{"gene":"GPX1","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":1997,"finding":"Mitochondrial GPX1 is encoded by the Gpx1 gene. Gpx1 knockout mice show no detectable GPX activity in either cytosol or mitochondria of liver, establishing that the Gpx1 gene encodes both the cytosolic and mitochondrial forms of glutathione peroxidase.","method":"Subcellular fractionation (Percoll gradient) of Gpx1 knockout and wild-type mouse liver; enzyme activity assay with H2O2 and cumene hydroperoxide as substrates; electron microscopy to confirm fraction purity","journal":"Archives of biochemistry and biophysics","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct enzymatic assay in knockout vs wild-type with rigorous fractionation controls, single lab but unambiguous loss-of-function result","pmids":["9126277"],"is_preprint":false},{"year":1998,"finding":"GPX1 protects against acute oxidative stress in vivo: Gpx1 knockout mice are hypersensitive to the oxidant paraquat (100% lethality at doses non-lethal to wild-type) and cortical neurons from Gpx1 knockout mice are more susceptible to H2O2-induced cell death.","method":"In vivo paraquat challenge in Gpx1 (-/-) knockout mice; primary cortical neuron H2O2 exposure assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean genetic knockout with defined in vivo and in vitro phenotypic readouts; replicated across multiple dose levels","pmids":["9712879"],"is_preprint":false},{"year":2000,"finding":"GPX1 loss increases noise-induced cochlear damage: Gpx1 knockout mice show significantly greater noise-induced hearing loss and increased cochlear hair cell and nerve fiber loss compared to wild-type controls, establishing a protective role of GPX1 in the cochlea.","method":"Auditory brainstem response (ABR) threshold measurement; cochlear histology in Gpx1 knockout mice after broadband noise exposure","journal":"Journal of the Association for Research in Otolaryngology : JARO","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean knockout with defined audiological and histological readouts, single lab","pmids":["11545230"],"is_preprint":false},{"year":2001,"finding":"Combined deficiency of GPX1 and GPX2 (double knockout) causes spontaneous inflammatory bowel disease with ileocolitis, elevated myeloperoxidase activity, and lipid hydroperoxides in the colon mucosa, whereas single knockouts of either Gpx1 or Gpx2 alone do not produce this phenotype under standard conditions.","method":"Genetic double-knockout mouse model; histological examination; myeloperoxidase activity assay; lipid hydroperoxide measurement","journal":"American journal of physiology. Gastrointestinal and liver physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis via double-knockout with multiple orthogonal readouts; demonstrates functional redundancy between GPX1 and GPX2 in intestinal mucosa","pmids":["11518697"],"is_preprint":false},{"year":2004,"finding":"GPX1 deficiency leads to senescence-like changes in fibroblasts, including reduced proliferative capacity, elevated Cip1 levels, increased NF-κB activation, and increased susceptibility to H2O2-induced apoptosis, demonstrating that GPX1-mediated H2O2 removal is required for normal cell cycle progression and survival.","method":"Fibroblasts derived from Gpx1 knockout mice; proliferation assays; DNA synthesis measurement; Western blotting for Cip1; NF-κB activation assay; dose-response H2O2 apoptosis assay","journal":"Free radical biology & medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean knockout fibroblasts with multiple cellular readouts, single lab","pmids":["14732290"],"is_preprint":false},{"year":2005,"finding":"Homocysteine decreases GPX1 protein expression and activity by inhibiting the selenocysteine incorporation mechanism required for translating the UGA codon, without affecting GPX1 mRNA levels. This was shown using a UGA-luciferase reporter containing GPX1 or GPX3 SECIS elements.","method":"Luciferase UGA read-through reporter assay with GPX1/GPX3 SECIS elements; folate antagonist (aminopterin/HAT/Met) treatment to elevate cellular homocysteine; enzyme activity assay; quantitative mRNA and protein measurement","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with reporter system and pharmacological manipulation, multiple orthogonal methods (activity, mRNA, protein), single lab","pmids":["15734734"],"is_preprint":false},{"year":2005,"finding":"GPX1 overexpression reduces Bax mRNA and protein levels (by ~43-46%) without affecting Bcl-2 or p53 levels in endothelial cells, thereby lowering the Bax/Bcl-2 apoptotic ratio at baseline.","method":"Stable transfection of GPX1 cDNA in ECV304 endothelial cells; quantitative RT-PCR; Western blot for Bax, Bcl-2, and p53","journal":"Molecular and cellular biochemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — overexpression with protein/mRNA quantification, two orthogonal methods, single lab","pmids":["16132718"],"is_preprint":false},{"year":2008,"finding":"GPX1 knockout reduces gap junction coupling conductance in the lens (72% of normal in outer fibers, 45% in inner core), reduces connexin 46 and connexin 50 protein levels by ~50%, and causes accumulation of Ca2+ and Na+ in the lens core, establishing GPX1 as required for normal lens gap junction function.","method":"Whole-lens impedance studies; osmotic swelling of fiber cell membrane vesicles; Fura-2 and SBFI microinjection to measure [Ca2+]i and [Na+]i; quantitative Western blot for Cx46, Cx50, and AQP0","journal":"The Journal of membrane biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — multiple orthogonal methods (electrophysiology, ion imaging, quantitative Western blot) in knockout vs wild-type, single lab","pmids":["19067024"],"is_preprint":false},{"year":2009,"finding":"GPX1 is O-GlcNAc modified on its C-terminus under hyperglycemic conditions, and this O-GlcNAcylation is required for GPX1 activation and for GPX1 binding to c-Abl and Arg kinases. Pharmacological increase of O-GlcNAc in vivo (using the O-GlcNAcase inhibitor NTZ) induces GPX1 activation in mouse liver.","method":"O-GlcNAc immunoprecipitation and site mapping; co-immunoprecipitation of GPX1 with c-Abl and Arg; in vivo NTZ injection in mice with GPX1 activity measurement","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP for binding partners, in vivo pharmacological evidence, direct PTM identification, single lab","pmids":["19944066"],"is_preprint":false},{"year":2010,"finding":"GPX1 knockout specifically elevates islet hydroperoxide levels and upregulates p53 phosphorylation, and GPX1-deficient mice show decreased plasma insulin and reduced islet β-cell mass without blocking glucose-stimulated insulin secretion (in contrast to SOD1 knockout), establishing a distinct role of H2O2 vs. superoxide in pancreatic function.","method":"GPX1 single and double knockout mouse models; islet superoxide and hydroperoxide measurements; blood glucose and plasma insulin assays; p53 phosphorylation Western blot; epistasis with SOD1 knockout","journal":"Antioxidants & redox signaling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis (double knockout), multiple biochemical readouts, single lab","pmids":["20586612"],"is_preprint":false},{"year":2012,"finding":"The transcription factor TFAP2C (but not TFAP2A) directly binds an AP-2 regulatory element in the GPX1 promoter and is required for GPX1 expression. GPX1 promoter CpG island methylation prevents TFAP2C binding, and demethylation with 5'-aza-dC restores TFAP2C binding and GPX1 expression.","method":"ChIP-seq for TFAP2C in breast cancer cell lines; TFAP2C knockdown with measurement of GPX1 mRNA/protein; GPX1 promoter methylation analysis; 5'-aza-dC treatment and ChIP; GPX1 overexpression with t-butyl hydroperoxide resistance assay","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1 / Moderate — ChIP-seq plus loss-of-function knockdown plus pharmacological demethylation, multiple orthogonal approaches in single study","pmids":["22964634"],"is_preprint":false},{"year":2012,"finding":"ZNF143 transcription factor upregulates GPX1 activity in mitochondrial respiratory-defective cells, promoting cell survival under oxidative stress. ZNF143 also activates SepSecS (required for selenocysteine tRNA synthesis), increasing the selenocysteine synthesis pathway.","method":"ZNF143 and GPX1 knockdown in mitochondrial respiratory-defective cells; GPX1 activity assay; measurement of GSH, GCLC, GCLM, and SepSecS expression; cisplatin sensitivity assay","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — dual knockdown epistasis, enzymatic activity and gene expression measurements, single lab","pmids":["23152058"],"is_preprint":false},{"year":2013,"finding":"GPX1 deficiency exacerbates retinopathy of prematurity: GPX1 knockout mice exposed to hyperoxia-hypoxia show larger retinal avascular areas, increased neovascularization, elevated VEGF expression, increased nitrotyrosine, and increased superoxide compared to wild-type ROP mice.","method":"GPX1 knockout mice in oxygen-induced retinopathy model; retinal histology; qRT-PCR for VEGF; immunolabeling for nitrotyrosine and superoxide","journal":"Investigative ophthalmology & visual science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockout in disease model with multiple orthogonal readouts, single lab","pmids":["23287791"],"is_preprint":false},{"year":2014,"finding":"RORα (retinoic acid-related orphan receptor α) transcriptionally induces GPX1 expression through RORα response elements located in the upstream promoter of the Gpx1 gene, thereby reducing hepatic oxidative stress.","method":"RORα overexpression and cholesterol sulfate (agonist) treatment in primary hepatocytes; qRT-PCR measurement of GPX1 mRNA; promoter analysis identifying RORα response elements","journal":"Antioxidants & redox signaling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain-of-function with promoter element identification, single lab","pmids":["24597775"],"is_preprint":false},{"year":2014,"finding":"GPX1 translation is regulated by the mTOR pathway: rapamycin (mTOR inhibitor) elevates GPX1 protein levels independently of mRNA levels, indicating mTOR suppresses selenocysteine-containing GPX1 translation.","method":"Treatment of CML cell lines with rapamycin; GPX1 protein quantification by Western blot; mRNA steady-state level measurement","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — pharmacological inhibition with protein/mRNA dissociation, single lab, mechanism inferred","pmids":["24691473"],"is_preprint":false},{"year":2016,"finding":"CUEDC2 promotes TRIM33-mediated ubiquitination and proteasomal degradation of GPX1, suppressing GPX1 protein levels in cardiomyocytes. Loss of CUEDC2 increases GPX1 protein, enhances ROS scavenging, and reduces infarct size after ischemia/reperfusion injury.","method":"Cuedc2 knockout mice; Co-IP to show CUEDC2–TRIM33 and TRIM33–GPX1 interactions; ubiquitination assay; Western blot for GPX1; in vivo I/R injury model with infarct size measurement","journal":"EMBO molecular medicine","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstitution of ubiquitination pathway with Co-IP, ubiquitination assay, and in vivo knockout phenotype, multiple orthogonal methods","pmids":["27286733"],"is_preprint":false},{"year":2017,"finding":"GPX1 knockdown in ATDC5 chondrogenic cells impairs chondrogenic differentiation (reduced Sox9, collagen II, aggrecan expression; reduced GAG accumulation) primarily through induction of reductive stress (elevated GSH/GSSG ratio) rather than through antioxidant ROS removal, as the impaired chondrogenesis was rescued by the thiol-oxidizing agent diamide but not by the antioxidant NAC.","method":"shRNA-mediated GPX1 knockdown in ATDC5 cells; measurement of ROS, GSH/GSSG ratio; alcian blue staining for GAGs; rescue experiments with diamide (thiol-oxidizer) and NAC","journal":"Acta biochimica et biophysica Sinica","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with pharmacological rescue dissecting mechanism, multiple readouts, single lab","pmids":["28039148"],"is_preprint":false},{"year":2017,"finding":"hucMSC exosome-derived GPX1 protein is delivered to recipient hepatocytes and is required for the antioxidant and hepatoprotective effects of these exosomes; knockdown of GPX1 in donor hucMSCs abrogates the antioxidant and anti-apoptotic capacity of the exosomes both in vitro and in vivo.","method":"GPX1 knockdown in hucMSCs; exosome isolation and administration in CCl4 liver injury mouse model; measurement of oxidative stress markers, apoptosis, and liver function in vitro and in vivo","journal":"Molecular therapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function in donor cells with in vitro and in vivo phenotypic readouts, single lab","pmids":["28089078"],"is_preprint":false},{"year":2020,"finding":"PER1 physically interacts with GPX1 in the cytoplasm and enhances GPX1 activity, thereby improving mitochondrial oxidative phosphorylation efficiency. Per1 deficiency impairs daily mitochondrial dynamics and deregulates cellular GPx-related ROS fluctuations in peripheral organs.","method":"Co-immunoprecipitation (PER1/GPX1 interaction); Per1 knockout mice; oxygen consumption rhythm measurement; GPx activity assay; mitochondrial function assays","journal":"Redox biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP for physical interaction plus knockout phenotype with functional enzymatic readout, single lab","pmids":["32896721"],"is_preprint":false},{"year":2021,"finding":"CCL5 signaling increases GPX1 expression and reduces intracellular ROS in neurons; CCL5 knockout mice after mild TBI show reduced GPX1 activity, increased ROS, and impaired hippocampal memory recovery that can be rescued by intranasal recombinant CCL5 or N-acetylcysteine.","method":"CCL5 knockout mice with weight-drop TBI model; behavioral testing (Novel object recognition, Barnes Maze); NADPH oxidase activity; GPX1 activity assay; GPX1 overexpression in SHSY5Y cells; NAC and recombinant CCL5 rescue","journal":"Redox biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockout plus pharmacological and recombinant protein rescue, multiple orthogonal readouts, single lab","pmids":["34315111"],"is_preprint":false},{"year":2022,"finding":"The splicing factor NONO, in association with PSPC1, binds a consensus motif in the intron of GPX1 pre-mRNA and promotes its correct splicing. NONO knockdown causes GPX1 intron retention, reducing functional GPX1 protein, impairing redox homeostasis and promoting apoptosis in glioblastoma cells.","method":"RNA sequencing of NONO-knockdown GBM cells; RIP-PCR and RNA pulldown to show NONO binding to GPX1 pre-mRNA intron; JC-1 staining and Seahorse assay for redox homeostasis; in vivo orthotopic xenograft model","journal":"Theranostics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct RNA pulldown identifying binding site, transcriptomic validation, in vivo model, single lab","pmids":["35910786"],"is_preprint":false},{"year":2022,"finding":"DNMT2-mediated DNA methylation of the GPX1 promoter reduces GPX1 expression in AGE-exposed cardiomyocytes; selenium supplementation suppresses DNMT2 expression, reduces GPX1 promoter methylation, restores GPX1 expression/activity, and protects against AGE-induced cardiac dysfunction.","method":"Rat primary myocyte exposure to AGEs; bisulfite sequencing PCR of GPX1 promoter; DNMT inhibitor (AZA) and selenium supplementation; GPX1 activity and protein measurements; cardiac function evaluation in rat model","journal":"Oxidative medicine and cellular longevity","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct promoter methylation analysis with pharmacological rescue, in vitro and in vivo, single lab","pmids":["35432721"],"is_preprint":false},{"year":2022,"finding":"TRIM8 protein interacts with GPX1 and promotes GPX1 ubiquitination, leading to reduced GPX1 protein levels in cardiomyocytes; TRIM8 knockdown partially alleviates I/R-induced cardiomyocyte injury, and GPX1 knockdown abolishes the cardioprotective effect of salvianolic acid B.","method":"Co-IP of TRIM8 and GPX1; ubiquitination assay; TRIM8 knockdown/overexpression in AC16 cardiomyocytes; GPX1 knockdown rescue experiment; in vivo rat I/R model","journal":"Pharmaceutical biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, ubiquitination assay, epistasis experiment with knockdown, single lab","pmids":["35968584"],"is_preprint":false},{"year":2023,"finding":"HIF-1α binds directly to the GPX1 promoter under hypoxic conditions to increase GPX1 expression, enabling glioblastoma cells to detoxify excess H2O2 caused by hypoxia. GPX1 depletion causes H2O2 overload and apoptosis in glioblastoma cells, and hypoxia also increases exosomal GPX1 that protects adjacent cells from H2O2 or radiation-induced apoptosis.","method":"HIF-1α ChIP on GPX1 promoter; GPX1 knockdown in glioblastoma cells; H2O2 measurement; apoptosis assay; exosome isolation and functional assays; glioblastoma xenograft model","journal":"Redox biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct ChIP demonstrating HIF-1α binding to GPX1 promoter, loss-of-function with mechanistic readout, in vivo xenograft, multiple orthogonal methods","pmids":["37572455"],"is_preprint":false},{"year":2023,"finding":"GPX1 deficiency increases H2O2 levels that activate NF-κB p65, which upregulates renal angiotensin II type 1 receptor (AT1R) expression, causing sodium retention and hypertension in selenium-deficient rats. Ebselen (GPX1 mimetic), GPX1 silencing + NF-κB inhibitor (PDTC) experiments confirmed the GPx1/H2O2/NF-κB/AT1R pathway.","method":"Selenium-deficient rat model; GPx1 silencing in renal proximal tubule cells; NF-κB inhibitor PDTC; ebselen treatment; AT1R expression and Na+-K+-ATPase activity measurements; nuclear translocation of NF-κB p65","journal":"Free radical biology & medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pathway established by multiple pharmacological and genetic loss-of-function interventions in cells and in vivo, single lab","pmids":["36868433"],"is_preprint":false},{"year":2024,"finding":"GPX1 undergoes S-palmitoylation at cysteine residues 76 and 113; PPT1 (palmitoyl-protein thioesterase 1) mediates GPX1 depalmitoylation and reduces GPX1 protein stability. Inhibiting GPX1 palmitoylation (via PPT1 expression or non-palmitoylated mutant) enhances neovascular angiogenesis, while enhancing palmitoylation (PPT1 inhibition with DC661) suppresses retinal angiogenesis in an oxygen-induced retinopathy model.","method":"Palmitoylation site mapping at Cys-76 and Cys-113 by mutagenesis; PPT1 knockout and overexpression; non-palmitoylated Gpx1 mutant expression; oxygen-induced retinopathy mouse model; angiogenesis assays","journal":"Redox biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — site-directed mutagenesis identifying palmitoylation sites, genetic and pharmacological manipulation, in vivo disease model, multiple approaches in single study","pmids":["39423458"],"is_preprint":false}],"current_model":"GPX1 is a selenocysteine-containing peroxidase that reduces H2O2 and lipid peroxides using glutathione as cofactor; it is encoded by a single gene that produces both cytosolic and mitochondrial isoforms, is translationally regulated by selenium availability (via SECIS-mediated UGA read-through), mTOR, and homocysteine, is transcriptionally controlled by TFAP2C, RORα, and HIF-1α, and is post-translationally regulated by O-GlcNAcylation (which activates it and promotes binding to c-Abl/Arg kinases), ubiquitination (promoted by the CUEDC2–TRIM33 and TRIM8 axes), promoter DNA methylation (by DNMT2/DNMT3a/b), and S-palmitoylation at Cys-76 and Cys-113 (modulated by PPT1); functionally, GPX1 protects against acute oxidative stress, ischemia-reperfusion injury, neurodegeneration, retinopathy, and colitis, regulates gap junction integrity in the lens, modulates the Bax/Bcl-2 apoptotic ratio, influences chondrogenic differentiation through redox balance, and controls angiogenesis via palmitoylation-dependent stability."},"narrative":{"mechanistic_narrative":"GPX1 is a selenocysteine-containing glutathione peroxidase that detoxifies hydrogen peroxide and lipid hydroperoxides, serving as a central defense against acute oxidative stress in vivo [PMID:9126277, PMID:9712879]. A single Gpx1 gene encodes both the cytosolic and mitochondrial enzyme, and its loss eliminates detectable GPX activity in both compartments [PMID:9126277]. Genetic ablation renders mice hypersensitive to the oxidant paraquat and sensitizes neurons to H2O2-induced death [PMID:9712879], and GPX1-dependent peroxide removal is required for fibroblast proliferation and survival, where its loss provokes Cip1 elevation, NF-κB activation, and a senescence-like state [PMID:14732290]. Across multiple tissues GPX1 is protective: it limits noise-induced cochlear damage [PMID:11545230], maintains lens gap junction coupling through connexin 46/50 levels and ion homeostasis [PMID:19067024], constrains pancreatic islet hydroperoxide accumulation and p53 phosphorylation [PMID:20586612], and restrains retinal neovascularization in oxygen-induced retinopathy [PMID:23287791]; in the colon it acts redundantly with GPX2, since only the GPX1/GPX2 double knockout develops spontaneous ileocolitis [PMID:11518697]. GPX1 modulates apoptotic balance by lowering the Bax/Bcl-2 ratio [PMID:16132718], and in selenium deficiency its loss elevates H2O2 to activate an NF-κB–AT1R axis driving renal sodium retention and hypertension [PMID:36868433]. The enzyme is controlled at many levels: translation depends on selenocysteine UGA read-through that is impaired by homocysteine and suppressed by mTOR [PMID:15734734, PMID:24691473]; transcription is driven by TFAP2C, RORα, and hypoxic HIF-1α [PMID:22964634, PMID:24597775, PMID:37572455]; pre-mRNA splicing requires NONO/PSPC1 [PMID:35910786]; promoter activity is silenced by DNMT2-mediated CpG methylation [PMID:22964634, PMID:35432721]; and protein abundance is set by CUEDC2–TRIM33 and TRIM8 ubiquitin-mediated degradation as well as PPT1-regulated S-palmitoylation at Cys-76 and Cys-113 [PMID:27286733, PMID:35968584, PMID:39423458]. Post-translationally, O-GlcNAcylation activates GPX1 and promotes its binding to c-Abl and Arg kinases [PMID:19944066].","teleology":[{"year":1997,"claim":"Resolved whether the cytosolic and mitochondrial glutathione peroxidases derive from one gene, establishing the genetic identity of GPX1.","evidence":"Subcellular fractionation and enzyme activity assay in Gpx1 knockout vs wild-type mouse liver","pmids":["9126277"],"confidence":"High","gaps":["Does not address differential targeting mechanism to mitochondria vs cytosol","Single tissue (liver) examined"]},{"year":1998,"claim":"Demonstrated that GPX1 is physiologically required to survive acute oxidant challenge, moving it from a biochemical activity to an in vivo protective enzyme.","evidence":"Paraquat lethality in Gpx1 knockout mice and H2O2 sensitivity of knockout cortical neurons","pmids":["9712879"],"confidence":"High","gaps":["Does not define which downstream targets of peroxide damage are protected","Tissue-specific contributions not dissected"]},{"year":2001,"claim":"Revealed functional redundancy between GPX1 and GPX2 in the gut, explaining why single GPX1 loss is often phenotypically silent in some tissues.","evidence":"Spontaneous ileocolitis with elevated myeloperoxidase and lipid hydroperoxides only in Gpx1/Gpx2 double knockout mice","pmids":["11518697"],"confidence":"High","gaps":["Relative contribution of each isoform not quantified","Mechanism linking peroxide accumulation to inflammation not detailed"]},{"year":2005,"claim":"Established that GPX1 abundance is controlled at the level of selenocysteine UGA read-through, identifying homocysteine as a translational inhibitor independent of mRNA.","evidence":"UGA-luciferase SECIS reporter and folate-antagonist manipulation of homocysteine with activity/protein/mRNA readouts","pmids":["15734734"],"confidence":"High","gaps":["Molecular step in selenocysteine machinery targeted by homocysteine not pinpointed","In vivo relevance to disease states not tested here"]},{"year":2005,"claim":"Connected GPX1 to apoptotic regulation by showing it lowers the pro-apoptotic Bax/Bcl-2 ratio.","evidence":"GPX1 cDNA overexpression in ECV304 endothelial cells with Bax/Bcl-2/p53 RT-PCR and Western blot","pmids":["16132718"],"confidence":"Medium","gaps":["Overexpression-only; loss-of-function not tested","Mechanism linking peroxide removal to Bax transcription unknown"]},{"year":2008,"claim":"Extended GPX1 function beyond classical antioxidant defense to maintaining lens gap junction coupling and ion homeostasis.","evidence":"Whole-lens impedance, ion imaging, and quantitative Western blot for Cx46/Cx50 in Gpx1 knockout lenses","pmids":["19067024"],"confidence":"High","gaps":["Whether connexin loss is direct or oxidative-damage-mediated unresolved","Single-tissue specialization"]},{"year":2009,"claim":"Identified a post-translational activating modification, showing O-GlcNAcylation activates GPX1 and couples it to c-Abl/Arg kinase signaling under hyperglycemia.","evidence":"O-GlcNAc IP/site mapping, Co-IP with c-Abl and Arg, and in vivo NTZ-induced activation in mouse liver","pmids":["19944066"],"confidence":"Medium","gaps":["Functional consequence of c-Abl/Arg binding not defined","Co-IP without reciprocal structural validation of the modification site"]},{"year":2010,"claim":"Distinguished H2O2- from superoxide-dependent control of pancreatic function, placing GPX1 specifically upstream of islet p53 activation and beta-cell mass.","evidence":"Islet hydroperoxide/superoxide measurement and p53 phosphorylation in GPX1 vs SOD1 knockout mice","pmids":["20586612"],"confidence":"Medium","gaps":["Mechanism linking H2O2 to p53 phosphorylation not resolved","Single lab"]},{"year":2012,"claim":"Identified TFAP2C as a direct transcriptional activator of GPX1 and showed promoter CpG methylation silences GPX1 by blocking TFAP2C binding.","evidence":"ChIP-seq, TFAP2C knockdown, methylation analysis, and 5'-aza-dC demethylation in breast cancer cells","pmids":["22964634"],"confidence":"High","gaps":["Whether TFAP2C regulation operates outside breast cancer not tested","Methylation-writing enzyme not identified here"]},{"year":2012,"claim":"Showed ZNF143 upregulates GPX1 activity and the selenocysteine synthesis pathway to support survival of respiration-defective cells.","evidence":"ZNF143/GPX1 knockdown, activity assays, and SepSecS expression in mitochondrial respiratory-defective cells","pmids":["23152058"],"confidence":"Medium","gaps":["Direct ZNF143 promoter binding to GPX1 not demonstrated","Effect may be indirect via selenocysteine supply"]},{"year":2014,"claim":"Defined additional layers of GPX1 control: RORα as a transcriptional inducer and mTOR as a translational suppressor.","evidence":"RORα overexpression/agonist in hepatocytes with promoter element mapping; rapamycin protein/mRNA dissociation in CML cells","pmids":["24597775","24691473"],"confidence":"Medium","gaps":["mTOR effect on selenocysteine machinery inferred, not mapped to a step","RORα element function not validated by mutation"]},{"year":2016,"claim":"Reconstituted a ubiquitin-degradation pathway for GPX1, showing CUEDC2 drives TRIM33-mediated degradation that limits cardiac ROS scavenging.","evidence":"Cuedc2 knockout mice, Co-IP of CUEDC2-TRIM33-GPX1, ubiquitination assay, and in vivo I/R infarct measurement","pmids":["27286733"],"confidence":"High","gaps":["Ubiquitination site on GPX1 not mapped","Whether TRIM33 directly ubiquitinates GPX1 vs scaffolds another E3 unresolved"]},{"year":2017,"claim":"Showed GPX1-dependent reductive balance, rather than ROS removal alone, is required for chondrogenic differentiation.","evidence":"shRNA knockdown in ATDC5 cells with GSH/GSSG measurement and diamide-versus-NAC rescue","pmids":["28039148"],"confidence":"Medium","gaps":["Molecular targets of reductive stress in chondrogenesis unknown","Single cell-line model"]},{"year":2017,"claim":"Demonstrated GPX1 can act non-cell-autonomously, being delivered via exosomes to confer antioxidant and hepatoprotective effects on recipient cells.","evidence":"GPX1 knockdown in donor hucMSCs and exosome administration in CCl4 liver injury model","pmids":["28089078"],"confidence":"Medium","gaps":["Mechanism of GPX1 loading into exosomes not defined","Uptake/activity in recipient cells not quantified at enzyme level"]},{"year":2020,"claim":"Linked GPX1 to circadian and mitochondrial physiology via a direct interaction with the clock protein PER1 that enhances its activity.","evidence":"Co-IP of PER1-GPX1, Per1 knockout mice, and oxygen-consumption rhythm/GPx activity assays","pmids":["32896721"],"confidence":"Medium","gaps":["How PER1 binding mechanistically enhances GPX1 activity unknown","Single Co-IP without reciprocal mapping of interaction interface"]},{"year":2021,"claim":"Placed GPX1 downstream of CCL5 signaling in neuronal ROS control relevant to traumatic brain injury recovery.","evidence":"CCL5 knockout TBI mice with GPX1 activity, behavioral testing, and recombinant CCL5/NAC rescue","pmids":["34315111"],"confidence":"Medium","gaps":["Signaling steps linking CCL5 receptor to GPX1 expression not mapped","Whether CCL5 acts transcriptionally on GPX1 untested"]},{"year":2022,"claim":"Identified pre-mRNA splicing as a control point, with NONO/PSPC1 binding a GPX1 intron motif to ensure correct splicing and functional protein.","evidence":"RIP-PCR/RNA pulldown of NONO on GPX1 pre-mRNA and intron-retention readout in NONO-knockdown glioblastoma cells","pmids":["35910786"],"confidence":"Medium","gaps":["Direct PSPC1 contribution not separated from NONO","Generality of splicing dependence beyond glioblastoma untested"]},{"year":2022,"claim":"Added DNMT2-mediated promoter methylation and TRIM8-mediated ubiquitination as repressive controls on GPX1 in cardiomyocytes, and showed selenium reverses the methylation arm.","evidence":"Bisulfite sequencing and selenium/AZA rescue (DNMT2); Co-IP, ubiquitination assay, and I/R epistasis (TRIM8)","pmids":["35432721","35968584"],"confidence":"Medium","gaps":["TRIM8 ubiquitination site on GPX1 not mapped","Whether DNMT2 acts directly on the GPX1 promoter or via intermediaries unresolved"]},{"year":2023,"claim":"Established hypoxic induction of GPX1 by HIF-1α as a survival mechanism allowing tumor cells to detoxify hypoxia-driven H2O2, with exosomal GPX1 protecting neighboring cells.","evidence":"HIF-1α ChIP on GPX1 promoter, GPX1 knockdown with H2O2/apoptosis readouts, and glioblastoma xenografts","pmids":["37572455"],"confidence":"High","gaps":["Whether the same axis operates in non-malignant hypoxic tissue not tested","Mechanism of GPX1 exosomal sorting not defined"]},{"year":2023,"claim":"Defined a GPX1/H2O2/NF-κB/AT1R pathway linking selenium-dependent GPX1 loss to renal sodium handling and hypertension.","evidence":"Selenium-deficient rats, GPX1 silencing, NF-κB inhibitor and ebselen interventions with AT1R/Na+-K+-ATPase readouts","pmids":["36868433"],"confidence":"Medium","gaps":["Direct molecular link between H2O2 and p65 activation not specified","Single rodent model"]},{"year":2024,"claim":"Identified S-palmitoylation at Cys-76 and Cys-113 as a stability-regulating modification, with PPT1 depalmitoylation destabilizing GPX1 and modulating angiogenesis.","evidence":"Palmitoylation site mutagenesis, PPT1 knockout/overexpression and DC661 inhibition in an oxygen-induced retinopathy model","pmids":["39423458"],"confidence":"High","gaps":["Palmitoyl-transferase adding the modification not identified","How palmitoylation alters GPX1 stability mechanistically unresolved"]},{"year":null,"claim":"How the many transcriptional, translational, splicing, and post-translational controls of GPX1 are integrated to set enzyme dosage in a given cell type, and which are dominant in human disease, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified quantitative model of GPX1 regulation across regulators","Structural basis of GPX1 modification sites and partner binding not defined","Most disease links rest on single-lab rodent or cell models"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016491","term_label":"oxidoreductase activity","supporting_discovery_ids":[0,1,9]},{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[0,5]},{"term_id":"GO:0016209","term_label":"antioxidant activity","supporting_discovery_ids":[1,4,17]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,18]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,18]}],"pathway":[{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[1,4,23]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[10,13,23]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[5,15,22,25]}],"complexes":[],"partners":["C-ABL","ARG","TRIM33","CUEDC2","TRIM8","PER1","NONO","PPT1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P07203","full_name":"Glutathione peroxidase 1","aliases":["Cellular glutathione peroxidase","Phospholipid-hydroperoxide glutathione peroxidase GPX1"],"length_aa":203,"mass_kda":22.1,"function":"Catalyzes the reduction of hydroperoxides in a glutathione-dependent manner thus regulating cellular redox homeostasis (PubMed:11115402, PubMed:36608588). Can reduce small soluble hydroperoxides such as H2O2, cumene hydroperoxide and tert-butyl hydroperoxide, as well as several fatty acid-derived hydroperoxides (PubMed:11115402, PubMed:36608588). 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Brazilians.","date":"2016","source":"Nutrients","url":"https://pubmed.ncbi.nlm.nih.gov/27164132","citation_count":16,"is_preprint":false},{"pmid":"27286733","id":"PMC_27286733","title":"CUEDC2 modulates cardiomyocyte oxidative capacity by regulating GPX1 stability.","date":"2016","source":"EMBO molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/27286733","citation_count":16,"is_preprint":false},{"pmid":"38745588","id":"PMC_38745588","title":"Translational selenium nanoparticles boost GPx1 activation to reverse HAdV-14 virus-induced oxidative damage.","date":"2024","source":"Bioactive materials","url":"https://pubmed.ncbi.nlm.nih.gov/38745588","citation_count":15,"is_preprint":false},{"pmid":"26658762","id":"PMC_26658762","title":"DNA damage and oxidative stress response to selenium yeast in the non-smoking individuals: a short-term supplementation trial with respect to GPX1 and SEPP1 polymorphism.","date":"2015","source":"European journal of 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Gpx1 knockout mice show no detectable GPX activity in either cytosol or mitochondria of liver, establishing that the Gpx1 gene encodes both the cytosolic and mitochondrial forms of glutathione peroxidase.\",\n      \"method\": \"Subcellular fractionation (Percoll gradient) of Gpx1 knockout and wild-type mouse liver; enzyme activity assay with H2O2 and cumene hydroperoxide as substrates; electron microscopy to confirm fraction purity\",\n      \"journal\": \"Archives of biochemistry and biophysics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct enzymatic assay in knockout vs wild-type with rigorous fractionation controls, single lab but unambiguous loss-of-function result\",\n      \"pmids\": [\"9126277\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"GPX1 protects against acute oxidative stress in vivo: Gpx1 knockout mice are hypersensitive to the oxidant paraquat (100% lethality at doses non-lethal to wild-type) and cortical neurons from Gpx1 knockout mice are more susceptible to H2O2-induced cell death.\",\n      \"method\": \"In vivo paraquat challenge in Gpx1 (-/-) knockout mice; primary cortical neuron H2O2 exposure assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean genetic knockout with defined in vivo and in vitro phenotypic readouts; replicated across multiple dose levels\",\n      \"pmids\": [\"9712879\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"GPX1 loss increases noise-induced cochlear damage: Gpx1 knockout mice show significantly greater noise-induced hearing loss and increased cochlear hair cell and nerve fiber loss compared to wild-type controls, establishing a protective role of GPX1 in the cochlea.\",\n      \"method\": \"Auditory brainstem response (ABR) threshold measurement; cochlear histology in Gpx1 knockout mice after broadband noise exposure\",\n      \"journal\": \"Journal of the Association for Research in Otolaryngology : JARO\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean knockout with defined audiological and histological readouts, single lab\",\n      \"pmids\": [\"11545230\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Combined deficiency of GPX1 and GPX2 (double knockout) causes spontaneous inflammatory bowel disease with ileocolitis, elevated myeloperoxidase activity, and lipid hydroperoxides in the colon mucosa, whereas single knockouts of either Gpx1 or Gpx2 alone do not produce this phenotype under standard conditions.\",\n      \"method\": \"Genetic double-knockout mouse model; histological examination; myeloperoxidase activity assay; lipid hydroperoxide measurement\",\n      \"journal\": \"American journal of physiology. Gastrointestinal and liver physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis via double-knockout with multiple orthogonal readouts; demonstrates functional redundancy between GPX1 and GPX2 in intestinal mucosa\",\n      \"pmids\": [\"11518697\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"GPX1 deficiency leads to senescence-like changes in fibroblasts, including reduced proliferative capacity, elevated Cip1 levels, increased NF-κB activation, and increased susceptibility to H2O2-induced apoptosis, demonstrating that GPX1-mediated H2O2 removal is required for normal cell cycle progression and survival.\",\n      \"method\": \"Fibroblasts derived from Gpx1 knockout mice; proliferation assays; DNA synthesis measurement; Western blotting for Cip1; NF-κB activation assay; dose-response H2O2 apoptosis assay\",\n      \"journal\": \"Free radical biology & medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean knockout fibroblasts with multiple cellular readouts, single lab\",\n      \"pmids\": [\"14732290\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Homocysteine decreases GPX1 protein expression and activity by inhibiting the selenocysteine incorporation mechanism required for translating the UGA codon, without affecting GPX1 mRNA levels. This was shown using a UGA-luciferase reporter containing GPX1 or GPX3 SECIS elements.\",\n      \"method\": \"Luciferase UGA read-through reporter assay with GPX1/GPX3 SECIS elements; folate antagonist (aminopterin/HAT/Met) treatment to elevate cellular homocysteine; enzyme activity assay; quantitative mRNA and protein measurement\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with reporter system and pharmacological manipulation, multiple orthogonal methods (activity, mRNA, protein), single lab\",\n      \"pmids\": [\"15734734\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"GPX1 overexpression reduces Bax mRNA and protein levels (by ~43-46%) without affecting Bcl-2 or p53 levels in endothelial cells, thereby lowering the Bax/Bcl-2 apoptotic ratio at baseline.\",\n      \"method\": \"Stable transfection of GPX1 cDNA in ECV304 endothelial cells; quantitative RT-PCR; Western blot for Bax, Bcl-2, and p53\",\n      \"journal\": \"Molecular and cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — overexpression with protein/mRNA quantification, two orthogonal methods, single lab\",\n      \"pmids\": [\"16132718\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"GPX1 knockout reduces gap junction coupling conductance in the lens (72% of normal in outer fibers, 45% in inner core), reduces connexin 46 and connexin 50 protein levels by ~50%, and causes accumulation of Ca2+ and Na+ in the lens core, establishing GPX1 as required for normal lens gap junction function.\",\n      \"method\": \"Whole-lens impedance studies; osmotic swelling of fiber cell membrane vesicles; Fura-2 and SBFI microinjection to measure [Ca2+]i and [Na+]i; quantitative Western blot for Cx46, Cx50, and AQP0\",\n      \"journal\": \"The Journal of membrane biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — multiple orthogonal methods (electrophysiology, ion imaging, quantitative Western blot) in knockout vs wild-type, single lab\",\n      \"pmids\": [\"19067024\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"GPX1 is O-GlcNAc modified on its C-terminus under hyperglycemic conditions, and this O-GlcNAcylation is required for GPX1 activation and for GPX1 binding to c-Abl and Arg kinases. Pharmacological increase of O-GlcNAc in vivo (using the O-GlcNAcase inhibitor NTZ) induces GPX1 activation in mouse liver.\",\n      \"method\": \"O-GlcNAc immunoprecipitation and site mapping; co-immunoprecipitation of GPX1 with c-Abl and Arg; in vivo NTZ injection in mice with GPX1 activity measurement\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP for binding partners, in vivo pharmacological evidence, direct PTM identification, single lab\",\n      \"pmids\": [\"19944066\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"GPX1 knockout specifically elevates islet hydroperoxide levels and upregulates p53 phosphorylation, and GPX1-deficient mice show decreased plasma insulin and reduced islet β-cell mass without blocking glucose-stimulated insulin secretion (in contrast to SOD1 knockout), establishing a distinct role of H2O2 vs. superoxide in pancreatic function.\",\n      \"method\": \"GPX1 single and double knockout mouse models; islet superoxide and hydroperoxide measurements; blood glucose and plasma insulin assays; p53 phosphorylation Western blot; epistasis with SOD1 knockout\",\n      \"journal\": \"Antioxidants & redox signaling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis (double knockout), multiple biochemical readouts, single lab\",\n      \"pmids\": [\"20586612\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"The transcription factor TFAP2C (but not TFAP2A) directly binds an AP-2 regulatory element in the GPX1 promoter and is required for GPX1 expression. GPX1 promoter CpG island methylation prevents TFAP2C binding, and demethylation with 5'-aza-dC restores TFAP2C binding and GPX1 expression.\",\n      \"method\": \"ChIP-seq for TFAP2C in breast cancer cell lines; TFAP2C knockdown with measurement of GPX1 mRNA/protein; GPX1 promoter methylation analysis; 5'-aza-dC treatment and ChIP; GPX1 overexpression with t-butyl hydroperoxide resistance assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — ChIP-seq plus loss-of-function knockdown plus pharmacological demethylation, multiple orthogonal approaches in single study\",\n      \"pmids\": [\"22964634\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"ZNF143 transcription factor upregulates GPX1 activity in mitochondrial respiratory-defective cells, promoting cell survival under oxidative stress. ZNF143 also activates SepSecS (required for selenocysteine tRNA synthesis), increasing the selenocysteine synthesis pathway.\",\n      \"method\": \"ZNF143 and GPX1 knockdown in mitochondrial respiratory-defective cells; GPX1 activity assay; measurement of GSH, GCLC, GCLM, and SepSecS expression; cisplatin sensitivity assay\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — dual knockdown epistasis, enzymatic activity and gene expression measurements, single lab\",\n      \"pmids\": [\"23152058\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"GPX1 deficiency exacerbates retinopathy of prematurity: GPX1 knockout mice exposed to hyperoxia-hypoxia show larger retinal avascular areas, increased neovascularization, elevated VEGF expression, increased nitrotyrosine, and increased superoxide compared to wild-type ROP mice.\",\n      \"method\": \"GPX1 knockout mice in oxygen-induced retinopathy model; retinal histology; qRT-PCR for VEGF; immunolabeling for nitrotyrosine and superoxide\",\n      \"journal\": \"Investigative ophthalmology & visual science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout in disease model with multiple orthogonal readouts, single lab\",\n      \"pmids\": [\"23287791\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"RORα (retinoic acid-related orphan receptor α) transcriptionally induces GPX1 expression through RORα response elements located in the upstream promoter of the Gpx1 gene, thereby reducing hepatic oxidative stress.\",\n      \"method\": \"RORα overexpression and cholesterol sulfate (agonist) treatment in primary hepatocytes; qRT-PCR measurement of GPX1 mRNA; promoter analysis identifying RORα response elements\",\n      \"journal\": \"Antioxidants & redox signaling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain-of-function with promoter element identification, single lab\",\n      \"pmids\": [\"24597775\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"GPX1 translation is regulated by the mTOR pathway: rapamycin (mTOR inhibitor) elevates GPX1 protein levels independently of mRNA levels, indicating mTOR suppresses selenocysteine-containing GPX1 translation.\",\n      \"method\": \"Treatment of CML cell lines with rapamycin; GPX1 protein quantification by Western blot; mRNA steady-state level measurement\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — pharmacological inhibition with protein/mRNA dissociation, single lab, mechanism inferred\",\n      \"pmids\": [\"24691473\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CUEDC2 promotes TRIM33-mediated ubiquitination and proteasomal degradation of GPX1, suppressing GPX1 protein levels in cardiomyocytes. Loss of CUEDC2 increases GPX1 protein, enhances ROS scavenging, and reduces infarct size after ischemia/reperfusion injury.\",\n      \"method\": \"Cuedc2 knockout mice; Co-IP to show CUEDC2–TRIM33 and TRIM33–GPX1 interactions; ubiquitination assay; Western blot for GPX1; in vivo I/R injury model with infarct size measurement\",\n      \"journal\": \"EMBO molecular medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstitution of ubiquitination pathway with Co-IP, ubiquitination assay, and in vivo knockout phenotype, multiple orthogonal methods\",\n      \"pmids\": [\"27286733\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"GPX1 knockdown in ATDC5 chondrogenic cells impairs chondrogenic differentiation (reduced Sox9, collagen II, aggrecan expression; reduced GAG accumulation) primarily through induction of reductive stress (elevated GSH/GSSG ratio) rather than through antioxidant ROS removal, as the impaired chondrogenesis was rescued by the thiol-oxidizing agent diamide but not by the antioxidant NAC.\",\n      \"method\": \"shRNA-mediated GPX1 knockdown in ATDC5 cells; measurement of ROS, GSH/GSSG ratio; alcian blue staining for GAGs; rescue experiments with diamide (thiol-oxidizer) and NAC\",\n      \"journal\": \"Acta biochimica et biophysica Sinica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with pharmacological rescue dissecting mechanism, multiple readouts, single lab\",\n      \"pmids\": [\"28039148\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"hucMSC exosome-derived GPX1 protein is delivered to recipient hepatocytes and is required for the antioxidant and hepatoprotective effects of these exosomes; knockdown of GPX1 in donor hucMSCs abrogates the antioxidant and anti-apoptotic capacity of the exosomes both in vitro and in vivo.\",\n      \"method\": \"GPX1 knockdown in hucMSCs; exosome isolation and administration in CCl4 liver injury mouse model; measurement of oxidative stress markers, apoptosis, and liver function in vitro and in vivo\",\n      \"journal\": \"Molecular therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function in donor cells with in vitro and in vivo phenotypic readouts, single lab\",\n      \"pmids\": [\"28089078\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PER1 physically interacts with GPX1 in the cytoplasm and enhances GPX1 activity, thereby improving mitochondrial oxidative phosphorylation efficiency. Per1 deficiency impairs daily mitochondrial dynamics and deregulates cellular GPx-related ROS fluctuations in peripheral organs.\",\n      \"method\": \"Co-immunoprecipitation (PER1/GPX1 interaction); Per1 knockout mice; oxygen consumption rhythm measurement; GPx activity assay; mitochondrial function assays\",\n      \"journal\": \"Redox biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP for physical interaction plus knockout phenotype with functional enzymatic readout, single lab\",\n      \"pmids\": [\"32896721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CCL5 signaling increases GPX1 expression and reduces intracellular ROS in neurons; CCL5 knockout mice after mild TBI show reduced GPX1 activity, increased ROS, and impaired hippocampal memory recovery that can be rescued by intranasal recombinant CCL5 or N-acetylcysteine.\",\n      \"method\": \"CCL5 knockout mice with weight-drop TBI model; behavioral testing (Novel object recognition, Barnes Maze); NADPH oxidase activity; GPX1 activity assay; GPX1 overexpression in SHSY5Y cells; NAC and recombinant CCL5 rescue\",\n      \"journal\": \"Redox biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout plus pharmacological and recombinant protein rescue, multiple orthogonal readouts, single lab\",\n      \"pmids\": [\"34315111\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The splicing factor NONO, in association with PSPC1, binds a consensus motif in the intron of GPX1 pre-mRNA and promotes its correct splicing. NONO knockdown causes GPX1 intron retention, reducing functional GPX1 protein, impairing redox homeostasis and promoting apoptosis in glioblastoma cells.\",\n      \"method\": \"RNA sequencing of NONO-knockdown GBM cells; RIP-PCR and RNA pulldown to show NONO binding to GPX1 pre-mRNA intron; JC-1 staining and Seahorse assay for redox homeostasis; in vivo orthotopic xenograft model\",\n      \"journal\": \"Theranostics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct RNA pulldown identifying binding site, transcriptomic validation, in vivo model, single lab\",\n      \"pmids\": [\"35910786\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"DNMT2-mediated DNA methylation of the GPX1 promoter reduces GPX1 expression in AGE-exposed cardiomyocytes; selenium supplementation suppresses DNMT2 expression, reduces GPX1 promoter methylation, restores GPX1 expression/activity, and protects against AGE-induced cardiac dysfunction.\",\n      \"method\": \"Rat primary myocyte exposure to AGEs; bisulfite sequencing PCR of GPX1 promoter; DNMT inhibitor (AZA) and selenium supplementation; GPX1 activity and protein measurements; cardiac function evaluation in rat model\",\n      \"journal\": \"Oxidative medicine and cellular longevity\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct promoter methylation analysis with pharmacological rescue, in vitro and in vivo, single lab\",\n      \"pmids\": [\"35432721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"TRIM8 protein interacts with GPX1 and promotes GPX1 ubiquitination, leading to reduced GPX1 protein levels in cardiomyocytes; TRIM8 knockdown partially alleviates I/R-induced cardiomyocyte injury, and GPX1 knockdown abolishes the cardioprotective effect of salvianolic acid B.\",\n      \"method\": \"Co-IP of TRIM8 and GPX1; ubiquitination assay; TRIM8 knockdown/overexpression in AC16 cardiomyocytes; GPX1 knockdown rescue experiment; in vivo rat I/R model\",\n      \"journal\": \"Pharmaceutical biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, ubiquitination assay, epistasis experiment with knockdown, single lab\",\n      \"pmids\": [\"35968584\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"HIF-1α binds directly to the GPX1 promoter under hypoxic conditions to increase GPX1 expression, enabling glioblastoma cells to detoxify excess H2O2 caused by hypoxia. GPX1 depletion causes H2O2 overload and apoptosis in glioblastoma cells, and hypoxia also increases exosomal GPX1 that protects adjacent cells from H2O2 or radiation-induced apoptosis.\",\n      \"method\": \"HIF-1α ChIP on GPX1 promoter; GPX1 knockdown in glioblastoma cells; H2O2 measurement; apoptosis assay; exosome isolation and functional assays; glioblastoma xenograft model\",\n      \"journal\": \"Redox biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct ChIP demonstrating HIF-1α binding to GPX1 promoter, loss-of-function with mechanistic readout, in vivo xenograft, multiple orthogonal methods\",\n      \"pmids\": [\"37572455\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"GPX1 deficiency increases H2O2 levels that activate NF-κB p65, which upregulates renal angiotensin II type 1 receptor (AT1R) expression, causing sodium retention and hypertension in selenium-deficient rats. Ebselen (GPX1 mimetic), GPX1 silencing + NF-κB inhibitor (PDTC) experiments confirmed the GPx1/H2O2/NF-κB/AT1R pathway.\",\n      \"method\": \"Selenium-deficient rat model; GPx1 silencing in renal proximal tubule cells; NF-κB inhibitor PDTC; ebselen treatment; AT1R expression and Na+-K+-ATPase activity measurements; nuclear translocation of NF-κB p65\",\n      \"journal\": \"Free radical biology & medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pathway established by multiple pharmacological and genetic loss-of-function interventions in cells and in vivo, single lab\",\n      \"pmids\": [\"36868433\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GPX1 undergoes S-palmitoylation at cysteine residues 76 and 113; PPT1 (palmitoyl-protein thioesterase 1) mediates GPX1 depalmitoylation and reduces GPX1 protein stability. Inhibiting GPX1 palmitoylation (via PPT1 expression or non-palmitoylated mutant) enhances neovascular angiogenesis, while enhancing palmitoylation (PPT1 inhibition with DC661) suppresses retinal angiogenesis in an oxygen-induced retinopathy model.\",\n      \"method\": \"Palmitoylation site mapping at Cys-76 and Cys-113 by mutagenesis; PPT1 knockout and overexpression; non-palmitoylated Gpx1 mutant expression; oxygen-induced retinopathy mouse model; angiogenesis assays\",\n      \"journal\": \"Redox biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — site-directed mutagenesis identifying palmitoylation sites, genetic and pharmacological manipulation, in vivo disease model, multiple approaches in single study\",\n      \"pmids\": [\"39423458\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GPX1 is a selenocysteine-containing peroxidase that reduces H2O2 and lipid peroxides using glutathione as cofactor; it is encoded by a single gene that produces both cytosolic and mitochondrial isoforms, is translationally regulated by selenium availability (via SECIS-mediated UGA read-through), mTOR, and homocysteine, is transcriptionally controlled by TFAP2C, RORα, and HIF-1α, and is post-translationally regulated by O-GlcNAcylation (which activates it and promotes binding to c-Abl/Arg kinases), ubiquitination (promoted by the CUEDC2–TRIM33 and TRIM8 axes), promoter DNA methylation (by DNMT2/DNMT3a/b), and S-palmitoylation at Cys-76 and Cys-113 (modulated by PPT1); functionally, GPX1 protects against acute oxidative stress, ischemia-reperfusion injury, neurodegeneration, retinopathy, and colitis, regulates gap junction integrity in the lens, modulates the Bax/Bcl-2 apoptotic ratio, influences chondrogenic differentiation through redox balance, and controls angiogenesis via palmitoylation-dependent stability.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"GPX1 is a selenocysteine-containing glutathione peroxidase that detoxifies hydrogen peroxide and lipid hydroperoxides, serving as a central defense against acute oxidative stress in vivo [#0, #1]. A single Gpx1 gene encodes both the cytosolic and mitochondrial enzyme, and its loss eliminates detectable GPX activity in both compartments [#0]. Genetic ablation renders mice hypersensitive to the oxidant paraquat and sensitizes neurons to H2O2-induced death [#1], and GPX1-dependent peroxide removal is required for fibroblast proliferation and survival, where its loss provokes Cip1 elevation, NF-\\u03baB activation, and a senescence-like state [#4]. Across multiple tissues GPX1 is protective: it limits noise-induced cochlear damage [#2], maintains lens gap junction coupling through connexin 46/50 levels and ion homeostasis [#7], constrains pancreatic islet hydroperoxide accumulation and p53 phosphorylation [#9], and restrains retinal neovascularization in oxygen-induced retinopathy [#12]; in the colon it acts redundantly with GPX2, since only the GPX1/GPX2 double knockout develops spontaneous ileocolitis [#3]. GPX1 modulates apoptotic balance by lowering the Bax/Bcl-2 ratio [#6], and in selenium deficiency its loss elevates H2O2 to activate an NF-\\u03baB\\u2013AT1R axis driving renal sodium retention and hypertension [#24]. The enzyme is controlled at many levels: translation depends on selenocysteine UGA read-through that is impaired by homocysteine and suppressed by mTOR [#5, #14]; transcription is driven by TFAP2C, ROR\\u03b1, and hypoxic HIF-1\\u03b1 [#10, #13, #23]; pre-mRNA splicing requires NONO/PSPC1 [#20]; promoter activity is silenced by DNMT2-mediated CpG methylation [#10, #21]; and protein abundance is set by CUEDC2\\u2013TRIM33 and TRIM8 ubiquitin-mediated degradation as well as PPT1-regulated S-palmitoylation at Cys-76 and Cys-113 [#15, #22, #25]. Post-translationally, O-GlcNAcylation activates GPX1 and promotes its binding to c-Abl and Arg kinases [#8].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Resolved whether the cytosolic and mitochondrial glutathione peroxidases derive from one gene, establishing the genetic identity of GPX1.\",\n      \"evidence\": \"Subcellular fractionation and enzyme activity assay in Gpx1 knockout vs wild-type mouse liver\",\n      \"pmids\": [\"9126277\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not address differential targeting mechanism to mitochondria vs cytosol\", \"Single tissue (liver) examined\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Demonstrated that GPX1 is physiologically required to survive acute oxidant challenge, moving it from a biochemical activity to an in vivo protective enzyme.\",\n      \"evidence\": \"Paraquat lethality in Gpx1 knockout mice and H2O2 sensitivity of knockout cortical neurons\",\n      \"pmids\": [\"9712879\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not define which downstream targets of peroxide damage are protected\", \"Tissue-specific contributions not dissected\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Revealed functional redundancy between GPX1 and GPX2 in the gut, explaining why single GPX1 loss is often phenotypically silent in some tissues.\",\n      \"evidence\": \"Spontaneous ileocolitis with elevated myeloperoxidase and lipid hydroperoxides only in Gpx1/Gpx2 double knockout mice\",\n      \"pmids\": [\"11518697\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contribution of each isoform not quantified\", \"Mechanism linking peroxide accumulation to inflammation not detailed\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Established that GPX1 abundance is controlled at the level of selenocysteine UGA read-through, identifying homocysteine as a translational inhibitor independent of mRNA.\",\n      \"evidence\": \"UGA-luciferase SECIS reporter and folate-antagonist manipulation of homocysteine with activity/protein/mRNA readouts\",\n      \"pmids\": [\"15734734\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular step in selenocysteine machinery targeted by homocysteine not pinpointed\", \"In vivo relevance to disease states not tested here\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Connected GPX1 to apoptotic regulation by showing it lowers the pro-apoptotic Bax/Bcl-2 ratio.\",\n      \"evidence\": \"GPX1 cDNA overexpression in ECV304 endothelial cells with Bax/Bcl-2/p53 RT-PCR and Western blot\",\n      \"pmids\": [\"16132718\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Overexpression-only; loss-of-function not tested\", \"Mechanism linking peroxide removal to Bax transcription unknown\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Extended GPX1 function beyond classical antioxidant defense to maintaining lens gap junction coupling and ion homeostasis.\",\n      \"evidence\": \"Whole-lens impedance, ion imaging, and quantitative Western blot for Cx46/Cx50 in Gpx1 knockout lenses\",\n      \"pmids\": [\"19067024\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether connexin loss is direct or oxidative-damage-mediated unresolved\", \"Single-tissue specialization\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Identified a post-translational activating modification, showing O-GlcNAcylation activates GPX1 and couples it to c-Abl/Arg kinase signaling under hyperglycemia.\",\n      \"evidence\": \"O-GlcNAc IP/site mapping, Co-IP with c-Abl and Arg, and in vivo NTZ-induced activation in mouse liver\",\n      \"pmids\": [\"19944066\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of c-Abl/Arg binding not defined\", \"Co-IP without reciprocal structural validation of the modification site\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Distinguished H2O2- from superoxide-dependent control of pancreatic function, placing GPX1 specifically upstream of islet p53 activation and beta-cell mass.\",\n      \"evidence\": \"Islet hydroperoxide/superoxide measurement and p53 phosphorylation in GPX1 vs SOD1 knockout mice\",\n      \"pmids\": [\"20586612\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking H2O2 to p53 phosphorylation not resolved\", \"Single lab\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identified TFAP2C as a direct transcriptional activator of GPX1 and showed promoter CpG methylation silences GPX1 by blocking TFAP2C binding.\",\n      \"evidence\": \"ChIP-seq, TFAP2C knockdown, methylation analysis, and 5'-aza-dC demethylation in breast cancer cells\",\n      \"pmids\": [\"22964634\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether TFAP2C regulation operates outside breast cancer not tested\", \"Methylation-writing enzyme not identified here\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showed ZNF143 upregulates GPX1 activity and the selenocysteine synthesis pathway to support survival of respiration-defective cells.\",\n      \"evidence\": \"ZNF143/GPX1 knockdown, activity assays, and SepSecS expression in mitochondrial respiratory-defective cells\",\n      \"pmids\": [\"23152058\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct ZNF143 promoter binding to GPX1 not demonstrated\", \"Effect may be indirect via selenocysteine supply\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Defined additional layers of GPX1 control: ROR\\u03b1 as a transcriptional inducer and mTOR as a translational suppressor.\",\n      \"evidence\": \"ROR\\u03b1 overexpression/agonist in hepatocytes with promoter element mapping; rapamycin protein/mRNA dissociation in CML cells\",\n      \"pmids\": [\"24597775\", \"24691473\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"mTOR effect on selenocysteine machinery inferred, not mapped to a step\", \"ROR\\u03b1 element function not validated by mutation\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Reconstituted a ubiquitin-degradation pathway for GPX1, showing CUEDC2 drives TRIM33-mediated degradation that limits cardiac ROS scavenging.\",\n      \"evidence\": \"Cuedc2 knockout mice, Co-IP of CUEDC2-TRIM33-GPX1, ubiquitination assay, and in vivo I/R infarct measurement\",\n      \"pmids\": [\"27286733\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Ubiquitination site on GPX1 not mapped\", \"Whether TRIM33 directly ubiquitinates GPX1 vs scaffolds another E3 unresolved\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showed GPX1-dependent reductive balance, rather than ROS removal alone, is required for chondrogenic differentiation.\",\n      \"evidence\": \"shRNA knockdown in ATDC5 cells with GSH/GSSG measurement and diamide-versus-NAC rescue\",\n      \"pmids\": [\"28039148\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular targets of reductive stress in chondrogenesis unknown\", \"Single cell-line model\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrated GPX1 can act non-cell-autonomously, being delivered via exosomes to confer antioxidant and hepatoprotective effects on recipient cells.\",\n      \"evidence\": \"GPX1 knockdown in donor hucMSCs and exosome administration in CCl4 liver injury model\",\n      \"pmids\": [\"28089078\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of GPX1 loading into exosomes not defined\", \"Uptake/activity in recipient cells not quantified at enzyme level\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked GPX1 to circadian and mitochondrial physiology via a direct interaction with the clock protein PER1 that enhances its activity.\",\n      \"evidence\": \"Co-IP of PER1-GPX1, Per1 knockout mice, and oxygen-consumption rhythm/GPx activity assays\",\n      \"pmids\": [\"32896721\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How PER1 binding mechanistically enhances GPX1 activity unknown\", \"Single Co-IP without reciprocal mapping of interaction interface\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Placed GPX1 downstream of CCL5 signaling in neuronal ROS control relevant to traumatic brain injury recovery.\",\n      \"evidence\": \"CCL5 knockout TBI mice with GPX1 activity, behavioral testing, and recombinant CCL5/NAC rescue\",\n      \"pmids\": [\"34315111\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signaling steps linking CCL5 receptor to GPX1 expression not mapped\", \"Whether CCL5 acts transcriptionally on GPX1 untested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified pre-mRNA splicing as a control point, with NONO/PSPC1 binding a GPX1 intron motif to ensure correct splicing and functional protein.\",\n      \"evidence\": \"RIP-PCR/RNA pulldown of NONO on GPX1 pre-mRNA and intron-retention readout in NONO-knockdown glioblastoma cells\",\n      \"pmids\": [\"35910786\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct PSPC1 contribution not separated from NONO\", \"Generality of splicing dependence beyond glioblastoma untested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Added DNMT2-mediated promoter methylation and TRIM8-mediated ubiquitination as repressive controls on GPX1 in cardiomyocytes, and showed selenium reverses the methylation arm.\",\n      \"evidence\": \"Bisulfite sequencing and selenium/AZA rescue (DNMT2); Co-IP, ubiquitination assay, and I/R epistasis (TRIM8)\",\n      \"pmids\": [\"35432721\", \"35968584\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"TRIM8 ubiquitination site on GPX1 not mapped\", \"Whether DNMT2 acts directly on the GPX1 promoter or via intermediaries unresolved\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Established hypoxic induction of GPX1 by HIF-1\\u03b1 as a survival mechanism allowing tumor cells to detoxify hypoxia-driven H2O2, with exosomal GPX1 protecting neighboring cells.\",\n      \"evidence\": \"HIF-1\\u03b1 ChIP on GPX1 promoter, GPX1 knockdown with H2O2/apoptosis readouts, and glioblastoma xenografts\",\n      \"pmids\": [\"37572455\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the same axis operates in non-malignant hypoxic tissue not tested\", \"Mechanism of GPX1 exosomal sorting not defined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined a GPX1/H2O2/NF-\\u03baB/AT1R pathway linking selenium-dependent GPX1 loss to renal sodium handling and hypertension.\",\n      \"evidence\": \"Selenium-deficient rats, GPX1 silencing, NF-\\u03baB inhibitor and ebselen interventions with AT1R/Na+-K+-ATPase readouts\",\n      \"pmids\": [\"36868433\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular link between H2O2 and p65 activation not specified\", \"Single rodent model\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified S-palmitoylation at Cys-76 and Cys-113 as a stability-regulating modification, with PPT1 depalmitoylation destabilizing GPX1 and modulating angiogenesis.\",\n      \"evidence\": \"Palmitoylation site mutagenesis, PPT1 knockout/overexpression and DC661 inhibition in an oxygen-induced retinopathy model\",\n      \"pmids\": [\"39423458\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Palmitoyl-transferase adding the modification not identified\", \"How palmitoylation alters GPX1 stability mechanistically unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the many transcriptional, translational, splicing, and post-translational controls of GPX1 are integrated to set enzyme dosage in a given cell type, and which are dominant in human disease, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified quantitative model of GPX1 regulation across regulators\", \"Structural basis of GPX1 modification sites and partner binding not defined\", \"Most disease links rest on single-lab rodent or cell models\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016491\", \"supporting_discovery_ids\": [0, 1, 9]},\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [0, 5]},\n      {\"term_id\": \"GO:0016209\", \"supporting_discovery_ids\": [1, 4, 17]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 18]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 18]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [1, 4, 23]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [10, 13, 23]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [5, 15, 22, 25]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"c-Abl\", \"Arg\", \"TRIM33\", \"CUEDC2\", \"TRIM8\", \"PER1\", \"NONO\", \"PPT1\"],\n    \"other_free_text\": []\n  }\n}\n```","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":7,"faith_total":7,"faith_pct":100.0}}