{"gene":"CHST2","run_date":"2026-04-28T17:28:52","timeline":{"discoveries":[{"year":1999,"finding":"CHST2 was identified as a novel 530-amino-acid type II transmembrane sulfotransferase expressed by human vascular endothelial cells, with a carboxyl-terminal region 45% homologous to human C6ST (CHST1) and 43% homologous to chicken C6ST; it was cloned from human vascular endothelium cDNA libraries and mapped to chromosome 3q24-q25.","method":"cDNA library screening, Northern blot analysis, chromosomal mapping","journal":"Genomics","confidence":"High","confidence_rationale":"Tier 2 — original cloning paper with multiple orthogonal methods including library screening, sequence analysis, and Northern blot; original discovery paper","pmids":["10049591"],"is_preprint":false},{"year":2001,"finding":"CHST2 (GlcNAc6ST-1) and CHST1 expressed by vascular endothelial cells contribute to the generation of functional L-selectin ligands; increased CHST1 or CHST2 expression in a cell line increased rolling leukocyte numbers, reduced rolling velocities, and enhanced leukocyte rolling under higher shear stresses in flow chamber assays.","method":"Overexpression in cell lines, in vitro flow chamber assays measuring leukocyte rolling","journal":"Journal of leukocyte biology","confidence":"High","confidence_rationale":"Tier 2 — functional overexpression with defined cellular phenotype (shear-resistant leukocyte rolling), replicated with two sulfotransferases","pmids":["11310842"],"is_preprint":false},{"year":2021,"finding":"Overexpression of CHST2 significantly enhances binding of numerous Siglecs (including CD33/Siglec-3) to cell surface glycans by sulfating GlcNAc residues; mass spectrometry-based binding assay showed that CHST2-generated 6-O-sulfo-GlcNAc on sialyllactosamine structures (Neu5Acα2-3Galβ1-4(6-O-sulfo)GlcNAc) provided ≥2-fold enhanced affinity for Siglec-3, and joint overexpression of CHST1 with CHST2 greatly enhanced CD33 and several other Siglec bindings.","method":"CHST overexpression in five cell lines, mass spectrometry-based binding assay with homogeneous Siglec-3 fragment, pharmacological glycan maturation blockade","journal":"ACS chemical biology","confidence":"High","confidence_rationale":"Tier 1-2 — in vitro biochemical binding assay with defined glycan structures, MS quantification, multiple cell lines, multiple Siglecs tested with orthogonal pharmacological controls","pmids":["34661385"],"is_preprint":false},{"year":2018,"finding":"Human GlcNAc6ST-1 (CHST2) preferentially sulfates core 2-based O-glycan structures but shows less activity on extended core 1 structures; MS/MS sulfoglycomic analysis in SW480 colon cancer cells overexpressing CHST2 revealed distinct substrate specificity compared to CHST4 (GlcNAc6ST-2) and CHST5 (GlcNAc6ST-3).","method":"Overexpression in SW480 colon cancer cells, mass spectrometry-based sulfoglycomic analysis with MS/MS sequencing","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — detailed MS/MS structural analysis of glycan products, direct substrate specificity determination","pmids":["30093410"],"is_preprint":false},{"year":2022,"finding":"Recombinant human CHST2 (GlcNAc-6-O-sulfotransferase 1) selectively sulfates the GlcNAc moiety located on the Manα1,3Man arm of biantennary N-glycans in vitro, showing high antennary preference; sulfated N-glycans produced by CHST2 can be transferred to intact IgG antibodies via chemoenzymatic Fc glycan remodeling.","method":"In vitro enzymatic sulfation assay with recombinant human CHST2, chemoenzymatic antibody glycan remodeling, glycan characterization","journal":"Bioorganic chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro enzymatic reconstitution with defined substrates, site-selective activity characterized biochemically","pmids":["35939855"],"is_preprint":false},{"year":2023,"finding":"CHST2 is induced by the transcriptional repressor Snail in breast cancer cells; CHST2 depletion inhibits breast cancer cell migration and metastasis, while CHST2 overexpression promotes cell migration and lung metastasis in nude mice; the sulfation of MECA79 antigens by CHST2 mediates this pro-metastatic effect, as blocking MECA79 antigen with specific antibodies overrides CHST2-mediated cell migration.","method":"shRNA knockdown, overexpression, nude mouse metastasis assay, MECA79 antibody blocking, sulfation inhibitor (sodium chlorate) treatment","journal":"Cell death & disease","confidence":"High","confidence_rationale":"Tier 2 — loss-of-function and gain-of-function with defined cellular and in vivo phenotypes, functional rescue with antibody blocking, confirmed with pharmacological inhibitor","pmids":["37095090"],"is_preprint":false},{"year":2025,"finding":"CHST2 is a critical host factor for hepatobiliary tropism of PltC typhoid toxin; PltC typhoid toxin binds to sulfated glycans on liver sinusoidal endothelial cells and gallbladder epithelial cells through CHST2/4-mediated sulfation, with PltC R109 residue being critical for this interaction.","method":"Functional cell binding assays, mutagenesis of bacterial PltC subunit (R109), genetic perturbation of host CHST2/4","journal":"Science advances","confidence":"Medium","confidence_rationale":"Tier 2 — direct functional evidence linking CHST2 sulfation to pathogen binding, but details of CHST2-specific contribution vs CHST4 not fully resolved","pmids":["40479051"],"is_preprint":false},{"year":2012,"finding":"Repression of CHST2 (along with CHST6 and CHST7), the N-acetylglucosamine-6-O-sulfotransferases responsible for 6-O-sulfation of GlcNAc residues in keratan sulfate, increased radiation-induced apoptosis in human Burkitt's lymphoma cells, indicating that GlcNAc 6-O-sulfation of keratan sulfate contributes to radiation resistance.","method":"siRNA-mediated knockdown of CHST2/CHST6/CHST7, radiation-induced apoptosis assay, keratan sulfate expression analysis","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 — KD with defined apoptosis phenotype, but CHST2 not separately analyzed from CHST6/7","pmids":["23238079"],"is_preprint":false},{"year":2025,"finding":"In cells expressing CHST2, N-glycans and mucin-type O-glycans both contribute to sulfated Siglec ligands for Siglec-3, -5, -8, and -15; O-mannose glycans within CHST2-expressing cells also present sulfated Siglec ligands for Siglec-3 and Siglec-8; CHST2-generated sulfated N-glycans are major trans ligands for Siglec-3 while complex mucin-type O-glycans had the largest impact on Siglec-3 cis masking.","method":"Genetic disruption of glycan biosynthesis pathways, pharmacological blockade, enzymatic treatment in CHST2-expressing cells, flow cytometry binding assays","journal":"ACS chemical biology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal genetic and pharmacological approaches systematically dissecting glycan class contributions in CHST2-expressing cells","pmids":["39836965"],"is_preprint":false},{"year":2020,"finding":"Foxf2 directly occupies the Chst2 locus and represses Chst2 expression in palatal mesenchyme; loss of Foxf2 results in ectopic Chst2 expression, with a region-specific increase in sulfated keratan sulfate and concomitant reduction in chondroitin sulfate in posterior palatal mesenchyme.","method":"ChIP-seq, RNA-seq, in situ hybridization, Foxf2 knockout mouse model","journal":"Journal of dental research","confidence":"High","confidence_rationale":"Tier 2 — ChIP-seq demonstrates direct Foxf2 occupancy at Chst2 locus; RNA-seq and ISH confirm expression changes; KO mouse shows biochemical glycan consequences","pmids":["32040930"],"is_preprint":false},{"year":2019,"finding":"GlcNAc6ST-1 (encoded by Chst2) is required for synthesis of GlcNAc-6-sulfated keratan sulfate chains in the mouse brain during the critical period of visual cortex plasticity, but not in adulthood; in adulthood, GlcNAc6ST3 (encoded by Chst5) is the major brain KS sulfotransferase expressed in oligodendrocytes.","method":"Knockout mouse analysis, R-10G anti-KS antibody immunostaining, comparison of Chst2 and Chst5 deficient mice","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with defined molecular phenotype, demonstrates developmental stage-specific role of CHST2 in KS synthesis","pmids":["30867513"],"is_preprint":false},{"year":2009,"finding":"TGF-β1 induces expression of GlcNAc6ST-1 (encoded by Chst2) in microglia after brain injury, leading to increased keratan sulfate biosynthesis; bFGF induces TGF-β1 in astrocytes, and astrocyte-conditioned medium following bFGF stimulation induces keratan sulfate production in microglia that is blocked by TGF-β1-neutralizing antibody.","method":"In vitro microglia culture with cytokine treatment, RT-PCR, TGF-β1 neutralizing antibody blocking, in vivo knife-cut brain injury model","journal":"Brain research","confidence":"Medium","confidence_rationale":"Tier 2-3 — in vitro cytokine treatment with molecular readout, confirmed with neutralizing antibody; TGF-β1→GlcNAc6ST-1 axis established","pmids":["19368826"],"is_preprint":false}],"current_model":"CHST2 (GlcNAc-6-O-sulfotransferase 1/GlcNAc6ST-1) is a Golgi-localized type II transmembrane enzyme that transfers sulfate from PAPS to the C-6 position of GlcNAc residues in glycosaminoglycans (keratan sulfate) and sialyllactosamine-containing glycans on N- and O-glycoproteins; it functions in vascular endothelial cells to generate L-selectin ligands (via MECA79-type sulfated glycans), modulates Siglec ligand strength by creating 6-sulfo-GlcNAc determinants that enhance Siglec binding, promotes breast cancer metastasis through Snail-induced upregulation and MECA79 antigen sulfation, serves as a host receptor for PltC typhoid toxin through sulfated glycan presentation, and is regulated transcriptionally by Foxf2 and TGF-β1 to control keratan sulfate and chondroitin sulfate biosynthesis in developmental and injury contexts."},"narrative":{"teleology":[{"year":1999,"claim":"Identification of CHST2 as a novel sulfotransferase in vascular endothelium established it as a member of the carbohydrate sulfotransferase family with sequence homology to C6ST/CHST1, raising the question of its specific enzymatic function and biological role.","evidence":"cDNA library screening from human vascular endothelium, Northern blot, chromosomal mapping to 3q24-q25","pmids":["10049591"],"confidence":"High","gaps":["Enzymatic activity and substrate specificity not yet determined","Subcellular localization not directly demonstrated","In vivo function unknown"]},{"year":2001,"claim":"Demonstrating that CHST2 overexpression generates functional L-selectin ligands that support shear-resistant leukocyte rolling established the first biological role for CHST2 in leukocyte trafficking.","evidence":"Overexpression in cell lines with in vitro flow chamber assays measuring rolling velocity and shear resistance","pmids":["11310842"],"confidence":"High","gaps":["In vivo contribution of CHST2 vs CHST1 to L-selectin ligand generation not resolved","Specific glycan products mediating rolling not structurally defined"]},{"year":2009,"claim":"Showing that TGF-β1 induces CHST2 expression in microglia after brain injury linked CHST2-dependent keratan sulfate biosynthesis to neuroinflammatory signaling cascades.","evidence":"In vitro microglia cytokine treatment, RT-PCR, TGF-β1 neutralizing antibody, knife-cut brain injury model","pmids":["19368826"],"confidence":"Medium","gaps":["Direct transcriptional mechanism of TGF-β1 on CHST2 promoter not shown","Functional consequence of microglial KS production on neural repair not established"]},{"year":2012,"claim":"Knockdown of GlcNAc-6-O-sulfotransferases including CHST2 sensitized lymphoma cells to radiation-induced apoptosis, linking keratan sulfate sulfation to cell survival pathways.","evidence":"siRNA knockdown of CHST2/CHST6/CHST7, apoptosis assays in Burkitt's lymphoma cells","pmids":["23238079"],"confidence":"Medium","gaps":["CHST2-specific contribution not separated from CHST6 and CHST7","Mechanism connecting sulfated KS to apoptosis resistance unknown"]},{"year":2018,"claim":"MS/MS sulfoglycomic profiling resolved CHST2's substrate preference for core 2-based O-glycans over extended core 1 structures, distinguishing it from paralogues CHST4 and CHST5.","evidence":"Overexpression in SW480 cells with mass spectrometry-based sulfoglycomic analysis","pmids":["30093410"],"confidence":"High","gaps":["N-glycan substrate preferences not addressed in this study","Structural basis for core 2 selectivity not determined"]},{"year":2019,"claim":"Knockout mouse analysis revealed that CHST2 is the principal GlcNAc-6-sulfotransferase for brain keratan sulfate synthesis during the critical period of visual cortex plasticity but is dispensable in adulthood, establishing developmental stage-specific function.","evidence":"Chst2 and Chst5 knockout mice, R-10G anti-KS immunostaining of visual cortex","pmids":["30867513"],"confidence":"High","gaps":["Whether critical period plasticity is functionally altered in Chst2 KO not directly tested","Cellular source of CHST2-dependent KS in developing brain not identified"]},{"year":2020,"claim":"ChIP-seq identification of direct Foxf2 occupancy at the Chst2 locus, with ectopic CHST2 expression and altered glycosaminoglycan composition in Foxf2 knockouts, established transcriptional repression of CHST2 as a mechanism controlling keratan sulfate vs chondroitin sulfate balance in craniofacial development.","evidence":"ChIP-seq, RNA-seq, in situ hybridization, Foxf2 knockout mouse palatal mesenchyme","pmids":["32040930"],"confidence":"High","gaps":["Whether Foxf2-mediated repression operates in other tissues unknown","Downstream functional consequences of KS/CS imbalance on palatogenesis not fully resolved"]},{"year":2021,"claim":"Demonstration that CHST2-generated 6-sulfo-GlcNAc on sialyllactosamine structures enhances binding of multiple Siglecs including CD33 expanded the functional repertoire of CHST2 from selectin ligand generation to immune-inhibitory Siglec ligand modulation.","evidence":"CHST2 overexpression in five cell lines, MS-based binding assay with recombinant Siglec-3, pharmacological glycan maturation blockade","pmids":["34661385"],"confidence":"High","gaps":["In vivo relevance for Siglec-mediated immune regulation not tested","Whether endogenous CHST2 expression levels are sufficient to modulate Siglec binding physiologically unknown"]},{"year":2022,"claim":"In vitro reconstitution with recombinant CHST2 revealed selective sulfation of the Manα1,3Man arm of biantennary N-glycans, providing the first defined antennary preference and enabling chemoenzymatic glycoengineering of antibodies.","evidence":"In vitro enzymatic sulfation with purified recombinant human CHST2, glycan characterization, IgG Fc glycan remodeling","pmids":["35939855"],"confidence":"High","gaps":["Whether arm selectivity holds for more complex branched N-glycans not tested","Structural basis for antennary preference not determined"]},{"year":2023,"claim":"Establishing that Snail induces CHST2 to drive breast cancer metastasis through MECA79 antigen sulfation linked CHST2 enzymatic activity to an EMT-associated pro-metastatic program.","evidence":"shRNA knockdown, overexpression, nude mouse lung metastasis assay, MECA79 antibody blocking, sodium chlorate treatment","pmids":["37095090"],"confidence":"High","gaps":["Whether CHST2 acts on specific glycoprotein substrates that drive metastasis unknown","Direct Snail binding to CHST2 promoter not shown"]},{"year":2025,"claim":"Systematic glycan class dissection showed that CHST2-sulfated N-glycans are the major trans ligands for Siglec-3 while sulfated mucin-type O-glycans dominate cis masking, and O-mannose glycans also carry CHST2-dependent sulfated Siglec ligands — resolving the glycan scaffold hierarchy for Siglec engagement.","evidence":"Genetic disruption of glycan pathways, pharmacological and enzymatic treatments in CHST2-expressing cells, flow cytometry","pmids":["39836965"],"confidence":"High","gaps":["Physiological relevance of O-mannose sulfation for Siglec signaling untested","Whether cis vs trans ligand balance is regulated in immune contexts unknown"]},{"year":2025,"claim":"Identification of CHST2 as a host factor for PltC typhoid toxin binding to hepatobiliary cells connected CHST2-generated sulfated glycans to bacterial pathogenesis and tissue tropism.","evidence":"Functional cell binding assays, PltC R109 mutagenesis, genetic perturbation of CHST2/4","pmids":["40479051"],"confidence":"Medium","gaps":["Relative contribution of CHST2 vs CHST4 to toxin binding not fully resolved","Whether CHST2 loss protects against typhoid intoxication in vivo not tested"]},{"year":null,"claim":"The structural basis for CHST2's antennary and core-structure selectivity remains unresolved, and whether CHST2-mediated sulfation of Siglec ligands regulates immune checkpoint signaling in vivo has not been tested.","evidence":"","pmids":[],"confidence":"High","gaps":["No crystal structure or cryo-EM structure of CHST2 available","In vivo immune phenotype of CHST2 loss with respect to Siglec-mediated signaling not characterized","Specific glycoprotein substrates in metastatic cancer not identified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,3,4]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[3,4,10]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[1,2,8]}],"complexes":[],"partners":["CHST1","SNAI1"],"other_free_text":[]},"mechanistic_narrative":"CHST2 (GlcNAc6ST-1) is a Golgi-resident type II transmembrane sulfotransferase that transfers sulfate from PAPS to the C-6 hydroxyl of N-acetylglucosamine residues on N-glycans, O-glycans, O-mannose glycans, and keratan sulfate chains, thereby generating 6-sulfo-GlcNAc determinants critical for selectin- and Siglec-mediated cell recognition [PMID:10049591, PMID:34661385, PMID:39836965]. CHST2 exhibits preferential activity toward core 2-branched O-glycans and selectively sulfates the Manα1,3Man arm of biantennary N-glycans, producing MECA79-reactive sulfated epitopes that serve as functional L-selectin ligands on vascular endothelium and as enhanced binding determinants for multiple Siglecs including CD33/Siglec-3 [PMID:30093410, PMID:35939855, PMID:11310842]. In breast cancer, Snail-induced CHST2 upregulation promotes cell migration and lung metastasis through sulfation of MECA79 antigens, while CHST2-generated sulfated glycans also serve as host receptors for PltC typhoid toxin on hepatobiliary epithelium [PMID:37095090, PMID:40479051]. CHST2 is transcriptionally regulated by Foxf2 in palatal mesenchyme and by TGF-β1 in microglia, and is required for keratan sulfate synthesis in the developing mouse brain during the critical period of visual cortex plasticity [PMID:32040930, PMID:19368826, PMID:30867513]."},"prefetch_data":{"uniprot":{"accession":"Q9Y4C5","full_name":"Carbohydrate sulfotransferase 2","aliases":["Galactose/N-acetylglucosamine/N-acetylglucosamine 6-O-sulfotransferase 2","GST-2","N-acetylglucosamine 6-O-sulfotransferase 1","GlcNAc6ST-1","Gn6ST-1"],"length_aa":530,"mass_kda":57.9,"function":"Sulfotransferase that utilizes 3'-phospho-5'-adenylyl sulfate (PAPS) as sulfonate donor to catalyze the transfer of sulfate to position 6 of non-reducing N-acetylglucosamine (GlcNAc) residues within keratan-like structures on N- and O-linked glycans and within O-linked mucin-type glycans (PubMed:11042394, PubMed:11726653, PubMed:35939855, PubMed:38034954, PubMed:9722682). Selectively transfers the sulfate group onto the terminal GlcNAc of alpha1,3-Man or alpha1,6-Man antenna of complex-type N-glycans depending on glycan composition. Only sulfates terminal GlcNAc of alpha1,3-Man antenna of G0 complex-type N-glycans. Can sulfate keratan-type N-acetyllactosamine (LacNAc) repeats generating epitopes for self versus non-self immune recognition by C-type lectins (PubMed:35939855, PubMed:38034954). Transfers the sulfate group primarily on core 2 GlcNAcbeta1-6(Galbeta1-3)GalNAcalpha-Ser/Thr and with lower efficiency on extended core 1 GlcNAcbeta1-3Galbeta1-3GalNAcalpha-Ser/Thr based O-linked glycans on peripheral node addressins (PNAds) expressed on the lumenal side of high endothelial venules (HEVs). Shares substrate specificity with CHST4 and both contribute to generate sialyl 6-sulfo Lewis X determinant (also known as MECA-79 epitope) for SELL recognition, a prerequisite for continuous lymphocyte homing into peripheral lymph nodes and antigen immune surveillance (By similarity) (PubMed:9722682). Has no activity toward alpha-linked GlcNAc moiety exposed at the non-reducing ends or to internally located GlcNAc residues (PubMed:11042394)","subcellular_location":"Golgi apparatus, trans-Golgi network membrane","url":"https://www.uniprot.org/uniprotkb/Q9Y4C5/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CHST2","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CHST2","total_profiled":1310},"omim":[{"mim_id":"604817","title":"CARBOHYDRATE SULFOTRANSFERASE 5; CHST5","url":"https://www.omim.org/entry/604817"},{"mim_id":"603798","title":"CARBOHYDRATE SULFOTRANSFERASE 2; CHST2","url":"https://www.omim.org/entry/603798"},{"mim_id":"300375","title":"CARBOHYDRATE SULFOTRANSFERASE 7; CHST7","url":"https://www.omim.org/entry/300375"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Golgi apparatus","reliability":"Supported"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":49.8}],"url":"https://www.proteinatlas.org/search/CHST2"},"hgnc":{"alias_symbol":["C6ST"],"prev_symbol":[]},"alphafold":{"accession":"Q9Y4C5","domains":[{"cath_id":"3.40.50","chopping":"171-361_384-517","consensus_level":"medium","plddt":93.1422,"start":171,"end":517}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y4C5","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y4C5-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y4C5-F1-predicted_aligned_error_v6.png","plddt_mean":77.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CHST2","jax_strain_url":"https://www.jax.org/strain/search?query=CHST2"},"sequence":{"accession":"Q9Y4C5","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y4C5.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y4C5/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y4C5"}},"corpus_meta":[{"pmid":"23774590","id":"PMC_23774590","title":"Biosynthesis and function of chondroitin sulfate.","date":"2013","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/23774590","citation_count":373,"is_preprint":false},{"pmid":"9395468","id":"PMC_9395468","title":"Developmental regulation of the sulfation profile of chondroitin sulfate chains in the chicken embryo brain.","date":"1997","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9395468","citation_count":159,"is_preprint":false},{"pmid":"15215498","id":"PMC_15215498","title":"Loss of chondroitin 6-O-sulfotransferase-1 function results in severe human chondrodysplasia with progressive spinal involvement.","date":"2004","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/15215498","citation_count":142,"is_preprint":false},{"pmid":"9405439","id":"PMC_9405439","title":"Molecular cloning and characterization of human keratan sulfate Gal-6-sulfotransferase.","date":"1997","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9405439","citation_count":122,"is_preprint":false},{"pmid":"25349438","id":"PMC_25349438","title":"Biopsy-induced inflammatory conditions improve endometrial receptivity: the mechanism of action.","date":"2014","source":"Reproduction (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/25349438","citation_count":116,"is_preprint":false},{"pmid":"7629189","id":"PMC_7629189","title":"Molecular cloning and expression of chick chondrocyte chondroitin 6-sulfotransferase.","date":"1995","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/7629189","citation_count":115,"is_preprint":false},{"pmid":"21747937","id":"PMC_21747937","title":"6-Sulphated chondroitins have a positive influence on axonal regeneration.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21747937","citation_count":88,"is_preprint":false},{"pmid":"18079434","id":"PMC_18079434","title":"Expression of multiple chondroitin/dermatan sulfotransferases in the neurogenic regions of the embryonic and adult central nervous system implies that complex chondroitin sulfates have a role in neural stem cell maintenance.","date":"2007","source":"Stem cells (Dayton, Ohio)","url":"https://pubmed.ncbi.nlm.nih.gov/18079434","citation_count":85,"is_preprint":false},{"pmid":"10781596","id":"PMC_10781596","title":"Molecular cloning and expression of a novel chondroitin 6-O-sulfotransferase.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10781596","citation_count":77,"is_preprint":false},{"pmid":"9714738","id":"PMC_9714738","title":"Molecular cloning and expression of human chondroitin 6-sulfotransferase.","date":"1998","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/9714738","citation_count":72,"is_preprint":false},{"pmid":"11696535","id":"PMC_11696535","title":"Functional analysis of the chondroitin 6-sulfotransferase gene in relation to lymphocyte subpopulations, brain development, and oversulfated chondroitin sulfates.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11696535","citation_count":65,"is_preprint":false},{"pmid":"34661385","id":"PMC_34661385","title":"Carbohydrate Sulfation As a Mechanism for Fine-Tuning Siglec Ligands.","date":"2021","source":"ACS chemical biology","url":"https://pubmed.ncbi.nlm.nih.gov/34661385","citation_count":61,"is_preprint":false},{"pmid":"26631031","id":"PMC_26631031","title":"Diagnostic marker signature for esophageal cancer from transcriptome analysis.","date":"2015","source":"Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/26631031","citation_count":58,"is_preprint":false},{"pmid":"23129769","id":"PMC_23129769","title":"Construction of a chondroitin sulfate library with defined structures and analysis of molecular interactions.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23129769","citation_count":48,"is_preprint":false},{"pmid":"9883891","id":"PMC_9883891","title":"Functional expression and genomic structure of human chondroitin 6-sulfotransferase.","date":"1998","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/9883891","citation_count":46,"is_preprint":false},{"pmid":"10049591","id":"PMC_10049591","title":"CHST1 and CHST2 sulfotransferases expressed by human vascular endothelial cells: cDNA cloning, expression, and chromosomal localization.","date":"1999","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/10049591","citation_count":45,"is_preprint":false},{"pmid":"19320654","id":"PMC_19320654","title":"Omani-type spondyloepiphyseal dysplasia with cardiac involvement caused by a missense mutation in CHST3.","date":"2009","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19320654","citation_count":44,"is_preprint":false},{"pmid":"18698629","id":"PMC_18698629","title":"Spondyloepiphyseal dysplasia, Omani type: further definition of the phenotype.","date":"2008","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/18698629","citation_count":41,"is_preprint":false},{"pmid":"26231575","id":"PMC_26231575","title":"Involvement of chondroitin 6-sulfation in temporal lobe epilepsy.","date":"2015","source":"Experimental neurology","url":"https://pubmed.ncbi.nlm.nih.gov/26231575","citation_count":41,"is_preprint":false},{"pmid":"9597547","id":"PMC_9597547","title":"Mouse chondroitin 6-sulfotransferase: molecular cloning, characterization and chromosomal mapping.","date":"1998","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/9597547","citation_count":40,"is_preprint":false},{"pmid":"8991509","id":"PMC_8991509","title":"Enzymatic sulfation of galactose residue of keratan sulfate by chondroitin 6-sulfotransferase.","date":"1996","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/8991509","citation_count":40,"is_preprint":false},{"pmid":"23880769","id":"PMC_23880769","title":"Galactose 6-O-sulfotransferases are not required for the generation of Siglec-F ligands in leukocytes or lung tissue.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23880769","citation_count":37,"is_preprint":false},{"pmid":"9147050","id":"PMC_9147050","title":"Sulfation of sialyl lactosamine oligosaccharides by chondroitin 6-sulfotransferase.","date":"1997","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/9147050","citation_count":37,"is_preprint":false},{"pmid":"29484646","id":"PMC_29484646","title":"A microbial-enzymatic strategy for producing chondroitin sulfate glycosaminoglycans.","date":"2018","source":"Biotechnology and bioengineering","url":"https://pubmed.ncbi.nlm.nih.gov/29484646","citation_count":37,"is_preprint":false},{"pmid":"11310842","id":"PMC_11310842","title":"CHST1 and CHST2 sulfotransferase expression by vascular endothelial cells regulates shear-resistant leukocyte rolling via L-selectin.","date":"2001","source":"Journal of leukocyte biology","url":"https://pubmed.ncbi.nlm.nih.gov/11310842","citation_count":35,"is_preprint":false},{"pmid":"10528213","id":"PMC_10528213","title":"L-selectin ligands expressed by human leukocytes are HECA-452 antibody-defined carbohydrate epitopes preferentially displayed by P-selectin glycoprotein ligand-1.","date":"1999","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/10528213","citation_count":35,"is_preprint":false},{"pmid":"19921088","id":"PMC_19921088","title":"Cytokine receptor-like factor 1 is highly expressed in damaged human knee osteoarthritic cartilage and involved in osteoarthritis downstream of TGF-beta.","date":"2009","source":"Calcified tissue international","url":"https://pubmed.ncbi.nlm.nih.gov/19921088","citation_count":33,"is_preprint":false},{"pmid":"23254996","id":"PMC_23254996","title":"KSGal6ST generates galactose-6-O-sulfate in high endothelial venules but does not contribute to L-selectin-dependent lymphocyte homing.","date":"2012","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/23254996","citation_count":32,"is_preprint":false},{"pmid":"11056388","id":"PMC_11056388","title":"Molecular cloning, expression, and chromosomal mapping of human chondroitin 4-sulfotransferase, whose expression pattern in human tissues is different from that of chondroitin 6-sulfotransferase.","date":"2000","source":"Journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11056388","citation_count":30,"is_preprint":false},{"pmid":"35745763","id":"PMC_35745763","title":"Pharmacogenetics and Pain Treatment with a Focus on Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and Antidepressants: A Systematic Review.","date":"2022","source":"Pharmaceutics","url":"https://pubmed.ncbi.nlm.nih.gov/35745763","citation_count":30,"is_preprint":false},{"pmid":"28649518","id":"PMC_28649518","title":"Insights in the etiopathology of galactosyltransferase II (GalT-II) deficiency from transcriptome-wide expression profiling of skin fibroblasts of two sisters with compound heterozygosity for two novel B3GALT6 mutations.","date":"2014","source":"Molecular genetics and metabolism reports","url":"https://pubmed.ncbi.nlm.nih.gov/28649518","citation_count":29,"is_preprint":false},{"pmid":"31908019","id":"PMC_31908019","title":"Expression and function of chondroitin 4-sulfate and chondroitin 6-sulfate in human glioma.","date":"2019","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/31908019","citation_count":28,"is_preprint":false},{"pmid":"18697746","id":"PMC_18697746","title":"Sulfation of the galactose residues in the glycosaminoglycan-protein linkage region by recombinant human chondroitin 6-O-sulfotransferase-1.","date":"2008","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18697746","citation_count":26,"is_preprint":false},{"pmid":"30867513","id":"PMC_30867513","title":"GlcNAc6ST3 is a keratan sulfate sulfotransferase for the protein-tyrosine phosphatase PTPRZ in the adult brain.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/30867513","citation_count":25,"is_preprint":false},{"pmid":"16495484","id":"PMC_16495484","title":"Upregulation of chondroitin 6-sulphotransferase-1 facilitates Schwann cell migration during axonal growth.","date":"2006","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/16495484","citation_count":24,"is_preprint":false},{"pmid":"19368826","id":"PMC_19368826","title":"Transforming growth factor-beta1 upregulates keratan sulfate and chondroitin sulfate biosynthesis in microglias after brain injury.","date":"2009","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/19368826","citation_count":24,"is_preprint":false},{"pmid":"9639683","id":"PMC_9639683","title":"Human chondroitin 6-sulfotransferase: cloning, gene structure, and chromosomal localization.","date":"1998","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/9639683","citation_count":22,"is_preprint":false},{"pmid":"30093410","id":"PMC_30093410","title":"Distinct substrate specificities of human GlcNAc-6-sulfotransferases revealed by mass spectrometry-based sulfoglycomic analysis.","date":"2018","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/30093410","citation_count":22,"is_preprint":false},{"pmid":"16720579","id":"PMC_16720579","title":"N-linked oligosaccharides on chondroitin 6-sulfotransferase-1 are required for production of the active enzyme, Golgi localization, and sulfotransferase activity toward keratan sulfate.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16720579","citation_count":20,"is_preprint":false},{"pmid":"26572954","id":"PMC_26572954","title":"A novel CHST3 allele associated with spondyloepiphyseal dysplasia and hearing loss in Pakistani kindred.","date":"2015","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/26572954","citation_count":18,"is_preprint":false},{"pmid":"25521733","id":"PMC_25521733","title":"Single nucleotide polymorphism markers for low-dose aspirin-associated peptic ulcer and ulcer bleeding.","date":"2014","source":"Journal of gastroenterology and hepatology","url":"https://pubmed.ncbi.nlm.nih.gov/25521733","citation_count":17,"is_preprint":false},{"pmid":"23238079","id":"PMC_23238079","title":"Sulfation of keratan sulfate proteoglycan reduces radiation-induced apoptosis in human Burkitt's lymphoma cell lines.","date":"2012","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/23238079","citation_count":17,"is_preprint":false},{"pmid":"35939855","id":"PMC_35939855","title":"Site-selective sulfation of N-glycans by human GlcNAc-6-O-sulfotransferase 1 (CHST2) and chemoenzymatic synthesis of sulfated antibody glycoforms.","date":"2022","source":"Bioorganic chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/35939855","citation_count":15,"is_preprint":false},{"pmid":"11829137","id":"PMC_11829137","title":"Catalog of 77 single-nucleotide polymorphisms (SNPs) in the carbohydrate sulfotransferase 1 (CHST1) and carbohydrate sulfotransferase 3 (CHST3) genes.","date":"2002","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11829137","citation_count":15,"is_preprint":false},{"pmid":"18237557","id":"PMC_18237557","title":"Expression of sulfotransferases involved in the biosynthesis of chondroitin sulfate E in the bone marrow derived mast cells.","date":"2008","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/18237557","citation_count":15,"is_preprint":false},{"pmid":"33495490","id":"PMC_33495490","title":"Chondroitin 6-sulfate represses keratinocyte proliferation in mouse skin, which is associated with psoriasis.","date":"2021","source":"Communications biology","url":"https://pubmed.ncbi.nlm.nih.gov/33495490","citation_count":14,"is_preprint":false},{"pmid":"20001860","id":"PMC_20001860","title":"Proteomic analysis of bone tissues of patients with osteonecrosis of the femoral head.","date":"2009","source":"Omics : a journal of integrative biology","url":"https://pubmed.ncbi.nlm.nih.gov/20001860","citation_count":12,"is_preprint":false},{"pmid":"28044229","id":"PMC_28044229","title":"Genetic Biomarker Prevalence Is Similar in Fecal Immunochemical Test Positive and Negative Colorectal Cancer Tissue.","date":"2017","source":"Digestive diseases and sciences","url":"https://pubmed.ncbi.nlm.nih.gov/28044229","citation_count":11,"is_preprint":false},{"pmid":"35267472","id":"PMC_35267472","title":"Preliminary Study on the Sequencing of Whole Genomic Methylation and Transcriptome-Related Genes in Thyroid Carcinoma.","date":"2022","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/35267472","citation_count":11,"is_preprint":false},{"pmid":"27753269","id":"PMC_27753269","title":"Spondyloepiphyseal dysplasia Omani type: CHST3 mutation spectrum and phenotypes in three Indian families.","date":"2016","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/27753269","citation_count":11,"is_preprint":false},{"pmid":"36189308","id":"PMC_36189308","title":"Tumor necrosis factor receptor regulation of peripheral node addressin biosynthetic components in tumor endothelial cells.","date":"2022","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/36189308","citation_count":10,"is_preprint":false},{"pmid":"39836965","id":"PMC_39836965","title":"Understanding the Glycosylation Pathways Involved in the Biosynthesis of the Sulfated Glycan Ligands for Siglecs.","date":"2025","source":"ACS chemical biology","url":"https://pubmed.ncbi.nlm.nih.gov/39836965","citation_count":10,"is_preprint":false},{"pmid":"35221933","id":"PMC_35221933","title":"Beta3Gn-T7 Is a Keratan Sulfate β1,3 N-Acetylglucosaminyltransferase in the Adult Brain.","date":"2022","source":"Frontiers in neuroanatomy","url":"https://pubmed.ncbi.nlm.nih.gov/35221933","citation_count":10,"is_preprint":false},{"pmid":"32040930","id":"PMC_32040930","title":"Genome-wide Identification of Foxf2 Target Genes in Palate Development.","date":"2020","source":"Journal of dental research","url":"https://pubmed.ncbi.nlm.nih.gov/32040930","citation_count":9,"is_preprint":false},{"pmid":"36998246","id":"PMC_36998246","title":"Tissue-specific expression of carbohydrate sulfotransferases drives keratan sulfate biosynthesis in the notochord and otic vesicles of Xenopus embryos.","date":"2023","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/36998246","citation_count":8,"is_preprint":false},{"pmid":"37095090","id":"PMC_37095090","title":"CHST2-mediated sulfation of MECA79 antigens is critical for breast cancer cell migration and metastasis.","date":"2023","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/37095090","citation_count":6,"is_preprint":false},{"pmid":"25298188","id":"PMC_25298188","title":"Chondroitin 6-O-sulfotransferases are required for morphogenesis of the notochord in the ascidian embryo.","date":"2014","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/25298188","citation_count":6,"is_preprint":false},{"pmid":"33775699","id":"PMC_33775699","title":"Development and validation of a novel glycolysis-related risk signature for predicting survival in pancreatic adenocarcinoma.","date":"2021","source":"Clinica chimica acta; international journal of clinical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/33775699","citation_count":6,"is_preprint":false},{"pmid":"32652010","id":"PMC_32652010","title":"Reconstruction of the Carbohydrate 6-O Sulfotransferase Gene Family Evolution in Vertebrates Reveals Novel Member, CHST16, Lost in Amniotes.","date":"2020","source":"Genome biology and evolution","url":"https://pubmed.ncbi.nlm.nih.gov/32652010","citation_count":5,"is_preprint":false},{"pmid":"37064094","id":"PMC_37064094","title":"Single-cell RNA sequencing depicts metabolic changes in children with aplastic anemia.","date":"2023","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/37064094","citation_count":3,"is_preprint":false},{"pmid":"39063109","id":"PMC_39063109","title":"Discovery of a Therapeutic Agent for Glioblastoma Using a Systems Biology-Based Drug Repositioning Approach.","date":"2024","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/39063109","citation_count":3,"is_preprint":false},{"pmid":"35889417","id":"PMC_35889417","title":"Complementary Role of GlcNAc6ST2 and GlcNAc6ST3 in Synthesis of CL40-Reactive Sialylated and Sulfated Glycans in the Mouse Pleural Mesothelium.","date":"2022","source":"Molecules (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/35889417","citation_count":2,"is_preprint":false},{"pmid":"39596612","id":"PMC_39596612","title":"Metabolic Transcriptional Activation in Ulcerative Colitis Identified Through scRNA-seq Analysis.","date":"2024","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/39596612","citation_count":2,"is_preprint":false},{"pmid":"40479051","id":"PMC_40479051","title":"Molecular basis of the hepatobiliary tropism of typhoid toxin promoting Salmonella pathogenicity.","date":"2025","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/40479051","citation_count":1,"is_preprint":false},{"pmid":"39609348","id":"PMC_39609348","title":"Comprehensive Analysis of Sialylation-Related Gene Profiles and Their Impact on the Immune Microenvironment in Periodontitis.","date":"2024","source":"Inflammation","url":"https://pubmed.ncbi.nlm.nih.gov/39609348","citation_count":0,"is_preprint":false},{"pmid":"41638162","id":"PMC_41638162","title":"Exosome-related lactylation gene signature defines diagnostic biomarkers of periodontitis through integrative bulk and single-cell transcriptomics.","date":"2025","source":"Archives of oral biology","url":"https://pubmed.ncbi.nlm.nih.gov/41638162","citation_count":0,"is_preprint":false},{"pmid":"21485569","id":"PMC_21485569","title":"[High throughout proteomic analysis of non-traumatic osteonecrosis of the femoral head].","date":"2011","source":"Zhongguo gu shang = China journal of orthopaedics and traumatology","url":"https://pubmed.ncbi.nlm.nih.gov/21485569","citation_count":0,"is_preprint":false},{"pmid":"41730709","id":"PMC_41730709","title":"Biomanufacturing of Therapeutically Relevant Chondroitin Sulfate C via Engineered Microbes.","date":"2026","source":"ACS synthetic biology","url":"https://pubmed.ncbi.nlm.nih.gov/41730709","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":37078,"output_tokens":3368,"usd":0.080877},"stage2":{"model":"claude-opus-4-6","input_tokens":6740,"output_tokens":3021,"usd":0.163837},"total_usd":0.244714,"stage1_batch_id":"msgbatch_011kfMfE81o6CTcyhVUqumuW","stage2_batch_id":"msgbatch_01DTputS6WNkH745x1nVSoBo","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"CHST2 was identified as a novel 530-amino-acid type II transmembrane sulfotransferase expressed by human vascular endothelial cells, with a carboxyl-terminal region 45% homologous to human C6ST (CHST1) and 43% homologous to chicken C6ST; it was cloned from human vascular endothelium cDNA libraries and mapped to chromosome 3q24-q25.\",\n      \"method\": \"cDNA library screening, Northern blot analysis, chromosomal mapping\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — original cloning paper with multiple orthogonal methods including library screening, sequence analysis, and Northern blot; original discovery paper\",\n      \"pmids\": [\"10049591\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"CHST2 (GlcNAc6ST-1) and CHST1 expressed by vascular endothelial cells contribute to the generation of functional L-selectin ligands; increased CHST1 or CHST2 expression in a cell line increased rolling leukocyte numbers, reduced rolling velocities, and enhanced leukocyte rolling under higher shear stresses in flow chamber assays.\",\n      \"method\": \"Overexpression in cell lines, in vitro flow chamber assays measuring leukocyte rolling\",\n      \"journal\": \"Journal of leukocyte biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — functional overexpression with defined cellular phenotype (shear-resistant leukocyte rolling), replicated with two sulfotransferases\",\n      \"pmids\": [\"11310842\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Overexpression of CHST2 significantly enhances binding of numerous Siglecs (including CD33/Siglec-3) to cell surface glycans by sulfating GlcNAc residues; mass spectrometry-based binding assay showed that CHST2-generated 6-O-sulfo-GlcNAc on sialyllactosamine structures (Neu5Acα2-3Galβ1-4(6-O-sulfo)GlcNAc) provided ≥2-fold enhanced affinity for Siglec-3, and joint overexpression of CHST1 with CHST2 greatly enhanced CD33 and several other Siglec bindings.\",\n      \"method\": \"CHST overexpression in five cell lines, mass spectrometry-based binding assay with homogeneous Siglec-3 fragment, pharmacological glycan maturation blockade\",\n      \"journal\": \"ACS chemical biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro biochemical binding assay with defined glycan structures, MS quantification, multiple cell lines, multiple Siglecs tested with orthogonal pharmacological controls\",\n      \"pmids\": [\"34661385\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Human GlcNAc6ST-1 (CHST2) preferentially sulfates core 2-based O-glycan structures but shows less activity on extended core 1 structures; MS/MS sulfoglycomic analysis in SW480 colon cancer cells overexpressing CHST2 revealed distinct substrate specificity compared to CHST4 (GlcNAc6ST-2) and CHST5 (GlcNAc6ST-3).\",\n      \"method\": \"Overexpression in SW480 colon cancer cells, mass spectrometry-based sulfoglycomic analysis with MS/MS sequencing\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — detailed MS/MS structural analysis of glycan products, direct substrate specificity determination\",\n      \"pmids\": [\"30093410\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Recombinant human CHST2 (GlcNAc-6-O-sulfotransferase 1) selectively sulfates the GlcNAc moiety located on the Manα1,3Man arm of biantennary N-glycans in vitro, showing high antennary preference; sulfated N-glycans produced by CHST2 can be transferred to intact IgG antibodies via chemoenzymatic Fc glycan remodeling.\",\n      \"method\": \"In vitro enzymatic sulfation assay with recombinant human CHST2, chemoenzymatic antibody glycan remodeling, glycan characterization\",\n      \"journal\": \"Bioorganic chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro enzymatic reconstitution with defined substrates, site-selective activity characterized biochemically\",\n      \"pmids\": [\"35939855\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CHST2 is induced by the transcriptional repressor Snail in breast cancer cells; CHST2 depletion inhibits breast cancer cell migration and metastasis, while CHST2 overexpression promotes cell migration and lung metastasis in nude mice; the sulfation of MECA79 antigens by CHST2 mediates this pro-metastatic effect, as blocking MECA79 antigen with specific antibodies overrides CHST2-mediated cell migration.\",\n      \"method\": \"shRNA knockdown, overexpression, nude mouse metastasis assay, MECA79 antibody blocking, sulfation inhibitor (sodium chlorate) treatment\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function and gain-of-function with defined cellular and in vivo phenotypes, functional rescue with antibody blocking, confirmed with pharmacological inhibitor\",\n      \"pmids\": [\"37095090\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CHST2 is a critical host factor for hepatobiliary tropism of PltC typhoid toxin; PltC typhoid toxin binds to sulfated glycans on liver sinusoidal endothelial cells and gallbladder epithelial cells through CHST2/4-mediated sulfation, with PltC R109 residue being critical for this interaction.\",\n      \"method\": \"Functional cell binding assays, mutagenesis of bacterial PltC subunit (R109), genetic perturbation of host CHST2/4\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct functional evidence linking CHST2 sulfation to pathogen binding, but details of CHST2-specific contribution vs CHST4 not fully resolved\",\n      \"pmids\": [\"40479051\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Repression of CHST2 (along with CHST6 and CHST7), the N-acetylglucosamine-6-O-sulfotransferases responsible for 6-O-sulfation of GlcNAc residues in keratan sulfate, increased radiation-induced apoptosis in human Burkitt's lymphoma cells, indicating that GlcNAc 6-O-sulfation of keratan sulfate contributes to radiation resistance.\",\n      \"method\": \"siRNA-mediated knockdown of CHST2/CHST6/CHST7, radiation-induced apoptosis assay, keratan sulfate expression analysis\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — KD with defined apoptosis phenotype, but CHST2 not separately analyzed from CHST6/7\",\n      \"pmids\": [\"23238079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In cells expressing CHST2, N-glycans and mucin-type O-glycans both contribute to sulfated Siglec ligands for Siglec-3, -5, -8, and -15; O-mannose glycans within CHST2-expressing cells also present sulfated Siglec ligands for Siglec-3 and Siglec-8; CHST2-generated sulfated N-glycans are major trans ligands for Siglec-3 while complex mucin-type O-glycans had the largest impact on Siglec-3 cis masking.\",\n      \"method\": \"Genetic disruption of glycan biosynthesis pathways, pharmacological blockade, enzymatic treatment in CHST2-expressing cells, flow cytometry binding assays\",\n      \"journal\": \"ACS chemical biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal genetic and pharmacological approaches systematically dissecting glycan class contributions in CHST2-expressing cells\",\n      \"pmids\": [\"39836965\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Foxf2 directly occupies the Chst2 locus and represses Chst2 expression in palatal mesenchyme; loss of Foxf2 results in ectopic Chst2 expression, with a region-specific increase in sulfated keratan sulfate and concomitant reduction in chondroitin sulfate in posterior palatal mesenchyme.\",\n      \"method\": \"ChIP-seq, RNA-seq, in situ hybridization, Foxf2 knockout mouse model\",\n      \"journal\": \"Journal of dental research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — ChIP-seq demonstrates direct Foxf2 occupancy at Chst2 locus; RNA-seq and ISH confirm expression changes; KO mouse shows biochemical glycan consequences\",\n      \"pmids\": [\"32040930\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GlcNAc6ST-1 (encoded by Chst2) is required for synthesis of GlcNAc-6-sulfated keratan sulfate chains in the mouse brain during the critical period of visual cortex plasticity, but not in adulthood; in adulthood, GlcNAc6ST3 (encoded by Chst5) is the major brain KS sulfotransferase expressed in oligodendrocytes.\",\n      \"method\": \"Knockout mouse analysis, R-10G anti-KS antibody immunostaining, comparison of Chst2 and Chst5 deficient mice\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with defined molecular phenotype, demonstrates developmental stage-specific role of CHST2 in KS synthesis\",\n      \"pmids\": [\"30867513\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"TGF-β1 induces expression of GlcNAc6ST-1 (encoded by Chst2) in microglia after brain injury, leading to increased keratan sulfate biosynthesis; bFGF induces TGF-β1 in astrocytes, and astrocyte-conditioned medium following bFGF stimulation induces keratan sulfate production in microglia that is blocked by TGF-β1-neutralizing antibody.\",\n      \"method\": \"In vitro microglia culture with cytokine treatment, RT-PCR, TGF-β1 neutralizing antibody blocking, in vivo knife-cut brain injury model\",\n      \"journal\": \"Brain research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — in vitro cytokine treatment with molecular readout, confirmed with neutralizing antibody; TGF-β1→GlcNAc6ST-1 axis established\",\n      \"pmids\": [\"19368826\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CHST2 (GlcNAc-6-O-sulfotransferase 1/GlcNAc6ST-1) is a Golgi-localized type II transmembrane enzyme that transfers sulfate from PAPS to the C-6 position of GlcNAc residues in glycosaminoglycans (keratan sulfate) and sialyllactosamine-containing glycans on N- and O-glycoproteins; it functions in vascular endothelial cells to generate L-selectin ligands (via MECA79-type sulfated glycans), modulates Siglec ligand strength by creating 6-sulfo-GlcNAc determinants that enhance Siglec binding, promotes breast cancer metastasis through Snail-induced upregulation and MECA79 antigen sulfation, serves as a host receptor for PltC typhoid toxin through sulfated glycan presentation, and is regulated transcriptionally by Foxf2 and TGF-β1 to control keratan sulfate and chondroitin sulfate biosynthesis in developmental and injury contexts.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"CHST2 (GlcNAc6ST-1) is a Golgi-resident type II transmembrane sulfotransferase that transfers sulfate from PAPS to the C-6 hydroxyl of N-acetylglucosamine residues on N-glycans, O-glycans, O-mannose glycans, and keratan sulfate chains, thereby generating 6-sulfo-GlcNAc determinants critical for selectin- and Siglec-mediated cell recognition [PMID:10049591, PMID:34661385, PMID:39836965]. CHST2 exhibits preferential activity toward core 2-branched O-glycans and selectively sulfates the Manα1,3Man arm of biantennary N-glycans, producing MECA79-reactive sulfated epitopes that serve as functional L-selectin ligands on vascular endothelium and as enhanced binding determinants for multiple Siglecs including CD33/Siglec-3 [PMID:30093410, PMID:35939855, PMID:11310842]. In breast cancer, Snail-induced CHST2 upregulation promotes cell migration and lung metastasis through sulfation of MECA79 antigens, while CHST2-generated sulfated glycans also serve as host receptors for PltC typhoid toxin on hepatobiliary epithelium [PMID:37095090, PMID:40479051]. CHST2 is transcriptionally regulated by Foxf2 in palatal mesenchyme and by TGF-β1 in microglia, and is required for keratan sulfate synthesis in the developing mouse brain during the critical period of visual cortex plasticity [PMID:32040930, PMID:19368826, PMID:30867513].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Identification of CHST2 as a novel sulfotransferase in vascular endothelium established it as a member of the carbohydrate sulfotransferase family with sequence homology to C6ST/CHST1, raising the question of its specific enzymatic function and biological role.\",\n      \"evidence\": \"cDNA library screening from human vascular endothelium, Northern blot, chromosomal mapping to 3q24-q25\",\n      \"pmids\": [\"10049591\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Enzymatic activity and substrate specificity not yet determined\", \"Subcellular localization not directly demonstrated\", \"In vivo function unknown\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Demonstrating that CHST2 overexpression generates functional L-selectin ligands that support shear-resistant leukocyte rolling established the first biological role for CHST2 in leukocyte trafficking.\",\n      \"evidence\": \"Overexpression in cell lines with in vitro flow chamber assays measuring rolling velocity and shear resistance\",\n      \"pmids\": [\"11310842\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo contribution of CHST2 vs CHST1 to L-selectin ligand generation not resolved\", \"Specific glycan products mediating rolling not structurally defined\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Showing that TGF-β1 induces CHST2 expression in microglia after brain injury linked CHST2-dependent keratan sulfate biosynthesis to neuroinflammatory signaling cascades.\",\n      \"evidence\": \"In vitro microglia cytokine treatment, RT-PCR, TGF-β1 neutralizing antibody, knife-cut brain injury model\",\n      \"pmids\": [\"19368826\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct transcriptional mechanism of TGF-β1 on CHST2 promoter not shown\", \"Functional consequence of microglial KS production on neural repair not established\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Knockdown of GlcNAc-6-O-sulfotransferases including CHST2 sensitized lymphoma cells to radiation-induced apoptosis, linking keratan sulfate sulfation to cell survival pathways.\",\n      \"evidence\": \"siRNA knockdown of CHST2/CHST6/CHST7, apoptosis assays in Burkitt's lymphoma cells\",\n      \"pmids\": [\"23238079\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"CHST2-specific contribution not separated from CHST6 and CHST7\", \"Mechanism connecting sulfated KS to apoptosis resistance unknown\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"MS/MS sulfoglycomic profiling resolved CHST2's substrate preference for core 2-based O-glycans over extended core 1 structures, distinguishing it from paralogues CHST4 and CHST5.\",\n      \"evidence\": \"Overexpression in SW480 cells with mass spectrometry-based sulfoglycomic analysis\",\n      \"pmids\": [\"30093410\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"N-glycan substrate preferences not addressed in this study\", \"Structural basis for core 2 selectivity not determined\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Knockout mouse analysis revealed that CHST2 is the principal GlcNAc-6-sulfotransferase for brain keratan sulfate synthesis during the critical period of visual cortex plasticity but is dispensable in adulthood, establishing developmental stage-specific function.\",\n      \"evidence\": \"Chst2 and Chst5 knockout mice, R-10G anti-KS immunostaining of visual cortex\",\n      \"pmids\": [\"30867513\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether critical period plasticity is functionally altered in Chst2 KO not directly tested\", \"Cellular source of CHST2-dependent KS in developing brain not identified\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"ChIP-seq identification of direct Foxf2 occupancy at the Chst2 locus, with ectopic CHST2 expression and altered glycosaminoglycan composition in Foxf2 knockouts, established transcriptional repression of CHST2 as a mechanism controlling keratan sulfate vs chondroitin sulfate balance in craniofacial development.\",\n      \"evidence\": \"ChIP-seq, RNA-seq, in situ hybridization, Foxf2 knockout mouse palatal mesenchyme\",\n      \"pmids\": [\"32040930\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Foxf2-mediated repression operates in other tissues unknown\", \"Downstream functional consequences of KS/CS imbalance on palatogenesis not fully resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstration that CHST2-generated 6-sulfo-GlcNAc on sialyllactosamine structures enhances binding of multiple Siglecs including CD33 expanded the functional repertoire of CHST2 from selectin ligand generation to immune-inhibitory Siglec ligand modulation.\",\n      \"evidence\": \"CHST2 overexpression in five cell lines, MS-based binding assay with recombinant Siglec-3, pharmacological glycan maturation blockade\",\n      \"pmids\": [\"34661385\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance for Siglec-mediated immune regulation not tested\", \"Whether endogenous CHST2 expression levels are sufficient to modulate Siglec binding physiologically unknown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"In vitro reconstitution with recombinant CHST2 revealed selective sulfation of the Manα1,3Man arm of biantennary N-glycans, providing the first defined antennary preference and enabling chemoenzymatic glycoengineering of antibodies.\",\n      \"evidence\": \"In vitro enzymatic sulfation with purified recombinant human CHST2, glycan characterization, IgG Fc glycan remodeling\",\n      \"pmids\": [\"35939855\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether arm selectivity holds for more complex branched N-glycans not tested\", \"Structural basis for antennary preference not determined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Establishing that Snail induces CHST2 to drive breast cancer metastasis through MECA79 antigen sulfation linked CHST2 enzymatic activity to an EMT-associated pro-metastatic program.\",\n      \"evidence\": \"shRNA knockdown, overexpression, nude mouse lung metastasis assay, MECA79 antibody blocking, sodium chlorate treatment\",\n      \"pmids\": [\"37095090\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CHST2 acts on specific glycoprotein substrates that drive metastasis unknown\", \"Direct Snail binding to CHST2 promoter not shown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Systematic glycan class dissection showed that CHST2-sulfated N-glycans are the major trans ligands for Siglec-3 while sulfated mucin-type O-glycans dominate cis masking, and O-mannose glycans also carry CHST2-dependent sulfated Siglec ligands — resolving the glycan scaffold hierarchy for Siglec engagement.\",\n      \"evidence\": \"Genetic disruption of glycan pathways, pharmacological and enzymatic treatments in CHST2-expressing cells, flow cytometry\",\n      \"pmids\": [\"39836965\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological relevance of O-mannose sulfation for Siglec signaling untested\", \"Whether cis vs trans ligand balance is regulated in immune contexts unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identification of CHST2 as a host factor for PltC typhoid toxin binding to hepatobiliary cells connected CHST2-generated sulfated glycans to bacterial pathogenesis and tissue tropism.\",\n      \"evidence\": \"Functional cell binding assays, PltC R109 mutagenesis, genetic perturbation of CHST2/4\",\n      \"pmids\": [\"40479051\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relative contribution of CHST2 vs CHST4 to toxin binding not fully resolved\", \"Whether CHST2 loss protects against typhoid intoxication in vivo not tested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis for CHST2's antennary and core-structure selectivity remains unresolved, and whether CHST2-mediated sulfation of Siglec ligands regulates immune checkpoint signaling in vivo has not been tested.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal structure or cryo-EM structure of CHST2 available\", \"In vivo immune phenotype of CHST2 loss with respect to Siglec-mediated signaling not characterized\", \"Specific glycoprotein substrates in metastatic cancer not identified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [3, 4, 10]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [1, 2, 8]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"CHST1\",\n      \"SNAI1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}