Affinage

TOX2

TOX high mobility group box family member 2 · UniProt Q96NM4

Length
488 aa
Mass
51.6 kDa
Annotated
2026-06-10
21 papers in source corpus 9 papers cited in narrative 9 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

TOX2 is an HMG-box transcription factor that directly binds target gene loci to program the differentiation and function of multiple lymphocyte lineages (PMID:31732165, PMID:25352127). In CD4 T cells it is both necessary and sufficient for T follicular helper (Tfh) differentiation, where ectopic expression drives Bcl6 induction and genome-wide ChIP-seq places TOX2 directly on the Bcl6 locus, establishing a Tox2-Bcl6 feed-forward loop and sustaining germinal-center and memory Tfh identity (PMID:31732165, PMID:34623911). In CD8 T cells TOX2 cooperates with TOX and NR4A factors downstream of NFAT to enforce the exhaustion transcriptional program, while in human CAR T cells it instead binds central-memory gene promoters to promote TCM differentiation (PMID:31152140, PMID:37467321). TOX2 also acts upstream in innate lymphocytes, directly upregulating TBX21 (T-BET) transcription to drive human NK cell development and supporting gut ILC3 tissue residency by maintaining Hexokinase-2-dependent glycolysis (PMID:25352127, PMID:38677292). Its activity is gated by Sirt1/TBK1-controlled nuclear-cytosol translocation: nuclear TOX2 forms a complex with TOX, LCOR, and HDAC3 to repress the HAVCR2 (TIM3) promoter (PMID:39080376). In NK/T-cell lymphoma, super-enhancer-driven TOX2 overexpression downstream of RUNX3 promotes oncogenesis through the downstream effector PRL-3 (PMID:37032358).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2014 High

    Established that TOX2 functions in innate lymphocyte development by acting as a direct upstream activator of the master NK transcription factor T-BET, defining its first molecular target.

    Evidence shRNA silencing, overexpression, and T-BET rescue epistasis in CD34+ cord blood NK differentiation

    PMID:25352127

    Open questions at the time
    • Direct binding to the TBX21 locus not demonstrated by ChIP
    • ETS-1 independence shown but other cofactors not mapped
  2. 2019 High

    Defined TOX2 as a driver of CD8 T cell exhaustion acting combinatorially with TOX and NR4A downstream of NFAT, revealing redundancy within the TOX family in dysfunctional T cells.

    Evidence CAR T mouse model, Tox/Tox2 CRISPR double-knockout, ATAC-seq and transcriptional analysis

    PMID:31152140

    Open questions at the time
    • Direct TOX2 target loci in exhaustion not separated from TOX
    • Mechanism of cooperation with NR4A not biochemically resolved
  3. 2019 High

    Showed TOX2 is necessary and sufficient for Tfh differentiation through direct genomic binding to Bcl6, identifying the Tox2-Bcl6 feed-forward loop as its core CD4 T cell circuit.

    Evidence Tox2-/- mouse, ectopic expression, genome-wide ChIP-seq and ATAC-seq, epistasis with Tox

    PMID:31732165

    Open questions at the time
    • Cofactors recruited to TOX2-bound Tfh loci not identified
    • Relationship to TCM/exhaustion programs in CD8 not addressed
  4. 2021 High

    Extended the Tfh role to maintenance, showing TOX2 preserves germinal-center Tfh identity and enables memory Tfh generation rather than just initiating differentiation.

    Evidence Tox2-/- mouse, overexpression in human GC Tfh cells, reimmunization challenge

    PMID:34623911

    Open questions at the time
    • Direct targets enforcing maintenance versus Th1 conversion not mapped
    • Memory Tfh persistence mechanism unresolved
  5. 2023 Medium

    Distinguished TOX2 from TOX functionally, demonstrating TOX2 binds TCM gene promoters to promote central-memory differentiation in human CAR T cells, and linked TET2 loss to elevated TOX2.

    Evidence TOX2 knockdown, ChIP-seq, ATAC-seq, flow cytometry in human CAR T cells

    PMID:37467321

    Open questions at the time
    • Single lab, no in vivo validation
    • Mechanism reconciling memory-promoting versus exhaustion roles unresolved
  6. 2023 Medium

    Identified TOX2 as an oncogenic node in NK/T-cell lymphoma driven by RUNX3 via super-enhancer activation, with PRL-3 as a downstream effector.

    Evidence shRNA knockdown, CRISPR-dCas9 super-enhancer interference, luciferase reporter, ChIP-PCR, xenograft

    PMID:37032358

    Open questions at the time
    • Direct TOX2 binding to the PRL-3 locus not shown
    • Single lab
  7. 2024 High

    Revealed a metabolic function for TOX2 in maintaining gut ILC3 tissue residency through Hexokinase-2-dependent glycolysis, extending its role beyond transcriptional lineage specification.

    Evidence Tox2-/- mouse, single-cell transcriptomics, ectopic Hexokinase-2 rescue, Citrobacter infection and glycolysis assays

    PMID:38677292

    Open questions at the time
    • Direct binding to the Hexokinase-2 locus not demonstrated
    • Upstream hypoxia/IL-17A signaling to TOX2 not mechanistically mapped
  8. 2024 Medium

    Uncovered post-translational control of TOX2 via Sirt1/TBK1-regulated deacetylation and translocation, and a TOX2-TOX-LCOR-HDAC3 repressive complex acting on the TIM3 promoter.

    Evidence Co-IP, subcellular fractionation, luciferase promoter assay, shRNA, HDAC3 inhibition, xenograft in leukemic cells

    PMID:39080376

    Open questions at the time
    • Single Co-IP-based complex without reciprocal structural validation
    • Acetylation sites on TOX2 not mapped
  9. 2025 Medium

    Provided a genome-wide binding map of TOX2 in primary human CD8 T cells, linking its occupancy to exhaustion and memory gene programs.

    Evidence Calling Cards transposon-based TF mapping integrated with multi-omics in primary human CD8 T cells (preprint)

    PMID:bio_10.1101_2025.10.09.681414

    Open questions at the time
    • Single preprint, no functional validation of individual binding events
    • Direct versus indirect targets not resolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • How TOX2 selects between activating (memory, Tfh, T-BET) and repressive (TIM3, exhaustion) transcriptional outputs across lineages, and which cofactors dictate this switch, remains unresolved.
  • No unified cofactor logic explaining context-dependent activator versus repressor roles
  • Structural basis of HMG-box target selection not defined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003677 DNA binding 3 GO:0140110 transcription regulator activity 3
Localization
GO:0005634 nucleus 2 GO:0005829 cytosol 1
Pathway
R-HSA-168256 Immune System 4 R-HSA-74160 Gene expression (Transcription) 3 R-HSA-1643685 Disease 1
Complex memberships
TOX2-TOX-LCOR-HDAC3 repressive complex

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2019 TOX2 cooperates with TOX and NR4A transcription factors downstream of NFAT (in the absence of AP-1) to drive the transcriptional program of CD8+ T cell exhaustion; Tox/Tox2 double-knockout CAR TILs showed increased cytokine expression, decreased inhibitory receptor expression, and increased chromatin accessibility at NFκB/bZIP motif-enriched regions; positive regulatory loops between TOX and NR4A were identified. CAR T cell mouse model, CRISPR double-knockout (Tox DKO), ATAC-seq, transcriptional analysis, genetic epistasis Proceedings of the National Academy of Sciences of the United States of America High 31152140
2019 TOX2 is required for T follicular helper (Tfh) cell differentiation: ectopic expression of Tox2 was sufficient to drive Bcl6 expression and Tfh development; Tox2 ChIP-seq showed direct binding to Bcl6 and other Tfh-associated loci; Tox2 binding was associated with increased chromatin accessibility (ATAC-seq); Tox2-/- mice had defective Tfh differentiation, and combined Tox2/Tox deficiency abolished Tfh differentiation, establishing a Tox2-Bcl6 feed-forward loop. Tox2-/- mouse model, ectopic expression, genome-wide ChIP-seq, ATAC-seq, epistasis with Tox Immunity High 31732165
2014 TOX2 controls human NK cell development by directly upregulating transcription of TBX21 (T-BET), acting upstream of TBX21; TOX2 knockdown hindered early NK cell developmental transitions, and overexpression of T-BET rescued TOX2 knockdown phenotypes; TOX2 acted independently of ETS-1. shRNA gene silencing, overexpression in CD34+ cord blood cells, rescue experiment with T-BET overexpression, in vitro NK cell differentiation assay Blood High 25352127
2021 Tox2 is required for maintenance of germinal center (GC) TFH cells and generation of memory TFH cells; Tox2 overexpression maintained TFH-associated gene expression and inhibited spontaneous conversion of GC TFH cells into TH1-like cells; Tox2-deficient mice showed impaired secondary TFH expansion upon reimmunization. Tox2-/- mouse model, Tox2 overexpression in human GC TFH cells, reimmunization/secondary infection challenge, transcriptional analysis Science advances High 34623911
2023 TOX2 mediates oncogenesis in Natural Killer/T-cell lymphoma (NKTL) downstream of RUNX3, which regulates TOX2 transcription by binding to active elements of its super-enhancer; TOX2 knockdown or CRISPR-dCas9 interference of its super-enhancer impaired cell proliferation, survival, and colony formation in vitro and tumor formation in vivo; PRL-3 (metastasis-associated phosphatase) was identified and validated as a key downstream effector of TOX2. shRNA knockdown, CRISPR-dCas9 SE interference, luciferase reporter assay, ChIP-PCR, in vivo xenograft model Molecular cancer Medium 37032358
2023 In human CAR T cells, TOX2 (in contrast to TOX) promotes central memory T cell (TCM) differentiation: TOX2 knockdown decreased TCM percentage and reduced proliferation; TOX2 bound to promoters of numerous TCM-associated genes; increased TET2 loss led to increased TOX2 expression and chromatin accessibility at TOX2 locus. TOX2 knockdown, ChIP-seq (TOX2 at TCM gene promoters), ATAC-seq, flow cytometry, gene expression analysis in human CAR T cells Science advances Medium 37467321
2024 Tox2 is required for metabolic adaptation and tissue residency of gut ILC3: Tox2 deficiency decreased ILC3 specifically in gut (not central sites) and impaired control of Citrobacter rodentium infection; single-cell transcriptomics revealed decreased Hexokinase-2 expression in Tox2-deficient ILC3; Tox2-/- ILC3 showed decreased glycolytic capacity for protein translation; ectopic Hexokinase-2 expression rescued Tox2-/- ILC3 defects; hypoxia and IL-17A each induced Tox2 expression in ILC3. Tox2-/- mouse model, single-cell transcriptional profiling, ectopic Hexokinase-2 rescue, infection challenge, glycolysis assay Immunity High 38677292
2024 TOX2 nuclear-cytosol translocation is regulated by deacetylation cooperatively mediated by Sirt1 and kinase TBK1; nuclear TOX and TOX2 form a protein complex and repress HAVCR2 (TIM3) promoter activity by recruiting corepressor LCOR and deacetylase HDAC3; radiation damage induced TOX2 nuclear translocation and decreased Sirt1, TIM3, and caspase 1 expression; knockdown of TOX2, TOX, or LCOR, or HDAC3 inhibition induced leukemic cell apoptosis in vitro and reduced tumor growth in vivo. Co-immunoprecipitation (protein complex), subcellular fractionation/localization, luciferase promoter assay, shRNA knockdown, HDAC3 inhibitor, in vivo xenograft model Cell death and differentiation Medium 39080376
2025 Genome-wide binding sites of TOX2 in primary human CD8 T cells were mapped using the Calling Cards transposon-based method; TOX2 binding sites in CD8 T cells were identified and associated with exhaustion and memory gene programs. Calling Cards transposon-based TF mapping (chromatin binding), integration with multi-omic sequencing in primary human CD8 T cells bioRxivpreprint Medium bio_10.1101_2025.10.09.681414

Source papers

Stage 0 corpus · 21 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2019 TOX and TOX2 transcription factors cooperate with NR4A transcription factors to impose CD8+ T cell exhaustion. Proceedings of the National Academy of Sciences of the United States of America 634 31152140
2019 The Transcription Factor Tox2 Drives T Follicular Helper Cell Development via Regulating Chromatin Accessibility. Immunity 136 31732165
1996 Chromosomal organization of TOX2, a complex locus controlling host-selective toxin biosynthesis in Cochliobolus carbonum. The Plant cell 70 8672886
2014 TOX2 regulates human natural killer cell development by controlling T-BET expression. Blood 65 25352127
2021 Tox2 is required for the maintenance of GC TFH cells and the generation of memory TFH cells. Science advances 34 34623911
2022 CD4+ T cells in classical Hodgkin lymphoma express exhaustion associated transcription factors TOX and TOX2: Characterizing CD4+ T cells in Hodgkin lymphoma. Oncoimmunology 31 35111387
2023 Super-enhancer-driven TOX2 mediates oncogenesis in Natural Killer/T Cell Lymphoma. Molecular cancer 27 37032358
2016 Genome-wide Regional Heritability Mapping Identifies a Locus Within the TOX2 Gene Associated With Major Depressive Disorder. Biological psychiatry 24 28153336
2002 An extended physical map of the TOX2 locus of Cochliobolus carbonum required for biosynthesis of HC-toxin. Fungal genetics and biology : FG & B 24 11860263
2023 TOX2 coordinates with TET2 to positively regulate central memory differentiation in human CAR T cells. Science advances 23 37467321
1996 Transposon-like sequences at the TOX2 locus of the plant-pathogenic fungus Cochliobolus carbonum. Gene 20 8918240
2000 Reduced virulence caused by meiotic instability of the TOX2 chromosome of the maize pathogen Cochliobolus carbonum. Molecular plant-microbe interactions : MPMI 18 10656588
2024 Transcription factor Tox2 is required for metabolic adaptation and tissue residency of ILC3 in the gut. Immunity 16 38677292
2023 Geniposide prevents tumor growth by inhibiting colonic interleukin-1β and monocyte chemoattractant protein-1 via down-regulated expression of cyclooxygenase-2 and thymocyte selection-associated high mobility box proteins TOX/TOX2 in azoxymethane/dextran sulfate sodium-treated mice. International immunopharmacology 10 37011499
2022 Two hydroxyflavanones isolated from Scutellaria baicalensis roots prevent colitis-associated colon cancer in C57BL/6 J mice by inhibiting programmed cell death-1, interleukin 10, and thymocyte selection-associated high mobility group box proteins TOX/TOX2. Phytomedicine : international journal of phytotherapy and phytopharmacology 8 35378414
1997 Polymorphic Chromosomes Bearing the Tox2 Locus in Cochliobolus carbonum Behave as Homologs during Meiosis. Applied and environmental microbiology 6 16535561
2024 TOX2 nuclear-cytosol translocation is linked to leukemogenesis of acute T-cell leukemia by repressing TIM3 transcription. Cell death and differentiation 5 39080376
2024 Ulcerative Colitis, LAIR1 and TOX2 Expression, and Colorectal Cancer Deep Learning Image Classification Using Convolutional Neural Networks. Cancers 3 39766129
2023 Acertannin prevents azoxymethane/dextran sulfate sodium-induced colon cancer growth by inhibiting the colonic expression of interleukin-1β, monocyte chemoattractant protein-1, cyclooxygenase-2, and thymocyte selection-associated high mobility group box proteins (TOX)/TOX2 in C57BL/6J mice. European journal of pharmacology 3 36990263
2025 The TOX2 Gene Is Responsible for Conidiation and Full Virulence in Fusarium pseudograminearum. Current issues in molecular biology 0 41020836
1995 [Genetic analysis of Vibrio cholerae chromosomal regions containing the tox-2 mutation, affecting production of cholera toxin]. Molekuliarnaia genetika, mikrobiologiia i virusologiia 0 8604230

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