Affinage

FOXS1

Forkhead box protein S1 · UniProt O43638

Length
330 aa
Mass
35.4 kDa
Annotated
2026-04-28
15 papers in source corpus 15 papers cited in narrative 15 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

FOXS1 is a forkhead box transcription factor that functions as a TGFβ-responsive transcriptional effector regulating fibrosis, EMT, energy homeostasis, and cholesterol metabolism across multiple tissue contexts. In hepatic stellate cells and adipose stem cells, TGFβ induces FOXS1 expression, which drives myofibroblast gene programs (Acta2, Col1a1, Fn1, Il11) while suppressing adipogenic transcription factors, and FOXS1 knockout attenuates hundreds of TGFβ-responsive transcripts (PMID:38280429, PMID:40774386). Beyond its transcriptional roles, FOXS1 engages in direct protein–protein interactions: it binds and stabilizes Gli1 by blocking its ubiquitination to activate Hedgehog signaling (PMID:37890593), interacts with TGFBI to route it for LAMP2A-dependent lysosomal degradation thereby promoting autophagy and tumor suppression in colorectal cancer (PMID:39864590), and directly binds the BSCL2 promoter to suppress cholesterol transporters ABCA1/ABCG1 via the PPARγ/LXRα axis, linking oxLDL signaling to NLRP3 inflammasome activation and aortic valve calcification (PMID:40990096). Foxs1 knockout mice display improved motor coordination and resistance to diet-induced obesity with elevated UCP1, consistent with roles in hypothalamic energy regulation and pericyte/vascular cell survival (PMID:15964817, PMID:18288644).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 2005 High

    Establishing that FOXS1 has in vivo physiological roles beyond a generic transcription factor, Foxs1 knockout mice revealed functions in motor coordination and energy homeostasis, with expression mapped to hypothalamic neurons, cerebellar neurons, DRG, and CNS pericytes.

    Evidence Foxs1 knock-in/knockout mouse with β-gal reporter; rotarod, body weight, and UCP1 mRNA assays

    PMID:15964817

    Open questions at the time
    • Downstream transcriptional targets mediating motor and metabolic phenotypes not identified
    • Mechanism linking pericyte expression to energy homeostasis unknown
    • No conditional knockout to dissect tissue-specific contributions
  2. 2007 Medium

    FOXS1 was placed in the developmental context of sensory neurogenesis, marking early sensory neuron precursors across neural crest and placode lineages in a pattern mutually exclusive with Sox10 in multipotent progenitors.

    Evidence Immunofluorescence, in situ hybridization, and lineage tracing in mouse embryos

    PMID:17309606

    Open questions at the time
    • Functional requirement for FOXS1 in sensory neuron specification not tested by loss-of-function
    • Relationship between FOXS1 expression and downstream sensory fate genes unknown
  3. 2008 Medium

    A vascular survival function was identified: Foxs1 knockout causes apoptosis of periendothelial cells in fetal testis through derepression of FoxO3a/FoxO4, elevating FasL-mediated cell death.

    Evidence Knockout mouse with EM, caspase-3 immunostaining, and FoxO transcriptional activity assays

    PMID:18288644

    Open questions at the time
    • Direct DNA-binding targets mediating FoxO suppression not mapped
    • Whether vascular phenotype extends beyond fetal testis not tested
    • Single lab observation
  4. 2017 Medium

    FOXS1 was linked to interferon signaling regulation in endometrial epithelial cells, where it modulates expression of IRF3, IRF9, STAT1, and STAT2 downstream of interferon-tau stimulation.

    Evidence siRNA knockdown with RT-PCR validation in IFNT-treated primary bovine endometrial epithelial cells

    PMID:28199372

    Open questions at the time
    • Whether FOXS1 directly binds promoters of interferon pathway genes not tested
    • Bovine-specific context; relevance to human interferon signaling unconfirmed
  5. 2018 Medium

    FOXS1 was identified as a tumor suppressor in gastric cancer that negatively regulates the Wnt/β-catenin pathway, decreasing β-catenin, c-Myc, and cyclin-D1 and suppressing EMT.

    Evidence Bidirectional overexpression/knockdown in gastric cancer cell lines with Western blot and xenograft validation

    PMID:30500980

    Open questions at the time
    • Mechanism of Wnt pathway suppression (direct binding vs. indirect) not resolved
    • Contrasts with later findings showing FOXS1 as pro-EMT in other cancer types
  6. 2019 Medium

    Upstream regulation of FOXS1 was mapped: GLI1 directly binds the FOXS1 promoter to repress it, and miR-125a-5p post-transcriptionally represses FOXS1 via its 3′UTR; in this gastric cancer context FOXS1 promoted rather than suppressed proliferation and EMT.

    Evidence ChIP for GLI1 at FOXS1 promoter, 3′UTR luciferase assay, siRNA/overexpression in gastric cancer lines

    PMID:30918291

    Open questions at the time
    • Context-dependent tumor-suppressive vs. oncogenic roles of FOXS1 not mechanistically reconciled
    • GLI1 repression of FOXS1 contrasts with later finding of FOXS1 stabilizing GLI1 protein
  7. 2021 Medium

    A paracrine mechanism was identified whereby glioma-associated mesenchymal stem cells secrete IL-6 to induce FOXS1 in glioma cells, driving EMT and temozolomide resistance.

    Evidence Conditioned media, gene microarray, lentiviral overexpression/knockdown, xenograft model

    PMID:34256854

    Open questions at the time
    • Direct transcriptional targets of FOXS1 in glioma not mapped
    • Whether IL-6–FOXS1 axis operates in other tumor types unknown
  8. 2022 Medium

    A direct transcriptional target in colorectal cancer was identified: FOXS1 upregulates CXCL8, which mediates FOXS1-driven EMT and angiogenesis.

    Evidence CXCL8 knockdown epistasis reversing FOXS1 phenotype; tube formation, CAM, orthotopic mouse model, clinical IHC

    PMID:35898871

    Open questions at the time
    • Whether FOXS1 directly binds the CXCL8 promoter not confirmed by ChIP
    • Contribution of other FOXS1 targets to angiogenesis not excluded
  9. 2023 Medium

    A non-transcriptional mechanism was uncovered: FOXS1 physically binds Gli1 protein and blocks its ubiquitination, stabilizing Gli1 to activate Hedgehog signaling in prostate cancer.

    Evidence Co-IP, ubiquitination assay, Gli1 overexpression rescue of FOXS1 knockdown, nude mouse model

    PMID:37890593

    Open questions at the time
    • The E3 ligase whose activity is blocked by FOXS1 binding is not identified
    • Structural basis of FOXS1–Gli1 interaction unknown
    • Single lab; reciprocal IP not described in detail
  10. 2024 High

    FOXS1 was established as a central TGFβ-responsive transcriptional effector: CRISPR knockout in hepatic stellate cells attenuated >400 TGFβ-responsive transcripts, and FOXS1 controls pathways of TGFβ responsiveness, translation, and proliferation. Concurrently, FOXS1 was shown to promote renal fibrosis via Wnt/β-catenin and EMT, and to interact with HILPDA to activate FAK/PI3K/AKT in prostate cancer.

    Evidence CRISPR KO in LX2 cells with RNA-seq and PamGene kinase profiling; bidirectional modulation in HK-2 renal cells and UUO mouse model; Co-IP for HILPDA in prostate cancer lines

    PMID:38280429 PMID:38780613 PMID:39709913

    Open questions at the time
    • Direct FOXS1 chromatin-binding sites genome-wide in stellate cells not mapped by ChIP-seq
    • Whether FOXS1–HILPDA interaction is direct or mediated through a complex is unclear
    • Mechanism by which FOXS1 activates Wnt/β-catenin in renal fibrosis not resolved
  11. 2025 High

    Multiple direct mechanisms of FOXS1 were resolved: (1) FOXS1 interacts with TGFBI and routes it for LAMP2A-dependent lysosomal degradation, promoting autophagy and suppressing CRC growth via AKT/FOXO3a; (2) FOXS1 directly binds the BSCL2 promoter to suppress cholesterol efflux via PPARγ/LXRα, activating NLRP3 inflammasome and aortic valve calcification; (3) FOXS1 potentiates TGFβ1-driven myofibroblast programs while suppressing adipogenesis in adipose stem cells.

    Evidence Co-IP and LAMP2A interaction assays, LC3 autophagy flux, in vivo CRC model; ChIP-seq for BSCL2, cholesterol transport assay, Apoe−/−Foxs1−/− mouse; TGFβ1 gain/loss-of-function in primary human ASCs

    PMID:39864590 PMID:40774386 PMID:40990096

    Open questions at the time
    • Whether the TGFBI-degradation and Gli1-stabilization functions of FOXS1 share a common protein-interaction domain is unknown
    • Genome-wide direct transcriptional targets of FOXS1 across tissues remain incompletely catalogued
    • Structural basis for FOXS1 binding to BSCL2 promoter versus other forkhead sites not resolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • The context-dependent switching of FOXS1 between tumor-suppressive (gastric cancer, CRC) and oncogenic (glioma, prostate cancer) functions remains mechanistically unexplained, and no comprehensive ChIP-seq map of direct FOXS1 binding sites across tissues exists.
  • No crystal structure or domain-resolution interaction mapping for FOXS1
  • Tissue-specific cofactors that determine pro- vs. anti-tumorigenic activity not identified
  • Post-translational regulation of FOXS1 protein stability largely unexplored

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140110 transcription regulator activity 6 GO:0098772 molecular function regulator activity 3 GO:0003677 DNA binding 2
Localization
GO:0005634 nucleus 4
Pathway
R-HSA-1643685 Disease 6 R-HSA-162582 Signal Transduction 5 R-HSA-74160 Gene expression (Transcription) 3 GO:0005634 nucleus 2 R-HSA-9612973 Autophagy 1
Partners
BSCL2FOXO3AGLI1HILPDALAMP2ATGFBI

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2005 Foxs1 knockout mice (Foxs1beta-gal/beta-gal) show improved rotarod performance and reduced body weight gain on high-fat diet, with increased UCP1 mRNA; Foxs1 is expressed in dorsomedial hypothalamic neurons, cerebellar internal granule layer, dorsal root ganglia, CNS blood vessel pericytes and smooth muscle cells, establishing a role in motor function and energy homeostasis. Knock-in/knockout mouse model (beta-galactosidase reporter), rotarod behavioral assay, body weight measurement, UCP1 mRNA quantification Molecular and cellular biology High 15964817
2007 Foxs1 expression marks early sensory neuron precursors across both placode- and neural crest-derived lineages; Foxs1 expression is mutually exclusive with Sox10 in multipotent neural crest cells, defining a sequential emergence of sensory neuron precursors during DRG development. Immunofluorescence, in situ hybridization, lineage tracing in mouse embryos Differentiation; research in biological diversity Medium 17309606
2008 Fkhl18 (mouse ortholog of FOXS1/FoxS subfamily) is expressed in periendothelial cells of fetal testis; its knockout causes apoptosis of periendothelial cells (via caspase-3 activation) and vascular gaps; Fkhl18 suppresses FoxO3a and FoxO4 transcriptional activity, and its absence elevates FoxO-driven Fas ligand expression. Knockout mouse generation, electron microscopy, caspase-3 immunostaining, transcriptional activity assays Molecular reproduction and development Medium 18288644
2017 FOXS1 is upregulated by IFNT2 and IFNTc1 in bovine endometrial epithelial cells; FOXS1 knockdown in IFNT-treated cells down-regulates IRF3 and IRF9 and up-regulates STAT1, STAT2, and IRF8, placing FOXS1 as a regulator of interferon signaling genes in endometrium. RNA-seq, siRNA knockdown, RT-PCR in primary bovine endometrial epithelial cells PloS one Medium 28199372
2018 FOXS1 overexpression in gastric cancer cell lines suppresses cell proliferation, metastasis, and EMT, and decreases β-catenin, c-Myc, and cyclin-D1 expression, while FOXS1 knockdown has opposite effects, placing FOXS1 as a negative regulator of the Wnt/β-catenin pathway. Overexpression and knockdown in gastric cancer cell lines, Western blot for pathway markers, xenograft mouse model Journal of cellular biochemistry Medium 30500980
2019 GLI1 directly binds the FOXS1 promoter and decreases FOXS1 expression; miR-125a-5p represses FOXS1 at the translational level by binding the 3'UTR of FOXS1; NFKB1 indirectly inhibits FOXS1 via its promoter motif; FOXS1 promotes gastric cancer cell proliferation and EMT. Promoter-reporter assay, ChIP, 3'UTR luciferase assay, siRNA/overexpression, GSEA Scientific reports Medium 30918291
2021 CD90low glioma-associated MSCs secrete IL-6 to increase FOXS1 expression in glioma cells; elevated FOXS1 activates EMT and promotes temozolomide resistance; FOXS1 knockdown reverses these effects both in vitro and in vivo. Conditioned media experiments, gene microarray, lentiviral overexpression/knockdown, flow cytometry, xenograft mouse model Stem cell research & therapy Medium 34256854
2022 FOXS1 transcriptionally upregulates CXCL8 in colorectal cancer cells; CXCL8 knockdown blocks FOXS1-induced EMT and angiogenesis, and FOXS1 expression correlates with CXCL8 and CD31 levels in clinical samples. siRNA knockdown, RT-PCR, Western blot, tube formation assay, CAM assay, orthotopic mouse model, IHC in clinical samples Frontiers in oncology Medium 35898871
2023 FOXS1 physically binds Gli1 and inhibits Gli1 ubiquitination, thereby stabilizing Gli1 and activating Hedgehog signaling to promote prostate cancer cell growth and metastasis; Gli1 overexpression or Hh pathway activation reverses the effects of FOXS1 silencing. Co-IP, ubiquitination assay, siRNA knockdown, Gli1 overexpression, nude mouse tumorigenesis model Biochemical pharmacology Medium 37890593
2024 TGFβ induces FOXS1 expression in hepatic stellate cells (HSCs); FOXS1 CRISPR KO in LX2 cells attenuates over 400 TGFβ-responsive transcripts, and controls pathways mediating TGFβ responsiveness, protein translation, and proliferation as determined by RNA-seq and kinase activity profiling. CRISPR KO in LX2 HSCs, RNA-seq, PamGene kinase activity assay, RT-qPCR, murine fibrosis model The Journal of biological chemistry High 38280429
2024 FOXS1 directly interacts with HILPDA in prostate cancer cells; this interaction activates the FAK/PI3K/AKT pathway and promotes EMT; modulating FOXS1 expression bidirectionally alters cell growth, migration, and invasion. Co-IP, Western blot, CCK-8, wound-healing, Transwell assays, bioinformatics, IHC in clinical samples FASEB journal Medium 38780613
2024 ADSC-derived extracellular vesicles reduce FOXS1 expression in TGF-β1-treated renal tubular cells, attenuating Wnt/β-catenin pathway activation and EMT; FOXS1 overexpression promotes and knockdown reduces renal fibrosis. RNA-seq of HK-2 cells, RT-qPCR, Western blot, siRNA/overexpression, UUO mouse model in vivo International immunopharmacology Medium 39709913
2025 TGFβ1 induces FOXS1 expression in human adipose stem cells; FOXS1 potentiates TGFβ1-dependent upregulation of myofibroblast genes (Acta2, Col1a1, Fn1, Il11) and suppresses adipogenic genes (Pparg, Stat5a, Fabp4, Adipoq); loss of endogenous FOXS1 improves adipogenic permissiveness even under TGFβ1 stimulation. TGFβ1 stimulation of primary human ASCs and 10T1/2 fibroblasts, FOXS1 overexpression and loss-of-function, qPCR/Western blot for downstream genes The Journal of biological chemistry Medium 40774386
2025 FOXS1 directly interacts with TGFBI protein and promotes its degradation via the autophagy-lysosome pathway (not ubiquitin-proteasome); FOXS1 facilitates the interaction between TGFBI and LAMP2A for lysosomal translocation; FOXS1 also regulates AKT phosphorylation and FOXO3a nuclear translocation to promote autophagy-related gene transcription; restoration of TGFBI reverses FOXS1-mediated growth suppression in CRC cells. Co-IP, GFP-LC3 puncta, Ad-mCherry-GFP-LC3B autophagy flux assay, protein stability analysis, immunofluorescence, Western blot, RNA-seq, in vivo subcutaneous tumor model Journal of advanced research High 39864590
2025 In aortic valve interstitial cells, oxLDL induces FOXS1 which directly binds the BSCL2 promoter (ChIP-seq); FOXS1-driven BSCL2 expression inhibits ABCA1 and ABCG1 via the PPARγ/LXRα axis, causing cholesterol transport dysfunction and NLRP3 inflammasome activation, thereby promoting osteogenic differentiation and aortic valve calcification; Foxs1 deletion in Apoe−/− mice reduces aortic valve calcification. ChIP-seq, RNA-seq, Bodipy-cholesterol transport assay, siRNA/adenoviral modulation of FOXS1 in VICs, Apoe−/−Foxs1−/− mouse model on HFD Cardiovascular research High 40990096

Source papers

Stage 0 corpus · 15 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2005 Lack of the central nervous system- and neural crest-expressed forkhead gene Foxs1 affects motor function and body weight. Molecular and cellular biology 48 15964817
2007 Emergence of the sensory nervous system as defined by Foxs1 expression. Differentiation; research in biological diversity 42 17309606
2021 CD90low glioma-associated mesenchymal stromal/stem cells promote temozolomide resistance by activating FOXS1-mediated epithelial-mesenchymal transition in glioma cells. Stem cell research & therapy 31 34256854
2019 FOXS1 is regulated by GLI1 and miR-125a-5p and promotes cell proliferation and EMT in gastric cancer. Scientific reports 25 30918291
2008 Importance of forkhead transcription factor Fkhl18 for development of testicular vasculature. Molecular reproduction and development 21 18288644
2018 Overexpression of FOXS1 in gastric cancer cell lines inhibits proliferation, metastasis, and epithelial-mesenchymal transition of tumor through downregulating wnt/β-catenin pathway. Journal of cellular biochemistry 14 30500980
2017 Endometrial factors similarly induced by IFNT2 and IFNTc1 through transcription factor FOXS1. PloS one 14 28199372
2024 FOXS1 is increased in liver fibrosis and regulates TGFβ responsiveness and proliferation pathways in human hepatic stellate cells. The Journal of biological chemistry 13 38280429
2022 FOXS1 Promotes Tumor Progression by Upregulating CXCL8 in Colorectal Cancer. Frontiers in oncology 13 35898871
2023 FOXS1 promotes prostate cancer progression through the Hedgehog/Gli1 pathway. Biochemical pharmacology 10 37890593
2024 FOXS1 acts as an oncogene and induces EMT through FAK/PI3K/AKT pathway by upregulating HILPDA in prostate cancer. FASEB journal : official publication of the Federation of American Societies for Experimental Biology 6 38780613
2024 Adipose mesenchymal stem cell-derived extracellular vesicles alleviate renal fibrosis by reducing epithelial-mesenchymal transition via the FOXS1/Wnt/β-catenin signaling pathway. International immunopharmacology 5 39709913
2025 Oxidized LDL-induced FOXS1 mediates cholesterol transport dysfunction and inflammasome activation to drive aortic valve calcification. Cardiovascular research 1 40990096
2025 FOXS1, frequently inactivated by promoter methylation, inhibited colorectal cancer cell growth by promoting TGFBI degradation through autophagy-lysosome pathway. Journal of advanced research 0 39864590
2025 TGF-β1-dependent expression of FOXS1 attenuates adipogenic potential and enhances a myofibroblast cellular phenotype. The Journal of biological chemistry 0 40774386