{"gene":"ART1","run_date":"2026-06-09T22:02:44","timeline":{"discoveries":[{"year":2003,"finding":"ART2 (ARTC1 family)-catalyzed ADP-ribosylation of P2X7 purinoceptor on T cell surfaces activates the receptor, causing calcium flux, pore formation, phosphatidylserine exposure, shedding of CD62L, cell shrinkage, and propidium iodide uptake, establishing NAD-induced T cell death (NICD) via the ART2-P2X7 axis.","method":"Cell-based assays (flow cytometry, propidium iodide uptake, calcium flux), pharmacological inhibition, and ART2-deficient T cells","journal":"Immunity","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal functional readouts, ART2-deficient controls, replicated by subsequent independent studies","pmids":["14563321"],"is_preprint":false},{"year":2002,"finding":"Crystal structure of rat ART2.2 (ortholog of ART1 family) determined at 1.7 Å resolution; the active center was identified by a bound nicotinamide analogue revealing induced-fit upon substrate binding, and the NAD+ binding mode was modeled. Two disulfide bridges distant from the active center stabilize the protein. The fold places ART2.2 in a distinct subfamily of ADP-ribosyltransferases.","method":"X-ray crystallography (1.7 Å), ligand soaking with nicotinamide analogue, structural modeling of NAD+ binding","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with active-site ligand and functional modeling, peer-reviewed","pmids":["12270706"],"is_preprint":false},{"year":2002,"finding":"ART2.1/ART2.2 double-knockout T cells exhibit dramatically reduced ADP-ribosylation of cell surface proteins and are completely resistant to NAD-induced apoptosis and partially resistant to NAD-mediated suppression of proliferation, demonstrating that the ART2 ectoenzymes are essential for NAD-mediated T cell regulation.","method":"Genetic knockout mice, flow cytometry-based ADP-ribosylation assay, T cell proliferation and apoptosis assays","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean double-KO with multiple orthogonal readouts, peer-reviewed","pmids":["12370300"],"is_preprint":false},{"year":1998,"finding":"Mouse Art1 encodes a GPI-anchored ecto-enzyme predominantly expressed in cardiac and skeletal muscle. Recombinant Art1 expressed as an IgG1-Fc fusion exhibits arginine-specific ADP-ribosyltransferase activity in vitro.","method":"Northern blot, RT-PCR, recombinant expression in 293T cells, enzymatic activity assay","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct enzymatic activity assay in single lab with molecular characterization","pmids":["9841866"],"is_preprint":false},{"year":2005,"finding":"ART2.2 activity and substrate specificity depend on its GPI anchor-mediated association with lipid rafts: GPI-anchored ART2.2 showed >10-fold higher activity at limiting NAD concentrations and ADP-ribosylated a restricted set of target proteins compared to transmembrane-anchored ART2.2. Disruption of lipid rafts broadened substrate specificity. Auto-ADP-ribosylation of ART2.2 itself required GPI anchoring and raft association.","method":"Lymphoma transfectants expressing GPI- vs. transmembrane-anchored ART2.2, enzymatic activity assays, cholesterol depletion (cyclodextrin), detergent solubilization","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (transfectants, lipid raft disruption, activity assays), mechanistic comparison of two ART2.2 variants","pmids":["15657180"],"is_preprint":false},{"year":2000,"finding":"ART2.2 is shed from the T cell surface in enzymatically active form upon T cell activation via metalloprotease-mediated cleavage close to its membrane anchor (similar to TNF-alpha converting enzyme/ADAM17 cleavage of CD62L). Shed ART2.2 ADP-ribosylates substrates in vitro, and shedding correlates with reduced ADP-ribosylation capacity of the T cell surface.","method":"FACS-based ADP-ribosylation assay, metalloprotease inhibitor (Immunex Compound 3), SDS-PAGE, in vitro ADP-ribosylation assay","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological inhibitor + functional assay in single lab","pmids":["11035085"],"is_preprint":false},{"year":2007,"finding":"NAD+ released during acute inflammation in vivo induces ART2- and P2X7-dependent depletion of naive T cells in draining lymph nodes, preferentially targeting naive over recently activated/memory T cells. This effect was absent in ART2-deficient mice, demonstrating ART2's essential role in inflammation-induced T cell homeostasis in vivo.","method":"In vivo inflammation model (polyacrylamide beads), intravenous NAD+ injection, ART2-KO and CD38-KO mice, flow cytometry, antibody response assay","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO controls, in vivo model, multiple functional readouts across independent mouse strains","pmids":["17579037"],"is_preprint":false},{"year":2010,"finding":"Regulatory T cells (Treg) express high levels of ART2.2 and P2X7; ART2.2-mediated ADP-ribosylation of P2X7 by extracellular NAD+ depletes Tregs in vivo. Selective depletion of Tregs by systemic NAD+ administration promotes antitumor responses in mouse tumor models. An inhibitory ART2.2-specific single-domain antibody protects Tregs from NAD+-induced effects.","method":"Intravenous NAD+ injection in mice, flow cytometry, ART2-KO and P2X7-KO mice, single-domain antibody blocking, tumor models","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple KO strains, in vivo tumor models, antibody blockade, replicated across multiple tumor models","pmids":["20975043"],"is_preprint":false},{"year":2007,"finding":"Single-domain antibodies (VHH) from llama immunized against ART2.2 specifically block ART2.2 enzymatic and cytotoxic activities in vivo within 15 min of intravenous injection, with blockade reversible within 24 h. The blocking was specific for ART2.2 and did not affect the related enzymes ART1 or ART2.1.","method":"Llama immunization, VHH generation, intravenous injection in mice, flow cytometry-based ADP-ribosylation and cell death assays","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo functional blockade with specificity controls, single lab","pmids":["17575259"],"is_preprint":false},{"year":2006,"finding":"ART2 (rat T cell surface isoform) catalyzes formation of extracellular poly(ADP-ribose) rather than solely mono-ADP-ribosylation; auto-ADP-ribosylation at Arg-185 produces ADP-ribose polymer identified by PR-AMP detection via HPLC and MS/MS. Intestinal intraepithelial lymphocyte ART2 undergoes multimeric auto-ADP-ribosylation more efficiently than peripheral T cell ART2, correlating with greater resistance to NAD-induced cell death.","method":"Purified recombinant ART2, sequencing gel, HPLC, MS/MS mass spectrometry, site-directed identification of Arg-185","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with multiple analytical methods (HPLC, MS/MS, sequencing gel) in single lab","pmids":["16931513"],"is_preprint":false},{"year":2007,"finding":"LPS, IFN-gamma, and IFN-beta selectively induce expression of ART2.1 (but not ART2.2) as a GPI-anchored cell surface ectoenzyme in bone marrow-derived macrophages. The catalytic function of induced ART2.1 requires extracellular thiol-reducing cofactors (allosteric disulfide bond regulation). Induction is blocked by inhibitors of NF-κB, PI3K, and JAK-STAT pathways but potentiated by ERK1/2 inhibition.","method":"BMDM isolation, LPS/IFN stimulation, flow cytometry, pharmacological pathway inhibitors, ADP-ribosylation activity assay with thiol reductants","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct enzymatic activity measurements with pathway inhibitors, single lab","pmids":["17947697"],"is_preprint":false},{"year":2008,"finding":"ART1 gene expression in skeletal muscle is driven by cooperative binding of myogenin to an E-box and MEF-2 to an A/T-rich element in the proximal promoter (~1.3 kb upstream of TSS). Mutation of either element nearly abolishes promoter inducibility. Gel mobility shift assays confirmed binding of myogenin and MEF-2 restricted to myotubes.","method":"Promoter deletion analysis, luciferase reporter assay in C2C12 and C3H-10T1/2 cells, site-directed mutagenesis of E-box and A/T-rich element, gel mobility shift assay (EMSA) with nuclear extracts","journal":"BMC molecular biology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — mutagenesis + EMSA + reporter assay, single lab","pmids":["18939989"],"is_preprint":false},{"year":2014,"finding":"Human ARTC1 localizes to the endoplasmic reticulum (ER) — unlike other GPI-anchored ARTC family members — and ADP-ribosylates the ER luminal chaperone GRP78/BiP. ARTC1 is activated during ER stress, resulting in acute ADP-ribosylation of GRP78/BiP coinciding with translational inhibition.","method":"Immunofluorescence co-localization, macro-domain pull-down to identify ADP-ribosylated proteins, overexpression of ARTC1, ER stress induction, co-localization with GRP78/BiP","journal":"Cellular and molecular life sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — macro-domain binding module + immunofluorescence + ER stress induction, single lab","pmids":["25292337"],"is_preprint":false},{"year":2018,"finding":"ARTC1 ADP-ribosylates hundreds of arginine-containing proteins on the cell surface and in the extracellular space of skeletal muscle and heart tissue, as determined by mass spectrometry comparing wild-type and ARTC1-deficient mice. Hemopexin (HPX) was validated as an ARTC1 substrate. Target proteins are associated with signal transduction, transmembrane transport, and muscle function.","method":"Mass spectrometry-based ADP-ribosylome profiling of C2C12 myotubes and tissues from WT vs. ARTC1-KO mice, site-specific identification of arginine ADP-ribosylation","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1 / Strong — proteome-wide MS with KO controls, multiple orthogonal validations, substrate site identification","pmids":["30110646"],"is_preprint":false},{"year":2005,"finding":"ARTC1 peptide ligands derived from mutated tumor cell proteins are presented by MHC class II and specifically recognized by tumor-infiltrating CD4+ regulatory T cell clones, which then suppress proliferation and IL-2 secretion of melanoma-reactive T cells. Tumor cells (but not tumor lysate-pulsed B cells) directly activate these Treg clones.","method":"Establishment of CD4+ Treg clones from TILs, antigen identification by expression cloning, T cell suppression assay (proliferation, IL-2 secretion), tumor cell co-culture","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional T cell clones, antigen identification, suppression assay, single lab","pmids":["15728473"],"is_preprint":false},{"year":2022,"finding":"ART1 expressed on tumor cell membranes mediates ADP-ribosylation and NICD of P2X7R+ CD8 T cells, reducing their infiltration into non-small cell lung cancer. Genetic or antibody-mediated ART1 inhibition in murine NSCLC and melanoma models slowed tumor growth in a CD8 T cell-dependent manner and increased P2X7R+CD8 T cell tumor infiltration.","method":"In vitro NICD assay with P2X7R+CD8 T cells, genetic ART1 KO in tumor cell lines, antibody-mediated ART1 blockade in syngeneic mouse tumor models, CD8 T cell depletion experiments, flow cytometry","journal":"Science translational medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO + antibody blockade + CD8 depletion, multiple tumor models, mechanistic in vitro confirmation","pmids":["35294260"],"is_preprint":false},{"year":2013,"finding":"ART1 silencing in mouse CT26 colon carcinoma cells enhances cisplatin-induced apoptosis, correlating with reduced phospho-Akt(Thr308), reduced phospho-IκBα, reduced NF-κB p65 nuclear translocation, decreased Bcl-2 and Bcl-xL expression, and increased Bax expression.","method":"Lentiviral shRNA knockdown of ART1, flow cytometry (apoptosis), Western blot (Akt, IκBα, NF-κB, Bcl-2 family proteins)","journal":"Cellular physiology and biochemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — KD with defined pathway readouts, single lab, multiple markers measured","pmids":["24335275"],"is_preprint":false},{"year":2015,"finding":"ART1 knockdown or overexpression in CT26 colon carcinoma cells modulates Akt and Erk signaling pathway activity and expression of βIII-tubulin (Tubb3), which acts downstream of both Akt and Erk to influence apoptosis. Inhibiting either Akt or Erk downregulates Tubb3 at protein and mRNA levels, placing Tubb3 as a convergent downstream effector.","method":"Lentiviral KD and OE of ART1, in vivo allograft transplant model, Western blot, pathway inhibitors (Akt and Erk inhibitors), mRNA analysis","journal":"Tumour biology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, KD/OE with pathway inhibitors but no direct ART1-substrate identification","pmids":["26373733"],"is_preprint":false},{"year":2015,"finding":"ART1 overexpression promotes starvation-induced autophagy in CT26 colon carcinoma cells via a pathway involving increased Rac1, NF-κB, PARP-1, LKB1, and p-AMPK and decreased p-P70S6K. ART1 co-immunoprecipitates with integrin α7 in these cells.","method":"Lentiviral OE and KD, electron microscopy and LC3B Western blot (autophagy), Co-IP (ART1–integrin α7), pharmacological inhibitors (Rac1, PARP-1)","journal":"American journal of cancer research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, Co-IP without reciprocal validation, pathway inhibitors without direct mechanistic mapping to ART1 enzymatic function","pmids":["25973293"],"is_preprint":false},{"year":2024,"finding":"ARTC1 ADP-ribosylates VAPB at Arg50, and knockdown of hARTC1 impairs intracellular calcium homeostasis. hARTC3 interacts with hARTC1 and stabilizes it, promoting its enzymatic activity.","method":"Co-IP (hARTC3–hARTC1 interaction), ADP-ribosylation site mapping (Arg50 of VAPB), hARTC1 knockdown, calcium homeostasis assay","journal":"Journal of molecular cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — site-specific ADP-ribosylation mapping, Co-IP, functional calcium assay, single lab","pmids":["37381178"],"is_preprint":false},{"year":2023,"finding":"In ARTC1-KO and Artc1/Arh1 double-KO mice, spontaneous tumorigenesis is decreased and multi-organ inflammation with TNF-α upregulation is increased. In xenograft models, tumorigenicity of Arh1-KO MEFs was decreased in Artc1-KO hosts, with increased CD8+ T cell and macrophage tumor infiltration and necroptosis. Artc1-KO male mice exhibit reduced myocardial contractility and enhanced susceptibility to ischemia-reperfusion injury with increased RIP3 protein levels, suggesting ARTC1 suppresses necroptosis in heart.","method":"Artc1-KO and Artc1/Arh1-double-KO mice, spontaneous tumor monitoring, xenograft model, echocardiography/MRI, ischemia-reperfusion model, Western blot (RIP3, TNF-α), flow cytometry (immune infiltrates)","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple KO models, orthogonal readouts, but preprint not yet peer-reviewed","pmids":["36945646"],"is_preprint":true},{"year":2006,"finding":"ART2.1 substrate specificity is altered by the protein's membrane vs. solution environment: detergent solubilization or GPI-anchor cleavage by PI-PLC changes the spectrum of histone proteins ADP-ribosylated. Soluble ART2.1 in serum ADP-ribosylates albumin and transferrin, identified by mass spectrometry.","method":"Phospholipase C treatment, detergent solubilization, in vitro ADP-ribosylation with [32P]-NAD, SDS-PAGE, mass spectrometry identification of substrates","journal":"Journal of cellular biochemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro enzymatic assay with MS substrate identification, single lab","pmids":["16453289"],"is_preprint":false}],"current_model":"ART1/ARTC1 is a GPI-anchored, arginine-specific ecto-ADP-ribosyltransferase expressed predominantly in skeletal and cardiac muscle (and, upon induction, in immune cells) that transfers ADP-ribose from extracellular NAD+ to arginine residues on cell surface and extracellular target proteins — including P2X7 purinoceptor (activating it to induce T cell death), integrin α7, hemopexin, and VAPB — with enzyme activity and substrate specificity modulated by GPI-anchor-dependent lipid raft association, thiol-redox status (ART2.1 isoform), metalloprotease-mediated ectodomain shedding, and interaction with hARTC3; in muscle tissue ARTC1 mediates widespread arginine ADP-ribosylation of extracellular proteins and suppresses necroptosis, while on immune cells its NAD-dependent ADP-ribosylation of P2X7 controls T cell and regulatory T cell homeostasis and constitutes a tumor immune-evasion mechanism."},"narrative":{"mechanistic_narrative":"ART1/ARTC1 is a GPI-anchored, arginine-specific ecto-ADP-ribosyltransferase, predominantly expressed in cardiac and skeletal muscle, that transfers ADP-ribose from extracellular NAD+ onto arginine residues of cell-surface and extracellular target proteins [PMID:9841866, PMID:30110646]. In muscle tissue it carries out widespread arginine ADP-ribosylation of hundreds of extracellular and surface proteins, including the validated substrate hemopexin, modifying targets linked to signal transduction, transmembrane transport, and muscle function [PMID:30110646]. Muscle-restricted ARTC1 expression is driven by cooperative binding of myogenin to an E-box and MEF-2 to an A/T-rich element in the proximal promoter [PMID:18939989]. The closely related ARTC1-family ectoenzyme ART2 ADP-ribosylates the P2X7 purinoceptor on T cells, activating it to trigger calcium flux, pore formation, phosphatidylserine exposure, and NAD-induced cell death (NICD), a pathway abolished in ART2-deficient T cells [PMID:14563321, PMID:12370300]; in vivo this axis depletes naive T cells during inflammation and depletes P2X7-high regulatory T cells, with Treg depletion promoting antitumor responses [PMID:17579037, PMID:20975043]. On tumor cells, ART1 itself ADP-ribosylates P2X7R+ CD8 T cells to drive their NICD and exclude them from tumors, constituting an immune-evasion mechanism whose genetic or antibody blockade slows tumor growth in a CD8-dependent manner [PMID:35294260]. Enzyme activity and substrate specificity are controlled by GPI-anchor-dependent lipid-raft association, which restricts substrate range and supports auto-ADP-ribosylation, and by metalloprotease-mediated ectodomain shedding of active enzyme from the cell surface [PMID:15657180, PMID:11035085]. A subset of human ARTC1 localizes atypically to the endoplasmic reticulum where it ADP-ribosylates the chaperone GRP78/BiP during ER stress [PMID:25292337], and it modifies VAPB at Arg50 to influence calcium homeostasis, with hARTC3 binding and stabilizing ARTC1 to promote its activity [PMID:37381178].","teleology":[{"year":1998,"claim":"Established the molecular identity of the gene product: that mouse Art1 is a GPI-anchored ecto-enzyme with intrinsic arginine-specific ADP-ribosyltransferase activity expressed in muscle.","evidence":"Northern/RT-PCR expression profiling and recombinant IgG1-Fc fusion enzymatic activity assay in 293T cells","pmids":["9841866"],"confidence":"Medium","gaps":["In vitro substrates not physiological","No structure or active-site mapping","Muscle function of the enzyme not addressed"]},{"year":2002,"claim":"Resolved the catalytic architecture and demonstrated, genetically, that family ectoenzymes are required for NAD-mediated T cell regulation.","evidence":"1.7 Å crystal structure of rat ART2.2 with nicotinamide-analogue ligand, plus ART2.1/2.2 double-KO T cell apoptosis and proliferation assays","pmids":["12270706","12370300"],"confidence":"High","gaps":["Structure is of ART2.2 ortholog, not ART1 itself","Surface substrate driving T cell death not yet identified at this step"]},{"year":2003,"claim":"Identified the effector substrate of NAD-induced T cell death, defining the ART2–P2X7 axis as the mechanism converting extracellular NAD+ into a death signal.","evidence":"Flow cytometry, calcium flux, PI uptake, pharmacological inhibition, and ART2-deficient T cells","pmids":["14563321"],"confidence":"High","gaps":["ADP-ribosylated arginine site on P2X7 not mapped here","Did not address ART1 enzyme specifically"]},{"year":2005,"claim":"Defined how GPI-anchor-dependent lipid raft localization tunes enzyme activity and narrows substrate specificity.","evidence":"GPI- vs transmembrane-anchored ART2.2 transfectants with cholesterol depletion and activity assays","pmids":["15657180"],"confidence":"High","gaps":["Raft composition mediating specificity not defined","Generalization to ART1 in muscle not shown"]},{"year":2000,"claim":"Showed enzyme abundance at the cell surface is dynamically regulated by metalloprotease-mediated shedding, decoupling enzyme location from activity.","evidence":"FACS ADP-ribosylation assay with metalloprotease inhibitor and in vitro activity of shed enzyme","pmids":["11035085"],"confidence":"Medium","gaps":["Specific protease not genetically confirmed","Physiological consequence of shed soluble enzyme unclear"]},{"year":2006,"claim":"Revealed catalytic versatility — poly(ADP-ribose) formation and auto-modification at Arg-185 — and linked auto-modification to cell-death resistance, while showing membrane environment reshapes substrate choice.","evidence":"Purified recombinant ART2 with HPLC, MS/MS, PI-PLC and detergent solubilization assays","pmids":["16931513","16453289"],"confidence":"High","gaps":["Findings on ART2/ART2.1 orthologs, not human ART1","Physiological relevance of extracellular poly(ADP-ribose) unresolved"]},{"year":2007,"claim":"Demonstrated in vivo that the NAD+/ART2/P2X7 axis controls T cell homeostasis during inflammation and that the enzyme is inducible and redox-regulated in myeloid cells, while establishing blocking antibodies as tools.","evidence":"In vivo inflammation and NAD+ injection in ART2-KO/CD38-KO mice, BMDM induction assays, and VHH single-domain antibody blockade","pmids":["17579037","17947697","17575259"],"confidence":"High","gaps":["ART2.1 thiol-redox regulation mechanism at the structural level not resolved","Distinction between ART1 and ART2 roles in vivo not parsed"]},{"year":2008,"claim":"Explained the muscle-restricted expression of ART1 through a defined myogenic transcriptional program.","evidence":"Promoter deletion/mutagenesis, luciferase reporters in myoblasts/myotubes, and EMSA for myogenin and MEF-2","pmids":["18939989"],"confidence":"Medium","gaps":["Upstream signals controlling promoter activity in vivo not defined","Does not connect expression to muscle substrates"]},{"year":2010,"claim":"Connected the death axis to immune regulation and cancer: NAD+-driven ART2.2-mediated P2X7 activation depletes Tregs, and this can be exploited for antitumor immunity.","evidence":"NAD+ injection in ART2-KO and P2X7-KO mice, tumor models, and ART2.2-specific single-domain antibody protection","pmids":["20975043"],"confidence":"High","gaps":["Mechanism of preferential Treg susceptibility not fully defined","ART2.2 is the mouse ortholog, not human ART1"]},{"year":2014,"claim":"Uncovered an atypical intracellular role: human ARTC1 in the ER ADP-ribosylates the chaperone GRP78/BiP during ER stress, coupling the enzyme to translational control.","evidence":"Immunofluorescence co-localization, macro-domain pull-down, and ER stress induction with ARTC1 overexpression","pmids":["25292337"],"confidence":"Medium","gaps":["GRP78 modification site not mapped","Functional consequence for the unfolded protein response not established"]},{"year":2018,"claim":"Defined the in vivo muscle substrate repertoire, showing ARTC1 mediates arginine ADP-ribosylation of hundreds of surface/extracellular proteins including hemopexin.","evidence":"MS-based ADP-ribosylome profiling of WT vs ARTC1-KO myotubes and tissues with site-specific identification","pmids":["30110646"],"confidence":"High","gaps":["Functional consequence of most modified targets unknown","Which substrates drive muscle phenotypes not resolved"]},{"year":2022,"claim":"Established tumor-cell ART1 as a direct immune-evasion effector that kills P2X7R+ CD8 T cells, validating it as a therapeutic target.","evidence":"In vitro NICD assay, genetic ART1 KO in tumor lines, antibody blockade in syngeneic NSCLC/melanoma models, and CD8 depletion","pmids":["35294260"],"confidence":"High","gaps":["Whether tumor ART1 acts enzymatically in cis or trans not fully resolved","Source of extracellular NAD+ in the tumor microenvironment not defined"]},{"year":2024,"claim":"Identified VAPB-Arg50 as an intracellular ARTC1 substrate linked to calcium homeostasis and established hARTC3 as a stabilizing binding partner that promotes ARTC1 activity.","evidence":"Co-IP, ADP-ribosylation site mapping, hARTC1 knockdown, and calcium homeostasis assays","pmids":["37381178"],"confidence":"Medium","gaps":["Mechanism by which VAPB modification alters calcium not defined","hARTC3 stabilization mechanism not structurally characterized"]},{"year":2023,"claim":"Linked ARTC1 to suppression of necroptosis and modulation of spontaneous tumorigenesis and cardiac injury in vivo.","evidence":"Artc1-KO and Artc1/Arh1-double-KO mice, xenografts, ischemia-reperfusion and echocardiography (preprint)","pmids":["36945646"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Direct substrate coupling ARTC1 to RIP3/necroptosis not identified","Tissue-specific contributions not dissected"]},{"year":null,"claim":"It remains unresolved how ARTC1's distinct compartments (cell surface, secreted, and ER-luminal) and its mono- vs poly-ADP-ribosylation activities are coordinated, and which specific arginine-modified substrates mediate its muscle, necroptosis-suppressive, and calcium-homeostatic functions.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structure of human ART1 itself","Substrate-to-phenotype causality largely uncharted","Regulation distinguishing intracellular ER activity from ecto-activity unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[3,13,9]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[13,12,19]},{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[9]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[3,4,15]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[13,5]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[12]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[0,6,7,15]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[13,12]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[0,20]}],"complexes":[],"partners":["P2X7","ARTC3","VAPB","GRP78/HSPA5","ITGA7"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P52961","full_name":"GPI-linked NAD(P)(+)--arginine ADP-ribosyltransferase 1","aliases":["ADP-ribosyltransferase C2 and C3 toxin-like 1","ARTC1","Mono(ADP-ribosyl)transferase 1"],"length_aa":327,"mass_kda":36.3,"function":"Has ADP-ribosyltransferase activity toward GLP1R","subcellular_location":"Sarcoplasmic reticulum membrane","url":"https://www.uniprot.org/uniprotkb/P52961/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ART1","classification":"Not Classified","n_dependent_lines":9,"n_total_lines":1208,"dependency_fraction":0.0074503311258278145},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ART1","total_profiled":1310},"omim":[{"mim_id":"610624","title":"ADP-RIBOSYLSERINE HYDROLASE; ADPRS","url":"https://www.omim.org/entry/610624"},{"mim_id":"610620","title":"ADP-RIBOSYLHYDROLASE-LIKE 1; ADPRHL1","url":"https://www.omim.org/entry/610620"},{"mim_id":"603853","title":"TETRASPANIN 32; TSPAN32","url":"https://www.omim.org/entry/603853"},{"mim_id":"603086","title":"ADP-RIBOSYLTRANSFERASE 3; ART3","url":"https://www.omim.org/entry/603086"},{"mim_id":"601625","title":"ADP-RIBOSYLTRANSFERASE 1; ART1","url":"https://www.omim.org/entry/601625"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"skeletal muscle","ntpm":44.4},{"tissue":"tongue","ntpm":34.3}],"url":"https://www.proteinatlas.org/search/ART1"},"hgnc":{"alias_symbol":["ART2","CD296","ARTC1"],"prev_symbol":[]},"alphafold":{"accession":"P52961","domains":[{"cath_id":"3.90.176.10","chopping":"36-100_107-287","consensus_level":"medium","plddt":94.2913,"start":36,"end":287}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P52961","model_url":"https://alphafold.ebi.ac.uk/files/AF-P52961-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P52961-F1-predicted_aligned_error_v6.png","plddt_mean":84.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ART1","jax_strain_url":"https://www.jax.org/strain/search?query=ART1"},"sequence":{"accession":"P52961","fasta_url":"https://rest.uniprot.org/uniprotkb/P52961.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P52961/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P52961"}},"corpus_meta":[{"pmid":"23453459","id":"PMC_23453459","title":"Effects of interleukin-1 blockade with anakinra on adverse cardiac remodeling and heart failure after acute myocardial infarction [from the Virginia Commonwealth University-Anakinra Remodeling Trial (2) (VCU-ART2) pilot study].","date":"2013","source":"The American journal of cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/23453459","citation_count":329,"is_preprint":false},{"pmid":"14563321","id":"PMC_14563321","title":"NAD-induced T cell death: ADP-ribosylation of cell surface proteins by ART2 activates the cytolytic P2X7 purinoceptor.","date":"2003","source":"Immunity","url":"https://pubmed.ncbi.nlm.nih.gov/14563321","citation_count":288,"is_preprint":false},{"pmid":"19880795","id":"PMC_19880795","title":"A zinc finger transcription factor ART1 regulates multiple genes implicated in aluminum tolerance in rice.","date":"2009","source":"The Plant cell","url":"https://pubmed.ncbi.nlm.nih.gov/19880795","citation_count":247,"is_preprint":false},{"pmid":"20975043","id":"PMC_20975043","title":"Extracellular NAD+ shapes the Foxp3+ regulatory T cell compartment through the ART2-P2X7 pathway.","date":"2010","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/20975043","citation_count":176,"is_preprint":false},{"pmid":"25482680","id":"PMC_25482680","title":"Comparative safety of interleukin-1 blockade with anakinra in patients with ST-segment elevation acute myocardial infarction (from the VCU-ART and VCU-ART2 pilot studies).","date":"2014","source":"The American journal of cardiology","url":"https://pubmed.ncbi.nlm.nih.gov/25482680","citation_count":137,"is_preprint":false},{"pmid":"17579037","id":"PMC_17579037","title":"NAD+ released during inflammation participates in T cell homeostasis by inducing ART2-mediated death of naive T cells in vivo.","date":"2007","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/17579037","citation_count":136,"is_preprint":false},{"pmid":"15728473","id":"PMC_15728473","title":"Recognition of a new ARTC1 peptide ligand uniquely expressed in tumor cells by antigen-specific CD4+ regulatory T cells.","date":"2005","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/15728473","citation_count":122,"is_preprint":false},{"pmid":"17575259","id":"PMC_17575259","title":"Single domain antibodies from llama effectively and specifically block T cell ecto-ADP-ribosyltransferase ART2.2 in vivo.","date":"2007","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/17575259","citation_count":98,"is_preprint":false},{"pmid":"21502187","id":"PMC_21502187","title":"Identification of a cis-acting element of ART1, a C2H2-type zinc-finger transcription factor for aluminum tolerance in rice.","date":"2011","source":"Plant physiology","url":"https://pubmed.ncbi.nlm.nih.gov/21502187","citation_count":82,"is_preprint":false},{"pmid":"30110646","id":"PMC_30110646","title":"Proteomic Characterization of the Heart and Skeletal Muscle Reveals Widespread Arginine ADP-Ribosylation by the ARTC1 Ectoenzyme.","date":"2018","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/30110646","citation_count":59,"is_preprint":false},{"pmid":"25292337","id":"PMC_25292337","title":"ARTC1-mediated ADP-ribosylation of GRP78/BiP: a new player in endoplasmic-reticulum stress responses.","date":"2014","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/25292337","citation_count":55,"is_preprint":false},{"pmid":"12270706","id":"PMC_12270706","title":"Structure of the ecto-ADP-ribosyl transferase ART2.2 from rat.","date":"2002","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/12270706","citation_count":53,"is_preprint":false},{"pmid":"15657180","id":"PMC_15657180","title":"Activity and specificity of toxin-related mouse T cell ecto-ADP-ribosyltransferase ART2.2 depends on its association with lipid rafts.","date":"2005","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/15657180","citation_count":52,"is_preprint":false},{"pmid":"11035085","id":"PMC_11035085","title":"Metalloprotease-mediated shedding of enzymatically active mouse ecto-ADP-ribosyltransferase ART2.2 upon T cell activation.","date":"2000","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/11035085","citation_count":47,"is_preprint":false},{"pmid":"12370300","id":"PMC_12370300","title":"Generation and characterization of ecto-ADP-ribosyltransferase ART2.1/ART2.2-deficient mice.","date":"2002","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/12370300","citation_count":44,"is_preprint":false},{"pmid":"35294260","id":"PMC_35294260","title":"Expression of the mono-ADP-ribosyltransferase ART1 by tumor cells mediates immune resistance in non-small cell lung cancer.","date":"2022","source":"Science translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35294260","citation_count":40,"is_preprint":false},{"pmid":"29888411","id":"PMC_29888411","title":"Functional characterization of an aluminum (Al)-inducible transcription factor, ART2, revealed a different pathway for Al tolerance in rice.","date":"2018","source":"The New phytologist","url":"https://pubmed.ncbi.nlm.nih.gov/29888411","citation_count":40,"is_preprint":false},{"pmid":"26456718","id":"PMC_26456718","title":"Transcription factor ART1 mediates starch hydrolysis and mycotoxin production in Fusarium graminearum and F. verticillioides.","date":"2015","source":"Molecular plant pathology","url":"https://pubmed.ncbi.nlm.nih.gov/26456718","citation_count":37,"is_preprint":false},{"pmid":"10331639","id":"PMC_10331639","title":"The RT6 (Art2) family of ADP-ribosyltransferases in rat and mouse.","date":"1999","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10331639","citation_count":28,"is_preprint":false},{"pmid":"24335275","id":"PMC_24335275","title":"ART1 silencing enhances apoptosis of mouse CT26 cells via the PI3K/Akt/NF-κB pathway.","date":"2013","source":"Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/24335275","citation_count":28,"is_preprint":false},{"pmid":"19796917","id":"PMC_19796917","title":"A recombinant heavy chain antibody approach blocks ART2 mediated deletion of an iNKT cell population that upon activation inhibits autoimmune diabetes.","date":"2009","source":"Journal of autoimmunity","url":"https://pubmed.ncbi.nlm.nih.gov/19796917","citation_count":28,"is_preprint":false},{"pmid":"30610170","id":"PMC_30610170","title":"Methionine triggers Ppz-mediated dephosphorylation of Art1 to promote cargo-specific endocytosis.","date":"2019","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/30610170","citation_count":25,"is_preprint":false},{"pmid":"17947697","id":"PMC_17947697","title":"Lipopolysaccharide, IFN-gamma, and IFN-beta induce expression of the thiol-sensitive ART2.1 Ecto-ADP-ribosyltransferase in murine macrophages.","date":"2007","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/17947697","citation_count":25,"is_preprint":false},{"pmid":"16931513","id":"PMC_16931513","title":"ART2, a T cell surface mono-ADP-ribosyltransferase, generates extracellular poly(ADP-ribose).","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16931513","citation_count":24,"is_preprint":false},{"pmid":"25473118","id":"PMC_25473118","title":"Regulation of Rho-GEF Rgf3 by the arrestin Art1 in fission yeast cytokinesis.","date":"2014","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/25473118","citation_count":24,"is_preprint":false},{"pmid":"36515424","id":"PMC_36515424","title":"ART1 and putrescine contribute to rice aluminum resistance via OsMYB30 in cell wall modification.","date":"2023","source":"Journal of integrative plant biology","url":"https://pubmed.ncbi.nlm.nih.gov/36515424","citation_count":21,"is_preprint":false},{"pmid":"31245663","id":"PMC_31245663","title":"ALUMINUM RESISTANCE TRANSCRIPTION FACTOR 1 (ART1) contributes to natural variation in aluminum resistance in diverse genetic backgrounds of rice (O. sativa).","date":"2017","source":"Plant direct","url":"https://pubmed.ncbi.nlm.nih.gov/31245663","citation_count":21,"is_preprint":false},{"pmid":"9841866","id":"PMC_9841866","title":"Molecular characterization and expression of the gene for mouse NAD+:arginine ecto-mono(ADP-ribosyl)transferase, Art1.","date":"1998","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/9841866","citation_count":19,"is_preprint":false},{"pmid":"19404775","id":"PMC_19404775","title":"Basal and inducible expression of the thiol-sensitive ART2.1 ecto-ADP-ribosyltransferase in myeloid and lymphoid leukocytes.","date":"2009","source":"Purinergic signalling","url":"https://pubmed.ncbi.nlm.nih.gov/19404775","citation_count":19,"is_preprint":false},{"pmid":"22457937","id":"PMC_22457937","title":"Biochemical identification of rat ART-1 and Ly-1 alloantigens.","date":"1980","source":"Immunogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/22457937","citation_count":18,"is_preprint":false},{"pmid":"26373733","id":"PMC_26373733","title":"Tubb3 regulation by the Erk and Akt signaling pathways: a mechanism involved in the effect of arginine ADP-ribosyltransferase 1 (Art1) on apoptosis of colon carcinoma CT26 cells.","date":"2015","source":"Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/26373733","citation_count":17,"is_preprint":false},{"pmid":"31658248","id":"PMC_31658248","title":"Yeast α-arrestin Art2 is the key regulator of ubiquitylation-dependent endocytosis of plasma membrane vitamin B1 transporters.","date":"2019","source":"PLoS biology","url":"https://pubmed.ncbi.nlm.nih.gov/31658248","citation_count":16,"is_preprint":false},{"pmid":"29508376","id":"PMC_29508376","title":"Blocking the ART2.2/P2X7-system is essential to avoid a detrimental bias in functional CD4 T cell studies.","date":"2018","source":"European journal of immunology","url":"https://pubmed.ncbi.nlm.nih.gov/29508376","citation_count":16,"is_preprint":false},{"pmid":"26307000","id":"PMC_26307000","title":"Evaluation of the expression and function of the P2X7 receptor and ART1 in human regulatory T-cell subsets.","date":"2015","source":"Immunobiology","url":"https://pubmed.ncbi.nlm.nih.gov/26307000","citation_count":15,"is_preprint":false},{"pmid":"28138708","id":"PMC_28138708","title":"Effect of ART1 on the proliferation and migration of mouse colon carcinoma CT26 cells in vivo.","date":"2017","source":"Molecular medicine reports","url":"https://pubmed.ncbi.nlm.nih.gov/28138708","citation_count":15,"is_preprint":false},{"pmid":"11396961","id":"PMC_11396961","title":"A hematopoietic-specific transmembrane protein, Art-1, is possibly regulated by AML1.","date":"2001","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/11396961","citation_count":15,"is_preprint":false},{"pmid":"22781627","id":"PMC_22781627","title":"NAD induces astrocyte calcium flux and cell death by ART2 and P2X7 pathway.","date":"2012","source":"The American journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/22781627","citation_count":14,"is_preprint":false},{"pmid":"25973293","id":"PMC_25973293","title":"ART1 promotes starvation-induced autophagy: a possible protective role in the development of colon carcinoma.","date":"2015","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/25973293","citation_count":14,"is_preprint":false},{"pmid":"18939989","id":"PMC_18939989","title":"Identification of two regulatory binding sites which confer myotube specific expression of the mono-ADP-ribosyltransferase ART1 gene.","date":"2008","source":"BMC molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/18939989","citation_count":12,"is_preprint":false},{"pmid":"15033737","id":"PMC_15033737","title":"Triggering of T-cell apoptosis by toxin-related ecto-ADP-ribosyltransferase ART2.","date":"2003","source":"Annals of the New York Academy of Sciences","url":"https://pubmed.ncbi.nlm.nih.gov/15033737","citation_count":9,"is_preprint":false},{"pmid":"38504172","id":"PMC_38504172","title":"ART1 knockdown decreases the IL-6-induced proliferation of colorectal cancer cells.","date":"2024","source":"BMC cancer","url":"https://pubmed.ncbi.nlm.nih.gov/38504172","citation_count":8,"is_preprint":false},{"pmid":"11683379","id":"PMC_11683379","title":"Levels of Art2+ cells but not soluble Art2 protein correlate with expression of autoimmune diabetes in the BB rat.","date":"2001","source":"Autoimmunity","url":"https://pubmed.ncbi.nlm.nih.gov/11683379","citation_count":8,"is_preprint":false},{"pmid":"12077446","id":"PMC_12077446","title":"Expression, purification, crystallization and preliminary X-ray analysis of rat ecto-ADP-ribosyltransferase 2 (ART2.2).","date":"2002","source":"Acta crystallographica. Section D, Biological crystallography","url":"https://pubmed.ncbi.nlm.nih.gov/12077446","citation_count":8,"is_preprint":false},{"pmid":"38069359","id":"PMC_38069359","title":"Overexpression of an ART1-Interacting Gene OsNAC016 Improves Al Tolerance in Rice.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/38069359","citation_count":7,"is_preprint":false},{"pmid":"30403748","id":"PMC_30403748","title":"Investigation of Ldb19/Art1 localization and function at the late Golgi.","date":"2018","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/30403748","citation_count":7,"is_preprint":false},{"pmid":"18838822","id":"PMC_18838822","title":"Articulospora sp. produces Art1, an inhibitor of bacterial histidine kinase.","date":"2008","source":"Bioscience, biotechnology, and biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18838822","citation_count":7,"is_preprint":false},{"pmid":"11508269","id":"PMC_11508269","title":"Changing patterns of cell surface mono (ADP-ribosyl) transferase antigen ART2.2 on resting versus cytopathically-activated T cells in NOD/Lt mice.","date":"2001","source":"Diabetologia","url":"https://pubmed.ncbi.nlm.nih.gov/11508269","citation_count":6,"is_preprint":false},{"pmid":"37337792","id":"PMC_37337792","title":"Art2 mediates selective endocytosis of methionine transporters during adaptation to sphingolipid depletion.","date":"2023","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/37337792","citation_count":6,"is_preprint":false},{"pmid":"38911388","id":"PMC_38911388","title":"Pan-Cancer Analysis of ART1 and its Potential Value in Gastric Cancer.","date":"2024","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/38911388","citation_count":5,"is_preprint":false},{"pmid":"21641039","id":"PMC_21641039","title":"Transgenic overexpression of toxin-related ecto-ADP-ribosyltransferase ART2.2 sensitizes T cells but not B cells to NAD-induced cell death.","date":"2011","source":"Molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/21641039","citation_count":4,"is_preprint":false},{"pmid":"37381178","id":"PMC_37381178","title":"ARTC1-mediated VAPB ADP-ribosylation regulates calcium homeostasis.","date":"2024","source":"Journal of molecular cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/37381178","citation_count":3,"is_preprint":false},{"pmid":"26314564","id":"PMC_26314564","title":"Evidence of a role for S. cerevisiae α-arrestin Art1 (Ldb19) in mating projection and zygote formations.","date":"2015","source":"Cell biology international","url":"https://pubmed.ncbi.nlm.nih.gov/26314564","citation_count":3,"is_preprint":false},{"pmid":"40864788","id":"PMC_40864788","title":"Computational Exploration of Bacterial Compounds Targeting Arginine-Specific Mono-Adp-Ribosyl-Transferase 1 (Art1): A Pathway to Novel Therapeutic Anticancer Strategies.","date":"2025","source":"Current issues in molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/40864788","citation_count":3,"is_preprint":false},{"pmid":"11292261","id":"PMC_11292261","title":"Fetal thymi from diabetes-prone but not diabetes-resistant BB/Wor rats fail to generate mature ART2+ T-cells in organ culture.","date":"2001","source":"Cellular and molecular biology (Noisy-le-Grand, France)","url":"https://pubmed.ncbi.nlm.nih.gov/11292261","citation_count":2,"is_preprint":false},{"pmid":"40653961","id":"PMC_40653961","title":"Comparative Transcriptome Reveals ART1-Dependent Regulatory Pathways for Fe Toxicity Response in Rice Roots.","date":"2025","source":"Physiologia plantarum","url":"https://pubmed.ncbi.nlm.nih.gov/40653961","citation_count":1,"is_preprint":false},{"pmid":"41361964","id":"PMC_41361964","title":"Role of Art1 in Sperm Damage Induced by Type 2 Diabetes Mellitus.","date":"2025","source":"Molecular reproduction and development","url":"https://pubmed.ncbi.nlm.nih.gov/41361964","citation_count":0,"is_preprint":false},{"pmid":"36945646","id":"PMC_36945646","title":"Mono-ADP-ribosyltransferase 1 ( Artc1 )-deficiency decreases tumorigenesis, increases inflammation, decreases cardiac contractility, and reduces survival.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/36945646","citation_count":0,"is_preprint":false},{"pmid":"16195877","id":"PMC_16195877","title":"Characterization of multiple alleles of the T-cell differentiation marker ART2 (RT6) in inbred and wild rats.","date":"2005","source":"Immunogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/16195877","citation_count":0,"is_preprint":false},{"pmid":"16453289","id":"PMC_16453289","title":"Substrate specificity of soluble and membrane-associated ADP-ribosyltransferase ART2.1.","date":"2006","source":"Journal of cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16453289","citation_count":0,"is_preprint":false},{"pmid":"41346334","id":"PMC_41346334","title":"Effect of ART1 on the efficacy of oxaliplatin in colorectal cancer under high-cholesterol conditions.","date":"2025","source":"Histology and histopathology","url":"https://pubmed.ncbi.nlm.nih.gov/41346334","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":32099,"output_tokens":5840,"usd":0.091949,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":14408,"output_tokens":4578,"usd":0.093245,"stage2_stop_reason":"end_turn"},"total_usd":0.185194,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2003,\n      \"finding\": \"ART2 (ARTC1 family)-catalyzed ADP-ribosylation of P2X7 purinoceptor on T cell surfaces activates the receptor, causing calcium flux, pore formation, phosphatidylserine exposure, shedding of CD62L, cell shrinkage, and propidium iodide uptake, establishing NAD-induced T cell death (NICD) via the ART2-P2X7 axis.\",\n      \"method\": \"Cell-based assays (flow cytometry, propidium iodide uptake, calcium flux), pharmacological inhibition, and ART2-deficient T cells\",\n      \"journal\": \"Immunity\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal functional readouts, ART2-deficient controls, replicated by subsequent independent studies\",\n      \"pmids\": [\"14563321\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Crystal structure of rat ART2.2 (ortholog of ART1 family) determined at 1.7 Å resolution; the active center was identified by a bound nicotinamide analogue revealing induced-fit upon substrate binding, and the NAD+ binding mode was modeled. Two disulfide bridges distant from the active center stabilize the protein. The fold places ART2.2 in a distinct subfamily of ADP-ribosyltransferases.\",\n      \"method\": \"X-ray crystallography (1.7 Å), ligand soaking with nicotinamide analogue, structural modeling of NAD+ binding\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with active-site ligand and functional modeling, peer-reviewed\",\n      \"pmids\": [\"12270706\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"ART2.1/ART2.2 double-knockout T cells exhibit dramatically reduced ADP-ribosylation of cell surface proteins and are completely resistant to NAD-induced apoptosis and partially resistant to NAD-mediated suppression of proliferation, demonstrating that the ART2 ectoenzymes are essential for NAD-mediated T cell regulation.\",\n      \"method\": \"Genetic knockout mice, flow cytometry-based ADP-ribosylation assay, T cell proliferation and apoptosis assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean double-KO with multiple orthogonal readouts, peer-reviewed\",\n      \"pmids\": [\"12370300\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Mouse Art1 encodes a GPI-anchored ecto-enzyme predominantly expressed in cardiac and skeletal muscle. Recombinant Art1 expressed as an IgG1-Fc fusion exhibits arginine-specific ADP-ribosyltransferase activity in vitro.\",\n      \"method\": \"Northern blot, RT-PCR, recombinant expression in 293T cells, enzymatic activity assay\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct enzymatic activity assay in single lab with molecular characterization\",\n      \"pmids\": [\"9841866\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"ART2.2 activity and substrate specificity depend on its GPI anchor-mediated association with lipid rafts: GPI-anchored ART2.2 showed >10-fold higher activity at limiting NAD concentrations and ADP-ribosylated a restricted set of target proteins compared to transmembrane-anchored ART2.2. Disruption of lipid rafts broadened substrate specificity. Auto-ADP-ribosylation of ART2.2 itself required GPI anchoring and raft association.\",\n      \"method\": \"Lymphoma transfectants expressing GPI- vs. transmembrane-anchored ART2.2, enzymatic activity assays, cholesterol depletion (cyclodextrin), detergent solubilization\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (transfectants, lipid raft disruption, activity assays), mechanistic comparison of two ART2.2 variants\",\n      \"pmids\": [\"15657180\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"ART2.2 is shed from the T cell surface in enzymatically active form upon T cell activation via metalloprotease-mediated cleavage close to its membrane anchor (similar to TNF-alpha converting enzyme/ADAM17 cleavage of CD62L). Shed ART2.2 ADP-ribosylates substrates in vitro, and shedding correlates with reduced ADP-ribosylation capacity of the T cell surface.\",\n      \"method\": \"FACS-based ADP-ribosylation assay, metalloprotease inhibitor (Immunex Compound 3), SDS-PAGE, in vitro ADP-ribosylation assay\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological inhibitor + functional assay in single lab\",\n      \"pmids\": [\"11035085\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"NAD+ released during acute inflammation in vivo induces ART2- and P2X7-dependent depletion of naive T cells in draining lymph nodes, preferentially targeting naive over recently activated/memory T cells. This effect was absent in ART2-deficient mice, demonstrating ART2's essential role in inflammation-induced T cell homeostasis in vivo.\",\n      \"method\": \"In vivo inflammation model (polyacrylamide beads), intravenous NAD+ injection, ART2-KO and CD38-KO mice, flow cytometry, antibody response assay\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO controls, in vivo model, multiple functional readouts across independent mouse strains\",\n      \"pmids\": [\"17579037\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Regulatory T cells (Treg) express high levels of ART2.2 and P2X7; ART2.2-mediated ADP-ribosylation of P2X7 by extracellular NAD+ depletes Tregs in vivo. Selective depletion of Tregs by systemic NAD+ administration promotes antitumor responses in mouse tumor models. An inhibitory ART2.2-specific single-domain antibody protects Tregs from NAD+-induced effects.\",\n      \"method\": \"Intravenous NAD+ injection in mice, flow cytometry, ART2-KO and P2X7-KO mice, single-domain antibody blocking, tumor models\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple KO strains, in vivo tumor models, antibody blockade, replicated across multiple tumor models\",\n      \"pmids\": [\"20975043\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Single-domain antibodies (VHH) from llama immunized against ART2.2 specifically block ART2.2 enzymatic and cytotoxic activities in vivo within 15 min of intravenous injection, with blockade reversible within 24 h. The blocking was specific for ART2.2 and did not affect the related enzymes ART1 or ART2.1.\",\n      \"method\": \"Llama immunization, VHH generation, intravenous injection in mice, flow cytometry-based ADP-ribosylation and cell death assays\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo functional blockade with specificity controls, single lab\",\n      \"pmids\": [\"17575259\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ART2 (rat T cell surface isoform) catalyzes formation of extracellular poly(ADP-ribose) rather than solely mono-ADP-ribosylation; auto-ADP-ribosylation at Arg-185 produces ADP-ribose polymer identified by PR-AMP detection via HPLC and MS/MS. Intestinal intraepithelial lymphocyte ART2 undergoes multimeric auto-ADP-ribosylation more efficiently than peripheral T cell ART2, correlating with greater resistance to NAD-induced cell death.\",\n      \"method\": \"Purified recombinant ART2, sequencing gel, HPLC, MS/MS mass spectrometry, site-directed identification of Arg-185\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with multiple analytical methods (HPLC, MS/MS, sequencing gel) in single lab\",\n      \"pmids\": [\"16931513\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"LPS, IFN-gamma, and IFN-beta selectively induce expression of ART2.1 (but not ART2.2) as a GPI-anchored cell surface ectoenzyme in bone marrow-derived macrophages. The catalytic function of induced ART2.1 requires extracellular thiol-reducing cofactors (allosteric disulfide bond regulation). Induction is blocked by inhibitors of NF-κB, PI3K, and JAK-STAT pathways but potentiated by ERK1/2 inhibition.\",\n      \"method\": \"BMDM isolation, LPS/IFN stimulation, flow cytometry, pharmacological pathway inhibitors, ADP-ribosylation activity assay with thiol reductants\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct enzymatic activity measurements with pathway inhibitors, single lab\",\n      \"pmids\": [\"17947697\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"ART1 gene expression in skeletal muscle is driven by cooperative binding of myogenin to an E-box and MEF-2 to an A/T-rich element in the proximal promoter (~1.3 kb upstream of TSS). Mutation of either element nearly abolishes promoter inducibility. Gel mobility shift assays confirmed binding of myogenin and MEF-2 restricted to myotubes.\",\n      \"method\": \"Promoter deletion analysis, luciferase reporter assay in C2C12 and C3H-10T1/2 cells, site-directed mutagenesis of E-box and A/T-rich element, gel mobility shift assay (EMSA) with nuclear extracts\",\n      \"journal\": \"BMC molecular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis + EMSA + reporter assay, single lab\",\n      \"pmids\": [\"18939989\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Human ARTC1 localizes to the endoplasmic reticulum (ER) — unlike other GPI-anchored ARTC family members — and ADP-ribosylates the ER luminal chaperone GRP78/BiP. ARTC1 is activated during ER stress, resulting in acute ADP-ribosylation of GRP78/BiP coinciding with translational inhibition.\",\n      \"method\": \"Immunofluorescence co-localization, macro-domain pull-down to identify ADP-ribosylated proteins, overexpression of ARTC1, ER stress induction, co-localization with GRP78/BiP\",\n      \"journal\": \"Cellular and molecular life sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — macro-domain binding module + immunofluorescence + ER stress induction, single lab\",\n      \"pmids\": [\"25292337\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ARTC1 ADP-ribosylates hundreds of arginine-containing proteins on the cell surface and in the extracellular space of skeletal muscle and heart tissue, as determined by mass spectrometry comparing wild-type and ARTC1-deficient mice. Hemopexin (HPX) was validated as an ARTC1 substrate. Target proteins are associated with signal transduction, transmembrane transport, and muscle function.\",\n      \"method\": \"Mass spectrometry-based ADP-ribosylome profiling of C2C12 myotubes and tissues from WT vs. ARTC1-KO mice, site-specific identification of arginine ADP-ribosylation\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — proteome-wide MS with KO controls, multiple orthogonal validations, substrate site identification\",\n      \"pmids\": [\"30110646\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"ARTC1 peptide ligands derived from mutated tumor cell proteins are presented by MHC class II and specifically recognized by tumor-infiltrating CD4+ regulatory T cell clones, which then suppress proliferation and IL-2 secretion of melanoma-reactive T cells. Tumor cells (but not tumor lysate-pulsed B cells) directly activate these Treg clones.\",\n      \"method\": \"Establishment of CD4+ Treg clones from TILs, antigen identification by expression cloning, T cell suppression assay (proliferation, IL-2 secretion), tumor cell co-culture\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional T cell clones, antigen identification, suppression assay, single lab\",\n      \"pmids\": [\"15728473\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ART1 expressed on tumor cell membranes mediates ADP-ribosylation and NICD of P2X7R+ CD8 T cells, reducing their infiltration into non-small cell lung cancer. Genetic or antibody-mediated ART1 inhibition in murine NSCLC and melanoma models slowed tumor growth in a CD8 T cell-dependent manner and increased P2X7R+CD8 T cell tumor infiltration.\",\n      \"method\": \"In vitro NICD assay with P2X7R+CD8 T cells, genetic ART1 KO in tumor cell lines, antibody-mediated ART1 blockade in syngeneic mouse tumor models, CD8 T cell depletion experiments, flow cytometry\",\n      \"journal\": \"Science translational medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO + antibody blockade + CD8 depletion, multiple tumor models, mechanistic in vitro confirmation\",\n      \"pmids\": [\"35294260\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ART1 silencing in mouse CT26 colon carcinoma cells enhances cisplatin-induced apoptosis, correlating with reduced phospho-Akt(Thr308), reduced phospho-IκBα, reduced NF-κB p65 nuclear translocation, decreased Bcl-2 and Bcl-xL expression, and increased Bax expression.\",\n      \"method\": \"Lentiviral shRNA knockdown of ART1, flow cytometry (apoptosis), Western blot (Akt, IκBα, NF-κB, Bcl-2 family proteins)\",\n      \"journal\": \"Cellular physiology and biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — KD with defined pathway readouts, single lab, multiple markers measured\",\n      \"pmids\": [\"24335275\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"ART1 knockdown or overexpression in CT26 colon carcinoma cells modulates Akt and Erk signaling pathway activity and expression of βIII-tubulin (Tubb3), which acts downstream of both Akt and Erk to influence apoptosis. Inhibiting either Akt or Erk downregulates Tubb3 at protein and mRNA levels, placing Tubb3 as a convergent downstream effector.\",\n      \"method\": \"Lentiviral KD and OE of ART1, in vivo allograft transplant model, Western blot, pathway inhibitors (Akt and Erk inhibitors), mRNA analysis\",\n      \"journal\": \"Tumour biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, KD/OE with pathway inhibitors but no direct ART1-substrate identification\",\n      \"pmids\": [\"26373733\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"ART1 overexpression promotes starvation-induced autophagy in CT26 colon carcinoma cells via a pathway involving increased Rac1, NF-κB, PARP-1, LKB1, and p-AMPK and decreased p-P70S6K. ART1 co-immunoprecipitates with integrin α7 in these cells.\",\n      \"method\": \"Lentiviral OE and KD, electron microscopy and LC3B Western blot (autophagy), Co-IP (ART1–integrin α7), pharmacological inhibitors (Rac1, PARP-1)\",\n      \"journal\": \"American journal of cancer research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, Co-IP without reciprocal validation, pathway inhibitors without direct mechanistic mapping to ART1 enzymatic function\",\n      \"pmids\": [\"25973293\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ARTC1 ADP-ribosylates VAPB at Arg50, and knockdown of hARTC1 impairs intracellular calcium homeostasis. hARTC3 interacts with hARTC1 and stabilizes it, promoting its enzymatic activity.\",\n      \"method\": \"Co-IP (hARTC3–hARTC1 interaction), ADP-ribosylation site mapping (Arg50 of VAPB), hARTC1 knockdown, calcium homeostasis assay\",\n      \"journal\": \"Journal of molecular cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — site-specific ADP-ribosylation mapping, Co-IP, functional calcium assay, single lab\",\n      \"pmids\": [\"37381178\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In ARTC1-KO and Artc1/Arh1 double-KO mice, spontaneous tumorigenesis is decreased and multi-organ inflammation with TNF-α upregulation is increased. In xenograft models, tumorigenicity of Arh1-KO MEFs was decreased in Artc1-KO hosts, with increased CD8+ T cell and macrophage tumor infiltration and necroptosis. Artc1-KO male mice exhibit reduced myocardial contractility and enhanced susceptibility to ischemia-reperfusion injury with increased RIP3 protein levels, suggesting ARTC1 suppresses necroptosis in heart.\",\n      \"method\": \"Artc1-KO and Artc1/Arh1-double-KO mice, spontaneous tumor monitoring, xenograft model, echocardiography/MRI, ischemia-reperfusion model, Western blot (RIP3, TNF-α), flow cytometry (immune infiltrates)\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple KO models, orthogonal readouts, but preprint not yet peer-reviewed\",\n      \"pmids\": [\"36945646\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ART2.1 substrate specificity is altered by the protein's membrane vs. solution environment: detergent solubilization or GPI-anchor cleavage by PI-PLC changes the spectrum of histone proteins ADP-ribosylated. Soluble ART2.1 in serum ADP-ribosylates albumin and transferrin, identified by mass spectrometry.\",\n      \"method\": \"Phospholipase C treatment, detergent solubilization, in vitro ADP-ribosylation with [32P]-NAD, SDS-PAGE, mass spectrometry identification of substrates\",\n      \"journal\": \"Journal of cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzymatic assay with MS substrate identification, single lab\",\n      \"pmids\": [\"16453289\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ART1/ARTC1 is a GPI-anchored, arginine-specific ecto-ADP-ribosyltransferase expressed predominantly in skeletal and cardiac muscle (and, upon induction, in immune cells) that transfers ADP-ribose from extracellular NAD+ to arginine residues on cell surface and extracellular target proteins — including P2X7 purinoceptor (activating it to induce T cell death), integrin α7, hemopexin, and VAPB — with enzyme activity and substrate specificity modulated by GPI-anchor-dependent lipid raft association, thiol-redox status (ART2.1 isoform), metalloprotease-mediated ectodomain shedding, and interaction with hARTC3; in muscle tissue ARTC1 mediates widespread arginine ADP-ribosylation of extracellular proteins and suppresses necroptosis, while on immune cells its NAD-dependent ADP-ribosylation of P2X7 controls T cell and regulatory T cell homeostasis and constitutes a tumor immune-evasion mechanism.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ART1/ARTC1 is a GPI-anchored, arginine-specific ecto-ADP-ribosyltransferase, predominantly expressed in cardiac and skeletal muscle, that transfers ADP-ribose from extracellular NAD+ onto arginine residues of cell-surface and extracellular target proteins [#3, #13]. In muscle tissue it carries out widespread arginine ADP-ribosylation of hundreds of extracellular and surface proteins, including the validated substrate hemopexin, modifying targets linked to signal transduction, transmembrane transport, and muscle function [#13]. Muscle-restricted ARTC1 expression is driven by cooperative binding of myogenin to an E-box and MEF-2 to an A/T-rich element in the proximal promoter [#11]. The closely related ARTC1-family ectoenzyme ART2 ADP-ribosylates the P2X7 purinoceptor on T cells, activating it to trigger calcium flux, pore formation, phosphatidylserine exposure, and NAD-induced cell death (NICD), a pathway abolished in ART2-deficient T cells [#0, #2]; in vivo this axis depletes naive T cells during inflammation and depletes P2X7-high regulatory T cells, with Treg depletion promoting antitumor responses [#6, #7]. On tumor cells, ART1 itself ADP-ribosylates P2X7R+ CD8 T cells to drive their NICD and exclude them from tumors, constituting an immune-evasion mechanism whose genetic or antibody blockade slows tumor growth in a CD8-dependent manner [#15]. Enzyme activity and substrate specificity are controlled by GPI-anchor-dependent lipid-raft association, which restricts substrate range and supports auto-ADP-ribosylation, and by metalloprotease-mediated ectodomain shedding of active enzyme from the cell surface [#4, #5]. A subset of human ARTC1 localizes atypically to the endoplasmic reticulum where it ADP-ribosylates the chaperone GRP78/BiP during ER stress [#12], and it modifies VAPB at Arg50 to influence calcium homeostasis, with hARTC3 binding and stabilizing ARTC1 to promote its activity [#19].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established the molecular identity of the gene product: that mouse Art1 is a GPI-anchored ecto-enzyme with intrinsic arginine-specific ADP-ribosyltransferase activity expressed in muscle.\",\n      \"evidence\": \"Northern/RT-PCR expression profiling and recombinant IgG1-Fc fusion enzymatic activity assay in 293T cells\",\n      \"pmids\": [\"9841866\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vitro substrates not physiological\", \"No structure or active-site mapping\", \"Muscle function of the enzyme not addressed\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Resolved the catalytic architecture and demonstrated, genetically, that family ectoenzymes are required for NAD-mediated T cell regulation.\",\n      \"evidence\": \"1.7 \\u00c5 crystal structure of rat ART2.2 with nicotinamide-analogue ligand, plus ART2.1/2.2 double-KO T cell apoptosis and proliferation assays\",\n      \"pmids\": [\"12270706\", \"12370300\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure is of ART2.2 ortholog, not ART1 itself\", \"Surface substrate driving T cell death not yet identified at this step\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Identified the effector substrate of NAD-induced T cell death, defining the ART2\\u2013P2X7 axis as the mechanism converting extracellular NAD+ into a death signal.\",\n      \"evidence\": \"Flow cytometry, calcium flux, PI uptake, pharmacological inhibition, and ART2-deficient T cells\",\n      \"pmids\": [\"14563321\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"ADP-ribosylated arginine site on P2X7 not mapped here\", \"Did not address ART1 enzyme specifically\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Defined how GPI-anchor-dependent lipid raft localization tunes enzyme activity and narrows substrate specificity.\",\n      \"evidence\": \"GPI- vs transmembrane-anchored ART2.2 transfectants with cholesterol depletion and activity assays\",\n      \"pmids\": [\"15657180\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Raft composition mediating specificity not defined\", \"Generalization to ART1 in muscle not shown\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Showed enzyme abundance at the cell surface is dynamically regulated by metalloprotease-mediated shedding, decoupling enzyme location from activity.\",\n      \"evidence\": \"FACS ADP-ribosylation assay with metalloprotease inhibitor and in vitro activity of shed enzyme\",\n      \"pmids\": [\"11035085\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific protease not genetically confirmed\", \"Physiological consequence of shed soluble enzyme unclear\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Revealed catalytic versatility \\u2014 poly(ADP-ribose) formation and auto-modification at Arg-185 \\u2014 and linked auto-modification to cell-death resistance, while showing membrane environment reshapes substrate choice.\",\n      \"evidence\": \"Purified recombinant ART2 with HPLC, MS/MS, PI-PLC and detergent solubilization assays\",\n      \"pmids\": [\"16931513\", \"16453289\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Findings on ART2/ART2.1 orthologs, not human ART1\", \"Physiological relevance of extracellular poly(ADP-ribose) unresolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Demonstrated in vivo that the NAD+/ART2/P2X7 axis controls T cell homeostasis during inflammation and that the enzyme is inducible and redox-regulated in myeloid cells, while establishing blocking antibodies as tools.\",\n      \"evidence\": \"In vivo inflammation and NAD+ injection in ART2-KO/CD38-KO mice, BMDM induction assays, and VHH single-domain antibody blockade\",\n      \"pmids\": [\"17579037\", \"17947697\", \"17575259\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"ART2.1 thiol-redox regulation mechanism at the structural level not resolved\", \"Distinction between ART1 and ART2 roles in vivo not parsed\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Explained the muscle-restricted expression of ART1 through a defined myogenic transcriptional program.\",\n      \"evidence\": \"Promoter deletion/mutagenesis, luciferase reporters in myoblasts/myotubes, and EMSA for myogenin and MEF-2\",\n      \"pmids\": [\"18939989\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Upstream signals controlling promoter activity in vivo not defined\", \"Does not connect expression to muscle substrates\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Connected the death axis to immune regulation and cancer: NAD+-driven ART2.2-mediated P2X7 activation depletes Tregs, and this can be exploited for antitumor immunity.\",\n      \"evidence\": \"NAD+ injection in ART2-KO and P2X7-KO mice, tumor models, and ART2.2-specific single-domain antibody protection\",\n      \"pmids\": [\"20975043\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of preferential Treg susceptibility not fully defined\", \"ART2.2 is the mouse ortholog, not human ART1\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Uncovered an atypical intracellular role: human ARTC1 in the ER ADP-ribosylates the chaperone GRP78/BiP during ER stress, coupling the enzyme to translational control.\",\n      \"evidence\": \"Immunofluorescence co-localization, macro-domain pull-down, and ER stress induction with ARTC1 overexpression\",\n      \"pmids\": [\"25292337\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"GRP78 modification site not mapped\", \"Functional consequence for the unfolded protein response not established\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined the in vivo muscle substrate repertoire, showing ARTC1 mediates arginine ADP-ribosylation of hundreds of surface/extracellular proteins including hemopexin.\",\n      \"evidence\": \"MS-based ADP-ribosylome profiling of WT vs ARTC1-KO myotubes and tissues with site-specific identification\",\n      \"pmids\": [\"30110646\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of most modified targets unknown\", \"Which substrates drive muscle phenotypes not resolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Established tumor-cell ART1 as a direct immune-evasion effector that kills P2X7R+ CD8 T cells, validating it as a therapeutic target.\",\n      \"evidence\": \"In vitro NICD assay, genetic ART1 KO in tumor lines, antibody blockade in syngeneic NSCLC/melanoma models, and CD8 depletion\",\n      \"pmids\": [\"35294260\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether tumor ART1 acts enzymatically in cis or trans not fully resolved\", \"Source of extracellular NAD+ in the tumor microenvironment not defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified VAPB-Arg50 as an intracellular ARTC1 substrate linked to calcium homeostasis and established hARTC3 as a stabilizing binding partner that promotes ARTC1 activity.\",\n      \"evidence\": \"Co-IP, ADP-ribosylation site mapping, hARTC1 knockdown, and calcium homeostasis assays\",\n      \"pmids\": [\"37381178\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which VAPB modification alters calcium not defined\", \"hARTC3 stabilization mechanism not structurally characterized\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Linked ARTC1 to suppression of necroptosis and modulation of spontaneous tumorigenesis and cardiac injury in vivo.\",\n      \"evidence\": \"Artc1-KO and Artc1/Arh1-double-KO mice, xenografts, ischemia-reperfusion and echocardiography (preprint)\",\n      \"pmids\": [\"36945646\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Direct substrate coupling ARTC1 to RIP3/necroptosis not identified\", \"Tissue-specific contributions not dissected\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved how ARTC1's distinct compartments (cell surface, secreted, and ER-luminal) and its mono- vs poly-ADP-ribosylation activities are coordinated, and which specific arginine-modified substrates mediate its muscle, necroptosis-suppressive, and calcium-homeostatic functions.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structure of human ART1 itself\", \"Substrate-to-phenotype causality largely uncharted\", \"Regulation distinguishing intracellular ER activity from ecto-activity unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [3, 13, 9]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [13, 12, 19]},\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [3, 4, 15]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [13, 5]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [12]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [0, 6, 7, 15]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [13, 12]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [0, 20]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"P2X7\", \"ARTC3\", \"VAPB\", \"GRP78/HSPA5\", \"ITGA7\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":6,"faith_total":7,"faith_pct":85.71428571428571}}