaired sphere formation, increased cell death, caused G1/G0 cell cycle accumulation, and decreased E2F1 transcriptional activity. Genome-wide expression and nucleotide profiling linked ENPP1 to purine/pyrimidine metabolism balance in GSCs. Phosphatome-wide RNAi screen, ENPP1 shRNA knockdown, sphere formation assay, flow cytometry, genome-wide gene expression analysis, nucleotide profiling Cell death and differentiation Medium 24531536
2011 ENPP1 overexpression in liver and skeletal muscle cells (HepG2, L6) reduces insulin-induced IR autophosphorylation and downstream Akt, ERK1/2, and GSK3-β phosphorylation, decreases glucose uptake, and reduces GLUT4 mRNA. In beta cells (INS1E), ENPP1 overexpression reduced glucose-induced insulin secretion. The Q121 variant produced stronger inhibition than K121 in all cell types. ENPP1 cDNA transfection (K121 and Q121 variants) in HepG2, L6, INS1E cells; IR autophosphorylation ELISA; Akt/ERK/GSK3-β Western blot; 2-deoxyglucose uptake; insulin secretion assay; isolated human islets from QQ vs KK donors PloS one Medium 21573217
2018 ENPP1 maintains cGAMP homeostasis in porcine cells during pseudorabies virus (PRV) infection. Porcine ENPP1 hydrolyzed cGAMP in PRV-infected or cGAMP-transfected cells and inhibited IRF3 phosphorylation, reducing IFN-β secretion. ENPP1 overexpression enhanced PRV infection while ENPP1 silencing attenuated it and promoted IFN-β and NF-κB activation. ENPP1 overexpression and siRNA silencing in porcine cells, cGAMP hydrolysis assay, IRF3 phosphorylation Western blot, IFN-β and NF-κB reporter assays, PRV infection quantification Molecular immunology Medium 29407577
2007 ENPP1 overexpression in 3T3-L1 preadipocytes caused adipocyte insulin resistance and defective adipocyte maturation. Conversely, adipocyte maturation was more efficient in mesenchymal cells from Enpp1−/− mice than wild-type. ENPP1 is downregulated during normal 3T3-L1 differentiation, placing it as a negative regulator of adipogenesis. ENPP1 overexpression in 3T3-L1 cells, Enpp1−/− mouse-derived mesenchymal cell differentiation, Oil Red O staining, insulin signaling assays PloS one Medium 17849011
2012 Expression and preliminary structural analysis of mouse Enpp1 extracellular domain: crystallized and diffracted to 2.7 Å resolution using SAD phasing with selenomethionine-labeled crystals. This laid the structural groundwork for subsequent higher-resolution structures. Protein expression in HEK293S GnT1− cells, crystallography (SAD phasing, 2.7 Å resolution) Acta crystallographica. Section F Medium 22750863

Source papers

Stage 0 corpus · 100 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2014 Hydrolysis of 2'3'-cGAMP by ENPP1 and design of nonhydrolyzable analogs. Nature chemical biology 439 25344812
2004 Concerted regulation of inorganic pyrophosphate and osteopontin by akp2, enpp1, and ank: an integrated model of the pathogenesis of mineralization disorders. The American journal of pathology 401 15039209
1998 Mutation in Npps in a mouse model of ossification of the posterior longitudinal ligament of the spine. Nature genetics 343 9662402
2011 Generalized arterial calcification of infancy and pseudoxanthoma elasticum can be caused by mutations in either ENPP1 or ABCC6. American journal of human genetics 273 22209248
2005 Variants of ENPP1 are associated with childhood and adult obesity and increase the risk of glucose intolerance and type 2 diabetes. Nature genetics 244 16025115
2010 Autosomal-recessive hypophosphatemic rickets is associated with an inactivation mutation in the ENPP1 gene. American journal of human genetics 209 20137772
1999 Association of the human NPPS gene with ossification of the posterior longitudinal ligament of the spine (OPLL). Human genetics 154 10453738
2015 Loss of microRNA-27b contributes to breast cancer stem cell generation by activating ENPP1. Nature communications 136 26065921
2015 ENPP1-Fc prevents mortality and vascular calcifications in rodent model of generalized arterial calcification of infancy. Nature communications 121 26624227
2012 Altered bone development and an increase in FGF-23 expression in Enpp1(-/-) mice. PloS one 117 22359666
2019 ENPP1, an Old Enzyme with New Functions, and Small Molecule Inhibitors-A STING in the Tale of ENPP1. Molecules (Basel, Switzerland) 103 31752288
2020 Structure-Aided Development of Small-Molecule Inhibitors of ENPP1, the Extracellular Phosphodiesterase of the Immunotransmitter cGAMP. Cell chemical biology 97 32726585
2022 ENPP1's regulation of extracellular cGAMP is a ubiquitous mechanism of attenuating STING signaling. Proceedings of the National Academy of Sciences of the United States of America 94 35588451
2006 Studies of the relationship between the ENPP1 K121Q polymorphism and type 2 diabetes, insulin resistance and obesity in 7,333 Danish white subjects. Diabetologia 92 16865358
2016 ENPP1 processes protein ADP-ribosylation in vitro. The FEBS journal 72 27406238
2011 A patient with hypophosphatemic rickets and ossification of posterior longitudinal ligament caused by a novel homozygous mutation in ENPP1 gene. Bone 69 21745613
2005 Overexpression of the insulin receptor inhibitor PC-1/ENPP1 induces insulin resistance and hyperglycemia. American journal of physiology. Endocrinology and metabolism 68 16278247
2014 Stem cell characteristics in glioblastoma are maintained by the ecto-nucleotidase E-NPP1. Cell death and differentiation 64 24531536
2009 Association and interaction analyses of genetic variants in ADIPOQ, ENPP1, GHSR, PPARgamma and TCF7L2 genes for diabetic nephropathy in a Taiwanese population with type 2 diabetes. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 63 19506043
2006 Common variants in the ENPP1 gene are not reproducibly associated with diabetes or obesity. Diabetes 63 17065359
2011 Ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1) protein regulates osteoblast differentiation. The Journal of biological chemistry 61 21930712
2013 Enpp1: a potential facilitator of breast cancer bone metastasis. PloS one 60 23861746
2022 Tumor ENPP1 (CD203a)/Haptoglobin Axis Exploits Myeloid-Derived Suppressor Cells to Promote Post-Radiotherapy Local Recurrence in Breast Cancer. Cancer discovery 58 35191482
2023 ENPP1 is an innate immune checkpoint of the anticancer cGAMP-STING pathway in breast cancer. Proceedings of the National Academy of Sciences of the United States of America 57 38117852
2023 ENPP1 Immunobiology as a Therapeutic Target. Clinical cancer research : an official journal of the American Association for Cancer Research 54 36719675
2019 Human Heterozygous ENPP1 Deficiency Is Associated With Early Onset Osteoporosis, a Phenotype Recapitulated in a Mouse Model of Enpp1 Deficiency. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 54 31805212
2018 ENPP1-Fc prevents neointima formation in generalized arterial calcification of infancy through the generation of AMP. Experimental & molecular medicine 54 30369595
2017 Hypercementosis Associated with ENPP1 Mutations and GACI. Journal of dental research 49 29244957
2010 The expression of ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (E-NPP1) is correlated with astrocytic tumor grade. Clinical neurology and neurosurgery 46 21195542
2013 Cole Disease Results from Mutations in ENPP1. American journal of human genetics 44 24075184
2006 No evidence for association of the ENPP1 (PC-1) K121Q variant with risk of type 2 diabetes in a Japanese population. Journal of human genetics 44 16607460
2006 ENPP1 variants and haplotypes predispose to early onset obesity and impaired glucose and insulin metabolism in German obese children. The Journal of clinical endocrinology and metabolism 44 16968801
2024 Tumor Exosomal ENPP1 Hydrolyzes cGAMP to Inhibit cGAS-STING Signaling. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 43 38498770
2007 Role of ENPP1 on adipocyte maturation. PloS one 43 17849011
2011 Metabolic consequences of ENPP1 overexpression in adipose tissue. American journal of physiology. Endocrinology and metabolism 42 21810932
2020 Clinical and Biochemical Phenotypes in a Family With ENPP1 Mutations. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 41 31826312
2008 The association of ENPP1 K121Q with diabetes incidence is abolished by lifestyle modification in the diabetes prevention program. The Journal of clinical endocrinology and metabolism 40 19017751
2007 Ethnic differences in the frequency of ENPP1/PC1 121Q genetic variant in the Dallas Heart Study cohort. Journal of diabetes and its complications 40 17493546
2021 INZ-701 Prevents Ectopic Tissue Calcification and Restores Bone Architecture and Growth in ENPP1-Deficient Mice. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 39 33900645
2011 ENPP1 affects insulin action and secretion: evidences from in vitro studies. PloS one 39 21573217
2008 Haplotype structure of the ENPP1 Gene and Nominal Association of the K121Q missense single nucleotide polymorphism with glycemic traits in the Framingham Heart Study. Diabetes 39 18426862
2020 Crystal structures of human ENPP1 in apo and bound forms. Acta crystallographica. Section D, Structural biology 36 32876064
2009 New variants in the Enpp1 and Ptpn6 genes cause low BMD, crystal-related arthropathy, and vascular calcification. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 36 19419305
2007 ENPP1 K121Q polymorphism and obesity, hyperglycaemia and type 2 diabetes in the prospective DESIR Study. Diabetologia 36 17704904
2007 ENPP1 gene, insulin resistance and related clinical outcomes. Current opinion in clinical nutrition and metabolic care 35 17563456
2019 Dysregulated ENPP1 increases the malignancy of human lung cancer by inducing epithelial-mesenchymal transition phenotypes and stem cell features. American journal of cancer research 34 30755817
2018 ENPP1 enzyme replacement therapy improves blood pressure and cardiovascular function in a mouse model of generalized arterial calcification of infancy. Disease models & mechanisms 34 30158213
2010 Arterial calcification is driven by RAGE in Enpp1-/- mice. Journal of vascular research 33 21099228
2021 Response of the ENPP1-Deficient Skeletal Phenotype to Oral Phosphate Supplementation and/or Enzyme Replacement Therapy: Comparative Studies in Humans and Mice. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 32 33465815
2020 Genetic pathways disrupted by ENPP1 deficiency provide insight into mechanisms of osteoporosis, osteomalacia, and paradoxical mineralization. Bone 32 32980560
2023 ENPP1 in Blood and Bone: Skeletal and Soft Tissue Diseases Induced by ENPP1 Deficiency. Annual review of pathology 31 37871131
2018 Reduced Orthodontic Tooth Movement in Enpp1 Mutant Mice with Hypercementosis. Journal of dental research 30 29533727
2018 Maintenance of cyclic GMP-AMP homeostasis by ENPP1 is involved in pseudorabies virus infection. Molecular immunology 29 29407577
2017 ATP-degrading ENPP1 is required for survival (or persistence) of long-lived plasma cells. Scientific reports 28 29259245
2011 Effects of mechanical strain on ANK, ENPP1 and TGF-β1 expression in rat endplate chondrocytes in vitro. Molecular medicine reports 28 21674130
2009 Evidence that inhibition of insulin receptor signaling activity by PC-1/ENPP1 is dependent on its enzyme activity. European journal of pharmacology 28 19374858
2022 ENPP1 variants in patients with GACI and PXE expand the clinical and genetic heterogeneity of heritable disorders of ectopic calcification. PLoS genetics 27 35482848
2017 Enpp1 is an anti-aging factor that regulates Klotho under phosphate overload conditions. Scientific reports 27 28798354
2014 Spontaneous asj-2J mutant mouse as a model for generalized arterial calcification of infancy: a large deletion/insertion mutation in the Enpp1 gene. PloS one 27 25479107
2013 Role of GALNT2 in the modulation of ENPP1 expression, and insulin signaling and action: GALNT2: a novel modulator of insulin signaling. Biochimica et biophysica acta 27 23500900
2021 Design, synthesis and biological evaluation studies of novel small molecule ENPP1 inhibitors for cancer immunotherapy. Bioorganic chemistry 26 34929517
2019 The role of ENPP1/PC-1 in osteoinduction by calcium phosphate ceramics. Biomaterials 26 31048198
2017 ENPP1 Mutation Causes Recessive Cole Disease by Altering Melanogenesis. The Journal of investigative dermatology 26 28964717
2013 Hearing loss is part of the clinical picture of ENPP1 loss of function mutation. Hormone research in paediatrics 26 24216977
2024 T Cell-Derived Apoptotic Extracellular Vesicles Hydrolyze cGAMP to Alleviate Radiation Enteritis via Surface Enzyme ENPP1. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 25 38888507
2018 Enpp1 inhibits ectopic joint calcification and maintains articular chondrocytes by repressing hedgehog signaling. Development (Cambridge, England) 24 30111653
2009 ENPP1 Q121 variant, increased pulse pressure and reduced insulin signaling, and nitric oxide synthase activity in endothelial cells. Arteriosclerosis, thrombosis, and vascular biology 22 19679831
2024 Surface and Global Proteome Analyses Identify ENPP1 and Other Surface Proteins as Actionable Immunotherapeutic Targets in Ewing Sarcoma. Clinical cancer research : an official journal of the American Association for Cancer Research 21 37812652
2020 Improving the Pharmacodynamics and In Vivo Activity of ENPP1-Fc Through Protein and Glycosylation Engineering. Clinical and translational science 21 33064927
2012 Adipose tissue dysfunction in humans: a potential role for the transmembrane protein ENPP1. The Journal of clinical endocrinology and metabolism 21 23012391
2025 Oral ENPP1 inhibitor designed using generative AI as next generation STING modulator for solid tumors. Nature communications 20 40410143
2022 INZ-701, a recombinant ENPP1 enzyme, prevents ectopic calcification in an Abcc6-/- mouse model of pseudoxanthoma elasticum. Experimental dermatology 20 35511611
2011 ENPP1/PC-1 gene K121Q polymorphism is associated with obesity in European adult populations: evidence from a meta-analysis involving 24,324 subjects. Biomedical and environmental sciences : BES 20 21565692
2011 ENPP1 K121Q polymorphism and type 2 diabetes mellitus in the Chinese population: a meta-analysis including 11,855 subjects. Metabolism: clinical and experimental 20 22136912
2010 Impact of ENPP1 and MMP3 gene polymorphisms on aortic calcification in patients with type 2 diabetes in a Korean population. Diabetes research and clinical practice 20 20092902
2010 The ENPP1 K121Q polymorphism is not associated with type 2 diabetes or obesity in the Chinese Han population. Journal of human genetics 20 20981035
2008 Association of the ENPP1 K121Q polymorphism with type 2 diabetes and obesity in the Moroccan population. Diabetes & metabolism 20 19046915
2022 Catalysis-Independent ENPP1 Protein Signaling Regulates Mammalian Bone Mass. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 19 35773783
2021 Musculoskeletal Comorbidities and Quality of Life in ENPP1-Deficient Adults and the Response of Enthesopathy to Enzyme Replacement Therapy in Murine Models. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 19 34882836
2016 The ENPP1 K121Q polymorphism is associated with type 2 diabetes and related metabolic phenotypes in a Taiwanese population. Molecular and cellular endocrinology 19 27238374
2010 ENPP1/PC-1 K121Q polymorphism and genetic susceptibility to type 2 diabetes in North Indians. Molecular and cellular biochemistry 19 20820885
2022 Development of Novel Ecto-Nucleotide Pyrophosphatase/Phosphodiesterase 1 (ENPP1) Inhibitors for Tumor Immunotherapy. International journal of molecular sciences 18 35806118
2019 Novel homozygous ENPP1 mutation causes generalized arterial calcifications of infancy, thrombocytopenia, and cardiovascular and central nervous system syndrome. American journal of medical genetics. Part A 18 31444901
2016 ENPP1 and ESR1 genotypes influence temporomandibular disorders development and surgical treatment response in dentofacial deformities. Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery 18 27519661
2009 Association of ALPL and ENPP1 gene polymorphisms with bone strength related skeletal traits in a Chuvashian population. Bone 18 19931660
2023 Targeting ENPP1 for cancer immunotherapy: Killing two birds with one stone. Biochemical pharmacology 17 38142838
2022 AVA-NP-695 Selectively Inhibits ENPP1 to Activate STING Pathway and Abrogate Tumor Metastasis in 4T1 Breast Cancer Syngeneic Mouse Model. Molecules (Basel, Switzerland) 17 36235254
2015 Effects of etidronate on the Enpp1⁻/⁻ mouse model of generalized arterial calcification of infancy. International journal of molecular medicine 17 25975272
2008 Further evidence for the role of ENPP1 in obesity: association with morbid obesity in Finns. Obesity (Silver Spring, Md.) 16 18551113
2007 Association of ENPP1 (PC-1) K121Q polymorphism with obesity-related parameters in subjects with metabolic syndrome. Clinical endocrinology 16 17986276
2023 Human antibodies targeting ENPP1 as candidate therapeutics for cancers. Frontiers in immunology 15 36761762
2022 Estimation of ENPP1 deficiency genetic prevalence using a comprehensive literature review and population databases. Orphanet journal of rare diseases 15 36461014
2018 Transcriptional activation of ENPP1 by osterix in osteoblasts and osteocytes. European cells & materials 15 30047979
2012 Expression, purification, crystallization and preliminary X-ray crystallographic analysis of Enpp1. Acta crystallographica. Section F, Structural biology and crystallization communications 15 22750863
2008 The role of HSP70 on ENPP1 expression and insulin-receptor activation. Journal of molecular medicine (Berlin, Germany) 15 19083193
2015 Association between the ENPP1 K121Q polymorphism and risk of diabetic kidney disease: a systematic review and meta-analysis. PloS one 14 25794151
2022 Case Report and Review of Literature: Autosomal Recessive Hypophosphatemic Rickets Type 2 Caused by a Pathogenic Variant in ENPP1 Gene. Frontiers in endocrinology 13 35966073
2016 Plasma cell alloantigen ENPP1 is expressed by a subset of human B cells with potential regulatory functions. Immunology and cell biology 13 27029896
2009 Genetic variants of the ENPP1/PC-1 gene are associated with hypertriglyceridemia in male subjects. Metabolic syndrome and related disorders 13 19656007
2023 HER2Δ16 Engages ENPP1 to Promote an Immune-Cold Microenvironment in Breast Cancer. Cancer immunology research 12 37311021

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