{"gene":"BFAR","run_date":"2026-06-09T22:02:44","timeline":{"discoveries":[{"year":2024,"finding":"BFAR acts as a membrane-bound E3 ubiquitin ligase that promotes ubiquitylation and subsequent proteasomal/autophagic degradation of PNPLA3. BFAR and PNPLA3 co-immunoprecipitate when co-expressed in cells, and BFAR promotes ubiquitylation of PNPLA3 in a reconstituted in vitro assay using purified recombinant proteins. Inactivation of BFAR by siRNA increases PNPLA3 levels in hepatocytes, overexpression decreases them, and Bfar knockout in mice elevates PNPLA3 protein (but not mRNA) on hepatic lipid droplets twofold.","method":"siRNA knockdown in cultured hepatocytes, overexpression in HuH7 cells, co-immunoprecipitation, in vitro ubiquitylation reconstitution assay with purified recombinant proteins, Bfar knockout mouse model with protein/mRNA quantification","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution assay with purified proteins, reciprocal co-IP, KO mouse model, and multiple orthogonal methods in a single rigorous study","pmids":["38294943"],"is_preprint":false},{"year":2025,"finding":"NUV-244, a small molecule identified by high-content screen, reduces PNPLA3 I148M levels via the ubiquitin-proteasome system in a BFAR-dependent manner, confirming BFAR's role as the E3 ligase responsible for PNPLA3 I148M degradation.","method":"High-content compound screen (~820,000 compounds), BFAR-dependent degradation confirmed in liver-derived cells using pharmacological and molecular approaches","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-based screen with BFAR mechanistic confirmation, single lab, partially replicates PNAS 2024 finding","pmids":["40322074"],"is_preprint":false},{"year":2021,"finding":"BFAR mediates K63-linked ubiquitination of TGFβR1 at lysine 268, which is required to activate TGFβ signaling during Th9 cell differentiation. BFAR deficiency or K268R knock-in mutation suppresses TGFβR1 ubiquitination and Th9 differentiation, and TGFβ-induced downregulation of BFAR limits sustained TGFβ signaling.","method":"Genetic KO (BFAR deficiency), K268R knock-in mutation, ubiquitination assays, Th9 differentiation assays, in vivo tumor models","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — site-directed mutagenesis (K268R knock-in), KO model, ubiquitination assay, multiple orthogonal methods in a single rigorous study","pmids":["33914044"],"is_preprint":false},{"year":2024,"finding":"BFAR suppresses cytokine-induced JAK2 signaling by activating JAK2 deubiquitination in aged CD8+ T cells, thereby limiting downstream STAT1-mediated transcriptional reprogramming toward tissue-resident memory T (TRM) cell generation. Bfar knockout or pharmacological inhibition with iBFAR2 restored JAK2 ubiquitination, STAT1 signaling, and TRM generation.","method":"Bfar knockout mouse model, pharmacological inhibitor (iBFAR2), JAK2 ubiquitination assays, STAT1 signaling readouts, CD8+ T cell adoptive transfer tumor models","journal":"Nature aging","confidence":"High","confidence_rationale":"Tier 2 / Strong — KO model, pharmacological inhibitor, ubiquitination assay, multiple orthogonal methods across in vitro and in vivo settings","pmids":["39592880"],"is_preprint":false},{"year":2025,"finding":"BFAR mediates K48-linked ubiquitination and proteasomal degradation of PRP19 in gastric cancer cells. This leads to stabilization of the oncoprotein YBX1, which transcriptionally upregulates neutrophil-recruiting chemokines CXCL1/CXCL3. S100A8/A9 secreted by infiltrating neutrophils activates NF-κB to induce BFAR expression, creating a feed-forward loop sustaining an immunosuppressive tumor microenvironment.","method":"BFAR knockdown functional studies, ubiquitination assays (K48-linked), multiomics analyses, mechanistic pathway validation in gastric cancer cell lines and preclinical models","journal":"Cancer immunology research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ubiquitination type specified (K48-linked), KD functional studies, multiple pathway readouts, single lab","pmids":["40966304"],"is_preprint":false},{"year":2012,"finding":"BFAR interacts with the p75 neurotrophin receptor (p75NTR) and suppresses its downstream NFκB and JNK signaling pathways. The interaction was identified by membrane yeast two-hybrid screening of a human fetal brain cDNA library, and confirmed by GST pull-down and co-immunoprecipitation. The two proteins co-localize in the cytoplasm. BFAR overexpression in PC-12 and HEK293T cells inhibited NFκB and JNK signaling and increased the proportion of cells in G2/M phase.","method":"Membrane yeast two-hybrid screening, GST pull-down, co-immunoprecipitation, fluorescent subcellular localization, luciferase reporter assay (NFκB/JNK), flow cytometry cell cycle analysis","journal":"Science China. Life sciences","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — reciprocal co-IP and GST pull-down confirm interaction, luciferase assay for signaling, single lab with multiple orthogonal methods","pmids":["22566094"],"is_preprint":false},{"year":2021,"finding":"A BFAR isoform (BFARv3/mouse 3110001I22Rik), which resembles periphilin 1 (PPHLN1) due to Lge1 and serine-rich domains, localizes predominantly to the nucleus and interacts with RNA-processing and paraspeckle components NONO and SFPQ (as well as 40S ribosomal proteins and histones). Both the Lge1 and serine-rich domains of BFARv3 are required for binding to NONO and SFPQ. BFARv3 accumulates in nuclear granules upon arsenite treatment or ionizing radiation, and is highly expressed in transcriptionally silent metaphase II oocytes, suggesting a role in RNA metabolism.","method":"Co-immunoprecipitation coupled to mass spectrometry, domain-deletion mutant co-IP, proximity ligation assay, fluorescence microscopy/subcellular localization, EGFP-fusion protein imaging","journal":"Biochimica et biophysica acta. Molecular cell research","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — co-IP/MS plus PLA and domain mutants confirm interaction and localization, but BFARv3 has no human ortholog so relevance to canonical human BFAR is limited; single lab","pmids":["34175335"],"is_preprint":false},{"year":2023,"finding":"BFAR directly binds bufalin (identified by human proteome microarray) and promotes gastric cancer cell proliferation and migration through activation of the PI3K/AKT/mTOR signaling pathway. BFAR knockdown suppressed this pathway and tumor growth/metastasis in vitro and in vivo; bufalin reversed BFAR-driven effects by downregulating BFAR expression.","method":"Human proteome microarray (21,838 proteins) for direct interaction screening, molecular docking, CCK-8, scratch wound healing, transwell assays, Western blotting, in vivo xenograft mouse model","journal":"Apoptosis : an international journal on programmed cell death","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — proteome microarray binding plus functional knockdown with in vivo validation, single lab, PI3K/AKT/mTOR pathway mechanistically supported but detailed ubiquitin mechanism not shown","pmids":["37253905"],"is_preprint":false}],"current_model":"BFAR is a membrane-bound RING-domain E3 ubiquitin ligase that promotes degradation of substrates including PNPLA3 (via ubiquitylation and proteasomal/autophagic turnover) and PRP19 (via K48-linked ubiquitination), activates TGFβ signaling by mediating K63-linked ubiquitination of TGFβR1 at K268 to promote Th9 cell differentiation, and suppresses JAK2 signaling in aged CD8+ T cells by promoting JAK2 deubiquitination, thereby restraining STAT1-dependent tissue-resident memory T cell generation; BFAR also interacts with and suppresses p75NTR-mediated NFκB and JNK signaling, and a mouse-specific nuclear isoform (BFARv3) binds paraspeckle components NONO/SFPQ and participates in RNA metabolism in oocytes."},"narrative":{"mechanistic_narrative":"BFAR is a membrane-associated RING-domain E3 ubiquitin ligase that shapes protein turnover and signaling output in metabolic, immune, and oncogenic contexts by catalyzing substrate-specific ubiquitination [PMID:38294943, PMID:33914044]. In hepatocytes, BFAR directly ubiquitylates PNPLA3 and drives its proteasomal/autophagic degradation: it co-immunoprecipitates with PNPLA3, ubiquitylates it in a reconstituted assay with purified proteins, and its loss elevates PNPLA3 protein on hepatic lipid droplets without changing mRNA [PMID:38294943]; pharmacologic enhancement of this activity selectively reduces the PNPLA3 I148M variant in a BFAR-dependent manner [PMID:40322074]. BFAR diversifies its output through distinct ubiquitin linkages: it adds K63-linked chains to TGFβR1 at Lys268 to activate TGFβ signaling and Th9 cell differentiation [PMID:33914044], whereas it appends K48-linked chains to PRP19 to drive its degradation in gastric cancer, ultimately stabilizing YBX1 and sustaining a neutrophil-driven immunosuppressive microenvironment [PMID:40966304]. Beyond direct ubiquitination, BFAR restrains cytokine-induced JAK2 signaling in aged CD8+ T cells by promoting JAK2 deubiquitination, thereby limiting STAT1-dependent tissue-resident memory T cell generation [PMID:39592880], and it physically interacts with the p75 neurotrophin receptor to suppress downstream NFκB and JNK signaling [PMID:22566094]. BFAR also promotes gastric cancer proliferation and migration via PI3K/AKT/mTOR signaling and is a direct binding target of bufalin [PMID:37253905].","teleology":[{"year":2012,"claim":"Established the first physical partner and signaling role for BFAR, showing it acts as a cytoplasmic suppressor of receptor-driven stress and survival pathways rather than a passive membrane protein.","evidence":"Membrane yeast two-hybrid screen, reciprocal GST pull-down and co-IP, luciferase reporters for NFκB/JNK, and flow cytometry in PC-12 and HEK293T cells","pmids":["22566094"],"confidence":"Medium","gaps":["No ubiquitin-ligase activity was demonstrated in this context","Mechanism by which BFAR suppresses NFκB/JNK downstream of p75NTR not defined","Physiological neuronal relevance not tested in vivo"]},{"year":2021,"claim":"Defined BFAR as a linkage-specific E3 ligase that activates, rather than degrades, a signaling receptor, resolving how it tunes TGFβ-driven T helper differentiation.","evidence":"BFAR knockout and K268R knock-in mice, ubiquitination assays, Th9 differentiation assays, and in vivo tumor models","pmids":["33914044"],"confidence":"High","gaps":["Structural basis for K268 site selectivity not resolved","Whether the same activity operates outside Th9 differentiation untested"]},{"year":2021,"claim":"Identified a nuclear, RNA-associated function for a BFAR isoform, indicating the locus can produce products with roles far from membrane-bound ubiquitination.","evidence":"Co-IP/MS, domain-deletion co-IP, proximity ligation, and fluorescence imaging of EGFP-fusion BFARv3 in cells and oocytes","pmids":["34175335"],"confidence":"Medium","gaps":["BFARv3 is a mouse-specific isoform with no human ortholog, limiting relevance to canonical human BFAR","Functional consequence of NONO/SFPQ binding for RNA metabolism not demonstrated","Role in oocytes inferred from expression, not loss-of-function"]},{"year":2023,"claim":"Linked BFAR to a growth-promoting kinase cascade in cancer and identified it as a direct drug target, expanding its role beyond ubiquitination.","evidence":"Human proteome microarray binding screen, molecular docking, proliferation/migration assays, and xenograft model in gastric cancer","pmids":["37253905"],"confidence":"Medium","gaps":["No ubiquitin-dependent mechanism connecting BFAR to PI3K/AKT/mTOR shown","Direct substrate or signaling intermediate not identified"]},{"year":2024,"claim":"Demonstrated direct, reconstituted E3 ligase activity of BFAR on PNPLA3, establishing it as a bona fide enzyme controlling a lipid-droplet protein in liver.","evidence":"siRNA and overexpression in hepatocytes, reciprocal co-IP, in vitro ubiquitylation with purified recombinant proteins, and Bfar knockout mice with protein/mRNA quantification","pmids":["38294943"],"confidence":"High","gaps":["Ubiquitin chain linkage type on PNPLA3 not specified","Balance between proteasomal versus autophagic routing unresolved"]},{"year":2024,"claim":"Revealed a deubiquitination-promoting activity of BFAR on JAK2, showing it restrains rather than promotes cytokine signaling in aged T cells.","evidence":"Bfar knockout mice, pharmacological inhibitor iBFAR2, JAK2 ubiquitination assays, STAT1 readouts, and CD8+ T cell adoptive transfer tumor models","pmids":["39592880"],"confidence":"High","gaps":["Mechanism by which a RING E3 promotes substrate deubiquitination is not explained","Whether BFAR recruits a DUB or directly opposes ubiquitination unknown"]},{"year":2025,"claim":"Confirmed BFAR is pharmacologically tractable for enhancing degradation of the disease-associated PNPLA3 I148M variant.","evidence":"High-content screen of ~820,000 compounds and BFAR-dependent degradation validation in liver-derived cells (NUV-244)","pmids":["40322074"],"confidence":"Medium","gaps":["Molecular mechanism of compound action on BFAR not resolved","In vivo efficacy not established"]},{"year":2025,"claim":"Extended BFAR's K48-ubiquitination activity to PRP19 in gastric cancer and embedded it in a feed-forward immunosuppressive circuit.","evidence":"BFAR knockdown functional studies, K48-linked ubiquitination assays, multiomics, and preclinical gastric cancer models","pmids":["40966304"],"confidence":"Medium","gaps":["Direct PRP19 ubiquitination by purified BFAR not reconstituted","Generality of the NF-κB/S100A8/A9 feed-forward loop across tumor types untested"]},{"year":null,"claim":"How a single RING-domain E3 selects among opposing outcomes — K63 activation, K48 degradation, and promotion of substrate deubiquitination — and what determines its substrate repertoire across tissues remains unresolved.","evidence":"No structural or systematic substrate-specificity study present in the corpus","pmids":[],"confidence":"Medium","gaps":["No structure of BFAR or its substrate complexes","Determinants of chain-linkage choice unknown","No unified model reconciling ligase and deubiquitination-promoting activities"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,2,4]},{"term_id":"GO:0016874","term_label":"ligase activity","supporting_discovery_ids":[0,2]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[3,5]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[5]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[6]}],"pathway":[],"complexes":[],"partners":["PNPLA3","TGFBR1","PRP19","JAK2","NGFR","NONO","SFPQ"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9NZS9","full_name":"Bifunctional apoptosis regulator","aliases":["RING finger protein 47"],"length_aa":450,"mass_kda":52.7,"function":"Membrane-bound E3 ubiquitin ligase that plays a role in several processes including apoptosis regulation or reticulum endoplasmic stress (PubMed:14502241, PubMed:21068390). Has anti-apoptotic activity, both for apoptosis triggered via death-receptors and via mitochondrial factors (PubMed:14502241). Contributes to the dynamic control of IRE1/ERN1 signaling during ER stress by inducing BAX inhibitor 1/TMBIM6 proteasomal degradation (PubMed:21068390). Promotes the activation of TGF-beta signaling by mediating the 'Lys-63'-linked ubiquitination of TGFBR1 which is critical to activate the pathway (PubMed:33914044). Together with NGFR, negatively regulates NF-kappa-B and JNK-related signaling pathways (PubMed:22566094). Promotes the proteasome-mediated degradation of PNPLA3, a protein involveld in lipid metabolism (PubMed:38294943)","subcellular_location":"Endoplasmic reticulum membrane","url":"https://www.uniprot.org/uniprotkb/Q9NZS9/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/BFAR","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/BFAR","total_profiled":1310},"omim":[{"mim_id":"619516","title":"BIFUNCTIONAL APOPTOSIS REGULATOR; BFAR","url":"https://www.omim.org/entry/619516"},{"mim_id":"610562","title":"ZINC FINGER CCCH DOMAIN-CONTAINING PROTEIN 12A; ZC3H12A","url":"https://www.omim.org/entry/610562"},{"mim_id":"609157","title":"NODAL MODULATOR 1; NOMO1","url":"https://www.omim.org/entry/609157"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/BFAR"},"hgnc":{"alias_symbol":["BAR","RNF47"],"prev_symbol":[]},"alphafold":{"accession":"Q9NZS9","domains":[{"cath_id":"3.30.40.10","chopping":"30-126","consensus_level":"high","plddt":92.3057,"start":30,"end":126},{"cath_id":"1.10.150.50","chopping":"180-250","consensus_level":"high","plddt":91.153,"start":180,"end":250},{"cath_id":"-","chopping":"258-450","consensus_level":"high","plddt":84.1887,"start":258,"end":450}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NZS9","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NZS9-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NZS9-F1-predicted_aligned_error_v6.png","plddt_mean":81.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=BFAR","jax_strain_url":"https://www.jax.org/strain/search?query=BFAR"},"sequence":{"accession":"Q9NZS9","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9NZS9.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9NZS9/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NZS9"}},"corpus_meta":[{"pmid":"15830322","id":"PMC_15830322","title":"Candidate-gene screening and association analysis at the autism-susceptibility locus on chromosome 16p: evidence of association at GRIN2A and ABAT.","date":"2005","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/15830322","citation_count":141,"is_preprint":false},{"pmid":"37253905","id":"PMC_37253905","title":"Bufalin targeting BFAR inhibits the occurrence and metastasis of gastric cancer through PI3K/AKT/mTOR signal pathway.","date":"2023","source":"Apoptosis : an international journal on programmed cell death","url":"https://pubmed.ncbi.nlm.nih.gov/37253905","citation_count":40,"is_preprint":false},{"pmid":"22474427","id":"PMC_22474427","title":"Modulation of apoptosis pathways by oxidative stress and autophagy in β cells.","date":"2012","source":"Experimental diabetes research","url":"https://pubmed.ncbi.nlm.nih.gov/22474427","citation_count":34,"is_preprint":false},{"pmid":"39592880","id":"PMC_39592880","title":"Age-related decline in CD8+ tissue resident memory T cells compromises antitumor immunity.","date":"2024","source":"Nature aging","url":"https://pubmed.ncbi.nlm.nih.gov/39592880","citation_count":32,"is_preprint":false},{"pmid":"33914044","id":"PMC_33914044","title":"BFAR coordinates TGFβ signaling to modulate Th9-mediated cancer immunotherapy.","date":"2021","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/33914044","citation_count":25,"is_preprint":false},{"pmid":"36466608","id":"PMC_36466608","title":"Comprehensive analysis of dysregulated circular RNAs and construction of a ceRNA network involved in the pathology of Alzheimer's disease in a 5 × FAD mouse model.","date":"2022","source":"Frontiers in aging neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/36466608","citation_count":21,"is_preprint":false},{"pmid":"26493719","id":"PMC_26493719","title":"Combined inhibition of Hsp90 and heme oxygenase-1 induces apoptosis and endoplasmic reticulum stress in melanoma.","date":"2015","source":"Acta histochemica","url":"https://pubmed.ncbi.nlm.nih.gov/26493719","citation_count":20,"is_preprint":false},{"pmid":"25008565","id":"PMC_25008565","title":"Altered expression of apoptotic genes in response to OCT4B1 suppression in human tumor cell lines.","date":"2014","source":"Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/25008565","citation_count":19,"is_preprint":false},{"pmid":"26195352","id":"PMC_26195352","title":"Hyperosmotic stress activates the expression of members of the miR-15/107 family and induces downregulation of anti-apoptotic genes in rat liver.","date":"2015","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/26195352","citation_count":18,"is_preprint":false},{"pmid":"38294943","id":"PMC_38294943","title":"The ubiquitin E3 ligase BFAR promotes degradation of PNPLA3.","date":"2024","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/38294943","citation_count":14,"is_preprint":false},{"pmid":"22239233","id":"PMC_22239233","title":"Replication-independent expression of anti-apoptosis marker genes in human peripheral blood mononuclear cells infected with the wild-type HIV-1 and reverse transcriptase variants.","date":"2012","source":"Viral immunology","url":"https://pubmed.ncbi.nlm.nih.gov/22239233","citation_count":6,"is_preprint":false},{"pmid":"28421333","id":"PMC_28421333","title":"Identification of putative second genetic hits in schizophrenia carriers of high-risk copy number variants and resequencing in additional samples.","date":"2017","source":"European archives of psychiatry and clinical neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/28421333","citation_count":6,"is_preprint":false},{"pmid":"22566094","id":"PMC_22566094","title":"p75NTR signal transduction suppressed by BFAR and p75NTR interactions.","date":"2012","source":"Science China. Life sciences","url":"https://pubmed.ncbi.nlm.nih.gov/22566094","citation_count":5,"is_preprint":false},{"pmid":"40867920","id":"PMC_40867920","title":"Role of Endoplasmic Reticulum Stress-Associated Genes in Septic Neonatal Foals.","date":"2025","source":"Antioxidants (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/40867920","citation_count":5,"is_preprint":false},{"pmid":"35559112","id":"PMC_35559112","title":"Proteomics for studying the effects of L. rhamnosus LV108 against non-alcoholic fatty liver disease in rats.","date":"2018","source":"RSC advances","url":"https://pubmed.ncbi.nlm.nih.gov/35559112","citation_count":5,"is_preprint":false},{"pmid":"40322074","id":"PMC_40322074","title":"Identification of NUV-244 as a PNPLA3 I148M degrading small molecule.","date":"2025","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/40322074","citation_count":2,"is_preprint":false},{"pmid":"32524117","id":"PMC_32524117","title":"[Characteristic expression of apoptotic genes in epulis].","date":"2020","source":"Shanghai kou qiang yi xue = Shanghai journal of stomatology","url":"https://pubmed.ncbi.nlm.nih.gov/32524117","citation_count":2,"is_preprint":false},{"pmid":"40966304","id":"PMC_40966304","title":"BFAR Promotes Neutrophil Infiltration and Immunosuppressive Reprogramming through the PRP19-YBX1 Axis to Induce Immune Evasion in Gastric Cancer.","date":"2025","source":"Cancer immunology research","url":"https://pubmed.ncbi.nlm.nih.gov/40966304","citation_count":1,"is_preprint":false},{"pmid":"38370905","id":"PMC_38370905","title":"Detection of Aeromonas hydrophila possessing aerolysin gene using gold nanoparticle probe.","date":"2023","source":"Journal of advanced veterinary and animal research","url":"https://pubmed.ncbi.nlm.nih.gov/38370905","citation_count":1,"is_preprint":false},{"pmid":"34175335","id":"PMC_34175335","title":"The periphilin 1-like BFAR isoform 3 is highly expressed in transcriptionally silent oocytes and involved in RNA metabolism.","date":"2021","source":"Biochimica et biophysica acta. Molecular cell research","url":"https://pubmed.ncbi.nlm.nih.gov/34175335","citation_count":0,"is_preprint":false},{"pmid":"42171433","id":"PMC_42171433","title":"Integrated GC-MS and Network Pharmacology Reveal Component Changes of Atractylodis Rhizoma During Bran-Fried and Anti-Ulcerative Colitis Mechanisms.","date":"2026","source":"Biomedical chromatography : BMC","url":"https://pubmed.ncbi.nlm.nih.gov/42171433","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13148,"output_tokens":2643,"usd":0.039545,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9816,"output_tokens":3260,"usd":0.06529,"stage2_stop_reason":"end_turn"},"total_usd":0.104835,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2024,\n      \"finding\": \"BFAR acts as a membrane-bound E3 ubiquitin ligase that promotes ubiquitylation and subsequent proteasomal/autophagic degradation of PNPLA3. BFAR and PNPLA3 co-immunoprecipitate when co-expressed in cells, and BFAR promotes ubiquitylation of PNPLA3 in a reconstituted in vitro assay using purified recombinant proteins. Inactivation of BFAR by siRNA increases PNPLA3 levels in hepatocytes, overexpression decreases them, and Bfar knockout in mice elevates PNPLA3 protein (but not mRNA) on hepatic lipid droplets twofold.\",\n      \"method\": \"siRNA knockdown in cultured hepatocytes, overexpression in HuH7 cells, co-immunoprecipitation, in vitro ubiquitylation reconstitution assay with purified recombinant proteins, Bfar knockout mouse model with protein/mRNA quantification\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution assay with purified proteins, reciprocal co-IP, KO mouse model, and multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"38294943\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"NUV-244, a small molecule identified by high-content screen, reduces PNPLA3 I148M levels via the ubiquitin-proteasome system in a BFAR-dependent manner, confirming BFAR's role as the E3 ligase responsible for PNPLA3 I148M degradation.\",\n      \"method\": \"High-content compound screen (~820,000 compounds), BFAR-dependent degradation confirmed in liver-derived cells using pharmacological and molecular approaches\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-based screen with BFAR mechanistic confirmation, single lab, partially replicates PNAS 2024 finding\",\n      \"pmids\": [\"40322074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"BFAR mediates K63-linked ubiquitination of TGFβR1 at lysine 268, which is required to activate TGFβ signaling during Th9 cell differentiation. BFAR deficiency or K268R knock-in mutation suppresses TGFβR1 ubiquitination and Th9 differentiation, and TGFβ-induced downregulation of BFAR limits sustained TGFβ signaling.\",\n      \"method\": \"Genetic KO (BFAR deficiency), K268R knock-in mutation, ubiquitination assays, Th9 differentiation assays, in vivo tumor models\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — site-directed mutagenesis (K268R knock-in), KO model, ubiquitination assay, multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"33914044\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"BFAR suppresses cytokine-induced JAK2 signaling by activating JAK2 deubiquitination in aged CD8+ T cells, thereby limiting downstream STAT1-mediated transcriptional reprogramming toward tissue-resident memory T (TRM) cell generation. Bfar knockout or pharmacological inhibition with iBFAR2 restored JAK2 ubiquitination, STAT1 signaling, and TRM generation.\",\n      \"method\": \"Bfar knockout mouse model, pharmacological inhibitor (iBFAR2), JAK2 ubiquitination assays, STAT1 signaling readouts, CD8+ T cell adoptive transfer tumor models\",\n      \"journal\": \"Nature aging\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — KO model, pharmacological inhibitor, ubiquitination assay, multiple orthogonal methods across in vitro and in vivo settings\",\n      \"pmids\": [\"39592880\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"BFAR mediates K48-linked ubiquitination and proteasomal degradation of PRP19 in gastric cancer cells. This leads to stabilization of the oncoprotein YBX1, which transcriptionally upregulates neutrophil-recruiting chemokines CXCL1/CXCL3. S100A8/A9 secreted by infiltrating neutrophils activates NF-κB to induce BFAR expression, creating a feed-forward loop sustaining an immunosuppressive tumor microenvironment.\",\n      \"method\": \"BFAR knockdown functional studies, ubiquitination assays (K48-linked), multiomics analyses, mechanistic pathway validation in gastric cancer cell lines and preclinical models\",\n      \"journal\": \"Cancer immunology research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ubiquitination type specified (K48-linked), KD functional studies, multiple pathway readouts, single lab\",\n      \"pmids\": [\"40966304\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"BFAR interacts with the p75 neurotrophin receptor (p75NTR) and suppresses its downstream NFκB and JNK signaling pathways. The interaction was identified by membrane yeast two-hybrid screening of a human fetal brain cDNA library, and confirmed by GST pull-down and co-immunoprecipitation. The two proteins co-localize in the cytoplasm. BFAR overexpression in PC-12 and HEK293T cells inhibited NFκB and JNK signaling and increased the proportion of cells in G2/M phase.\",\n      \"method\": \"Membrane yeast two-hybrid screening, GST pull-down, co-immunoprecipitation, fluorescent subcellular localization, luciferase reporter assay (NFκB/JNK), flow cytometry cell cycle analysis\",\n      \"journal\": \"Science China. Life sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — reciprocal co-IP and GST pull-down confirm interaction, luciferase assay for signaling, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"22566094\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A BFAR isoform (BFARv3/mouse 3110001I22Rik), which resembles periphilin 1 (PPHLN1) due to Lge1 and serine-rich domains, localizes predominantly to the nucleus and interacts with RNA-processing and paraspeckle components NONO and SFPQ (as well as 40S ribosomal proteins and histones). Both the Lge1 and serine-rich domains of BFARv3 are required for binding to NONO and SFPQ. BFARv3 accumulates in nuclear granules upon arsenite treatment or ionizing radiation, and is highly expressed in transcriptionally silent metaphase II oocytes, suggesting a role in RNA metabolism.\",\n      \"method\": \"Co-immunoprecipitation coupled to mass spectrometry, domain-deletion mutant co-IP, proximity ligation assay, fluorescence microscopy/subcellular localization, EGFP-fusion protein imaging\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — co-IP/MS plus PLA and domain mutants confirm interaction and localization, but BFARv3 has no human ortholog so relevance to canonical human BFAR is limited; single lab\",\n      \"pmids\": [\"34175335\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"BFAR directly binds bufalin (identified by human proteome microarray) and promotes gastric cancer cell proliferation and migration through activation of the PI3K/AKT/mTOR signaling pathway. BFAR knockdown suppressed this pathway and tumor growth/metastasis in vitro and in vivo; bufalin reversed BFAR-driven effects by downregulating BFAR expression.\",\n      \"method\": \"Human proteome microarray (21,838 proteins) for direct interaction screening, molecular docking, CCK-8, scratch wound healing, transwell assays, Western blotting, in vivo xenograft mouse model\",\n      \"journal\": \"Apoptosis : an international journal on programmed cell death\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — proteome microarray binding plus functional knockdown with in vivo validation, single lab, PI3K/AKT/mTOR pathway mechanistically supported but detailed ubiquitin mechanism not shown\",\n      \"pmids\": [\"37253905\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"BFAR is a membrane-bound RING-domain E3 ubiquitin ligase that promotes degradation of substrates including PNPLA3 (via ubiquitylation and proteasomal/autophagic turnover) and PRP19 (via K48-linked ubiquitination), activates TGFβ signaling by mediating K63-linked ubiquitination of TGFβR1 at K268 to promote Th9 cell differentiation, and suppresses JAK2 signaling in aged CD8+ T cells by promoting JAK2 deubiquitination, thereby restraining STAT1-dependent tissue-resident memory T cell generation; BFAR also interacts with and suppresses p75NTR-mediated NFκB and JNK signaling, and a mouse-specific nuclear isoform (BFARv3) binds paraspeckle components NONO/SFPQ and participates in RNA metabolism in oocytes.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"BFAR is a membrane-associated RING-domain E3 ubiquitin ligase that shapes protein turnover and signaling output in metabolic, immune, and oncogenic contexts by catalyzing substrate-specific ubiquitination [#0, #2]. In hepatocytes, BFAR directly ubiquitylates PNPLA3 and drives its proteasomal/autophagic degradation: it co-immunoprecipitates with PNPLA3, ubiquitylates it in a reconstituted assay with purified proteins, and its loss elevates PNPLA3 protein on hepatic lipid droplets without changing mRNA [#0]; pharmacologic enhancement of this activity selectively reduces the PNPLA3 I148M variant in a BFAR-dependent manner [#1]. BFAR diversifies its output through distinct ubiquitin linkages: it adds K63-linked chains to TGFβR1 at Lys268 to activate TGFβ signaling and Th9 cell differentiation [#2], whereas it appends K48-linked chains to PRP19 to drive its degradation in gastric cancer, ultimately stabilizing YBX1 and sustaining a neutrophil-driven immunosuppressive microenvironment [#4]. Beyond direct ubiquitination, BFAR restrains cytokine-induced JAK2 signaling in aged CD8+ T cells by promoting JAK2 deubiquitination, thereby limiting STAT1-dependent tissue-resident memory T cell generation [#3], and it physically interacts with the p75 neurotrophin receptor to suppress downstream NFκB and JNK signaling [#5]. BFAR also promotes gastric cancer proliferation and migration via PI3K/AKT/mTOR signaling and is a direct binding target of bufalin [#7].\",\n  \"teleology\": [\n    {\n      \"year\": 2012,\n      \"claim\": \"Established the first physical partner and signaling role for BFAR, showing it acts as a cytoplasmic suppressor of receptor-driven stress and survival pathways rather than a passive membrane protein.\",\n      \"evidence\": \"Membrane yeast two-hybrid screen, reciprocal GST pull-down and co-IP, luciferase reporters for NFκB/JNK, and flow cytometry in PC-12 and HEK293T cells\",\n      \"pmids\": [\"22566094\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No ubiquitin-ligase activity was demonstrated in this context\", \"Mechanism by which BFAR suppresses NFκB/JNK downstream of p75NTR not defined\", \"Physiological neuronal relevance not tested in vivo\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defined BFAR as a linkage-specific E3 ligase that activates, rather than degrades, a signaling receptor, resolving how it tunes TGFβ-driven T helper differentiation.\",\n      \"evidence\": \"BFAR knockout and K268R knock-in mice, ubiquitination assays, Th9 differentiation assays, and in vivo tumor models\",\n      \"pmids\": [\"33914044\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Structural basis for K268 site selectivity not resolved\", \"Whether the same activity operates outside Th9 differentiation untested\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified a nuclear, RNA-associated function for a BFAR isoform, indicating the locus can produce products with roles far from membrane-bound ubiquitination.\",\n      \"evidence\": \"Co-IP/MS, domain-deletion co-IP, proximity ligation, and fluorescence imaging of EGFP-fusion BFARv3 in cells and oocytes\",\n      \"pmids\": [\"34175335\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"BFARv3 is a mouse-specific isoform with no human ortholog, limiting relevance to canonical human BFAR\", \"Functional consequence of NONO/SFPQ binding for RNA metabolism not demonstrated\", \"Role in oocytes inferred from expression, not loss-of-function\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Linked BFAR to a growth-promoting kinase cascade in cancer and identified it as a direct drug target, expanding its role beyond ubiquitination.\",\n      \"evidence\": \"Human proteome microarray binding screen, molecular docking, proliferation/migration assays, and xenograft model in gastric cancer\",\n      \"pmids\": [\"37253905\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No ubiquitin-dependent mechanism connecting BFAR to PI3K/AKT/mTOR shown\", \"Direct substrate or signaling intermediate not identified\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrated direct, reconstituted E3 ligase activity of BFAR on PNPLA3, establishing it as a bona fide enzyme controlling a lipid-droplet protein in liver.\",\n      \"evidence\": \"siRNA and overexpression in hepatocytes, reciprocal co-IP, in vitro ubiquitylation with purified recombinant proteins, and Bfar knockout mice with protein/mRNA quantification\",\n      \"pmids\": [\"38294943\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Ubiquitin chain linkage type on PNPLA3 not specified\", \"Balance between proteasomal versus autophagic routing unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Revealed a deubiquitination-promoting activity of BFAR on JAK2, showing it restrains rather than promotes cytokine signaling in aged T cells.\",\n      \"evidence\": \"Bfar knockout mice, pharmacological inhibitor iBFAR2, JAK2 ubiquitination assays, STAT1 readouts, and CD8+ T cell adoptive transfer tumor models\",\n      \"pmids\": [\"39592880\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Mechanism by which a RING E3 promotes substrate deubiquitination is not explained\", \"Whether BFAR recruits a DUB or directly opposes ubiquitination unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Confirmed BFAR is pharmacologically tractable for enhancing degradation of the disease-associated PNPLA3 I148M variant.\",\n      \"evidence\": \"High-content screen of ~820,000 compounds and BFAR-dependent degradation validation in liver-derived cells (NUV-244)\",\n      \"pmids\": [\"40322074\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Molecular mechanism of compound action on BFAR not resolved\", \"In vivo efficacy not established\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Extended BFAR's K48-ubiquitination activity to PRP19 in gastric cancer and embedded it in a feed-forward immunosuppressive circuit.\",\n      \"evidence\": \"BFAR knockdown functional studies, K48-linked ubiquitination assays, multiomics, and preclinical gastric cancer models\",\n      \"pmids\": [\"40966304\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Direct PRP19 ubiquitination by purified BFAR not reconstituted\", \"Generality of the NF-κB/S100A8/A9 feed-forward loop across tumor types untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single RING-domain E3 selects among opposing outcomes — K63 activation, K48 degradation, and promotion of substrate deubiquitination — and what determines its substrate repertoire across tissues remains unresolved.\",\n      \"evidence\": \"No structural or systematic substrate-specificity study present in the corpus\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No structure of BFAR or its substrate complexes\", \"Determinants of chain-linkage choice unknown\", \"No unified model reconciling ligase and deubiquitination-promoting activities\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 2, 4]},\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [3, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0000000\", \"supporting_discovery_ids\": []}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"PNPLA3\", \"TGFBR1\", \"PRP19\", \"JAK2\", \"NGFR\", \"NONO\", \"SFPQ\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}