{"gene":"GTF2F1","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":1992,"finding":"RAP74 (GTF2F1) is the large subunit of the TFIIF (RAP30/74) complex; recombinant RAP74 produced in E. coli, together with RAP30, reconstitutes accurate transcription initiation by RNA polymerase II in vitro, and both RAP30 and RAP74 are physical components of the preinitiation complex.","method":"In vitro transcription reconstitution with recombinant proteins; biochemical fractionation","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution of accurate transcription with recombinant subunits, replicated in subsequent studies","pmids":["1734284"],"is_preprint":false},{"year":1994,"finding":"Both RAP30 and RAP74 subunits of TFIIF contribute to formation of stable preinitiation intermediates containing RNA polymerase II, synthesis of the first phosphodiester bonds during initiation, and stimulation of the rate of RNA chain elongation.","method":"Highly purified in vitro transcription system; template competition experiments; kinetic elongation assays with reconstituted TFIIF","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with multiple orthogonal functional assays (initiation, elongation, preinitiation complex formation)","pmids":["7929273"],"is_preprint":false},{"year":1995,"finding":"TAFII250 specifically interacts with RAP74 in vitro, and this interaction is critical for cell viability as shown by in vivo complementation of a temperature-sensitive TAFII250 cell line; the interaction domain on RAP74 was mapped by in vitro binding assays.","method":"In vitro binding assays (pulldown/co-IP); in vivo complementation of ts-TAFII250 cell line","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal binding assays plus in vivo functional complementation, replicated with the kinase study","pmids":["7590250"],"is_preprint":false},{"year":1995,"finding":"RAP74's central charged cluster domain binds the transcriptional activation domain of serum response factor (SRF); deletion of this domain impairs SRF-activated but not basal or SP1-activated transcription in vitro.","method":"Yeast two-hybrid interaction assay; in vitro transcription with RAP74 deletion mutants","journal":"Nature","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid plus functional in vitro transcription assay, single lab","pmids":["7854423"],"is_preprint":false},{"year":1995,"finding":"Deletion mutagenesis of RAP74 mapped its RAP30-binding domain to amino acids 1–172, identified a partially masked RNA polymerase II binding domain at the C-terminal region (aa 363–444), and showed that aa 1–205 are minimally sufficient to stimulate accurate transcription in vitro.","method":"Deletion mutagenesis; in vitro binding and transcription assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — systematic deletion mutagenesis combined with multiple in vitro functional assays in the same study","pmids":["7592953"],"is_preprint":false},{"year":1996,"finding":"TAFII250 is a protein serine kinase that selectively phosphorylates RAP74 but not other basal transcription factors; TAFII250 contains two distinct kinase domains, both required for efficient transphosphorylation of RAP74, and phosphorylation occurs in the context of the complete TFIID complex.","method":"In vitro kinase assay with purified recombinant TAFII250 and RAP74; deletion analysis of TAFII250 kinase domains","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro kinase reconstitution with mutagenesis/deletion analysis, multiple controls","pmids":["8625415"],"is_preprint":false},{"year":1997,"finding":"RAP74 associates with the preinitiation complex in close proximity to promoter DNA both upstream and downstream of a DNA bend centered on the TATA box, and binding of RAP74 induces a conformational change affecting the position of RNA pol II relative to DNA; the N-terminal region containing the RAP30-binding domain is minimally required.","method":"Site-specific protein-DNA photo-crosslinking; deletion analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct crosslinking mapping of RAP74 position in PIC, single lab","pmids":["9207059"],"is_preprint":false},{"year":1997,"finding":"Cell-cycle-dependent phosphorylation of RAP74 by TFIID (S/G2-phase fraction) targets amino acid residues 206–256, and this phosphorylation increases TFIIF transcription activity in vitro.","method":"In vitro kinase assay with synchronized HeLa cell TFIID fractions; RAP74 deletion mutants; in vitro transcription reconstitution","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro kinase and transcription assays, single lab, single study","pmids":["9237686"],"is_preprint":false},{"year":1998,"finding":"FCP1 interacts with the carboxyl-terminal evolutionarily conserved domain of RAP74 (identified by yeast two-hybrid screen); FCP1 is an essential subunit of a RAP74-stimulated phosphatase that processively dephosphorylates the CTD of RNA pol II.","method":"Yeast two-hybrid screen; biochemical phosphatase assay with purified proteins","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — yeast two-hybrid identification plus in vitro phosphatase reconstitution assay, replicated in multiple subsequent studies","pmids":["9765293"],"is_preprint":false},{"year":1998,"finding":"The N-terminal domain of RAP74 (aa 1–172) is sufficient to recruit RNA pol II into the preinitiation complex; the region aa 172–205 (and specifically aa 170–178) is critical for both accurate initiation and elongation; the C-terminal domain does not contribute strongly to single-round initiation or elongation but stimulates multiple-round transcription.","method":"Deletion mutagenesis; in vitro transcription assays (single-round and multiple-round); preinitiation complex assembly assays","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — systematic deletion mutagenesis with multiple in vitro transcription assays distinguishing functional domains","pmids":["9528785"],"is_preprint":false},{"year":1999,"finding":"The region of RAP74 between L155 and M177 is critical for initiation (formation of first phosphodiester bond) but is not required for complex assembly or polymerase II recruitment; negative DNA supercoiling partially compensates for defects in this region, suggesting TFIIF helps untwist DNA for initiation.","method":"Point mutagenesis; in vitro transcription assays; preinitiation complex assembly assays","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — systematic mutagenesis with orthogonal in vitro assays (transcription initiation, complex assembly, supercoiling rescue)","pmids":["10523626"],"is_preprint":false},{"year":1999,"finding":"RAP74 region aa T154–M177 (alpha1 helix region) is critical for isomerization of the preinitiation complex and for elongation stimulation; TFIIF has higher affinity for rapidly elongating RNA pol II than for stalled elongation complexes; TFIIF stimulates elongation by supporting an active conformational state of RNA pol II.","method":"Point mutagenesis; in vitro transcription and elongation assays; binding affinity measurements; Arrhenius analysis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — mutagenesis with multiple orthogonal methods (kinetics, affinity, thermodynamics) in single study","pmids":["10567562"],"is_preprint":false},{"year":1999,"finding":"RAP74 subunit co-localizes with productively transcribing RNA pol II on Chironomus polytene chromosomes; both RAP74 and CK2alpha are sensitive to DRB treatment, suggesting RAP74 travels with elongating pol II along the DNA template, and DRB may block transcription by interfering with TFIIF recruitment through CK2alpha-mediated phosphorylation of RAP74.","method":"Immunofluorescence on polytene chromosomes; DRB treatment; co-localization with pol II","journal":"Molecular and cellular biochemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct localization by immunostaining on polytene chromosomes with pharmacological perturbation, but mechanism is partly inferential","pmids":["10094404"],"is_preprint":false},{"year":2000,"finding":"The crystal structure of the RAP30/RAP74 interaction domains at 1.7 Å resolution reveals a novel 'triple barrel' dimerization fold; mutagenesis data indicate that interactions with the transcription apparatus are mediated by the tripartite beta-barrel and via flexible loops and alpha/beta structures extending from it.","method":"X-ray crystallography at 1.7 Å; mutagenesis","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structure combined with mutagenesis functional validation","pmids":["11183778"],"is_preprint":false},{"year":2000,"finding":"RAP74 is phosphorylated by TAFII250 during Tat-activated HIV-1 LTR transcription; depletion of RAP74 from HeLa nuclear extract inhibits both basal transcription and Tat transactivation, and reconstitution with recombinant TFIIF restores activity; exogenous RAP74 is rapidly phosphorylated in the presence of Tat.","method":"Biotinylated DNA template transcription assay; RAP74 depletion and reconstitution; in vitro phosphorylation assay","journal":"Virology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — depletion/reconstitution combined with in vitro phosphorylation, single lab","pmids":["10704353"],"is_preprint":false},{"year":2001,"finding":"The crystal structure of the C-terminal domain of RAP74 at 1.02 Å resolution reveals a winged-helix fold similar to linker histone H5 and HNF-3gamma; a putative FCP1 phosphatase binding site was identified within this winged-helix domain.","method":"X-ray crystallography at 1.02 Å resolution","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — atomic-resolution crystal structure with identification of protein-protein interaction surface","pmids":["11248041"],"is_preprint":false},{"year":2002,"finding":"The alpha1 helix of RAP74 (aa ~155–177) is critical for both initiation and elongation stimulation; mutations within the alpha1 helix decrease transcription activities without affecting RAP30 binding or TFIIF–pol II interaction; contacts between the beta4-beta5 loop and alpha1 helix are not important for alpha1 helix function.","method":"Point mutagenesis guided by crystal structure; in vitro transcription and elongation assays; binding assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — structure-guided mutagenesis with multiple in vitro functional assays","pmids":["12354769"],"is_preprint":false},{"year":2003,"finding":"The NMR solution structure of the C-terminal domain of RAP74 (cterRAP74, residues 436–517) was determined; cterFCP binds in a groove between alpha-helices H2 and H3 of cterRAP74 without altering the secondary structure of RAP74; both RAP74 and TFIIB use shallow hydrophobic/positively-charged grooves to bind FCP1's acidic C-terminal domain.","method":"NMR solution structure determination; chemical shift mapping","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — NMR structure with binding interface mapping, consistent with companion structural studies","pmids":["12578358"],"is_preprint":false},{"year":2003,"finding":"High-resolution NMR structure of the cterRAP74–cterFCP1 complex shows that the disordered cterFCP1 forms an alpha-helix (H1') upon binding; the interface relies on van der Waals contacts between hydrophobic residues of RAP74 H2/H3 helices and the FCP1 H1' helix, plus critical electrostatic interactions between FCP1 aspartate residues and RAP74 lysines.","method":"NMR structure determination of protein complex","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution NMR complex structure with detailed interaction analysis, consistent with multiple structural studies","pmids":["12732728"],"is_preprint":false},{"year":2005,"finding":"CK2 phosphorylates FCP1 at T584 (central domain) and S942/S944 (C-terminal domain), which enhances binding of RAP74 to FCP1; NMR chemical shift mapping confirmed that phosphorylated FCP1 peptides interact with the same groove of cterRAP74 (H2/H3 helices); HIV-1 Tat inhibits the CK2-mediated phosphorylation and RAP74 binding to FCP1.","method":"In vitro CK2 kinase assay; NMR chemical shift mapping; FT-ICR mass spectrometry; in vitro binding assays","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple orthogonal methods (kinase assay, NMR, MS) characterizing the same interaction in two companion papers","pmids":["15723518","15723517"],"is_preprint":false},{"year":2005,"finding":"The RAP74 alpha1 helix promotes forward translocation of RNA pol II during elongation; deletion of the alpha1 helix (RAP74(1-158)) results in increased occupancy of backtracking/cleavage/restart pathways and failure to support NTP-driven translocation from a stall position.","method":"Millisecond-phase transient-state kinetics; deletion mutagenesis; elongation complex analysis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — transient-state kinetic analysis with deletion mutants and two-bond kinetic simulations","pmids":["15831464"],"is_preprint":false},{"year":2009,"finding":"NMR structure of the cterRAP74–centFCP1(phosphorylated) complex shows that the central domain of FCP1 uses hydrophobic and acidic residues to recognize the same groove of RAP74 as cterFCP1, but with significant mechanistic differences, demonstrating adaptability of RAP74 in recognizing two distinct FCP1 regions.","method":"NMR structure determination; isothermal titration calorimetry","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — NMR structure plus thermodynamic characterization (ITC) of protein complex","pmids":["19215094"],"is_preprint":false},{"year":2012,"finding":"NMR spin relaxation analysis shows that the C-terminal tail of FCP1 undergoes local folding-upon-binding at the ~20 residues forming direct contact with RAP74, while most of FCP1 remains highly dynamic in both bound and unbound states; RAP74 shows only very limited ordering upon FCP1 binding.","method":"Carbon-detected 15N NMR spin relaxation (CON(T1)-IPAP and CON(T2)-IPAP experiments)","journal":"The journal of physical chemistry letters","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — novel NMR methodology applied to the RAP74-FCP1 complex, single lab, single study","pmids":["26286791"],"is_preprint":false},{"year":2021,"finding":"Charged residues flanking the FCP1 binding helix form transient electrostatic interactions with the winged-helix domain of RAP74; charge inversion mutations in FCP1 affect the conformational ensemble of the complex but have minimal impact on overall binding affinity, indicating hydrophobic interactions in the minimal binding motif are the primary driving force.","method":"Paramagnetic relaxation enhancement (PRE) NMR; charge inversion mutagenesis; binding affinity measurements","journal":"The journal of physical chemistry. B","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — NMR PRE with mutagenesis, single lab, single study","pmids":["34550709"],"is_preprint":false}],"current_model":"GTF2F1 (RAP74) is the large subunit of general transcription factor TFIIF, which forms an alpha2beta2 heterotetramer with RAP30 via a novel triple-barrel dimerization fold; RAP74 recruits RNA polymerase II into the preinitiation complex through its N-terminal domain, facilitates promoter DNA unwinding and preinitiation complex isomerization via its alpha1 helix, stimulates forward translocation during elongation, and its C-terminal winged-helix domain binds and stimulates the CTD phosphatase FCP1 (whose binding is enhanced by CK2 phosphorylation) to enable RNA pol II recycling; RAP74 is also phosphorylated by TAFII250 in a cell-cycle-dependent manner and serves as a direct target for transcriptional activators such as SRF."},"narrative":{"mechanistic_narrative":"GTF2F1 (RAP74) is the large subunit of the general transcription factor TFIIF, which reconstitutes accurate RNA polymerase II transcription initiation in vitro together with the small subunit RAP30 [PMID:1734284, PMID:7929273]. RAP74 binds RAP30 through its N-terminal domain (aa 1–172) and uses this region to recruit RNA pol II into the preinitiation complex, where it associates with promoter DNA on both sides of the TATA-box bend and induces a conformational change in the position of pol II relative to DNA [PMID:7592953, PMID:9207059, PMID:9528785]. A central alpha1 helix (aa ~155–177) is critical for preinitiation complex isomerization and formation of the first phosphodiester bond, and the requirement for this region is partially relieved by negative supercoiling, indicating that RAP74 assists in untwisting promoter DNA during initiation [PMID:10523626, PMID:10567562]. The same alpha1 helix drives forward translocation of pol II during elongation, suppressing backtracking and restart pathways, consistent with RAP74 supporting an active elongating conformation of the polymerase [PMID:10567562, PMID:15831464]. Through its C-terminal winged-helix domain, RAP74 binds and stimulates the CTD phosphatase FCP1 to enable pol II recycling, recognizing distinct FCP1 regions through a hydrophobic groove between helices H2 and H3, with CK2 phosphorylation of FCP1 enhancing this interaction [PMID:9765293, PMID:11248041, PMID:12732728, PMID:15723518, PMID:15723517]. RAP74 is itself phosphorylated by the TFIID subunit TAFII250 in a cell-cycle-dependent manner, which increases TFIIF transcription activity, and it serves as a direct binding target for transcriptional activators such as SRF [PMID:7854423, PMID:8625415, PMID:9237686]. Structural studies established that the RAP30/RAP74 dimerization domains form a novel triple-barrel fold [PMID:11183778].","teleology":[{"year":1992,"claim":"Established that RAP74 is the large TFIIF subunit and an obligate component of the pol II machinery, answering whether it is genuinely required for accurate initiation.","evidence":"In vitro transcription reconstitution with recombinant RAP74/RAP30 and biochemical fractionation","pmids":["1734284"],"confidence":"High","gaps":["Did not resolve which RAP74 domains mediate each function","No structural information on the complex"]},{"year":1994,"claim":"Showed RAP74 contributes to multiple stages — stable preinitiation intermediate formation, first bond synthesis, and elongation rate — defining TFIIF as a multifunctional factor rather than an initiation-only factor.","evidence":"Highly purified in vitro transcription and kinetic elongation assays with reconstituted TFIIF","pmids":["7929273"],"confidence":"High","gaps":["Did not map which residues drive elongation versus initiation","Mechanism of elongation stimulation unresolved"]},{"year":1995,"claim":"Mapped RAP74's functional architecture and identified protein partners (TAFII250, SRF), establishing that distinct domains recruit pol II, bind RAP30, and interface with activators.","evidence":"Deletion mutagenesis with in vitro binding/transcription assays; yeast two-hybrid; in vivo complementation of ts-TAFII250 cells","pmids":["7592953","7590250","7854423"],"confidence":"High","gaps":["SRF interaction characterized in a single lab by two-hybrid and in vitro transcription only","No structure of any RAP74 domain yet"]},{"year":1996,"claim":"Identified TAFII250 as a serine kinase that selectively phosphorylates RAP74, linking the basal machinery to a regulatory phosphorylation event.","evidence":"In vitro kinase assay with recombinant TAFII250 and RAP74; kinase-domain deletion analysis","pmids":["8625415"],"confidence":"High","gaps":["Phosphosite mapping incomplete","Functional consequence of phosphorylation not yet defined"]},{"year":1997,"claim":"Localized RAP74 within the preinitiation complex relative to promoter DNA and showed cell-cycle-dependent phosphorylation (aa 206–256) increases TFIIF activity, connecting RAP74 regulation to the cell cycle.","evidence":"Site-specific protein-DNA photo-crosslinking; in vitro kinase assays with synchronized HeLa TFIID fractions and deletion mutants","pmids":["9207059","9237686"],"confidence":"Medium","gaps":["Crosslinking and kinase data each from single labs","In vivo relevance of cell-cycle phosphorylation not established"]},{"year":1998,"claim":"Resolved the division of labor between RAP74 domains and identified FCP1 as a C-terminal-domain partner, connecting RAP74 to CTD dephosphorylation and pol II recycling.","evidence":"Deletion mutagenesis with single/multiple-round in vitro transcription; yeast two-hybrid screen and in vitro phosphatase assay","pmids":["9528785","9765293"],"confidence":"High","gaps":["Structural basis of RAP74–FCP1 binding not yet defined","How CTD dephosphorylation couples to recycling unresolved"]},{"year":1999,"claim":"Pinpointed the alpha1 helix (T154–M177) as the element required for initiation and elongation stimulation and showed supercoiling rescue, supporting a DNA-untwisting role in initiation.","evidence":"Point mutagenesis; in vitro transcription, complex assembly, supercoiling-rescue and elongation/kinetic assays; polytene chromosome immunofluorescence with DRB","pmids":["10523626","10567562","10094404"],"confidence":"Medium","gaps":["DRB/CK2alpha link to RAP74 recruitment partly inferential","In vivo elongation function not directly tested in mammalian cells"]},{"year":2000,"claim":"Provided the first structural views — the triple-barrel RAP30/RAP74 dimerization fold — and demonstrated RAP74 phosphorylation operates during Tat-activated HIV-1 transcription.","evidence":"X-ray crystallography at 1.7 Å with mutagenesis; biotinylated-template transcription with depletion/reconstitution and in vitro phosphorylation","pmids":["11183778","10704353"],"confidence":"High","gaps":["Structure covers only the dimerization domains","Mechanism by which Tat engages RAP74 phosphorylation unresolved"]},{"year":2001,"claim":"Determined the RAP74 C-terminal winged-helix structure and located the FCP1 binding surface, giving a structural basis for the phosphatase interaction.","evidence":"X-ray crystallography of the C-terminal domain at 1.02 Å","pmids":["11248041"],"confidence":"High","gaps":["FCP1-binding site predicted, not yet co-crystallized","No information on bound FCP1 conformation"]},{"year":2003,"claim":"Solved the cterRAP74–cterFCP1 complex by NMR, showing FCP1 folds upon binding into the H2/H3 groove of RAP74 via hydrophobic and electrostatic contacts.","evidence":"NMR solution structure and structure of the protein complex with chemical shift mapping","pmids":["12578358","12732728"],"confidence":"High","gaps":["Did not address regulation of the interaction","Only the C-terminal FCP1 region examined"]},{"year":2005,"claim":"Linked CK2 phosphorylation of FCP1 to enhanced RAP74 binding and showed the RAP74 alpha1 helix actively promotes forward pol II translocation, mechanistically defining its elongation function.","evidence":"In vitro CK2 kinase assay, NMR chemical shift mapping and MS; transient-state kinetics with alpha1-helix deletion mutants","pmids":["15723518","15723517","15831464"],"confidence":"High","gaps":["In vivo significance of CK2-regulated recycling not tested","Structural state of translocating complex not captured"]},{"year":2009,"claim":"Demonstrated RAP74 recognizes two distinct FCP1 regions through the same groove, revealing adaptability in the phosphatase interaction.","evidence":"NMR structure of the cterRAP74–phospho-centFCP1 complex with ITC","pmids":["19215094"],"confidence":"High","gaps":["Functional consequence of dual-region recognition unresolved","Order of engagement of the two FCP1 regions unknown"]},{"year":2021,"claim":"Characterized the dynamic, fuzzy nature of the RAP74–FCP1 interface, showing hydrophobic contacts dominate binding while flanking charges tune the conformational ensemble.","evidence":"NMR spin relaxation and paramagnetic relaxation enhancement with charge-inversion mutagenesis and affinity measurements","pmids":["26286791","34550709"],"confidence":"Medium","gaps":["Single-lab biophysical studies","Functional impact of interface dynamics on dephosphorylation not measured"]},{"year":null,"claim":"How RAP74's biochemically defined initiation, elongation, and recycling functions operate and are regulated in living human cells remains unresolved.","evidence":"No in vivo loss-of-function or genome-wide functional study appears in the corpus","pmids":[],"confidence":"Low","gaps":["No cellular knockdown/knockout phenotype documented","No genome-wide occupancy data in the corpus","No disease association reported"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0,1,3]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[6,10]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[8,11,20]}],"localization":[{"term_id":"GO:0005654","term_label":"nucleoplasm","supporting_discovery_ids":[6,12]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[12]}],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[0,1,9]}],"complexes":["TFIIF (RAP30/RAP74)","RNA polymerase II preinitiation complex"],"partners":["GTF2F2","TAF1","FCP1","SRF","CSNK2A1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P35269","full_name":"General transcription factor IIF subunit 1","aliases":["General transcription factor IIF 74 kDa subunit","Transcription initiation factor IIF subunit alpha","TFIIF-alpha","Transcription initiation factor RAP74"],"length_aa":517,"mass_kda":58.2,"function":"TFIIF is a general transcription initiation factor that binds to RNA polymerase II and helps to recruit it to the initiation complex in collaboration with TFIIB. It promotes transcription elongation","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/P35269/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/GTF2F1","classification":"Common Essential","n_dependent_lines":743,"n_total_lines":1208,"dependency_fraction":0.6150662251655629},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000125651","cell_line_id":"CID001928","localizations":[{"compartment":"nucleolus_gc","grade":3},{"compartment":"nucleoplasm","grade":3}],"interactors":[{"gene":"POLR2K","stoichiometry":10.0},{"gene":"POLR2B","stoichiometry":10.0},{"gene":"POLR2G","stoichiometry":4.0},{"gene":"POLR2D","stoichiometry":4.0},{"gene":"POLR2A","stoichiometry":4.0},{"gene":"POLR2E","stoichiometry":4.0},{"gene":"POLR2F","stoichiometry":0.2},{"gene":"TBP","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001928","total_profiled":1310},"omim":[{"mim_id":"606007","title":"POLYMERASE III, RNA, SUBUNIT K; POLR3K","url":"https://www.omim.org/entry/606007"},{"mim_id":"605323","title":"C-TERMINAL DOMAIN OF RNA POLYMERASE II POLYPEPTIDE A, SMALL PHOSPHATASE OF, 1; CTDSP1","url":"https://www.omim.org/entry/605323"},{"mim_id":"604927","title":"C-TERMINAL DOMAIN OF RNA POLYMERASE II SUBUNIT A, PHOSPHATASE OF, SUBUNIT 1; CTDP1","url":"https://www.omim.org/entry/604927"},{"mim_id":"602955","title":"TAF6 RNA POLYMERASE II, TATA BOX-BINDING PROTEIN-ASSOCIATED FACTOR, 80-KD; TAF6","url":"https://www.omim.org/entry/602955"},{"mim_id":"600475","title":"TAF10 RNA POLYMERASE II, TATA BOX-BINDING PROTEIN-ASSOCIATED FACTOR, 30-KD; TAF10","url":"https://www.omim.org/entry/600475"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/GTF2F1"},"hgnc":{"alias_symbol":["TFIIF","BTF4","RAP74","TF2F1"],"prev_symbol":[]},"alphafold":{"accession":"P35269","domains":[{"cath_id":"-","chopping":"17-154","consensus_level":"high","plddt":81.8225,"start":17,"end":154},{"cath_id":"1.10.10.10","chopping":"457-515","consensus_level":"high","plddt":85.3939,"start":457,"end":515}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P35269","model_url":"https://alphafold.ebi.ac.uk/files/AF-P35269-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P35269-F1-predicted_aligned_error_v6.png","plddt_mean":62.28},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GTF2F1","jax_strain_url":"https://www.jax.org/strain/search?query=GTF2F1"},"sequence":{"accession":"P35269","fasta_url":"https://rest.uniprot.org/uniprotkb/P35269.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P35269/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P35269"}},"corpus_meta":[{"pmid":"8625415","id":"PMC_8625415","title":"TAFII250 is a bipartite protein kinase that phosphorylates the base transcription factor RAP74.","date":"1996","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/8625415","citation_count":184,"is_preprint":false},{"pmid":"9765293","id":"PMC_9765293","title":"FCP1, the RAP74-interacting subunit of a human protein phosphatase that dephosphorylates the carboxyl-terminal domain of RNA polymerase IIO.","date":"1998","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9765293","citation_count":128,"is_preprint":false},{"pmid":"1734284","id":"PMC_1734284","title":"A cDNA encoding RAP74, a general initiation factor for transcription by RNA polymerase II.","date":"1992","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/1734284","citation_count":96,"is_preprint":false},{"pmid":"7929273","id":"PMC_7929273","title":"Roles for both the RAP30 and RAP74 subunits of transcription factor IIF in transcription initiation and elongation by RNA polymerase II.","date":"1994","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/7929273","citation_count":87,"is_preprint":false},{"pmid":"7854423","id":"PMC_7854423","title":"Interaction with RAP74 subunit of TFIIF is required for transcriptional activation by serum response factor.","date":"1995","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/7854423","citation_count":79,"is_preprint":false},{"pmid":"11183778","id":"PMC_11183778","title":"Novel dimerization fold of RAP30/RAP74 in human TFIIF at 1.7 A resolution.","date":"2000","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/11183778","citation_count":72,"is_preprint":false},{"pmid":"8390879","id":"PMC_8390879","title":"Production of human RAP30 and RAP74 in bacterial cells.","date":"1993","source":"Protein expression and purification","url":"https://pubmed.ncbi.nlm.nih.gov/8390879","citation_count":54,"is_preprint":false},{"pmid":"7590250","id":"PMC_7590250","title":"Human TAFII250 interacts with RAP74: implications for RNA polymerase II initiation.","date":"1995","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/7590250","citation_count":54,"is_preprint":false},{"pmid":"9207059","id":"PMC_9207059","title":"RAP74 induces promoter contacts by RNA polymerase II upstream and downstream of a DNA bend centered on the TATA box.","date":"1997","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/9207059","citation_count":52,"is_preprint":false},{"pmid":"7592953","id":"PMC_7592953","title":"Functional domains of human RAP74 including a masked polymerase binding domain.","date":"1995","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/7592953","citation_count":46,"is_preprint":false},{"pmid":"11248041","id":"PMC_11248041","title":"Crystal structure of the C-terminal domain of the RAP74 subunit of human transcription factor IIF.","date":"2001","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/11248041","citation_count":42,"is_preprint":false},{"pmid":"9528785","id":"PMC_9528785","title":"Functions of the N- and C-terminal domains of human RAP74 in transcriptional initiation, elongation, and recycling of RNA polymerase II.","date":"1998","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/9528785","citation_count":41,"is_preprint":false},{"pmid":"7827505","id":"PMC_7827505","title":"Importance of codon preference for production of human RAP74 and reconstitution of the RAP30/74 complex.","date":"1994","source":"Protein expression and purification","url":"https://pubmed.ncbi.nlm.nih.gov/7827505","citation_count":40,"is_preprint":false},{"pmid":"12732728","id":"PMC_12732728","title":"NMR structure of a complex containing the TFIIF subunit RAP74 and the RNA polymerase II carboxyl-terminal domain phosphatase FCP1.","date":"2003","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/12732728","citation_count":36,"is_preprint":false},{"pmid":"26286791","id":"PMC_26286791","title":"Carbon-Detected (15)N NMR Spin Relaxation of an Intrinsically Disordered Protein: FCP1 Dynamics Unbound and in Complex with RAP74.","date":"2012","source":"The journal of physical chemistry letters","url":"https://pubmed.ncbi.nlm.nih.gov/26286791","citation_count":28,"is_preprint":false},{"pmid":"10567562","id":"PMC_10567562","title":"The RAP74 subunit of human transcription factor IIF has similar roles in initiation and elongation.","date":"1999","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/10567562","citation_count":26,"is_preprint":false},{"pmid":"15831464","id":"PMC_15831464","title":"Human RNA polymerase II elongation in slow motion: role of the TFIIF RAP74 alpha1 helix in nucleoside triphosphate-driven translocation.","date":"2005","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15831464","citation_count":24,"is_preprint":false},{"pmid":"10523626","id":"PMC_10523626","title":"A region within the RAP74 subunit of human transcription factor IIF is critical for initiation but dispensable for complex assembly.","date":"1999","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/10523626","citation_count":23,"is_preprint":false},{"pmid":"23921640","id":"PMC_23921640","title":"RNA polymerase III-specific general transcription factor IIIC contains a heterodimer resembling TFIIF Rap30/Rap74.","date":"2013","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/23921640","citation_count":22,"is_preprint":false},{"pmid":"10094404","id":"PMC_10094404","title":"The binding of the alpha subunit of protein kinase CK2 and RAP74 subunit of TFIIF to protein-coding genes in living cells is DRB sensitive.","date":"1999","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10094404","citation_count":21,"is_preprint":false},{"pmid":"15723518","id":"PMC_15723518","title":"Enhanced binding of RNAP II CTD phosphatase FCP1 to RAP74 following CK2 phosphorylation.","date":"2005","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15723518","citation_count":20,"is_preprint":false},{"pmid":"12354769","id":"PMC_12354769","title":"A key role for the alpha 1 helix of human RAP74 in the initiation and elongation of RNA chains.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12354769","citation_count":18,"is_preprint":false},{"pmid":"21988473","id":"PMC_21988473","title":"Atomistic simulations reveal structural disorder in the RAP74-FCP1 complex.","date":"2011","source":"The journal of physical chemistry. B","url":"https://pubmed.ncbi.nlm.nih.gov/21988473","citation_count":17,"is_preprint":false},{"pmid":"15723517","id":"PMC_15723517","title":"Interactions of the HIV-1 Tat and RAP74 proteins with the RNA polymerase II CTD phosphatase FCP1.","date":"2005","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/15723517","citation_count":16,"is_preprint":false},{"pmid":"12578358","id":"PMC_12578358","title":"Solution structure of the carboxyl-terminal domain of RAP74 and NMR characterization of the FCP1-binding sites of RAP74 and human TFIIB.","date":"2003","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12578358","citation_count":16,"is_preprint":false},{"pmid":"19215094","id":"PMC_19215094","title":"NMR structure of a complex formed by the carboxyl-terminal domain of human RAP74 and a phosphorylated peptide from the central domain of the FCP1 phosphatase.","date":"2009","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19215094","citation_count":13,"is_preprint":false},{"pmid":"10704353","id":"PMC_10704353","title":"Phosphorylation of the RAP74 subunit of TFIIF correlates with Tat-activated transcription of the HIV-1 long terminal repeat.","date":"2000","source":"Virology","url":"https://pubmed.ncbi.nlm.nih.gov/10704353","citation_count":13,"is_preprint":false},{"pmid":"23387368","id":"PMC_23387368","title":"Native-based simulations of the binding interaction between RAP74 and the disordered FCP1 peptide.","date":"2013","source":"The journal of physical chemistry. B","url":"https://pubmed.ncbi.nlm.nih.gov/23387368","citation_count":11,"is_preprint":false},{"pmid":"9237686","id":"PMC_9237686","title":"Cell-cycle-dependent phosphorylation of the basal transcription factor RAP74.","date":"1997","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/9237686","citation_count":7,"is_preprint":false},{"pmid":"8486367","id":"PMC_8486367","title":"Assignment of the human GTF2F1 gene to chromosome 19p13.3.","date":"1993","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/8486367","citation_count":5,"is_preprint":false},{"pmid":"34550709","id":"PMC_34550709","title":"Transient Electrostatic Interactions between Fcp1 and Rap74 Bias the Conformational Ensemble of the Complex with Minimal Impact on Binding Affinity.","date":"2021","source":"The journal of physical chemistry. B","url":"https://pubmed.ncbi.nlm.nih.gov/34550709","citation_count":2,"is_preprint":false},{"pmid":"7948016","id":"PMC_7948016","title":"Enhancement of bacterial transcription initiation in vitro by the 74 kDa subunit of human general transcription factor IIF (RAP74).","date":"1994","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/7948016","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":15484,"output_tokens":5308,"usd":0.063036,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":13712,"output_tokens":4023,"usd":0.084568,"stage2_stop_reason":"end_turn"},"total_usd":0.147604,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1992,\n      \"finding\": \"RAP74 (GTF2F1) is the large subunit of the TFIIF (RAP30/74) complex; recombinant RAP74 produced in E. coli, together with RAP30, reconstitutes accurate transcription initiation by RNA polymerase II in vitro, and both RAP30 and RAP74 are physical components of the preinitiation complex.\",\n      \"method\": \"In vitro transcription reconstitution with recombinant proteins; biochemical fractionation\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution of accurate transcription with recombinant subunits, replicated in subsequent studies\",\n      \"pmids\": [\"1734284\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"Both RAP30 and RAP74 subunits of TFIIF contribute to formation of stable preinitiation intermediates containing RNA polymerase II, synthesis of the first phosphodiester bonds during initiation, and stimulation of the rate of RNA chain elongation.\",\n      \"method\": \"Highly purified in vitro transcription system; template competition experiments; kinetic elongation assays with reconstituted TFIIF\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with multiple orthogonal functional assays (initiation, elongation, preinitiation complex formation)\",\n      \"pmids\": [\"7929273\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"TAFII250 specifically interacts with RAP74 in vitro, and this interaction is critical for cell viability as shown by in vivo complementation of a temperature-sensitive TAFII250 cell line; the interaction domain on RAP74 was mapped by in vitro binding assays.\",\n      \"method\": \"In vitro binding assays (pulldown/co-IP); in vivo complementation of ts-TAFII250 cell line\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal binding assays plus in vivo functional complementation, replicated with the kinase study\",\n      \"pmids\": [\"7590250\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"RAP74's central charged cluster domain binds the transcriptional activation domain of serum response factor (SRF); deletion of this domain impairs SRF-activated but not basal or SP1-activated transcription in vitro.\",\n      \"method\": \"Yeast two-hybrid interaction assay; in vitro transcription with RAP74 deletion mutants\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid plus functional in vitro transcription assay, single lab\",\n      \"pmids\": [\"7854423\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Deletion mutagenesis of RAP74 mapped its RAP30-binding domain to amino acids 1–172, identified a partially masked RNA polymerase II binding domain at the C-terminal region (aa 363–444), and showed that aa 1–205 are minimally sufficient to stimulate accurate transcription in vitro.\",\n      \"method\": \"Deletion mutagenesis; in vitro binding and transcription assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — systematic deletion mutagenesis combined with multiple in vitro functional assays in the same study\",\n      \"pmids\": [\"7592953\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"TAFII250 is a protein serine kinase that selectively phosphorylates RAP74 but not other basal transcription factors; TAFII250 contains two distinct kinase domains, both required for efficient transphosphorylation of RAP74, and phosphorylation occurs in the context of the complete TFIID complex.\",\n      \"method\": \"In vitro kinase assay with purified recombinant TAFII250 and RAP74; deletion analysis of TAFII250 kinase domains\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro kinase reconstitution with mutagenesis/deletion analysis, multiple controls\",\n      \"pmids\": [\"8625415\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"RAP74 associates with the preinitiation complex in close proximity to promoter DNA both upstream and downstream of a DNA bend centered on the TATA box, and binding of RAP74 induces a conformational change affecting the position of RNA pol II relative to DNA; the N-terminal region containing the RAP30-binding domain is minimally required.\",\n      \"method\": \"Site-specific protein-DNA photo-crosslinking; deletion analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct crosslinking mapping of RAP74 position in PIC, single lab\",\n      \"pmids\": [\"9207059\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Cell-cycle-dependent phosphorylation of RAP74 by TFIID (S/G2-phase fraction) targets amino acid residues 206–256, and this phosphorylation increases TFIIF transcription activity in vitro.\",\n      \"method\": \"In vitro kinase assay with synchronized HeLa cell TFIID fractions; RAP74 deletion mutants; in vitro transcription reconstitution\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro kinase and transcription assays, single lab, single study\",\n      \"pmids\": [\"9237686\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"FCP1 interacts with the carboxyl-terminal evolutionarily conserved domain of RAP74 (identified by yeast two-hybrid screen); FCP1 is an essential subunit of a RAP74-stimulated phosphatase that processively dephosphorylates the CTD of RNA pol II.\",\n      \"method\": \"Yeast two-hybrid screen; biochemical phosphatase assay with purified proteins\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — yeast two-hybrid identification plus in vitro phosphatase reconstitution assay, replicated in multiple subsequent studies\",\n      \"pmids\": [\"9765293\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"The N-terminal domain of RAP74 (aa 1–172) is sufficient to recruit RNA pol II into the preinitiation complex; the region aa 172–205 (and specifically aa 170–178) is critical for both accurate initiation and elongation; the C-terminal domain does not contribute strongly to single-round initiation or elongation but stimulates multiple-round transcription.\",\n      \"method\": \"Deletion mutagenesis; in vitro transcription assays (single-round and multiple-round); preinitiation complex assembly assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — systematic deletion mutagenesis with multiple in vitro transcription assays distinguishing functional domains\",\n      \"pmids\": [\"9528785\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"The region of RAP74 between L155 and M177 is critical for initiation (formation of first phosphodiester bond) but is not required for complex assembly or polymerase II recruitment; negative DNA supercoiling partially compensates for defects in this region, suggesting TFIIF helps untwist DNA for initiation.\",\n      \"method\": \"Point mutagenesis; in vitro transcription assays; preinitiation complex assembly assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — systematic mutagenesis with orthogonal in vitro assays (transcription initiation, complex assembly, supercoiling rescue)\",\n      \"pmids\": [\"10523626\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"RAP74 region aa T154–M177 (alpha1 helix region) is critical for isomerization of the preinitiation complex and for elongation stimulation; TFIIF has higher affinity for rapidly elongating RNA pol II than for stalled elongation complexes; TFIIF stimulates elongation by supporting an active conformational state of RNA pol II.\",\n      \"method\": \"Point mutagenesis; in vitro transcription and elongation assays; binding affinity measurements; Arrhenius analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — mutagenesis with multiple orthogonal methods (kinetics, affinity, thermodynamics) in single study\",\n      \"pmids\": [\"10567562\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"RAP74 subunit co-localizes with productively transcribing RNA pol II on Chironomus polytene chromosomes; both RAP74 and CK2alpha are sensitive to DRB treatment, suggesting RAP74 travels with elongating pol II along the DNA template, and DRB may block transcription by interfering with TFIIF recruitment through CK2alpha-mediated phosphorylation of RAP74.\",\n      \"method\": \"Immunofluorescence on polytene chromosomes; DRB treatment; co-localization with pol II\",\n      \"journal\": \"Molecular and cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct localization by immunostaining on polytene chromosomes with pharmacological perturbation, but mechanism is partly inferential\",\n      \"pmids\": [\"10094404\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"The crystal structure of the RAP30/RAP74 interaction domains at 1.7 Å resolution reveals a novel 'triple barrel' dimerization fold; mutagenesis data indicate that interactions with the transcription apparatus are mediated by the tripartite beta-barrel and via flexible loops and alpha/beta structures extending from it.\",\n      \"method\": \"X-ray crystallography at 1.7 Å; mutagenesis\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structure combined with mutagenesis functional validation\",\n      \"pmids\": [\"11183778\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"RAP74 is phosphorylated by TAFII250 during Tat-activated HIV-1 LTR transcription; depletion of RAP74 from HeLa nuclear extract inhibits both basal transcription and Tat transactivation, and reconstitution with recombinant TFIIF restores activity; exogenous RAP74 is rapidly phosphorylated in the presence of Tat.\",\n      \"method\": \"Biotinylated DNA template transcription assay; RAP74 depletion and reconstitution; in vitro phosphorylation assay\",\n      \"journal\": \"Virology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — depletion/reconstitution combined with in vitro phosphorylation, single lab\",\n      \"pmids\": [\"10704353\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The crystal structure of the C-terminal domain of RAP74 at 1.02 Å resolution reveals a winged-helix fold similar to linker histone H5 and HNF-3gamma; a putative FCP1 phosphatase binding site was identified within this winged-helix domain.\",\n      \"method\": \"X-ray crystallography at 1.02 Å resolution\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — atomic-resolution crystal structure with identification of protein-protein interaction surface\",\n      \"pmids\": [\"11248041\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The alpha1 helix of RAP74 (aa ~155–177) is critical for both initiation and elongation stimulation; mutations within the alpha1 helix decrease transcription activities without affecting RAP30 binding or TFIIF–pol II interaction; contacts between the beta4-beta5 loop and alpha1 helix are not important for alpha1 helix function.\",\n      \"method\": \"Point mutagenesis guided by crystal structure; in vitro transcription and elongation assays; binding assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — structure-guided mutagenesis with multiple in vitro functional assays\",\n      \"pmids\": [\"12354769\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"The NMR solution structure of the C-terminal domain of RAP74 (cterRAP74, residues 436–517) was determined; cterFCP binds in a groove between alpha-helices H2 and H3 of cterRAP74 without altering the secondary structure of RAP74; both RAP74 and TFIIB use shallow hydrophobic/positively-charged grooves to bind FCP1's acidic C-terminal domain.\",\n      \"method\": \"NMR solution structure determination; chemical shift mapping\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — NMR structure with binding interface mapping, consistent with companion structural studies\",\n      \"pmids\": [\"12578358\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"High-resolution NMR structure of the cterRAP74–cterFCP1 complex shows that the disordered cterFCP1 forms an alpha-helix (H1') upon binding; the interface relies on van der Waals contacts between hydrophobic residues of RAP74 H2/H3 helices and the FCP1 H1' helix, plus critical electrostatic interactions between FCP1 aspartate residues and RAP74 lysines.\",\n      \"method\": \"NMR structure determination of protein complex\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution NMR complex structure with detailed interaction analysis, consistent with multiple structural studies\",\n      \"pmids\": [\"12732728\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"CK2 phosphorylates FCP1 at T584 (central domain) and S942/S944 (C-terminal domain), which enhances binding of RAP74 to FCP1; NMR chemical shift mapping confirmed that phosphorylated FCP1 peptides interact with the same groove of cterRAP74 (H2/H3 helices); HIV-1 Tat inhibits the CK2-mediated phosphorylation and RAP74 binding to FCP1.\",\n      \"method\": \"In vitro CK2 kinase assay; NMR chemical shift mapping; FT-ICR mass spectrometry; in vitro binding assays\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple orthogonal methods (kinase assay, NMR, MS) characterizing the same interaction in two companion papers\",\n      \"pmids\": [\"15723518\", \"15723517\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"The RAP74 alpha1 helix promotes forward translocation of RNA pol II during elongation; deletion of the alpha1 helix (RAP74(1-158)) results in increased occupancy of backtracking/cleavage/restart pathways and failure to support NTP-driven translocation from a stall position.\",\n      \"method\": \"Millisecond-phase transient-state kinetics; deletion mutagenesis; elongation complex analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — transient-state kinetic analysis with deletion mutants and two-bond kinetic simulations\",\n      \"pmids\": [\"15831464\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"NMR structure of the cterRAP74–centFCP1(phosphorylated) complex shows that the central domain of FCP1 uses hydrophobic and acidic residues to recognize the same groove of RAP74 as cterFCP1, but with significant mechanistic differences, demonstrating adaptability of RAP74 in recognizing two distinct FCP1 regions.\",\n      \"method\": \"NMR structure determination; isothermal titration calorimetry\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — NMR structure plus thermodynamic characterization (ITC) of protein complex\",\n      \"pmids\": [\"19215094\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"NMR spin relaxation analysis shows that the C-terminal tail of FCP1 undergoes local folding-upon-binding at the ~20 residues forming direct contact with RAP74, while most of FCP1 remains highly dynamic in both bound and unbound states; RAP74 shows only very limited ordering upon FCP1 binding.\",\n      \"method\": \"Carbon-detected 15N NMR spin relaxation (CON(T1)-IPAP and CON(T2)-IPAP experiments)\",\n      \"journal\": \"The journal of physical chemistry letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — novel NMR methodology applied to the RAP74-FCP1 complex, single lab, single study\",\n      \"pmids\": [\"26286791\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Charged residues flanking the FCP1 binding helix form transient electrostatic interactions with the winged-helix domain of RAP74; charge inversion mutations in FCP1 affect the conformational ensemble of the complex but have minimal impact on overall binding affinity, indicating hydrophobic interactions in the minimal binding motif are the primary driving force.\",\n      \"method\": \"Paramagnetic relaxation enhancement (PRE) NMR; charge inversion mutagenesis; binding affinity measurements\",\n      \"journal\": \"The journal of physical chemistry. B\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — NMR PRE with mutagenesis, single lab, single study\",\n      \"pmids\": [\"34550709\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GTF2F1 (RAP74) is the large subunit of general transcription factor TFIIF, which forms an alpha2beta2 heterotetramer with RAP30 via a novel triple-barrel dimerization fold; RAP74 recruits RNA polymerase II into the preinitiation complex through its N-terminal domain, facilitates promoter DNA unwinding and preinitiation complex isomerization via its alpha1 helix, stimulates forward translocation during elongation, and its C-terminal winged-helix domain binds and stimulates the CTD phosphatase FCP1 (whose binding is enhanced by CK2 phosphorylation) to enable RNA pol II recycling; RAP74 is also phosphorylated by TAFII250 in a cell-cycle-dependent manner and serves as a direct target for transcriptional activators such as SRF.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GTF2F1 (RAP74) is the large subunit of the general transcription factor TFIIF, which reconstitutes accurate RNA polymerase II transcription initiation in vitro together with the small subunit RAP30 [#0, #1]. RAP74 binds RAP30 through its N-terminal domain (aa 1–172) and uses this region to recruit RNA pol II into the preinitiation complex, where it associates with promoter DNA on both sides of the TATA-box bend and induces a conformational change in the position of pol II relative to DNA [#4, #6, #9]. A central alpha1 helix (aa ~155–177) is critical for preinitiation complex isomerization and formation of the first phosphodiester bond, and the requirement for this region is partially relieved by negative supercoiling, indicating that RAP74 assists in untwisting promoter DNA during initiation [#10, #11]. The same alpha1 helix drives forward translocation of pol II during elongation, suppressing backtracking and restart pathways, consistent with RAP74 supporting an active elongating conformation of the polymerase [#11, #20]. Through its C-terminal winged-helix domain, RAP74 binds and stimulates the CTD phosphatase FCP1 to enable pol II recycling, recognizing distinct FCP1 regions through a hydrophobic groove between helices H2 and H3, with CK2 phosphorylation of FCP1 enhancing this interaction [#8, #15, #18, #19]. RAP74 is itself phosphorylated by the TFIID subunit TAFII250 in a cell-cycle-dependent manner, which increases TFIIF transcription activity, and it serves as a direct binding target for transcriptional activators such as SRF [#3, #5, #7]. Structural studies established that the RAP30/RAP74 dimerization domains form a novel triple-barrel fold [#13].\",\n  \"teleology\": [\n    {\n      \"year\": 1992,\n      \"claim\": \"Established that RAP74 is the large TFIIF subunit and an obligate component of the pol II machinery, answering whether it is genuinely required for accurate initiation.\",\n      \"evidence\": \"In vitro transcription reconstitution with recombinant RAP74/RAP30 and biochemical fractionation\",\n      \"pmids\": [\"1734284\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve which RAP74 domains mediate each function\", \"No structural information on the complex\"]\n    },\n    {\n      \"year\": 1994,\n      \"claim\": \"Showed RAP74 contributes to multiple stages — stable preinitiation intermediate formation, first bond synthesis, and elongation rate — defining TFIIF as a multifunctional factor rather than an initiation-only factor.\",\n      \"evidence\": \"Highly purified in vitro transcription and kinetic elongation assays with reconstituted TFIIF\",\n      \"pmids\": [\"7929273\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not map which residues drive elongation versus initiation\", \"Mechanism of elongation stimulation unresolved\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Mapped RAP74's functional architecture and identified protein partners (TAFII250, SRF), establishing that distinct domains recruit pol II, bind RAP30, and interface with activators.\",\n      \"evidence\": \"Deletion mutagenesis with in vitro binding/transcription assays; yeast two-hybrid; in vivo complementation of ts-TAFII250 cells\",\n      \"pmids\": [\"7592953\", \"7590250\", \"7854423\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"SRF interaction characterized in a single lab by two-hybrid and in vitro transcription only\", \"No structure of any RAP74 domain yet\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Identified TAFII250 as a serine kinase that selectively phosphorylates RAP74, linking the basal machinery to a regulatory phosphorylation event.\",\n      \"evidence\": \"In vitro kinase assay with recombinant TAFII250 and RAP74; kinase-domain deletion analysis\",\n      \"pmids\": [\"8625415\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Phosphosite mapping incomplete\", \"Functional consequence of phosphorylation not yet defined\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Localized RAP74 within the preinitiation complex relative to promoter DNA and showed cell-cycle-dependent phosphorylation (aa 206–256) increases TFIIF activity, connecting RAP74 regulation to the cell cycle.\",\n      \"evidence\": \"Site-specific protein-DNA photo-crosslinking; in vitro kinase assays with synchronized HeLa TFIID fractions and deletion mutants\",\n      \"pmids\": [\"9207059\", \"9237686\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Crosslinking and kinase data each from single labs\", \"In vivo relevance of cell-cycle phosphorylation not established\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Resolved the division of labor between RAP74 domains and identified FCP1 as a C-terminal-domain partner, connecting RAP74 to CTD dephosphorylation and pol II recycling.\",\n      \"evidence\": \"Deletion mutagenesis with single/multiple-round in vitro transcription; yeast two-hybrid screen and in vitro phosphatase assay\",\n      \"pmids\": [\"9528785\", \"9765293\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of RAP74–FCP1 binding not yet defined\", \"How CTD dephosphorylation couples to recycling unresolved\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Pinpointed the alpha1 helix (T154–M177) as the element required for initiation and elongation stimulation and showed supercoiling rescue, supporting a DNA-untwisting role in initiation.\",\n      \"evidence\": \"Point mutagenesis; in vitro transcription, complex assembly, supercoiling-rescue and elongation/kinetic assays; polytene chromosome immunofluorescence with DRB\",\n      \"pmids\": [\"10523626\", \"10567562\", \"10094404\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"DRB/CK2alpha link to RAP74 recruitment partly inferential\", \"In vivo elongation function not directly tested in mammalian cells\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Provided the first structural views — the triple-barrel RAP30/RAP74 dimerization fold — and demonstrated RAP74 phosphorylation operates during Tat-activated HIV-1 transcription.\",\n      \"evidence\": \"X-ray crystallography at 1.7 Å with mutagenesis; biotinylated-template transcription with depletion/reconstitution and in vitro phosphorylation\",\n      \"pmids\": [\"11183778\", \"10704353\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure covers only the dimerization domains\", \"Mechanism by which Tat engages RAP74 phosphorylation unresolved\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Determined the RAP74 C-terminal winged-helix structure and located the FCP1 binding surface, giving a structural basis for the phosphatase interaction.\",\n      \"evidence\": \"X-ray crystallography of the C-terminal domain at 1.02 Å\",\n      \"pmids\": [\"11248041\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"FCP1-binding site predicted, not yet co-crystallized\", \"No information on bound FCP1 conformation\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Solved the cterRAP74–cterFCP1 complex by NMR, showing FCP1 folds upon binding into the H2/H3 groove of RAP74 via hydrophobic and electrostatic contacts.\",\n      \"evidence\": \"NMR solution structure and structure of the protein complex with chemical shift mapping\",\n      \"pmids\": [\"12578358\", \"12732728\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not address regulation of the interaction\", \"Only the C-terminal FCP1 region examined\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Linked CK2 phosphorylation of FCP1 to enhanced RAP74 binding and showed the RAP74 alpha1 helix actively promotes forward pol II translocation, mechanistically defining its elongation function.\",\n      \"evidence\": \"In vitro CK2 kinase assay, NMR chemical shift mapping and MS; transient-state kinetics with alpha1-helix deletion mutants\",\n      \"pmids\": [\"15723518\", \"15723517\", \"15831464\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo significance of CK2-regulated recycling not tested\", \"Structural state of translocating complex not captured\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Demonstrated RAP74 recognizes two distinct FCP1 regions through the same groove, revealing adaptability in the phosphatase interaction.\",\n      \"evidence\": \"NMR structure of the cterRAP74–phospho-centFCP1 complex with ITC\",\n      \"pmids\": [\"19215094\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of dual-region recognition unresolved\", \"Order of engagement of the two FCP1 regions unknown\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Characterized the dynamic, fuzzy nature of the RAP74–FCP1 interface, showing hydrophobic contacts dominate binding while flanking charges tune the conformational ensemble.\",\n      \"evidence\": \"NMR spin relaxation and paramagnetic relaxation enhancement with charge-inversion mutagenesis and affinity measurements\",\n      \"pmids\": [\"26286791\", \"34550709\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab biophysical studies\", \"Functional impact of interface dynamics on dephosphorylation not measured\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How RAP74's biochemically defined initiation, elongation, and recycling functions operate and are regulated in living human cells remains unresolved.\",\n      \"evidence\": \"No in vivo loss-of-function or genome-wide functional study appears in the corpus\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No cellular knockdown/knockout phenotype documented\", \"No genome-wide occupancy data in the corpus\", \"No disease association reported\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0, 1, 3]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [6, 10]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [8, 11, 20]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005654\", \"supporting_discovery_ids\": [6, 12]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [12]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [0, 1, 9]}\n    ],\n    \"complexes\": [\"TFIIF (RAP30/RAP74)\", \"RNA polymerase II preinitiation complex\"],\n    \"partners\": [\"GTF2F2\", \"TAF1\", \"FCP1\", \"SRF\", \"CSNK2A1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}