{"gene":"FASLG","run_date":"2026-04-28T17:46:03","timeline":{"discoveries":[{"year":1993,"finding":"FasL (FASLG) was cloned as a type II transmembrane protein belonging to the TNF family, expressed on activated cytotoxic T cells; the recombinant protein induces apoptosis in Fas-expressing target cells, establishing FasL as the functional ligand for Fas-mediated apoptosis.","method":"Expression cloning using soluble Fas-Ig fusion protein to detect FasL on cytotoxic T hybridoma cells; recombinant FasL expressed in COS cells tested on Fas+ targets; Northern hybridization","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 — original cloning with functional reconstitution; foundational paper with 2371 citations","pmids":["7505205"],"is_preprint":false},{"year":1995,"finding":"FasL-Fas interaction mediates activation-induced cell death (AICD) in T-cell hybridomas in a cell-autonomous manner: TCR crosslinking induces both FasL expression and Fas upregulation, and a soluble Fas-Ig fusion protein selectively blocks cell death without affecting activation.","method":"Soluble Fas-immunoglobulin fusion protein blockade; anti-FasL/Fas antibodies; T-cell hybridoma apoptosis assay with TCR crosslinking","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal inhibition experiments; two independent groups (PMID 7530337 and 7530336) with overlapping findings; replicated","pmids":["7530337","7530336"],"is_preprint":false},{"year":1995,"finding":"FasL mediates AICD in previously activated human T lymphocytes: TCR stimulation induces FasL mRNA/cytotoxic activity, and FasL antagonists inhibit AICD in T-cell clones and antigen-specific T-cell lines.","method":"Recombinant human FasL cytolysis assay; FasL antagonist blocking experiments; Fas+ target cell killing assays; RT-PCR for FasL mRNA","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods; replicated across human T-cell systems","pmids":["7528780"],"is_preprint":false},{"year":1995,"finding":"FasL expressed by testicular Sertoli cells establishes immune privilege: normal testis grafts survived allogeneic transplantation indefinitely, whereas testis from gld mice (non-functional FasL) were rejected, demonstrating that FasL induces apoptotic death of activated Fas+ graft-rejecting T cells.","method":"Allogeneic transplantation of testis grafts from wild-type vs. gld mice under kidney capsule; Sertoli cell transplantation experiments","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 — genetic loss-of-function (gld) with clear transplant phenotype; replicated with Sertoli cell transfers","pmids":["7566174"],"is_preprint":false},{"year":1995,"finding":"FasL upregulation by HIV-1 Tat sensitizes T cells to CD95-mediated apoptosis: Tat strongly upregulates CD95L expression, and this mechanism is proposed to contribute to CD4+ T-cell depletion in AIDS.","method":"HIV-1 Tat treatment of T cells; CD95 ligand expression assay; TCR/CD4(gp120)-induced apoptosis with Tat pre-treatment","journal":"Nature","confidence":"Medium","confidence_rationale":"Tier 2 — direct mechanistic experiment with Tat protein and FasL expression measurement; single lab","pmids":["7539892"],"is_preprint":false},{"year":1996,"finding":"Melanoma cells express FasL, which can induce apoptosis in Fas-expressing T cell infiltrates; FasL+ melanoma tumor growth is delayed in Fas-deficient lpr mice, establishing FasL as a mechanism of tumor immune escape ('Fas counterattack').","method":"Immunostaining of metastatic lesions; in vitro apoptosis assay with FasL+ melanoma cells on Fas-sensitive targets; in vivo tumor formation in lpr (Fas-deficient) vs. wild-type mice","journal":"Science","confidence":"High","confidence_rationale":"Tier 1–2 — in vitro functional assay plus in vivo genetic evidence; highly cited foundational paper","pmids":["8910274"],"is_preprint":false},{"year":1998,"finding":"FasL is cleaved by a metalloproteinase to produce soluble FasL; membrane-bound FasL is the functional apoptosis-inducing form, while soluble FasL inhibits cytotoxicity of membrane-bound FasL, indicating that metalloproteinase-mediated shedding downregulates FasL killing activity.","method":"Deletion of cleavage site in human FasL; cytotoxicity assays comparing membrane-bound vs. soluble FasL on Jurkat cells and primary hepatocytes; metalloproteinase inhibitor experiments","journal":"Nature medicine","confidence":"High","confidence_rationale":"Tier 1 — reconstitution with cleavage-site mutant plus functional cytotoxicity comparison; highly cited","pmids":["9427603"],"is_preprint":false},{"year":1998,"finding":"DcR3 (decoy receptor 3) is a soluble TNF receptor family member that binds FasL and inhibits FasL-induced apoptosis; the DcR3 gene is amplified in ~50% of lung and colon tumors, suggesting tumors use DcR3 to escape FasL-dependent immune cytotoxic killing.","method":"Biochemical binding assay of DcR3 with FasL; FasL-induced apoptosis inhibition assay; genomic amplification analysis in primary tumors","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1–2 — binding and functional inhibition assays plus genomic data; highly cited","pmids":["9872321"],"is_preprint":false},{"year":2000,"finding":"FasL binds preassembled trimeric Fas receptor: Fas preassembles into trimers independently of FasL, and this preassembly conditions subsequent FasL binding and death signal transduction.","method":"Biochemical and cellular studies of Fas preassembly (as reviewed/summarized in Perspective citing Chan et al. and Siegel et al.)","journal":"Science","confidence":"Medium","confidence_rationale":"Tier 2 — based on primary experimental findings reviewed; single Perspective paper in corpus","pmids":["10917832"],"is_preprint":false},{"year":2002,"finding":"FasL is present in multivesicular bodies/melanosomes in melanoma cells and is released via FasL-bearing microvesicles that retain functional Fas-mediated apoptosis-inducing activity toward lymphoid cells.","method":"Subcellular fractionation; Western blot and flow cytometry of isolated melanosomes; co-localization of FasL with gp100/CD63; functional apoptosis assay of microvesicles on Jurkat cells","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 1–2 — subcellular fractionation with functional validation; multiple orthogonal methods; highly cited","pmids":["12021310"],"is_preprint":false},{"year":2002,"finding":"The cytosolic polyproline region of FasL (CD178) interacts with SH3 domain proteins Grb2, FBP17, and PACSIN2 via SH3 domain binding; FBP17 and PACSIN2 are implicated in FasL trafficking and surface expression, while Grb2 was previously linked to TCR-to-FasL signaling.","method":"Pulldown from T-cell lysates with FasL cytosolic tail constructs; peptide mass fingerprinting; co-precipitation of overexpressed FasL with FBP17 and PACSIN2; SH3 domain mutation to confirm interaction","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2–3 — Co-IP/pulldown with peptide mass fingerprinting and domain mutagenesis; single lab","pmids":["12023017"],"is_preprint":false},{"year":2006,"finding":"ERK5 promotes cell survival under osmotic stress by downregulating FasL expression via a PKB/Akt-dependent inhibition of Foxo3a transcription factor; loss of ERK5 or MEK5 leads to increased Foxo3a activity and elevated FasL, which acts as a positive feedback loop enhancing apoptosis.","method":"ERK5/MEK5 knockout fibroblasts treated with sorbitol; PKB activity and Foxo3a activity measurement; FasL expression analysis; genetic epistasis with dominant-negative constructs","journal":"Cell death and differentiation","confidence":"Medium","confidence_rationale":"Tier 2 — genetic KO plus epistasis with multiple signaling components; single lab","pmids":["16710360"],"is_preprint":false},{"year":2006,"finding":"The glucocorticoid receptor (GR) represses the human FasL promoter by competing with NFκB for binding to a shared response element at position -990; GR binds this element in vitro and in chromatin, and its occupancy sterically occludes NFκB binding, representing a DNA-binding-dependent mechanism of GR-mediated FasL repression.","method":"FasL promoter deletion and mutagenesis; transient transfection reporter assays; electrophoretic mobility shift assay (EMSA); chromatin immunoprecipitation (ChIP); dominant-negative GR constructs","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 1–2 — promoter mutagenesis, ChIP, and EMSA; single lab, multiple orthogonal methods","pmids":["16770006"],"is_preprint":false},{"year":2009,"finding":"The FasL intracellular polyproline domain interacts with SH3 domains of Tec kinases and sorting nexins, as identified by phage display screening and verified by cellular pulldown assays; these interactions may regulate FasL function, transport, or processing.","method":"Human SH3 domain phage display library screen; pulldown experiments in cellular systems for Tec kinases and sorting nexins","journal":"BMC immunology","confidence":"Medium","confidence_rationale":"Tier 2–3 — phage display followed by cellular pulldown verification; single lab","pmids":["19807924"],"is_preprint":false},{"year":2010,"finding":"FasL palmitoylation within its transmembrane domain is critical for efficient FasL-mediated killing and for FasL processing by ADAM10; FasL processing by ADAM10 occurs preferentially within cholesterol/sphingolipid-rich nanodomains (rafts) where Fas-FasL contact is efficient, and Fas-FasL interaction is required for efficient FasL processing.","method":"Palmitoylation mutants of FasL; ADAM10 processing assay; raft fractionation; FasL-EGFP cleavage reporter; cytotoxicity assays; siRNA knockdown","journal":"Cell death & disease","confidence":"High","confidence_rationale":"Tier 1–2 — mutagenesis of palmitoylation site with functional assays and membrane domain analysis; multiple orthogonal methods","pmids":["21368861"],"is_preprint":false},{"year":2010,"finding":"Antigen-specific cytotoxicity of iNKT cells in vivo depends almost exclusively on the CD95/CD178 (Fas/FasL) pathway, correlates with CD1d expression levels and TCR affinity for glycolipid antigen, and can be used for tumor protection.","method":"In vivo cytotoxicity assay with iNKT cells from spleen, liver, thymus; genetic deficiency experiments (FasL-deficient vs. perforin-deficient mice); flow cytometry; tumor protection assay","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 2 — genetic loss-of-function in vivo with quantitative cytotoxicity readout; replicated across multiple tissue compartments","pmids":["20660713"],"is_preprint":false},{"year":2013,"finding":"ERα signaling in osteoblasts regulates FasL cleavage and solubilization via upregulation of MMP3: 17β-estradiol (E2) activates ERα to increase MMP3 expression, MMP3 then cleaves membrane-bound FasL to release soluble FasL, which induces osteoclast apoptosis.","method":"EGFP-FasL cleavage reporter assay; specific MMP3 inhibitor; MMP3 siRNA knockdown; primary osteoblast cultures from ERαKO mice; conditioned media FasL quantification; osteoclast/osteoblast co-culture apoptosis assay","journal":"Journal of bone and mineral research","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal approaches including genetic KO, siRNA, pharmacologic inhibition, and functional co-culture assays","pmids":["22927007"],"is_preprint":false},{"year":2014,"finding":"Tumor endothelial FasL expression is cooperatively induced by tumor-derived VEGF-A, IL-10, and PGE2, enabling tumor vasculature to kill effector CD8+ T cells while sparing FoxP3+ Treg cells (which are protected by higher c-FLIP expression), establishing a tumor endothelial immune barrier.","method":"Immunostaining of human and mouse tumors; in vitro induction of FasL in endothelial cells by recombinant VEGF-A/IL-10/PGE2; cytotoxicity assays; genetic/pharmacologic FasL suppression in mice with CD8/Foxp3 T cell quantification; c-FLIP expression analysis in Tregs","journal":"Nature medicine","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal in vitro and in vivo approaches; mechanistic pathway validated; highly cited","pmids":["24793239"],"is_preprint":false},{"year":2015,"finding":"Activated platelets express membrane-bound FasL on their surface; platelet-derived membrane-bound FasL induces Fas-dependent apoptosis in neurons, fibroblasts, and neuroblastoma cells; in vivo platelet depletion or platelet-specific FasL deletion (PF4Cre+ FasLfl/fl) reduces tissue apoptosis in stroke and retinal injury models.","method":"Flow cytometry of activated platelets; apoptosis assays with platelet membrane fractions on target cells; FasLΔm/Δm platelet knockout; PF4Cre+ FasLfl/fl conditional knockout mice; stroke model and NMDA retinal injury model","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 — genetic conditional KO with multiple in vivo models and in vitro mechanistic assays","pmids":["26232171"],"is_preprint":false},{"year":2016,"finding":"Crystal structure of FasL in complex with its decoy receptor DcR3 was solved; structural comparison reveals that DcR3 recognizes invariant main-chain and conserved side-chain functionalities to bind multiple TNF ligands; structure-inspired FasL mutations and native glycosylation enhance FasL's ability to induce Jurkat cell apoptosis by reducing aggregation.","method":"X-ray crystallography of FasL:DcR3 complex; mutagenesis of FasL based on structure; Jurkat cell apoptosis assay with glycosylated vs. non-glycosylated FasL variants","journal":"Structure","confidence":"High","confidence_rationale":"Tier 1 — crystal structure with functional mutagenesis validation","pmids":["27806260"],"is_preprint":false},{"year":2018,"finding":"Platelet FasL and RBC FasR (CD95) mediate a direct cell-contact pathway in thrombus formation: platelet activation exposes FasL which activates Fas on RBCs, causing phosphatidylserine externalization on RBCs; genetic deletion of FasL or FasR reduces thrombin generation and thrombus formation in vitro and in vivo.","method":"FasL-/- and FasR-/- mice; in vitro thrombus formation assay; flow cytometry for PS exposure; thrombin generation assay; carotid artery injury and IVC ligation models; surgical specimens from thrombectomy patients","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 — genetic KO studies in multiple in vivo thrombosis models plus in vitro mechanistic assays; multiple orthogonal approaches","pmids":["29952767"],"is_preprint":false},{"year":2018,"finding":"High-dose osteocalcin (GluOC) triggers FasL upregulation on adipocyte plasma membranes via GPRC6A→cAMP→PKA→CREB-p300→FoxO1 signaling cascade; surface FasL then activates Fas on neighboring adipocytes, triggering MLKL phosphorylation/homotrimerization and Ca2+ influx (via TRPM7), generating ROS and inducing necroptosis.","method":"GPRC6A signaling pathway dissection; pharmacological inhibitors of PKA, ERK, SIK2; p300 activation assay; FoxO1/FasL Western blot; MLKL phosphorylation and homotrimerization assay; Ca2+ imaging; mitochondrial fragmentation analysis","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 — systematic pathway dissection with multiple inhibitors in single cellular system; single lab","pmids":["30546087"],"is_preprint":false},{"year":2018,"finding":"TNFα sensitizes hepatocytes to FasL-induced apoptosis through NFκB-mediated transcriptional upregulation and increased surface expression of Fas; genetic deletion, knockdown, or dominant-negative inhibition of NFκB p65 reduces Fas expression and blocks TNFα-induced sensitization, confirmed in vivo by hydrodynamic injection of p65 shRNA.","method":"Primary hepatocytes and cell lines; p65 knockout/siRNA/dominant-negative; Western blot for Fas; hydrodynamic tail-vein injection of p65 shRNA in mice; FasL-induced apoptosis assay","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 — genetic loss-of-function with in vitro and in vivo validation; single lab, multiple orthogonal approaches","pmids":["30185788"],"is_preprint":false},{"year":2021,"finding":"DNA origami nanoagents with nanometer-precise hexagonal FasL arrangements with 10 nm inter-molecular spacing produce the fastest apoptosis kinetics and are 100× more efficient than soluble FasL, demonstrating that hexagonal receptor geometry and specific spacing are critical determinants of FasL-mediated death-inducing signaling complex (DISC) activation.","method":"DNA origami scaffolds with defined FasL arrangements; cell viability and time-to-death kinetics assays; comparison of different geometries (hexagonal, linear, random), spacings, and FasL valencies","journal":"Small","confidence":"High","confidence_rationale":"Tier 1 — reconstitution with precise structural control; multiple geometries and spacings systematically tested","pmids":["34057291"],"is_preprint":false},{"year":1999,"finding":"FasL promoter activation by IL-2 is mediated through SP1 and NFAT binding to a GGGCGGAAA overlapping response element; mutation of the SP1 site (GGGCGG) or NFAT site (GGAAA) each partially reduced IL-2-induced FasL promoter activity, while mutation of both abolished it; the Egr site is not required for IL-2-induced activation.","method":"Transient transfection with FasL promoter deletion/mutation constructs; IL-2-treated peripheral T cells; nuclear expression analysis of SP1, NFAT, Egr-2, Egr-3","journal":"European journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 — promoter mutagenesis with functional reporter assays; single lab","pmids":["10556800"],"is_preprint":false},{"year":2005,"finding":"HIV-1 Nef induces FasL expression and T-cell bystander killing through a p38 MAPK→AP-1 pathway: p38 is required for Nef-induced AP-1 activation; the FasL promoter AP-1 enhancer element is required for Nef-mediated transcriptional activation, and p38 inhibition attenuates HIV-1-mediated bystander CD8 T-cell killing.","method":"Dominant-negative p38 isoforms; p38 siRNA; chemical inhibitors of p38; FasL promoter AP-1 element mutagenesis; reporter assays; HIV-1 bystander CD8 killing assay in vitro","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 — multiple loss-of-function approaches plus promoter mutagenesis; single lab","pmids":["15928037"],"is_preprint":false},{"year":2011,"finding":"TGF-β3 signaling is required for FasL-Fas-caspase extrinsic apoptosis pathway activation during palatogenesis: FasL-Fas-caspase activity is detectable in wild-type palate fusion but absent in Tgf-β3-/- and K14-Cre;Tgfbr2fl/fl mice; FasL-Fas system inhibition causes persistence of the midline epithelial seam, and ectopic FasL rescues apoptosis in Tgfbr2-deficient epithelium.","method":"Tgf-β3 knockout and conditional Tgfbr2 knockout mice; FasL-Fas inhibition in palatal organ culture; ectopic FasL protein application; caspase activity measurement","journal":"Journal of dental research","confidence":"Medium","confidence_rationale":"Tier 2 — genetic epistasis with rescue experiment; multiple genetic models","pmids":["21593251"],"is_preprint":false},{"year":2009,"finding":"FasL synergizes with IFN-γ to activate macrophages to a microbicidal state (enhanced TNF, IL-6, NO secretion and killing of intracellular Leishmania major), while IL-4 suppresses this FasL/IFN-γ synergy, establishing a non-apoptotic signaling function for FasL in macrophage activation.","method":"Bone marrow-derived macrophage stimulation with FasL ± IFN-γ or IL-4; cytokine/NO measurement; intracellular parasite killing assay","journal":"Journal of leukocyte biology","confidence":"Medium","confidence_rationale":"Tier 2 — functional in vitro assay with defined ligands and cytokine readouts; single lab","pmids":["19380712"],"is_preprint":false},{"year":2013,"finding":"In cerebral ischemia/reperfusion, FasL mediates procaspase-3 denitrosylation and activation via the GluR6-FasL-Trx2 pathway: GluR6 antagonism inhibits I/R-induced FasL and Trx2 upregulation; FasL antisense oligodeoxynucleotides and TrxR2 knockdown inhibit procaspase-3 denitrosylation and reduce neuronal apoptosis.","method":"GluR6 antagonist (NS102); FasL antisense oligodeoxynucleotides; TrxR inhibitor (auranofin); TrxR2 antisense; lentiviral FasL/TrxR2 knockdown; S-nitrosylation assay; TUNEL staining; cresyl violet staining in rat hippocampus","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 — multiple loss-of-function approaches in vivo and in vitro; single lab","pmids":["23949220"],"is_preprint":false},{"year":2014,"finding":"D-type cyclins repress FasL and Fas expression in hematopoietic cells; acute shutdown of all three D-cyclins in adult mouse bone marrow upregulates Fas and FasL expression, leading to Fas- and caspase-8-dependent apoptosis of hematopoietic stem and progenitor cells including quiescent HSCs.","method":"Conditional triple D-cyclin knockout in adult bone marrow; Fas/FasL mRNA and protein measurement; caspase-8 activation assay; flow cytometry of HSC populations","journal":"Developmental cell","confidence":"Medium","confidence_rationale":"Tier 2 — genetic loss-of-function with mechanistic downstream pathway validation; single lab","pmids":["25087893"],"is_preprint":false}],"current_model":"FASLG encodes a type II transmembrane TNF-family protein expressed predominantly on activated cytotoxic T and NK cells that induces apoptosis by binding preassembled trimeric Fas/CD95 receptor, recruiting FADD and caspase-8 into a death-inducing signaling complex (DISC); membrane-bound FasL is the functionally active form (soluble FasL generated by metalloproteinase/MMP cleavage is less potent and can inhibit membrane FasL activity), its surface expression and trafficking are regulated by SH3-domain interactions (Grb2, FBP17, PACSIN2, Tec kinases, sorting nexins) with the cytoplasmic polyproline region, palmitoylation within the transmembrane domain controls raft localization and ADAM10 processing, transcription is controlled by NFAT/SP1 (IL-2), AP-1 (Nef/p38), NFκB, and GR, and beyond AICD and cytotoxic T/NK cell killing the protein performs non-apoptotic functions including macrophage activation, platelet-RBC procoagulant signaling, tumor endothelial immune barrier formation, and developmental apoptosis during palatogenesis."},"narrative":{"teleology":[{"year":1993,"claim":"Identification of FasL as the TNF-family ligand for Fas/CD95 resolved the molecular identity of the death-inducing signal on cytotoxic T cells and established the Fas–FasL axis as a major apoptosis pathway.","evidence":"Expression cloning from cytotoxic T hybridoma; recombinant FasL in COS cells induces apoptosis in Fas+ targets","pmids":["7505205"],"confidence":"High","gaps":["Downstream signaling intermediates (FADD, caspase-8 DISC assembly) not yet defined","Regulation of FasL expression unknown at this point"]},{"year":1995,"claim":"Demonstration that FasL mediates T-cell activation-induced cell death (AICD) and maintains immune privilege in testis established its dual role in immune homeostasis and tissue protection.","evidence":"Soluble Fas-Ig blockade prevents AICD in T hybridomas and human T clones; gld (FasL-deficient) testis grafts rejected whereas wild-type grafts survive indefinitely","pmids":["7530337","7530336","7528780","7566174"],"confidence":"High","gaps":["Mechanism by which HIV exploits FasL for CD4 depletion only partially characterized","Relative contribution of FasL vs. perforin in different CTL contexts not resolved"]},{"year":1996,"claim":"Discovery that tumors express FasL to kill infiltrating Fas+ T cells ('Fas counterattack') revealed FasL as a mechanism of tumor immune evasion.","evidence":"FasL+ melanoma cells induce T-cell apoptosis in vitro; tumor growth is delayed in Fas-deficient lpr mice in vivo","pmids":["8910274"],"confidence":"High","gaps":["Generalizability across tumor types debated","Whether tumor FasL expression is sufficient vs. necessary for immune escape not fully dissected"]},{"year":1998,"claim":"Identification of metalloproteinase-mediated FasL cleavage and the DcR3 decoy receptor established two independent mechanisms of FasL activity regulation: proteolytic shedding reduces killing potency, and soluble decoy receptor neutralizes ligand.","evidence":"FasL cleavage-site mutant retains full membrane-bound cytotoxicity; soluble FasL inhibits membrane FasL; DcR3 binds FasL and blocks apoptosis; DcR3 gene amplified in lung/colon tumors","pmids":["9427603","9872321"],"confidence":"High","gaps":["Identity of the specific metalloproteinase(s) responsible in vivo not fully defined at this stage","Physiological contexts where DcR3 dominantly regulates FasL not established"]},{"year":1999,"claim":"Mapping of NFAT and SP1 binding to an overlapping FasL promoter element downstream of IL-2 signaling defined the transcriptional logic for activation-induced FasL expression in T cells.","evidence":"FasL promoter mutagenesis in IL-2-stimulated peripheral T cells; mutation of both SP1 and NFAT sites abolishes IL-2 response","pmids":["10556800"],"confidence":"Medium","gaps":["Chromatin-level regulation and epigenetic control of the FasL locus not addressed","In vivo validation of SP1/NFAT requirement in T-cell AICD not performed"]},{"year":2000,"claim":"Evidence that Fas preassembles into trimers independently of FasL binding reframed the signaling model: FasL engages a pre-formed receptor complex rather than inducing receptor trimerization de novo.","evidence":"Biochemical and cellular Fas preassembly studies reviewed/synthesized","pmids":["10917832"],"confidence":"Medium","gaps":["Stoichiometry of FasL trimer binding to preassembled Fas trimers not resolved","Higher-order clustering requirements for DISC assembly not defined"]},{"year":2002,"claim":"Discovery that FasL traffics through multivesicular bodies and is released on microvesicles, and that SH3-domain proteins FBP17 and PACSIN2 interact with its cytoplasmic polyproline region, established that FasL surface expression and secretion are actively regulated trafficking events.","evidence":"Subcellular fractionation showing FasL in melanosomes/MVBs with functional microvesicle release; pulldown/mass spectrometry identifying FBP17 and PACSIN2 as FasL cytoplasmic tail interactors","pmids":["12021310","12023017"],"confidence":"High","gaps":["Functional consequence of each SH3 interaction on FasL surface delivery not individually dissected","Whether MVB-derived FasL microvesicles operate physiologically in immune killing unclear"]},{"year":2005,"claim":"Mapping of HIV-1 Nef-induced FasL transcription through p38 MAPK→AP-1 defined a viral hijacking mechanism for bystander T-cell killing via the FasL promoter.","evidence":"Dominant-negative p38, siRNA, chemical inhibitors, and FasL promoter AP-1 mutagenesis; HIV-1 bystander CD8 killing assay","pmids":["15928037"],"confidence":"Medium","gaps":["In vivo relevance to HIV-associated CD4/CD8 depletion not directly tested","Relative contribution of Tat vs. Nef pathways to FasL induction in infected cells not resolved"]},{"year":2006,"claim":"Identification of glucocorticoid receptor competition with NFκB at a shared FasL promoter element, and ERK5-PKB-Foxo3a-mediated FasL repression, expanded the transcriptional regulatory network governing FasL expression to include stress and hormonal signaling.","evidence":"GR-NFκB steric occlusion at position -990 by ChIP and EMSA; ERK5/MEK5 KO fibroblasts show elevated Foxo3a-driven FasL","pmids":["16770006","16710360"],"confidence":"Medium","gaps":["Integration of GR, NFκB, Foxo3a, NFAT, and AP-1 inputs at the endogenous locus not modeled","Tissue-specific dominance of individual transcription factors not established"]},{"year":2009,"claim":"Phage display identification of Tec kinases and sorting nexins as additional SH3-domain interactors of FasL's polyproline region broadened the set of candidate trafficking regulators, while demonstration that FasL synergizes with IFN-γ to activate macrophage microbicidal function established a non-apoptotic FasL signaling role.","evidence":"SH3 phage display library screen plus cellular pulldown; bone marrow-derived macrophage stimulation with FasL ± IFN-γ showing enhanced NO and parasite killing","pmids":["19807924","19380712"],"confidence":"Medium","gaps":["Signaling pathway downstream of Fas in macrophage activation not defined","Functional requirement of individual SH3 interactors for FasL trafficking not validated by loss-of-function"]},{"year":2010,"claim":"Demonstration that FasL palmitoylation controls lipid raft localization and ADAM10-mediated processing, and that iNKT cell cytotoxicity depends almost exclusively on FasL, defined critical post-translational and cellular requirements for FasL function.","evidence":"Palmitoylation-site mutants reduce raft association, ADAM10 processing, and killing; FasL-deficient mice show near-complete loss of iNKT cytotoxicity in vivo","pmids":["21368861","20660713"],"confidence":"High","gaps":["Whether palmitoylation is dynamically regulated during immune synapse formation unknown","Role of ADAM10 vs. other metalloproteinases in different cell types not systematically compared"]},{"year":2011,"claim":"Genetic epistasis showing TGF-β3 signaling is required for FasL-Fas-caspase pathway activation during palatal fusion extended FasL's developmental function beyond immune contexts.","evidence":"Tgf-β3 KO and conditional Tgfbr2 KO mice lack palatal FasL-Fas-caspase activity; ectopic FasL rescues apoptosis in Tgfbr2-deficient epithelium","pmids":["21593251"],"confidence":"Medium","gaps":["How TGF-β3 transcriptionally or post-transcriptionally upregulates FasL in palate not defined","Contribution of FasL vs. other apoptotic pathways to normal palatogenesis not quantified"]},{"year":2013,"claim":"Discovery that ERα-induced MMP3 cleaves FasL to generate osteoclast-killing soluble FasL in bone, and that FasL participates in ischemic neuronal apoptosis via GluR6-Trx2-dependent procaspase-3 denitrosylation, revealed tissue-specific non-immune FasL functions.","evidence":"ERα KO osteoblasts, MMP3 inhibitor/siRNA, osteoclast co-culture; FasL antisense, TrxR2 knockdown, S-nitrosylation assays in rat hippocampal ischemia model","pmids":["22927007","23949220"],"confidence":"Medium","gaps":["In vivo skeletal phenotype of FasL-deficient mice with respect to osteoclast apoptosis not fully characterized","Generality of GluR6-FasL-Trx2 pathway beyond hippocampal ischemia unknown"]},{"year":2014,"claim":"Identification of tumor endothelial FasL as a VEGF-A/IL-10/PGE2-driven immune barrier that selectively kills CD8+ T cells while sparing Tregs revealed FasL as a key effector of the immunosuppressive tumor vasculature, and D-cyclin repression of FasL in HSCs linked cell-cycle regulators to Fas-dependent apoptotic control of hematopoietic stem cells.","evidence":"In vitro endothelial FasL induction; genetic/pharmacologic FasL suppression in tumor-bearing mice; conditional triple D-cyclin KO in bone marrow with Fas/FasL/caspase-8 pathway analysis","pmids":["24793239","25087893"],"confidence":"High","gaps":["Whether endothelial FasL barrier is reversible by anti-angiogenic therapy not demonstrated","Mechanism of D-cyclin-mediated FasL transcriptional repression not identified"]},{"year":2016,"claim":"Structural determination of the FasL–DcR3 complex revealed the molecular basis for decoy receptor recognition and enabled structure-guided FasL variants with enhanced apoptotic potency.","evidence":"X-ray crystallography of FasL:DcR3 complex; structure-based FasL mutations and glycosylation enhance Jurkat apoptosis","pmids":["27806260"],"confidence":"High","gaps":["No crystal structure of FasL bound to its cognate receptor Fas/CD95 available","Structural basis for differential signaling between membrane-bound and soluble FasL not resolved"]},{"year":2018,"claim":"Platelet-expressed FasL was shown to drive both tissue apoptosis (neurons, retina) and procoagulant RBC phosphatidylserine exposure for thrombus formation, establishing FasL as a hemostatic and thrombotic effector beyond the immune system.","evidence":"Platelet-specific FasL conditional KO (PF4Cre+ FasLfl/fl); FasL−/− and FasR−/− mice in stroke, retinal injury, and arterial/venous thrombosis models","pmids":["26232171","29952767"],"confidence":"High","gaps":["Whether platelet FasL contributes to pathological thrombosis in human disease not directly tested","Mechanism regulating FasL surface exposure on activated platelets not defined"]},{"year":2021,"claim":"Systematic testing of FasL spatial arrangements on DNA origami established that hexagonal geometry with 10 nm spacing maximizes DISC activation, providing the first nanometer-resolution map of optimal receptor clustering geometry for death signaling.","evidence":"DNA origami nanoagents with defined FasL geometries, spacings, and valencies; apoptosis kinetics in target cells","pmids":["34057291"],"confidence":"High","gaps":["Whether these geometric requirements apply to physiological immune synapse FasL clustering unknown","Structural intermediates of DISC assembly at defined FasL geometries not visualized"]},{"year":null,"claim":"A high-resolution structure of FasL bound to its cognate Fas receptor, the full mechanism by which FasL cytoplasmic SH3 interactions coordinate trafficking to the immune synapse, and the signaling basis for non-apoptotic FasL functions in macrophages and other non-lymphoid cells remain unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No FasL–Fas co-crystal structure available","Individual contributions of SH3 interactors (Grb2, FBP17, PACSIN2, Tec kinases, sorting nexins) to FasL trafficking not resolved by loss-of-function","Signaling pathway downstream of Fas in non-apoptotic macrophage activation not defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[0,1,6,23]},{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[20]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,6,14,18]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[9]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[6,7]}],"pathway":[{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[0,1,2,5,6,23]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[1,2,3,5,15,17]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[11,21,22]},{"term_id":"R-HSA-109582","term_label":"Hemostasis","supporting_discovery_ids":[20]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[26]}],"complexes":[],"partners":["FAS","DCR3","ADAM10","GRB2","FBP17","PACSIN2","MMP3"],"other_free_text":[]},"mechanistic_narrative":"FASLG encodes a type II transmembrane TNF superfamily ligand that triggers apoptosis by engaging preassembled trimeric Fas/CD95 receptors, with membrane-bound FasL being the principal cytotoxic form while metalloproteinase-cleaved soluble FasL is less potent and can antagonize membrane FasL activity [PMID:7505205, PMID:9427603]. In cytotoxic T cells, NK cells, and iNKT cells, FasL mediates target cell killing and activation-induced cell death (AICD), with transcription controlled by NFAT/SP1 (IL-2 signaling), AP-1 (p38 MAPK), NFκB, and glucocorticoid receptor, and surface delivery regulated by SH3-domain interactions of its cytoplasmic polyproline region with Grb2, FBP17, PACSIN2, Tec kinases, and sorting nexins, as well as by palmitoylation-dependent lipid raft localization that governs ADAM10 processing [PMID:7530337, PMID:10556800, PMID:15928037, PMID:16770006, PMID:12023017, PMID:21368861]. Beyond canonical immune cytotoxicity, FasL establishes immune privilege in tissues such as testis, mediates tumor endothelial immune barrier formation through VEGF-A/IL-10/PGE2-induced expression, drives platelet-RBC procoagulant signaling via Fas-dependent phosphatidylserine externalization on erythrocytes, participates in TGF-β3-dependent apoptosis during palatal fusion, and activates macrophages to a microbicidal state in synergy with IFN-γ [PMID:7566174, PMID:24793239, PMID:29952767, PMID:21593251, PMID:19380712]. Hexagonal FasL arrangements at 10 nm spacing on DNA origami scaffolds produce optimal DISC activation, demonstrating that precise receptor clustering geometry is a critical determinant of signaling potency [PMID:34057291]."},"prefetch_data":{"uniprot":{"accession":"P48023","full_name":"Tumor necrosis factor ligand superfamily member 6","aliases":["Apoptosis antigen ligand","APTL","CD95 ligand","CD95-L","Fas antigen ligand","Fas ligand","FasL"],"length_aa":281,"mass_kda":31.5,"function":"Cytokine that binds to TNFRSF6/FAS, a receptor that transduces the apoptotic signal into cells (PubMed:26334989, PubMed:9228058). Involved in cytotoxic T-cell-mediated apoptosis, natural killer cell-mediated apoptosis and in T-cell development (PubMed:7528780, PubMed:9228058, PubMed:9427603). Initiates fratricidal/suicidal activation-induced cell death (AICD) in antigen-activated T-cells contributing to the termination of immune responses (By similarity). TNFRSF6/FAS-mediated apoptosis also has a role in the induction of peripheral tolerance (By similarity). Binds to TNFRSF6B/DcR3, a decoy receptor that blocks apoptosis (PubMed:27806260) Induces FAS-mediated activation of NF-kappa-B, initiating non-apoptotic signaling pathways (By similarity). Can induce apoptosis but does not appear to be essential for this process (PubMed:27806260) Cytoplasmic form induces gene transcription inhibition","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/P48023/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FASLG","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/FASLG","total_profiled":1310},"omim":[{"mim_id":"620293","title":"TMEM9 DOMAIN FAMILY, MEMBER B; TMEM9B","url":"https://www.omim.org/entry/620293"},{"mim_id":"616729","title":"OLFACTORY RECEPTOR, FAMILY 2, SUBFAMILY W, MEMBER 3; OR2W3","url":"https://www.omim.org/entry/616729"},{"mim_id":"301078","title":"IMMUNODEFICIENCY 98 WITH AUTOINFLAMMATION, X-LINKED; IMD98","url":"https://www.omim.org/entry/301078"},{"mim_id":"211980","title":"LUNG CANCER","url":"https://www.omim.org/entry/211980"},{"mim_id":"163730","title":"NITRIC OXIDE SYNTHASE 2; NOS2","url":"https://www.omim.org/entry/163730"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"lymphoid tissue","ntpm":5.3}],"url":"https://www.proteinatlas.org/search/FASLG"},"hgnc":{"alias_symbol":["FasL","CD178"],"prev_symbol":["APT1LG1","TNFSF6"]},"alphafold":{"accession":"P48023","domains":[{"cath_id":"2.60.120.40","chopping":"145-195_211-226_243-279","consensus_level":"high","plddt":96.0808,"start":145,"end":279}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P48023","model_url":"https://alphafold.ebi.ac.uk/files/AF-P48023-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P48023-F1-predicted_aligned_error_v6.png","plddt_mean":80.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FASLG","jax_strain_url":"https://www.jax.org/strain/search?query=FASLG"},"sequence":{"accession":"P48023","fasta_url":"https://rest.uniprot.org/uniprotkb/P48023.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P48023/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P48023"}},"corpus_meta":[{"pmid":"7530337","id":"PMC_7530337","title":"Fas(CD95)/FasL 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activates the apoptotic program. A soluble Fas-immunoglobulin fusion protein selectively prevents cell death but not activation, establishing Fas/FasL as the molecular mechanism of AICD.\",\n      \"method\": \"Soluble Fas-Ig fusion protein blockade, cell death assays in T-cell hybridomas after TCR crosslinking\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — functional reconstitution with dominant-negative decoy receptor, highly replicated foundational study\",\n      \"pmids\": [\"7530337\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"The Fas receptor preassembles into trimers independent of FasL binding, and this preassembly conditions FasL binding and subsequent death signal transduction.\",\n      \"method\": \"Biochemical and structural analysis of Fas preassembly (perspective summarizing Chan et al. and Siegel et al. findings)\",\n      \"journal\": \"Science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — summary of structural/biochemical findings from two independent labs\",\n      \"pmids\": [\"10917832\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The cytosolic polyproline region of FasL (CD178) interacts with Grb2, actin, beta-tubulin, FBP17 (formin binding protein 17), and PACSIN2 via SH3 domain binding, and these interactions are mediated by the polyproline stretch of FasL. FBP17 and PACSIN2 interact with FasL and may regulate its trafficking and surface expression.\",\n      \"method\": \"Pulldown with FasL cytosolic tail constructs from T-cell lysates, peptide mass fingerprinting, co-immunoprecipitation of overexpressed proteins, SH3 domain mutation experiments\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP and domain mutagenesis in single study\",\n      \"pmids\": [\"12023017\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"SH3 domain proteins including Tec kinases and sorting nexins interact with the polyproline-rich intracellular region of FasL, as identified by phage display screening of a human SH3 domain library, with selected interactions verified by cellular pulldown experiments.\",\n      \"method\": \"SH3 domain phage display library screen, cellular pulldown assays\",\n      \"journal\": \"BMC immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — phage display plus cellular pulldown validation for subset of interactions\",\n      \"pmids\": [\"19807924\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"FasL palmitoylation within its transmembrane domain is critical for efficient FasL-mediated killing and for FasL processing by ADAM10. FasL processing by ADAM10 occurs preferentially within cholesterol/sphingolipid-rich nanodomains (lipid rafts), counteracts Fas-mediated cell death, and requires Fas-FasL contact for efficient processing. Sequential processing by ADAM10 (generating APL fragment) and SPPL2a (generating SPA fragment) was defined.\",\n      \"method\": \"Mutagenesis of palmitoylation site, ADAM10 inhibitor treatment, membrane fractionation, cell death assays, fluorescence imaging of raft localization\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — mutagenesis plus inhibitor experiments plus membrane fractionation, multiple orthogonal methods in single study\",\n      \"pmids\": [\"21368861\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Antigen-specific cytotoxicity of invariant NKT (iNKT) cells in vivo depends almost exclusively on the CD95/CD178 (Fas/FasL) pathway, correlates directly with CD1d expression levels on target cells and TCR affinity for the glycolipid antigen, and can be used for tumor protection.\",\n      \"method\": \"In vivo cytotoxicity assays using FasL-deficient mice, CD95/CD178-blocking experiments, tumor protection models\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic loss-of-function in vivo with defined cytotoxic phenotype, multiple antigen conditions tested\",\n      \"pmids\": [\"20660713\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Crystal structure of FasL in complex with its decoy receptor DcR3 was solved, revealing the recognition surface. The structure shows that DcR3 recognizes invariant main-chain and conserved side-chain functionalities of FasL shared across multiple TNF ligands. Native glycosylation or structure-inspired mutations that reduce FasL aggregation significantly enhance its ability to induce Jurkat cell apoptosis, and DcR3 efficiently inhibits this activity.\",\n      \"method\": \"X-ray crystallography, apoptosis assays with recombinant FasL variants, structure-guided mutagenesis\",\n      \"journal\": \"Structure\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure with functional mutagenesis validation\",\n      \"pmids\": [\"27806260\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ERα (estrogen receptor alpha) signaling in osteoblasts regulates MMP3 expression, which cleaves and solubilizes membrane-bound FasL, and the resulting soluble FasL induces osteoclast apoptosis. Knockdown of MMP3 by siRNA or MMP3 inhibitor restores full-length FasL and blocks 17β-estradiol-induced osteoclast apoptosis.\",\n      \"method\": \"EGFP-FasL reporter assays, siRNA knockdown of MMP3, MMP3-specific inhibitors, ERαKO mouse osteoblasts, conditioned media apoptosis assays, Western blotting\",\n      \"journal\": \"Journal of bone and mineral research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods including knockdown, inhibitors, reporter assay, and primary cell validation\",\n      \"pmids\": [\"22927007\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Tumor endothelial FasL expression is cooperatively induced by tumor-derived VEGF-A, IL-10, and PGE2, enabling endothelial cells to kill effector CD8+ T cells while sparing FoxP3+ Tregs (which have higher c-FLIP expression). This creates a selective immune barrier promoting immune tolerance in tumors.\",\n      \"method\": \"FasL-/- mice (genetic suppression), pharmacological VEGF and PGE2 inhibition, in vitro endothelial cytotoxicity assays, c-FLIP expression analysis, tumor T-cell infiltration assays\",\n      \"journal\": \"Nature medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic and pharmacological loss-of-function with mechanistic pathway placement, replicated in human and mouse tumors\",\n      \"pmids\": [\"24793239\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"FADD and Caspase-8 are essential mediators of FasL-induced apoptosis in glioma cells. Some FasL-sensitive glioma cells can be protected by Bcl-2 family members (type II-like), while others cannot (type I-like), demonstrating distinct downstream pathway usage. FasL resistance in some lines is due to downregulation of Caspase-8.\",\n      \"method\": \"FasL treatment of glioma cell line panel, Bcl-2 overexpression, caspase inhibitors, Western blotting for pathway components\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple cell lines with defined molecular pathway components\",\n      \"pmids\": [\"11593384\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ERK5 promotes cell survival by downregulating FasL expression via a PKB-dependent inhibition of Foxo3a downstream of PI3K. In erk5-/- and mek5-/- fibroblasts under osmotic stress, reduced PKB activity leads to increased Foxo3a activity and upregulation of FasL, creating a positive feedback loop enhancing apoptosis.\",\n      \"method\": \"erk5-/- and mek5-/- mouse fibroblasts, sorbitol-induced osmotic stress, PKB activity assays, Foxo3a activity measurement, FasL expression analysis\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with defined pathway epistasis (ERK5→PKB→Foxo3a→FasL) and functional apoptosis readout\",\n      \"pmids\": [\"16710360\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"IL-2-induced FasL gene activation is mediated through SP1 and NFAT binding to an overlapping GGGCGGAAA site in the FasL promoter, but not through Egr-2 or Egr-3. Mutation of either the SP1 (GGGCGG) or NFAT (GGAAA) half-sites reduces IL-2-induced FasL promoter activity, and mutation of both sites causes greater reduction.\",\n      \"method\": \"Transient transfection of FasL promoter deletion and point-mutation constructs, nuclear factor binding assays, transcription factor expression analysis\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — promoter mutagenesis with multiple transcription factor binding sites tested\",\n      \"pmids\": [\"10556800\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"The glucocorticoid receptor (GR) represses FasL promoter activity by competing with NFκB for binding to a shared response element at position -990, representing a DNA binding-dependent mechanism of GR-mediated FasL repression (sterical occlusion of NFκB binding).\",\n      \"method\": \"FasL promoter mutagenesis, in vitro DNA binding assays, chromatin immunoprecipitation, co-transfection with GR and NFκB expression constructs\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro binding plus chromatin-context binding plus functional promoter assays, multiple orthogonal methods\",\n      \"pmids\": [\"16770006\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"HIV-1 Nef induces FasL expression through a p38 MAPK→AP-1 linear signaling pathway. Nef-mediated FasL upregulation and bystander killing of T cells requires p38 activation, and mutation of the AP-1 enhancer element in the FasL promoter abolishes Nef-mediated transcriptional activation.\",\n      \"method\": \"Dominant-negative p38, p38 siRNA, chemical p38 inhibitors, FasL promoter AP-1 site mutagenesis, bystander killing assays\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple loss-of-function approaches (DN, siRNA, inhibitor) plus promoter mutagenesis with functional readout\",\n      \"pmids\": [\"15928037\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Platelet FasL exposure after activation triggers FasR on red blood cells (RBCs), causing RBC phosphatidylserine (PS) externalization, which enhances thrombin generation and thrombus formation. Genetic deletion or inhibition of either FasL or FasR reduces PS exposure, decreases thrombin generation, and protects against arterial thrombosis in vivo.\",\n      \"method\": \"FasL-/- and FasR-/- mice, ferric chloride carotid injury model, IVC ligation model, in vitro platelet-RBC co-incubation assays, PS externalization measurement\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO plus multiple in vivo thrombosis models, orthogonal in vitro confirmation\",\n      \"pmids\": [\"29952767\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Activated platelets present membrane-bound FasL on their surface, and this membrane-bound FasL (but not from resting platelets) induces Fas-mediated apoptosis in neurons, fibroblasts, and neuroblastoma cells. In vivo, platelet-specific FasL deletion (PF4Cre+ FasLfl/fl mice) reduces tissue apoptosis after stroke and retinal NMDA injury. Bax/Bak-mediated mitochondrial signaling is not required but amplifies the response.\",\n      \"method\": \"Platelet-specific FasL conditional KO mice (PF4Cre), isolated membrane fractions, FasLΔm/Δm platelets lacking membrane-bound FasL, stroke model, NMDA retinal model, apoptosis assays\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional genetic KO with specific phenotypic readouts in multiple in vivo models plus membrane fraction mechanistic validation\",\n      \"pmids\": [\"26232171\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"FasL down-regulation on T cells can occur via metalloprotease cleavage or alternatively via endocytosis. Endocytosis inhibitors (cytochalasins, metabolic inhibitors, low temperature) prevent FasL loss, while a metalloprotease inhibitor (KB8301) has no effect in these cells, indicating endocytosis as an alternative mechanism for FasL internalization.\",\n      \"method\": \"Endocytosis inhibitors, metalloprotease inhibitors, flow cytometric measurement of FasL surface levels\",\n      \"journal\": \"Immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — pharmacological inhibitor approach with defined mechanistic readout, single lab\",\n      \"pmids\": [\"11529932\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The FasL-Fas-caspase extrinsic apoptosis pathway functions during palatal fusion and is regulated downstream of TGF-β3/TGFβR2 signaling. Inhibition of FasL-Fas causes persistence of the midline epithelial seam and inhibits caspase activity; ectopic FasL induces apoptosis in palatal epithelium lacking TGFβR2 signaling.\",\n      \"method\": \"Tgf-β3-/- and K14-Cre;Tgfbr2fl/fl mice, FasL-Fas pathway inhibition in palatal organ culture, ectopic FasL protein application, caspase activity assays, TUNEL\",\n      \"journal\": \"Journal of dental research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic models with defined pathway epistasis (TGFβ3→FasL-Fas-caspase), rescue experiment with ectopic FasL\",\n      \"pmids\": [\"21593251\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Hexagonal arrangements of FasL with ~10 nm inter-molecular spacing on DNA origami nanoagents produce the fastest and most efficient apoptosis induction (100× more efficient than soluble FasL), while different spacings, lower FasL numbers, or higher coupling flexibility impair signaling, demonstrating that specific nanoscale FasL geometry dictates DISC activation kinetics.\",\n      \"method\": \"DNA origami scaffolds with precisely positioned FasL, cell death kinetics assays, comparison of different geometric arrangements\",\n      \"journal\": \"Small\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution with precise structural control and quantitative functional readouts, multiple geometric conditions tested\",\n      \"pmids\": [\"34057291\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"A homozygous null FASLG mutation (single-base-pair deletion in exon 1, F87fs×95) causes complete FasL protein deficiency and results in autoimmune lymphoproliferative syndrome (ALPS) with defective reactivation-induced cell death, establishing FasL as essential for this apoptotic pathway in humans.\",\n      \"method\": \"FASLG gene sequencing, Western blot for protein expression, reactivation-induced cell death assay, plasma FasL measurement\",\n      \"journal\": \"The Journal of allergy and clinical immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — human loss-of-function genetics with functional AICD assay validation\",\n      \"pmids\": [\"22857792\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"High-dose osteocalcin (GluOC) activates GPRC6A→cAMP→PKA signaling leading to nuclear PKA entry, inhibition of SIK2, activation of CREB-p300, upregulation of FoxO1, and consequent FasL upregulation at the plasma membrane. FasL then engages Fas on neighboring adipocytes, triggering MLKL phosphorylation/trimerization, Ca2+ influx via TRPM7, ROS generation, and necroptosis.\",\n      \"method\": \"Pharmacological pathway inhibitors, siRNA knockdowns, Western blotting for pathway components (MLKL phosphorylation, DRP1), Ca2+ measurements, mitochondrial fragmentation assays\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple pharmacological and siRNA interventions defining a linear signaling pathway with multiple orthogonal readouts\",\n      \"pmids\": [\"30546087\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"In cerebral ischemia/reperfusion, GluR6 activation induces FasL expression which in turn increases thioredoxin-2 (Trx2) expression, leading to denitrosylation and activation of procaspase-3, causing neuronal apoptosis. Knockdown of FasL or TrxR2 with antisense oligonucleotides or lentiviral shRNA inhibits procaspase-3 denitrosylation and provides neuroprotection.\",\n      \"method\": \"Antisense oligodeoxynucleotides against FasL and TrxR2, lentiviral knockdown, GluR6 antagonist (NS102), auranofin (TrxR inhibitor), S-nitrosylation assays of procaspase-3, TUNEL\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple knockdown approaches with defined pathway (GluR6→FasL→Trx2→procaspase-3 denitrosylation), single lab\",\n      \"pmids\": [\"23949220\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"FasL synergizes with IFN-γ (but not IL-4) to activate macrophages through non-apoptotic Fas signaling, resulting in enhanced TNF, IL-6, and NO secretion and microbicidal killing of intracellular Leishmania major.\",\n      \"method\": \"Bone marrow-derived macrophage cultures with recombinant FasL and cytokines, cytokine secretion assays, NO measurement, intracellular parasite killing assay\",\n      \"journal\": \"Journal of leukocyte biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — in vitro reconstitution with defined stimuli and functional readouts, single lab\",\n      \"pmids\": [\"19380712\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"D-type cyclins (D1, D2, D3) repress the expression of Fas and FasL; acute ablation of all three D-cyclins in adult mouse bone marrow upregulates Fas and FasL and triggers Fas- and caspase-8-dependent apoptosis of hematopoietic stem and progenitor cells.\",\n      \"method\": \"Inducible triple cyclin D knockout in adult mice, caspase-8 inhibition, Fas blocking, flow cytometric apoptosis analysis, gene expression analysis\",\n      \"journal\": \"Developmental cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional genetic ablation in vivo with rescue experiments (Fas blocking, caspase-8 inhibition) confirming pathway mechanism\",\n      \"pmids\": [\"25087893\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"CD4+ T cells mediate graft-versus-myeloid-leukemia effects primarily through FasL and secondarily through perforin, while CD8+ T cells use perforin primarily and FasL minimally, demonstrating distinct cytolytic pathway usage between T-cell subsets for the same leukemia target.\",\n      \"method\": \"Perforin-deficient and FasL-deficient mice in syngeneic GVL model, in vivo tumor challenge, in vitro CTL assays, proliferation assays\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO mice with defined in vivo and in vitro functional readouts distinguishing CD4 vs CD8 pathway usage\",\n      \"pmids\": [\"10910921\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FASLG (FasL/CD178/CD95L) is a TNF superfamily transmembrane protein whose membrane-bound form assembles as a trimer with a functionally critical hexagonal geometry (10 nm inter-molecular spacing) to engage preassembled Fas (CD95) trimers and activate the DISC (FADD→caspase-8→caspase-3) to execute apoptosis; its cytoplasmic polyproline region serves as a docking site for SH3/WW domain proteins (Grb2, FBP17, PACSIN2, Tec kinases, sorting nexins) that regulate intracellular trafficking, lysosomal storage, and surface expression; palmitoylation within its transmembrane domain and localization in lipid rafts control ADAM10-mediated ectodomain shedding to generate immunosuppressive soluble FasL; FasL expression is transcriptionally controlled by SP1/NFAT (IL-2), NFκB (repressed by GR via occlusion), AP-1 (Nef/p38 MAPK), and FoxO1/FoxO3a downstream of PI3K-PKB-ERK5 signaling; physiologically, FasL on activated T and NK cells mediates AICD, cytotoxic killing, and immune privilege; on platelets, membrane-bound FasL drives procoagulant PS externalization on RBCs via FasR; and tumor-derived VEGF-A/IL-10/PGE2 induces endothelial FasL to create a selective T-cell death barrier favoring immune tolerance.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1993,\n      \"finding\": \"FasL (FASLG) was cloned as a type II transmembrane protein belonging to the TNF family, expressed on activated cytotoxic T cells; the recombinant protein induces apoptosis in Fas-expressing target cells, establishing FasL as the functional ligand for Fas-mediated apoptosis.\",\n      \"method\": \"Expression cloning using soluble Fas-Ig fusion protein to detect FasL on cytotoxic T hybridoma cells; recombinant FasL expressed in COS cells tested on Fas+ targets; Northern hybridization\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — original cloning with functional reconstitution; foundational paper with 2371 citations\",\n      \"pmids\": [\"7505205\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"FasL-Fas interaction mediates activation-induced cell death (AICD) in T-cell hybridomas in a cell-autonomous manner: TCR crosslinking induces both FasL expression and Fas upregulation, and a soluble Fas-Ig fusion protein selectively blocks cell death without affecting activation.\",\n      \"method\": \"Soluble Fas-immunoglobulin fusion protein blockade; anti-FasL/Fas antibodies; T-cell hybridoma apoptosis assay with TCR crosslinking\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal inhibition experiments; two independent groups (PMID 7530337 and 7530336) with overlapping findings; replicated\",\n      \"pmids\": [\"7530337\", \"7530336\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"FasL mediates AICD in previously activated human T lymphocytes: TCR stimulation induces FasL mRNA/cytotoxic activity, and FasL antagonists inhibit AICD in T-cell clones and antigen-specific T-cell lines.\",\n      \"method\": \"Recombinant human FasL cytolysis assay; FasL antagonist blocking experiments; Fas+ target cell killing assays; RT-PCR for FasL mRNA\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods; replicated across human T-cell systems\",\n      \"pmids\": [\"7528780\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"FasL expressed by testicular Sertoli cells establishes immune privilege: normal testis grafts survived allogeneic transplantation indefinitely, whereas testis from gld mice (non-functional FasL) were rejected, demonstrating that FasL induces apoptotic death of activated Fas+ graft-rejecting T cells.\",\n      \"method\": \"Allogeneic transplantation of testis grafts from wild-type vs. gld mice under kidney capsule; Sertoli cell transplantation experiments\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic loss-of-function (gld) with clear transplant phenotype; replicated with Sertoli cell transfers\",\n      \"pmids\": [\"7566174\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"FasL upregulation by HIV-1 Tat sensitizes T cells to CD95-mediated apoptosis: Tat strongly upregulates CD95L expression, and this mechanism is proposed to contribute to CD4+ T-cell depletion in AIDS.\",\n      \"method\": \"HIV-1 Tat treatment of T cells; CD95 ligand expression assay; TCR/CD4(gp120)-induced apoptosis with Tat pre-treatment\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct mechanistic experiment with Tat protein and FasL expression measurement; single lab\",\n      \"pmids\": [\"7539892\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Melanoma cells express FasL, which can induce apoptosis in Fas-expressing T cell infiltrates; FasL+ melanoma tumor growth is delayed in Fas-deficient lpr mice, establishing FasL as a mechanism of tumor immune escape ('Fas counterattack').\",\n      \"method\": \"Immunostaining of metastatic lesions; in vitro apoptosis assay with FasL+ melanoma cells on Fas-sensitive targets; in vivo tumor formation in lpr (Fas-deficient) vs. wild-type mice\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — in vitro functional assay plus in vivo genetic evidence; highly cited foundational paper\",\n      \"pmids\": [\"8910274\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"FasL is cleaved by a metalloproteinase to produce soluble FasL; membrane-bound FasL is the functional apoptosis-inducing form, while soluble FasL inhibits cytotoxicity of membrane-bound FasL, indicating that metalloproteinase-mediated shedding downregulates FasL killing activity.\",\n      \"method\": \"Deletion of cleavage site in human FasL; cytotoxicity assays comparing membrane-bound vs. soluble FasL on Jurkat cells and primary hepatocytes; metalloproteinase inhibitor experiments\",\n      \"journal\": \"Nature medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution with cleavage-site mutant plus functional cytotoxicity comparison; highly cited\",\n      \"pmids\": [\"9427603\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"DcR3 (decoy receptor 3) is a soluble TNF receptor family member that binds FasL and inhibits FasL-induced apoptosis; the DcR3 gene is amplified in ~50% of lung and colon tumors, suggesting tumors use DcR3 to escape FasL-dependent immune cytotoxic killing.\",\n      \"method\": \"Biochemical binding assay of DcR3 with FasL; FasL-induced apoptosis inhibition assay; genomic amplification analysis in primary tumors\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — binding and functional inhibition assays plus genomic data; highly cited\",\n      \"pmids\": [\"9872321\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"FasL binds preassembled trimeric Fas receptor: Fas preassembles into trimers independently of FasL, and this preassembly conditions subsequent FasL binding and death signal transduction.\",\n      \"method\": \"Biochemical and cellular studies of Fas preassembly (as reviewed/summarized in Perspective citing Chan et al. and Siegel et al.)\",\n      \"journal\": \"Science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — based on primary experimental findings reviewed; single Perspective paper in corpus\",\n      \"pmids\": [\"10917832\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"FasL is present in multivesicular bodies/melanosomes in melanoma cells and is released via FasL-bearing microvesicles that retain functional Fas-mediated apoptosis-inducing activity toward lymphoid cells.\",\n      \"method\": \"Subcellular fractionation; Western blot and flow cytometry of isolated melanosomes; co-localization of FasL with gp100/CD63; functional apoptosis assay of microvesicles on Jurkat cells\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — subcellular fractionation with functional validation; multiple orthogonal methods; highly cited\",\n      \"pmids\": [\"12021310\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The cytosolic polyproline region of FasL (CD178) interacts with SH3 domain proteins Grb2, FBP17, and PACSIN2 via SH3 domain binding; FBP17 and PACSIN2 are implicated in FasL trafficking and surface expression, while Grb2 was previously linked to TCR-to-FasL signaling.\",\n      \"method\": \"Pulldown from T-cell lysates with FasL cytosolic tail constructs; peptide mass fingerprinting; co-precipitation of overexpressed FasL with FBP17 and PACSIN2; SH3 domain mutation to confirm interaction\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — Co-IP/pulldown with peptide mass fingerprinting and domain mutagenesis; single lab\",\n      \"pmids\": [\"12023017\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"ERK5 promotes cell survival under osmotic stress by downregulating FasL expression via a PKB/Akt-dependent inhibition of Foxo3a transcription factor; loss of ERK5 or MEK5 leads to increased Foxo3a activity and elevated FasL, which acts as a positive feedback loop enhancing apoptosis.\",\n      \"method\": \"ERK5/MEK5 knockout fibroblasts treated with sorbitol; PKB activity and Foxo3a activity measurement; FasL expression analysis; genetic epistasis with dominant-negative constructs\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO plus epistasis with multiple signaling components; single lab\",\n      \"pmids\": [\"16710360\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"The glucocorticoid receptor (GR) represses the human FasL promoter by competing with NFκB for binding to a shared response element at position -990; GR binds this element in vitro and in chromatin, and its occupancy sterically occludes NFκB binding, representing a DNA-binding-dependent mechanism of GR-mediated FasL repression.\",\n      \"method\": \"FasL promoter deletion and mutagenesis; transient transfection reporter assays; electrophoretic mobility shift assay (EMSA); chromatin immunoprecipitation (ChIP); dominant-negative GR constructs\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1–2 — promoter mutagenesis, ChIP, and EMSA; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"16770006\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The FasL intracellular polyproline domain interacts with SH3 domains of Tec kinases and sorting nexins, as identified by phage display screening and verified by cellular pulldown assays; these interactions may regulate FasL function, transport, or processing.\",\n      \"method\": \"Human SH3 domain phage display library screen; pulldown experiments in cellular systems for Tec kinases and sorting nexins\",\n      \"journal\": \"BMC immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — phage display followed by cellular pulldown verification; single lab\",\n      \"pmids\": [\"19807924\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"FasL palmitoylation within its transmembrane domain is critical for efficient FasL-mediated killing and for FasL processing by ADAM10; FasL processing by ADAM10 occurs preferentially within cholesterol/sphingolipid-rich nanodomains (rafts) where Fas-FasL contact is efficient, and Fas-FasL interaction is required for efficient FasL processing.\",\n      \"method\": \"Palmitoylation mutants of FasL; ADAM10 processing assay; raft fractionation; FasL-EGFP cleavage reporter; cytotoxicity assays; siRNA knockdown\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — mutagenesis of palmitoylation site with functional assays and membrane domain analysis; multiple orthogonal methods\",\n      \"pmids\": [\"21368861\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Antigen-specific cytotoxicity of iNKT cells in vivo depends almost exclusively on the CD95/CD178 (Fas/FasL) pathway, correlates with CD1d expression levels and TCR affinity for glycolipid antigen, and can be used for tumor protection.\",\n      \"method\": \"In vivo cytotoxicity assay with iNKT cells from spleen, liver, thymus; genetic deficiency experiments (FasL-deficient vs. perforin-deficient mice); flow cytometry; tumor protection assay\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic loss-of-function in vivo with quantitative cytotoxicity readout; replicated across multiple tissue compartments\",\n      \"pmids\": [\"20660713\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ERα signaling in osteoblasts regulates FasL cleavage and solubilization via upregulation of MMP3: 17β-estradiol (E2) activates ERα to increase MMP3 expression, MMP3 then cleaves membrane-bound FasL to release soluble FasL, which induces osteoclast apoptosis.\",\n      \"method\": \"EGFP-FasL cleavage reporter assay; specific MMP3 inhibitor; MMP3 siRNA knockdown; primary osteoblast cultures from ERαKO mice; conditioned media FasL quantification; osteoclast/osteoblast co-culture apoptosis assay\",\n      \"journal\": \"Journal of bone and mineral research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal approaches including genetic KO, siRNA, pharmacologic inhibition, and functional co-culture assays\",\n      \"pmids\": [\"22927007\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Tumor endothelial FasL expression is cooperatively induced by tumor-derived VEGF-A, IL-10, and PGE2, enabling tumor vasculature to kill effector CD8+ T cells while sparing FoxP3+ Treg cells (which are protected by higher c-FLIP expression), establishing a tumor endothelial immune barrier.\",\n      \"method\": \"Immunostaining of human and mouse tumors; in vitro induction of FasL in endothelial cells by recombinant VEGF-A/IL-10/PGE2; cytotoxicity assays; genetic/pharmacologic FasL suppression in mice with CD8/Foxp3 T cell quantification; c-FLIP expression analysis in Tregs\",\n      \"journal\": \"Nature medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal in vitro and in vivo approaches; mechanistic pathway validated; highly cited\",\n      \"pmids\": [\"24793239\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Activated platelets express membrane-bound FasL on their surface; platelet-derived membrane-bound FasL induces Fas-dependent apoptosis in neurons, fibroblasts, and neuroblastoma cells; in vivo platelet depletion or platelet-specific FasL deletion (PF4Cre+ FasLfl/fl) reduces tissue apoptosis in stroke and retinal injury models.\",\n      \"method\": \"Flow cytometry of activated platelets; apoptosis assays with platelet membrane fractions on target cells; FasLΔm/Δm platelet knockout; PF4Cre+ FasLfl/fl conditional knockout mice; stroke model and NMDA retinal injury model\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic conditional KO with multiple in vivo models and in vitro mechanistic assays\",\n      \"pmids\": [\"26232171\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Crystal structure of FasL in complex with its decoy receptor DcR3 was solved; structural comparison reveals that DcR3 recognizes invariant main-chain and conserved side-chain functionalities to bind multiple TNF ligands; structure-inspired FasL mutations and native glycosylation enhance FasL's ability to induce Jurkat cell apoptosis by reducing aggregation.\",\n      \"method\": \"X-ray crystallography of FasL:DcR3 complex; mutagenesis of FasL based on structure; Jurkat cell apoptosis assay with glycosylated vs. non-glycosylated FasL variants\",\n      \"journal\": \"Structure\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure with functional mutagenesis validation\",\n      \"pmids\": [\"27806260\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Platelet FasL and RBC FasR (CD95) mediate a direct cell-contact pathway in thrombus formation: platelet activation exposes FasL which activates Fas on RBCs, causing phosphatidylserine externalization on RBCs; genetic deletion of FasL or FasR reduces thrombin generation and thrombus formation in vitro and in vivo.\",\n      \"method\": \"FasL-/- and FasR-/- mice; in vitro thrombus formation assay; flow cytometry for PS exposure; thrombin generation assay; carotid artery injury and IVC ligation models; surgical specimens from thrombectomy patients\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO studies in multiple in vivo thrombosis models plus in vitro mechanistic assays; multiple orthogonal approaches\",\n      \"pmids\": [\"29952767\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"High-dose osteocalcin (GluOC) triggers FasL upregulation on adipocyte plasma membranes via GPRC6A→cAMP→PKA→CREB-p300→FoxO1 signaling cascade; surface FasL then activates Fas on neighboring adipocytes, triggering MLKL phosphorylation/homotrimerization and Ca2+ influx (via TRPM7), generating ROS and inducing necroptosis.\",\n      \"method\": \"GPRC6A signaling pathway dissection; pharmacological inhibitors of PKA, ERK, SIK2; p300 activation assay; FoxO1/FasL Western blot; MLKL phosphorylation and homotrimerization assay; Ca2+ imaging; mitochondrial fragmentation analysis\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — systematic pathway dissection with multiple inhibitors in single cellular system; single lab\",\n      \"pmids\": [\"30546087\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"TNFα sensitizes hepatocytes to FasL-induced apoptosis through NFκB-mediated transcriptional upregulation and increased surface expression of Fas; genetic deletion, knockdown, or dominant-negative inhibition of NFκB p65 reduces Fas expression and blocks TNFα-induced sensitization, confirmed in vivo by hydrodynamic injection of p65 shRNA.\",\n      \"method\": \"Primary hepatocytes and cell lines; p65 knockout/siRNA/dominant-negative; Western blot for Fas; hydrodynamic tail-vein injection of p65 shRNA in mice; FasL-induced apoptosis assay\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic loss-of-function with in vitro and in vivo validation; single lab, multiple orthogonal approaches\",\n      \"pmids\": [\"30185788\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"DNA origami nanoagents with nanometer-precise hexagonal FasL arrangements with 10 nm inter-molecular spacing produce the fastest apoptosis kinetics and are 100× more efficient than soluble FasL, demonstrating that hexagonal receptor geometry and specific spacing are critical determinants of FasL-mediated death-inducing signaling complex (DISC) activation.\",\n      \"method\": \"DNA origami scaffolds with defined FasL arrangements; cell viability and time-to-death kinetics assays; comparison of different geometries (hexagonal, linear, random), spacings, and FasL valencies\",\n      \"journal\": \"Small\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution with precise structural control; multiple geometries and spacings systematically tested\",\n      \"pmids\": [\"34057291\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"FasL promoter activation by IL-2 is mediated through SP1 and NFAT binding to a GGGCGGAAA overlapping response element; mutation of the SP1 site (GGGCGG) or NFAT site (GGAAA) each partially reduced IL-2-induced FasL promoter activity, while mutation of both abolished it; the Egr site is not required for IL-2-induced activation.\",\n      \"method\": \"Transient transfection with FasL promoter deletion/mutation constructs; IL-2-treated peripheral T cells; nuclear expression analysis of SP1, NFAT, Egr-2, Egr-3\",\n      \"journal\": \"European journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — promoter mutagenesis with functional reporter assays; single lab\",\n      \"pmids\": [\"10556800\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"HIV-1 Nef induces FasL expression and T-cell bystander killing through a p38 MAPK→AP-1 pathway: p38 is required for Nef-induced AP-1 activation; the FasL promoter AP-1 enhancer element is required for Nef-mediated transcriptional activation, and p38 inhibition attenuates HIV-1-mediated bystander CD8 T-cell killing.\",\n      \"method\": \"Dominant-negative p38 isoforms; p38 siRNA; chemical inhibitors of p38; FasL promoter AP-1 element mutagenesis; reporter assays; HIV-1 bystander CD8 killing assay in vitro\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple loss-of-function approaches plus promoter mutagenesis; single lab\",\n      \"pmids\": [\"15928037\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"TGF-β3 signaling is required for FasL-Fas-caspase extrinsic apoptosis pathway activation during palatogenesis: FasL-Fas-caspase activity is detectable in wild-type palate fusion but absent in Tgf-β3-/- and K14-Cre;Tgfbr2fl/fl mice; FasL-Fas system inhibition causes persistence of the midline epithelial seam, and ectopic FasL rescues apoptosis in Tgfbr2-deficient epithelium.\",\n      \"method\": \"Tgf-β3 knockout and conditional Tgfbr2 knockout mice; FasL-Fas inhibition in palatal organ culture; ectopic FasL protein application; caspase activity measurement\",\n      \"journal\": \"Journal of dental research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with rescue experiment; multiple genetic models\",\n      \"pmids\": [\"21593251\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"FasL synergizes with IFN-γ to activate macrophages to a microbicidal state (enhanced TNF, IL-6, NO secretion and killing of intracellular Leishmania major), while IL-4 suppresses this FasL/IFN-γ synergy, establishing a non-apoptotic signaling function for FasL in macrophage activation.\",\n      \"method\": \"Bone marrow-derived macrophage stimulation with FasL ± IFN-γ or IL-4; cytokine/NO measurement; intracellular parasite killing assay\",\n      \"journal\": \"Journal of leukocyte biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional in vitro assay with defined ligands and cytokine readouts; single lab\",\n      \"pmids\": [\"19380712\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"In cerebral ischemia/reperfusion, FasL mediates procaspase-3 denitrosylation and activation via the GluR6-FasL-Trx2 pathway: GluR6 antagonism inhibits I/R-induced FasL and Trx2 upregulation; FasL antisense oligodeoxynucleotides and TrxR2 knockdown inhibit procaspase-3 denitrosylation and reduce neuronal apoptosis.\",\n      \"method\": \"GluR6 antagonist (NS102); FasL antisense oligodeoxynucleotides; TrxR inhibitor (auranofin); TrxR2 antisense; lentiviral FasL/TrxR2 knockdown; S-nitrosylation assay; TUNEL staining; cresyl violet staining in rat hippocampus\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple loss-of-function approaches in vivo and in vitro; single lab\",\n      \"pmids\": [\"23949220\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"D-type cyclins repress FasL and Fas expression in hematopoietic cells; acute shutdown of all three D-cyclins in adult mouse bone marrow upregulates Fas and FasL expression, leading to Fas- and caspase-8-dependent apoptosis of hematopoietic stem and progenitor cells including quiescent HSCs.\",\n      \"method\": \"Conditional triple D-cyclin knockout in adult bone marrow; Fas/FasL mRNA and protein measurement; caspase-8 activation assay; flow cytometry of HSC populations\",\n      \"journal\": \"Developmental cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic loss-of-function with mechanistic downstream pathway validation; single lab\",\n      \"pmids\": [\"25087893\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FASLG encodes a type II transmembrane TNF-family protein expressed predominantly on activated cytotoxic T and NK cells that induces apoptosis by binding preassembled trimeric Fas/CD95 receptor, recruiting FADD and caspase-8 into a death-inducing signaling complex (DISC); membrane-bound FasL is the functionally active form (soluble FasL generated by metalloproteinase/MMP cleavage is less potent and can inhibit membrane FasL activity), its surface expression and trafficking are regulated by SH3-domain interactions (Grb2, FBP17, PACSIN2, Tec kinases, sorting nexins) with the cytoplasmic polyproline region, palmitoylation within the transmembrane domain controls raft localization and ADAM10 processing, transcription is controlled by NFAT/SP1 (IL-2), AP-1 (Nef/p38), NFκB, and GR, and beyond AICD and cytotoxic T/NK cell killing the protein performs non-apoptotic functions including macrophage activation, platelet-RBC procoagulant signaling, tumor endothelial immune barrier formation, and developmental apoptosis during palatogenesis.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"FASLG encodes FasL (CD178/CD95L), a TNF superfamily type II transmembrane protein that functions as the principal death ligand of the Fas/CD95 receptor, mediating extrinsic apoptosis and related cell-death programs across immune, hematopoietic, vascular, and developmental contexts. Membrane-bound FasL assembles as trimers whose hexagonal nanoscale geometry (~10 nm spacing) is critical for efficient death-inducing signaling complex (DISC) formation via FADD and caspase-8 [PMID:34057291, PMID:11593384]; engagement of preassembled Fas receptor trimers [PMID:10917832] triggers caspase-dependent apoptosis essential for activation-induced T-cell death (AICD), cytotoxic killing by CD4+ T, CD8+ T, and iNKT cells, platelet-mediated procoagulant signaling on red blood cells, and palatal epithelial fusion [PMID:7530337, PMID:20660713, PMID:29952767, PMID:21593251]. FasL surface levels are controlled transcriptionally by SP1/NFAT, NF-κB (repressed by glucocorticoid receptor occlusion), AP-1 (downstream of p38 MAPK), and FoxO1/FoxO3a (downstream of PI3K–PKB–ERK5), and post-translationally by palmitoylation-dependent lipid raft partitioning that governs ADAM10-mediated ectodomain shedding, endocytic internalization, and intracellular trafficking regulated through SH3/WW-domain adaptors (Grb2, FBP17, PACSIN2) binding the cytoplasmic polyproline region [PMID:10556800, PMID:16770006, PMID:15928037, PMID:16710360, PMID:21368861, PMID:12023017]. Homozygous loss-of-function mutations in FASLG cause autoimmune lymphoproliferative syndrome (ALPS) due to defective AICD [PMID:22857792].\",\n  \"teleology\": [\n    {\n      \"year\": 1995,\n      \"claim\": \"Establishing FasL as the molecular effector of activation-induced cell death resolved how T cells self-limit after antigen stimulation, providing the first functional proof that a specific ligand–receptor pair governs AICD.\",\n      \"evidence\": \"Soluble Fas-Ig decoy receptor blockade in TCR-crosslinked T-cell hybridomas selectively prevented death without affecting activation\",\n      \"pmids\": [\"7530337\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream signaling intermediates between Fas engagement and cell death were not identified\", \"Whether FasL functions identically in primary human T cells was not tested\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Mapping the transcriptional regulation of FasL to SP1/NFAT elements in the promoter explained how IL-2 upregulates FasL during T-cell activation, linking cytokine signaling to the death-ligand program.\",\n      \"evidence\": \"Promoter deletion/point-mutation constructs and nuclear factor binding assays in transfected cells\",\n      \"pmids\": [\"10556800\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo chromatin context of SP1/NFAT at the endogenous locus was not assessed\", \"Contribution of additional distal enhancers not explored\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Demonstration that Fas preassembles as trimers independent of ligand binding redefined the signaling model: FasL does not induce receptor trimerization but rather activates pre-formed receptor complexes, constraining models of DISC assembly.\",\n      \"evidence\": \"Biochemical and structural analyses of Fas oligomerization from two independent laboratories\",\n      \"pmids\": [\"10917832\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How FasL binding converts preassembled Fas trimers into signaling-competent higher-order clusters was undefined\", \"Stoichiometry of FasL trimer–Fas trimer complexes not resolved\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Genetic studies in leukemia models revealed that CD4+ T cells rely primarily on FasL for graft-versus-leukemia activity while CD8+ T cells use perforin, demonstrating subset-specific cytolytic pathway usage and establishing FasL as the dominant CD4 effector mechanism.\",\n      \"evidence\": \"Perforin-KO and FasL-deficient mice in syngeneic GVL tumor challenge with in vivo and in vitro cytolysis assays\",\n      \"pmids\": [\"10910921\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether this CD4-FasL dominance generalizes to solid tumors was not tested\", \"Contribution of TRAIL or other death ligands not excluded\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Identifying FADD and caspase-8 as essential mediators downstream of FasL, and distinguishing type I (mitochondria-independent) from type II (Bcl-2-protectable) responses, clarified cell-type-specific wiring of the FasL death pathway.\",\n      \"evidence\": \"FasL treatment of glioma cell line panel with Bcl-2 overexpression and caspase inhibitors\",\n      \"pmids\": [\"11593384\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Determinants of type I vs type II assignment in non-glioma cells remained undefined\", \"Role of caspase-10 not addressed\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Discovery that the cytoplasmic polyproline region of FasL recruits SH3-domain adaptors (Grb2, FBP17, PACSIN2) established a previously unknown intracellular signaling and trafficking platform for FasL, separate from its extracellular death function.\",\n      \"evidence\": \"Pulldown with FasL cytoplasmic tail constructs, mass spectrometry, co-IP, and SH3 domain mutagenesis\",\n      \"pmids\": [\"12023017\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequences of individual adaptor interactions for FasL surface expression were not quantified\", \"Whether these interactions occur in primary immune cells was not shown\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Establishing that HIV-1 Nef activates FasL transcription through a linear p38 MAPK→AP-1 pathway explained how HIV drives bystander T-cell killing, linking viral pathogenesis to a defined host promoter element.\",\n      \"evidence\": \"Dominant-negative p38, siRNA, chemical inhibitors, and AP-1 site mutagenesis in the FasL promoter with bystander killing assays\",\n      \"pmids\": [\"15928037\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether other MAPK cascades contribute in primary CD4+ T cells was not tested\", \"Direct AP-1 ChIP at the endogenous FasL locus was not performed\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Defining the ERK5→PKB→FoxO3a→FasL axis showed that survival kinase signaling tonically represses FasL transcription, and loss of this brake (e.g., osmotic stress) creates a positive feedback loop amplifying apoptosis.\",\n      \"evidence\": \"erk5-/- and mek5-/- fibroblasts with PKB and Foxo3a activity measurements under osmotic stress\",\n      \"pmids\": [\"16710360\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ERK5-FasL axis operates in lymphocyte AICD was not tested\", \"Direct FoxO3a binding to the FasL promoter not demonstrated by ChIP\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Showing that the glucocorticoid receptor represses FasL by sterically occluding NF-κB at a shared −990 element provided a molecular mechanism for immunosuppressive glucocorticoid action on FasL-dependent killing.\",\n      \"evidence\": \"Promoter mutagenesis, in vitro DNA binding, chromatin immunoprecipitation, co-transfection with GR and NF-κB constructs\",\n      \"pmids\": [\"16770006\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance in GR-treated immune cells was not formally demonstrated\", \"Whether GR also affects FasL mRNA stability was not examined\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Expanding the SH3-domain interactome of FasL to include Tec kinases and sorting nexins broadened the model of FasL intracellular regulation beyond adaptor scaffolding to include kinase signaling and vesicular sorting.\",\n      \"evidence\": \"SH3 phage display library screen with cellular pulldown validation\",\n      \"pmids\": [\"19807924\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional validation of Tec kinase or sorting nexin interactions on FasL trafficking was lacking\", \"Endogenous complex formation in immune cells not shown\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Demonstrating that palmitoylation targets FasL to lipid rafts where ADAM10-mediated shedding occurs, and that shedding antagonizes killing activity, resolved how post-translational lipid modification toggles FasL between its pro-apoptotic membrane form and immunosuppressive soluble form.\",\n      \"evidence\": \"Palmitoylation site mutagenesis, ADAM10 inhibitors, membrane fractionation, and cell death assays\",\n      \"pmids\": [\"21368861\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the palmitoyl transferase catalyzing FasL palmitoylation unknown\", \"In vivo consequences of blocking FasL shedding not addressed\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Showing that iNKT cell cytotoxicity in vivo depends almost exclusively on the Fas/FasL pathway extended FasL's effector role beyond conventional T cells and NK cells to innate-like lymphocytes, linking it to lipid-antigen-driven tumor protection.\",\n      \"evidence\": \"FasL-deficient mice in vivo cytotoxicity assays with CD1d-restricted iNKT responses and tumor protection models\",\n      \"pmids\": [\"20660713\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether iNKT FasL dependence holds for all tumor types not established\", \"Contribution of TRAIL in iNKT killing not fully excluded\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Placing FasL-Fas-caspase signaling downstream of TGF-β3/TGFβR2 during palatal fusion demonstrated a non-immune developmental function for FasL in midline epithelial seam elimination, broadening its physiological roles beyond the immune system.\",\n      \"evidence\": \"Tgf-β3 KO and conditional TgfβR2 KO mice, pathway inhibition in palatal organ culture, rescue with ectopic FasL\",\n      \"pmids\": [\"21593251\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether FasL mediates epithelial apoptosis in other fusion events (neural tube) not tested\", \"Direct transcriptional link from TGF-β to FasL promoter not established\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identification of a homozygous FASLG loss-of-function mutation causing ALPS in a human patient provided definitive genetic proof that FasL is essential for lymphocyte homeostasis in humans, not only in mice.\",\n      \"evidence\": \"FASLG sequencing, absent FasL protein by Western blot, defective reactivation-induced cell death assay\",\n      \"pmids\": [\"22857792\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Only a single kindred reported; full phenotypic spectrum of human FASLG deficiency incompletely characterized\", \"Genotype–phenotype correlation across different FASLG mutation types unknown\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Demonstrating that ERα-induced MMP3 cleaves membrane FasL from osteoblasts to generate a soluble form that kills osteoclasts revealed a paracrine FasL mechanism in estrogen-regulated bone homeostasis.\",\n      \"evidence\": \"MMP3 siRNA and inhibitor, ERαKO osteoblasts, conditioned media apoptosis assays, EGFP-FasL reporter\",\n      \"pmids\": [\"22927007\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether soluble FasL generated by MMP3 vs ADAM10 differs in activity not compared\", \"In vivo bone phenotype of MMP3 KO not assessed for FasL-dependent osteoclast apoptosis\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Showing that tumor-derived VEGF-A, IL-10, and PGE2 cooperatively induce endothelial FasL to selectively kill effector CD8+ T cells while sparing Tregs (protected by c-FLIP) established FasL as a key mediator of tumor immune evasion at the vascular interface.\",\n      \"evidence\": \"FasL-/- mice, pharmacological VEGF/PGE2 inhibition, in vitro endothelial cytotoxicity, c-FLIP expression analysis, tumor T-cell infiltration assays\",\n      \"pmids\": [\"24793239\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether anti-VEGF therapy in patients restores T-cell infiltration specifically through FasL reduction not shown\", \"Additional endothelial death ligands not excluded\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Conditional platelet-specific FasL deletion demonstrated that activated platelets present membrane-bound FasL that induces Fas-mediated apoptosis in neurons and other cell types in vivo, extending FasL function from immune homeostasis to thrombosis-associated tissue injury.\",\n      \"evidence\": \"PF4Cre+ FasLfl/fl mice, isolated platelet membrane fractions, stroke and retinal NMDA injury models\",\n      \"pmids\": [\"26232171\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of FasL surface mobilization on activated platelets not defined\", \"Whether platelet FasL contributes to immune-mediated platelet clearance unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"The crystal structure of FasL bound to decoy receptor DcR3 revealed that DcR3 recognizes conserved main-chain and side-chain features shared across TNF ligands, explaining cross-reactivity and providing a structural basis for therapeutic FasL modulation.\",\n      \"evidence\": \"X-ray crystallography of FasL–DcR3 complex, structure-guided mutagenesis, apoptosis assays with engineered FasL variants\",\n      \"pmids\": [\"27806260\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Crystal structure of FasL bound to its cognate receptor Fas/CD95 not yet solved\", \"Structural basis of type I vs type II signaling distinction at the DISC level unknown\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Discovery that platelet FasL triggers RBC phosphatidylserine exposure to enhance thrombin generation and arterial thrombosis in vivo established a non-apoptotic procoagulant function for FasL in hemostasis.\",\n      \"evidence\": \"FasL-/- and FasR-/- mice in ferric chloride and IVC ligation thrombosis models, platelet-RBC co-incubation assays\",\n      \"pmids\": [\"29952767\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether FasL-induced PS exposure on RBCs involves caspase activation or a distinct scramblase pathway not resolved\", \"Clinical relevance in human thrombotic disease not demonstrated\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Using DNA origami to control FasL nanoscale geometry demonstrated that hexagonal arrangement with ~10 nm spacing maximizes DISC activation (100× over soluble FasL), establishing that ligand spatial organization — not just valency — is a critical determinant of death-receptor signaling efficiency.\",\n      \"evidence\": \"DNA origami nanoagents with precisely positioned FasL molecules, quantitative apoptosis kinetics across multiple geometric conditions\",\n      \"pmids\": [\"34057291\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether this geometry requirement reflects higher-order Fas clustering (SPOTS/DISC microaggregates) not resolved structurally\", \"Optimal geometry for non-apoptotic FasL signaling not tested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the full-length FasL–Fas co-crystal structure, the identity of the palmitoyl transferase modifying FasL, the mechanism by which intracellular SH3-domain adaptor complexes regulate FasL vesicular trafficking to the plasma membrane, and how the switch between apoptotic and non-apoptotic Fas signaling is determined at the molecular level.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No FasL–Fas co-crystal structure available\", \"Palmitoyl transferase identity unknown\", \"Mechanism linking SH3 adaptor binding to FasL surface delivery uncharacterized\", \"Molecular determinants of apoptotic vs non-apoptotic Fas signaling switch undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 5, 8, 14, 15, 18]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [4, 14, 15, 16, 18]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [0, 5, 9, 15, 17, 18]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [0, 5, 8, 19, 24]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [10, 11, 12, 13, 20]},\n      {\"term_id\": \"R-HSA-109582\", \"supporting_discovery_ids\": [14]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"FAS\",\n      \"GRB2\",\n      \"FBP17\",\n      \"PACSIN2\",\n      \"ADAM10\",\n      \"DCR3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"FASLG encodes a type II transmembrane TNF superfamily ligand that triggers apoptosis by engaging preassembled trimeric Fas/CD95 receptors, with membrane-bound FasL being the principal cytotoxic form while metalloproteinase-cleaved soluble FasL is less potent and can antagonize membrane FasL activity [PMID:7505205, PMID:9427603]. In cytotoxic T cells, NK cells, and iNKT cells, FasL mediates target cell killing and activation-induced cell death (AICD), with transcription controlled by NFAT/SP1 (IL-2 signaling), AP-1 (p38 MAPK), NFκB, and glucocorticoid receptor, and surface delivery regulated by SH3-domain interactions of its cytoplasmic polyproline region with Grb2, FBP17, PACSIN2, Tec kinases, and sorting nexins, as well as by palmitoylation-dependent lipid raft localization that governs ADAM10 processing [PMID:7530337, PMID:10556800, PMID:15928037, PMID:16770006, PMID:12023017, PMID:21368861]. Beyond canonical immune cytotoxicity, FasL establishes immune privilege in tissues such as testis, mediates tumor endothelial immune barrier formation through VEGF-A/IL-10/PGE2-induced expression, drives platelet-RBC procoagulant signaling via Fas-dependent phosphatidylserine externalization on erythrocytes, participates in TGF-β3-dependent apoptosis during palatal fusion, and activates macrophages to a microbicidal state in synergy with IFN-γ [PMID:7566174, PMID:24793239, PMID:29952767, PMID:21593251, PMID:19380712]. Hexagonal FasL arrangements at 10 nm spacing on DNA origami scaffolds produce optimal DISC activation, demonstrating that precise receptor clustering geometry is a critical determinant of signaling potency [PMID:34057291].\",\n  \"teleology\": [\n    {\n      \"year\": 1993,\n      \"claim\": \"Identification of FasL as the TNF-family ligand for Fas/CD95 resolved the molecular identity of the death-inducing signal on cytotoxic T cells and established the Fas–FasL axis as a major apoptosis pathway.\",\n      \"evidence\": \"Expression cloning from cytotoxic T hybridoma; recombinant FasL in COS cells induces apoptosis in Fas+ targets\",\n      \"pmids\": [\"7505205\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream signaling intermediates (FADD, caspase-8 DISC assembly) not yet defined\", \"Regulation of FasL expression unknown at this point\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Demonstration that FasL mediates T-cell activation-induced cell death (AICD) and maintains immune privilege in testis established its dual role in immune homeostasis and tissue protection.\",\n      \"evidence\": \"Soluble Fas-Ig blockade prevents AICD in T hybridomas and human T clones; gld (FasL-deficient) testis grafts rejected whereas wild-type grafts survive indefinitely\",\n      \"pmids\": [\"7530337\", \"7530336\", \"7528780\", \"7566174\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which HIV exploits FasL for CD4 depletion only partially characterized\", \"Relative contribution of FasL vs. perforin in different CTL contexts not resolved\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Discovery that tumors express FasL to kill infiltrating Fas+ T cells ('Fas counterattack') revealed FasL as a mechanism of tumor immune evasion.\",\n      \"evidence\": \"FasL+ melanoma cells induce T-cell apoptosis in vitro; tumor growth is delayed in Fas-deficient lpr mice in vivo\",\n      \"pmids\": [\"8910274\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Generalizability across tumor types debated\", \"Whether tumor FasL expression is sufficient vs. necessary for immune escape not fully dissected\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Identification of metalloproteinase-mediated FasL cleavage and the DcR3 decoy receptor established two independent mechanisms of FasL activity regulation: proteolytic shedding reduces killing potency, and soluble decoy receptor neutralizes ligand.\",\n      \"evidence\": \"FasL cleavage-site mutant retains full membrane-bound cytotoxicity; soluble FasL inhibits membrane FasL; DcR3 binds FasL and blocks apoptosis; DcR3 gene amplified in lung/colon tumors\",\n      \"pmids\": [\"9427603\", \"9872321\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the specific metalloproteinase(s) responsible in vivo not fully defined at this stage\", \"Physiological contexts where DcR3 dominantly regulates FasL not established\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Mapping of NFAT and SP1 binding to an overlapping FasL promoter element downstream of IL-2 signaling defined the transcriptional logic for activation-induced FasL expression in T cells.\",\n      \"evidence\": \"FasL promoter mutagenesis in IL-2-stimulated peripheral T cells; mutation of both SP1 and NFAT sites abolishes IL-2 response\",\n      \"pmids\": [\"10556800\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Chromatin-level regulation and epigenetic control of the FasL locus not addressed\", \"In vivo validation of SP1/NFAT requirement in T-cell AICD not performed\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Evidence that Fas preassembles into trimers independently of FasL binding reframed the signaling model: FasL engages a pre-formed receptor complex rather than inducing receptor trimerization de novo.\",\n      \"evidence\": \"Biochemical and cellular Fas preassembly studies reviewed/synthesized\",\n      \"pmids\": [\"10917832\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Stoichiometry of FasL trimer binding to preassembled Fas trimers not resolved\", \"Higher-order clustering requirements for DISC assembly not defined\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Discovery that FasL traffics through multivesicular bodies and is released on microvesicles, and that SH3-domain proteins FBP17 and PACSIN2 interact with its cytoplasmic polyproline region, established that FasL surface expression and secretion are actively regulated trafficking events.\",\n      \"evidence\": \"Subcellular fractionation showing FasL in melanosomes/MVBs with functional microvesicle release; pulldown/mass spectrometry identifying FBP17 and PACSIN2 as FasL cytoplasmic tail interactors\",\n      \"pmids\": [\"12021310\", \"12023017\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of each SH3 interaction on FasL surface delivery not individually dissected\", \"Whether MVB-derived FasL microvesicles operate physiologically in immune killing unclear\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Mapping of HIV-1 Nef-induced FasL transcription through p38 MAPK→AP-1 defined a viral hijacking mechanism for bystander T-cell killing via the FasL promoter.\",\n      \"evidence\": \"Dominant-negative p38, siRNA, chemical inhibitors, and FasL promoter AP-1 mutagenesis; HIV-1 bystander CD8 killing assay\",\n      \"pmids\": [\"15928037\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo relevance to HIV-associated CD4/CD8 depletion not directly tested\", \"Relative contribution of Tat vs. Nef pathways to FasL induction in infected cells not resolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Identification of glucocorticoid receptor competition with NFκB at a shared FasL promoter element, and ERK5-PKB-Foxo3a-mediated FasL repression, expanded the transcriptional regulatory network governing FasL expression to include stress and hormonal signaling.\",\n      \"evidence\": \"GR-NFκB steric occlusion at position -990 by ChIP and EMSA; ERK5/MEK5 KO fibroblasts show elevated Foxo3a-driven FasL\",\n      \"pmids\": [\"16770006\", \"16710360\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Integration of GR, NFκB, Foxo3a, NFAT, and AP-1 inputs at the endogenous locus not modeled\", \"Tissue-specific dominance of individual transcription factors not established\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Phage display identification of Tec kinases and sorting nexins as additional SH3-domain interactors of FasL's polyproline region broadened the set of candidate trafficking regulators, while demonstration that FasL synergizes with IFN-γ to activate macrophage microbicidal function established a non-apoptotic FasL signaling role.\",\n      \"evidence\": \"SH3 phage display library screen plus cellular pulldown; bone marrow-derived macrophage stimulation with FasL ± IFN-γ showing enhanced NO and parasite killing\",\n      \"pmids\": [\"19807924\", \"19380712\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signaling pathway downstream of Fas in macrophage activation not defined\", \"Functional requirement of individual SH3 interactors for FasL trafficking not validated by loss-of-function\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Demonstration that FasL palmitoylation controls lipid raft localization and ADAM10-mediated processing, and that iNKT cell cytotoxicity depends almost exclusively on FasL, defined critical post-translational and cellular requirements for FasL function.\",\n      \"evidence\": \"Palmitoylation-site mutants reduce raft association, ADAM10 processing, and killing; FasL-deficient mice show near-complete loss of iNKT cytotoxicity in vivo\",\n      \"pmids\": [\"21368861\", \"20660713\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether palmitoylation is dynamically regulated during immune synapse formation unknown\", \"Role of ADAM10 vs. other metalloproteinases in different cell types not systematically compared\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Genetic epistasis showing TGF-β3 signaling is required for FasL-Fas-caspase pathway activation during palatal fusion extended FasL's developmental function beyond immune contexts.\",\n      \"evidence\": \"Tgf-β3 KO and conditional Tgfbr2 KO mice lack palatal FasL-Fas-caspase activity; ectopic FasL rescues apoptosis in Tgfbr2-deficient epithelium\",\n      \"pmids\": [\"21593251\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How TGF-β3 transcriptionally or post-transcriptionally upregulates FasL in palate not defined\", \"Contribution of FasL vs. other apoptotic pathways to normal palatogenesis not quantified\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Discovery that ERα-induced MMP3 cleaves FasL to generate osteoclast-killing soluble FasL in bone, and that FasL participates in ischemic neuronal apoptosis via GluR6-Trx2-dependent procaspase-3 denitrosylation, revealed tissue-specific non-immune FasL functions.\",\n      \"evidence\": \"ERα KO osteoblasts, MMP3 inhibitor/siRNA, osteoclast co-culture; FasL antisense, TrxR2 knockdown, S-nitrosylation assays in rat hippocampal ischemia model\",\n      \"pmids\": [\"22927007\", \"23949220\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo skeletal phenotype of FasL-deficient mice with respect to osteoclast apoptosis not fully characterized\", \"Generality of GluR6-FasL-Trx2 pathway beyond hippocampal ischemia unknown\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identification of tumor endothelial FasL as a VEGF-A/IL-10/PGE2-driven immune barrier that selectively kills CD8+ T cells while sparing Tregs revealed FasL as a key effector of the immunosuppressive tumor vasculature, and D-cyclin repression of FasL in HSCs linked cell-cycle regulators to Fas-dependent apoptotic control of hematopoietic stem cells.\",\n      \"evidence\": \"In vitro endothelial FasL induction; genetic/pharmacologic FasL suppression in tumor-bearing mice; conditional triple D-cyclin KO in bone marrow with Fas/FasL/caspase-8 pathway analysis\",\n      \"pmids\": [\"24793239\", \"25087893\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether endothelial FasL barrier is reversible by anti-angiogenic therapy not demonstrated\", \"Mechanism of D-cyclin-mediated FasL transcriptional repression not identified\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Structural determination of the FasL–DcR3 complex revealed the molecular basis for decoy receptor recognition and enabled structure-guided FasL variants with enhanced apoptotic potency.\",\n      \"evidence\": \"X-ray crystallography of FasL:DcR3 complex; structure-based FasL mutations and glycosylation enhance Jurkat apoptosis\",\n      \"pmids\": [\"27806260\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal structure of FasL bound to its cognate receptor Fas/CD95 available\", \"Structural basis for differential signaling between membrane-bound and soluble FasL not resolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Platelet-expressed FasL was shown to drive both tissue apoptosis (neurons, retina) and procoagulant RBC phosphatidylserine exposure for thrombus formation, establishing FasL as a hemostatic and thrombotic effector beyond the immune system.\",\n      \"evidence\": \"Platelet-specific FasL conditional KO (PF4Cre+ FasLfl/fl); FasL−/− and FasR−/− mice in stroke, retinal injury, and arterial/venous thrombosis models\",\n      \"pmids\": [\"26232171\", \"29952767\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether platelet FasL contributes to pathological thrombosis in human disease not directly tested\", \"Mechanism regulating FasL surface exposure on activated platelets not defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Systematic testing of FasL spatial arrangements on DNA origami established that hexagonal geometry with 10 nm spacing maximizes DISC activation, providing the first nanometer-resolution map of optimal receptor clustering geometry for death signaling.\",\n      \"evidence\": \"DNA origami nanoagents with defined FasL geometries, spacings, and valencies; apoptosis kinetics in target cells\",\n      \"pmids\": [\"34057291\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether these geometric requirements apply to physiological immune synapse FasL clustering unknown\", \"Structural intermediates of DISC assembly at defined FasL geometries not visualized\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"A high-resolution structure of FasL bound to its cognate Fas receptor, the full mechanism by which FasL cytoplasmic SH3 interactions coordinate trafficking to the immune synapse, and the signaling basis for non-apoptotic FasL functions in macrophages and other non-lymphoid cells remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No FasL–Fas co-crystal structure available\", \"Individual contributions of SH3 interactors (Grb2, FBP17, PACSIN2, Tec kinases, sorting nexins) to FasL trafficking not resolved by loss-of-function\", \"Signaling pathway downstream of Fas in non-apoptotic macrophage activation not defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 1, 6, 23]},\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [20]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 6, 14, 18]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [6, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [0, 1, 2, 5, 6, 23]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [1, 2, 3, 5, 15, 17]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [11, 21, 22]},\n      {\"term_id\": \"R-HSA-109582\", \"supporting_discovery_ids\": [20]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [26]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"FAS\", \"DcR3\", \"ADAM10\", \"GRB2\", \"FBP17\", \"PACSIN2\", \"MMP3\"],\n    \"other_free_text\": []\n  }\n}\n```"}