{"gene":"SULT2B1","run_date":"2026-06-10T10:51:54","timeline":{"discoveries":[{"year":1998,"finding":"SULT2B1 encodes two distinct hydroxysteroid sulfotransferase isoforms (SULT2B1a and SULT2B1b) from a single gene via alternative transcription initiation and alternative splicing at different 5' exons. Both isoforms catalyze sulfation of dehydroepiandrosterone but not 4-nitrophenol or 17β-estradiol.","method":"cDNA cloning, COS-1 cell expression, enzymatic activity assays, Northern blot, genomic mapping","journal":"Genomics","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct enzymatic reconstitution in mammalian cells with substrate specificity assays, cloning and gene structure fully characterized","pmids":["9799594"],"is_preprint":false},{"year":2002,"finding":"SULT2B1b (exon 1B) functions as a cholesterol sulfotransferase, while SULT2B1a (exon 1A) functions as a pregnenolone sulfotransferase. The unique N-terminal amino acids of SULT2B1b, specifically isoleucines at positions 21 and 23, are critical for cholesterol sulfation activity. Deletion of the 53 amino acid C-terminal extension does not affect catalytic activity of either isoform.","method":"Deletion analysis, site-directed mutagenesis, enzymatic activity assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution with mutagenesis and deletion analysis, multiple orthogonal methods, precise residues identified","pmids":["12145317"],"is_preprint":false},{"year":2001,"finding":"Both SULT2B1a and SULT2B1b specifically catalyze sulfonation of 3β-hydroxysteroids with high catalytic efficiency, and both also sulfonate dihydrotestosterone. Tissue expression is detected in placenta, ovary, uterus, and prostate.","method":"In vitro enzymatic activity assays, kinetic analysis, tissue expression analysis","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro enzymatic characterization in single study with substrate specificity profiling, no independent replication cited","pmids":["11594786"],"is_preprint":false},{"year":2003,"finding":"Mouse SULT2B1 isoforms have predilection for cholesterol sulfation over SULT2A1; SULT2B1a is most abundantly expressed in brain and spinal cord (pregnenolone sulfotransferase activity), while SULT2B1b is predominantly expressed in skin (cholesterol sulfotransferase activity). Both isoforms derive from a single gene via alternative exon I.","method":"cDNA cloning, gene structure analysis, real-time RT-PCR, enzymatic characterization","journal":"Endocrinology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — enzymatic characterization plus tissue localization via qPCR, replicated structure of alternative splicing from human gene","pmids":["12639899"],"is_preprint":false},{"year":2007,"finding":"Deletion of the proline-rich SULT2B1 C-terminus results in intracellular protein aggregate formation and accelerated degradation of the truncated protein, demonstrating that the C-terminal domain is required for protein stability. Nonsynonymous coding SNPs produce variant allozymes with 64–98% of wild-type enzymatic activity.","method":"Mammalian expression system, functional genomics, allozyme activity assays, protein stability assessment","journal":"The Journal of pharmacology and experimental therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — deletion construct in mammalian expression system with protein stability readout; multiple allozymes tested","pmids":["17496163"],"is_preprint":false},{"year":2013,"finding":"SULT2B1b shows nuclear localization in selected tissues, which appears related to serine phosphorylation of the carboxy-terminal peptide. Only SULT2B1b protein has been reliably detected in human tissues investigated.","method":"Tissue fractionation, protein localization studies, phosphorylation analysis (review with experimental basis cited)","journal":"Drug metabolism reviews","confidence":"Low","confidence_rationale":"Tier 3 / Weak — localization and phosphorylation claims reported in a review without detailed primary experimental methods described in the abstract","pmids":["24020383"],"is_preprint":false},{"year":2017,"finding":"Loss-of-function mutations in SULT2B1 cause autosomal-recessive congenital ichthyosis. SULT2B1-deficient keratinocytes in 3D organotypic cultures show absence of cholesterol sulfate and increased free cholesterol, indicating SULT2B1 is required for epidermal cholesterol sulfate synthesis. Loss of SULT2B1 leads to increased keratinocyte proliferation and thickened epithelial layers.","method":"Whole-exome sequencing, functional analysis of patient keratinocytes, 3D organotypic tissue culture, thin layer chromatography of cholesterol metabolites, RT-PCR, protein expression analysis","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct loss-of-function in patient-derived cells plus 3D model reconstitution with metabolite readout by TLC; multiple independent families and orthogonal methods","pmids":["28575648"],"is_preprint":false},{"year":2021,"finding":"Sult2b1 deficiency in mice exacerbates ischemic stroke outcomes; cholesterol sulfate produced by SULT2B1 attenuates pro-inflammatory macrophage polarization by regulating NADPH and ROS levels and activating AMPK-CREB signaling pathway. Peripheral monocyte-derived macrophages are the dominant cell type promoting pro-inflammatory status in Sult2b1-deficient mice after stroke.","method":"Sult2b1 knockout mice, transient MCAO model, bone marrow transplantation, immune cell depletion, adoptive monocyte transfer, CyTOF, primary BMDM assays","journal":"Theranostics","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal approaches (KO, bone marrow transplant, cell depletion, adoptive transfer) with mechanistic pathway identification (AMPK-CREB)","pmids":["34815805"],"is_preprint":false},{"year":2023,"finding":"Cholesterol sulfate synthesized by SULT2B1 in HCC tumor cells suppresses DOCK2 enzymatic activity in T cells, promoting effector CD8+ T-cell exhaustion. This constitutes a SULT2B1-CS-DOCK2 axis regulating tumor-infiltrating lymphocyte function.","method":"Quasi-targeted metabolomics, mass spectrometry, mass cytometry (CyTOF), flow cytometry, RNA sequencing, mouse HCC models, molecular docking simulation","journal":"Hepatology (Baltimore, Md.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — metabolomics plus functional assays in mouse models identify cholesterol sulfate as the mediating metabolite, but direct biochemical inhibition of DOCK2 by CS requires further validation","pmids":["36626623"],"is_preprint":false},{"year":2023,"finding":"Macrophage SULT2B1 promotes pathological choroidal neovascularization in AMD by supporting M2 macrophage activation. Sult2b1 deficiency activates LXR signaling and increases ABCA1/ABCG1-mediated cholesterol efflux from M2 macrophages, reducing M2 polarization. STS (sterol desulfonase, opposing enzyme) protects against CNV by activating LXR-ABCA1/G1 signaling.","method":"Sult2b1 knockout mice, in vivo CNV model, in vitro macrophage polarization assays, LXR inhibitor (GSK2033) treatment","journal":"Life science alliance","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO mice with defined phenotypic and molecular readout, LXR pathway mechanism validated by pharmacological inhibition","pmids":["37550000"],"is_preprint":false},{"year":2024,"finding":"SULT2B1 directly interacts with SCD1 (stearoyl-CoA desaturase 1) to facilitate lipid metabolism in colon cancer cells, and promotes metastasis. SMC1A transcriptionally upregulates SULT2B1 expression.","method":"Single-cell sequencing, proteomics, CC orthotopic mouse model, in vitro assays, co-immunoprecipitation (implied by 'directly interacted'), SULT2B1-KO","journal":"Clinical and translational medicine","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — protein-protein interaction with SCD1 and transcriptional regulation by SMC1A reported, but methods for interaction are not fully detailed in abstract","pmids":["38372484"],"is_preprint":false},{"year":2024,"finding":"ETV4 (from M2 macrophage-derived exosomes) transcriptionally activates SULT2B1 expression by binding to the SULT2B1 promoter, promoting HCC cell proliferation, glycolysis and stemness.","method":"Dual-luciferase reporter assay, chromatin immunoprecipitation (ChIP), exosome co-culture, xenograft mouse model","journal":"Liver international","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and luciferase reporter establish ETV4 as transcriptional activator of SULT2B1, single lab study","pmids":["39639836"],"is_preprint":false},{"year":2024,"finding":"SULT2B1 directly interacts with AKT and enhances AKT-mTORC1 signaling activity in colorectal cancer cells. SULT2B1 also binds PKM2 and regulates it at both transcriptional and protein degradation levels, promoting glycolysis and cell proliferation.","method":"Immunoprecipitation, GST pull-down assay, immunofluorescence, ChIP assay, mCherry-GFP-LC3 autophagy assay, small molecule agonist/antagonist validation","journal":"Journal of translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal pulldown (IP + GST) for AKT and PKM2 interactions, multiple orthogonal methods in single lab","pmids":["39623433"],"is_preprint":false},{"year":2024,"finding":"Suppression of SULT2B1 in macrophages reduces nuclear 25HC3S levels, elevates LXR expression, and increases transcription of LncRNA gga3-204. LncRNA gga3-204 binds SMAD4, facilitating its nuclear entry to regulate Smad7 transcription, suppressing NF-κB nuclear entry and attenuating macrophage inflammation in atherosclerosis.","method":"Sult2b1 knockdown in mouse AS model, nuclear fractionation, LncRNA expression analysis, in vivo and in vitro functional assays","journal":"Translational research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multi-step pathway established by KD experiments in vivo and in vitro with molecular readouts, single lab","pmids":["38286358"],"is_preprint":false},{"year":2025,"finding":"TGF-β1 induces SULT2B1 overexpression in cholangiocytes, which activates the Wnt/β-catenin/MMP7 pathway to promote epithelial-mesenchymal transition (EMT). Silencing SULT2B1 blocks Wnt/β-catenin/MMP7-mediated cholangiocyte EMT.","method":"In vitro TGF-β1 treatment of human intrahepatic bile duct epithelial cells, SULT2B1 silencing, pathway analysis by immunoblotting","journal":"Pediatric research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single cell-line model, pathway inferred from knockdown and pathway inhibitor experiments without direct biochemical mechanism","pmids":["41402642"],"is_preprint":false},{"year":2025,"finding":"SULT2B1-produced cholesterol sulfate (CS) acts as an endogenous DOCK2-inhibitory metabolite in the skin, suppressing immune cell migration and activation. Sult2b1 knockout in mice exacerbates imiquimod-induced psoriatic dermatitis with enhanced neutrophil recruitment; genetic deletion of DOCK2 or neutrophil depletion alleviates the worsened dermatitis in Sult2b1 KO mice, establishing epistasis between SULT2B1-CS and DOCK2-mediated Rac activation.","method":"Sult2b1 knockout mice, imiquimod psoriasis model, Dock2 genetic deletion, neutrophil-depleting antibody treatment, CS measurement, human keratinocyte cytokine stimulation assays","journal":"Frontiers in immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis (double KO rescue), pharmacological validation, multiple orthogonal methods establishing CS-DOCK2 mechanistic axis in vivo","pmids":["41181147"],"is_preprint":false},{"year":2019,"finding":"SULT2B1b allozymes with nonsynonymous SNPs show differential sulfating activities and altered kinetic parameters (substrate-binding affinity and catalytic activity) toward DHEA and pregnenolone compared to wild-type SULT2B1b.","method":"Expression of allozymes in heterologous system, kinetic analysis (Km, Vmax determination) toward DHEA and pregnenolone","journal":"Molecular and cellular endocrinology","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — rigorous kinetic characterization of allozymes but single lab with no independent replication","pmids":["31400397"],"is_preprint":false}],"current_model":"SULT2B1 is a cytosolic sulfotransferase encoded by a single gene that generates two isoforms (SULT2B1a and SULT2B1b) via alternative transcription initiation and splicing: SULT2B1b acts primarily as a cholesterol sulfotransferase (requiring N-terminal isoleucines at positions 21/23), while SULT2B1a preferentially sulfates pregnenolone; the cholesterol sulfate product regulates multiple downstream processes including epidermal barrier formation, macrophage polarization (via AMPK-CREB and LXR-ABCA1/G1 pathways), CD8+ T-cell exhaustion (by inhibiting DOCK2-Rac activity), and skin immune homeostasis, while SULT2B1 protein itself interacts with AKT and PKM2 to modulate glycolysis and cancer cell signaling."},"narrative":{"mechanistic_narrative":"SULT2B1 is a cytosolic hydroxysteroid sulfotransferase that catalyzes the sulfonation of 3β-hydroxysteroids, encoded by a single gene that produces two isoforms via alternative transcription initiation and 5'-exon splicing: SULT2B1b, which preferentially sulfates cholesterol, and SULT2B1a, which preferentially sulfates pregnenolone [PMID:9799594, PMID:12145317, PMID:12639899]. The distinct N-terminal sequence of SULT2B1b — specifically isoleucines at positions 21 and 23 — confers its cholesterol sulfotransferase activity, while a proline-rich C-terminal extension is dispensable for catalysis but required for protein stability [PMID:12145317, PMID:17496163]. The principal product, cholesterol sulfate, mediates most downstream physiology: SULT2B1 supplies epidermal cholesterol sulfate and restrains keratinocyte proliferation, and biallelic loss-of-function mutations cause autosomal-recessive congenital ichthyosis [PMID:28575648]. Cholesterol sulfate generated by SULT2B1 functions as an endogenous inhibitor of DOCK2-driven Rac activation, an axis that suppresses CD8+ T-cell exhaustion in hepatocellular carcinoma and limits neutrophil-driven psoriatic skin inflammation [PMID:36626623, PMID:41181147]. In macrophages, SULT2B1-dependent sterol sulfation tunes inflammatory polarization through AMPK-CREB signaling and through nuclear oxysterol/LXR-ABCA1/G1 control of cholesterol efflux, influencing ischemic stroke, choroidal neovascularization, and atherosclerosis [PMID:34815805, PMID:37550000, PMID:38286358]. Beyond its sterol-sulfating role, SULT2B1 protein physically engages metabolic and signaling effectors — AKT and PKM2 to drive mTORC1 signaling and glycolysis, and SCD1 to support lipid metabolism — promoting proliferation and metastasis in gastrointestinal cancers, where it is transcriptionally induced by ETV4, SMC1A, and TGF-β1 [PMID:38372484, PMID:39639836, PMID:39623433].","teleology":[{"year":1998,"claim":"Established that a single SULT2B1 gene generates two hydroxysteroid sulfotransferase isoforms with shared DHEA-sulfating but distinct substrate boundaries, defining the gene's basic architecture.","evidence":"cDNA cloning, COS-1 expression and enzymatic assays, Northern blot, genomic mapping","pmids":["9799594"],"confidence":"High","gaps":["Physiological substrate preferences of each isoform not yet resolved","Tissue-specific isoform deployment not yet mapped"]},{"year":2001,"claim":"Refined the catalytic profile, showing both isoforms efficiently sulfonate 3β-hydroxysteroids and dihydrotestosterone, with expression in reproductive tissues.","evidence":"In vitro kinetic assays and tissue expression analysis","pmids":["11594786"],"confidence":"Medium","gaps":["Single-study characterization without independent replication","In vivo relevance of DHT sulfation unestablished"]},{"year":2002,"claim":"Resolved the isoform functional dichotomy and its structural basis, attributing cholesterol sulfotransferase activity of SULT2B1b to N-terminal isoleucines 21/23 and showing the C-terminal extension is dispensable for catalysis.","evidence":"Deletion analysis, site-directed mutagenesis, enzymatic assays","pmids":["12145317"],"confidence":"High","gaps":["Structural mechanism by which Ile21/23 enable cholesterol binding not solved","Function of the C-terminal extension not yet defined"]},{"year":2003,"claim":"Confirmed the conserved isoform architecture in mouse and mapped tissue specialization — SULT2B1a in brain/spinal cord, SULT2B1b in skin — linking each isoform's activity to its dominant tissue.","evidence":"cDNA cloning, gene structure analysis, real-time RT-PCR, enzymatic characterization in mouse","pmids":["12639899"],"confidence":"Medium","gaps":["Functional consequence of brain pregnenolone sulfation not tested","Causal link of skin SULT2B1b to barrier function not yet shown here"]},{"year":2007,"claim":"Defined the C-terminal proline-rich domain as a stability determinant and catalogued allozyme variation, showing coding SNPs retain most activity but truncation causes aggregation and degradation.","evidence":"Mammalian expression, allozyme activity assays, protein stability assessment","pmids":["17496163"],"confidence":"Medium","gaps":["Physiological impact of allozyme variants in vivo unknown","Mechanism of aggregate formation not characterized"]},{"year":2013,"claim":"Reported nuclear localization of SULT2B1b linked to C-terminal serine phosphorylation, raising the possibility of regulated subcellular partitioning.","evidence":"Tissue fractionation and phosphorylation analysis summarized in review","pmids":["24020383"],"confidence":"Low","gaps":["Primary experimental methods not detailed; not independently confirmed","Functional role of nuclear pool undefined","Phosphosite not mapped"]},{"year":2017,"claim":"Established SULT2B1 as a disease gene, showing loss-of-function causes autosomal-recessive congenital ichthyosis through loss of epidermal cholesterol sulfate and unchecked keratinocyte proliferation.","evidence":"Whole-exome sequencing, patient keratinocytes, 3D organotypic culture, TLC of cholesterol metabolites","pmids":["28575648"],"confidence":"High","gaps":["Molecular signaling from cholesterol sulfate loss to proliferation not fully defined","Genotype-phenotype correlation across variants incomplete"]},{"year":2021,"claim":"Linked SULT2B1-derived cholesterol sulfate to anti-inflammatory macrophage programming via AMPK-CREB and NADPH/ROS control, with consequences for ischemic stroke severity.","evidence":"Sult2b1 KO mice, MCAO model, bone marrow transplant, monocyte depletion/adoptive transfer, CyTOF, BMDM assays","pmids":["34815805"],"confidence":"High","gaps":["Direct molecular target of cholesterol sulfate upstream of AMPK not identified","Relevance to human stroke untested"]},{"year":2023,"claim":"Identified the SULT2B1-cholesterol sulfate-DOCK2 axis, showing tumor-derived cholesterol sulfate suppresses DOCK2 activity to promote CD8+ T-cell exhaustion in HCC.","evidence":"Quasi-targeted metabolomics, CyTOF, RNA-seq, mouse HCC models, molecular docking","pmids":["36626623"],"confidence":"Medium","gaps":["Direct biochemical inhibition of DOCK2 by cholesterol sulfate not demonstrated in this study","Binding mode beyond docking simulation unconfirmed"]},{"year":2023,"claim":"Extended SULT2B1's macrophage role to LXR-controlled cholesterol efflux, showing its loss activates LXR-ABCA1/G1 to reduce M2 polarization and pathological choroidal neovascularization.","evidence":"Sult2b1 KO mice, CNV model, macrophage polarization assays, LXR inhibitor GSK2033","pmids":["37550000"],"confidence":"Medium","gaps":["Identity of the LXR-activating sterol ligand altered by SULT2B1 not pinned down","Whether the same axis operates in human AMD untested"]},{"year":2024,"claim":"Revealed a non-sulfotransferase, protein-interaction role for SULT2B1 in cancer, where it binds AKT, PKM2 and SCD1 to drive mTORC1 signaling, glycolysis and lipid metabolism.","evidence":"IP, GST pull-down, immunofluorescence, ChIP, autophagy reporter, orthotopic colon cancer models","pmids":["39623433","38372484"],"confidence":"Medium","gaps":["Whether catalytic activity is required for these interactions unknown","Direct binding interfaces and stoichiometry not mapped","Reciprocal validation of SCD1 interaction limited"]},{"year":2024,"claim":"Placed SULT2B1 under transcriptional control of oncogenic/exosomal inputs, identifying ETV4 and SMC1A as activators that couple SULT2B1 induction to HCC and colon cancer progression.","evidence":"Dual-luciferase reporter, ChIP, exosome co-culture, xenograft and orthotopic models","pmids":["39639836","38372484"],"confidence":"Medium","gaps":["Endogenous signals controlling these transcription factors in tumors unclear","Single-lab findings without independent replication"]},{"year":2024,"claim":"Connected SULT2B1 to nuclear oxysterol (25HC3S)-LXR signaling and a LncRNA gga3-204/SMAD4/Smad7 cascade that restrains NF-κB and macrophage inflammation in atherosclerosis.","evidence":"Sult2b1 knockdown in mouse AS model, nuclear fractionation, LncRNA expression analysis, in vivo/in vitro functional assays","pmids":["38286358"],"confidence":"Medium","gaps":["Direct molecular link between 25HC3S and gga3-204 transcription not established","Human relevance untested"]},{"year":2025,"claim":"Demonstrated in vivo epistasis confirming cholesterol sulfate as an endogenous DOCK2-Rac inhibitor in skin, where Sult2b1 loss worsens psoriatic dermatitis rescued by DOCK2 deletion or neutrophil depletion.","evidence":"Sult2b1 KO mice, imiquimod psoriasis model, Dock2 genetic deletion, neutrophil-depleting antibody, CS measurement, keratinocyte assays","pmids":["41181147"],"confidence":"High","gaps":["Direct biochemical inhibition of DOCK2 GEF activity by cholesterol sulfate not reconstituted","Threshold concentrations for in vivo inhibition unclear"]},{"year":2025,"claim":"Implicated SULT2B1 induction in cholangiocyte EMT via Wnt/β-catenin/MMP7 signaling downstream of TGF-β1.","evidence":"TGF-β1 treatment of bile duct epithelial cells, SULT2B1 silencing, pathway immunoblotting","pmids":["41402642"],"confidence":"Low","gaps":["Single cell-line model with pathway inferred from inhibitors; no direct biochemical mechanism","Whether sulfotransferase activity is required not tested"]},{"year":null,"claim":"How a single sulfotransferase product (cholesterol sulfate) is decoded into distinct, sometimes opposing cell-type-specific outputs — and whether SULT2B1's catalytic and protein-scaffolding (AKT/PKM2/SCD1) functions are mechanistically separable — remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structure of SULT2B1 bound to cholesterol or to AKT/PKM2/SCD1","Direct biochemical demonstration of DOCK2 inhibition by cholesterol sulfate lacking","Whether enzymatic activity is required for cancer protein-interaction phenotypes unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,1,2,3,6,16]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[10,12]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[5,13]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[1,6,10]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[7,8,9,13,15]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[12,14]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[6]}],"complexes":[],"partners":["AKT","PKM2","SCD1","DOCK2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O00204","full_name":"Sulfotransferase 2B1","aliases":["Alcohol sulfotransferase","Hydroxysteroid sulfotransferase 2","Sulfotransferase family 2B member 1","Sulfotransferase family cytosolic 2B member 1","ST2B1"],"length_aa":365,"mass_kda":41.3,"function":"Sulfotransferase that utilizes 3'-phospho-5'-adenylyl sulfate (PAPS) as sulfonate donor to catalyze the sulfate conjugation. Responsible for the sulfation of cholesterol (PubMed:12145317, PubMed:19589875). Catalyzes sulfation of the 3beta-hydroxyl groups of steroids, such as, pregnenolone and dehydroepiandrosterone (DHEA) (PubMed:12145317, PubMed:16855051, PubMed:21855633, PubMed:9799594). Preferentially sulfonates cholesterol, while it also has significant activity with pregnenolone and DHEA (PubMed:12145317, PubMed:21855633). Plays a role in epidermal cholesterol metabolism and in the regulation of epidermal proliferation and differentiation (PubMed:28575648) Sulfonates pregnenolone but not cholesterol","subcellular_location":"Cytoplasm, cytosol; Microsome; Nucleus","url":"https://www.uniprot.org/uniprotkb/O00204/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SULT2B1","classification":"Not Classified","n_dependent_lines":16,"n_total_lines":1208,"dependency_fraction":0.013245033112582781},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/SULT2B1","total_profiled":1310},"omim":[{"mim_id":"617571","title":"ICHTHYOSIS, CONGENITAL, AUTOSOMAL RECESSIVE 14; ARCI14","url":"https://www.omim.org/entry/617571"},{"mim_id":"604125","title":"SULFOTRANSFERASE FAMILY 2B, MEMBER 1; SULT2B1","url":"https://www.omim.org/entry/604125"},{"mim_id":"602423","title":"NUCLEAR RECEPTOR SUBFAMILY 1, GROUP H, MEMBER 3; NR1H3","url":"https://www.omim.org/entry/602423"},{"mim_id":"600380","title":"NUCLEAR RECEPTOR SUBFAMILY 1, GROUP H, MEMBER 2; NR1H2","url":"https://www.omim.org/entry/600380"},{"mim_id":"242300","title":"ICHTHYOSIS, CONGENITAL, AUTOSOMAL RECESSIVE 1; ARCI1","url":"https://www.omim.org/entry/242300"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Vesicles","reliability":"Enhanced"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"cervix","ntpm":105.9},{"tissue":"esophagus","ntpm":305.3},{"tissue":"skin 1","ntpm":195.8},{"tissue":"vagina","ntpm":152.9}],"url":"https://www.proteinatlas.org/search/SULT2B1"},"hgnc":{"alias_symbol":["HSST2"],"prev_symbol":[]},"alphafold":{"accession":"O00204","domains":[{"cath_id":"3.40.50.300","chopping":"23-302","consensus_level":"high","plddt":96.7188,"start":23,"end":302}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O00204","model_url":"https://alphafold.ebi.ac.uk/files/AF-O00204-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O00204-F1-predicted_aligned_error_v6.png","plddt_mean":86.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SULT2B1","jax_strain_url":"https://www.jax.org/strain/search?query=SULT2B1"},"sequence":{"accession":"O00204","fasta_url":"https://rest.uniprot.org/uniprotkb/O00204.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O00204/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O00204"}},"corpus_meta":[{"pmid":"9799594","id":"PMC_9799594","title":"Human hydroxysteroid sulfotransferase SULT2B1: two enzymes encoded by a single chromosome 19 gene.","date":"1998","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/9799594","citation_count":128,"is_preprint":false},{"pmid":"12145317","id":"PMC_12145317","title":"Mutational analysis of human hydroxysteroid sulfotransferase SULT2B1 isoforms reveals that exon 1B of the SULT2B1 gene produces cholesterol sulfotransferase, whereas exon 1A yields pregnenolone sulfotransferase.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12145317","citation_count":82,"is_preprint":false},{"pmid":"11594786","id":"PMC_11594786","title":"Biochemical characterization and tissue distribution of human SULT2B1.","date":"2001","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/11594786","citation_count":78,"is_preprint":false},{"pmid":"28575648","id":"PMC_28575648","title":"Mutations in SULT2B1 Cause Autosomal-Recessive Congenital Ichthyosis in Humans.","date":"2017","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28575648","citation_count":69,"is_preprint":false},{"pmid":"12639899","id":"PMC_12639899","title":"Conservation of the hydroxysteroid sulfotransferase SULT2B1 gene structure in the mouse: pre- and postnatal expression, kinetic analysis of isoforms, and comparison with prototypical SULT2A1.","date":"2003","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/12639899","citation_count":54,"is_preprint":false},{"pmid":"24020383","id":"PMC_24020383","title":"SULT2B1: unique properties and characteristics of a hydroxysteroid sulfotransferase family.","date":"2013","source":"Drug metabolism reviews","url":"https://pubmed.ncbi.nlm.nih.gov/24020383","citation_count":48,"is_preprint":false},{"pmid":"36626623","id":"PMC_36626623","title":"SULT2B1-CS-DOCK2 axis regulates effector T-cell exhaustion in HCC 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c-MYC.","date":"2021","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/34921134","citation_count":30,"is_preprint":false},{"pmid":"16368200","id":"PMC_16368200","title":"Cloning, characterization and tissue expression of rat SULT2B1a and SULT2B1b steroid/sterol sulfotransferase isoforms: divergence of the rat SULT2B1 gene structure from orthologous human and mouse genes.","date":"2005","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/16368200","citation_count":25,"is_preprint":false},{"pmid":"38372484","id":"PMC_38372484","title":"Sulfotransferase SULT2B1 facilitates colon cancer metastasis by promoting SCD1-mediated lipid metabolism.","date":"2024","source":"Clinical and translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38372484","citation_count":21,"is_preprint":false},{"pmid":"33079922","id":"PMC_33079922","title":"Verteporfin Promotes the Apoptosis and Inhibits the Proliferation, Migration, and Invasion of Cervical Cancer Cells by Downregulating SULT2B1 Expression.","date":"2020","source":"Medical science monitor : international medical journal of experimental and clinical research","url":"https://pubmed.ncbi.nlm.nih.gov/33079922","citation_count":13,"is_preprint":false},{"pmid":"29588428","id":"PMC_29588428","title":"SULFATION PATHWAYS: Expression of SULT2A1, SULT2B1 and HSD3B1 in the porcine testis and epididymis.","date":"2018","source":"Journal of molecular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/29588428","citation_count":12,"is_preprint":false},{"pmid":"37550000","id":"PMC_37550000","title":"Macrophage Sult2b1 promotes pathological neovascularization in age-related macular degeneration.","date":"2023","source":"Life science alliance","url":"https://pubmed.ncbi.nlm.nih.gov/37550000","citation_count":11,"is_preprint":false},{"pmid":"34730281","id":"PMC_34730281","title":"The promoter hypermethylation of SULT2B1 accelerates esophagus tumorigenesis via downregulated 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immunology","url":"https://pubmed.ncbi.nlm.nih.gov/41181147","citation_count":0,"is_preprint":false},{"pmid":"40287810","id":"PMC_40287810","title":"SPAG4 Regulates Glycolytic Metabolism in HT29 Cells as a Target via the c-MYC/SULT2B1 Pathway.","date":"2025","source":"Discovery medicine","url":"https://pubmed.ncbi.nlm.nih.gov/40287810","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":16458,"output_tokens":4281,"usd":0.056794,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12255,"output_tokens":4868,"usd":0.091487,"stage2_stop_reason":"end_turn"},"total_usd":0.148281,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"SULT2B1 encodes two distinct hydroxysteroid sulfotransferase isoforms (SULT2B1a and SULT2B1b) from a single gene via alternative transcription initiation and alternative splicing at different 5' exons. Both isoforms catalyze sulfation of dehydroepiandrosterone but not 4-nitrophenol or 17β-estradiol.\",\n      \"method\": \"cDNA cloning, COS-1 cell expression, enzymatic activity assays, Northern blot, genomic mapping\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct enzymatic reconstitution in mammalian cells with substrate specificity assays, cloning and gene structure fully characterized\",\n      \"pmids\": [\"9799594\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"SULT2B1b (exon 1B) functions as a cholesterol sulfotransferase, while SULT2B1a (exon 1A) functions as a pregnenolone sulfotransferase. The unique N-terminal amino acids of SULT2B1b, specifically isoleucines at positions 21 and 23, are critical for cholesterol sulfation activity. Deletion of the 53 amino acid C-terminal extension does not affect catalytic activity of either isoform.\",\n      \"method\": \"Deletion analysis, site-directed mutagenesis, enzymatic activity assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution with mutagenesis and deletion analysis, multiple orthogonal methods, precise residues identified\",\n      \"pmids\": [\"12145317\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Both SULT2B1a and SULT2B1b specifically catalyze sulfonation of 3β-hydroxysteroids with high catalytic efficiency, and both also sulfonate dihydrotestosterone. Tissue expression is detected in placenta, ovary, uterus, and prostate.\",\n      \"method\": \"In vitro enzymatic activity assays, kinetic analysis, tissue expression analysis\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro enzymatic characterization in single study with substrate specificity profiling, no independent replication cited\",\n      \"pmids\": [\"11594786\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Mouse SULT2B1 isoforms have predilection for cholesterol sulfation over SULT2A1; SULT2B1a is most abundantly expressed in brain and spinal cord (pregnenolone sulfotransferase activity), while SULT2B1b is predominantly expressed in skin (cholesterol sulfotransferase activity). Both isoforms derive from a single gene via alternative exon I.\",\n      \"method\": \"cDNA cloning, gene structure analysis, real-time RT-PCR, enzymatic characterization\",\n      \"journal\": \"Endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — enzymatic characterization plus tissue localization via qPCR, replicated structure of alternative splicing from human gene\",\n      \"pmids\": [\"12639899\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Deletion of the proline-rich SULT2B1 C-terminus results in intracellular protein aggregate formation and accelerated degradation of the truncated protein, demonstrating that the C-terminal domain is required for protein stability. Nonsynonymous coding SNPs produce variant allozymes with 64–98% of wild-type enzymatic activity.\",\n      \"method\": \"Mammalian expression system, functional genomics, allozyme activity assays, protein stability assessment\",\n      \"journal\": \"The Journal of pharmacology and experimental therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — deletion construct in mammalian expression system with protein stability readout; multiple allozymes tested\",\n      \"pmids\": [\"17496163\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"SULT2B1b shows nuclear localization in selected tissues, which appears related to serine phosphorylation of the carboxy-terminal peptide. Only SULT2B1b protein has been reliably detected in human tissues investigated.\",\n      \"method\": \"Tissue fractionation, protein localization studies, phosphorylation analysis (review with experimental basis cited)\",\n      \"journal\": \"Drug metabolism reviews\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — localization and phosphorylation claims reported in a review without detailed primary experimental methods described in the abstract\",\n      \"pmids\": [\"24020383\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Loss-of-function mutations in SULT2B1 cause autosomal-recessive congenital ichthyosis. SULT2B1-deficient keratinocytes in 3D organotypic cultures show absence of cholesterol sulfate and increased free cholesterol, indicating SULT2B1 is required for epidermal cholesterol sulfate synthesis. Loss of SULT2B1 leads to increased keratinocyte proliferation and thickened epithelial layers.\",\n      \"method\": \"Whole-exome sequencing, functional analysis of patient keratinocytes, 3D organotypic tissue culture, thin layer chromatography of cholesterol metabolites, RT-PCR, protein expression analysis\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct loss-of-function in patient-derived cells plus 3D model reconstitution with metabolite readout by TLC; multiple independent families and orthogonal methods\",\n      \"pmids\": [\"28575648\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Sult2b1 deficiency in mice exacerbates ischemic stroke outcomes; cholesterol sulfate produced by SULT2B1 attenuates pro-inflammatory macrophage polarization by regulating NADPH and ROS levels and activating AMPK-CREB signaling pathway. Peripheral monocyte-derived macrophages are the dominant cell type promoting pro-inflammatory status in Sult2b1-deficient mice after stroke.\",\n      \"method\": \"Sult2b1 knockout mice, transient MCAO model, bone marrow transplantation, immune cell depletion, adoptive monocyte transfer, CyTOF, primary BMDM assays\",\n      \"journal\": \"Theranostics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal approaches (KO, bone marrow transplant, cell depletion, adoptive transfer) with mechanistic pathway identification (AMPK-CREB)\",\n      \"pmids\": [\"34815805\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Cholesterol sulfate synthesized by SULT2B1 in HCC tumor cells suppresses DOCK2 enzymatic activity in T cells, promoting effector CD8+ T-cell exhaustion. This constitutes a SULT2B1-CS-DOCK2 axis regulating tumor-infiltrating lymphocyte function.\",\n      \"method\": \"Quasi-targeted metabolomics, mass spectrometry, mass cytometry (CyTOF), flow cytometry, RNA sequencing, mouse HCC models, molecular docking simulation\",\n      \"journal\": \"Hepatology (Baltimore, Md.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — metabolomics plus functional assays in mouse models identify cholesterol sulfate as the mediating metabolite, but direct biochemical inhibition of DOCK2 by CS requires further validation\",\n      \"pmids\": [\"36626623\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Macrophage SULT2B1 promotes pathological choroidal neovascularization in AMD by supporting M2 macrophage activation. Sult2b1 deficiency activates LXR signaling and increases ABCA1/ABCG1-mediated cholesterol efflux from M2 macrophages, reducing M2 polarization. STS (sterol desulfonase, opposing enzyme) protects against CNV by activating LXR-ABCA1/G1 signaling.\",\n      \"method\": \"Sult2b1 knockout mice, in vivo CNV model, in vitro macrophage polarization assays, LXR inhibitor (GSK2033) treatment\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mice with defined phenotypic and molecular readout, LXR pathway mechanism validated by pharmacological inhibition\",\n      \"pmids\": [\"37550000\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"SULT2B1 directly interacts with SCD1 (stearoyl-CoA desaturase 1) to facilitate lipid metabolism in colon cancer cells, and promotes metastasis. SMC1A transcriptionally upregulates SULT2B1 expression.\",\n      \"method\": \"Single-cell sequencing, proteomics, CC orthotopic mouse model, in vitro assays, co-immunoprecipitation (implied by 'directly interacted'), SULT2B1-KO\",\n      \"journal\": \"Clinical and translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — protein-protein interaction with SCD1 and transcriptional regulation by SMC1A reported, but methods for interaction are not fully detailed in abstract\",\n      \"pmids\": [\"38372484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ETV4 (from M2 macrophage-derived exosomes) transcriptionally activates SULT2B1 expression by binding to the SULT2B1 promoter, promoting HCC cell proliferation, glycolysis and stemness.\",\n      \"method\": \"Dual-luciferase reporter assay, chromatin immunoprecipitation (ChIP), exosome co-culture, xenograft mouse model\",\n      \"journal\": \"Liver international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and luciferase reporter establish ETV4 as transcriptional activator of SULT2B1, single lab study\",\n      \"pmids\": [\"39639836\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"SULT2B1 directly interacts with AKT and enhances AKT-mTORC1 signaling activity in colorectal cancer cells. SULT2B1 also binds PKM2 and regulates it at both transcriptional and protein degradation levels, promoting glycolysis and cell proliferation.\",\n      \"method\": \"Immunoprecipitation, GST pull-down assay, immunofluorescence, ChIP assay, mCherry-GFP-LC3 autophagy assay, small molecule agonist/antagonist validation\",\n      \"journal\": \"Journal of translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal pulldown (IP + GST) for AKT and PKM2 interactions, multiple orthogonal methods in single lab\",\n      \"pmids\": [\"39623433\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Suppression of SULT2B1 in macrophages reduces nuclear 25HC3S levels, elevates LXR expression, and increases transcription of LncRNA gga3-204. LncRNA gga3-204 binds SMAD4, facilitating its nuclear entry to regulate Smad7 transcription, suppressing NF-κB nuclear entry and attenuating macrophage inflammation in atherosclerosis.\",\n      \"method\": \"Sult2b1 knockdown in mouse AS model, nuclear fractionation, LncRNA expression analysis, in vivo and in vitro functional assays\",\n      \"journal\": \"Translational research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multi-step pathway established by KD experiments in vivo and in vitro with molecular readouts, single lab\",\n      \"pmids\": [\"38286358\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TGF-β1 induces SULT2B1 overexpression in cholangiocytes, which activates the Wnt/β-catenin/MMP7 pathway to promote epithelial-mesenchymal transition (EMT). Silencing SULT2B1 blocks Wnt/β-catenin/MMP7-mediated cholangiocyte EMT.\",\n      \"method\": \"In vitro TGF-β1 treatment of human intrahepatic bile duct epithelial cells, SULT2B1 silencing, pathway analysis by immunoblotting\",\n      \"journal\": \"Pediatric research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single cell-line model, pathway inferred from knockdown and pathway inhibitor experiments without direct biochemical mechanism\",\n      \"pmids\": [\"41402642\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SULT2B1-produced cholesterol sulfate (CS) acts as an endogenous DOCK2-inhibitory metabolite in the skin, suppressing immune cell migration and activation. Sult2b1 knockout in mice exacerbates imiquimod-induced psoriatic dermatitis with enhanced neutrophil recruitment; genetic deletion of DOCK2 or neutrophil depletion alleviates the worsened dermatitis in Sult2b1 KO mice, establishing epistasis between SULT2B1-CS and DOCK2-mediated Rac activation.\",\n      \"method\": \"Sult2b1 knockout mice, imiquimod psoriasis model, Dock2 genetic deletion, neutrophil-depleting antibody treatment, CS measurement, human keratinocyte cytokine stimulation assays\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis (double KO rescue), pharmacological validation, multiple orthogonal methods establishing CS-DOCK2 mechanistic axis in vivo\",\n      \"pmids\": [\"41181147\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SULT2B1b allozymes with nonsynonymous SNPs show differential sulfating activities and altered kinetic parameters (substrate-binding affinity and catalytic activity) toward DHEA and pregnenolone compared to wild-type SULT2B1b.\",\n      \"method\": \"Expression of allozymes in heterologous system, kinetic analysis (Km, Vmax determination) toward DHEA and pregnenolone\",\n      \"journal\": \"Molecular and cellular endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — rigorous kinetic characterization of allozymes but single lab with no independent replication\",\n      \"pmids\": [\"31400397\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SULT2B1 is a cytosolic sulfotransferase encoded by a single gene that generates two isoforms (SULT2B1a and SULT2B1b) via alternative transcription initiation and splicing: SULT2B1b acts primarily as a cholesterol sulfotransferase (requiring N-terminal isoleucines at positions 21/23), while SULT2B1a preferentially sulfates pregnenolone; the cholesterol sulfate product regulates multiple downstream processes including epidermal barrier formation, macrophage polarization (via AMPK-CREB and LXR-ABCA1/G1 pathways), CD8+ T-cell exhaustion (by inhibiting DOCK2-Rac activity), and skin immune homeostasis, while SULT2B1 protein itself interacts with AKT and PKM2 to modulate glycolysis and cancer cell signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SULT2B1 is a cytosolic hydroxysteroid sulfotransferase that catalyzes the sulfonation of 3β-hydroxysteroids, encoded by a single gene that produces two isoforms via alternative transcription initiation and 5'-exon splicing: SULT2B1b, which preferentially sulfates cholesterol, and SULT2B1a, which preferentially sulfates pregnenolone [#0, #1, #3]. The distinct N-terminal sequence of SULT2B1b — specifically isoleucines at positions 21 and 23 — confers its cholesterol sulfotransferase activity, while a proline-rich C-terminal extension is dispensable for catalysis but required for protein stability [#1, #4]. The principal product, cholesterol sulfate, mediates most downstream physiology: SULT2B1 supplies epidermal cholesterol sulfate and restrains keratinocyte proliferation, and biallelic loss-of-function mutations cause autosomal-recessive congenital ichthyosis [#6]. Cholesterol sulfate generated by SULT2B1 functions as an endogenous inhibitor of DOCK2-driven Rac activation, an axis that suppresses CD8+ T-cell exhaustion in hepatocellular carcinoma and limits neutrophil-driven psoriatic skin inflammation [#8, #15]. In macrophages, SULT2B1-dependent sterol sulfation tunes inflammatory polarization through AMPK-CREB signaling and through nuclear oxysterol/LXR-ABCA1/G1 control of cholesterol efflux, influencing ischemic stroke, choroidal neovascularization, and atherosclerosis [#7, #9, #13]. Beyond its sterol-sulfating role, SULT2B1 protein physically engages metabolic and signaling effectors — AKT and PKM2 to drive mTORC1 signaling and glycolysis, and SCD1 to support lipid metabolism — promoting proliferation and metastasis in gastrointestinal cancers, where it is transcriptionally induced by ETV4, SMC1A, and TGF-β1 [#10, #11, #12].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established that a single SULT2B1 gene generates two hydroxysteroid sulfotransferase isoforms with shared DHEA-sulfating but distinct substrate boundaries, defining the gene's basic architecture.\",\n      \"evidence\": \"cDNA cloning, COS-1 expression and enzymatic assays, Northern blot, genomic mapping\",\n      \"pmids\": [\"9799594\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological substrate preferences of each isoform not yet resolved\", \"Tissue-specific isoform deployment not yet mapped\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Refined the catalytic profile, showing both isoforms efficiently sulfonate 3β-hydroxysteroids and dihydrotestosterone, with expression in reproductive tissues.\",\n      \"evidence\": \"In vitro kinetic assays and tissue expression analysis\",\n      \"pmids\": [\"11594786\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-study characterization without independent replication\", \"In vivo relevance of DHT sulfation unestablished\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Resolved the isoform functional dichotomy and its structural basis, attributing cholesterol sulfotransferase activity of SULT2B1b to N-terminal isoleucines 21/23 and showing the C-terminal extension is dispensable for catalysis.\",\n      \"evidence\": \"Deletion analysis, site-directed mutagenesis, enzymatic assays\",\n      \"pmids\": [\"12145317\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural mechanism by which Ile21/23 enable cholesterol binding not solved\", \"Function of the C-terminal extension not yet defined\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Confirmed the conserved isoform architecture in mouse and mapped tissue specialization — SULT2B1a in brain/spinal cord, SULT2B1b in skin — linking each isoform's activity to its dominant tissue.\",\n      \"evidence\": \"cDNA cloning, gene structure analysis, real-time RT-PCR, enzymatic characterization in mouse\",\n      \"pmids\": [\"12639899\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of brain pregnenolone sulfation not tested\", \"Causal link of skin SULT2B1b to barrier function not yet shown here\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Defined the C-terminal proline-rich domain as a stability determinant and catalogued allozyme variation, showing coding SNPs retain most activity but truncation causes aggregation and degradation.\",\n      \"evidence\": \"Mammalian expression, allozyme activity assays, protein stability assessment\",\n      \"pmids\": [\"17496163\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological impact of allozyme variants in vivo unknown\", \"Mechanism of aggregate formation not characterized\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Reported nuclear localization of SULT2B1b linked to C-terminal serine phosphorylation, raising the possibility of regulated subcellular partitioning.\",\n      \"evidence\": \"Tissue fractionation and phosphorylation analysis summarized in review\",\n      \"pmids\": [\"24020383\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Primary experimental methods not detailed; not independently confirmed\", \"Functional role of nuclear pool undefined\", \"Phosphosite not mapped\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Established SULT2B1 as a disease gene, showing loss-of-function causes autosomal-recessive congenital ichthyosis through loss of epidermal cholesterol sulfate and unchecked keratinocyte proliferation.\",\n      \"evidence\": \"Whole-exome sequencing, patient keratinocytes, 3D organotypic culture, TLC of cholesterol metabolites\",\n      \"pmids\": [\"28575648\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular signaling from cholesterol sulfate loss to proliferation not fully defined\", \"Genotype-phenotype correlation across variants incomplete\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Linked SULT2B1-derived cholesterol sulfate to anti-inflammatory macrophage programming via AMPK-CREB and NADPH/ROS control, with consequences for ischemic stroke severity.\",\n      \"evidence\": \"Sult2b1 KO mice, MCAO model, bone marrow transplant, monocyte depletion/adoptive transfer, CyTOF, BMDM assays\",\n      \"pmids\": [\"34815805\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct molecular target of cholesterol sulfate upstream of AMPK not identified\", \"Relevance to human stroke untested\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified the SULT2B1-cholesterol sulfate-DOCK2 axis, showing tumor-derived cholesterol sulfate suppresses DOCK2 activity to promote CD8+ T-cell exhaustion in HCC.\",\n      \"evidence\": \"Quasi-targeted metabolomics, CyTOF, RNA-seq, mouse HCC models, molecular docking\",\n      \"pmids\": [\"36626623\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical inhibition of DOCK2 by cholesterol sulfate not demonstrated in this study\", \"Binding mode beyond docking simulation unconfirmed\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended SULT2B1's macrophage role to LXR-controlled cholesterol efflux, showing its loss activates LXR-ABCA1/G1 to reduce M2 polarization and pathological choroidal neovascularization.\",\n      \"evidence\": \"Sult2b1 KO mice, CNV model, macrophage polarization assays, LXR inhibitor GSK2033\",\n      \"pmids\": [\"37550000\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Identity of the LXR-activating sterol ligand altered by SULT2B1 not pinned down\", \"Whether the same axis operates in human AMD untested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Revealed a non-sulfotransferase, protein-interaction role for SULT2B1 in cancer, where it binds AKT, PKM2 and SCD1 to drive mTORC1 signaling, glycolysis and lipid metabolism.\",\n      \"evidence\": \"IP, GST pull-down, immunofluorescence, ChIP, autophagy reporter, orthotopic colon cancer models\",\n      \"pmids\": [\"39623433\", \"38372484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether catalytic activity is required for these interactions unknown\", \"Direct binding interfaces and stoichiometry not mapped\", \"Reciprocal validation of SCD1 interaction limited\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Placed SULT2B1 under transcriptional control of oncogenic/exosomal inputs, identifying ETV4 and SMC1A as activators that couple SULT2B1 induction to HCC and colon cancer progression.\",\n      \"evidence\": \"Dual-luciferase reporter, ChIP, exosome co-culture, xenograft and orthotopic models\",\n      \"pmids\": [\"39639836\", \"38372484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endogenous signals controlling these transcription factors in tumors unclear\", \"Single-lab findings without independent replication\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Connected SULT2B1 to nuclear oxysterol (25HC3S)-LXR signaling and a LncRNA gga3-204/SMAD4/Smad7 cascade that restrains NF-κB and macrophage inflammation in atherosclerosis.\",\n      \"evidence\": \"Sult2b1 knockdown in mouse AS model, nuclear fractionation, LncRNA expression analysis, in vivo/in vitro functional assays\",\n      \"pmids\": [\"38286358\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular link between 25HC3S and gga3-204 transcription not established\", \"Human relevance untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated in vivo epistasis confirming cholesterol sulfate as an endogenous DOCK2-Rac inhibitor in skin, where Sult2b1 loss worsens psoriatic dermatitis rescued by DOCK2 deletion or neutrophil depletion.\",\n      \"evidence\": \"Sult2b1 KO mice, imiquimod psoriasis model, Dock2 genetic deletion, neutrophil-depleting antibody, CS measurement, keratinocyte assays\",\n      \"pmids\": [\"41181147\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct biochemical inhibition of DOCK2 GEF activity by cholesterol sulfate not reconstituted\", \"Threshold concentrations for in vivo inhibition unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Implicated SULT2B1 induction in cholangiocyte EMT via Wnt/β-catenin/MMP7 signaling downstream of TGF-β1.\",\n      \"evidence\": \"TGF-β1 treatment of bile duct epithelial cells, SULT2B1 silencing, pathway immunoblotting\",\n      \"pmids\": [\"41402642\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single cell-line model with pathway inferred from inhibitors; no direct biochemical mechanism\", \"Whether sulfotransferase activity is required not tested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single sulfotransferase product (cholesterol sulfate) is decoded into distinct, sometimes opposing cell-type-specific outputs — and whether SULT2B1's catalytic and protein-scaffolding (AKT/PKM2/SCD1) functions are mechanistically separable — remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structure of SULT2B1 bound to cholesterol or to AKT/PKM2/SCD1\", \"Direct biochemical demonstration of DOCK2 inhibition by cholesterol sulfate lacking\", \"Whether enzymatic activity is required for cancer protein-interaction phenotypes unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 1, 2, 3, 6, 16]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [10, 12]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [5, 13]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [1, 6, 10]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [7, 8, 9, 13, 15]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [12, 14]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"AKT\", \"PKM2\", \"SCD1\", \"DOCK2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}