{"gene":"FGFBP1","run_date":"2026-04-28T17:46:03","timeline":{"discoveries":[{"year":2001,"finding":"Purified recombinant FGFBP1 directly binds FGF-2 without additional cofactors, releases FGF-2 from the extracellular matrix, and stimulates tumor cell and endothelial cell proliferation/chemotaxis in a manner fully blocked by anti-FGF-2 antibodies, demonstrating that its paracrine growth-supporting effect is dependent on endogenously expressed FGF-2.","method":"In vitro binding assay with recombinant purified FGF-BP, cell proliferation and chemotaxis assays, antibody neutralization, immunoreactive complex analysis","journal":"International journal of cancer","confidence":"High","confidence_rationale":"Tier 1 — reconstitution with purified proteins plus multiple orthogonal functional assays","pmids":["11304685"],"is_preprint":false},{"year":1998,"finding":"Peptide mapping of FGFBP1 (HBp17) identified residues 110–143 as the principal heparin-binding site, with a basic amino acid cluster contributing to binding to heparin and heparan sulfate proteoglycans of the ECM.","method":"V8 protease and chymotrypsin digestion of purified HBp17 followed by heparin-Sepharose affinity isolation of binding fragments","journal":"Biochemistry and molecular biology international","confidence":"Medium","confidence_rationale":"Tier 1 — in vitro biochemical peptide mapping with purified protein, single study","pmids":["9784842"],"is_preprint":false},{"year":2001,"finding":"Serum induction of FGF-BP transcription requires PKC, MEK/ERK, and p38 MAP kinase activation, and is mediated through C/EBP promoter elements rather than AP-1 or E-box sites, as distinct from EGF-mediated induction.","method":"Promoter deletion analysis, kinase inhibitors, transcription rate assay, serum stimulation of ME-180 cells","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 — promoter analysis with multiple signaling pathway inhibitors in a single study","pmids":["11313920"],"is_preprint":false},{"year":2005,"finding":"Bovine milk FGFBP1 (p37) binds bFGF with higher affinity than lactoferrin, serves as a phosphate acceptor for PKA, CK1, and CK2, and full PKA-mediated phosphorylation abolishes its binding to lactoferrin; sulfatide-induced conformational changes enable CK1 phosphorylation and also reduce lactoferrin binding.","method":"HPLC purification, in vitro kinase assay, FGF binding assay, phosphorylation/binding competition experiments","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 1 — in vitro biochemical characterization with purified protein, single laboratory","pmids":["16412577"],"is_preprint":false},{"year":2001,"finding":"FGFBP1 (HBp17) exerts a biphasic dose-dependent effect on DNA synthesis: stimulatory at low concentrations (~8 ng/ml) and inhibitory at high concentrations (~500 ng/ml); the inhibitory effect is reversed by addition of aFGF or bFGF but not EGF, indicating functional interdependence with FGFs.","method":"DNA synthesis assay in 3T3 cells and HUVECs with recombinant HBp17, FGF rescue experiments","journal":"Cell biology international","confidence":"Medium","confidence_rationale":"Tier 2 — direct cell-based functional assay with recombinant protein and rescue experiments, single study","pmids":["11407864"],"is_preprint":false},{"year":2012,"finding":"1α,25(OH)2D3 down-regulates FGFBP1 (HBp17) expression via the NF-κB pathway: treatment upregulates IκBα, and promoter luciferase assays map the responsive region to -217/+61; VDR siRNA silencing abrogates the effect, confirming VDR dependence.","method":"Luciferase reporter assay, NF-κB pathway analysis (IκBα Western blot), VDR siRNA knockdown","journal":"The Journal of steroid biochemistry and molecular biology","confidence":"Medium","confidence_rationale":"Tier 2 — promoter assay with mechanistic follow-up and siRNA validation, single lab","pmids":["23104116"],"is_preprint":false},{"year":2014,"finding":"1α,25(OH)2D3 suppresses FGFBP1 expression in both nucleus and cytosol of OSCC cells, leading to reduced FGF-2 release into conditioned medium, directly linking FGFBP1 levels to extracellular FGF-2 availability.","method":"Immunofluorescence localization, ELISA measurement of FGF-2 in conditioned medium, 1α,25(OH)2D3 treatment","journal":"In vitro cellular & developmental biology. Animal","confidence":"Medium","confidence_rationale":"Tier 2 — direct localization tied to functional consequence (FGF-2 release), single lab","pmids":["24938357"],"is_preprint":false},{"year":2016,"finding":"miR-146a promotes angiogenesis in endothelial cells via the CREB3L1-FGFBP1 axis: miR-146a directly targets CREB3L1, which normally represses FGFBP1 transcription by binding two CRE-like sites at −1780 and −868 bp relative to the FGFBP1 TSS; loss of CREB3L1 increases FGFBP1 expression and FGF2 secretion.","method":"Luciferase reporter assay, ChIP of CREB3L1 on FGFBP1 promoter, lentiviral miR-146a overexpression, FGF2 ELISA","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 — promoter binding demonstrated by ChIP plus luciferase, functional ELISA readout","pmids":["27121396"],"is_preprint":false},{"year":2017,"finding":"Muscle fiber-secreted FGFBP1 is concentrated at neuromuscular junctions (NMJs); its expression decreases during aging and in SOD1G93A ALS mice before NMJ degeneration. FGFBP1 knockout mice develop structural NMJ abnormalities; knockout in SOD1G93A mice accelerates NMJ degeneration and death. TGF-β1 accumulation in skeletal muscle inhibits FGFBP1 expression.","method":"FGFBP1 knockout mouse model, SOD1G93A double mutant, immunofluorescence localization at NMJs, TGF-β1 treatment","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — genetic loss-of-function with defined structural phenotype, replicated across aging and disease models","pmids":["28053031"],"is_preprint":false},{"year":2017,"finding":"Inducible transgenic expression of FGFBP1 in adult mice elevates mean arterial pressure by >30 mmHg. This hypertensive effect is prevented by angiotensin II receptor antagonist candesartan or ROS inhibitor tempol. FGFBP1 sensitizes peripheral resistance vessels and renal afferent arterioles to AngII constriction ~20-fold via FGF receptor kinase-dependent signaling. In FGF2−/− mice, AngII-mediated arteriolar constriction is abolished but restored by FGF2 plus FGFBP1 add-back. Proteomics identifies downstream MAPK signaling via MKK4, p38, and JNK as integrators of FGFR and AngII crosstalk.","method":"Inducible transgenic mouse model, pharmacological inhibition (candesartan, tempol, FGFR kinase inhibitor), isolated arteriole constriction assay, FGF2−/− mice with protein add-back, kidney proteomics/gene expression","journal":"Hypertension","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal in vivo and ex vivo approaches including KO rescue and pharmacological dissection","pmids":["29158353"],"is_preprint":false},{"year":2020,"finding":"Endothelial-specific ablation of Fgfbp1 in mice delays BBB maturation with upregulation of Plvap and increased tracer leakage, reduces Wnt/β-catenin activity, and decreases collagen IV deposition in the vascular basement membrane, impairing endothelial cell-pericyte interactions. Fgfbp1 acts cell-autonomously in brain endothelial cells to concentrate Wnt ligands near cell junctions.","method":"Conditional endothelial knockout mouse, tracer leakage assay, immunofluorescence, collagen IV staining, in vitro Wnt reporter in mBECs","journal":"Development","confidence":"High","confidence_rationale":"Tier 2 — conditional KO with multiple phenotypic and molecular readouts, mechanistic dissection in vitro","pmids":["32747434"],"is_preprint":false},{"year":2020,"finding":"FGFBP1-mediated signaling sensitizes brain microvessels and macrovessels to AngII constriction after acute kidney injury (AKI); administration of recombinant FGF2 plus FGFBP1 proteins to healthy isolated brain vessels mimics AKI-induced sensitization, and Fgfbp1−/− AKI mice fail to develop this sensitization. FGFR kinase inhibition with BGJ398 reverses the effect.","method":"Bilateral renal ischemia-reperfusion AKI model, Fgfbp1−/− mice, ex vivo vessel constriction assay, recombinant protein add-back, pharmacological FGFR inhibition","journal":"Hypertension","confidence":"High","confidence_rationale":"Tier 2 — KO mouse plus recombinant protein reconstitution and pharmacological dissection","pmids":["33040621"],"is_preprint":false},{"year":2020,"finding":"HSD11B2 promotes colorectal cancer cell migration and invasion by upregulating FGFBP1 expression, which subsequently increases AKT phosphorylation. Knockdown of FGFBP1 or AKT impairs the pro-invasive effect of HSD11B2 overexpression, placing FGFBP1 downstream of HSD11B2 in the HSD11B2-FGFBP1-AKT axis.","method":"mRNA transcriptome array, overexpression and knockdown in CRC cells, in vitro migration/invasion assays, in vivo xenograft, AKT phosphorylation Western blot","journal":"American journal of cancer research","confidence":"Medium","confidence_rationale":"Tier 2 — epistasis established by sequential knockdown with defined pathway readout","pmids":["32195034"],"is_preprint":false},{"year":2021,"finding":"FGFBP1 promotes pancreatic cancer invasion/metastasis through a paracrine mechanism involving cancer-associated fibroblasts (CAFs): FGFBP1 regulates FGF22 secretion from CAFs, and FGF22 signals through FGFR2 on pancreatic cancer cells to facilitate their migration and invasion.","method":"Co-culture of CAFs and pancreatic cancer cells with FGFBP1/FGF22/FGFR2 knockdown, ELISA for FGF22 in conditioned medium, invasion assay","journal":"Acta biochimica et biophysica Sinica","confidence":"Medium","confidence_rationale":"Tier 2 — co-culture epistasis with ELISA validation, single lab","pmids":["34117747"],"is_preprint":false},{"year":2021,"finding":"Poly-L-arginine (mimic of eosinophil MBP) induces FGFBP1 expression in airway epithelial cells via the mTORC1-STAT3 pathway; STAT3 directly binds the FGFBP1 promoter to transactivate it; secreted FGFBP1 acts as a proangiogenic factor, and rapamycin treatment reduces FGFBP1 expression and angiogenesis in OVA-induced asthma mice.","method":"ChIP of STAT3 on FGFBP1 promoter, mTORC1/STAT3 inhibitors, OVA mouse model, rapamycin treatment","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP plus pharmacological pathway dissection in vitro and in vivo, single lab","pmids":["34341336"],"is_preprint":false},{"year":2015,"finding":"FGFBP1 is a direct transcriptional target of Sox12: serial deletion, site-directed mutagenesis, and ChIP assays confirm Sox12 binding to the FGFBP1 promoter. FGFBP1 knockdown decreases Sox12-mediated HCC invasion and metastasis, whereas FGFBP1 overexpression rescues the reduced metastasis caused by Sox12 knockdown.","method":"Serial deletion and mutagenesis of FGFBP1 promoter, ChIP, siRNA knockdown and rescue overexpression, in vitro invasion and in vivo metastasis assays","journal":"Hepatology","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP with mutagenesis plus functional epistasis rescue, single lab","pmids":["25704764"],"is_preprint":false},{"year":2023,"finding":"SGCE interacts with the Sp1 transcription factor and translocates to the nucleus, increasing FGF-BP1 transcription; secreted FGF-BP1 then activates FGF-FGFR signaling to promote cancer cell stemness in triple-negative breast cancer.","method":"Co-immunoprecipitation of SGCE-Sp1, nuclear fractionation, transcriptional reporter assay, FGFBP1 knockdown/overexpression, stem cell assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — reciprocal Co-IP plus transcriptional and functional readouts, single lab","pmids":["37838174"],"is_preprint":false},{"year":2023,"finding":"FGFBP1 acts as an extracellular ligand that rapidly elicits F-actin rearrangement and maintains cobblestone morphology of human keratinocytes independently of FGF interactions. This novel function requires HAI-1; recombinant FGFBP1 at 1 ng/ml reverts morphological and F-actin defects caused by HAI-1 knockout.","method":"HAI-1 KO HaCaT cells, conditioned medium rescue, tandem mass spectrometry identification of FGFBP1, recombinant FGFBP1 add-back, F-actin staining","journal":"Human cell","confidence":"Medium","confidence_rationale":"Tier 2 — protein identification by MS plus recombinant protein functional rescue, single lab","pmids":["37076641"],"is_preprint":false},{"year":2010,"finding":"Morpholino knockdown of fgfbp1 in zebrafish embryos causes massive cell death predominantly in the brain and neural tube and structural abnormalities, indicating an essential role in cellular survival during embryogenesis that can be exerted in an FGF2-independent manner.","method":"Morpholino antisense knockdown in zebrafish, phenotypic analysis of cell death and structural defects","journal":"Molecules and cells","confidence":"Medium","confidence_rationale":"Tier 2 — clean loss-of-function in vertebrate model with defined cellular phenotype","pmids":["20396962"],"is_preprint":false},{"year":2025,"finding":"FGF6 from skeletal muscle regulates FGFBP1 expression through ERK-ATF3 signaling, and FGF6 also perturbs heparin-dependent release kinetics of FGFBP1 by disrupting its liquid-liquid phase separation (LLPS)-driven condensates at the plasma membrane. Circulating FGFBP1 then interacts with hepatic FGF5 via LLPS mechanisms to regulate liver regeneration.","method":"RNA-seq, ATAC-seq, ChIP, luciferase assay, muscle-specific GR/FGF6 knockout mice, FGF6 neutralizing antibody, phase separation assay, ELISA","journal":"Military Medical Research","confidence":"Medium","confidence_rationale":"Tier 1–2 — multiple orthogonal methods in a single study, including phase separation and genetic models","pmids":["40685360"],"is_preprint":false},{"year":2026,"finding":"FGFBP1 is a STAT3-dependent effector of pathological cardiac remodeling: AngII activates STAT3 in cardiomyocytes, which induces FGFBP1 transcription and promotes profibrotic signaling. FGFBP1 KO mice show significantly attenuated cardiac hypertrophy and fibrosis after AngII/TAC, and STAT3 inhibitor S3I-201 reduces FGFBP1 expression and recapitulates the KO phenotype.","method":"FGFBP1 KO mouse model, AngII and TAC cardiac stress models, RNA sequencing, STAT3 pharmacological inhibition, cardiac function and fibrosis assessment","journal":"Biochimica et biophysica acta. Molecular basis of disease","confidence":"High","confidence_rationale":"Tier 2 — KO mouse with two stress models, RNA-seq pathway analysis, and pharmacological validation","pmids":["42013958"],"is_preprint":false},{"year":2026,"finding":"HMGA1 directly binds the FGFBP1 promoter to induce its expression, increasing secretion of FGF2 and promoting tumor progression and angiogenesis in head and neck squamous cell carcinoma via FGFR1 signaling. FGFBP1 silencing or FGFR1 inhibitor PD166866 recapitulates HMGA1 silencing phenotypes.","method":"ChIP of HMGA1 on FGFBP1 promoter, RNA sequencing, FGFBP1 siRNA, FGFR1 inhibitor, xenograft mouse model","journal":"International journal of biological sciences","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP-validated promoter binding with functional epistasis in vitro and in vivo, single lab","pmids":["41943828"],"is_preprint":false},{"year":2025,"finding":"FGFBP1 promotes TNBC cell proliferation, migration, and invasion through the KLK10-AKT axis: FGFBP1 overexpression upregulates KLK10 expression, activating AKT; KLK10 knockdown or AKT inhibition impairs the pro-tumorigenic effects of FGFBP1 overexpression.","method":"Overexpression and knockdown in TNBC cell lines, in vivo xenograft, Western blot for KLK10/AKT, rescue epistasis experiments","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — epistasis established by sequential knockdown with pathway readout, in vivo validation","pmids":["40233428"],"is_preprint":false}],"current_model":"FGFBP1 is a secreted extracellular chaperone that binds FGF-1 and FGF-2 (via a heparin-binding domain at residues 110–143) and mobilizes these FGFs from heparan sulfate proteoglycan stores in the ECM, thereby amplifying paracrine FGF-FGFR signaling to drive cell proliferation, angiogenesis, vascular tone regulation (via sensitization of resistance vessels to AngII through FGFR-MAPK crosstalk), neuromuscular junction maintenance, blood-brain barrier maturation through Wnt/β-catenin activity and collagen IV deposition, and pathological cardiac remodeling downstream of STAT3; its transcription is regulated by multiple upstream factors including STAT3, Sp1, Sox12, HMGA1, KLF5, C/EBP, NF-κB, and mTORC1-STAT3 signaling."},"narrative":{"teleology":[{"year":1998,"claim":"Mapping the heparin-binding domain to residues 110–143 established the structural basis for FGFBP1's interaction with heparan sulfate proteoglycans and, by extension, its capacity to contact ECM-sequestered FGFs.","evidence":"Protease digestion of purified HBp17 followed by heparin-Sepharose affinity isolation of fragments","pmids":["9784842"],"confidence":"Medium","gaps":["Single peptide-mapping study; site-directed mutagenesis of individual basic residues not performed","Three-dimensional structure of the heparin-binding domain is unresolved","Affinity constants for heparan sulfate versus heparin not determined"]},{"year":2001,"claim":"Reconstitution with purified proteins demonstrated that FGFBP1 directly binds FGF-2, liberates it from ECM, and drives proliferation/chemotaxis in an FGF-2-dependent manner, establishing its core molecular function as an FGF mobilizer.","evidence":"In vitro binding assay with recombinant proteins, proliferation/chemotaxis assays, anti-FGF-2 antibody neutralization","pmids":["11304685","11407864"],"confidence":"High","gaps":["Whether FGFBP1 mobilizes FGF family members beyond FGF-1 and FGF-2 was not systematically tested","Stoichiometry of the FGFBP1–FGF-2 complex undetermined"]},{"year":2001,"claim":"Identification of C/EBP-dependent transcription downstream of PKC–MEK/ERK–p38 signaling provided the first map of upstream signals controlling FGFBP1 expression, distinguishing serum- from EGF-driven induction.","evidence":"Promoter deletion/luciferase analysis with kinase inhibitors in ME-180 cells","pmids":["11313920"],"confidence":"Medium","gaps":["C/EBP isoform specificity not resolved","In vivo relevance of these promoter elements not tested"]},{"year":2010,"claim":"Morpholino knockdown in zebrafish revealed an essential developmental role for fgfbp1 in neural cell survival that can operate independently of FGF2, broadening the functional scope beyond FGF-2 mobilization.","evidence":"Morpholino antisense knockdown in zebrafish embryos with phenotypic scoring","pmids":["20396962"],"confidence":"Medium","gaps":["Morpholino off-target effects not fully excluded","The FGF2-independent mechanism was not molecularly identified","Mammalian developmental loss-of-function data were not yet available"]},{"year":2012,"claim":"Vitamin D/VDR-mediated repression of FGFBP1 through NF-κB inhibition established a hormonal input that links metabolic status to FGF mobilization and provided a pharmacological lever for FGFBP1 downregulation.","evidence":"Luciferase promoter assay, IκBα Western blot, VDR siRNA in OSCC cells; confirmed by immunofluorescence and FGF-2 ELISA","pmids":["23104116","24938357"],"confidence":"Medium","gaps":["Direct NF-κB subunit binding to the FGFBP1 promoter not shown by ChIP","In vivo relevance of VDR-mediated FGFBP1 repression untested"]},{"year":2015,"claim":"ChIP and mutagenesis confirmed Sox12 as a direct transcriptional activator of FGFBP1, with functional epistasis showing FGFBP1 mediates Sox12-driven HCC metastasis, expanding the roster of upstream regulators.","evidence":"Serial promoter deletion, site-directed mutagenesis, ChIP, siRNA rescue, in vivo metastasis assay","pmids":["25704764"],"confidence":"Medium","gaps":["Sox12-FGFBP1 axis validated only in hepatocellular carcinoma context","Whether Sox12 cooperates with C/EBP or STAT3 at the promoter is unknown"]},{"year":2016,"claim":"Discovery that CREB3L1 directly represses FGFBP1 and is itself silenced by miR-146a introduced a microRNA–transcription factor relay controlling FGFBP1-dependent angiogenesis.","evidence":"ChIP of CREB3L1 on FGFBP1 promoter CRE-like sites, lentiviral miR-146a overexpression, FGF2 ELISA in endothelial cells","pmids":["27121396"],"confidence":"Medium","gaps":["Endothelial-specific in vivo validation lacking","Whether other CRE-binding repressors compensate when CREB3L1 is depleted is unknown"]},{"year":2017,"claim":"Genetic loss-of-function in mice demonstrated two distinct physiological roles: FGFBP1 is required for neuromuscular junction integrity (declining with age and in ALS), and its transgenic overexpression raises blood pressure by sensitizing resistance vessels to angiotensin II through FGFR–MAPK crosstalk.","evidence":"FGFBP1 KO and inducible transgenic mice; SOD1G93A double mutants; isolated arteriole constriction with pharmacological dissection and FGF2 KO rescue","pmids":["28053031","29158353"],"confidence":"High","gaps":["Molecular intermediates linking FGFR activation to AngII receptor sensitization at the single-cell level not defined","TGF-β1-mediated suppression of FGFBP1 at the NMJ lacks promoter-level mechanism"]},{"year":2020,"claim":"Endothelial-specific KO showed FGFBP1 cell-autonomously concentrates Wnt ligands to drive β-catenin activity and collagen IV deposition during blood–brain barrier maturation, revealing a function beyond classical FGF mobilization.","evidence":"Conditional endothelial KO mouse, tracer leakage, Plvap upregulation, Wnt reporter in brain endothelial cells","pmids":["32747434"],"confidence":"High","gaps":["How FGFBP1 physically concentrates Wnt ligands is unresolved","Whether this Wnt-related role is independent of FGF binding was not fully dissected"]},{"year":2020,"claim":"Multiple studies positioned FGFBP1 as a conduit linking upstream oncogenic signals (HSD11B2, AKT) and vascular stress (AKI) to FGF-dependent pathological responses, reinforcing its role as a signaling amplifier across organ systems.","evidence":"AKI model in FGFBP1 KO mice with protein add-back; HSD11B2-FGFBP1-AKT epistasis in CRC cells","pmids":["33040621","32195034"],"confidence":"High","gaps":["AKI-to-FGFBP1 induction mechanism in kidney not identified","Direct physical interaction between FGFBP1 and AKT pathway components not demonstrated"]},{"year":2021,"claim":"ChIP validated STAT3 as a direct activator of the FGFBP1 promoter downstream of mTORC1, linking eosinophilic inflammation to FGFBP1-dependent angiogenesis in asthma; separately, FGFBP1 was shown to regulate paracrine FGF22–FGFR2 signaling between CAFs and pancreatic cancer cells.","evidence":"ChIP of STAT3 on FGFBP1 promoter, rapamycin in OVA asthma model; CAF-cancer cell co-culture with FGFBP1/FGF22/FGFR2 knockdown","pmids":["34341336","34117747"],"confidence":"Medium","gaps":["Whether STAT3 and C/EBP co-occupy the promoter simultaneously is unknown","FGF22 mobilization by FGFBP1 not confirmed with purified protein binding assays"]},{"year":2023,"claim":"An FGF-independent function was uncovered: FGFBP1 regulates F-actin organization and cobblestone morphology in keratinocytes through a HAI-1-dependent mechanism, demonstrating activities beyond FGF chaperoning.","evidence":"HAI-1 KO HaCaT cells rescued by 1 ng/ml recombinant FGFBP1; mass spectrometry identification; F-actin staining","pmids":["37076641"],"confidence":"Medium","gaps":["The receptor or membrane partner mediating this FGF-independent actin effect is unidentified","HAI-1 dependence mechanism (protease inhibition vs. direct interaction) not dissected"]},{"year":2025,"claim":"Discovery that FGF6–ERK–ATF3 signaling from muscle regulates FGFBP1 expression, and that FGFBP1 undergoes liquid–liquid phase separation modulated by FGF6 to control its release and subsequent interaction with hepatic FGF5 for liver regeneration, introduced phase separation as a biophysical mechanism governing FGFBP1 function.","evidence":"RNA-seq, ATAC-seq, ChIP, muscle-specific KO mice, FGF6 neutralizing antibody, in vitro phase separation assay","pmids":["40685360"],"confidence":"Medium","gaps":["LLPS-driven condensate formation observed in vitro; in vivo condensate visualization not shown","Structural determinants of FGFBP1 phase separation are unknown","Physiological relevance of FGFBP1–FGF5 interaction for liver regeneration requires independent replication"]},{"year":2026,"claim":"FGFBP1 was established as a STAT3-dependent effector of pathological cardiac remodeling: its genetic ablation attenuated AngII- and TAC-induced hypertrophy and fibrosis, closing a loop from AngII→STAT3→FGFBP1→profibrotic signaling.","evidence":"FGFBP1 KO mice subjected to AngII infusion and TAC, RNA-seq, STAT3 inhibitor S3I-201","pmids":["42013958"],"confidence":"High","gaps":["Downstream effectors of FGFBP1 in cardiomyocytes (which FGF ligands are mobilized) not identified","Whether cardiac FGFBP1 also sensitizes coronary vasculature to AngII is untested"]},{"year":null,"claim":"Key unresolved questions include the structural basis for FGFBP1's selectivity among FGF family members, the molecular mechanism of its FGF-independent functions (Wnt concentration, actin remodeling), and whether its liquid–liquid phase separation behavior operates in vivo to regulate ligand release.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal or cryo-EM structure of FGFBP1 alone or in complex with any ligand","FGF-independent mechanisms lack identified receptors or binding partners","Phase separation as a regulatory mechanism requires in vivo validation"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[0,1,3]},{"term_id":"GO:0044183","term_label":"protein folding chaperone","supporting_discovery_ids":[0,6,9]},{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[0,9,11]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,9,10]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[0,6,9,11,17]},{"term_id":"GO:0031012","term_label":"extracellular matrix","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[19]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,9,10,12,20]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[10,18]},{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[10]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[12,13,15,22]}],"complexes":[],"partners":["FGF2","FGF1","FGF22","FGF5","STAT3","HAI-1","FGFR1","FGFR2"],"other_free_text":[]},"mechanistic_narrative":"FGFBP1 is a secreted extracellular chaperone that mobilizes FGF ligands from heparan sulfate proteoglycan stores in the extracellular matrix, thereby amplifying paracrine FGF–FGFR signaling in contexts ranging from angiogenesis and vascular tone regulation to neuromuscular junction maintenance, blood–brain barrier maturation, and pathological cardiac remodeling. The protein directly binds FGF-2 through a heparin-binding domain (residues 110–143) and releases it from the ECM; its proliferative and chemotactic effects are abolished by anti-FGF-2 neutralization, establishing functional dependence on FGF ligand availability [PMID:11304685, PMID:9784842]. Beyond canonical FGF-2 mobilization, FGFBP1 sensitizes resistance arterioles to angiotensin II constriction via FGFR–MAPK crosstalk, raising systemic blood pressure in transgenic mice [PMID:29158353]; in brain endothelium it cell-autonomously concentrates Wnt ligands to promote β-catenin activity and basement membrane collagen IV deposition during blood–brain barrier maturation [PMID:32747434]; and it is a STAT3-dependent effector of AngII-induced cardiac hypertrophy and fibrosis [PMID:42013958]. FGFBP1 transcription is governed by a convergent set of transcription factors—including STAT3, C/EBP, Sox12, HMGA1, Sp1/SGCE, and CREB3L1—and is modulated by mTORC1, NF-κB, and vitamin D receptor signaling [PMID:34341336, PMID:11313920, PMID:25704764, PMID:41943828]."},"prefetch_data":{"uniprot":{"accession":"Q14512","full_name":"Fibroblast growth factor-binding protein 1","aliases":["17 kDa heparin-binding growth factor-binding protein","17 kDa HBGF-binding protein","HBp17"],"length_aa":234,"mass_kda":26.3,"function":"Acts as a carrier protein that release fibroblast-binding factors (FGFs) from the extracellular matrix (EM) storage and thus enhance the mitogenic activity of FGFs. Enhances FGF2 signaling during tissue repair, angiogenesis and in tumor growth","subcellular_location":"Secreted, extracellular space; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q14512/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FGFBP1","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/FGFBP1","total_profiled":1310},"omim":[{"mim_id":"620879","title":"FIBROBLAST GROWTH FACTOR-BINDING PROTEIN 3; FGFBP3","url":"https://www.omim.org/entry/620879"},{"mim_id":"607737","title":"FIBROBLAST GROWTH FACTOR-BINDING PROTEIN 1; FGFBP1","url":"https://www.omim.org/entry/607737"},{"mim_id":"607713","title":"FIBROBLAST GROWTH FACTOR-BINDING PROTEIN 2; FGFBP2","url":"https://www.omim.org/entry/607713"},{"mim_id":"142461","title":"HEPARAN SULFATE PROTEOGLYCAN OF BASEMENT MEMBRANE; HSPG2","url":"https://www.omim.org/entry/142461"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in 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a direct target of FoxQ1, promotes hepatocellular carcinoma metastasis through up-regulating Twist1 and FGFBP1.","date":"2015","source":"Hepatology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/25704764","citation_count":110,"is_preprint":false},{"pmid":"16324873","id":"PMC_16324873","title":"The fibroblast growth factor-binding protein FGF-BP.","date":"2005","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/16324873","citation_count":77,"is_preprint":false},{"pmid":"11304685","id":"PMC_11304685","title":"An FGF-binding protein (FGF-BP) exerts its biological function by parallel paracrine stimulation of tumor cell and endothelial cell proliferation through FGF-2 release.","date":"2001","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/11304685","citation_count":61,"is_preprint":false},{"pmid":"28053031","id":"PMC_28053031","title":"Muscle Fibers Secrete FGFBP1 to Slow Degeneration of 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sulfatide-induced conformational changes enable CK1 phosphorylation and also reduce lactoferrin binding.\",\n      \"method\": \"HPLC purification, in vitro kinase assay, FGF binding assay, phosphorylation/binding competition experiments\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — in vitro biochemical characterization with purified protein, single laboratory\",\n      \"pmids\": [\"16412577\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"FGFBP1 (HBp17) exerts a biphasic dose-dependent effect on DNA synthesis: stimulatory at low concentrations (~8 ng/ml) and inhibitory at high concentrations (~500 ng/ml); the inhibitory effect is reversed by addition of aFGF or bFGF but not EGF, indicating functional interdependence with FGFs.\",\n      \"method\": \"DNA synthesis assay in 3T3 cells and HUVECs with recombinant HBp17, FGF rescue experiments\",\n      \"journal\": \"Cell biology international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct cell-based functional assay with recombinant protein and rescue experiments, single study\",\n      \"pmids\": [\"11407864\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"1α,25(OH)2D3 down-regulates FGFBP1 (HBp17) expression via the NF-κB pathway: treatment upregulates IκBα, and promoter luciferase assays map the responsive region to -217/+61; VDR siRNA silencing abrogates the effect, confirming VDR dependence.\",\n      \"method\": \"Luciferase reporter assay, NF-κB pathway analysis (IκBα Western blot), VDR siRNA knockdown\",\n      \"journal\": \"The Journal of steroid biochemistry and molecular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — promoter assay with mechanistic follow-up and siRNA validation, single lab\",\n      \"pmids\": [\"23104116\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"1α,25(OH)2D3 suppresses FGFBP1 expression in both nucleus and cytosol of OSCC cells, leading to reduced FGF-2 release into conditioned medium, directly linking FGFBP1 levels to extracellular FGF-2 availability.\",\n      \"method\": \"Immunofluorescence localization, ELISA measurement of FGF-2 in conditioned medium, 1α,25(OH)2D3 treatment\",\n      \"journal\": \"In vitro cellular & developmental biology. Animal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct localization tied to functional consequence (FGF-2 release), single lab\",\n      \"pmids\": [\"24938357\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"miR-146a promotes angiogenesis in endothelial cells via the CREB3L1-FGFBP1 axis: miR-146a directly targets CREB3L1, which normally represses FGFBP1 transcription by binding two CRE-like sites at −1780 and −868 bp relative to the FGFBP1 TSS; loss of CREB3L1 increases FGFBP1 expression and FGF2 secretion.\",\n      \"method\": \"Luciferase reporter assay, ChIP of CREB3L1 on FGFBP1 promoter, lentiviral miR-146a overexpression, FGF2 ELISA\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — promoter binding demonstrated by ChIP plus luciferase, functional ELISA readout\",\n      \"pmids\": [\"27121396\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Muscle fiber-secreted FGFBP1 is concentrated at neuromuscular junctions (NMJs); its expression decreases during aging and in SOD1G93A ALS mice before NMJ degeneration. FGFBP1 knockout mice develop structural NMJ abnormalities; knockout in SOD1G93A mice accelerates NMJ degeneration and death. TGF-β1 accumulation in skeletal muscle inhibits FGFBP1 expression.\",\n      \"method\": \"FGFBP1 knockout mouse model, SOD1G93A double mutant, immunofluorescence localization at NMJs, TGF-β1 treatment\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic loss-of-function with defined structural phenotype, replicated across aging and disease models\",\n      \"pmids\": [\"28053031\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Inducible transgenic expression of FGFBP1 in adult mice elevates mean arterial pressure by >30 mmHg. This hypertensive effect is prevented by angiotensin II receptor antagonist candesartan or ROS inhibitor tempol. FGFBP1 sensitizes peripheral resistance vessels and renal afferent arterioles to AngII constriction ~20-fold via FGF receptor kinase-dependent signaling. In FGF2−/− mice, AngII-mediated arteriolar constriction is abolished but restored by FGF2 plus FGFBP1 add-back. Proteomics identifies downstream MAPK signaling via MKK4, p38, and JNK as integrators of FGFR and AngII crosstalk.\",\n      \"method\": \"Inducible transgenic mouse model, pharmacological inhibition (candesartan, tempol, FGFR kinase inhibitor), isolated arteriole constriction assay, FGF2−/− mice with protein add-back, kidney proteomics/gene expression\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal in vivo and ex vivo approaches including KO rescue and pharmacological dissection\",\n      \"pmids\": [\"29158353\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Endothelial-specific ablation of Fgfbp1 in mice delays BBB maturation with upregulation of Plvap and increased tracer leakage, reduces Wnt/β-catenin activity, and decreases collagen IV deposition in the vascular basement membrane, impairing endothelial cell-pericyte interactions. Fgfbp1 acts cell-autonomously in brain endothelial cells to concentrate Wnt ligands near cell junctions.\",\n      \"method\": \"Conditional endothelial knockout mouse, tracer leakage assay, immunofluorescence, collagen IV staining, in vitro Wnt reporter in mBECs\",\n      \"journal\": \"Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional KO with multiple phenotypic and molecular readouts, mechanistic dissection in vitro\",\n      \"pmids\": [\"32747434\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"FGFBP1-mediated signaling sensitizes brain microvessels and macrovessels to AngII constriction after acute kidney injury (AKI); administration of recombinant FGF2 plus FGFBP1 proteins to healthy isolated brain vessels mimics AKI-induced sensitization, and Fgfbp1−/− AKI mice fail to develop this sensitization. FGFR kinase inhibition with BGJ398 reverses the effect.\",\n      \"method\": \"Bilateral renal ischemia-reperfusion AKI model, Fgfbp1−/− mice, ex vivo vessel constriction assay, recombinant protein add-back, pharmacological FGFR inhibition\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse plus recombinant protein reconstitution and pharmacological dissection\",\n      \"pmids\": [\"33040621\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"HSD11B2 promotes colorectal cancer cell migration and invasion by upregulating FGFBP1 expression, which subsequently increases AKT phosphorylation. Knockdown of FGFBP1 or AKT impairs the pro-invasive effect of HSD11B2 overexpression, placing FGFBP1 downstream of HSD11B2 in the HSD11B2-FGFBP1-AKT axis.\",\n      \"method\": \"mRNA transcriptome array, overexpression and knockdown in CRC cells, in vitro migration/invasion assays, in vivo xenograft, AKT phosphorylation Western blot\",\n      \"journal\": \"American journal of cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — epistasis established by sequential knockdown with defined pathway readout\",\n      \"pmids\": [\"32195034\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"FGFBP1 promotes pancreatic cancer invasion/metastasis through a paracrine mechanism involving cancer-associated fibroblasts (CAFs): FGFBP1 regulates FGF22 secretion from CAFs, and FGF22 signals through FGFR2 on pancreatic cancer cells to facilitate their migration and invasion.\",\n      \"method\": \"Co-culture of CAFs and pancreatic cancer cells with FGFBP1/FGF22/FGFR2 knockdown, ELISA for FGF22 in conditioned medium, invasion assay\",\n      \"journal\": \"Acta biochimica et biophysica Sinica\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — co-culture epistasis with ELISA validation, single lab\",\n      \"pmids\": [\"34117747\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Poly-L-arginine (mimic of eosinophil MBP) induces FGFBP1 expression in airway epithelial cells via the mTORC1-STAT3 pathway; STAT3 directly binds the FGFBP1 promoter to transactivate it; secreted FGFBP1 acts as a proangiogenic factor, and rapamycin treatment reduces FGFBP1 expression and angiogenesis in OVA-induced asthma mice.\",\n      \"method\": \"ChIP of STAT3 on FGFBP1 promoter, mTORC1/STAT3 inhibitors, OVA mouse model, rapamycin treatment\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP plus pharmacological pathway dissection in vitro and in vivo, single lab\",\n      \"pmids\": [\"34341336\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"FGFBP1 is a direct transcriptional target of Sox12: serial deletion, site-directed mutagenesis, and ChIP assays confirm Sox12 binding to the FGFBP1 promoter. FGFBP1 knockdown decreases Sox12-mediated HCC invasion and metastasis, whereas FGFBP1 overexpression rescues the reduced metastasis caused by Sox12 knockdown.\",\n      \"method\": \"Serial deletion and mutagenesis of FGFBP1 promoter, ChIP, siRNA knockdown and rescue overexpression, in vitro invasion and in vivo metastasis assays\",\n      \"journal\": \"Hepatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP with mutagenesis plus functional epistasis rescue, single lab\",\n      \"pmids\": [\"25704764\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SGCE interacts with the Sp1 transcription factor and translocates to the nucleus, increasing FGF-BP1 transcription; secreted FGF-BP1 then activates FGF-FGFR signaling to promote cancer cell stemness in triple-negative breast cancer.\",\n      \"method\": \"Co-immunoprecipitation of SGCE-Sp1, nuclear fractionation, transcriptional reporter assay, FGFBP1 knockdown/overexpression, stem cell assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP plus transcriptional and functional readouts, single lab\",\n      \"pmids\": [\"37838174\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"FGFBP1 acts as an extracellular ligand that rapidly elicits F-actin rearrangement and maintains cobblestone morphology of human keratinocytes independently of FGF interactions. This novel function requires HAI-1; recombinant FGFBP1 at 1 ng/ml reverts morphological and F-actin defects caused by HAI-1 knockout.\",\n      \"method\": \"HAI-1 KO HaCaT cells, conditioned medium rescue, tandem mass spectrometry identification of FGFBP1, recombinant FGFBP1 add-back, F-actin staining\",\n      \"journal\": \"Human cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — protein identification by MS plus recombinant protein functional rescue, single lab\",\n      \"pmids\": [\"37076641\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Morpholino knockdown of fgfbp1 in zebrafish embryos causes massive cell death predominantly in the brain and neural tube and structural abnormalities, indicating an essential role in cellular survival during embryogenesis that can be exerted in an FGF2-independent manner.\",\n      \"method\": \"Morpholino antisense knockdown in zebrafish, phenotypic analysis of cell death and structural defects\",\n      \"journal\": \"Molecules and cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean loss-of-function in vertebrate model with defined cellular phenotype\",\n      \"pmids\": [\"20396962\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"FGF6 from skeletal muscle regulates FGFBP1 expression through ERK-ATF3 signaling, and FGF6 also perturbs heparin-dependent release kinetics of FGFBP1 by disrupting its liquid-liquid phase separation (LLPS)-driven condensates at the plasma membrane. Circulating FGFBP1 then interacts with hepatic FGF5 via LLPS mechanisms to regulate liver regeneration.\",\n      \"method\": \"RNA-seq, ATAC-seq, ChIP, luciferase assay, muscle-specific GR/FGF6 knockout mice, FGF6 neutralizing antibody, phase separation assay, ELISA\",\n      \"journal\": \"Military Medical Research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal methods in a single study, including phase separation and genetic models\",\n      \"pmids\": [\"40685360\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"FGFBP1 is a STAT3-dependent effector of pathological cardiac remodeling: AngII activates STAT3 in cardiomyocytes, which induces FGFBP1 transcription and promotes profibrotic signaling. FGFBP1 KO mice show significantly attenuated cardiac hypertrophy and fibrosis after AngII/TAC, and STAT3 inhibitor S3I-201 reduces FGFBP1 expression and recapitulates the KO phenotype.\",\n      \"method\": \"FGFBP1 KO mouse model, AngII and TAC cardiac stress models, RNA sequencing, STAT3 pharmacological inhibition, cardiac function and fibrosis assessment\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular basis of disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with two stress models, RNA-seq pathway analysis, and pharmacological validation\",\n      \"pmids\": [\"42013958\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"HMGA1 directly binds the FGFBP1 promoter to induce its expression, increasing secretion of FGF2 and promoting tumor progression and angiogenesis in head and neck squamous cell carcinoma via FGFR1 signaling. FGFBP1 silencing or FGFR1 inhibitor PD166866 recapitulates HMGA1 silencing phenotypes.\",\n      \"method\": \"ChIP of HMGA1 on FGFBP1 promoter, RNA sequencing, FGFBP1 siRNA, FGFR1 inhibitor, xenograft mouse model\",\n      \"journal\": \"International journal of biological sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP-validated promoter binding with functional epistasis in vitro and in vivo, single lab\",\n      \"pmids\": [\"41943828\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"FGFBP1 promotes TNBC cell proliferation, migration, and invasion through the KLK10-AKT axis: FGFBP1 overexpression upregulates KLK10 expression, activating AKT; KLK10 knockdown or AKT inhibition impairs the pro-tumorigenic effects of FGFBP1 overexpression.\",\n      \"method\": \"Overexpression and knockdown in TNBC cell lines, in vivo xenograft, Western blot for KLK10/AKT, rescue epistasis experiments\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — epistasis established by sequential knockdown with pathway readout, in vivo validation\",\n      \"pmids\": [\"40233428\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FGFBP1 is a secreted extracellular chaperone that binds FGF-1 and FGF-2 (via a heparin-binding domain at residues 110–143) and mobilizes these FGFs from heparan sulfate proteoglycan stores in the ECM, thereby amplifying paracrine FGF-FGFR signaling to drive cell proliferation, angiogenesis, vascular tone regulation (via sensitization of resistance vessels to AngII through FGFR-MAPK crosstalk), neuromuscular junction maintenance, blood-brain barrier maturation through Wnt/β-catenin activity and collagen IV deposition, and pathological cardiac remodeling downstream of STAT3; its transcription is regulated by multiple upstream factors including STAT3, Sp1, Sox12, HMGA1, KLF5, C/EBP, NF-κB, and mTORC1-STAT3 signaling.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"FGFBP1 is a secreted extracellular chaperone that mobilizes FGF ligands from heparan sulfate proteoglycan stores in the extracellular matrix, thereby amplifying paracrine FGF–FGFR signaling in contexts ranging from angiogenesis and vascular tone regulation to neuromuscular junction maintenance, blood–brain barrier maturation, and pathological cardiac remodeling. The protein directly binds FGF-2 through a heparin-binding domain (residues 110–143) and releases it from the ECM; its proliferative and chemotactic effects are abolished by anti-FGF-2 neutralization, establishing functional dependence on FGF ligand availability [PMID:11304685, PMID:9784842]. Beyond canonical FGF-2 mobilization, FGFBP1 sensitizes resistance arterioles to angiotensin II constriction via FGFR–MAPK crosstalk, raising systemic blood pressure in transgenic mice [PMID:29158353]; in brain endothelium it cell-autonomously concentrates Wnt ligands to promote β-catenin activity and basement membrane collagen IV deposition during blood–brain barrier maturation [PMID:32747434]; and it is a STAT3-dependent effector of AngII-induced cardiac hypertrophy and fibrosis [PMID:42013958]. FGFBP1 transcription is governed by a convergent set of transcription factors—including STAT3, C/EBP, Sox12, HMGA1, Sp1/SGCE, and CREB3L1—and is modulated by mTORC1, NF-κB, and vitamin D receptor signaling [PMID:34341336, PMID:11313920, PMID:25704764, PMID:41943828].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Mapping the heparin-binding domain to residues 110–143 established the structural basis for FGFBP1's interaction with heparan sulfate proteoglycans and, by extension, its capacity to contact ECM-sequestered FGFs.\",\n      \"evidence\": \"Protease digestion of purified HBp17 followed by heparin-Sepharose affinity isolation of fragments\",\n      \"pmids\": [\"9784842\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single peptide-mapping study; site-directed mutagenesis of individual basic residues not performed\", \"Three-dimensional structure of the heparin-binding domain is unresolved\", \"Affinity constants for heparan sulfate versus heparin not determined\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Reconstitution with purified proteins demonstrated that FGFBP1 directly binds FGF-2, liberates it from ECM, and drives proliferation/chemotaxis in an FGF-2-dependent manner, establishing its core molecular function as an FGF mobilizer.\",\n      \"evidence\": \"In vitro binding assay with recombinant proteins, proliferation/chemotaxis assays, anti-FGF-2 antibody neutralization\",\n      \"pmids\": [\"11304685\", \"11407864\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether FGFBP1 mobilizes FGF family members beyond FGF-1 and FGF-2 was not systematically tested\", \"Stoichiometry of the FGFBP1–FGF-2 complex undetermined\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Identification of C/EBP-dependent transcription downstream of PKC–MEK/ERK–p38 signaling provided the first map of upstream signals controlling FGFBP1 expression, distinguishing serum- from EGF-driven induction.\",\n      \"evidence\": \"Promoter deletion/luciferase analysis with kinase inhibitors in ME-180 cells\",\n      \"pmids\": [\"11313920\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"C/EBP isoform specificity not resolved\", \"In vivo relevance of these promoter elements not tested\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Morpholino knockdown in zebrafish revealed an essential developmental role for fgfbp1 in neural cell survival that can operate independently of FGF2, broadening the functional scope beyond FGF-2 mobilization.\",\n      \"evidence\": \"Morpholino antisense knockdown in zebrafish embryos with phenotypic scoring\",\n      \"pmids\": [\"20396962\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Morpholino off-target effects not fully excluded\", \"The FGF2-independent mechanism was not molecularly identified\", \"Mammalian developmental loss-of-function data were not yet available\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Vitamin D/VDR-mediated repression of FGFBP1 through NF-κB inhibition established a hormonal input that links metabolic status to FGF mobilization and provided a pharmacological lever for FGFBP1 downregulation.\",\n      \"evidence\": \"Luciferase promoter assay, IκBα Western blot, VDR siRNA in OSCC cells; confirmed by immunofluorescence and FGF-2 ELISA\",\n      \"pmids\": [\"23104116\", \"24938357\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct NF-κB subunit binding to the FGFBP1 promoter not shown by ChIP\", \"In vivo relevance of VDR-mediated FGFBP1 repression untested\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"ChIP and mutagenesis confirmed Sox12 as a direct transcriptional activator of FGFBP1, with functional epistasis showing FGFBP1 mediates Sox12-driven HCC metastasis, expanding the roster of upstream regulators.\",\n      \"evidence\": \"Serial promoter deletion, site-directed mutagenesis, ChIP, siRNA rescue, in vivo metastasis assay\",\n      \"pmids\": [\"25704764\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Sox12-FGFBP1 axis validated only in hepatocellular carcinoma context\", \"Whether Sox12 cooperates with C/EBP or STAT3 at the promoter is unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Discovery that CREB3L1 directly represses FGFBP1 and is itself silenced by miR-146a introduced a microRNA–transcription factor relay controlling FGFBP1-dependent angiogenesis.\",\n      \"evidence\": \"ChIP of CREB3L1 on FGFBP1 promoter CRE-like sites, lentiviral miR-146a overexpression, FGF2 ELISA in endothelial cells\",\n      \"pmids\": [\"27121396\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endothelial-specific in vivo validation lacking\", \"Whether other CRE-binding repressors compensate when CREB3L1 is depleted is unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Genetic loss-of-function in mice demonstrated two distinct physiological roles: FGFBP1 is required for neuromuscular junction integrity (declining with age and in ALS), and its transgenic overexpression raises blood pressure by sensitizing resistance vessels to angiotensin II through FGFR–MAPK crosstalk.\",\n      \"evidence\": \"FGFBP1 KO and inducible transgenic mice; SOD1G93A double mutants; isolated arteriole constriction with pharmacological dissection and FGF2 KO rescue\",\n      \"pmids\": [\"28053031\", \"29158353\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular intermediates linking FGFR activation to AngII receptor sensitization at the single-cell level not defined\", \"TGF-β1-mediated suppression of FGFBP1 at the NMJ lacks promoter-level mechanism\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Endothelial-specific KO showed FGFBP1 cell-autonomously concentrates Wnt ligands to drive β-catenin activity and collagen IV deposition during blood–brain barrier maturation, revealing a function beyond classical FGF mobilization.\",\n      \"evidence\": \"Conditional endothelial KO mouse, tracer leakage, Plvap upregulation, Wnt reporter in brain endothelial cells\",\n      \"pmids\": [\"32747434\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How FGFBP1 physically concentrates Wnt ligands is unresolved\", \"Whether this Wnt-related role is independent of FGF binding was not fully dissected\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Multiple studies positioned FGFBP1 as a conduit linking upstream oncogenic signals (HSD11B2, AKT) and vascular stress (AKI) to FGF-dependent pathological responses, reinforcing its role as a signaling amplifier across organ systems.\",\n      \"evidence\": \"AKI model in FGFBP1 KO mice with protein add-back; HSD11B2-FGFBP1-AKT epistasis in CRC cells\",\n      \"pmids\": [\"33040621\", \"32195034\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"AKI-to-FGFBP1 induction mechanism in kidney not identified\", \"Direct physical interaction between FGFBP1 and AKT pathway components not demonstrated\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"ChIP validated STAT3 as a direct activator of the FGFBP1 promoter downstream of mTORC1, linking eosinophilic inflammation to FGFBP1-dependent angiogenesis in asthma; separately, FGFBP1 was shown to regulate paracrine FGF22–FGFR2 signaling between CAFs and pancreatic cancer cells.\",\n      \"evidence\": \"ChIP of STAT3 on FGFBP1 promoter, rapamycin in OVA asthma model; CAF-cancer cell co-culture with FGFBP1/FGF22/FGFR2 knockdown\",\n      \"pmids\": [\"34341336\", \"34117747\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether STAT3 and C/EBP co-occupy the promoter simultaneously is unknown\", \"FGF22 mobilization by FGFBP1 not confirmed with purified protein binding assays\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"An FGF-independent function was uncovered: FGFBP1 regulates F-actin organization and cobblestone morphology in keratinocytes through a HAI-1-dependent mechanism, demonstrating activities beyond FGF chaperoning.\",\n      \"evidence\": \"HAI-1 KO HaCaT cells rescued by 1 ng/ml recombinant FGFBP1; mass spectrometry identification; F-actin staining\",\n      \"pmids\": [\"37076641\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The receptor or membrane partner mediating this FGF-independent actin effect is unidentified\", \"HAI-1 dependence mechanism (protease inhibition vs. direct interaction) not dissected\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Discovery that FGF6–ERK–ATF3 signaling from muscle regulates FGFBP1 expression, and that FGFBP1 undergoes liquid–liquid phase separation modulated by FGF6 to control its release and subsequent interaction with hepatic FGF5 for liver regeneration, introduced phase separation as a biophysical mechanism governing FGFBP1 function.\",\n      \"evidence\": \"RNA-seq, ATAC-seq, ChIP, muscle-specific KO mice, FGF6 neutralizing antibody, in vitro phase separation assay\",\n      \"pmids\": [\"40685360\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"LLPS-driven condensate formation observed in vitro; in vivo condensate visualization not shown\", \"Structural determinants of FGFBP1 phase separation are unknown\", \"Physiological relevance of FGFBP1–FGF5 interaction for liver regeneration requires independent replication\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"FGFBP1 was established as a STAT3-dependent effector of pathological cardiac remodeling: its genetic ablation attenuated AngII- and TAC-induced hypertrophy and fibrosis, closing a loop from AngII→STAT3→FGFBP1→profibrotic signaling.\",\n      \"evidence\": \"FGFBP1 KO mice subjected to AngII infusion and TAC, RNA-seq, STAT3 inhibitor S3I-201\",\n      \"pmids\": [\"42013958\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream effectors of FGFBP1 in cardiomyocytes (which FGF ligands are mobilized) not identified\", \"Whether cardiac FGFBP1 also sensitizes coronary vasculature to AngII is untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis for FGFBP1's selectivity among FGF family members, the molecular mechanism of its FGF-independent functions (Wnt concentration, actin remodeling), and whether its liquid–liquid phase separation behavior operates in vivo to regulate ligand release.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal or cryo-EM structure of FGFBP1 alone or in complex with any ligand\", \"FGF-independent mechanisms lack identified receptors or binding partners\", \"Phase separation as a regulatory mechanism requires in vivo validation\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [0, 1, 3]},\n      {\"term_id\": \"GO:0044183\", \"supporting_discovery_ids\": [0, 6, 9]},\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 9, 11]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 9, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [0, 6, 9, 11, 17]},\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [19]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 9, 10, 12, 20]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [10, 18]},\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [10]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [12, 13, 15, 22]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"FGF2\",\n      \"FGF1\",\n      \"FGF22\",\n      \"FGF5\",\n      \"STAT3\",\n      \"HAI-1\",\n      \"FGFR1\",\n      \"FGFR2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}