{"gene":"NSDHL","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2000,"finding":"NSDHL encodes a 3β-hydroxysteroid dehydrogenase functioning in the cholesterol biosynthetic pathway; loss-of-function mutations in NSDHL cause CHILD syndrome, establishing its enzymatic role upstream of EBP (delta8-delta7 sterol isomerase) in post-squalene cholesterol biosynthesis.","method":"SSCA and genomic sequence analysis of NSDHL in CHILD syndrome patients; functional inference from pathway position relative to EBP","journal":"American journal of medical genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple independent patient mutations identified, pathway position established relative to EBP, replicated across labs in subsequent studies","pmids":["10710235"],"is_preprint":false},{"year":2003,"finding":"NSDHL protein localizes to ER membranes and on the surface of lipid droplets; trafficking through the Golgi is necessary for ER membrane localization. Mutant NSDHL alleles show altered subcellular distribution.","method":"Confocal microscopy of tagged wild-type and mutant murine Nsdhl proteins; Golgi disruption experiments","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization experiment with functional consequence (Golgi trafficking required for ER localization), single lab with orthogonal approaches","pmids":["14506130"],"is_preprint":false},{"year":2003,"finding":"Mouse NSDHL protein functionally complements lethality of erg26-deficient Saccharomyces cerevisiae, substantiating its role as a C-3 sterol dehydrogenase. Two striated (Str) alleles function as hypomorphs, while three bare patches (Bpa) and one Str allele provide no complementation.","method":"In vivo yeast functional complementation assay in erg26-deficient cells","journal":"Molecular genetics and metabolism","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vivo reconstitution of enzymatic function in yeast complementation assay, allele-specific functional hierarchy established, single lab","pmids":["14567972"],"is_preprint":false},{"year":2005,"finding":"Nsdhl-deficient male embryos die in midgestation (E10.5–13.5) with placental labyrinth thinning, fewer fetal vessels, and decreased proliferation of labyrinth trophoblast cells, indicating NSDHL is required for placental development.","method":"Histological and proliferation analysis of Nsdhl mutant mouse embryos at multiple embryonic stages","journal":"Molecular genetics and metabolism","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — defined cellular phenotype from loss-of-function with specific histological readout, multiple alleles examined","pmids":["15639195"],"is_preprint":false},{"year":2006,"finding":"Nsdhl deficiency impairs Hedgehog signaling in placental development: Ptch1-lacZ reporter expression is markedly decreased or absent in mutant Nsdhl(Bpa-8H) male placentas, and Indian hedgehog (Ihh)-expressing cells fail to migrate into allantoic mesoderm. Placental defects in heterozygous females are non-cell autonomous.","method":"Ptch1-lacZ transgenic reporter assay in Nsdhl mutant and wild-type placentas; X-linked lacZ transgene to assess cell autonomy","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic reporter assay with cell-autonomy dissection, multiple transgenic lines, pathway placement established","pmids":["17028112"],"is_preprint":false},{"year":2009,"finding":"NSDHL is expressed at highest levels in liver, dorsal root ganglia, CNS, retina, adrenal gland, and testis. NSDHL-deficient cells undergo negative selection over the life of the animal in liver and brain, with proportions dropping from ~50% at postnatal day 6 to ~20% by one year of age.","method":"Immunohistochemistry in wild-type and heterozygous Bpa(1H)/+ mice across embryonic and postnatal stages","journal":"Molecular genetics and metabolism","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization by IHC with functional consequence (negative selection), single lab, multiple time points","pmids":["19631568"],"is_preprint":false},{"year":2009,"finding":"Expression of Nsdhl specifically in trophoblast lineages (from the maternally inherited allele) has the largest effect on placental area in heterozygous embryos; maternal genotype has an independent smaller effect. Human NSDHL transgene rescues male lethality of the Bpa(1H) null allele.","method":"Transgenic rescue with human NSDHL; comparison of placental area at E10.5 using reciprocal cross design to dissect maternal vs. fetal membrane contributions","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 1 / Moderate — transgenic rescue experiment with quantitative phenotypic dissection, human NSDHL shown sufficient to restore function","pmids":["19880419"],"is_preprint":false},{"year":2010,"finding":"Hypomorphic NSDHL mutations (p.Lys232del and p.Arg367SerfsX33) cause CK syndrome with temperature-sensitive protein stability; these mutations complement Erg26-deficient yeast, confirming residual enzymatic activity. Cells and CSF from CKS patients have increased methyl sterol levels, implicating methyl sterol accumulation (not cholesterol deficiency) as pathogenic.","method":"Yeast complementation assay; temperature-sensitivity assays; sterol analysis of patient cells and CSF","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 1 / Strong — yeast complementation with biochemical sterol measurements, two independent patient families, multiple orthogonal methods","pmids":["21129721"],"is_preprint":false},{"year":2015,"finding":"Conditional ablation of Nsdhl in radial glia (GFAP-cre) causes defective SHH signaling, impairing cerebellar granule cell precursor proliferation; this defect is almost completely rescued by exogenous cholesterol supplementation in vitro, while methylsterol accumulation above the block is associated with increased cell death.","method":"Conditional Nsdhl knockout mice (Nsdhl(tm1.1Hrm)/GFAP-cre); in vitro granule cell precursor proliferation assay with cholesterol supplementation; sterol measurements","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 1 / Strong — conditional KO with defined phenotype, in vitro rescue with exogenous cholesterol, pathway placement in SHH signaling, multiple orthogonal methods","pmids":["25652406"],"is_preprint":false},{"year":2015,"finding":"FR171456 specifically inhibits NSDHL (human) and its yeast ortholog Erg26p; multiple ERG26 mutations confer resistance to FR171456 in growth and enzyme assays, and the compound significantly alters cholesterol pathway intermediate levels in human and yeast cells.","method":"Genome-wide yeast haploinsufficiency profiling; enzyme inhibition assays; resistance mutation mapping; sterol intermediate measurements in human cells","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — biochemical enzyme assay, resistance mutations, haploinsufficiency profiling, sterol measurements; multiple orthogonal methods","pmids":["26456460"],"is_preprint":false},{"year":2020,"finding":"X-ray crystal structures of human NSDHL reveal detailed coenzyme-binding site architecture and a unique conformational change upon coenzyme binding; structure-based virtual screening identified a novel inhibitor that suppresses EGFR activity in cancer cells.","method":"X-ray crystallography (two structures); structure-based virtual screening; biochemical inhibitor evaluation; cell-based EGFR activity assay","journal":"Cellular and molecular life sciences : CMLS","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structures with functional validation (inhibitor activity), multiple orthogonal methods in single study","pmids":["32140747"],"is_preprint":false},{"year":2020,"finding":"NSDHL knockdown attenuates adipogenesis in 3T3-L1 cells, associated with downregulation of the LXR-SREBP1 signaling pathway and reduced PPARγ expression.","method":"NSDHL knockdown in 3T3-L1 preadipocytes; qRT-PCR; lipid accumulation assay","journal":"Bioscience, biotechnology, and biochemistry","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single KD approach, pathway association without direct biochemical confirmation","pmids":["31985358"],"is_preprint":false},{"year":2021,"finding":"NSDHL activates TGFβ signaling by inhibiting endosomal degradation of TGFβR2 in triple-negative breast cancer cells; this function depends on NSDHL enzymatic activity (Y151X inactive mutant fails to rescue migration or TGFβR2 expression). Blocking upstream NSDHL metabolism with ketoconazole rescues TGFβR2 degradation.","method":"CRISPR screen in vivo; NSDHL knockdown/overexpression; inactive mutant (Y151X) rescue assay; ketoconazole treatment; TGFβR2 protein expression analysis","journal":"Breast cancer research and treatment","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — enzymatic activity requirement demonstrated by catalytic mutant, pathway placement via pharmacological rescue, single lab","pmids":["33864166"],"is_preprint":false},{"year":2023,"finding":"IFN-γ decreases NSDHL expression in HCC, which activates SREBP1 and promotes TGF-β1 production, reducing T cell cytotoxicity and enhancing Treg infiltration. Regorafenib reverses ICI resistance by restoring NSDHL/SREBP1/TGF-β1 axis.","method":"In vitro NSDHL knockdown/overexpression; SREBP1 and TGF-β1 expression assays; T cell co-culture; Treg infiltration analysis; regorafenib treatment","journal":"Biomedicine & pharmacotherapy","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pathway association from cell-based assays, single lab, mechanism not fully resolved biochemically","pmids":["36669362"],"is_preprint":false},{"year":2024,"finding":"NSDHL binds to STING and facilitates its degradation via ubiquitination, thereby inhibiting the cGAS-STING signaling pathway and reducing IFNβ synthesis in cholangiocarcinoma.","method":"Co-IP (NSDHL-STING interaction); overexpression/knockdown experiments; ubiquitination assay; IFNβ measurement","journal":"Heliyon","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP demonstrates binding, ubiquitination assay shows mechanism, single lab","pmids":["39290276"],"is_preprint":false},{"year":2024,"finding":"NSDHL knockdown in MCF-7 spheroids suppresses TGF-β1 and TGF-β3 secretion, reduces Smad2/3 phosphorylation, and decreases SOX2 expression, impairing breast cancer stem-like cell maintenance and tumor-initiating capacity.","method":"NSDHL knockdown in MCF-7 spheroids; RNA sequencing; BCSC phenotype assays (CD44/CD24, ALDH); orthotopic xenograft tumor initiation assay","journal":"BMC cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD with defined molecular and cellular phenotype, RNA-seq pathway identification, in vivo validation, single lab","pmids":["39516821"],"is_preprint":false},{"year":2026,"finding":"NSDHL knockdown in ovarian cancer cells triggers lipid peroxidation and ER stress-mediated apoptosis (not ferroptosis), with upregulation of ACSL4 and downregulation of ACSL3, reducing intracellular iron levels; NSDHL depletion suppresses tumor growth in xenografts.","method":"NSDHL knockdown; quantitative proteomic profiling; ROS measurement; ER stress marker analysis; ER-specific caspase activation assay; xenograft tumor model","journal":"Biology direct","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (proteomics, cell viability, ROS, caspase, xenograft), single lab","pmids":["41952197"],"is_preprint":false}],"current_model":"NSDHL is a 3β-hydroxysterol dehydrogenase/decarboxylase that removes C-4 methyl groups during post-squalene cholesterol biosynthesis, localizes to ER membranes and lipid droplet surfaces via Golgi-dependent trafficking, and beyond its metabolic role, regulates Hedgehog and TGFβ signaling pathways, controls STING stability via ubiquitination-mediated degradation, and modulates oxidative stress and ER stress responses, with loss-of-function causing CHILD syndrome and CK syndrome through a combination of cholesterol deficiency and toxic methyl sterol accumulation."},"narrative":{"mechanistic_narrative":"NSDHL is a 3β-hydroxysteroid dehydrogenase that catalyzes a C-4 demethylation step in post-squalene cholesterol biosynthesis, functioning upstream of the sterol isomerase EBP [PMID:10710235]; its enzymatic identity is established by complementation of erg26-deficient yeast, where allele-specific complementation defines a functional hierarchy among disease mutations [PMID:14567972, PMID:21129721]. The protein traffics through the Golgi to reach ER membranes and the surface of lipid droplets, and disease-associated mutants show altered subcellular distribution [PMID:14506130], with crystal structures defining its coenzyme-binding architecture and a conformational change upon coenzyme binding [PMID:32140747]. Loss-of-function mutations cause CHILD syndrome [PMID:10710235], while temperature-sensitive hypomorphic alleles retaining residual activity cause CK syndrome, in which methyl sterol accumulation rather than cholesterol deficiency is the pathogenic driver [PMID:21129721]. Through its control of cholesterol synthesis NSDHL is required for Hedgehog/SHH signaling: its deficiency abolishes Ptch1 reporter activity and Ihh cell migration in the placenta [PMID:17028112] and impairs SHH-dependent cerebellar granule precursor proliferation, a defect rescued by exogenous cholesterol while methylsterol accumulation drives cell death [PMID:25652406]. NSDHL is also required for placental labyrinth development and trophoblast proliferation, with human NSDHL sufficient to rescue murine null lethality [PMID:15639195, PMID:19880419]. In cancer contexts its enzymatic output feeds the LXR-SREBP1 lipogenic axis and activates TGFβ signaling by limiting endosomal degradation of TGFβR2, supporting cancer stem-like maintenance and tumor initiation [PMID:33864166, PMID:39516821], and NSDHL additionally binds STING to promote its ubiquitination-mediated degradation, dampening cGAS-STING-driven IFNβ production [PMID:39290276].","teleology":[{"year":2000,"claim":"Identified NSDHL as a cholesterol-biosynthetic enzyme and placed it as the genetic cause of CHILD syndrome, establishing both its molecular function and disease relevance.","evidence":"SSCA and genomic sequencing of NSDHL in CHILD syndrome patients with pathway inference relative to EBP","pmids":["10710235"],"confidence":"High","gaps":["Enzymatic activity inferred from pathway position, not directly reconstituted","Catalytic mechanism and substrate specificity not biochemically defined"]},{"year":2003,"claim":"Defined where the protein acts in the cell and that Golgi transit is required to reach the ER, linking trafficking to function.","evidence":"Confocal microscopy of tagged wild-type and mutant murine Nsdhl with Golgi disruption","pmids":["14506130"],"confidence":"Medium","gaps":["Targeting signals and trafficking machinery not identified","Single lab"]},{"year":2003,"claim":"Directly confirmed NSDHL as a C-3 sterol dehydrogenase by rescuing erg26-deficient yeast and ranked disease alleles by residual activity.","evidence":"In vivo yeast complementation assay in erg26-deficient cells with multiple Bpa/Str alleles","pmids":["14567972"],"confidence":"High","gaps":["Heterologous yeast system does not measure mammalian kinetics","Reaction product not directly characterized"]},{"year":2005,"claim":"Established that NSDHL is required for placental development, identifying a tissue-level consequence of enzyme loss.","evidence":"Histology and proliferation analysis of Nsdhl mutant mouse embryos across stages","pmids":["15639195"],"confidence":"Medium","gaps":["Molecular pathway linking sterol defect to trophoblast proliferation not yet defined"]},{"year":2006,"claim":"Connected NSDHL loss to impaired Hedgehog signaling, providing a mechanistic link between a metabolic enzyme and a developmental signaling pathway.","evidence":"Ptch1-lacZ reporter and X-linked lacZ cell-autonomy assays in mutant placentas","pmids":["17028112"],"confidence":"High","gaps":["Whether the Hh defect reflects cholesterol loss, sterol accumulation, or both not resolved here"]},{"year":2009,"claim":"Mapped expression and demonstrated negative selection of NSDHL-deficient cells in liver and brain, showing a cell-intrinsic fitness requirement.","evidence":"Immunohistochemistry across embryonic and postnatal stages in Bpa(1H)/+ mice","pmids":["19631568"],"confidence":"Medium","gaps":["Molecular basis of negative selection not defined"]},{"year":2009,"claim":"Showed the trophoblast lineage is the critical site of NSDHL action and that human NSDHL rescues murine null lethality, confirming functional conservation.","evidence":"Transgenic rescue with human NSDHL and reciprocal-cross placental area dissection","pmids":["19880419"],"confidence":"High","gaps":["Maternal-effect mechanism not mechanistically explained"]},{"year":2010,"claim":"Established that hypomorphic NSDHL alleles with residual activity cause CK syndrome and that methyl sterol accumulation, not cholesterol deficiency, is the pathogenic driver.","evidence":"Yeast complementation, temperature-sensitivity assays, and sterol analysis of patient cells and CSF","pmids":["21129721"],"confidence":"High","gaps":["Mechanism of methyl sterol toxicity not defined"]},{"year":2015,"claim":"Dissected the SHH cerebellar phenotype to show cholesterol deficiency drives the signaling defect while methylsterol accumulation drives cell death, separating two distinct consequences of enzyme loss.","evidence":"GFAP-cre conditional Nsdhl knockout with in vitro granule precursor proliferation rescue by cholesterol","pmids":["25652406"],"confidence":"High","gaps":["How cholesterol modulates SHH at the molecular level not resolved in this system"]},{"year":2015,"claim":"Provided a specific small-molecule (FR171456) and resistance-mutation map confirming NSDHL/Erg26 as a druggable enzyme with defined pathway output.","evidence":"Yeast haploinsufficiency profiling, enzyme inhibition assays, resistance mapping, and sterol measurements","pmids":["26456460"],"confidence":"High","gaps":["Inhibitor selectivity in mammalian tissues not extensively characterized"]},{"year":2020,"claim":"Solved NSDHL crystal structures, revealing coenzyme-binding architecture and enabling structure-based inhibitor discovery.","evidence":"X-ray crystallography of two structures with structure-based virtual screening and cell-based EGFR assays","pmids":["32140747"],"confidence":"High","gaps":["Substrate-bound structure not reported","Mechanistic link to EGFR activity not biochemically defined"]},{"year":2021,"claim":"Linked NSDHL enzymatic activity to TGFβ signaling by showing it limits endosomal degradation of TGFβR2 in breast cancer cells.","evidence":"In vivo CRISPR screen, catalytic mutant (Y151X) rescue, and ketoconazole pharmacological rescue of TGFβR2","pmids":["33864166"],"confidence":"Medium","gaps":["Sterol intermediate responsible for TGFβR2 stabilization not identified","Single lab"]},{"year":2024,"claim":"Identified a non-metabolic role in innate immunity, with NSDHL binding STING and promoting its ubiquitination-mediated degradation to suppress IFNβ.","evidence":"Co-IP, ubiquitination assay, and knockdown/overexpression with IFNβ measurement in cholangiocarcinoma","pmids":["39290276"],"confidence":"Medium","gaps":["Whether degradation depends on enzymatic activity or scaffolding not resolved","Reciprocal validation and E3 ligase not identified","Single lab Co-IP"]},{"year":2024,"claim":"Extended the TGFβ link to cancer stem-cell biology, showing NSDHL knockdown lowers TGFβ secretion, Smad2/3 phosphorylation, and SOX2 to impair tumor initiation.","evidence":"Knockdown in MCF-7 spheroids with RNA-seq, BCSC phenotyping, and orthotopic xenograft initiation assay","pmids":["39516821"],"confidence":"Medium","gaps":["Mechanism connecting sterol metabolism to TGFβ secretion not biochemically defined"]},{"year":2026,"claim":"Implicated NSDHL in redox and ER-stress homeostasis, with knockdown triggering lipid peroxidation and ER stress-mediated apoptosis in ovarian cancer.","evidence":"Knockdown with quantitative proteomics, ROS and ER stress markers, ER-specific caspase assay, and xenografts","pmids":["41952197"],"confidence":"Medium","gaps":["Distinction from ferroptosis depends on marker interpretation","Direct molecular trigger of ER stress not defined","Single lab"]},{"year":null,"claim":"How NSDHL's sterol-metabolic output is mechanistically transduced into its signaling roles (Hedgehog, TGFβ, STING/cGAS, ER stress) remains unresolved — whether through specific sterol intermediates, membrane composition, or moonlighting protein interactions.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No single sterol intermediate causally tied to a downstream signaling outcome","Catalysis-dependent vs. catalysis-independent contributions to STING regulation undefined","No structural or biochemical model for NSDHL-partner protein interactions"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016491","term_label":"oxidoreductase activity","supporting_discovery_ids":[0,2,7,9]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[1]},{"term_id":"GO:0005811","term_label":"lipid droplet","supporting_discovery_ids":[1]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,2,7,9]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,8,12]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[3,6]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[14]}],"complexes":[],"partners":["STING1","TGFBR2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q15738","full_name":"Sterol-4-alpha-carboxylate 3-dehydrogenase, decarboxylating","aliases":["Protein H105e3"],"length_aa":373,"mass_kda":41.9,"function":"Catalyzes the NAD(P)(+)-dependent oxidative decarboxylation of the C4 methyl groups of 4-alpha-carboxysterols in post-squalene cholesterol biosynthesis (By similarity). Also plays a role in the regulation of the endocytic trafficking of EGFR (By similarity)","subcellular_location":"Endoplasmic reticulum membrane; Lipid droplet","url":"https://www.uniprot.org/uniprotkb/Q15738/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NSDHL","classification":"Not Classified","n_dependent_lines":4,"n_total_lines":1208,"dependency_fraction":0.0033112582781456954},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000147383","cell_line_id":"CID000288","localizations":[{"compartment":"er","grade":3},{"compartment":"vesicles","grade":2}],"interactors":[{"gene":"CDS1","stoichiometry":0.2},{"gene":"CLTA","stoichiometry":0.2},{"gene":"COPA","stoichiometry":0.2},{"gene":"COPB2","stoichiometry":0.2},{"gene":"COPE","stoichiometry":0.2},{"gene":"FASN","stoichiometry":0.2},{"gene":"IDI1","stoichiometry":0.2},{"gene":"MVD","stoichiometry":0.2},{"gene":"POMT1","stoichiometry":0.2},{"gene":"HSD17B12","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000288","total_profiled":1310},"omim":[{"mim_id":"616834","title":"MICROCEPHALY, CONGENITAL CATARACT, AND PSORIASIFORM DERMATITIS; MCCPD","url":"https://www.omim.org/entry/616834"},{"mim_id":"308300","title":"INCONTINENTIA PIGMENTI; IP","url":"https://www.omim.org/entry/308300"},{"mim_id":"308050","title":"CONGENITAL HEMIDYSPLASIA WITH ICHTHYOSIFORM ERYTHRODERMA AND LIMB DEFECTS","url":"https://www.omim.org/entry/308050"},{"mim_id":"300831","title":"CK SYNDROME; CKS","url":"https://www.omim.org/entry/300831"},{"mim_id":"300275","title":"NAD(P)H STEROID DEHYDROGENASE-LIKE PROTEIN; NSDHL","url":"https://www.omim.org/entry/300275"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Endoplasmic reticulum","reliability":"Enhanced"},{"location":"Lipid droplets","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/NSDHL"},"hgnc":{"alias_symbol":["XAP104","H105e3","SDR31E1"],"prev_symbol":[]},"alphafold":{"accession":"Q15738","domains":[{"cath_id":"3.40.50.720","chopping":"29-368","consensus_level":"medium","plddt":93.1647,"start":29,"end":368}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q15738","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q15738-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q15738-F1-predicted_aligned_error_v6.png","plddt_mean":88.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NSDHL","jax_strain_url":"https://www.jax.org/strain/search?query=NSDHL"},"sequence":{"accession":"Q15738","fasta_url":"https://rest.uniprot.org/uniprotkb/Q15738.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q15738/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q15738"}},"corpus_meta":[{"pmid":"10710235","id":"PMC_10710235","title":"Mutations in the NSDHL gene, encoding a 3beta-hydroxysteroid dehydrogenase, cause CHILD syndrome.","date":"2000","source":"American journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10710235","citation_count":191,"is_preprint":false},{"pmid":"14506130","id":"PMC_14506130","title":"NSDHL, an enzyme involved in cholesterol biosynthesis, traffics through the Golgi and accumulates on ER membranes and on the surface of lipid droplets.","date":"2003","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/14506130","citation_count":84,"is_preprint":false},{"pmid":"21129721","id":"PMC_21129721","title":"Hypomorphic temperature-sensitive alleles of NSDHL cause CK syndrome.","date":"2010","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21129721","citation_count":44,"is_preprint":false},{"pmid":"11907515","id":"PMC_11907515","title":"A novel missense mutation of NSDHL in an unusual case of CHILD syndrome showing bilateral, almost symmetric involvement.","date":"2002","source":"Journal of the American Academy of Dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/11907515","citation_count":38,"is_preprint":false},{"pmid":"33864166","id":"PMC_33864166","title":"NSDHL promotes triple-negative breast cancer metastasis through the TGFβ signaling pathway and cholesterol biosynthesis.","date":"2021","source":"Breast cancer research and treatment","url":"https://pubmed.ncbi.nlm.nih.gov/33864166","citation_count":33,"is_preprint":false},{"pmid":"25652406","id":"PMC_25652406","title":"Analysis of hedgehog signaling in cerebellar granule cell precursors in a conditional Nsdhl allele demonstrates an essential role for cholesterol in postnatal CNS development.","date":"2015","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/25652406","citation_count":29,"is_preprint":false},{"pmid":"12966526","id":"PMC_12966526","title":"Left-sided CHILD syndrome caused by a nonsense mutation in the NSDHL gene.","date":"2003","source":"American journal of medical genetics. 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loss-of-function mutations in NSDHL cause CHILD syndrome, establishing its enzymatic role upstream of EBP (delta8-delta7 sterol isomerase) in post-squalene cholesterol biosynthesis.\",\n      \"method\": \"SSCA and genomic sequence analysis of NSDHL in CHILD syndrome patients; functional inference from pathway position relative to EBP\",\n      \"journal\": \"American journal of medical genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple independent patient mutations identified, pathway position established relative to EBP, replicated across labs in subsequent studies\",\n      \"pmids\": [\"10710235\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"NSDHL protein localizes to ER membranes and on the surface of lipid droplets; trafficking through the Golgi is necessary for ER membrane localization. Mutant NSDHL alleles show altered subcellular distribution.\",\n      \"method\": \"Confocal microscopy of tagged wild-type and mutant murine Nsdhl proteins; Golgi disruption experiments\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiment with functional consequence (Golgi trafficking required for ER localization), single lab with orthogonal approaches\",\n      \"pmids\": [\"14506130\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Mouse NSDHL protein functionally complements lethality of erg26-deficient Saccharomyces cerevisiae, substantiating its role as a C-3 sterol dehydrogenase. Two striated (Str) alleles function as hypomorphs, while three bare patches (Bpa) and one Str allele provide no complementation.\",\n      \"method\": \"In vivo yeast functional complementation assay in erg26-deficient cells\",\n      \"journal\": \"Molecular genetics and metabolism\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vivo reconstitution of enzymatic function in yeast complementation assay, allele-specific functional hierarchy established, single lab\",\n      \"pmids\": [\"14567972\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Nsdhl-deficient male embryos die in midgestation (E10.5–13.5) with placental labyrinth thinning, fewer fetal vessels, and decreased proliferation of labyrinth trophoblast cells, indicating NSDHL is required for placental development.\",\n      \"method\": \"Histological and proliferation analysis of Nsdhl mutant mouse embryos at multiple embryonic stages\",\n      \"journal\": \"Molecular genetics and metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — defined cellular phenotype from loss-of-function with specific histological readout, multiple alleles examined\",\n      \"pmids\": [\"15639195\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Nsdhl deficiency impairs Hedgehog signaling in placental development: Ptch1-lacZ reporter expression is markedly decreased or absent in mutant Nsdhl(Bpa-8H) male placentas, and Indian hedgehog (Ihh)-expressing cells fail to migrate into allantoic mesoderm. Placental defects in heterozygous females are non-cell autonomous.\",\n      \"method\": \"Ptch1-lacZ transgenic reporter assay in Nsdhl mutant and wild-type placentas; X-linked lacZ transgene to assess cell autonomy\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic reporter assay with cell-autonomy dissection, multiple transgenic lines, pathway placement established\",\n      \"pmids\": [\"17028112\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"NSDHL is expressed at highest levels in liver, dorsal root ganglia, CNS, retina, adrenal gland, and testis. NSDHL-deficient cells undergo negative selection over the life of the animal in liver and brain, with proportions dropping from ~50% at postnatal day 6 to ~20% by one year of age.\",\n      \"method\": \"Immunohistochemistry in wild-type and heterozygous Bpa(1H)/+ mice across embryonic and postnatal stages\",\n      \"journal\": \"Molecular genetics and metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization by IHC with functional consequence (negative selection), single lab, multiple time points\",\n      \"pmids\": [\"19631568\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Expression of Nsdhl specifically in trophoblast lineages (from the maternally inherited allele) has the largest effect on placental area in heterozygous embryos; maternal genotype has an independent smaller effect. Human NSDHL transgene rescues male lethality of the Bpa(1H) null allele.\",\n      \"method\": \"Transgenic rescue with human NSDHL; comparison of placental area at E10.5 using reciprocal cross design to dissect maternal vs. fetal membrane contributions\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — transgenic rescue experiment with quantitative phenotypic dissection, human NSDHL shown sufficient to restore function\",\n      \"pmids\": [\"19880419\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Hypomorphic NSDHL mutations (p.Lys232del and p.Arg367SerfsX33) cause CK syndrome with temperature-sensitive protein stability; these mutations complement Erg26-deficient yeast, confirming residual enzymatic activity. Cells and CSF from CKS patients have increased methyl sterol levels, implicating methyl sterol accumulation (not cholesterol deficiency) as pathogenic.\",\n      \"method\": \"Yeast complementation assay; temperature-sensitivity assays; sterol analysis of patient cells and CSF\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — yeast complementation with biochemical sterol measurements, two independent patient families, multiple orthogonal methods\",\n      \"pmids\": [\"21129721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Conditional ablation of Nsdhl in radial glia (GFAP-cre) causes defective SHH signaling, impairing cerebellar granule cell precursor proliferation; this defect is almost completely rescued by exogenous cholesterol supplementation in vitro, while methylsterol accumulation above the block is associated with increased cell death.\",\n      \"method\": \"Conditional Nsdhl knockout mice (Nsdhl(tm1.1Hrm)/GFAP-cre); in vitro granule cell precursor proliferation assay with cholesterol supplementation; sterol measurements\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — conditional KO with defined phenotype, in vitro rescue with exogenous cholesterol, pathway placement in SHH signaling, multiple orthogonal methods\",\n      \"pmids\": [\"25652406\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"FR171456 specifically inhibits NSDHL (human) and its yeast ortholog Erg26p; multiple ERG26 mutations confer resistance to FR171456 in growth and enzyme assays, and the compound significantly alters cholesterol pathway intermediate levels in human and yeast cells.\",\n      \"method\": \"Genome-wide yeast haploinsufficiency profiling; enzyme inhibition assays; resistance mutation mapping; sterol intermediate measurements in human cells\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — biochemical enzyme assay, resistance mutations, haploinsufficiency profiling, sterol measurements; multiple orthogonal methods\",\n      \"pmids\": [\"26456460\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"X-ray crystal structures of human NSDHL reveal detailed coenzyme-binding site architecture and a unique conformational change upon coenzyme binding; structure-based virtual screening identified a novel inhibitor that suppresses EGFR activity in cancer cells.\",\n      \"method\": \"X-ray crystallography (two structures); structure-based virtual screening; biochemical inhibitor evaluation; cell-based EGFR activity assay\",\n      \"journal\": \"Cellular and molecular life sciences : CMLS\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structures with functional validation (inhibitor activity), multiple orthogonal methods in single study\",\n      \"pmids\": [\"32140747\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"NSDHL knockdown attenuates adipogenesis in 3T3-L1 cells, associated with downregulation of the LXR-SREBP1 signaling pathway and reduced PPARγ expression.\",\n      \"method\": \"NSDHL knockdown in 3T3-L1 preadipocytes; qRT-PCR; lipid accumulation assay\",\n      \"journal\": \"Bioscience, biotechnology, and biochemistry\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single KD approach, pathway association without direct biochemical confirmation\",\n      \"pmids\": [\"31985358\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"NSDHL activates TGFβ signaling by inhibiting endosomal degradation of TGFβR2 in triple-negative breast cancer cells; this function depends on NSDHL enzymatic activity (Y151X inactive mutant fails to rescue migration or TGFβR2 expression). Blocking upstream NSDHL metabolism with ketoconazole rescues TGFβR2 degradation.\",\n      \"method\": \"CRISPR screen in vivo; NSDHL knockdown/overexpression; inactive mutant (Y151X) rescue assay; ketoconazole treatment; TGFβR2 protein expression analysis\",\n      \"journal\": \"Breast cancer research and treatment\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — enzymatic activity requirement demonstrated by catalytic mutant, pathway placement via pharmacological rescue, single lab\",\n      \"pmids\": [\"33864166\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"IFN-γ decreases NSDHL expression in HCC, which activates SREBP1 and promotes TGF-β1 production, reducing T cell cytotoxicity and enhancing Treg infiltration. Regorafenib reverses ICI resistance by restoring NSDHL/SREBP1/TGF-β1 axis.\",\n      \"method\": \"In vitro NSDHL knockdown/overexpression; SREBP1 and TGF-β1 expression assays; T cell co-culture; Treg infiltration analysis; regorafenib treatment\",\n      \"journal\": \"Biomedicine & pharmacotherapy\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pathway association from cell-based assays, single lab, mechanism not fully resolved biochemically\",\n      \"pmids\": [\"36669362\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NSDHL binds to STING and facilitates its degradation via ubiquitination, thereby inhibiting the cGAS-STING signaling pathway and reducing IFNβ synthesis in cholangiocarcinoma.\",\n      \"method\": \"Co-IP (NSDHL-STING interaction); overexpression/knockdown experiments; ubiquitination assay; IFNβ measurement\",\n      \"journal\": \"Heliyon\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP demonstrates binding, ubiquitination assay shows mechanism, single lab\",\n      \"pmids\": [\"39290276\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NSDHL knockdown in MCF-7 spheroids suppresses TGF-β1 and TGF-β3 secretion, reduces Smad2/3 phosphorylation, and decreases SOX2 expression, impairing breast cancer stem-like cell maintenance and tumor-initiating capacity.\",\n      \"method\": \"NSDHL knockdown in MCF-7 spheroids; RNA sequencing; BCSC phenotype assays (CD44/CD24, ALDH); orthotopic xenograft tumor initiation assay\",\n      \"journal\": \"BMC cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD with defined molecular and cellular phenotype, RNA-seq pathway identification, in vivo validation, single lab\",\n      \"pmids\": [\"39516821\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"NSDHL knockdown in ovarian cancer cells triggers lipid peroxidation and ER stress-mediated apoptosis (not ferroptosis), with upregulation of ACSL4 and downregulation of ACSL3, reducing intracellular iron levels; NSDHL depletion suppresses tumor growth in xenografts.\",\n      \"method\": \"NSDHL knockdown; quantitative proteomic profiling; ROS measurement; ER stress marker analysis; ER-specific caspase activation assay; xenograft tumor model\",\n      \"journal\": \"Biology direct\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (proteomics, cell viability, ROS, caspase, xenograft), single lab\",\n      \"pmids\": [\"41952197\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NSDHL is a 3β-hydroxysterol dehydrogenase/decarboxylase that removes C-4 methyl groups during post-squalene cholesterol biosynthesis, localizes to ER membranes and lipid droplet surfaces via Golgi-dependent trafficking, and beyond its metabolic role, regulates Hedgehog and TGFβ signaling pathways, controls STING stability via ubiquitination-mediated degradation, and modulates oxidative stress and ER stress responses, with loss-of-function causing CHILD syndrome and CK syndrome through a combination of cholesterol deficiency and toxic methyl sterol accumulation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NSDHL is a 3β-hydroxysteroid dehydrogenase that catalyzes a C-4 demethylation step in post-squalene cholesterol biosynthesis, functioning upstream of the sterol isomerase EBP [#0]; its enzymatic identity is established by complementation of erg26-deficient yeast, where allele-specific complementation defines a functional hierarchy among disease mutations [#2, #7]. The protein traffics through the Golgi to reach ER membranes and the surface of lipid droplets, and disease-associated mutants show altered subcellular distribution [#1], with crystal structures defining its coenzyme-binding architecture and a conformational change upon coenzyme binding [#10]. Loss-of-function mutations cause CHILD syndrome [#0], while temperature-sensitive hypomorphic alleles retaining residual activity cause CK syndrome, in which methyl sterol accumulation rather than cholesterol deficiency is the pathogenic driver [#7]. Through its control of cholesterol synthesis NSDHL is required for Hedgehog/SHH signaling: its deficiency abolishes Ptch1 reporter activity and Ihh cell migration in the placenta [#4] and impairs SHH-dependent cerebellar granule precursor proliferation, a defect rescued by exogenous cholesterol while methylsterol accumulation drives cell death [#8]. NSDHL is also required for placental labyrinth development and trophoblast proliferation, with human NSDHL sufficient to rescue murine null lethality [#3, #6]. In cancer contexts its enzymatic output feeds the LXR-SREBP1 lipogenic axis and activates TGFβ signaling by limiting endosomal degradation of TGFβR2, supporting cancer stem-like maintenance and tumor initiation [#12, #15], and NSDHL additionally binds STING to promote its ubiquitination-mediated degradation, dampening cGAS-STING-driven IFNβ production [#14].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Identified NSDHL as a cholesterol-biosynthetic enzyme and placed it as the genetic cause of CHILD syndrome, establishing both its molecular function and disease relevance.\",\n      \"evidence\": \"SSCA and genomic sequencing of NSDHL in CHILD syndrome patients with pathway inference relative to EBP\",\n      \"pmids\": [\"10710235\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Enzymatic activity inferred from pathway position, not directly reconstituted\", \"Catalytic mechanism and substrate specificity not biochemically defined\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Defined where the protein acts in the cell and that Golgi transit is required to reach the ER, linking trafficking to function.\",\n      \"evidence\": \"Confocal microscopy of tagged wild-type and mutant murine Nsdhl with Golgi disruption\",\n      \"pmids\": [\"14506130\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Targeting signals and trafficking machinery not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Directly confirmed NSDHL as a C-3 sterol dehydrogenase by rescuing erg26-deficient yeast and ranked disease alleles by residual activity.\",\n      \"evidence\": \"In vivo yeast complementation assay in erg26-deficient cells with multiple Bpa/Str alleles\",\n      \"pmids\": [\"14567972\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Heterologous yeast system does not measure mammalian kinetics\", \"Reaction product not directly characterized\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Established that NSDHL is required for placental development, identifying a tissue-level consequence of enzyme loss.\",\n      \"evidence\": \"Histology and proliferation analysis of Nsdhl mutant mouse embryos across stages\",\n      \"pmids\": [\"15639195\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular pathway linking sterol defect to trophoblast proliferation not yet defined\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Connected NSDHL loss to impaired Hedgehog signaling, providing a mechanistic link between a metabolic enzyme and a developmental signaling pathway.\",\n      \"evidence\": \"Ptch1-lacZ reporter and X-linked lacZ cell-autonomy assays in mutant placentas\",\n      \"pmids\": [\"17028112\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the Hh defect reflects cholesterol loss, sterol accumulation, or both not resolved here\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Mapped expression and demonstrated negative selection of NSDHL-deficient cells in liver and brain, showing a cell-intrinsic fitness requirement.\",\n      \"evidence\": \"Immunohistochemistry across embryonic and postnatal stages in Bpa(1H)/+ mice\",\n      \"pmids\": [\"19631568\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of negative selection not defined\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Showed the trophoblast lineage is the critical site of NSDHL action and that human NSDHL rescues murine null lethality, confirming functional conservation.\",\n      \"evidence\": \"Transgenic rescue with human NSDHL and reciprocal-cross placental area dissection\",\n      \"pmids\": [\"19880419\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Maternal-effect mechanism not mechanistically explained\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Established that hypomorphic NSDHL alleles with residual activity cause CK syndrome and that methyl sterol accumulation, not cholesterol deficiency, is the pathogenic driver.\",\n      \"evidence\": \"Yeast complementation, temperature-sensitivity assays, and sterol analysis of patient cells and CSF\",\n      \"pmids\": [\"21129721\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of methyl sterol toxicity not defined\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Dissected the SHH cerebellar phenotype to show cholesterol deficiency drives the signaling defect while methylsterol accumulation drives cell death, separating two distinct consequences of enzyme loss.\",\n      \"evidence\": \"GFAP-cre conditional Nsdhl knockout with in vitro granule precursor proliferation rescue by cholesterol\",\n      \"pmids\": [\"25652406\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How cholesterol modulates SHH at the molecular level not resolved in this system\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Provided a specific small-molecule (FR171456) and resistance-mutation map confirming NSDHL/Erg26 as a druggable enzyme with defined pathway output.\",\n      \"evidence\": \"Yeast haploinsufficiency profiling, enzyme inhibition assays, resistance mapping, and sterol measurements\",\n      \"pmids\": [\"26456460\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Inhibitor selectivity in mammalian tissues not extensively characterized\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Solved NSDHL crystal structures, revealing coenzyme-binding architecture and enabling structure-based inhibitor discovery.\",\n      \"evidence\": \"X-ray crystallography of two structures with structure-based virtual screening and cell-based EGFR assays\",\n      \"pmids\": [\"32140747\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Substrate-bound structure not reported\", \"Mechanistic link to EGFR activity not biochemically defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Linked NSDHL enzymatic activity to TGFβ signaling by showing it limits endosomal degradation of TGFβR2 in breast cancer cells.\",\n      \"evidence\": \"In vivo CRISPR screen, catalytic mutant (Y151X) rescue, and ketoconazole pharmacological rescue of TGFβR2\",\n      \"pmids\": [\"33864166\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Sterol intermediate responsible for TGFβR2 stabilization not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified a non-metabolic role in innate immunity, with NSDHL binding STING and promoting its ubiquitination-mediated degradation to suppress IFNβ.\",\n      \"evidence\": \"Co-IP, ubiquitination assay, and knockdown/overexpression with IFNβ measurement in cholangiocarcinoma\",\n      \"pmids\": [\"39290276\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether degradation depends on enzymatic activity or scaffolding not resolved\", \"Reciprocal validation and E3 ligase not identified\", \"Single lab Co-IP\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Extended the TGFβ link to cancer stem-cell biology, showing NSDHL knockdown lowers TGFβ secretion, Smad2/3 phosphorylation, and SOX2 to impair tumor initiation.\",\n      \"evidence\": \"Knockdown in MCF-7 spheroids with RNA-seq, BCSC phenotyping, and orthotopic xenograft initiation assay\",\n      \"pmids\": [\"39516821\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting sterol metabolism to TGFβ secretion not biochemically defined\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Implicated NSDHL in redox and ER-stress homeostasis, with knockdown triggering lipid peroxidation and ER stress-mediated apoptosis in ovarian cancer.\",\n      \"evidence\": \"Knockdown with quantitative proteomics, ROS and ER stress markers, ER-specific caspase assay, and xenografts\",\n      \"pmids\": [\"41952197\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Distinction from ferroptosis depends on marker interpretation\", \"Direct molecular trigger of ER stress not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NSDHL's sterol-metabolic output is mechanistically transduced into its signaling roles (Hedgehog, TGFβ, STING/cGAS, ER stress) remains unresolved — whether through specific sterol intermediates, membrane composition, or moonlighting protein interactions.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No single sterol intermediate causally tied to a downstream signaling outcome\", \"Catalysis-dependent vs. catalysis-independent contributions to STING regulation undefined\", \"No structural or biochemical model for NSDHL-partner protein interactions\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016491\", \"supporting_discovery_ids\": [0, 2, 7, 9]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005811\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 2, 7, 9]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 8, 12]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [3, 6]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [14]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"STING1\", \"TGFBR2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}