SULT2B1

SULT2B1 is a cytosolic hydroxysteroid sulfotransferase that catalyzes the sulfonation of 3β-hydroxysteroids, encoded by a single gene that produces two isoforms via alternative transcription initiation and 5'-exon splicing: SULT2B1b, which preferentially sulfates cholesterol, and SULT2B1a, which preferentially sulfates pregnenolone (PMID:9799594, PMID:12145317, PMID:12639899). The distinct N-terminal sequence of SULT2B1b — specifically isoleucines at positions 21 and 23 — confers its cholesterol sulfotransferase activity, while a proline-rich C-terminal extension is dispensable for catalysis but required for protein stability (PMID:12145317, PMID:17496163). The principal product, cholesterol sulfate, mediates most downstream physiology: SULT2B1 supplies epidermal cholesterol sulfate and restrains keratinocyte proliferation, and biallelic loss-of-function mutations cause autosomal-recessive congenital ichthyosis (PMID:28575648). Cholesterol sulfate generated by SULT2B1 functions as an endogenous inhibitor of DOCK2-driven Rac activation, an axis that suppresses CD8+ T-cell exhaustion in hepatocellular carcinoma and limits neutrophil-driven psoriatic skin inflammation (PMID:36626623, PMID:41181147). In macrophages, SULT2B1-dependent sterol sulfation tunes inflammatory polarization through AMPK-CREB signaling and through nuclear oxysterol/LXR-ABCA1/G1 control of cholesterol efflux, influencing ischemic stroke, choroidal neovascularization, and atherosclerosis (PMID:34815805, PMID:37550000, PMID:38286358). Beyond its sterol-sulfating role, SULT2B1 protein physically engages metabolic and signaling effectors — AKT and PKM2 to drive mTORC1 signaling and glycolysis, and SCD1 to support lipid metabolism — promoting proliferation and metastasis in gastrointestinal cancers, where it is transcriptionally induced by ETV4, SMC1A, and TGF-β1 (PMID:38372484, PMID:39639836, PMID:39623433).

1. 1998 High

   Established that a single SULT2B1 gene generates two hydroxysteroid sulfotransferase isoforms with shared DHEA-sulfating but distinct substrate boundaries, defining the gene's basic architecture.

   Evidence cDNA cloning, COS-1 expression and enzymatic assays, Northern blot, genomic mapping

   PMID:9799594

   Open questions at the time

   • Physiological substrate preferences of each isoform not yet resolved
   • Tissue-specific isoform deployment not yet mapped
2. 2001 Medium

   Refined the catalytic profile, showing both isoforms efficiently sulfonate 3β-hydroxysteroids and dihydrotestosterone, with expression in reproductive tissues.

   Evidence In vitro kinetic assays and tissue expression analysis

   PMID:11594786

   Open questions at the time

   • Single-study characterization without independent replication
   • In vivo relevance of DHT sulfation unestablished
3. 2002 High

   Resolved the isoform functional dichotomy and its structural basis, attributing cholesterol sulfotransferase activity of SULT2B1b to N-terminal isoleucines 21/23 and showing the C-terminal extension is dispensable for catalysis.

   Evidence Deletion analysis, site-directed mutagenesis, enzymatic assays

   PMID:12145317

   Open questions at the time

   • Structural mechanism by which Ile21/23 enable cholesterol binding not solved
   • Function of the C-terminal extension not yet defined
4. 2003 Medium

   Confirmed the conserved isoform architecture in mouse and mapped tissue specialization — SULT2B1a in brain/spinal cord, SULT2B1b in skin — linking each isoform's activity to its dominant tissue.

   Evidence cDNA cloning, gene structure analysis, real-time RT-PCR, enzymatic characterization in mouse

   PMID:12639899

   Open questions at the time

   • Functional consequence of brain pregnenolone sulfation not tested
   • Causal link of skin SULT2B1b to barrier function not yet shown here
5. 2007 Medium

   Defined the C-terminal proline-rich domain as a stability determinant and catalogued allozyme variation, showing coding SNPs retain most activity but truncation causes aggregation and degradation.

   Evidence Mammalian expression, allozyme activity assays, protein stability assessment

   PMID:17496163

   Open questions at the time

   • Physiological impact of allozyme variants in vivo unknown
   • Mechanism of aggregate formation not characterized
6. 2013 Low

   Reported nuclear localization of SULT2B1b linked to C-terminal serine phosphorylation, raising the possibility of regulated subcellular partitioning.

   Evidence Tissue fractionation and phosphorylation analysis summarized in review

   PMID:24020383

   Open questions at the time

   • Primary experimental methods not detailed; not independently confirmed
   • Functional role of nuclear pool undefined
   • Phosphosite not mapped
7. 2017 High

   Established SULT2B1 as a disease gene, showing loss-of-function causes autosomal-recessive congenital ichthyosis through loss of epidermal cholesterol sulfate and unchecked keratinocyte proliferation.

   Evidence Whole-exome sequencing, patient keratinocytes, 3D organotypic culture, TLC of cholesterol metabolites

   PMID:28575648

   Open questions at the time

   • Molecular signaling from cholesterol sulfate loss to proliferation not fully defined
   • Genotype-phenotype correlation across variants incomplete
8. 2021 High

   Linked SULT2B1-derived cholesterol sulfate to anti-inflammatory macrophage programming via AMPK-CREB and NADPH/ROS control, with consequences for ischemic stroke severity.

   Evidence Sult2b1 KO mice, MCAO model, bone marrow transplant, monocyte depletion/adoptive transfer, CyTOF, BMDM assays

   PMID:34815805

   Open questions at the time

   • Direct molecular target of cholesterol sulfate upstream of AMPK not identified
   • Relevance to human stroke untested
9. 2023 Medium

   Identified the SULT2B1-cholesterol sulfate-DOCK2 axis, showing tumor-derived cholesterol sulfate suppresses DOCK2 activity to promote CD8+ T-cell exhaustion in HCC.

   Evidence Quasi-targeted metabolomics, CyTOF, RNA-seq, mouse HCC models, molecular docking

   PMID:36626623

   Open questions at the time

   • Direct biochemical inhibition of DOCK2 by cholesterol sulfate not demonstrated in this study
   • Binding mode beyond docking simulation unconfirmed
10. 2023 Medium

    Extended SULT2B1's macrophage role to LXR-controlled cholesterol efflux, showing its loss activates LXR-ABCA1/G1 to reduce M2 polarization and pathological choroidal neovascularization.

    Evidence Sult2b1 KO mice, CNV model, macrophage polarization assays, LXR inhibitor GSK2033

    PMID:37550000

    Open questions at the time

    • Identity of the LXR-activating sterol ligand altered by SULT2B1 not pinned down
    • Whether the same axis operates in human AMD untested
11. 2024 Medium

    Revealed a non-sulfotransferase, protein-interaction role for SULT2B1 in cancer, where it binds AKT, PKM2 and SCD1 to drive mTORC1 signaling, glycolysis and lipid metabolism.

    Evidence IP, GST pull-down, immunofluorescence, ChIP, autophagy reporter, orthotopic colon cancer models

    PMID:38372484 PMID:39623433

    Open questions at the time

    • Whether catalytic activity is required for these interactions unknown
    • Direct binding interfaces and stoichiometry not mapped
    • Reciprocal validation of SCD1 interaction limited
12. 2024 Medium

    Placed SULT2B1 under transcriptional control of oncogenic/exosomal inputs, identifying ETV4 and SMC1A as activators that couple SULT2B1 induction to HCC and colon cancer progression.

    Evidence Dual-luciferase reporter, ChIP, exosome co-culture, xenograft and orthotopic models

    PMID:38372484 PMID:39639836

    Open questions at the time

    • Endogenous signals controlling these transcription factors in tumors unclear
    • Single-lab findings without independent replication
13. 2024 Medium

    Connected SULT2B1 to nuclear oxysterol (25HC3S)-LXR signaling and a LncRNA gga3-204/SMAD4/Smad7 cascade that restrains NF-κB and macrophage inflammation in atherosclerosis.

    Evidence Sult2b1 knockdown in mouse AS model, nuclear fractionation, LncRNA expression analysis, in vivo/in vitro functional assays

    PMID:38286358

    Open questions at the time

    • Direct molecular link between 25HC3S and gga3-204 transcription not established
    • Human relevance untested
14. 2025 High

    Demonstrated in vivo epistasis confirming cholesterol sulfate as an endogenous DOCK2-Rac inhibitor in skin, where Sult2b1 loss worsens psoriatic dermatitis rescued by DOCK2 deletion or neutrophil depletion.

    Evidence Sult2b1 KO mice, imiquimod psoriasis model, Dock2 genetic deletion, neutrophil-depleting antibody, CS measurement, keratinocyte assays

    PMID:41181147

    Open questions at the time

    • Direct biochemical inhibition of DOCK2 GEF activity by cholesterol sulfate not reconstituted
    • Threshold concentrations for in vivo inhibition unclear
15. 2025 Low

    Implicated SULT2B1 induction in cholangiocyte EMT via Wnt/β-catenin/MMP7 signaling downstream of TGF-β1.

    Evidence TGF-β1 treatment of bile duct epithelial cells, SULT2B1 silencing, pathway immunoblotting

    PMID:41402642

    Open questions at the time

    • Single cell-line model with pathway inferred from inhibitors; no direct biochemical mechanism
    • Whether sulfotransferase activity is required not tested

• How a single sulfotransferase product (cholesterol sulfate) is decoded into distinct, sometimes opposing cell-type-specific outputs — and whether SULT2B1's catalytic and protein-scaffolding (AKT/PKM2/SCD1) functions are mechanistically separable — remains unresolved.
• No structure of SULT2B1 bound to cholesterol or to AKT/PKM2/SCD1
• Direct biochemical demonstration of DOCK2 inhibition by cholesterol sulfate lacking
• Whether enzymatic activity is required for cancer protein-interaction phenotypes unknown