{"gene":"SULF1","run_date":"2026-06-10T10:51:54","timeline":{"discoveries":[{"year":2003,"finding":"HSulf-1 is a cell surface-associated heparan sulfate 6-O-endosulfatase that selectively removes 6-O-sulfate groups from cell surface HSPGs, thereby diminishing receptor tyrosine kinase phosphorylation (including FGFR and EGFR family members) and downstream ERK signaling stimulated by heparin-binding growth factors FGF-2 and HB-EGF.","method":"Re-expression of HSulf-1 in ovarian cancer cell lines; measurement of HSPG sulfation, RTK phosphorylation, and ERK pathway activation","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (sulfation assays, RTK phosphorylation, downstream ERK signaling, proliferation/apoptosis readouts) in a focused mechanistic study; replicated in subsequent papers","pmids":["12686563"],"is_preprint":false},{"year":2004,"finding":"HSulf-1 re-expression attenuates HGF-mediated phosphorylation of c-Met, and downstream ERK/MAPK and AKT signaling, and reduces HGF-driven cell motility and invasion in head and neck squamous carcinoma cells.","method":"Stable transfection of HSulf-1 in SCCHN lines; RTK phosphorylation assays, transwell invasion/migration assay, thymidine incorporation","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal gain-of-function with multiple signaling and functional readouts; extends mechanism to HGF/c-Met axis","pmids":["14973553"],"is_preprint":false},{"year":2005,"finding":"HSulf-1 and HSulf-2 suppress myeloma tumor growth in vivo, and their extracellular sulfatase activity is restricted to the local tumor cell surface; Sulfs also promote extracellular matrix deposition within tumors.","method":"Transfection of myeloma cells with HSulf-1 or HSulf-2 cDNA; SCID mouse xenograft model; histological analysis of ECM","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo xenograft with histological readouts; single lab, multiple endpoints","pmids":["16192265"],"is_preprint":false},{"year":2006,"finding":"HSulf-1 expression inhibits angiogenesis by impairing formation of a FGF-2/FGFR1c/heparan sulfate ternary complex on vascular endothelial cells; HSulf-1 knockdown in HUVEC cells enhances FGF-2, HGF, and VEGF165 (but not heparan sulfate-independent VEGF121) proliferative signaling through ERK.","method":"Breast carcinoma xenografts with stable HSulf-1 clones; CD31 staining; Matrigel plug assay; shRNA knockdown in HUVEC; co-immunoprecipitation of FGF-2/FGFR1c/HS complex; ERK phosphorylation","journal":"Cancer research","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo and in vitro experiments, Co-IP of ternary complex, specific growth factor dependence on HS sulfation established by VEGF121 negative control","pmids":["16778174"],"is_preprint":false},{"year":2006,"finding":"SULF1 increases histone H4 acetylation in HCC cells by modulating cellular HDAC and histone acetyltransferase activities, and potentiates apoptosis induced by HDAC inhibitors; SULF1 knockdown upregulates phospho-AKT and phospho-ERK.","method":"Forced SULF1 expression in Huh7 and Hep3B; HDAC/HAT activity assays; shRNA knockdown; nude mouse xenografts; Western blot for p-AKT, p-ERK","journal":"Gastroenterology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple functional assays in vitro and in vivo; single lab","pmids":["16762634"],"is_preprint":false},{"year":2007,"finding":"SULF1 and SULF2 are the major regulators of heparan sulfate 6-O-desulfation in vivo; they reduce GDNF binding to heparan sulfate and thereby enhance GDNF signaling and neurite sprouting required for esophageal innervation. Sulf1/Sulf2 double-knockout mice exhibit esophageal contractile malfunction due to loss of GDNF-dependent neural innervation.","method":"Sulf1/Sulf2 genetic mouse knockouts; biochemical HS desulfation assays; GDNF binding assay; neurite sprouting assay; esophageal function tests","journal":"Development (Cambridge, England)","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — genetic loss-of-function in mice with biochemical (GDNF-HS binding), cell signaling, and organ-level functional readouts; neurite sprouting specificity established by GDNF vs. neurotrophin controls","pmids":["17720696"],"is_preprint":false},{"year":2007,"finding":"HSulf-1 expression is epigenetically silenced in ovarian cancer through CpG methylation of exon 1A and increased histone H3 methylation at the HSulf-1 locus; treatment with 5-aza-2'-deoxycytidine restores HSulf-1 transcription.","method":"Bisulfite sequencing of CpG sites; chromatin immunoprecipitation (H3 methylation); 5-aza-dC treatment; siRNA knockdown functional assays","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP + bisulfite sequencing + pharmacological demethylation; single lab","pmids":["17310998"],"is_preprint":false},{"year":2007,"finding":"HSulf-1 inhibits autocrine EGFR-ERK pathway activation driven by the heparin-binding EGF family members amphiregulin and HB-EGF in breast cancer cells; this is associated with reduced cyclin D1 levels and altered cell cycle distribution.","method":"shRNA knockdown of HSulf-1 in stable clonal lines; neutralizing antibodies against amphiregulin and HB-EGF; ERK phosphorylation; cyclin D1 Western blot; cell cycle analysis","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (shRNA, neutralizing antibodies, signaling readouts); single lab","pmids":["17363371"],"is_preprint":false},{"year":2007,"finding":"Asparagine-linked (N-linked) glycosylation of Sulf1 is essential for its enzymatic activity, membrane targeting, secretion, and heparin/HS binding; N-glycanase cleavage of N-linked glycans abolishes 6-O-desulfation activity.","method":"Domain mapping with deletion mutants; glycosylation inhibitor studies; N-glycanase cleavage; heparin binding and enzymatic activity assays on quail Sulf1 (ortholog)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct biochemical enzymatic assays combined with pharmacological and enzymatic N-glycan removal; multiple orthogonal methods in single study","pmids":["17855356"],"is_preprint":false},{"year":2009,"finding":"The unique hydrophilic domain (HD, ~320 aa) of Sulf1 is required for enzymatic activity and acts as a high-affinity heparin/heparan sulfate interaction domain; surface plasmon resonance indicates nanomolar affinity; HD binding to HS depends on presence of 6-O-sulfate substrate groups, suggesting substrate turnover facilitates enzyme release; deletion of the inner HD region increases Sulf1 secretion without affecting activity.","method":"HD deletion mutants; GST-HD fusion proteins; surface plasmon resonance; heparinase sensitivity; cell surface binding assays; FGF-2 signaling assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution with multiple deletion constructs, SPR kinetic measurements, functional signaling validation; rigorous domain-function mapping","pmids":["19666466"],"is_preprint":false},{"year":2009,"finding":"HSulf-1 and HSulf-2 selectively remove 6-O-sulfate groups from N,6-O,2-O-trisulfated disaccharides of intact heparan sulfate on the cell surface and extracellular matrix, as detected by flow cytometry with anti-HS antibody RB4CD12; both Sulf activities are potently inhibited by PI-88, a sulfated heparin mimetic.","method":"Flow cytometry with anti-HS antibody; disaccharide compositional analysis; ELISA with recombinant HSulfs; conditioned medium activity on microvessels; PI-88 inhibition assay","journal":"Glycobiology","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct enzymatic assays on cell surface and purified substrates; multiple orthogonal detection methods; inhibitor characterization","pmids":["19822709"],"is_preprint":false},{"year":2009,"finding":"vHNF1 (variant hepatic nuclear factor 1, encoded by TCF2/HNF1β) directly represses HSulf-1 transcription by binding to two vHNF1-responsive elements in the HSulf-1 promoter; shRNA knockdown of vHNF1 increases HSulf-1 expression and sensitizes cells to cisplatin/paclitaxel.","method":"Chromatin immunoprecipitation; reporter assay; shRNA knockdown of vHNF1; Western blot; xenograft experiments","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and reporter assay with functional rescue; single lab","pmids":["19487294"],"is_preprint":false},{"year":2009,"finding":"Promoter hypermethylation of the HSulf-1 5' regulatory region (approximately 400 bp with high basal promoter activity) correlates with HSulf-1 silencing in breast and gastric cancer cell lines and primary tumors.","method":"Luciferase reporter to characterize promoter; bisulfite sequencing; correlation with mRNA expression; cell-free DNA methylation in patient serum","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — promoter characterization with reporter assay plus bisulfite sequencing; single lab","pmids":["19006069"],"is_preprint":false},{"year":2010,"finding":"Haploinsufficiency of SULF1 (due to interstitial deletion at 8q13) is strongly implicated in mesomelia-synostoses syndrome, a skeletal dysplasia with mesomelic limb shortening and acral synostoses; SULF1 shows highest transcript levels in human osteoblasts and cartilage.","method":"Whole-genome array CGH in MSS patients; breakpoint sequencing; quantitative RT-PCR of SULF1 in human tissues","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genomic deletion mapping with quantitative expression analysis; genetic evidence from multiple unrelated families","pmids":["20602915"],"is_preprint":false},{"year":2011,"finding":"HSulf-1 transcription is downregulated by hypoxia through HIF-1α and HIF-2α recruitment to two functional hypoxia-responsive elements (HREs) on the HSulf-1 promoter; HSulf-1 depletion under hypoxia enhances FGF2 signaling through FGFR2 and promotes cell migration and invasion.","method":"Chromatin immunoprecipitation with HIF-1α and HIF-2α antibodies; HIF-1α shRNA rescue experiments; shRNA depletion of HSulf-1 and FGFR2; migration/invasion assays under hypoxia","journal":"Cancer research","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP identifies HIF binding to native promoter, genetic rescue with HIF-1α knockdown, orthogonal FGFR2 depletion confirms pathway; multiple methods","pmids":["21266348"],"is_preprint":false},{"year":2011,"finding":"hSulf-1 re-expression downregulates VEGFR-2 phosphorylation and inhibits angiogenesis in ovarian and hepatocellular cancer cells and xenografts; hSulf-1 knockdown enhances VEGFR-2 phosphorylation.","method":"hSulf-1 expression vectors and shRNA; Western blot for p-VEGFR-2; nude mouse xenografts; tumor microvessel density (CD31 staining)","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — paired gain- and loss-of-function in vitro and in vivo; single lab","pmids":["21853101"],"is_preprint":false},{"year":2012,"finding":"Sulf1 and Sulf2 have distinct organ-specific effects on heparan sulfate sulfation in vivo: Sulf1 knockout mice show predominant increases in ΔUA2S-GlcNS6S (trisulfated) disaccharides, with Sulf1 having greater overall impact on HS desulfation than Sulf2 despite lower mRNA levels; Sulfs do not alter chondroitin sulfate composition.","method":"Disaccharide analysis of HS from multiple organs of Sulf1 and Sulf2 knockout mice; correlation of mRNA expression with HS changes","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vivo biochemical disaccharide analysis across 8 organs in genetic knockouts; demonstrates substrate specificity for HS over chondroitin sulfate","pmids":["22298771"],"is_preprint":false},{"year":2012,"finding":"SULF1 inhibits heparan sulfate-dependent Wnt/β-catenin signaling at the cell surface in gastric cancer cells that depend on extracellular Wnt signaling (MKN28), but has no effect in cells with constitutively active intracellular Wnt/β-catenin (AGS); Wnt3a rescue and β-catenin shRNA confirm pathway dependence; HSulf-1 alters HS structure on cell surface.","method":"HSulf-1 stable transfection; TCF/LEF reporter assay; Western blot for β-catenin target genes; Wnt3a cDNA rescue; β-catenin shRNA; HSPG epitope analysis","journal":"Cancer science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal approaches including reporter, rescue, and shRNA; pathway specificity tested with two cell lines; single lab","pmids":["21722266"],"is_preprint":false},{"year":2013,"finding":"The hydrophilic domain (HD) of Sulf1 mediates specific HS binding through at least two separate binding sites (inner and C-terminal regions of HD); substrate turnover autoregulates Sulf1/HS association (Sulf1 binds 6-O-desulfated HS significantly weaker); dynamic single-molecule force spectroscopy reveals HD off-rate ~500-fold higher than SPR-determined value, consistent with processive action along HS chains.","method":"Affinity chromatography; AFM single-molecule force spectroscopy; immunofluorescence on living cells; HD subdomain deletion constructs","journal":"Biochimica et biophysica acta","confidence":"High","confidence_rationale":"Tier 1 / Moderate — single-molecule biophysics combined with biochemical domain mapping; novel autoregulation mechanism directly demonstrated","pmids":["23891937"],"is_preprint":false},{"year":2013,"finding":"Drosophila Sulf1 (ortholog) reduces extracellular Wnt/Wingless protein levels by facilitating Wg degradation; it inhibits Wg binding to the HSPG Dally; human Sulf1 expressed in Drosophila wing disc similarly lowers extracellular Wg levels, demonstrating conserved intrinsic activity.","method":"In vitro, in vivo, and ex vivo Wg stability assays in Drosophila; HS-Wg binding assay; human SULF1 expression in Drosophila disc","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple systems (in vitro, in vivo, ex vivo); mechanistic insight into Wg degradation; Drosophila ortholog with human SULF1 cross-species validation","pmids":["23300081"],"is_preprint":false},{"year":2013,"finding":"Sulf1 knockdown in zebrafish results in decreased BMP signaling, reduced Pax7-expressing dermomyotome cells, loss of sdf1/cxcl12 expression, and impaired somite morphogenesis/myoseptum formation; pharmacological BMP inhibition rescues Pax7 expression, myoseptum, and pigmentation; FGF pathway activation rescues neuromast spacing.","method":"Antisense morpholino knockdown in zebrafish; pharmacological BMP and FGF pathway inhibitors/activators; in situ hybridization; immunofluorescence","journal":"Developmental biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockdown with pharmacological epistasis testing; two independent pathways tested; zebrafish ortholog","pmids":["23583585"],"is_preprint":false},{"year":2014,"finding":"Sulf1 restricts Shh ligand diffusion and shapes the Shh morphogen gradient in the ventral neural tube of Xenopus; Sulf1 knockdown results in a less steep Shh gradient and altered ventral neural progenitor specification.","method":"Single-cell injection of GFP-tagged Shh mRNA in Xenopus embryos; Sulf1 morpholino knockdown; endogenous Shh distribution analysis; neural progenitor marker analysis","journal":"Developmental biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live imaging of morphogen gradients combined with loss-of-function; single lab, Xenopus ortholog","pmids":["24768893"],"is_preprint":false},{"year":2014,"finding":"Sulf1 in zebrafish regulates VegfA165-mediated arterial specification; sulf1 morphants lack arterial identity (reduced notch, ephrinB2) with increased venous marker flt4 in dorsal aorta; co-injection of vegfa165 mRNA rescues circulatory defects; in vitro, lack of SULF1 downregulates VEGFA-mediated arterial marker expression.","method":"Antisense morpholino knockdown in zebrafish; mRNA rescue injection; in situ hybridization for arterial/venous markers; in vitro VEGFA signaling assays","journal":"Angiogenesis","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — morpholino knockdown with mRNA rescue and pathway marker analysis in vivo plus in vitro validation; zebrafish ortholog","pmids":["23959107"],"is_preprint":false},{"year":2014,"finding":"Loss of HSulf-1 in ovarian cancer promotes tumorigenicity by decreasing proapoptotic Bim protein expression; decreased Bim is mediated by increased p-ERK signaling (rescued by ERK inhibitor PD98059); PI3K/AKT inhibition has no effect on Bim levels; rescue of Bim in HSulf-1 knockdown cells retards tumor growth in vivo.","method":"shRNA stable knockdown; Western blot for Bim; ERK inhibitor (PD98059) and PI3K inhibitor (LY294002) treatment; rescue Bim expression; soft agar colony assay; nude mouse xenografts","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological and genetic epistasis linking HSulf-1 loss → ERK → Bim; specific pathway exclusion (AKT negative); single lab","pmids":["24596063"],"is_preprint":false},{"year":2015,"finding":"The hydrophilic domain (HD) of Sulf1 exhibits catch bond behavior with its glycosaminoglycan (HS) substrate: bond lifetime increases under force for 6-O-sulfated HS but shows only slip bond interaction when 6-O-sulfation is absent; two coupled slip-bond states underlie the catch bond, with energy difference ΔE ≈ 9 kBT and compliance length Δx ≈ 3.2 nm.","method":"AFM-based force clamp spectroscopy and dynamic force spectroscopy; two-state two-path theoretical model fitting; comparison of 6-O-sulfated vs. desulfated GAG substrates","journal":"Biophysical journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — quantitative single-molecule biophysics with two orthogonal AFM modes; mechanistic model with defined energy landscape; substrate specificity confirmed by desulfated GAG control","pmids":["25863062"],"is_preprint":false},{"year":2015,"finding":"Sulf1 has ligand-specific effects on Wnt signaling in Xenopus: Sulf1 overexpression inhibits canonical Wnt8a signaling while enhancing non-canonical Wnt11b signaling; Sulf1 differentially affects membrane accumulation and extracellular levels of Wnt8a and Wnt11b tagged ligands.","method":"Xenopus assays; fluorescently tagged Wnt ligands in ectodermal explants; canonical and non-canonical Wnt pathway reporters; mRNA overexpression","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — well-established Xenopus assays with multiple Wnt ligands; ligand-specific effects established by direct comparison; single lab","pmids":["25681501"],"is_preprint":false},{"year":2015,"finding":"Sulf1 deficiency in cerebellar granule cells leads to reduced neurite length, reduced cell survival, and reduced migration capacity; impairments correlate with Sulf-specific alterations in FGF2, GDNF, and NGF signaling, but not Shh signaling; biochemical analysis reveals Sulf1-specific changes in 6-O-, 2-O- and N-sulfation of cerebellar HS in vivo.","method":"Primary cerebellar granule cells from Sulf1 KO mice; neurite length measurement; cell survival assays; migration assays; signaling pathway analysis; HS biochemical disaccharide analysis; HS epitope immunostaining","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with multiple cellular and biochemical readouts; signaling pathway specificity established; single lab","pmids":["26448642"],"is_preprint":false},{"year":2015,"finding":"HSulf-1 loss promotes aerobic glycolysis (Warburg effect) in ovarian cancer by upregulating glycolytic genes (Glut1, HKII, LDHA) and metabolites; this occurs mechanistically through HB-EGF-mediated p-ERK activation driving c-Myc induction; increased inhibitory PDH phosphorylation blocks glucose flux into TCA cycle; HSulf-1 overexpression reverses the glycolytic phenotype.","method":"shRNA knockdown and overexpression; isotope tracer metabolomics (glucose flux into TCA); metabolomic profiling; Western blot for glycolytic enzymes; pharmacological inhibition of c-Myc; oxygen consumption rate measurement","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — isotope tracer metabolomics plus pharmacological c-Myc inhibition establishing mechanistic pathway; multiple orthogonal methods; single lab","pmids":["26378042"],"is_preprint":false},{"year":2016,"finding":"TNF-α induces Sulf-1 expression in fibroblasts via NF-κB, ERK1/2, and p38 MAPK pathways; TNF-α-induced Sulf-1 is secreted as an active enzyme that causes 6-O-desulfation of HS and reduces ERK1/2 activation and proliferation in response to FGF-1; Sulf-1 siRNA rescues FGF-1-induced responses in TNF-α-treated cells.","method":"TNF-α treatment of MRC-5 fibroblasts; pathway inhibitors for NF-κB/ERK1/2/p38; HS disaccharide compositional analysis; siRNA knockdown of Sulf-1; ERK phosphorylation and proliferation assays","journal":"The international journal of biochemistry & cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA rescue confirms causal role; HS compositional analysis; pathway inhibitors identify upstream regulators; single lab","pmids":["27693418"],"is_preprint":false},{"year":2017,"finding":"Sulf1 and Sulf2 are required for corticospinal tract (CST) axon guidance: in DKO mice, increased 6-O-sulfated HS causes abnormal accumulation of Slit2 protein on brain surfaces, which repels CST axons dorsally; in utero electroporation of Sulf1/2 into radial glia rescues the CST defect; proteomic analysis identified Slit2 as the key molecule.","method":"Sulf1/Sulf2 double-KO mice; in utero electroporation rescue; immunofluorescence for Slit2; proteomics; CST tract tracing","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO, in utero rescue, proteomics, and functional imaging; Slit2 identified by unbiased proteomics and functionally validated as key molecular mediator","pmids":["29062064"],"is_preprint":false},{"year":2019,"finding":"SULF1 loss was identified as contributing to cisplatin resistance in ovarian cancer cells by genome-scale CRISPR/Cas9 knockout screening; CCK-8 and RT-PCR validation confirmed SULF1 involvement in cisplatin sensitivity.","method":"Genome-scale CRISPR/Cas9 knockout (GeCKO) library screen; CCK-8 viability assay; RT-PCR validation","journal":"American journal of cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — unbiased genome-wide screen with direct validation; replicates prior mechanistic observations on cisplatin resistance","pmids":["31218106"],"is_preprint":false},{"year":2020,"finding":"SULF1 produced by bone marrow fibroblasts suppresses Wnt3A-driven growth of prostate cancer cells in a 3D biomimetic triculture model incorporating perlecan (HSPG2); M2-like macrophages increase SULF1 and HSPG2 levels produced by fibroblasts.","method":"SULF1 CRISPR/Cas9 knockout fibroblasts; 3D hydrogel triculture model with perlecan, PCa cells, macrophages, and fibroblasts; PCa tumoroid growth assay; primary tissue validation","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO in physiologically relevant 3D model; tissue validation; single lab","pmids":["32413029"],"is_preprint":false},{"year":2024,"finding":"SULF1 catalyzes the release of TGF-β1 from TGFBR3 (betaglycan) on the surface of gastric cancer cells; cancer-associated fibroblast-secreted SULF1 binds TGFBR3 and thereby activates TGF-β1/SMAD signaling, promoting metastasis and cisplatin resistance; TGF-β1 in turn induces SULF1 expression through the TGF-β1/SMAD pathway, forming a positive feedback loop.","method":"Co-immunoprecipitation of SULF1 with TGFBR3; CRISPR/Cas9 and siRNA knockdown; Western blot for SMAD signaling; migration/invasion assays; xenograft models; TGFβ pathway inhibitors","journal":"Cell death discovery","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP identifies SULF1-TGFBR3 interaction; multiple functional and signaling readouts; single lab","pmids":["38438372"],"is_preprint":false},{"year":2024,"finding":"SULF1 promotes pulmonary fibrosis through the TGF-β1/SMAD pathway; TGF-β1 induces SULF1 expression in fibroblasts; SULF1 knockdown suppresses fibroblast activation, proliferation, migration, and invasion under TGF-β1-driven and non-TGF-β1 conditions; SULF1 catalyzes release of TGF-β1 bound to TGFβRIII (TGFBR3), activating SMAD signaling.","method":"Co-immunoprecipitation; lentiviral shRNA knockdown; Western blot; ELISA; functional fibroblast assays; transcriptome sequencing of IPF patient samples","journal":"Journal of translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP identifies SULF1-TGFBR3 interaction; lentiviral KD with multiple functional readouts; transcriptomic patient data; single lab","pmids":["39354547"],"is_preprint":false},{"year":2025,"finding":"SULF1 enzymatic activity requires co-expression of sulfatase-modifying factor 1 (SUMF1) which converts the active-site cysteine to Cα-formylglycine (FGly); SULF1 activity also requires a Ca²⁺ ion; a marine fucosylated chondroitin sulfate inhibits SULF1 with IC50 ~0.05–0.07 μg/mL through mixed-mode inhibition.","method":"Recombinant SULF1 expression in HEK293F/T; co-expression with SUMF1; Ni²⁺-affinity purification; enzymatic activity assays; kinetic inhibition analysis; active site cysteine-to-FGly conversion verification","journal":"Glycobiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct biochemical reconstitution of enzymatic activation mechanism; active site modification confirmed; kinetics of inhibition characterized; rigorous in vitro enzymatic study","pmids":["41025518"],"is_preprint":false},{"year":2026,"finding":"CAF-derived SULF1 is required for cancer cell invasion in HNSCC: CRISPR/Cas9-knockout of SULF1 in primary CAFs reduces fibroblast proliferation and markedly impairs Cal33 cancer cell migration and invasion in vitro and in 3D spheroid cocultures; SULF2 from tumor cells does not compensate for SULF1 loss.","method":"CRISPR/Cas9 SULF1 knockout in primary CAFs; transwell migration/invasion assays; two-photon microscopy in 3D spheroid cocultures; proteomics confirming SULF1 absence and no SULF2 compensation","journal":"Cancer medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPR KO with 3D coculture model and proteomics; non-redundancy with SULF2 established; single lab","pmids":["41549062"],"is_preprint":false},{"year":2026,"finding":"JOSD1 deubiquitinase stabilizes SULF1 protein; stabilized SULF1 directly binds Frizzled-1 (FZD1) and facilitates Wnt7B-FZD1 complex formation, activating canonical Wnt/β-catenin signaling and inducing β-catenin nuclear accumulation in gastric cancer; JOSD1 oncogenic effects are strictly dependent on SULF1 stabilization.","method":"Co-immunoprecipitation; ubiquitination assays; rescue experiments; Western blot; β-catenin nuclear translocation assay; xenograft models","journal":"Translational oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP identifies SULF1-FZD1 interaction and JOSD1-SULF1 interaction; ubiquitination assays; rescue experiments; single lab","pmids":["42140034"],"is_preprint":false},{"year":2026,"finding":"Sulf1 knockout in the nucleus accumbens D1- or D2-receptor-expressing medium spiny neurons causes cell-type-specific electrophysiological defects: D2-MSNs show reduced rheobase with blunted firing at larger currents; D1-MSNs show more depolarized resting potential and increased AMPA/NMDA ratio; Sulf1 KO impairs reward learning (via D1 pathway) and aversion learning (via D2 pathway) in mice.","method":"Conditional Sulf1 KO using Drd1-Cre and Drd2-Cre; whole-cell patch-clamp recording; behavioral tests (CPP, inhibitory avoidance); CRISPR-Cas9 floxed mouse generation","journal":"Journal of neurochemistry / eNeuro","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-type-specific conditional KO with electrophysiology and behavioral validation; two papers from same group with convergent findings","pmids":["41486756","41381361"],"is_preprint":false}],"current_model":"SULF1 is a cell-surface and secreted 6-O-endosulfatase whose unique hydrophilic domain (HD) binds heparan sulfate chains with nanomolar affinity via a catch-bond mechanism dependent on 6-O-sulfate groups, and whose active-site cysteine must be converted to Cα-formylglycine by SUMF1 for enzymatic activity; by selectively removing 6-O-sulfate from N,6-O,2-O-trisulfated heparan sulfate on HSPGs, SULF1 modulates the availability and receptor presentation of heparin-binding growth factors (FGF-2, HGF, HB-EGF, VEGF165, GDNF) and morphogens (Wnt, Shh, Slit2, BMP, PDGF), with context-dependent consequences that include attenuation of receptor tyrosine kinase (FGFR, EGFR, c-Met, VEGFR-2) and downstream ERK/AKT/STAT3/Wnt/β-catenin signaling, shaping of morphogen gradients (Shh, Wnt, Slit2), axon guidance, and organ development; SULF1 gene expression is regulated by epigenetic silencing (CpG methylation, histone H3 methylation), transcriptional repression by vHNF1, hypoxia-driven HIF-α binding to promoter HREs, TNF-α/NF-κB induction, and post-translational stabilization by the deubiquitinase JOSD1, while a naturally occurring short splice isoform (SULF1B) and catalytically inactive short splice variants can antagonize or bypass full-length SULF1 function."},"narrative":{"mechanistic_narrative":"SULF1 is a cell-surface and secreted heparan sulfate 6-O-endosulfatase that remodels the sulfation landscape of heparan sulfate proteoglycans (HSPGs) to control the bioavailability and receptor presentation of heparin-binding growth factors and morphogens [PMID:12686563, PMID:19822709]. It selectively hydrolyzes 6-O-sulfate groups from the N,6-O,2-O-trisulfated disaccharides of intact cell-surface and matrix heparan sulfate, and is the dominant in vivo regulator of HS 6-O-desulfation, with substrate specificity for HS over chondroitin sulfate [PMID:19822709, PMID:22298771]. Enzymatic competence depends on a unique ~320-residue hydrophilic domain (HD) that confers nanomolar, 6-O-sulfate-dependent heparan sulfate binding through a catch-bond whose lifetime increases under force only on sulfated substrate, allowing processive action and substrate-turnover-driven release along HS chains [PMID:19666466, PMID:23891937, PMID:25863062]; activity additionally requires N-linked glycosylation, a Ca2+ ion, and SUMF1-mediated conversion of the active-site cysteine to Cα-formylglycine [PMID:17855356, PMID:41025518]. By stripping 6-O-sulfate from HSPGs, SULF1 attenuates ternary growth-factor/receptor/HS complex formation and downstream signaling for FGF-2/FGFR, HB-EGF and amphiregulin/EGFR, HGF/c-Met, and VEGF165/VEGFR-2, while conversely enhancing GDNF signaling by releasing GDNF from HS [PMID:12686563, PMID:14973553, PMID:16778174, PMID:17363371, PMID:21853101, PMID:17720696]. In development it shapes morphogen gradients and tissue patterning—restricting Shh diffusion in the neural tube, exerting ligand-specific control over canonical versus non-canonical Wnt signaling, regulating BMP-dependent somitogenesis and VEGFA-driven arterial specification, and guiding corticospinal axons by limiting Slit2 accumulation [PMID:24768893, PMID:25681501, PMID:23583585, PMID:23959107, PMID:29062064]. SULF1 acts as a context-dependent tumor suppressor whose loss enhances ERK/AKT-driven proliferation, anti-apoptotic and metabolic reprogramming (HB-EGF→ERK→c-Myc-driven glycolysis, ERK→Bim suppression) and cisplatin resistance, and its expression is controlled by CpG and histone methylation, vHNF1 repression, hypoxia-driven HIF binding, TNF-α/NF-κB induction, and JOSD1-mediated protein stabilization [PMID:12686563, PMID:24596063, PMID:26378042, PMID:17310998, PMID:19487294, PMID:21266348, PMID:42140034]. Haploinsufficiency of SULF1 is implicated in mesomelia-synostoses syndrome, a skeletal dysplasia [PMID:20602915].","teleology":[{"year":2003,"claim":"Established the founding biochemical activity—that SULF1 is a cell-surface HS 6-O-endosulfatase whose desulfation activity directly dampens growth-factor-driven RTK signaling—answering what this enzyme does to HSPGs and downstream pathways.","evidence":"Re-expression of HSulf-1 in ovarian cancer lines with sulfation, RTK phosphorylation, and ERK readouts","pmids":["12686563"],"confidence":"High","gaps":["Did not resolve the precise disaccharide substrate","Catch-bond/processivity mechanism unknown at this stage"]},{"year":2004,"claim":"Extended the desulfation-attenuates-signaling logic to the HGF/c-Met axis, showing SULF1 suppresses tumor cell motility and invasion, broadening the set of regulated growth-factor pathways.","evidence":"Stable HSulf-1 transfection in SCCHN cells with RTK phosphorylation, invasion, and proliferation assays","pmids":["14973553"],"confidence":"High","gaps":["In vivo relevance not tested here","Direct effect on HGF-HS binding not measured"]},{"year":2005,"claim":"Demonstrated SULF1 acts as a tumor suppressor in vivo and that its sulfatase activity is spatially restricted to the local cell surface, addressing where the enzyme operates.","evidence":"Myeloma cDNA transfection with SCID xenografts and ECM histology","pmids":["16192265"],"confidence":"Medium","gaps":["Single lab","Mechanism of ECM deposition not defined"]},{"year":2006,"claim":"Showed SULF1 controls angiogenesis by blocking assembly of the FGF-2/FGFR1c/HS ternary complex, with HS-independent VEGF121 as a negative control establishing sulfation-dependence.","evidence":"Breast xenografts, Matrigel plug, HUVEC knockdown, and Co-IP of the ternary complex","pmids":["16778174"],"confidence":"High","gaps":["Did not resolve which HSPG core proteins are key in endothelium"]},{"year":2007,"claim":"Defined the in vivo developmental role and substrate-bidirectionality—SULF1/2 are the major HS 6-O-desulfators and can enhance (rather than only attenuate) signaling by releasing GDNF from HS to drive esophageal innervation.","evidence":"Sulf1/Sulf2 double-knockout mice with HS desulfation assays, GDNF binding, neurite sprouting, and organ function tests","pmids":["17720696"],"confidence":"High","gaps":["Individual contributions of Sulf1 vs Sulf2 not separated","Mechanism of GDNF release vs FGF attenuation contrast not fully reconciled"]},{"year":2007,"claim":"Identified epigenetic silencing (CpG and histone H3 methylation) as a mechanism of SULF1 loss in cancer, explaining how its tumor-suppressor function is inactivated.","evidence":"Bisulfite sequencing, ChIP for H3 methylation, and 5-aza-dC restoration in ovarian cancer","pmids":["17310998"],"confidence":"Medium","gaps":["Upstream trigger of methylation unknown","Single lab"]},{"year":2007,"claim":"Linked SULF1 to autocrine EGFR signaling and cell-cycle control via amphiregulin/HB-EGF and cyclin D1, and established that N-linked glycosylation is essential for enzymatic activity, secretion, and HS binding.","evidence":"shRNA, neutralizing antibodies, ERK/cyclin D1 readouts; glycosylation/N-glycanase studies on quail Sulf1 ortholog","pmids":["17363371","17855356"],"confidence":"Medium","gaps":["Glycosylation site mapping incomplete","EGFR-ligand studies in single lab"]},{"year":2009,"claim":"Mapped the unique hydrophilic domain as the high-affinity, 6-O-sulfate-dependent HS-interaction module required for activity, and showed substrate turnover facilitates enzyme release—an early model for processivity.","evidence":"HD deletion mutants, GST-HD fusions, SPR, and FGF-2 signaling assays","pmids":["19666466"],"confidence":"High","gaps":["Single-molecule kinetics not yet measured","Structure of HD-HS interface unresolved"]},{"year":2009,"claim":"Defined the precise substrate (N,6-O,2-O-trisulfated disaccharides) and a pharmacological inhibitor (PI-88), and identified vHNF1 repression and promoter hypermethylation as transcriptional/epigenetic regulators of SULF1.","evidence":"Flow cytometry with RB4CD12 antibody, disaccharide analysis, PI-88 inhibition; ChIP/reporter for vHNF1; bisulfite sequencing in breast/gastric cancer","pmids":["19822709","19487294","19006069"],"confidence":"High","gaps":["Catalytic mechanism on intact chains not structurally resolved","Regulator hierarchy across tissues unknown"]},{"year":2010,"claim":"Connected SULF1 to human Mendelian disease, implicating haploinsufficiency in mesomelia-synostoses syndrome and identifying skeletal/cartilage tissues as high-expression sites.","evidence":"Array CGH and breakpoint sequencing in MSS patients with qRT-PCR tissue profiling","pmids":["20602915"],"confidence":"Medium","gaps":["Causation by deletion alone not proven (contiguous genes possible)","Skeletal HS-substrate mechanism not defined"]},{"year":2011,"claim":"Showed hypoxia represses SULF1 via HIF-1α/HIF-2α binding to promoter HREs, releasing FGF2/FGFR2 signaling and invasion, and that SULF1 downregulates VEGFR-2 phosphorylation to inhibit angiogenesis—integrating SULF1 into the tumor microenvironment.","evidence":"ChIP with HIF antibodies, HIF-1α shRNA rescue, FGFR2 depletion; gain/loss-of-function with p-VEGFR-2 and microvessel density","pmids":["21266348","21853101"],"confidence":"High","gaps":["VEGFR-2 study single lab","Crosstalk between hypoxia repression and other regulators not integrated"]},{"year":2012,"claim":"Quantified Sulf1's distinct, organ-specific in vivo impact on HS sulfation (greater than Sulf2 despite lower mRNA) with specificity for HS over chondroitin sulfate, and showed SULF1 selectively blocks cell-surface HS-dependent Wnt/β-catenin signaling.","evidence":"Disaccharide analysis across 8 organs in Sulf1/Sulf2 KO mice; TCF/LEF reporter, Wnt3a rescue, and β-catenin shRNA in gastric cancer lines","pmids":["22298771","21722266"],"confidence":"High","gaps":["Wnt study limited to two cell lines, single lab","Basis for Sulf1>Sulf2 potency not explained"]},{"year":2013,"claim":"Resolved the biophysical basis of HD-HS engagement—two binding sites and a single-molecule off-rate ~500-fold higher than SPR, supporting processive action—and showed conserved Wnt/Wingless control across orthologs plus BMP/FGF roles in somitogenesis.","evidence":"AFM force spectroscopy and HD subdomain mapping; Drosophila Wg stability assays with human SULF1 cross-rescue; zebrafish morpholino with BMP/FGF epistasis","pmids":["23891937","23300081","23583585"],"confidence":"Medium","gaps":["Wg-degradation mechanism not molecularly resolved","Zebrafish/Drosophila ortholog findings need vertebrate confirmation"]},{"year":2014,"claim":"Established SULF1 as a morphogen-gradient shaper (restricting Shh diffusion, regulating VEGFA165 arterial specification) and detailed a tumor-suppressor mechanism in which SULF1 loss elevates p-ERK to suppress proapoptotic Bim.","evidence":"GFP-Shh imaging in Xenopus, sulf1 morphant rescue in zebrafish; ERK/PI3K inhibitor epistasis and Bim rescue with xenografts","pmids":["24768893","23959107","24596063"],"confidence":"Medium","gaps":["Morphogen studies in non-mammalian models","Bim/ERK link from single lab"]},{"year":2015,"claim":"Defined the molecular catch-bond mechanism (force-prolonged lifetime on 6-O-sulfated HS, slip-bond when desulfated; ΔE≈9 kBT, Δx≈3.2 nm) and broadened SULF1 functions to metabolic reprogramming, neuronal HS biology, and ligand-specific Wnt control.","evidence":"AFM force-clamp/dynamic spectroscopy with two-state model; isotope-tracer metabolomics in ovarian cancer; Sulf1-KO cerebellar granule cell assays; tagged-Wnt Xenopus explants","pmids":["25863062","26378042","26448642","25681501"],"confidence":"Medium","gaps":["Structural basis of catch bond not crystallographically defined","Tissue-specific signaling outcomes from single labs"]},{"year":2016,"claim":"Identified TNF-α/NF-κB/MAPK as an inflammatory inducer of secreted, catalytically active SULF1 that dampens FGF-1 signaling, integrating SULF1 into inflammatory regulation.","evidence":"TNF-α treatment of MRC-5 fibroblasts with pathway inhibitors, HS disaccharide analysis, and siRNA rescue","pmids":["27693418"],"confidence":"Medium","gaps":["Single cell type","In vivo inflammatory relevance not tested"]},{"year":2017,"claim":"Demonstrated SULF1/2 are required for corticospinal axon guidance by limiting Slit2 accumulation, with unbiased proteomics identifying Slit2 as the mediator and in utero rescue confirming causation.","evidence":"Sulf1/Sulf2 DKO mice, in utero electroporation rescue, proteomics, and CST tract tracing","pmids":["29062064"],"confidence":"High","gaps":["Sulf1 vs Sulf2 individual contributions not separated","Direct Slit2-HS biochemistry not shown"]},{"year":2019,"claim":"Confirmed via unbiased genome-scale screening that SULF1 loss contributes to cisplatin resistance, corroborating earlier mechanistic links.","evidence":"GeCKO CRISPR knockout screen in ovarian cancer with CCK-8 and RT-PCR validation","pmids":["31218106"],"confidence":"Medium","gaps":["Resistance mechanism downstream of SULF1 loss not dissected here"]},{"year":2020,"claim":"Showed stromal (fibroblast-derived) SULF1 acts non-cell-autonomously to suppress Wnt3A-driven prostate cancer growth in a perlecan-containing 3D model, with macrophage regulation of SULF1/HSPG2 levels.","evidence":"CRISPR-KO fibroblasts in a 3D hydrogel triculture with tumoroid growth and tissue validation","pmids":["32413029"],"confidence":"Medium","gaps":["Single lab","Molecular basis of macrophage induction not defined"]},{"year":2024,"claim":"Identified a TGFBR3 (betaglycan)-dependent activity in which SULF1 releases bound TGF-β1 to activate SMAD signaling, creating a TGF-β1/SMAD positive-feedback loop driving cancer metastasis, cisplatin resistance, and pulmonary fibrosis.","evidence":"Co-IP of SULF1-TGFBR3, CRISPR/shRNA knockdown, SMAD readouts, xenografts (gastric cancer); Co-IP, shRNA, and IPF transcriptomics (lung fibrosis)","pmids":["38438372","39354547"],"confidence":"Medium","gaps":["Whether TGF-β1 release is sulfatase-dependent or binding-dependent not fully resolved","Co-IP without structural mapping of SULF1-TGFBR3 interface"]},{"year":2025,"claim":"Reconstituted the SULF1 activation mechanism in vitro—SUMF1-mediated cysteine-to-formylglycine conversion plus a required Ca2+ ion—and characterized a fucosylated chondroitin sulfate as a mixed-mode inhibitor.","evidence":"Recombinant SULF1/SUMF1 co-expression, Ni-affinity purification, FGly conversion verification, and inhibition kinetics","pmids":["41025518"],"confidence":"High","gaps":["No crystal/cryo-EM structure of activated enzyme","Inhibitor selectivity over SULF2 not established"]},{"year":2026,"claim":"Established SULF1 as a regulated protein target—JOSD1 deubiquitinase stabilizes SULF1, which then binds FZD1 to promote Wnt7B/FZD1 complex and β-catenin signaling—and confirmed non-redundant stromal SULF1 requirement for HNSCC invasion.","evidence":"Co-IP, ubiquitination and rescue assays, β-catenin translocation, xenografts (gastric cancer); CRISPR-KO in primary CAFs with 3D coculture and proteomics (HNSCC)","pmids":["42140034","41549062"],"confidence":"Medium","gaps":["FZD1-promoting Wnt activity contrasts with prior Wnt-inhibitory findings; context dependence unresolved","Single labs"]},{"year":2026,"claim":"Revealed a cell-type-specific neuronal role: Sulf1 shapes intrinsic and synaptic properties of D1- and D2-MSNs in the nucleus accumbens and is required for reward and aversion learning.","evidence":"Conditional Sulf1 KO with Drd1-/Drd2-Cre, whole-cell patch-clamp, and behavioral assays","pmids":["41486756","41381361"],"confidence":"Medium","gaps":["HS-substrate or growth-factor pathway underlying MSN phenotype not identified","Same group, convergent but not independently replicated"]},{"year":null,"claim":"How SULF1's bidirectional context-dependent effects on Wnt signaling (inhibitory cell-surface block versus FZD1-promoting complex formation) are reconciled, and the atomic structure of the activated HD-HS catch-bond interface, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No high-resolution structure of SULF1 or the HD-HS complex","Determinants of attenuating vs enhancing signaling outcomes not defined","Mechanistic basis for Sulf1/Sulf2 non-redundancy unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,10,16,34]},{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[0,10,16]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[9,18,24]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,3,5,32]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,10]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[2,28]},{"term_id":"GO:0031012","term_label":"extracellular matrix","supporting_discovery_ids":[2,10]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,3,17,32]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[5,20,21,22,29]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[13,23,27,30,32]},{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[2,10]}],"complexes":[],"partners":["TGFBR3","FZD1","JOSD1","SUMF1","FGFR1","FGFR2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8IWU6","full_name":"Extracellular sulfatase Sulf-1","aliases":["Arylsulfatase","N-acetylglucosamine-6-sulfatase"],"length_aa":871,"mass_kda":101.0,"function":"Exhibits arylsulfatase activity and highly specific endoglucosamine-6-sulfatase activity (PubMed:12368295, PubMed:12686563). It can remove sulfate from the C-6 position of glucosamine within specific subregions of intact heparin (PubMed:12368295, PubMed:12686563). Diminishes HSPG (heparan sulfate proteoglycans) sulfation, inhibits signaling by heparin-dependent growth factors, diminishes proliferation, and facilitates apoptosis in response to exogenous stimulation (PubMed:12686563)","subcellular_location":"Secreted","url":"https://www.uniprot.org/uniprotkb/Q8IWU6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SULF1","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/SULF1","total_profiled":1310},"omim":[{"mim_id":"621228","title":"LONG INTERGENIC NONCODING RNA 1013; LINC01013","url":"https://www.omim.org/entry/621228"},{"mim_id":"613543","title":"SOLUTE CARRIER ORGANIC ANION TRANSPORTER FAMILY, MEMBER 5A1; SLCO5A1","url":"https://www.omim.org/entry/613543"},{"mim_id":"610013","title":"SULFATASE 2; SULF2","url":"https://www.omim.org/entry/610013"},{"mim_id":"610012","title":"SULFATASE 1; SULF1","url":"https://www.omim.org/entry/610012"},{"mim_id":"607102","title":"WT1 TRANSCRIPTION FACTOR; WT1","url":"https://www.omim.org/entry/607102"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"blood vessel","ntpm":112.2}],"url":"https://www.proteinatlas.org/search/SULF1"},"hgnc":{"alias_symbol":["KIAA1077","SULF-1","hSulf-1"],"prev_symbol":[]},"alphafold":{"accession":"Q8IWU6","domains":[{"cath_id":"3.40.720.10","chopping":"40-391_407-414","consensus_level":"high","plddt":95.3084,"start":40,"end":414},{"cath_id":"-","chopping":"775-832","consensus_level":"medium","plddt":95.0052,"start":775,"end":832}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8IWU6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8IWU6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8IWU6-F1-predicted_aligned_error_v6.png","plddt_mean":74.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SULF1","jax_strain_url":"https://www.jax.org/strain/search?query=SULF1"},"sequence":{"accession":"Q8IWU6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8IWU6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8IWU6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8IWU6"}},"corpus_meta":[{"pmid":"12686563","id":"PMC_12686563","title":"Loss of HSulf-1 up-regulates heparin-binding growth factor signaling in cancer.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12686563","citation_count":204,"is_preprint":false},{"pmid":"23684551","id":"PMC_23684551","title":"MicroRNA-21 suppresses PTEN and hSulf-1 expression and promotes hepatocellular carcinoma progression through AKT/ERK pathways.","date":"2013","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/23684551","citation_count":159,"is_preprint":false},{"pmid":"17720696","id":"PMC_17720696","title":"SULF1 and SULF2 regulate heparan sulfate-mediated GDNF signaling for esophageal innervation.","date":"2007","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/17720696","citation_count":144,"is_preprint":false},{"pmid":"16778174","id":"PMC_16778174","title":"HSulf-1 inhibits angiogenesis and tumorigenesis in vivo.","date":"2006","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/16778174","citation_count":122,"is_preprint":false},{"pmid":"16192265","id":"PMC_16192265","title":"HSulf-1 and HSulf-2 are potent inhibitors of myeloma tumor growth in vivo.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16192265","citation_count":117,"is_preprint":false},{"pmid":"14973553","id":"PMC_14973553","title":"HSulf-1 modulates HGF-mediated tumor cell invasion and signaling in head and neck squamous carcinoma.","date":"2004","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/14973553","citation_count":117,"is_preprint":false},{"pmid":"17593974","id":"PMC_17593974","title":"Secreted sulfatases Sulf1 and Sulf2 have overlapping yet essential roles in mouse neonatal survival.","date":"2007","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/17593974","citation_count":101,"is_preprint":false},{"pmid":"17310998","id":"PMC_17310998","title":"Epigenetic silencing of HSulf-1 in ovarian cancer:implications in chemoresistance.","date":"2007","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/17310998","citation_count":94,"is_preprint":false},{"pmid":"19373441","id":"PMC_19373441","title":"The tumor suppressor function of human sulfatase 1 (SULF1) in carcinogenesis.","date":"2009","source":"Journal of gastrointestinal cancer","url":"https://pubmed.ncbi.nlm.nih.gov/19373441","citation_count":81,"is_preprint":false},{"pmid":"15817123","id":"PMC_15817123","title":"Enhanced levels of Hsulf-1 interfere with heparin-binding growth factor signaling in pancreatic cancer.","date":"2005","source":"Molecular cancer","url":"https://pubmed.ncbi.nlm.nih.gov/15817123","citation_count":78,"is_preprint":false},{"pmid":"18213582","id":"PMC_18213582","title":"Redundant function of the heparan sulfate 6-O-endosulfatases Sulf1 and Sulf2 during skeletal development.","date":"2008","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/18213582","citation_count":77,"is_preprint":false},{"pmid":"19822709","id":"PMC_19822709","title":"Direct detection of HSulf-1 and HSulf-2 activities on extracellular heparan sulfate and their inhibition by PI-88.","date":"2009","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/19822709","citation_count":75,"is_preprint":false},{"pmid":"22298771","id":"PMC_22298771","title":"Organ-specific sulfation patterns of heparan sulfate generated by extracellular sulfatases Sulf1 and Sulf2 in mice.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/22298771","citation_count":72,"is_preprint":false},{"pmid":"19666466","id":"PMC_19666466","title":"Characterization of the human sulfatase Sulf1 and its high affinity heparin/heparan sulfate interaction domain.","date":"2009","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19666466","citation_count":65,"is_preprint":false},{"pmid":"17363371","id":"PMC_17363371","title":"Loss of HSulf-1 expression enhances autocrine signaling mediated by amphiregulin in breast cancer.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17363371","citation_count":64,"is_preprint":false},{"pmid":"16762634","id":"PMC_16762634","title":"SULF1 inhibits tumor growth and potentiates the effects of histone deacetylase inhibitors in hepatocellular carcinoma.","date":"2006","source":"Gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/16762634","citation_count":63,"is_preprint":false},{"pmid":"21228115","id":"PMC_21228115","title":"Identification of MST1/STK4 and SULF1 proteins as autoantibody targets for the diagnosis of colorectal cancer by using phage microarrays.","date":"2011","source":"Molecular & cellular proteomics : MCP","url":"https://pubmed.ncbi.nlm.nih.gov/21228115","citation_count":59,"is_preprint":false},{"pmid":"18507859","id":"PMC_18507859","title":"Expression of novel extracellular sulfatases Sulf-1 and Sulf-2 in normal and osteoarthritic articular cartilage.","date":"2008","source":"Arthritis research & therapy","url":"https://pubmed.ncbi.nlm.nih.gov/18507859","citation_count":55,"is_preprint":false},{"pmid":"21266348","id":"PMC_21266348","title":"HSulf-1 modulates FGF2- and hypoxia-mediated migration and invasion of breast cancer cells.","date":"2011","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/21266348","citation_count":50,"is_preprint":false},{"pmid":"19006069","id":"PMC_19006069","title":"Promoter hypermethylation correlates with the Hsulf-1 silencing in human breast and gastric cancer.","date":"2009","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/19006069","citation_count":43,"is_preprint":false},{"pmid":"20602915","id":"PMC_20602915","title":"Mesomelia-synostoses syndrome results from deletion of SULF1 and SLCO5A1 genes at 8q13.","date":"2010","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/20602915","citation_count":42,"is_preprint":false},{"pmid":"26448642","id":"PMC_26448642","title":"Sulf1 and Sulf2 Differentially Modulate Heparan Sulfate Proteoglycan Sulfation during Postnatal Cerebellum Development: Evidence for Neuroprotective and Neurite Outgrowth Promoting Functions.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/26448642","citation_count":41,"is_preprint":false},{"pmid":"19487294","id":"PMC_19487294","title":"Regulation of HSulf-1 expression by variant hepatic nuclear factor 1 in ovarian cancer.","date":"2009","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/19487294","citation_count":39,"is_preprint":false},{"pmid":"31218106","id":"PMC_31218106","title":"Loss of ZNF587B and SULF1 contributed to cisplatin resistance in ovarian cancer cell lines based on Genome-scale CRISPR/Cas9 screening.","date":"2019","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/31218106","citation_count":37,"is_preprint":false},{"pmid":"19577565","id":"PMC_19577565","title":"A novel SULF1 splice variant inhibits Wnt signalling but enhances angiogenesis by opposing SULF1 activity.","date":"2009","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/19577565","citation_count":33,"is_preprint":false},{"pmid":"16603650","id":"PMC_16603650","title":"Hsulf-1 regulates growth and invasion of pancreatic cancer cells.","date":"2006","source":"Journal of clinical pathology","url":"https://pubmed.ncbi.nlm.nih.gov/16603650","citation_count":30,"is_preprint":false},{"pmid":"22873647","id":"PMC_22873647","title":"HSULF-1 inhibits ERK and AKT signaling and decreases cell viability in vitro in human lung epithelial cells.","date":"2012","source":"Respiratory research","url":"https://pubmed.ncbi.nlm.nih.gov/22873647","citation_count":30,"is_preprint":false},{"pmid":"25225614","id":"PMC_25225614","title":"Loss of HSulf-1 promotes altered lipid metabolism in ovarian cancer.","date":"2014","source":"Cancer & metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/25225614","citation_count":29,"is_preprint":false},{"pmid":"17855356","id":"PMC_17855356","title":"Quail Sulf1 function requires asparagine-linked glycosylation.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17855356","citation_count":28,"is_preprint":false},{"pmid":"21722266","id":"PMC_21722266","title":"HSulf-1 inhibits cell proliferation and invasion in human gastric cancer.","date":"2011","source":"Cancer science","url":"https://pubmed.ncbi.nlm.nih.gov/21722266","citation_count":26,"is_preprint":false},{"pmid":"26378042","id":"PMC_26378042","title":"HSulf-1 deficiency dictates a metabolic reprograming of glycolysis and TCA cycle in ovarian cancer.","date":"2015","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/26378042","citation_count":26,"is_preprint":false},{"pmid":"17061267","id":"PMC_17061267","title":"Sulf1 expression pattern and its role in cartilage and joint development.","date":"2006","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/17061267","citation_count":26,"is_preprint":false},{"pmid":"32432744","id":"PMC_32432744","title":"LncRNA NEAT1 regulated cell proliferation, invasion, migration and apoptosis by targeting has-miR-376b-3p/SULF1 axis in non-small cell lung cancer.","date":"2020","source":"European review for medical and pharmacological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/32432744","citation_count":26,"is_preprint":false},{"pmid":"21853101","id":"PMC_21853101","title":"hSulf-1 gene exhibits anticancer efficacy through negatively regulating VEGFR-2 signaling in human cancers.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21853101","citation_count":24,"is_preprint":false},{"pmid":"23300081","id":"PMC_23300081","title":"Drosophila heparan sulfate 6-O-endosulfatase Sulf1 facilitates wingless (Wg) protein degradation.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23300081","citation_count":24,"is_preprint":false},{"pmid":"26764203","id":"PMC_26764203","title":"Heparan sulfate 6-O-endosulfatases, Sulf1 and Sulf2, regulate glomerular integrity by modulating growth factor signaling.","date":"2016","source":"American journal of physiology. Renal physiology","url":"https://pubmed.ncbi.nlm.nih.gov/26764203","citation_count":23,"is_preprint":false},{"pmid":"25681501","id":"PMC_25681501","title":"Sulf1 has ligand-dependent effects on canonical and non-canonical Wnt signalling.","date":"2015","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/25681501","citation_count":23,"is_preprint":false},{"pmid":"32413029","id":"PMC_32413029","title":"SULF1 suppresses Wnt3A-driven growth of bone metastatic prostate cancer in perlecan-modified 3D cancer-stroma-macrophage triculture models.","date":"2020","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/32413029","citation_count":22,"is_preprint":false},{"pmid":"22700218","id":"PMC_22700218","title":"Mammalian Sulf1 RNA alternative splicing and its significance to tumour growth regulation.","date":"2012","source":"Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/22700218","citation_count":22,"is_preprint":false},{"pmid":"23583585","id":"PMC_23583585","title":"Sulf1 modulates BMP signaling and is required for somite morphogenesis and development of the horizontal myoseptum.","date":"2013","source":"Developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/23583585","citation_count":22,"is_preprint":false},{"pmid":"24768893","id":"PMC_24768893","title":"Sulf1 influences the Shh morphogen gradient during the dorsal ventral patterning of the neural tube in Xenopus tropicalis.","date":"2014","source":"Developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/24768893","citation_count":22,"is_preprint":false},{"pmid":"27888216","id":"PMC_27888216","title":"Drosophila Sulf1 is required for the termination of intestinal stem cell division during regeneration.","date":"2016","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/27888216","citation_count":22,"is_preprint":false},{"pmid":"26464246","id":"PMC_26464246","title":"Expression of Sulf1 and Sulf2 in cartilage, bone and endochondral fracture healing.","date":"2015","source":"Histochemistry and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/26464246","citation_count":21,"is_preprint":false},{"pmid":"22825572","id":"PMC_22825572","title":"The enhanced antitumor effects of biodegradable cationic heparin-polyethyleneimine nanogels delivering HSulf-1 gene combined with cisplatin on ovarian cancer.","date":"2012","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/22825572","citation_count":21,"is_preprint":false},{"pmid":"36428645","id":"PMC_36428645","title":"Extracellular Heparan 6-O-Endosulfatases SULF1 and SULF2 in Head and Neck Squamous Cell Carcinoma and Other Malignancies.","date":"2022","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/36428645","citation_count":21,"is_preprint":false},{"pmid":"38438372","id":"PMC_38438372","title":"Cancer associated fibroblasts-derived SULF1 promotes gastric cancer metastasis and CDDP resistance through the TGFBR3-mediated TGF-β signaling pathway.","date":"2024","source":"Cell death discovery","url":"https://pubmed.ncbi.nlm.nih.gov/38438372","citation_count":21,"is_preprint":false},{"pmid":"25863062","id":"PMC_25863062","title":"Catch bond interaction between cell-surface sulfatase Sulf1 and glycosaminoglycans.","date":"2015","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/25863062","citation_count":21,"is_preprint":false},{"pmid":"21214932","id":"PMC_21214932","title":"Polymorphisms in the SULF1 gene are associated with early age of onset and survival of ovarian cancer.","date":"2011","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/21214932","citation_count":21,"is_preprint":false},{"pmid":"25448158","id":"PMC_25448158","title":"Sulf1 and Sulf2 expression in the nervous system and its role in limiting neurite outgrowth in vitro.","date":"2014","source":"Experimental neurology","url":"https://pubmed.ncbi.nlm.nih.gov/25448158","citation_count":18,"is_preprint":false},{"pmid":"24726914","id":"PMC_24726914","title":"SULF1/SULF2 splice variants differentially regulate pancreatic tumour growth progression.","date":"2014","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/24726914","citation_count":18,"is_preprint":false},{"pmid":"38760544","id":"PMC_38760544","title":"CircNSD1 promotes cardiac fibrosis through targeting the miR-429-3p/SULF1/Wnt/β-catenin signaling pathway.","date":"2024","source":"Acta pharmacologica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/38760544","citation_count":17,"is_preprint":false},{"pmid":"29062064","id":"PMC_29062064","title":"Desulfation of Heparan Sulfate by Sulf1 and Sulf2 Is Required for Corticospinal Tract Formation.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/29062064","citation_count":17,"is_preprint":false},{"pmid":"24596063","id":"PMC_24596063","title":"Loss of HSulf-1 expression enhances tumorigenicity by inhibiting Bim expression in ovarian cancer.","date":"2014","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/24596063","citation_count":16,"is_preprint":false},{"pmid":"27013228","id":"PMC_27013228","title":"SULF1/SULF2 reactivation during liver damage and tumour growth.","date":"2016","source":"Histochemistry and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/27013228","citation_count":16,"is_preprint":false},{"pmid":"23074159","id":"PMC_23074159","title":"Distinct expression patterns of Sulf1 and Hs6st1 spatially regulate heparan sulfate sulfation during prostate development.","date":"2012","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/23074159","citation_count":16,"is_preprint":false},{"pmid":"28169314","id":"PMC_28169314","title":"Loss of HSulf-1: The Missing Link between Autophagy and Lipid Droplets in Ovarian Cancer.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28169314","citation_count":15,"is_preprint":false},{"pmid":"24970807","id":"PMC_24970807","title":"Sulfatase 1 (hSulf-1) reverses basic fibroblast growth factor-stimulated signaling and inhibits growth of hepatocellular carcinoma in animal model.","date":"2014","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/24970807","citation_count":15,"is_preprint":false},{"pmid":"23959107","id":"PMC_23959107","title":"The heparan sulfate editing enzyme Sulf1 plays a novel role in zebrafish VegfA mediated arterial venous identity.","date":"2014","source":"Angiogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/23959107","citation_count":15,"is_preprint":false},{"pmid":"27693418","id":"PMC_27693418","title":"Tumour-necrosis factor-α induces heparan sulfate 6-O-endosulfatase 1 (Sulf-1) expression in fibroblasts.","date":"2016","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/27693418","citation_count":13,"is_preprint":false},{"pmid":"22086394","id":"PMC_22086394","title":"Efficient inhibition of an intraperitoneal xenograft model of human ovarian cancer by HSulf-1 gene delivered by biodegradable cationic heparin-polyethyleneimine nanogels.","date":"2011","source":"Oncology reports","url":"https://pubmed.ncbi.nlm.nih.gov/22086394","citation_count":13,"is_preprint":false},{"pmid":"23891937","id":"PMC_23891937","title":"Cooperation of binding sites at the hydrophilic domain of cell-surface sulfatase Sulf1 allows for dynamic interaction of the enzyme with its substrate heparan sulfate.","date":"2013","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/23891937","citation_count":13,"is_preprint":false},{"pmid":"32377705","id":"PMC_32377705","title":"HSulf‑1 and palbociclib exert synergistic antitumor effects on RB‑positive triple‑negative breast cancer.","date":"2020","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/32377705","citation_count":12,"is_preprint":false},{"pmid":"24322345","id":"PMC_24322345","title":"The association of arylendosulfatase 1 (SULF1) gene polymorphism with recurrent miscarriage.","date":"2013","source":"Journal of assisted reproduction and genetics","url":"https://pubmed.ncbi.nlm.nih.gov/24322345","citation_count":12,"is_preprint":false},{"pmid":"23053899","id":"PMC_23053899","title":"SULF1 inhibits proliferation and invasion of esophageal squamous cell carcinoma cells by decreasing heparin-binding growth factor signaling.","date":"2012","source":"Digestive diseases and sciences","url":"https://pubmed.ncbi.nlm.nih.gov/23053899","citation_count":11,"is_preprint":false},{"pmid":"30127996","id":"PMC_30127996","title":"Genetic variations in the SULF1 gene alter the risk of cervical cancer and precancerous lesions.","date":"2018","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/30127996","citation_count":11,"is_preprint":false},{"pmid":"25370455","id":"PMC_25370455","title":"Expression of the heparan sulfate 6-O-endosulfatases, Sulf1 and Sulf2, in the avian and mammalian inner ear suggests a role for sulfation during inner ear development.","date":"2014","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/25370455","citation_count":11,"is_preprint":false},{"pmid":"27294358","id":"PMC_27294358","title":"Short SULF1/SULF2 splice variants predominate in mammary tumours with a potential to facilitate receptor tyrosine kinase-mediated cell signalling.","date":"2016","source":"Histochemistry and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/27294358","citation_count":11,"is_preprint":false},{"pmid":"22848304","id":"PMC_22848304","title":"HSulf-1 suppresses cell growth and down-regulates Hedgehog signaling in human gastric cancer cells.","date":"2011","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/22848304","citation_count":10,"is_preprint":false},{"pmid":"39354547","id":"PMC_39354547","title":"SULF1 expression is increased and promotes fibrosis through the TGF-β1/SMAD pathway in idiopathic pulmonary fibrosis.","date":"2024","source":"Journal of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/39354547","citation_count":9,"is_preprint":false},{"pmid":"23480519","id":"PMC_23480519","title":"Endosulfatases SULF1 and SULF2 limit Chlamydia muridarum infection.","date":"2013","source":"Cellular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/23480519","citation_count":9,"is_preprint":false},{"pmid":"32038163","id":"PMC_32038163","title":"Abnormal Pyramidal Decussation and Bilateral Projection of the Corticospinal Tract Axons in Mice Lacking the Heparan Sulfate Endosulfatases, Sulf1 and Sulf2.","date":"2020","source":"Frontiers in molecular neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/32038163","citation_count":9,"is_preprint":false},{"pmid":"38844922","id":"PMC_38844922","title":"SULF1 regulates malignant progression of colorectal cancer by modulating ARSH via FAK/PI3K/AKT/mTOR signaling.","date":"2024","source":"Cancer cell international","url":"https://pubmed.ncbi.nlm.nih.gov/38844922","citation_count":8,"is_preprint":false},{"pmid":"26236329","id":"PMC_26236329","title":"Restoration of epigenetically silenced SULF1 expression by 5-aza-2-deoxycytidine sensitizes hepatocellular carcinoma cells to chemotherapy-induced apoptosis.","date":"2015","source":"Medical epigenetics","url":"https://pubmed.ncbi.nlm.nih.gov/26236329","citation_count":8,"is_preprint":false},{"pmid":"17905233","id":"PMC_17905233","title":"FGF mediated Sulf1 regulation.","date":"2007","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/17905233","citation_count":7,"is_preprint":false},{"pmid":"33276062","id":"PMC_33276062","title":"Development of novel monoclonal antibodies and immunoassays for sensitive and specific detection of SULF1 endosulfatase.","date":"2020","source":"Biochimica et biophysica acta. General subjects","url":"https://pubmed.ncbi.nlm.nih.gov/33276062","citation_count":7,"is_preprint":false},{"pmid":"24911625","id":"PMC_24911625","title":"Association of the SNP rs2623047 in the HSPG modification enzyme SULF1 with an Australian Caucasian breast cancer cohort.","date":"2014","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/24911625","citation_count":7,"is_preprint":false},{"pmid":"27274271","id":"PMC_27274271","title":"Single-nucleotide polymorphism in microRNA-binding site of SULF1 target gene as a protective factor against the susceptibility to breast cancer: a case-control study.","date":"2016","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/27274271","citation_count":7,"is_preprint":false},{"pmid":"37539927","id":"PMC_37539927","title":"SULF1 Activates the VEGFR2/PI3K/AKT Pathway to Promote the Development of Cervical Cancer.","date":"2024","source":"Current cancer drug targets","url":"https://pubmed.ncbi.nlm.nih.gov/37539927","citation_count":6,"is_preprint":false},{"pmid":"35409127","id":"PMC_35409127","title":"Context Dependent Sulf1/Sulf2 Functional Divergence in Endothelial Cell Activity.","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35409127","citation_count":6,"is_preprint":false},{"pmid":"24944651","id":"PMC_24944651","title":"hSulf-1 inhibits cell proliferation and migration and promotes apoptosis by suppressing stat3 signaling in hepatocellular carcinoma.","date":"2014","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/24944651","citation_count":5,"is_preprint":false},{"pmid":"19653319","id":"PMC_19653319","title":"Expression analysis of Sulf1 in the chick forebrain at early and late stages of development.","date":"2009","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/19653319","citation_count":5,"is_preprint":false},{"pmid":"31428635","id":"PMC_31428635","title":"Sulfatases, in Particular Sulf1, Are Important for the Integrity of the Glomerular Filtration Barrier in Zebrafish.","date":"2019","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/31428635","citation_count":5,"is_preprint":false},{"pmid":"29360432","id":"PMC_29360432","title":"Multi-tasking Sulf1/Sulf2 enzymes do not only facilitate extracellular cell signalling but also participate in cell cycle related nuclear events.","date":"2018","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/29360432","citation_count":4,"is_preprint":false},{"pmid":"37985153","id":"PMC_37985153","title":"[Identification of SULF1 as a Shared Gene in Idiopathic Pulmonary Fibrosis
and Lung Adenocarcinoma].","date":"2023","source":"Zhongguo fei ai za zhi = Chinese journal of lung cancer","url":"https://pubmed.ncbi.nlm.nih.gov/37985153","citation_count":3,"is_preprint":false},{"pmid":"34489650","id":"PMC_34489650","title":"Expression of Heparan Sulfate Endosulfatases in the Adult Mouse Brain: Co-expression of Sulf1 and Dopamine D1/D2 Receptors.","date":"2021","source":"Frontiers in neuroanatomy","url":"https://pubmed.ncbi.nlm.nih.gov/34489650","citation_count":3,"is_preprint":false},{"pmid":"36359323","id":"PMC_36359323","title":"Role of Prosaposin and Extracellular Sulfatase Sulf-1 Detection in Pleural Effusions as Diagnostic Biomarkers of Malignant Mesothelioma.","date":"2022","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/36359323","citation_count":2,"is_preprint":false},{"pmid":"26131010","id":"PMC_26131010","title":"SULF 1 gene polymorphism, rs6990375 is in significant association with fetus failure in IVF technique.","date":"2015","source":"Iranian journal of reproductive medicine","url":"https://pubmed.ncbi.nlm.nih.gov/26131010","citation_count":2,"is_preprint":false},{"pmid":"41549062","id":"PMC_41549062","title":"SULF1 in Cancer Associated Fibroblasts Promotes Invasion in Head and Neck Cancer Cell Lines.","date":"2026","source":"Cancer medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41549062","citation_count":1,"is_preprint":false},{"pmid":"39707607","id":"PMC_39707607","title":"Genetic variants of FER and SULF1 in the fibroblast-related genes are associated with non-small-cell lung cancer survival.","date":"2024","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/39707607","citation_count":1,"is_preprint":false},{"pmid":"38992676","id":"PMC_38992676","title":"Mesomelia-synostoses syndrome: contiguous deletion syndrome, SULF1 haploinsufficiency or enhancer adoption?","date":"2024","source":"Molecular cytogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/38992676","citation_count":1,"is_preprint":false},{"pmid":"41486756","id":"PMC_41486756","title":"Essential Roles of Heparan Sulfate Endosulfatase Sulf1 in Reward and Aversion Learning Through Distinct Dopamine D1 and D2 Receptor Pathways in Male Mice.","date":"2026","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/41486756","citation_count":1,"is_preprint":false},{"pmid":"41381361","id":"PMC_41381361","title":"Altered Excitability and Glutamatergic Synaptic Transmission in the Medium Spiny Neurons of the Nucleus Accumbens in Mice Deficient in the Heparan Sulfate Endosulfatase Sulf1.","date":"2026","source":"eNeuro","url":"https://pubmed.ncbi.nlm.nih.gov/41381361","citation_count":1,"is_preprint":false},{"pmid":"41025518","id":"PMC_41025518","title":"Production and inhibition of human Heparan 6-O-Endosulfatase SULF1.","date":"2025","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/41025518","citation_count":0,"is_preprint":false},{"pmid":"41426245","id":"PMC_41426245","title":"SULF1's Role in Endothelial Senescence and Atherosclerosis: Insights from Single-Cell and Bulk Transcriptomics.","date":"2025","source":"Journal of inflammation research","url":"https://pubmed.ncbi.nlm.nih.gov/41426245","citation_count":0,"is_preprint":false},{"pmid":"41205056","id":"PMC_41205056","title":"DCN, NPM3 and SULF1 are hub genes related to vasculogenic mimicry in lung adenocarcinoma.","date":"2025","source":"Journal of cancer research and clinical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/41205056","citation_count":0,"is_preprint":false},{"pmid":"42126087","id":"PMC_42126087","title":"Histone H3 lysine 18 lactylation-mediated SULF1 transcription promotes atherosclerosis by regulating endothelial-to-mesenchymal transition.","date":"2026","source":"Cardiovascular research","url":"https://pubmed.ncbi.nlm.nih.gov/42126087","citation_count":0,"is_preprint":false},{"pmid":"41918590","id":"PMC_41918590","title":"SULF1 and EPB41L3: Potential Biomarkers of Acute Myocardial Infarction and the Vascular Inflammatory Milieu.","date":"2026","source":"Journal of inflammation research","url":"https://pubmed.ncbi.nlm.nih.gov/41918590","citation_count":0,"is_preprint":false},{"pmid":"41986482","id":"PMC_41986482","title":"Secreted SULF1 protein modulates CD8 + T cell exhaustion by promoting TAM polarization in gastric cancer.","date":"2026","source":"Genes and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/41986482","citation_count":0,"is_preprint":false},{"pmid":"42140034","id":"PMC_42140034","title":"JOSD1 stabilizes SULF1 to activate Wnt7B-FZD1 signaling in gastric cancer.","date":"2026","source":"Translational oncology","url":"https://pubmed.ncbi.nlm.nih.gov/42140034","citation_count":0,"is_preprint":false},{"pmid":"41550717","id":"PMC_41550717","title":"MARCHF1-mediated SULF1 degradation blocks THBS2/TGF-β/SMAD2/3 signaling to reverse colon cancer metastasis and 5-FU resistance.","date":"2025","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/41550717","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":54518,"output_tokens":10203,"usd":0.1583,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":20661,"output_tokens":7463,"usd":0.14494,"stage2_stop_reason":"end_turn"},"total_usd":0.30324,"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\": 2003,\n      \"finding\": \"HSulf-1 is a cell surface-associated heparan sulfate 6-O-endosulfatase that selectively removes 6-O-sulfate groups from cell surface HSPGs, thereby diminishing receptor tyrosine kinase phosphorylation (including FGFR and EGFR family members) and downstream ERK signaling stimulated by heparin-binding growth factors FGF-2 and HB-EGF.\",\n      \"method\": \"Re-expression of HSulf-1 in ovarian cancer cell lines; measurement of HSPG sulfation, RTK phosphorylation, and ERK pathway activation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (sulfation assays, RTK phosphorylation, downstream ERK signaling, proliferation/apoptosis readouts) in a focused mechanistic study; replicated in subsequent papers\",\n      \"pmids\": [\"12686563\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"HSulf-1 re-expression attenuates HGF-mediated phosphorylation of c-Met, and downstream ERK/MAPK and AKT signaling, and reduces HGF-driven cell motility and invasion in head and neck squamous carcinoma cells.\",\n      \"method\": \"Stable transfection of HSulf-1 in SCCHN lines; RTK phosphorylation assays, transwell invasion/migration assay, thymidine incorporation\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal gain-of-function with multiple signaling and functional readouts; extends mechanism to HGF/c-Met axis\",\n      \"pmids\": [\"14973553\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"HSulf-1 and HSulf-2 suppress myeloma tumor growth in vivo, and their extracellular sulfatase activity is restricted to the local tumor cell surface; Sulfs also promote extracellular matrix deposition within tumors.\",\n      \"method\": \"Transfection of myeloma cells with HSulf-1 or HSulf-2 cDNA; SCID mouse xenograft model; histological analysis of ECM\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo xenograft with histological readouts; single lab, multiple endpoints\",\n      \"pmids\": [\"16192265\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"HSulf-1 expression inhibits angiogenesis by impairing formation of a FGF-2/FGFR1c/heparan sulfate ternary complex on vascular endothelial cells; HSulf-1 knockdown in HUVEC cells enhances FGF-2, HGF, and VEGF165 (but not heparan sulfate-independent VEGF121) proliferative signaling through ERK.\",\n      \"method\": \"Breast carcinoma xenografts with stable HSulf-1 clones; CD31 staining; Matrigel plug assay; shRNA knockdown in HUVEC; co-immunoprecipitation of FGF-2/FGFR1c/HS complex; ERK phosphorylation\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo and in vitro experiments, Co-IP of ternary complex, specific growth factor dependence on HS sulfation established by VEGF121 negative control\",\n      \"pmids\": [\"16778174\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"SULF1 increases histone H4 acetylation in HCC cells by modulating cellular HDAC and histone acetyltransferase activities, and potentiates apoptosis induced by HDAC inhibitors; SULF1 knockdown upregulates phospho-AKT and phospho-ERK.\",\n      \"method\": \"Forced SULF1 expression in Huh7 and Hep3B; HDAC/HAT activity assays; shRNA knockdown; nude mouse xenografts; Western blot for p-AKT, p-ERK\",\n      \"journal\": \"Gastroenterology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple functional assays in vitro and in vivo; single lab\",\n      \"pmids\": [\"16762634\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"SULF1 and SULF2 are the major regulators of heparan sulfate 6-O-desulfation in vivo; they reduce GDNF binding to heparan sulfate and thereby enhance GDNF signaling and neurite sprouting required for esophageal innervation. Sulf1/Sulf2 double-knockout mice exhibit esophageal contractile malfunction due to loss of GDNF-dependent neural innervation.\",\n      \"method\": \"Sulf1/Sulf2 genetic mouse knockouts; biochemical HS desulfation assays; GDNF binding assay; neurite sprouting assay; esophageal function tests\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — genetic loss-of-function in mice with biochemical (GDNF-HS binding), cell signaling, and organ-level functional readouts; neurite sprouting specificity established by GDNF vs. neurotrophin controls\",\n      \"pmids\": [\"17720696\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"HSulf-1 expression is epigenetically silenced in ovarian cancer through CpG methylation of exon 1A and increased histone H3 methylation at the HSulf-1 locus; treatment with 5-aza-2'-deoxycytidine restores HSulf-1 transcription.\",\n      \"method\": \"Bisulfite sequencing of CpG sites; chromatin immunoprecipitation (H3 methylation); 5-aza-dC treatment; siRNA knockdown functional assays\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP + bisulfite sequencing + pharmacological demethylation; single lab\",\n      \"pmids\": [\"17310998\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"HSulf-1 inhibits autocrine EGFR-ERK pathway activation driven by the heparin-binding EGF family members amphiregulin and HB-EGF in breast cancer cells; this is associated with reduced cyclin D1 levels and altered cell cycle distribution.\",\n      \"method\": \"shRNA knockdown of HSulf-1 in stable clonal lines; neutralizing antibodies against amphiregulin and HB-EGF; ERK phosphorylation; cyclin D1 Western blot; cell cycle analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (shRNA, neutralizing antibodies, signaling readouts); single lab\",\n      \"pmids\": [\"17363371\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Asparagine-linked (N-linked) glycosylation of Sulf1 is essential for its enzymatic activity, membrane targeting, secretion, and heparin/HS binding; N-glycanase cleavage of N-linked glycans abolishes 6-O-desulfation activity.\",\n      \"method\": \"Domain mapping with deletion mutants; glycosylation inhibitor studies; N-glycanase cleavage; heparin binding and enzymatic activity assays on quail Sulf1 (ortholog)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct biochemical enzymatic assays combined with pharmacological and enzymatic N-glycan removal; multiple orthogonal methods in single study\",\n      \"pmids\": [\"17855356\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The unique hydrophilic domain (HD, ~320 aa) of Sulf1 is required for enzymatic activity and acts as a high-affinity heparin/heparan sulfate interaction domain; surface plasmon resonance indicates nanomolar affinity; HD binding to HS depends on presence of 6-O-sulfate substrate groups, suggesting substrate turnover facilitates enzyme release; deletion of the inner HD region increases Sulf1 secretion without affecting activity.\",\n      \"method\": \"HD deletion mutants; GST-HD fusion proteins; surface plasmon resonance; heparinase sensitivity; cell surface binding assays; FGF-2 signaling assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution with multiple deletion constructs, SPR kinetic measurements, functional signaling validation; rigorous domain-function mapping\",\n      \"pmids\": [\"19666466\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"HSulf-1 and HSulf-2 selectively remove 6-O-sulfate groups from N,6-O,2-O-trisulfated disaccharides of intact heparan sulfate on the cell surface and extracellular matrix, as detected by flow cytometry with anti-HS antibody RB4CD12; both Sulf activities are potently inhibited by PI-88, a sulfated heparin mimetic.\",\n      \"method\": \"Flow cytometry with anti-HS antibody; disaccharide compositional analysis; ELISA with recombinant HSulfs; conditioned medium activity on microvessels; PI-88 inhibition assay\",\n      \"journal\": \"Glycobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct enzymatic assays on cell surface and purified substrates; multiple orthogonal detection methods; inhibitor characterization\",\n      \"pmids\": [\"19822709\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"vHNF1 (variant hepatic nuclear factor 1, encoded by TCF2/HNF1β) directly represses HSulf-1 transcription by binding to two vHNF1-responsive elements in the HSulf-1 promoter; shRNA knockdown of vHNF1 increases HSulf-1 expression and sensitizes cells to cisplatin/paclitaxel.\",\n      \"method\": \"Chromatin immunoprecipitation; reporter assay; shRNA knockdown of vHNF1; Western blot; xenograft experiments\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and reporter assay with functional rescue; single lab\",\n      \"pmids\": [\"19487294\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Promoter hypermethylation of the HSulf-1 5' regulatory region (approximately 400 bp with high basal promoter activity) correlates with HSulf-1 silencing in breast and gastric cancer cell lines and primary tumors.\",\n      \"method\": \"Luciferase reporter to characterize promoter; bisulfite sequencing; correlation with mRNA expression; cell-free DNA methylation in patient serum\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — promoter characterization with reporter assay plus bisulfite sequencing; single lab\",\n      \"pmids\": [\"19006069\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Haploinsufficiency of SULF1 (due to interstitial deletion at 8q13) is strongly implicated in mesomelia-synostoses syndrome, a skeletal dysplasia with mesomelic limb shortening and acral synostoses; SULF1 shows highest transcript levels in human osteoblasts and cartilage.\",\n      \"method\": \"Whole-genome array CGH in MSS patients; breakpoint sequencing; quantitative RT-PCR of SULF1 in human tissues\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genomic deletion mapping with quantitative expression analysis; genetic evidence from multiple unrelated families\",\n      \"pmids\": [\"20602915\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"HSulf-1 transcription is downregulated by hypoxia through HIF-1α and HIF-2α recruitment to two functional hypoxia-responsive elements (HREs) on the HSulf-1 promoter; HSulf-1 depletion under hypoxia enhances FGF2 signaling through FGFR2 and promotes cell migration and invasion.\",\n      \"method\": \"Chromatin immunoprecipitation with HIF-1α and HIF-2α antibodies; HIF-1α shRNA rescue experiments; shRNA depletion of HSulf-1 and FGFR2; migration/invasion assays under hypoxia\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP identifies HIF binding to native promoter, genetic rescue with HIF-1α knockdown, orthogonal FGFR2 depletion confirms pathway; multiple methods\",\n      \"pmids\": [\"21266348\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"hSulf-1 re-expression downregulates VEGFR-2 phosphorylation and inhibits angiogenesis in ovarian and hepatocellular cancer cells and xenografts; hSulf-1 knockdown enhances VEGFR-2 phosphorylation.\",\n      \"method\": \"hSulf-1 expression vectors and shRNA; Western blot for p-VEGFR-2; nude mouse xenografts; tumor microvessel density (CD31 staining)\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — paired gain- and loss-of-function in vitro and in vivo; single lab\",\n      \"pmids\": [\"21853101\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Sulf1 and Sulf2 have distinct organ-specific effects on heparan sulfate sulfation in vivo: Sulf1 knockout mice show predominant increases in ΔUA2S-GlcNS6S (trisulfated) disaccharides, with Sulf1 having greater overall impact on HS desulfation than Sulf2 despite lower mRNA levels; Sulfs do not alter chondroitin sulfate composition.\",\n      \"method\": \"Disaccharide analysis of HS from multiple organs of Sulf1 and Sulf2 knockout mice; correlation of mRNA expression with HS changes\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vivo biochemical disaccharide analysis across 8 organs in genetic knockouts; demonstrates substrate specificity for HS over chondroitin sulfate\",\n      \"pmids\": [\"22298771\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"SULF1 inhibits heparan sulfate-dependent Wnt/β-catenin signaling at the cell surface in gastric cancer cells that depend on extracellular Wnt signaling (MKN28), but has no effect in cells with constitutively active intracellular Wnt/β-catenin (AGS); Wnt3a rescue and β-catenin shRNA confirm pathway dependence; HSulf-1 alters HS structure on cell surface.\",\n      \"method\": \"HSulf-1 stable transfection; TCF/LEF reporter assay; Western blot for β-catenin target genes; Wnt3a cDNA rescue; β-catenin shRNA; HSPG epitope analysis\",\n      \"journal\": \"Cancer science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal approaches including reporter, rescue, and shRNA; pathway specificity tested with two cell lines; single lab\",\n      \"pmids\": [\"21722266\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"The hydrophilic domain (HD) of Sulf1 mediates specific HS binding through at least two separate binding sites (inner and C-terminal regions of HD); substrate turnover autoregulates Sulf1/HS association (Sulf1 binds 6-O-desulfated HS significantly weaker); dynamic single-molecule force spectroscopy reveals HD off-rate ~500-fold higher than SPR-determined value, consistent with processive action along HS chains.\",\n      \"method\": \"Affinity chromatography; AFM single-molecule force spectroscopy; immunofluorescence on living cells; HD subdomain deletion constructs\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — single-molecule biophysics combined with biochemical domain mapping; novel autoregulation mechanism directly demonstrated\",\n      \"pmids\": [\"23891937\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Drosophila Sulf1 (ortholog) reduces extracellular Wnt/Wingless protein levels by facilitating Wg degradation; it inhibits Wg binding to the HSPG Dally; human Sulf1 expressed in Drosophila wing disc similarly lowers extracellular Wg levels, demonstrating conserved intrinsic activity.\",\n      \"method\": \"In vitro, in vivo, and ex vivo Wg stability assays in Drosophila; HS-Wg binding assay; human SULF1 expression in Drosophila disc\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple systems (in vitro, in vivo, ex vivo); mechanistic insight into Wg degradation; Drosophila ortholog with human SULF1 cross-species validation\",\n      \"pmids\": [\"23300081\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Sulf1 knockdown in zebrafish results in decreased BMP signaling, reduced Pax7-expressing dermomyotome cells, loss of sdf1/cxcl12 expression, and impaired somite morphogenesis/myoseptum formation; pharmacological BMP inhibition rescues Pax7 expression, myoseptum, and pigmentation; FGF pathway activation rescues neuromast spacing.\",\n      \"method\": \"Antisense morpholino knockdown in zebrafish; pharmacological BMP and FGF pathway inhibitors/activators; in situ hybridization; immunofluorescence\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockdown with pharmacological epistasis testing; two independent pathways tested; zebrafish ortholog\",\n      \"pmids\": [\"23583585\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Sulf1 restricts Shh ligand diffusion and shapes the Shh morphogen gradient in the ventral neural tube of Xenopus; Sulf1 knockdown results in a less steep Shh gradient and altered ventral neural progenitor specification.\",\n      \"method\": \"Single-cell injection of GFP-tagged Shh mRNA in Xenopus embryos; Sulf1 morpholino knockdown; endogenous Shh distribution analysis; neural progenitor marker analysis\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live imaging of morphogen gradients combined with loss-of-function; single lab, Xenopus ortholog\",\n      \"pmids\": [\"24768893\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Sulf1 in zebrafish regulates VegfA165-mediated arterial specification; sulf1 morphants lack arterial identity (reduced notch, ephrinB2) with increased venous marker flt4 in dorsal aorta; co-injection of vegfa165 mRNA rescues circulatory defects; in vitro, lack of SULF1 downregulates VEGFA-mediated arterial marker expression.\",\n      \"method\": \"Antisense morpholino knockdown in zebrafish; mRNA rescue injection; in situ hybridization for arterial/venous markers; in vitro VEGFA signaling assays\",\n      \"journal\": \"Angiogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — morpholino knockdown with mRNA rescue and pathway marker analysis in vivo plus in vitro validation; zebrafish ortholog\",\n      \"pmids\": [\"23959107\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Loss of HSulf-1 in ovarian cancer promotes tumorigenicity by decreasing proapoptotic Bim protein expression; decreased Bim is mediated by increased p-ERK signaling (rescued by ERK inhibitor PD98059); PI3K/AKT inhibition has no effect on Bim levels; rescue of Bim in HSulf-1 knockdown cells retards tumor growth in vivo.\",\n      \"method\": \"shRNA stable knockdown; Western blot for Bim; ERK inhibitor (PD98059) and PI3K inhibitor (LY294002) treatment; rescue Bim expression; soft agar colony assay; nude mouse xenografts\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological and genetic epistasis linking HSulf-1 loss → ERK → Bim; specific pathway exclusion (AKT negative); single lab\",\n      \"pmids\": [\"24596063\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The hydrophilic domain (HD) of Sulf1 exhibits catch bond behavior with its glycosaminoglycan (HS) substrate: bond lifetime increases under force for 6-O-sulfated HS but shows only slip bond interaction when 6-O-sulfation is absent; two coupled slip-bond states underlie the catch bond, with energy difference ΔE ≈ 9 kBT and compliance length Δx ≈ 3.2 nm.\",\n      \"method\": \"AFM-based force clamp spectroscopy and dynamic force spectroscopy; two-state two-path theoretical model fitting; comparison of 6-O-sulfated vs. desulfated GAG substrates\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — quantitative single-molecule biophysics with two orthogonal AFM modes; mechanistic model with defined energy landscape; substrate specificity confirmed by desulfated GAG control\",\n      \"pmids\": [\"25863062\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Sulf1 has ligand-specific effects on Wnt signaling in Xenopus: Sulf1 overexpression inhibits canonical Wnt8a signaling while enhancing non-canonical Wnt11b signaling; Sulf1 differentially affects membrane accumulation and extracellular levels of Wnt8a and Wnt11b tagged ligands.\",\n      \"method\": \"Xenopus assays; fluorescently tagged Wnt ligands in ectodermal explants; canonical and non-canonical Wnt pathway reporters; mRNA overexpression\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — well-established Xenopus assays with multiple Wnt ligands; ligand-specific effects established by direct comparison; single lab\",\n      \"pmids\": [\"25681501\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Sulf1 deficiency in cerebellar granule cells leads to reduced neurite length, reduced cell survival, and reduced migration capacity; impairments correlate with Sulf-specific alterations in FGF2, GDNF, and NGF signaling, but not Shh signaling; biochemical analysis reveals Sulf1-specific changes in 6-O-, 2-O- and N-sulfation of cerebellar HS in vivo.\",\n      \"method\": \"Primary cerebellar granule cells from Sulf1 KO mice; neurite length measurement; cell survival assays; migration assays; signaling pathway analysis; HS biochemical disaccharide analysis; HS epitope immunostaining\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with multiple cellular and biochemical readouts; signaling pathway specificity established; single lab\",\n      \"pmids\": [\"26448642\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"HSulf-1 loss promotes aerobic glycolysis (Warburg effect) in ovarian cancer by upregulating glycolytic genes (Glut1, HKII, LDHA) and metabolites; this occurs mechanistically through HB-EGF-mediated p-ERK activation driving c-Myc induction; increased inhibitory PDH phosphorylation blocks glucose flux into TCA cycle; HSulf-1 overexpression reverses the glycolytic phenotype.\",\n      \"method\": \"shRNA knockdown and overexpression; isotope tracer metabolomics (glucose flux into TCA); metabolomic profiling; Western blot for glycolytic enzymes; pharmacological inhibition of c-Myc; oxygen consumption rate measurement\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — isotope tracer metabolomics plus pharmacological c-Myc inhibition establishing mechanistic pathway; multiple orthogonal methods; single lab\",\n      \"pmids\": [\"26378042\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"TNF-α induces Sulf-1 expression in fibroblasts via NF-κB, ERK1/2, and p38 MAPK pathways; TNF-α-induced Sulf-1 is secreted as an active enzyme that causes 6-O-desulfation of HS and reduces ERK1/2 activation and proliferation in response to FGF-1; Sulf-1 siRNA rescues FGF-1-induced responses in TNF-α-treated cells.\",\n      \"method\": \"TNF-α treatment of MRC-5 fibroblasts; pathway inhibitors for NF-κB/ERK1/2/p38; HS disaccharide compositional analysis; siRNA knockdown of Sulf-1; ERK phosphorylation and proliferation assays\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA rescue confirms causal role; HS compositional analysis; pathway inhibitors identify upstream regulators; single lab\",\n      \"pmids\": [\"27693418\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Sulf1 and Sulf2 are required for corticospinal tract (CST) axon guidance: in DKO mice, increased 6-O-sulfated HS causes abnormal accumulation of Slit2 protein on brain surfaces, which repels CST axons dorsally; in utero electroporation of Sulf1/2 into radial glia rescues the CST defect; proteomic analysis identified Slit2 as the key molecule.\",\n      \"method\": \"Sulf1/Sulf2 double-KO mice; in utero electroporation rescue; immunofluorescence for Slit2; proteomics; CST tract tracing\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO, in utero rescue, proteomics, and functional imaging; Slit2 identified by unbiased proteomics and functionally validated as key molecular mediator\",\n      \"pmids\": [\"29062064\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SULF1 loss was identified as contributing to cisplatin resistance in ovarian cancer cells by genome-scale CRISPR/Cas9 knockout screening; CCK-8 and RT-PCR validation confirmed SULF1 involvement in cisplatin sensitivity.\",\n      \"method\": \"Genome-scale CRISPR/Cas9 knockout (GeCKO) library screen; CCK-8 viability assay; RT-PCR validation\",\n      \"journal\": \"American journal of cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — unbiased genome-wide screen with direct validation; replicates prior mechanistic observations on cisplatin resistance\",\n      \"pmids\": [\"31218106\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SULF1 produced by bone marrow fibroblasts suppresses Wnt3A-driven growth of prostate cancer cells in a 3D biomimetic triculture model incorporating perlecan (HSPG2); M2-like macrophages increase SULF1 and HSPG2 levels produced by fibroblasts.\",\n      \"method\": \"SULF1 CRISPR/Cas9 knockout fibroblasts; 3D hydrogel triculture model with perlecan, PCa cells, macrophages, and fibroblasts; PCa tumoroid growth assay; primary tissue validation\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO in physiologically relevant 3D model; tissue validation; single lab\",\n      \"pmids\": [\"32413029\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"SULF1 catalyzes the release of TGF-β1 from TGFBR3 (betaglycan) on the surface of gastric cancer cells; cancer-associated fibroblast-secreted SULF1 binds TGFBR3 and thereby activates TGF-β1/SMAD signaling, promoting metastasis and cisplatin resistance; TGF-β1 in turn induces SULF1 expression through the TGF-β1/SMAD pathway, forming a positive feedback loop.\",\n      \"method\": \"Co-immunoprecipitation of SULF1 with TGFBR3; CRISPR/Cas9 and siRNA knockdown; Western blot for SMAD signaling; migration/invasion assays; xenograft models; TGFβ pathway inhibitors\",\n      \"journal\": \"Cell death discovery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifies SULF1-TGFBR3 interaction; multiple functional and signaling readouts; single lab\",\n      \"pmids\": [\"38438372\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"SULF1 promotes pulmonary fibrosis through the TGF-β1/SMAD pathway; TGF-β1 induces SULF1 expression in fibroblasts; SULF1 knockdown suppresses fibroblast activation, proliferation, migration, and invasion under TGF-β1-driven and non-TGF-β1 conditions; SULF1 catalyzes release of TGF-β1 bound to TGFβRIII (TGFBR3), activating SMAD signaling.\",\n      \"method\": \"Co-immunoprecipitation; lentiviral shRNA knockdown; Western blot; ELISA; functional fibroblast assays; transcriptome sequencing of IPF patient samples\",\n      \"journal\": \"Journal of translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifies SULF1-TGFBR3 interaction; lentiviral KD with multiple functional readouts; transcriptomic patient data; single lab\",\n      \"pmids\": [\"39354547\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SULF1 enzymatic activity requires co-expression of sulfatase-modifying factor 1 (SUMF1) which converts the active-site cysteine to Cα-formylglycine (FGly); SULF1 activity also requires a Ca²⁺ ion; a marine fucosylated chondroitin sulfate inhibits SULF1 with IC50 ~0.05–0.07 μg/mL through mixed-mode inhibition.\",\n      \"method\": \"Recombinant SULF1 expression in HEK293F/T; co-expression with SUMF1; Ni²⁺-affinity purification; enzymatic activity assays; kinetic inhibition analysis; active site cysteine-to-FGly conversion verification\",\n      \"journal\": \"Glycobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct biochemical reconstitution of enzymatic activation mechanism; active site modification confirmed; kinetics of inhibition characterized; rigorous in vitro enzymatic study\",\n      \"pmids\": [\"41025518\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"CAF-derived SULF1 is required for cancer cell invasion in HNSCC: CRISPR/Cas9-knockout of SULF1 in primary CAFs reduces fibroblast proliferation and markedly impairs Cal33 cancer cell migration and invasion in vitro and in 3D spheroid cocultures; SULF2 from tumor cells does not compensate for SULF1 loss.\",\n      \"method\": \"CRISPR/Cas9 SULF1 knockout in primary CAFs; transwell migration/invasion assays; two-photon microscopy in 3D spheroid cocultures; proteomics confirming SULF1 absence and no SULF2 compensation\",\n      \"journal\": \"Cancer medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR KO with 3D coculture model and proteomics; non-redundancy with SULF2 established; single lab\",\n      \"pmids\": [\"41549062\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"JOSD1 deubiquitinase stabilizes SULF1 protein; stabilized SULF1 directly binds Frizzled-1 (FZD1) and facilitates Wnt7B-FZD1 complex formation, activating canonical Wnt/β-catenin signaling and inducing β-catenin nuclear accumulation in gastric cancer; JOSD1 oncogenic effects are strictly dependent on SULF1 stabilization.\",\n      \"method\": \"Co-immunoprecipitation; ubiquitination assays; rescue experiments; Western blot; β-catenin nuclear translocation assay; xenograft models\",\n      \"journal\": \"Translational oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifies SULF1-FZD1 interaction and JOSD1-SULF1 interaction; ubiquitination assays; rescue experiments; single lab\",\n      \"pmids\": [\"42140034\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Sulf1 knockout in the nucleus accumbens D1- or D2-receptor-expressing medium spiny neurons causes cell-type-specific electrophysiological defects: D2-MSNs show reduced rheobase with blunted firing at larger currents; D1-MSNs show more depolarized resting potential and increased AMPA/NMDA ratio; Sulf1 KO impairs reward learning (via D1 pathway) and aversion learning (via D2 pathway) in mice.\",\n      \"method\": \"Conditional Sulf1 KO using Drd1-Cre and Drd2-Cre; whole-cell patch-clamp recording; behavioral tests (CPP, inhibitory avoidance); CRISPR-Cas9 floxed mouse generation\",\n      \"journal\": \"Journal of neurochemistry / eNeuro\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-type-specific conditional KO with electrophysiology and behavioral validation; two papers from same group with convergent findings\",\n      \"pmids\": [\"41486756\", \"41381361\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SULF1 is a cell-surface and secreted 6-O-endosulfatase whose unique hydrophilic domain (HD) binds heparan sulfate chains with nanomolar affinity via a catch-bond mechanism dependent on 6-O-sulfate groups, and whose active-site cysteine must be converted to Cα-formylglycine by SUMF1 for enzymatic activity; by selectively removing 6-O-sulfate from N,6-O,2-O-trisulfated heparan sulfate on HSPGs, SULF1 modulates the availability and receptor presentation of heparin-binding growth factors (FGF-2, HGF, HB-EGF, VEGF165, GDNF) and morphogens (Wnt, Shh, Slit2, BMP, PDGF), with context-dependent consequences that include attenuation of receptor tyrosine kinase (FGFR, EGFR, c-Met, VEGFR-2) and downstream ERK/AKT/STAT3/Wnt/β-catenin signaling, shaping of morphogen gradients (Shh, Wnt, Slit2), axon guidance, and organ development; SULF1 gene expression is regulated by epigenetic silencing (CpG methylation, histone H3 methylation), transcriptional repression by vHNF1, hypoxia-driven HIF-α binding to promoter HREs, TNF-α/NF-κB induction, and post-translational stabilization by the deubiquitinase JOSD1, while a naturally occurring short splice isoform (SULF1B) and catalytically inactive short splice variants can antagonize or bypass full-length SULF1 function.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"SULF1 is a cell-surface and secreted heparan sulfate 6-O-endosulfatase that remodels the sulfation landscape of heparan sulfate proteoglycans (HSPGs) to control the bioavailability and receptor presentation of heparin-binding growth factors and morphogens [#0, #10]. It selectively hydrolyzes 6-O-sulfate groups from the N,6-O,2-O-trisulfated disaccharides of intact cell-surface and matrix heparan sulfate, and is the dominant in vivo regulator of HS 6-O-desulfation, with substrate specificity for HS over chondroitin sulfate [#10, #16]. Enzymatic competence depends on a unique ~320-residue hydrophilic domain (HD) that confers nanomolar, 6-O-sulfate-dependent heparan sulfate binding through a catch-bond whose lifetime increases under force only on sulfated substrate, allowing processive action and substrate-turnover-driven release along HS chains [#9, #18, #24]; activity additionally requires N-linked glycosylation, a Ca2+ ion, and SUMF1-mediated conversion of the active-site cysteine to Cα-formylglycine [#8, #34]. By stripping 6-O-sulfate from HSPGs, SULF1 attenuates ternary growth-factor/receptor/HS complex formation and downstream signaling for FGF-2/FGFR, HB-EGF and amphiregulin/EGFR, HGF/c-Met, and VEGF165/VEGFR-2, while conversely enhancing GDNF signaling by releasing GDNF from HS [#0, #1, #3, #7, #15, #5]. In development it shapes morphogen gradients and tissue patterning—restricting Shh diffusion in the neural tube, exerting ligand-specific control over canonical versus non-canonical Wnt signaling, regulating BMP-dependent somitogenesis and VEGFA-driven arterial specification, and guiding corticospinal axons by limiting Slit2 accumulation [#21, #25, #20, #22, #29]. SULF1 acts as a context-dependent tumor suppressor whose loss enhances ERK/AKT-driven proliferation, anti-apoptotic and metabolic reprogramming (HB-EGF→ERK→c-Myc-driven glycolysis, ERK→Bim suppression) and cisplatin resistance, and its expression is controlled by CpG and histone methylation, vHNF1 repression, hypoxia-driven HIF binding, TNF-α/NF-κB induction, and JOSD1-mediated protein stabilization [#0, #23, #27, #6, #11, #14, #36]. Haploinsufficiency of SULF1 is implicated in mesomelia-synostoses syndrome, a skeletal dysplasia [#13].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"Established the founding biochemical activity—that SULF1 is a cell-surface HS 6-O-endosulfatase whose desulfation activity directly dampens growth-factor-driven RTK signaling—answering what this enzyme does to HSPGs and downstream pathways.\",\n      \"evidence\": \"Re-expression of HSulf-1 in ovarian cancer lines with sulfation, RTK phosphorylation, and ERK readouts\",\n      \"pmids\": [\"12686563\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve the precise disaccharide substrate\", \"Catch-bond/processivity mechanism unknown at this stage\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Extended the desulfation-attenuates-signaling logic to the HGF/c-Met axis, showing SULF1 suppresses tumor cell motility and invasion, broadening the set of regulated growth-factor pathways.\",\n      \"evidence\": \"Stable HSulf-1 transfection in SCCHN cells with RTK phosphorylation, invasion, and proliferation assays\",\n      \"pmids\": [\"14973553\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance not tested here\", \"Direct effect on HGF-HS binding not measured\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Demonstrated SULF1 acts as a tumor suppressor in vivo and that its sulfatase activity is spatially restricted to the local cell surface, addressing where the enzyme operates.\",\n      \"evidence\": \"Myeloma cDNA transfection with SCID xenografts and ECM histology\",\n      \"pmids\": [\"16192265\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Mechanism of ECM deposition not defined\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Showed SULF1 controls angiogenesis by blocking assembly of the FGF-2/FGFR1c/HS ternary complex, with HS-independent VEGF121 as a negative control establishing sulfation-dependence.\",\n      \"evidence\": \"Breast xenografts, Matrigel plug, HUVEC knockdown, and Co-IP of the ternary complex\",\n      \"pmids\": [\"16778174\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve which HSPG core proteins are key in endothelium\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Defined the in vivo developmental role and substrate-bidirectionality—SULF1/2 are the major HS 6-O-desulfators and can enhance (rather than only attenuate) signaling by releasing GDNF from HS to drive esophageal innervation.\",\n      \"evidence\": \"Sulf1/Sulf2 double-knockout mice with HS desulfation assays, GDNF binding, neurite sprouting, and organ function tests\",\n      \"pmids\": [\"17720696\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Individual contributions of Sulf1 vs Sulf2 not separated\", \"Mechanism of GDNF release vs FGF attenuation contrast not fully reconciled\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Identified epigenetic silencing (CpG and histone H3 methylation) as a mechanism of SULF1 loss in cancer, explaining how its tumor-suppressor function is inactivated.\",\n      \"evidence\": \"Bisulfite sequencing, ChIP for H3 methylation, and 5-aza-dC restoration in ovarian cancer\",\n      \"pmids\": [\"17310998\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Upstream trigger of methylation unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Linked SULF1 to autocrine EGFR signaling and cell-cycle control via amphiregulin/HB-EGF and cyclin D1, and established that N-linked glycosylation is essential for enzymatic activity, secretion, and HS binding.\",\n      \"evidence\": \"shRNA, neutralizing antibodies, ERK/cyclin D1 readouts; glycosylation/N-glycanase studies on quail Sulf1 ortholog\",\n      \"pmids\": [\"17363371\", \"17855356\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Glycosylation site mapping incomplete\", \"EGFR-ligand studies in single lab\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Mapped the unique hydrophilic domain as the high-affinity, 6-O-sulfate-dependent HS-interaction module required for activity, and showed substrate turnover facilitates enzyme release—an early model for processivity.\",\n      \"evidence\": \"HD deletion mutants, GST-HD fusions, SPR, and FGF-2 signaling assays\",\n      \"pmids\": [\"19666466\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Single-molecule kinetics not yet measured\", \"Structure of HD-HS interface unresolved\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Defined the precise substrate (N,6-O,2-O-trisulfated disaccharides) and a pharmacological inhibitor (PI-88), and identified vHNF1 repression and promoter hypermethylation as transcriptional/epigenetic regulators of SULF1.\",\n      \"evidence\": \"Flow cytometry with RB4CD12 antibody, disaccharide analysis, PI-88 inhibition; ChIP/reporter for vHNF1; bisulfite sequencing in breast/gastric cancer\",\n      \"pmids\": [\"19822709\", \"19487294\", \"19006069\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Catalytic mechanism on intact chains not structurally resolved\", \"Regulator hierarchy across tissues unknown\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Connected SULF1 to human Mendelian disease, implicating haploinsufficiency in mesomelia-synostoses syndrome and identifying skeletal/cartilage tissues as high-expression sites.\",\n      \"evidence\": \"Array CGH and breakpoint sequencing in MSS patients with qRT-PCR tissue profiling\",\n      \"pmids\": [\"20602915\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Causation by deletion alone not proven (contiguous genes possible)\", \"Skeletal HS-substrate mechanism not defined\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Showed hypoxia represses SULF1 via HIF-1α/HIF-2α binding to promoter HREs, releasing FGF2/FGFR2 signaling and invasion, and that SULF1 downregulates VEGFR-2 phosphorylation to inhibit angiogenesis—integrating SULF1 into the tumor microenvironment.\",\n      \"evidence\": \"ChIP with HIF antibodies, HIF-1α shRNA rescue, FGFR2 depletion; gain/loss-of-function with p-VEGFR-2 and microvessel density\",\n      \"pmids\": [\"21266348\", \"21853101\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"VEGFR-2 study single lab\", \"Crosstalk between hypoxia repression and other regulators not integrated\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Quantified Sulf1's distinct, organ-specific in vivo impact on HS sulfation (greater than Sulf2 despite lower mRNA) with specificity for HS over chondroitin sulfate, and showed SULF1 selectively blocks cell-surface HS-dependent Wnt/β-catenin signaling.\",\n      \"evidence\": \"Disaccharide analysis across 8 organs in Sulf1/Sulf2 KO mice; TCF/LEF reporter, Wnt3a rescue, and β-catenin shRNA in gastric cancer lines\",\n      \"pmids\": [\"22298771\", \"21722266\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Wnt study limited to two cell lines, single lab\", \"Basis for Sulf1>Sulf2 potency not explained\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Resolved the biophysical basis of HD-HS engagement—two binding sites and a single-molecule off-rate ~500-fold higher than SPR, supporting processive action—and showed conserved Wnt/Wingless control across orthologs plus BMP/FGF roles in somitogenesis.\",\n      \"evidence\": \"AFM force spectroscopy and HD subdomain mapping; Drosophila Wg stability assays with human SULF1 cross-rescue; zebrafish morpholino with BMP/FGF epistasis\",\n      \"pmids\": [\"23891937\", \"23300081\", \"23583585\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Wg-degradation mechanism not molecularly resolved\", \"Zebrafish/Drosophila ortholog findings need vertebrate confirmation\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Established SULF1 as a morphogen-gradient shaper (restricting Shh diffusion, regulating VEGFA165 arterial specification) and detailed a tumor-suppressor mechanism in which SULF1 loss elevates p-ERK to suppress proapoptotic Bim.\",\n      \"evidence\": \"GFP-Shh imaging in Xenopus, sulf1 morphant rescue in zebrafish; ERK/PI3K inhibitor epistasis and Bim rescue with xenografts\",\n      \"pmids\": [\"24768893\", \"23959107\", \"24596063\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Morphogen studies in non-mammalian models\", \"Bim/ERK link from single lab\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined the molecular catch-bond mechanism (force-prolonged lifetime on 6-O-sulfated HS, slip-bond when desulfated; ΔE≈9 kBT, Δx≈3.2 nm) and broadened SULF1 functions to metabolic reprogramming, neuronal HS biology, and ligand-specific Wnt control.\",\n      \"evidence\": \"AFM force-clamp/dynamic spectroscopy with two-state model; isotope-tracer metabolomics in ovarian cancer; Sulf1-KO cerebellar granule cell assays; tagged-Wnt Xenopus explants\",\n      \"pmids\": [\"25863062\", \"26378042\", \"26448642\", \"25681501\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of catch bond not crystallographically defined\", \"Tissue-specific signaling outcomes from single labs\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identified TNF-α/NF-κB/MAPK as an inflammatory inducer of secreted, catalytically active SULF1 that dampens FGF-1 signaling, integrating SULF1 into inflammatory regulation.\",\n      \"evidence\": \"TNF-α treatment of MRC-5 fibroblasts with pathway inhibitors, HS disaccharide analysis, and siRNA rescue\",\n      \"pmids\": [\"27693418\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single cell type\", \"In vivo inflammatory relevance not tested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrated SULF1/2 are required for corticospinal axon guidance by limiting Slit2 accumulation, with unbiased proteomics identifying Slit2 as the mediator and in utero rescue confirming causation.\",\n      \"evidence\": \"Sulf1/Sulf2 DKO mice, in utero electroporation rescue, proteomics, and CST tract tracing\",\n      \"pmids\": [\"29062064\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Sulf1 vs Sulf2 individual contributions not separated\", \"Direct Slit2-HS biochemistry not shown\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Confirmed via unbiased genome-scale screening that SULF1 loss contributes to cisplatin resistance, corroborating earlier mechanistic links.\",\n      \"evidence\": \"GeCKO CRISPR knockout screen in ovarian cancer with CCK-8 and RT-PCR validation\",\n      \"pmids\": [\"31218106\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Resistance mechanism downstream of SULF1 loss not dissected here\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed stromal (fibroblast-derived) SULF1 acts non-cell-autonomously to suppress Wnt3A-driven prostate cancer growth in a perlecan-containing 3D model, with macrophage regulation of SULF1/HSPG2 levels.\",\n      \"evidence\": \"CRISPR-KO fibroblasts in a 3D hydrogel triculture with tumoroid growth and tissue validation\",\n      \"pmids\": [\"32413029\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Molecular basis of macrophage induction not defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified a TGFBR3 (betaglycan)-dependent activity in which SULF1 releases bound TGF-β1 to activate SMAD signaling, creating a TGF-β1/SMAD positive-feedback loop driving cancer metastasis, cisplatin resistance, and pulmonary fibrosis.\",\n      \"evidence\": \"Co-IP of SULF1-TGFBR3, CRISPR/shRNA knockdown, SMAD readouts, xenografts (gastric cancer); Co-IP, shRNA, and IPF transcriptomics (lung fibrosis)\",\n      \"pmids\": [\"38438372\", \"39354547\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether TGF-β1 release is sulfatase-dependent or binding-dependent not fully resolved\", \"Co-IP without structural mapping of SULF1-TGFBR3 interface\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Reconstituted the SULF1 activation mechanism in vitro—SUMF1-mediated cysteine-to-formylglycine conversion plus a required Ca2+ ion—and characterized a fucosylated chondroitin sulfate as a mixed-mode inhibitor.\",\n      \"evidence\": \"Recombinant SULF1/SUMF1 co-expression, Ni-affinity purification, FGly conversion verification, and inhibition kinetics\",\n      \"pmids\": [\"41025518\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal/cryo-EM structure of activated enzyme\", \"Inhibitor selectivity over SULF2 not established\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Established SULF1 as a regulated protein target—JOSD1 deubiquitinase stabilizes SULF1, which then binds FZD1 to promote Wnt7B/FZD1 complex and β-catenin signaling—and confirmed non-redundant stromal SULF1 requirement for HNSCC invasion.\",\n      \"evidence\": \"Co-IP, ubiquitination and rescue assays, β-catenin translocation, xenografts (gastric cancer); CRISPR-KO in primary CAFs with 3D coculture and proteomics (HNSCC)\",\n      \"pmids\": [\"42140034\", \"41549062\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"FZD1-promoting Wnt activity contrasts with prior Wnt-inhibitory findings; context dependence unresolved\", \"Single labs\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Revealed a cell-type-specific neuronal role: Sulf1 shapes intrinsic and synaptic properties of D1- and D2-MSNs in the nucleus accumbens and is required for reward and aversion learning.\",\n      \"evidence\": \"Conditional Sulf1 KO with Drd1-/Drd2-Cre, whole-cell patch-clamp, and behavioral assays\",\n      \"pmids\": [\"41486756\", \"41381361\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"HS-substrate or growth-factor pathway underlying MSN phenotype not identified\", \"Same group, convergent but not independently replicated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SULF1's bidirectional context-dependent effects on Wnt signaling (inhibitory cell-surface block versus FZD1-promoting complex formation) are reconciled, and the atomic structure of the activated HD-HS catch-bond interface, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No high-resolution structure of SULF1 or the HD-HS complex\", \"Determinants of attenuating vs enhancing signaling outcomes not defined\", \"Mechanistic basis for Sulf1/Sulf2 non-redundancy unresolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 10, 16, 34]},\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [0, 10, 16]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [9, 18, 24]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 3, 5, 32]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 10]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [2, 28]},\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [2, 10]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 3, 17, 32]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [5, 20, 21, 22, 29]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [13, 23, 27, 30, 32]},\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [2, 10]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"TGFBR3\", \"FZD1\", \"JOSD1\", \"SUMF1\", \"FGFR1\", \"FGFR2\"],\n    \"other_free_text\": []\n  }\n}\n```","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}