CHST2

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).

1. 1999 High

   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

   PMID:10049591

   Open questions at the time

   • Enzymatic activity and substrate specificity not yet determined
   • Subcellular localization not directly demonstrated
   • In vivo function unknown
2. 2001 High

   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

   PMID:11310842

   Open questions at the time

   • In vivo contribution of CHST2 vs CHST1 to L-selectin ligand generation not resolved
   • Specific glycan products mediating rolling not structurally defined
3. 2009 Medium

   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

   PMID:19368826

   Open questions at the time

   • Direct transcriptional mechanism of TGF-β1 on CHST2 promoter not shown
   • Functional consequence of microglial KS production on neural repair not established
4. 2012 Medium

   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

   PMID:23238079

   Open questions at the time

   • CHST2-specific contribution not separated from CHST6 and CHST7
   • Mechanism connecting sulfated KS to apoptosis resistance unknown
5. 2018 High

   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

   PMID:30093410

   Open questions at the time

   • N-glycan substrate preferences not addressed in this study
   • Structural basis for core 2 selectivity not determined
6. 2019 High

   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

   PMID:30867513

   Open questions at the time

   • Whether critical period plasticity is functionally altered in Chst2 KO not directly tested
   • Cellular source of CHST2-dependent KS in developing brain not identified
7. 2020 High

   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

   PMID:32040930

   Open questions at the time

   • Whether Foxf2-mediated repression operates in other tissues unknown
   • Downstream functional consequences of KS/CS imbalance on palatogenesis not fully resolved
8. 2021 High

   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

   PMID:34661385

   Open questions at the time

   • In vivo relevance for Siglec-mediated immune regulation not tested
   • Whether endogenous CHST2 expression levels are sufficient to modulate Siglec binding physiologically unknown
9. 2022 High

   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

   PMID:35939855

   Open questions at the time

   • Whether arm selectivity holds for more complex branched N-glycans not tested
   • Structural basis for antennary preference not determined
10. 2023 High

    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

    PMID:37095090

    Open questions at the time

    • Whether CHST2 acts on specific glycoprotein substrates that drive metastasis unknown
    • Direct Snail binding to CHST2 promoter not shown
11. 2025 High

    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

    PMID:39836965

    Open questions at the time

    • Physiological relevance of O-mannose sulfation for Siglec signaling untested
    • Whether cis vs trans ligand balance is regulated in immune contexts unknown
12. 2025 Medium

    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

    PMID:40479051

    Open questions at the time

    • Relative contribution of CHST2 vs CHST4 to toxin binding not fully resolved
    • Whether CHST2 loss protects against typhoid intoxication in vivo not tested

• 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.
• 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