{"gene":"SEPHS1","run_date":"2026-06-10T07:46:30","timeline":{"discoveries":[{"year":2017,"finding":"SEPHS1 forms oligomers with SEPHS2, SEPSECS, and SECp43 in mammalian cells; the SEPHS1–SEPHS2 interaction was confirmed by co-immunoprecipitation, placing SEPHS1 within the selenocysteine biosynthesis protein complex.","method":"Bioluminescence resonance energy transfer (BRET) assay in mammalian cells; co-immunoprecipitation","journal":"Biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus orthogonal BRET assay in a single lab","pmids":["28414460"],"is_preprint":false},{"year":2022,"finding":"SEPHS1 lacks selenophosphate synthesis activity (unlike its paralog SEPHS2) due to loss of the catalytic Sec/Cys residue, but retains ATPase activity producing ADP and inorganic phosphate, as inferred from its three-dimensional structure and phylogenetic analysis.","method":"Structural modeling (3D structure analysis) and phylogenetic analysis; ATPase activity inference from structural data","journal":"Archives of biochemistry and biophysics","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — structural and phylogenetic analysis with functional inference; no in vitro reconstitution reported in the abstract","pmids":["36202216"],"is_preprint":false},{"year":2021,"finding":"SEPHS1 deficiency in mouse endothelial (2H11) cells causes accumulation of superoxide and lipid peroxide and reduction of nitric oxide, mediated by induction of xanthine oxidase and NADPH oxidase activity and decreased SOD1/SOD3 expression, leading to G2/M cell cycle arrest, DNA damage (γH2AX foci), and inhibition of angiogenic tube formation.","method":"CRISPR/Cas9 knockout in cultured mouse 2H11 endothelial cells; ROS/superoxide assays; enzyme activity assays (xanthine oxidase, NADPH oxidase); flow cytometry for cell cycle; γH2AX immunofluorescence; tube formation assay","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular phenotype and multiple orthogonal assays in a single lab","pmids":["34769076"],"is_preprint":false},{"year":2021,"finding":"SEPHS1 knockout mice die by E11.5; deficiency progressively alters retinoic acid signaling, coagulation system, Wnt signaling (E6.5), prolactin signaling (E7.5), and insulin-like growth hormone signaling (E8.5), with gradual ROS accumulation leading to apoptosis and DNA damage detectable at E9.5.","method":"Systemic Sephs1 knockout mice; bioinformatics pathway analysis; morphological examination; apoptosis and DNA damage markers","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo KO with pathway verification, single lab, partially bioinformatics-driven with experimental confirmation","pmids":["34769078"],"is_preprint":false},{"year":2021,"finding":"SEPHS1 positively regulates SMAD2/3/4 protein expression in HCC cells; SEPHS1 knockdown decreases SMAD2/3/4 and mesenchymal markers (snail, slug, N-cadherin) and reduces TGF-β-stimulated cell migration and invasion; SMAD3 knockdown abrogates SEPHS1 overexpression-driven invasion, placing SEPHS1 upstream of TGF-β/SMAD signaling.","method":"siRNA knockdown and overexpression in HCC cell lines; Western blotting; transwell migration/invasion assay; epistasis via double knockdown (SEPHS1 OE + SMAD3 KD)","journal":"Experimental hematology & oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with defined phenotypic readout and multiple markers, single lab","pmids":["33622411"],"is_preprint":false},{"year":2019,"finding":"SEPHS1 is required for reprogramming efficiency in human pluripotent stem cells; knockdown reduces single-cell survival without altering core pluripotency gene expression, and triggers altered ROS pathway and apoptosis gene expression, indicating SEPHS1 regulates selenium-mediated redox signaling for hESC survival.","method":"siRNA knockdown in hESCs; reprogramming efficiency assay; clonogenicity assay; transcriptome analysis; ROS pathway analysis","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — KD with defined proliferation/survival phenotype and transcriptome, single lab, single method set","pmids":["31607477"],"is_preprint":false},{"year":2021,"finding":"SEPHS1 is dispensable for mouse ESC pluripotency and proliferation but is indispensable for differentiation into the three germ layers and for cardiac lineage specification; Sephs1 KO embryoid bodies show no beating and lack cardiac and contraction markers.","method":"CRISPR/Cas9 KO in mouse ESCs; gastruloid aggregation assay; RNA-seq; embryoid body beating assay; marker gene expression","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with multiple orthogonal readouts (RNA-seq, functional EB assay), single lab","pmids":["34974300"],"is_preprint":false},{"year":2024,"finding":"De novo missense variants at SEPHS1 residue Trp352 decrease overall thermal stability of the enzyme (local structural changes in C-terminal region), whereas variants at solvent-exposed Arg371 do not affect stability but may modulate direct protein-protein interactions; both classes of variants enhance cell proliferation by modulating ROS homeostasis in neuronal SH-SY5Y cells.","method":"Structural modeling; thermal stability biochemical assays; cell proliferation assays; ROS measurement in SH-SY5Y cells; mRNA expression of stress-related selenoproteins","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 1–2 / Moderate — biochemical thermal stability assays plus structural modeling plus cell-based functional assays, single study","pmids":["38531365"],"is_preprint":false},{"year":2023,"finding":"SEPHS1 delays nucleus pulposus cell senescence by reducing ROS production; SEPHS1 deficiency activates the Hippo-YAP/TAZ signaling pathway, and both SEPHS1 overexpression and Hippo-YAP/TAZ inhibition alleviate intervertebral disc degeneration in vivo; selenium deficiency and SEPHS1 loss synergistically aggravate disc degeneration.","method":"In vitro IL-1β-induced NPC senescence model; in vivo rat needle-puncture IVDD model; overexpression constructs; Hippo inhibitor treatment; ROS assays","journal":"American journal of physiology. Cell physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro and in vivo models with pathway epistasis (Hippo inhibitor rescue), single lab","pmids":["38105759"],"is_preprint":false},{"year":2025,"finding":"SEPHS1 knockdown in melanoma cells enhances CD8+ T cell recruitment and effector function, upregulates CXCL9/10 chemokines, and improves anti-PD-1 immunotherapy efficacy, establishing that SEPHS1 promotes immune evasion by suppressing chemokine expression and limiting CD8+ T cell infiltration.","method":"Gene knockdown in melanoma cells; T cell co-culture; flow cytometry; transcriptomic profiling; in vivo tumor models with anti-PD-1 treatment","journal":"Cancer immunology, immunotherapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro and in vivo KD with multiple orthogonal functional readouts, single lab","pmids":["41441975"],"is_preprint":false}],"current_model":"SEPHS1 is a catalytically inactive (with respect to selenophosphate synthesis) paralog of SEPHS2 that retains ATPase activity, participates in the selenocysteine biosynthesis complex via direct interactions with SEPHS2, SEPSECS, and SECp43, and functions primarily as a regulator of cellular redox homeostasis: its deficiency causes superoxide/ROS accumulation through dysregulation of xanthine oxidase, NADPH oxidase, and SOD enzymes, leading to DNA damage, apoptosis, cell cycle arrest, and pleiotropic developmental defects including embryonic lethality; it also positively regulates TGF-β/SMAD signaling, suppresses Hippo-YAP/TAZ activation, and modulates tumor immune evasion by limiting CD8+ T cell-recruiting chemokines."},"narrative":{"mechanistic_narrative":"SEPHS1 is a paralog of the selenophosphate synthetase SEPHS2 that has lost the catalytic Sec/Cys residue required for selenophosphate synthesis but retains ATPase activity yielding ADP and inorganic phosphate, and it physically associates with SEPHS2, SEPSECS, and SECp43 within the selenocysteine biosynthesis complex [PMID:28414460, PMID:36202216]. Functionally, its dominant role across cell types is the maintenance of redox homeostasis: loss of SEPHS1 drives superoxide and lipid peroxide accumulation through induction of xanthine oxidase and NADPH oxidase and downregulation of SOD1/SOD3, producing DNA damage, G2/M arrest, and impaired angiogenesis [PMID:34769076]. This redox control underlies pleiotropic developmental requirements — Sephs1-null mice die by E11.5 with progressive ROS-driven apoptosis and disrupted retinoic acid, Wnt, prolactin, and IGF signaling [PMID:34769078], and SEPHS1 is dispensable for ESC pluripotency yet indispensable for germ-layer and cardiac differentiation [PMID:34974300] and for survival during human pluripotent cell reprogramming [PMID:31607477]. Through ROS modulation SEPHS1 also intersects multiple signaling axes: it positively regulates SMAD2/3/4 levels to promote TGF-β-driven migration and invasion in hepatocellular carcinoma [PMID:33622411], suppresses Hippo-YAP/TAZ activation to delay nucleus pulposus senescence and disc degeneration [PMID:38105759], and limits CXCL9/10 chemokine expression to restrain CD8+ T cell infiltration and promote tumor immune evasion [PMID:41441975]. De novo missense variants at Trp352 (destabilizing) and Arg371 (interaction-modulating) enhance neuronal cell proliferation via altered ROS homeostasis, linking SEPHS1 to a human neurodevelopmental disorder [PMID:38531365].","teleology":[{"year":2017,"claim":"Established that SEPHS1 is a physical member of the selenocysteine biosynthesis machinery rather than an isolated enzyme, situating it among SEPHS2, SEPSECS, and SECp43.","evidence":"BRET assay and reciprocal co-immunoprecipitation in mammalian cells","pmids":["28414460"],"confidence":"Medium","gaps":["Stoichiometry and architecture of the complex not resolved","Functional consequence of each interaction not tested","Single-lab interaction data"]},{"year":2021,"claim":"Defined a concrete molecular mechanism for SEPHS1 deficiency, showing redox imbalance via specific oxidase induction and SOD loss drives DNA damage and cell cycle arrest.","evidence":"CRISPR/Cas9 knockout in mouse 2H11 endothelial cells with ROS, enzyme activity, cell cycle, γH2AX, and tube formation assays","pmids":["34769076"],"confidence":"Medium","gaps":["Mechanism linking SEPHS1 loss to oxidase induction unknown","Endothelial-specific vs general phenotype not separated","No direct enzymatic substrate identified"]},{"year":2021,"claim":"Demonstrated that the redox role of SEPHS1 is essential in vivo, with loss causing embryonic lethality preceded by staged disruption of multiple developmental signaling pathways.","evidence":"Systemic Sephs1 knockout mice with morphology, apoptosis/DNA damage markers, and bioinformatic pathway analysis","pmids":["34769078"],"confidence":"Medium","gaps":["Causal ordering of pathway changes is partly bioinformatic","Tissue of primary failure not pinpointed","Direct molecular targets not identified"]},{"year":2021,"claim":"Placed SEPHS1 upstream of TGF-β/SMAD signaling, connecting it to EMT and cancer cell invasion.","evidence":"siRNA knockdown, overexpression, and SEPHS1-OE/SMAD3-KD epistasis with migration/invasion assays in HCC cell lines","pmids":["33622411"],"confidence":"Medium","gaps":["How SEPHS1 regulates SMAD protein levels mechanistically unknown","Whether effect is ROS-dependent not tested","Single cancer type"]},{"year":2019,"claim":"Showed SEPHS1 supports stem cell survival during reprogramming through redox signaling rather than by controlling core pluripotency genes.","evidence":"siRNA knockdown in hESCs with reprogramming/clonogenicity assays, transcriptome and ROS pathway analysis","pmids":["31607477"],"confidence":"Medium","gaps":["Knockdown not knockout","Direct redox effector not identified","Single method set"]},{"year":2021,"claim":"Distinguished SEPHS1 requirement in differentiation from pluripotency, identifying a specific block in germ-layer and cardiac lineage specification.","evidence":"CRISPR/Cas9 KO mouse ESCs with gastruloid aggregation, RNA-seq, embryoid body beating, and marker assays","pmids":["34974300"],"confidence":"Medium","gaps":["Molecular basis of differentiation block not defined","Link to ROS in this context not established","Other lineages less characterized"]},{"year":2023,"claim":"Linked SEPHS1 redox control to suppression of Hippo-YAP/TAZ signaling and to a senescence/degeneration disease phenotype.","evidence":"IL-1β NPC senescence model and rat needle-puncture IVDD model with overexpression, Hippo inhibitor rescue, and ROS assays","pmids":["38105759"],"confidence":"Medium","gaps":["Mechanism connecting SEPHS1/ROS to Hippo activation unknown","Direct vs indirect YAP/TAZ regulation unresolved","Single tissue model"]},{"year":2024,"claim":"Connected SEPHS1 to a human neurodevelopmental disorder via de novo missense variants and showed two distinct biophysical mechanisms (destabilization vs interaction modulation) converge on ROS-driven proliferation.","evidence":"Structural modeling, thermal stability assays, and ROS/proliferation assays in SH-SY5Y cells","pmids":["38531365"],"confidence":"Medium","gaps":["Specific protein interactions altered by Arg371 not identified","Patient phenotype-to-cellular mechanism link incomplete","Single study"]},{"year":2025,"claim":"Identified SEPHS1 as a tumor-intrinsic driver of immune evasion that suppresses CD8+ T cell-recruiting chemokines, with knockdown enhancing anti-PD-1 efficacy.","evidence":"Knockdown in melanoma cells with T cell co-culture, flow cytometry, transcriptomics, and in vivo anti-PD-1 tumor models","pmids":["41441975"],"confidence":"Medium","gaps":["Pathway linking SEPHS1 to CXCL9/10 suppression undefined","Whether ROS mediates chemokine suppression untested","Single tumor type"]},{"year":null,"claim":"How SEPHS1 ATPase activity and complex membership mechanistically connect to its broad redox-regulatory and signaling functions remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No in vitro reconstitution of SEPHS1 ATPase function and its biological role","No direct substrate or effector linking ATPase activity to ROS control","Unifying mechanism across TGF-β, Hippo, and immune phenotypes not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[1]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[1]}],"localization":[],"pathway":[{"term_id":"R-HSA-8953897","term_label":"Cellular responses to stimuli","supporting_discovery_ids":[2,5]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[3,6]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,8]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[9]}],"complexes":["selenocysteine biosynthesis complex"],"partners":["SEPHS2","SEPSECS","SECP43"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P49903","full_name":"Zincore component SEPHS1","aliases":["Selenide, water dikinase 1","Selenium donor protein 1","Selenophosphate synthase 1"],"length_aa":392,"mass_kda":42.9,"function":"Core component of the zincore complex, a heterotetramer that acts as a molecular 'grip' to stabilize transcription factors at DNA-binding sites across the genome, thereby controlling gene expression (PubMed:40608935). The zincore complex binds specifically to zinc finger transcription factors, such as ZFP91, ZNF652, ZNF526 and PRDM15, and stabilizes them onto their cognate DNA motif (PubMed:40608935). Within the complex, SEPHS1, recognizes and binds the backbone of zinc fingers of transcription factors in a sequence-independent manner via its arginine clamp, enhancing their DNA-binding stability (PubMed:40608935). Plays an essential role in redox homeostasis (PubMed:31607477). May also be involved in selenocysteine biosynthesis by catalyzing formation of selenophosphate from selenide and ATP (PubMed:7665581). Its role in selenocysteine biosynthesis is however unclear and several studies suggest that it does not act as a selenophosphate synthase in vivo or plays an non-essential role (PubMed:15534230). Required for cardiac differentiation (By similarity)","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/P49903/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SEPHS1","classification":"Not Classified","n_dependent_lines":220,"n_total_lines":1208,"dependency_fraction":0.18211920529801323},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/SEPHS1","total_profiled":1310},"omim":[{"mim_id":"621325","title":"VERVERI-BRADY SYNDROME 2; VERBRAS2","url":"https://www.omim.org/entry/621325"},{"mim_id":"619597","title":"tRNA SELENOCYSTEINE 1-ASSOCIATED PROTEIN 1; TRNAU1AP","url":"https://www.omim.org/entry/619597"},{"mim_id":"619289","title":"ZINC FINGER PROTEIN 91, ATYPICAL E3 UBIQUITIN LIGASE; ZFP91","url":"https://www.omim.org/entry/619289"},{"mim_id":"617982","title":"VERVERI-BRADY SYNDROME 1; VERBRAS1","url":"https://www.omim.org/entry/617982"},{"mim_id":"617387","title":"GLUTAMINE-RICH PROTEIN 1; QRICH1","url":"https://www.omim.org/entry/617387"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Nucleoplasm","reliability":"Uncertain"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/SEPHS1"},"hgnc":{"alias_symbol":["SPS","SPS1"],"prev_symbol":[]},"alphafold":{"accession":"P49903","domains":[{"cath_id":"3.30.1330.10","chopping":"17-24_51-179","consensus_level":"high","plddt":92.8039,"start":17,"end":179},{"cath_id":"3.90.650.10","chopping":"194-377","consensus_level":"high","plddt":95.6812,"start":194,"end":377}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P49903","model_url":"https://alphafold.ebi.ac.uk/files/AF-P49903-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P49903-F1-predicted_aligned_error_v6.png","plddt_mean":89.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SEPHS1","jax_strain_url":"https://www.jax.org/strain/search?query=SEPHS1"},"sequence":{"accession":"P49903","fasta_url":"https://rest.uniprot.org/uniprotkb/P49903.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P49903/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P49903"}},"corpus_meta":[{"pmid":"33622411","id":"PMC_33622411","title":"SEPHS1 promotes SMAD2/3/4 expression and hepatocellular carcinoma cells invasion.","date":"2021","source":"Experimental hematology & oncology","url":"https://pubmed.ncbi.nlm.nih.gov/33622411","citation_count":26,"is_preprint":false},{"pmid":"28414460","id":"PMC_28414460","title":"Analysis of Novel Interactions between Components of the Selenocysteine Biosynthesis Pathway, SEPHS1, SEPHS2, SEPSECS, and SECp43.","date":"2017","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/28414460","citation_count":18,"is_preprint":false},{"pmid":"36202216","id":"PMC_36202216","title":"SEPHS1: Its evolution, function and roles in development and diseases.","date":"2022","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/36202216","citation_count":11,"is_preprint":false},{"pmid":"34769078","id":"PMC_34769078","title":"Identification of Signaling Pathways for Early Embryonic Lethality and Developmental Retardation in Sephs1 Mice.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/34769078","citation_count":11,"is_preprint":false},{"pmid":"34769076","id":"PMC_34769076","title":"Constitutive Oxidative Stress by SEPHS1 Deficiency Induces Endothelial Cell Dysfunction.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/34769076","citation_count":10,"is_preprint":false},{"pmid":"38105759","id":"PMC_38105759","title":"SEPHS1 attenuates intervertebral disc degeneration by delaying nucleus pulposus cell senescence through the Hippo-Yap/Taz pathway.","date":"2023","source":"American journal of physiology. Cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/38105759","citation_count":9,"is_preprint":false},{"pmid":"31607477","id":"PMC_31607477","title":"The role of selenium-mediated redox signaling by selenophosphate synthetase 1 (SEPHS1) in hESCs.","date":"2019","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/31607477","citation_count":6,"is_preprint":false},{"pmid":"34974300","id":"PMC_34974300","title":"SEPHS1 is dispensable for pluripotency maintenance but indispensable for cardiac differentiation in mouse embryonic stem cells.","date":"2021","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/34974300","citation_count":5,"is_preprint":false},{"pmid":"38531365","id":"PMC_38531365","title":"De novo missense variants in exon 9 of SEPHS1 cause a neurodevelopmental condition with developmental delay, poor growth, hypotonia, and dysmorphic features.","date":"2024","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/38531365","citation_count":4,"is_preprint":false},{"pmid":"38960024","id":"PMC_38960024","title":"SEPHS1 Gene: A new master key for neurodevelopmental disorders.","date":"2024","source":"Clinica chimica acta; international journal of clinical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/38960024","citation_count":2,"is_preprint":false},{"pmid":"41441975","id":"PMC_41441975","title":"Dissecting the role of SEPHS1 in shaping an immunosuppressive microenvironment to promote tumor progression.","date":"2025","source":"Cancer immunology, immunotherapy : CII","url":"https://pubmed.ncbi.nlm.nih.gov/41441975","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7738,"output_tokens":2577,"usd":0.030935,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9893,"output_tokens":3279,"usd":0.06572,"stage2_stop_reason":"end_turn"},"total_usd":0.096655,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"SEPHS1 forms oligomers with SEPHS2, SEPSECS, and SECp43 in mammalian cells; the SEPHS1–SEPHS2 interaction was confirmed by co-immunoprecipitation, placing SEPHS1 within the selenocysteine biosynthesis protein complex.\",\n      \"method\": \"Bioluminescence resonance energy transfer (BRET) assay in mammalian cells; co-immunoprecipitation\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus orthogonal BRET assay in a single lab\",\n      \"pmids\": [\"28414460\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"SEPHS1 lacks selenophosphate synthesis activity (unlike its paralog SEPHS2) due to loss of the catalytic Sec/Cys residue, but retains ATPase activity producing ADP and inorganic phosphate, as inferred from its three-dimensional structure and phylogenetic analysis.\",\n      \"method\": \"Structural modeling (3D structure analysis) and phylogenetic analysis; ATPase activity inference from structural data\",\n      \"journal\": \"Archives of biochemistry and biophysics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — structural and phylogenetic analysis with functional inference; no in vitro reconstitution reported in the abstract\",\n      \"pmids\": [\"36202216\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"SEPHS1 deficiency in mouse endothelial (2H11) cells causes accumulation of superoxide and lipid peroxide and reduction of nitric oxide, mediated by induction of xanthine oxidase and NADPH oxidase activity and decreased SOD1/SOD3 expression, leading to G2/M cell cycle arrest, DNA damage (γH2AX foci), and inhibition of angiogenic tube formation.\",\n      \"method\": \"CRISPR/Cas9 knockout in cultured mouse 2H11 endothelial cells; ROS/superoxide assays; enzyme activity assays (xanthine oxidase, NADPH oxidase); flow cytometry for cell cycle; γH2AX immunofluorescence; tube formation assay\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular phenotype and multiple orthogonal assays in a single lab\",\n      \"pmids\": [\"34769076\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"SEPHS1 knockout mice die by E11.5; deficiency progressively alters retinoic acid signaling, coagulation system, Wnt signaling (E6.5), prolactin signaling (E7.5), and insulin-like growth hormone signaling (E8.5), with gradual ROS accumulation leading to apoptosis and DNA damage detectable at E9.5.\",\n      \"method\": \"Systemic Sephs1 knockout mice; bioinformatics pathway analysis; morphological examination; apoptosis and DNA damage markers\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo KO with pathway verification, single lab, partially bioinformatics-driven with experimental confirmation\",\n      \"pmids\": [\"34769078\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"SEPHS1 positively regulates SMAD2/3/4 protein expression in HCC cells; SEPHS1 knockdown decreases SMAD2/3/4 and mesenchymal markers (snail, slug, N-cadherin) and reduces TGF-β-stimulated cell migration and invasion; SMAD3 knockdown abrogates SEPHS1 overexpression-driven invasion, placing SEPHS1 upstream of TGF-β/SMAD signaling.\",\n      \"method\": \"siRNA knockdown and overexpression in HCC cell lines; Western blotting; transwell migration/invasion assay; epistasis via double knockdown (SEPHS1 OE + SMAD3 KD)\",\n      \"journal\": \"Experimental hematology & oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with defined phenotypic readout and multiple markers, single lab\",\n      \"pmids\": [\"33622411\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SEPHS1 is required for reprogramming efficiency in human pluripotent stem cells; knockdown reduces single-cell survival without altering core pluripotency gene expression, and triggers altered ROS pathway and apoptosis gene expression, indicating SEPHS1 regulates selenium-mediated redox signaling for hESC survival.\",\n      \"method\": \"siRNA knockdown in hESCs; reprogramming efficiency assay; clonogenicity assay; transcriptome analysis; ROS pathway analysis\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — KD with defined proliferation/survival phenotype and transcriptome, single lab, single method set\",\n      \"pmids\": [\"31607477\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"SEPHS1 is dispensable for mouse ESC pluripotency and proliferation but is indispensable for differentiation into the three germ layers and for cardiac lineage specification; Sephs1 KO embryoid bodies show no beating and lack cardiac and contraction markers.\",\n      \"method\": \"CRISPR/Cas9 KO in mouse ESCs; gastruloid aggregation assay; RNA-seq; embryoid body beating assay; marker gene expression\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with multiple orthogonal readouts (RNA-seq, functional EB assay), single lab\",\n      \"pmids\": [\"34974300\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"De novo missense variants at SEPHS1 residue Trp352 decrease overall thermal stability of the enzyme (local structural changes in C-terminal region), whereas variants at solvent-exposed Arg371 do not affect stability but may modulate direct protein-protein interactions; both classes of variants enhance cell proliferation by modulating ROS homeostasis in neuronal SH-SY5Y cells.\",\n      \"method\": \"Structural modeling; thermal stability biochemical assays; cell proliferation assays; ROS measurement in SH-SY5Y cells; mRNA expression of stress-related selenoproteins\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — biochemical thermal stability assays plus structural modeling plus cell-based functional assays, single study\",\n      \"pmids\": [\"38531365\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SEPHS1 delays nucleus pulposus cell senescence by reducing ROS production; SEPHS1 deficiency activates the Hippo-YAP/TAZ signaling pathway, and both SEPHS1 overexpression and Hippo-YAP/TAZ inhibition alleviate intervertebral disc degeneration in vivo; selenium deficiency and SEPHS1 loss synergistically aggravate disc degeneration.\",\n      \"method\": \"In vitro IL-1β-induced NPC senescence model; in vivo rat needle-puncture IVDD model; overexpression constructs; Hippo inhibitor treatment; ROS assays\",\n      \"journal\": \"American journal of physiology. Cell physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro and in vivo models with pathway epistasis (Hippo inhibitor rescue), single lab\",\n      \"pmids\": [\"38105759\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SEPHS1 knockdown in melanoma cells enhances CD8+ T cell recruitment and effector function, upregulates CXCL9/10 chemokines, and improves anti-PD-1 immunotherapy efficacy, establishing that SEPHS1 promotes immune evasion by suppressing chemokine expression and limiting CD8+ T cell infiltration.\",\n      \"method\": \"Gene knockdown in melanoma cells; T cell co-culture; flow cytometry; transcriptomic profiling; in vivo tumor models with anti-PD-1 treatment\",\n      \"journal\": \"Cancer immunology, immunotherapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro and in vivo KD with multiple orthogonal functional readouts, single lab\",\n      \"pmids\": [\"41441975\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SEPHS1 is a catalytically inactive (with respect to selenophosphate synthesis) paralog of SEPHS2 that retains ATPase activity, participates in the selenocysteine biosynthesis complex via direct interactions with SEPHS2, SEPSECS, and SECp43, and functions primarily as a regulator of cellular redox homeostasis: its deficiency causes superoxide/ROS accumulation through dysregulation of xanthine oxidase, NADPH oxidase, and SOD enzymes, leading to DNA damage, apoptosis, cell cycle arrest, and pleiotropic developmental defects including embryonic lethality; it also positively regulates TGF-β/SMAD signaling, suppresses Hippo-YAP/TAZ activation, and modulates tumor immune evasion by limiting CD8+ T cell-recruiting chemokines.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SEPHS1 is a paralog of the selenophosphate synthetase SEPHS2 that has lost the catalytic Sec/Cys residue required for selenophosphate synthesis but retains ATPase activity yielding ADP and inorganic phosphate, and it physically associates with SEPHS2, SEPSECS, and SECp43 within the selenocysteine biosynthesis complex [#0, #1]. Functionally, its dominant role across cell types is the maintenance of redox homeostasis: loss of SEPHS1 drives superoxide and lipid peroxide accumulation through induction of xanthine oxidase and NADPH oxidase and downregulation of SOD1/SOD3, producing DNA damage, G2/M arrest, and impaired angiogenesis [#2]. This redox control underlies pleiotropic developmental requirements — Sephs1-null mice die by E11.5 with progressive ROS-driven apoptosis and disrupted retinoic acid, Wnt, prolactin, and IGF signaling [#3], and SEPHS1 is dispensable for ESC pluripotency yet indispensable for germ-layer and cardiac differentiation [#6] and for survival during human pluripotent cell reprogramming [#5]. Through ROS modulation SEPHS1 also intersects multiple signaling axes: it positively regulates SMAD2/3/4 levels to promote TGF-\\u03b2-driven migration and invasion in hepatocellular carcinoma [#4], suppresses Hippo-YAP/TAZ activation to delay nucleus pulposus senescence and disc degeneration [#8], and limits CXCL9/10 chemokine expression to restrain CD8+ T cell infiltration and promote tumor immune evasion [#9]. De novo missense variants at Trp352 (destabilizing) and Arg371 (interaction-modulating) enhance neuronal cell proliferation via altered ROS homeostasis, linking SEPHS1 to a human neurodevelopmental disorder [#7].\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Established that SEPHS1 is a physical member of the selenocysteine biosynthesis machinery rather than an isolated enzyme, situating it among SEPHS2, SEPSECS, and SECp43.\",\n      \"evidence\": \"BRET assay and reciprocal co-immunoprecipitation in mammalian cells\",\n      \"pmids\": [\"28414460\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Stoichiometry and architecture of the complex not resolved\", \"Functional consequence of each interaction not tested\", \"Single-lab interaction data\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined a concrete molecular mechanism for SEPHS1 deficiency, showing redox imbalance via specific oxidase induction and SOD loss drives DNA damage and cell cycle arrest.\",\n      \"evidence\": \"CRISPR/Cas9 knockout in mouse 2H11 endothelial cells with ROS, enzyme activity, cell cycle, \\u03b3H2AX, and tube formation assays\",\n      \"pmids\": [\"34769076\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking SEPHS1 loss to oxidase induction unknown\", \"Endothelial-specific vs general phenotype not separated\", \"No direct enzymatic substrate identified\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstrated that the redox role of SEPHS1 is essential in vivo, with loss causing embryonic lethality preceded by staged disruption of multiple developmental signaling pathways.\",\n      \"evidence\": \"Systemic Sephs1 knockout mice with morphology, apoptosis/DNA damage markers, and bioinformatic pathway analysis\",\n      \"pmids\": [\"34769078\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Causal ordering of pathway changes is partly bioinformatic\", \"Tissue of primary failure not pinpointed\", \"Direct molecular targets not identified\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Placed SEPHS1 upstream of TGF-\\u03b2/SMAD signaling, connecting it to EMT and cancer cell invasion.\",\n      \"evidence\": \"siRNA knockdown, overexpression, and SEPHS1-OE/SMAD3-KD epistasis with migration/invasion assays in HCC cell lines\",\n      \"pmids\": [\"33622411\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How SEPHS1 regulates SMAD protein levels mechanistically unknown\", \"Whether effect is ROS-dependent not tested\", \"Single cancer type\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Showed SEPHS1 supports stem cell survival during reprogramming through redox signaling rather than by controlling core pluripotency genes.\",\n      \"evidence\": \"siRNA knockdown in hESCs with reprogramming/clonogenicity assays, transcriptome and ROS pathway analysis\",\n      \"pmids\": [\"31607477\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Knockdown not knockout\", \"Direct redox effector not identified\", \"Single method set\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Distinguished SEPHS1 requirement in differentiation from pluripotency, identifying a specific block in germ-layer and cardiac lineage specification.\",\n      \"evidence\": \"CRISPR/Cas9 KO mouse ESCs with gastruloid aggregation, RNA-seq, embryoid body beating, and marker assays\",\n      \"pmids\": [\"34974300\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of differentiation block not defined\", \"Link to ROS in this context not established\", \"Other lineages less characterized\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Linked SEPHS1 redox control to suppression of Hippo-YAP/TAZ signaling and to a senescence/degeneration disease phenotype.\",\n      \"evidence\": \"IL-1\\u03b2 NPC senescence model and rat needle-puncture IVDD model with overexpression, Hippo inhibitor rescue, and ROS assays\",\n      \"pmids\": [\"38105759\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting SEPHS1/ROS to Hippo activation unknown\", \"Direct vs indirect YAP/TAZ regulation unresolved\", \"Single tissue model\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Connected SEPHS1 to a human neurodevelopmental disorder via de novo missense variants and showed two distinct biophysical mechanisms (destabilization vs interaction modulation) converge on ROS-driven proliferation.\",\n      \"evidence\": \"Structural modeling, thermal stability assays, and ROS/proliferation assays in SH-SY5Y cells\",\n      \"pmids\": [\"38531365\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific protein interactions altered by Arg371 not identified\", \"Patient phenotype-to-cellular mechanism link incomplete\", \"Single study\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified SEPHS1 as a tumor-intrinsic driver of immune evasion that suppresses CD8+ T cell-recruiting chemokines, with knockdown enhancing anti-PD-1 efficacy.\",\n      \"evidence\": \"Knockdown in melanoma cells with T cell co-culture, flow cytometry, transcriptomics, and in vivo anti-PD-1 tumor models\",\n      \"pmids\": [\"41441975\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Pathway linking SEPHS1 to CXCL9/10 suppression undefined\", \"Whether ROS mediates chemokine suppression untested\", \"Single tumor type\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SEPHS1 ATPase activity and complex membership mechanistically connect to its broad redox-regulatory and signaling functions remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No in vitro reconstitution of SEPHS1 ATPase function and its biological role\", \"No direct substrate or effector linking ATPase activity to ROS control\", \"Unifying mechanism across TGF-\\u03b2, Hippo, and immune phenotypes not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953897\", \"supporting_discovery_ids\": [2, 5]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [3, 6]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 8]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [9]}\n    ],\n    \"complexes\": [\"selenocysteine biosynthesis complex\"],\n    \"partners\": [\"SEPHS2\", \"SEPSECS\", \"SECp43\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":5,"faith_pct":80.0}}