Affinage

TAF2

Transcription initiation factor TFIID subunit 2 · UniProt Q6P1X5

Length
1199 aa
Mass
137.0 kDa
Annotated
2026-06-10
15 papers in source corpus 13 papers cited in narrative 13 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

TAF2 is a subunit of the general transcription factor TFIID that confers core-promoter selectivity by recognizing the initiator element at the transcription start site, where it acts together with TBP to extend TFIID's contacts across the core promoter (PMID:8178153, PMID:9418870). It is positioned within TFIID adjacent to TAF1 and TBP and stabilizes TFIID binding to initiator-containing promoters (PMID:9418870, PMID:19278651). TAF2 reaches TFIID through an ordered assembly route: it first forms a cytoplasmic heterotrimer with TAF8 and TAF10, binding multiple motifs in the TAF8 C-terminal proline-rich region, and this preassembled submodule is imported and incorporated into nuclear core-TFIID—an interaction so central that loss of the TAF8 region engaging TAF2 abolishes embryonic stem cell survival (PMID:25586196, PMID:34634302). Although associated only sub-stoichiometrically with TFIID, TAF2 governs TBP/TFIID occupancy and transcription at a restricted subset of genes: it selectively drives cyclin B1 and cyclin A transcription to permit G2/M progression, and it controls ribosomal protein genes such as RPL30 and RPL39, so that its loss impairs ribosome assembly and global translation (PMID:10409744, PMID:38773077). Beyond its TFIID role, a conserved intrinsically disordered region partitions TAF2 into nuclear speckle condensates where it engages the splicing factor SRRM2 and modulates alternative splicing (PMID:40287942). In yeast, the Taf2 C-terminal tail recruits Taf14 into TFIID and allosterically relieves Taf14 autoinhibition to license its DNA/nucleosome binding (PMID:27587401, PMID:35676274). Hepatocyte-specific loss of Taf2 in mice triggers cell death, compensatory proliferation, and an inflammatory/fibrotic state, with TAF2 binding promoters of tumor-promoting genes (PMID:40392063).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 1994 High

    Established that the TAF2 ortholog is the TFIID component responsible for core-promoter recognition beyond TBP, answering how TFIID engages the initiator region.

    Evidence Biochemical co-purification and direct DNA/protein binding with purified recombinant Drosophila TAFII150

    PMID:8178153

    Open questions at the time
    • Did not define the human ortholog's behavior
    • Initiator binding determinants within TAF2 not mapped at residue level
  2. 1998 High

    Showed the human protein mediates TFIID-dependent initiator activity and stabilizes TFIID on Inr promoters, but is insufficient alone—additional cofactors and TFIIA are required for promoter-selective synergism.

    Evidence In vitro complementation, direct binding assays, and reconstitution with purified GTFs and cofactor fractions

    PMID:9418870 PMID:9774672

    Open questions at the time
    • Molecular identities/mechanism of TIC-1/2/3 cofactors unresolved
    • Promoter scope of Inr selectivity not defined genome-wide
  3. 1999 High

    Linked TAF2 function to cell cycle control by identifying selective transcriptional targets, demonstrating that loss causes G2/M arrest via reduced cyclin B1/A expression.

    Evidence Transient functional knockout, in vitro transcription, and cyclin B1 promoter element mapping

    PMID:10409744

    Open questions at the time
    • Mechanism of target selectivity not explained
    • Direct vs indirect promoter effects not fully separated
  4. 2009 High

    Placed Taf2 spatially within TFIID near Taf1 and TBP and showed taf1-dependence of Taf2 promoter occupancy, providing structural and genome-wide context for its function.

    Evidence Cryo-EM/electron tomography with immunolabeling and ChIP-chip in yeast

    PMID:19278651 PMID:20026583

    Open questions at the time
    • High-resolution atomic placement of Taf2 not achieved
    • Conformational differences across promoter classes only inferred
  5. 2015 High

    Defined the assembly pathway by showing TAF2 enters TFIID via a cytoplasmic TAF8-nucleated TAF2-TAF8-TAF10 submodule, establishing stepwise holo-TFIID formation through nuclear import.

    Evidence Native mass spectrometry, X-ray crystallography of TAF8-TAF10 histone folds, and Co-IP

    PMID:25586196

    Open questions at the time
    • Nuclear import machinery for the submodule not identified
    • Kinetics of submodule integration into core-TFIID unknown
  6. 2021 High

    Mapped four discrete TAF8 proline-rich regions each required for TAF2 binding and demonstrated this interface is essential for cell viability.

    Evidence In vitro assembly assays, Co-IP, and CRISPR/Cas9 deletion with ESC survival readout

    PMID:34634302

    Open questions at the time
    • Whether viability loss reflects TFIID disassembly specifically not isolated
    • Structure of the TAF2-TAF8 interface unresolved
  7. 2016 High

    Identified the yeast Taf2 C-terminus as the recruiter of Taf14 into TFIID using a separation-of-function allele, distinguishing TFIID incorporation from Taf14 recruitment.

    Evidence Systematic mutagenesis, ts allele screen, in vitro/in vivo Co-IP, and suppression genetics

    PMID:27587401

    Open questions at the time
    • Conservation of this recruitment in human TAF2 not established
    • Functional consequence of Taf14 loss from TFIID not fully detailed here
  8. 2022 High

    Provided the mechanism for Taf2-Taf14 functional coupling: Taf2 binding to Taf14 YEATS/ET domains relieves an autoinhibitory linker, licensing Taf14 DNA/nucleosome binding required for transcription.

    Evidence X-ray crystallography, in vitro binding, mutagenesis, and in vivo genetics in yeast

    PMID:35676274

    Open questions at the time
    • Human relevance of the allosteric mechanism unknown
    • How this gates promoter-specific transcription not resolved
  9. 2024 High

    Demonstrated that despite sub-stoichiometric TFIID association, TAF2 selectively controls a small gene subset including ribosomal protein genes, linking TAF2 loss to impaired ribosome assembly and translation.

    Evidence Inducible TAF2 degradation, genome-wide ChIP-seq, ribosome assembly and translation assays

    PMID:38773077

    Open questions at the time
    • Basis for promoter selectivity at the sequence level unresolved
    • Single-lab observation
  10. 2025 High

    Revealed a TFIID-independent role: a conserved IDR drives TAF2 into nuclear speckles where it binds SRRM2 and influences alternative splicing, expanding TAF2 function beyond transcription initiation.

    Evidence Live-cell imaging, proximity mass spectrometry, ChIP-seq, splicing analysis, and IDR deletion mutant

    PMID:40287942

    Open questions at the time
    • Direct vs scaffolding role in splicing not distinguished
    • Relationship between condensate partitioning and TFIID occupancy unclear
  11. 2025 Medium

    Established an in vivo physiological/pathological role by showing hepatocyte Taf2 loss causes cell death, fibrosis, and inflammation, with TAF2 binding tumor-promoting gene promoters.

    Evidence Hepatocyte-specific conditional knockout mouse, ChIP, and knockdown/overexpression in HCC cells

    PMID:40392063

    Open questions at the time
    • Mechanistic detail limited to abstract-level promoter binding
    • Causal link between specific targets and phenotype not dissected

Open questions

Synthesis pass · forward-looking unresolved questions
  • How TAF2 achieves selectivity for its restricted target gene set and how its TFIID-bound and condensate/splicing functions are mechanistically coordinated remain unresolved.
  • No sequence/structural determinant for promoter selectivity defined
  • Interplay between IDR-driven condensation and core-promoter occupancy unknown
  • Human conservation of yeast Taf2-Taf14 allostery untested

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003677 DNA binding 2 GO:0060090 molecular adaptor activity 2 GO:0140110 transcription regulator activity 2
Localization
GO:0005634 nucleus 1 GO:0005654 nucleoplasm 1 GO:0005829 cytosol 1
Pathway
R-HSA-74160 Gene expression (Transcription) 3 R-HSA-1640170 Cell Cycle 1 R-HSA-8953854 Metabolism of RNA 1
Partners
SRRM2TAF1TAF10TAF14TAF8TBP
Complex memberships
TFIIDcytoplasmic TAF2-TAF8-TAF10 submodule

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1994 Drosophila TAFII150 (TAF2 ortholog) directly binds TBP and dTAFII250, and binds specifically to DNA sequences overlapping the transcription start site, demonstrating that TAFII150 together with TBP are responsible for TFIID interactions with an extended region of the core promoter including the initiator. Biochemical co-purification, direct DNA binding studies with purified recombinant protein, in vivo association assays Science High 8178153
1998 Human TAFII150/CIF150 (TAF2) mediates TFIID-dependent initiator (Inr) activity; it directly interacts with hTAFII135, stabilizes TFIID binding to core promoters containing Inr elements, and can complement TFIID fractions lacking Inr activity. In vitro complementation assay, in vitro binding assays (direct protein-protein interaction), biochemical fractionation Molecular and cellular biology High 9418870
1998 Human TAFII150-containing TFIID complex is not sufficient alone for initiator-directed transcription; novel cofactors TIC-1, TIC-2, and TIC-3 and TFIIA are additionally required for TAFII-mediated core promoter-selective transcription synergism. In vitro transcription reconstitution with purified GTFs, RNA polymerase II, and partially purified cofactor fractions Molecular and cellular biology High 9774672
1999 Functional knockout of CIF150/hTAFII150 (TAF2) causes G2/M cell cycle arrest and selectively reduces transcription of cyclin B1 and cyclin A; a CIF150-responsive cis-element was identified in the cyclin B1 core promoter. Transient functional knockout, gel filtration, PCR display analysis, cotransfection assays, in vitro transcription assays Molecular and cellular biology High 10409744
2009 Yeast Taf2p is positioned within the TFIID complex in the vicinity of Taf1p and TBP, as determined by cryo-EM structural mapping using a Taf2p-depleted TFIID preparation and immunolabeling with a subunit-specific antibody. Electron tomography, cryo-electron microscopy, immunolabeling with subunit-specific antibody, comparison of Taf2p-containing vs Taf2p-depleted TFIID Structure High 19278651
2009 In yeast, a taf1 mutation specifically reduces Taf2 occupancy at promoters genome-wide, and sequential ChIP suggests different TFIID conformations exist at different promoters (RPGs vs non-RPGs), with SAGA and TFIID co-localizing on RPG promoters. ChIP-chip genome-wide localization, conventional and sequential ChIP Nucleic acids research Medium 20026583
2015 TAF2 assembles with TAF8 and TAF10 into a heterotrimeric cytoplasmic subcomplex; TAF8 nucleates the complex; TAF2 binds multiple motifs within the TAF8 C-terminal region; this cytoplasmic assembly dictates TAF2 incorporation into nuclear core-TFIID, providing evidence for stepwise holo-TFIID assembly via nuclear import of preformed cytoplasmic submodules. Native mass spectrometry, X-ray crystallography of TAF8-TAF10 histone fold domains, co-immunoprecipitation, biochemical fractionation Nature communications High 25586196
2016 The C-terminal region of yeast Taf2 directly interacts with Taf14 and mediates stable incorporation of Taf14 into the TFIID complex; a Taf2-ΔC separation-of-function variant incorporates into TFIID but lacks Taf14, demonstrating the Taf2 C-terminus specifically mediates Taf14 recruitment. Site-directed mutagenesis (systematic), temperature-sensitive allele screen, in vitro and in vivo co-immunoprecipitation, overexpression suppression genetics The Journal of biological chemistry High 27587401
2021 Four distinct regions in the TAF8 C-terminal proline-rich domain are each individually required for interaction with TAF2 in TFIID lobe C; CRISPR/Cas9 deletion of the TAF8 proline-rich domain that interacts with TAF2 abolishes mouse embryonic stem cell survival. In vitro assembly assays, co-immunoprecipitation, CRISPR/Cas9 gene editing with cell viability readout The Journal of biological chemistry High 34634302
2022 The YEATS and ET domains of yeast Taf14 bind the C-terminal tail of Taf2; Taf2 binding promotes a conformational rearrangement in Taf14 that releases an autoinhibited linker region, enabling Taf14 to bind DNA and nucleosomes; in vivo, Taf14 association with both Taf2 and DNA is essential for transcriptional regulation. X-ray crystallography/structural determination, in vitro binding assays, mutagenesis, in vivo genetic assays Nature communications High 35676274
2024 TAF2 is sub-stoichiometrically associated with TFIID and regulates TBP/TFIID binding and transcription of only a small subset of protein-coding genes, including ribosomal protein genes RPL30 and RPL39; TAF2 depletion reduces ribosome assembly and global protein translation. Co-immunoprecipitation, inducible TAF2 degradation system, genome-wide ChIP-seq, ribosome assembly assay, protein translation assay Cell death discovery High 38773077
2025 TAF2 contains a conserved intrinsically disordered region (IDR) that drives TAF2 condensation into nuclear speckles independently of other TFIID subunits; the TAF2 IDR directly interacts with the RNA splicing factor SRRM2 in nuclear speckles; IDR deletion does not majorly affect global gene expression but alters alternative splicing events and increases TAF2 promoter association. Live-cell imaging, quantitative proximity mass spectrometry, genome-wide ChIP-seq, alternative splicing analysis, IDR deletion mutant Cell reports High 40287942
2025 Hepatocyte-specific conditional knockout of Taf2 causes hepatocyte death and compensatory proliferation leading to an inflammatory/fibrotic environment; TAF2 binds promoters of tumor-promoting genes and non-coding RNAs to regulate their transcription. Hepatocyte-specific conditional knockout mouse, ChIP (promoter binding), TAF2 knockdown and overexpression in human HCC cells Hepatology Medium 40392063

Source papers

Stage 0 corpus · 15 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1994 Drosophila TAFII150: similarity to yeast gene TSM-1 and specific binding to core promoter DNA. Science (New York, N.Y.) 199 8178153
2015 Cytoplasmic TAF2-TAF8-TAF10 complex provides evidence for nuclear holo-TFIID assembly from preformed submodules. Nature communications 80 25586196
1998 Novel cofactors and TFIIA mediate functional core promoter selectivity by the human TAFII150-containing TFIID complex. Molecular and cellular biology 62 9774672
1998 CIF150, a human cofactor for transcription factor IID-dependent initiator function. Molecular and cellular biology 58 9418870
2009 Mapping the initiator binding Taf2 subunit in the structure of hydrated yeast TFIID. Structure (London, England : 1993) 37 19278651
2013 Microcephaly thin corpus callosum intellectual disability syndrome caused by mutated TAF2. Pediatric neurology 31 24084144
1999 Human transcription factor hTAF(II)150 (CIF150) is involved in transcriptional regulation of cell cycle progression. Molecular and cellular biology 29 10409744
2016 The C Terminus of the RNA Polymerase II Transcription Factor IID (TFIID) Subunit Taf2 Mediates Stable Association of Subunit Taf14 into the Yeast TFIID Complex. The Journal of biological chemistry 15 27587401
2009 Genome-wide localization analysis of a complete set of Tafs reveals a specific effect of the taf1 mutation on Taf2 occupancy and provides indirect evidence for different TFIID conformations at different promoters. Nucleic acids research 12 20026583
2022 Taf2 mediates DNA binding of Taf14. Nature communications 9 35676274
2021 TAF8 regions important for TFIID lobe B assembly or for TAF2 interactions are required for embryonic stem cell survival. The Journal of biological chemistry 6 34634302
2024 TAF2, within the TFIID complex, regulates the expression of a subset of protein-coding genes. Cell death discovery 5 38773077
2021 Phenotype associated with TAF2 biallelic mutations: A clinical description of four individuals and review of the literature. European journal of medical genetics 5 34474177
2025 TAF2 condensation in nuclear speckles links basal transcription factor TFIID to RNA splicing factors. Cell reports 3 40287942
2025 TATA-box binding protein-associated factor 2 (TAF2) in hepatocyte survival and tumorigenesis. Hepatology (Baltimore, Md.) 1 40392063

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