{"gene":"FIG4","run_date":"2026-06-09T23:54:43","timeline":{"discoveries":[{"year":2002,"finding":"Fig4 (Sac1 domain-containing protein) functions as a phosphoinositide phosphatase that mediates turnover of PtdIns(3,5)P2; deletion of FIG4 in vac7Δ yeast suppresses temperature sensitivity, vacuolar morphology defects, and dramatically restores PtdIns(3,5)P2 levels, placing Fig4 as a negative regulator (phosphatase) acting downstream of Fab1 kinase in the PtdIns(3,5)P2 pathway.","method":"Genetic epistasis (suppressor screen, deletion analysis), lipid phosphate measurements in yeast","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — genetic epistasis with direct lipid measurement, replicated in multiple genetic backgrounds","pmids":["11950935"],"is_preprint":false},{"year":2003,"finding":"Fig4 is a magnesium-activated, PtdIns(3,5)P2-selective phosphoinositide phosphatase in vitro; it localizes to the vacuolar limiting membrane via interaction with the scaffold protein Vac14, and Vac14 is required for Fig4 vacuolar localization. Fig4 physically associates with Vac14 in a common membrane-associated complex.","method":"In vitro phosphatase assay, GFP-localization imaging, co-immunoprecipitation, deletion analysis in yeast","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro enzymatic assay, direct localization imaging, and co-IP in a single focused study","pmids":["14528018"],"is_preprint":false},{"year":2007,"finding":"Mammalian FIG4 is the functional homologue of yeast Fig4; loss of Fig4 in the pale tremor mouse leads to abnormal accumulation of PtdIns(3,5)P2 in cultured fibroblasts and LAMP-2-positive vacuoles consistent with dysfunction of the late endosome-lysosome axis, establishing FIG4 as a PtdIns(3,5)P2 5-phosphatase required for endosome-lysosome membrane trafficking in mammals.","method":"Positional cloning, phosphoinositide measurement in fibroblasts, immunofluorescence for LAMP-2, mouse null model","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — positional cloning plus direct lipid measurement plus cellular phenotype, replicated in both mouse and human patient cells","pmids":["17572665"],"is_preprint":false},{"year":2008,"finding":"Fab1 (PIKfyve) binds to Vac14 and Fig4 through its chaperonin-like domain to form a vacuole-associated signaling complex; the complex is tethered to the vacuole via interaction between the FYVE domain in Fab1 and PtdIns(3)P. Vac14 and Fig4 bind each other directly and are mutually dependent for interaction with Fab1, explaining their dual roles in both synthesis and turnover of PtdIns(3,5)P2.","method":"Co-immunoprecipitation, domain-mapping pulldown assays, GFP localization in yeast","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP with domain mapping, multiple orthogonal methods in one study","pmids":["18653468"],"is_preprint":false},{"year":2008,"finding":"FIG4 deficiency leads to impaired trafficking of intracellular organelles in patient fibroblasts, demonstrated by time-lapse imaging showing physical obstruction by vacuoles; axonal degeneration in motor and sensory neurons occurs without TUNEL staining or accumulation of ubiquitinated protein in vacuoles.","method":"Time-lapse live imaging of fibroblasts, histology and electron microscopy of plt mouse neurons","journal":"Brain : a journal of neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct live-cell imaging with functional consequence, single lab, two methods","pmids":["18556664"],"is_preprint":false},{"year":2011,"finding":"The CMT4J-causing FIG4-I41T missense mutation impairs interaction of FIG4 with the scaffold protein VAC14 (shown by yeast two-hybrid), causing protein instability and proteasomal degradation; VAC14 binding is required for FIG4 protein stability in vivo, as FIG4 protein is absent in VAC14 null mouse tissues. Treatment with proteasome inhibitor MG-132 increases FIG4-I41T abundance in cultured cells.","method":"Yeast two-hybrid, Western blot in mouse tissues and patient fibroblasts, proteasome inhibitor treatment, transgenic mouse model","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — yeast two-hybrid, in vivo genetic validation (VAC14 KO mouse), patient fibroblasts, pharmacological rescue, multiple orthogonal methods","pmids":["21655088"],"is_preprint":false},{"year":2011,"finding":"Neuronal expression of Fig4 is both necessary and sufficient to prevent spongiform neurodegeneration; conditional neuron-specific deletion of Fig4 (via Synapsin-Cre) recapitulates full spongiform degeneration and lethality, while astrocyte-specific expression prevents autophagy marker accumulation and microgliosis but not spongiform degeneration.","method":"Transgenic rescue (NSE-promoter, GFAP-promoter), conditional knockout (floxed allele x Synapsin-Cre), histology, survival analysis","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — cell-type-specific genetic gain- and loss-of-function with defined phenotypic readouts, multiple promoter combinations","pmids":["22581779"],"is_preprint":false},{"year":2011,"finding":"Fig4 deficiency leads to distinct pathological changes in different neuron types: sensory neurons (DRG) accumulate vacuoles with membrane disruption from postnatal day 4, whereas spinal motor neurons accumulate electron-dense organelles with elevated LAMP2 and NPC1 (lysosomal proteins) but not mannose-6-phosphate receptor, indicating excessive retention of molecules within lysosomes.","method":"Electron microscopy, immunofluorescence for lysosomal markers (LAMP2, NPC1, M6PR) in plt mouse neurons","journal":"The European journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ultrastructural and immunochemical characterization, single lab, two orthogonal methods","pmids":["21410794"],"is_preprint":false},{"year":2011,"finding":"Fig4 null mice exhibit dramatic reduction of CNS myelin; neuronal (neuron-specific) expression of Fig4 is sufficient to rescue CNS myelination and tremor through a non-cell-autonomous mechanism on oligodendrocyte maturation, demonstrating that Fig4 in neurons supports OL development indirectly.","method":"Transgenic rescue (NSE-Fig4), electron microscopy of optic nerve, action potential recordings, immunohistochemistry for OL markers","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — transgenic genetic rescue with electrophysiological and ultrastructural validation, multiple readouts","pmids":["22131434"],"is_preprint":false},{"year":2012,"finding":"In Drosophila, Fig4 mutations predicted to inactivate phosphatase activity can rescue lysosomal expansion phenotypes, as can mutations in the opposing kinase Fab1, demonstrating that FIG4 serves a phosphatase-independent (biosynthetic/scaffolding) function essential for lysosomal membrane homeostasis. Lysosomal phenotypes are suppressed by genetic inhibition of Rab7 or the HOPS complex, placing FIG4 function after endosome-to-lysosome fusion.","method":"Drosophila transgenic rescue with catalytic-dead alleles, genetic epistasis (Rab7, HOPS, retromer mutants), LysoTracker staining","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — active-site mutagenesis combined with genetic epistasis in vivo, multiple orthogonal genetic tools","pmids":["26662798"],"is_preprint":false},{"year":2014,"finding":"Fig4 has cell-autonomous roles in both motor neurons and Schwann cells: conditional inactivation in motor neurons causes neuronal and axonal degeneration, while conditional inactivation in Schwann cells causes demyelination and defects in autophagy-mediated degradation; Fig4-regulated endolysosomal trafficking in Schwann cells is essential for myelin biogenesis and remyelination after injury.","method":"Cell-type-specific conditional knockout (Cre-lox in motor neurons and Schwann cells), histology, electron microscopy, nerve conduction studies","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — two independent conditional KO lines with distinct phenotypic readouts, single lab with multiple orthogonal methods","pmids":["25187576"],"is_preprint":false},{"year":2015,"finding":"FIG4 deficiency impairs lysosomal fission (but not fusion) associated with increased intralysosomal Ca2+; this is mechanistically linked to reduced PI(3,5)P2 availability for the TRPML1 lysosomal Ca2+ channel. Reactivation of TRPML1 with synthetic ligand ML-SA1 reduces intralysosomal Ca2+, rescues lysosomal storage in FIG4-deficient cells and ex vivo DRGs, and restores dynamin-1 expression/activity required for lysosomal membrane fission.","method":"Flow cytometry (lysosome size), Ca2+ measurements, pharmacological TRPML1 activation (ML-SA1), Western blot for dynamin-1, ex vivo DRG rescue","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (flow cytometry, Ca2+ assay, pharmacological rescue, Western blot) in cell culture and ex vivo tissue","pmids":["25926456"],"is_preprint":false},{"year":2015,"finding":"A catalytically inactive FIG4 (p.Cys486Ser, active-site CX5RT motif mutated) prevents vacuolization in cultured Fig4−/− fibroblasts and rescues neonatal neurodegeneration and juvenile lethality in vivo when expressed neuronally, demonstrating that FIG4's scaffolding/complex-stabilization function (independent of phosphatase activity) provides significant in vivo function. However, late-onset hydrocephalus, defective myelination, and reduced lifespan in these mice demonstrates that phosphatase activity is also required for full long-term function.","method":"Active-site mutagenesis (C486S), transfection rescue assay in fibroblasts, in vivo neuronal transgenic rescue, histology, survival analysis","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 1 / Strong — catalytic active-site mutagenesis with in vitro and in vivo functional rescue, multiple phenotypic readouts","pmids":["26604144"],"is_preprint":false},{"year":2017,"finding":"FIG4 deficiency causes slow turnover of the membrane protein TRPV4, leading to its accumulation at the plasma membrane of patient fibroblasts; knockdown of Fig4 in murine motor neurons caused vacuolation and cell death, and inhibiting TRPV4 activity significantly preserved neuron viability (though without correcting vesicular trafficking), demonstrating a functional interaction between FIG4 and TRPV4.","method":"Immunofluorescence/Western blot of TRPV4 in patient fibroblasts, siRNA knockdown of Fig4 in motor neurons, pharmacological TRPV4 inhibition with viability assay","journal":"Journal of neuropathology and experimental neurology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — multiple methods (IF, knockdown, pharmacology) in single lab","pmids":["28859335"],"is_preprint":false},{"year":2018,"finding":"Global adult inactivation of Fig4 (tamoxifen-inducible CAG-creER) leads to progressive Wallerian degeneration of myelinated PNS fibers, demonstrating a life-long requirement for Fig4 in protecting myelinated axons. In the CNS, adult Fig4 is dispensable for fiber stability under normal conditions but is required for timely remyelination after a chemical white matter lesion.","method":"Inducible conditional knockout (tamoxifen-CAG-creER), histology of sciatic and optic nerve, compound action potential recordings, lysolecithin white matter lesion model","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — inducible KO with functional electrophysiological readout and lesion challenge model, multiple tissue types examined","pmids":["29688489"],"is_preprint":false},{"year":2019,"finding":"In CMT4J patient fibroblasts, SAC3/FIG4 deficiency reduces steady-state PtdIns(3,5)P2 by 36% and PtdIns5P by 43% relative to controls, as measured by HPLC lipid profiling; PtdIns3P levels were variable across individual patients and correlated with presence of aberrant endolysosomal vacuoles.","method":"HPLC phosphoinositide profiling after myo-[2-3H]inositol labeling in patient fibroblasts, Western blot for FIG4 protein","journal":"Molecular neurobiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct biochemical lipid measurement in patient primary cells, cohort of 13 patients vs 9 controls","pmids":["31313076"],"is_preprint":false},{"year":2021,"finding":"VAC14 forms a star-shaped pentamer scaffold where two legs bind FIG4 (with one leg also occupied by PIKfyve); VAC14 oligomerization is critical for Fab1/PIKfyve function, PI(3,5)P2 generation, VAC14 localization, and formation of the PIKfyve-VAC14-FIG4 complex as assessed by pull-down assays; patient mutations at VAC14-VAC14 interfaces disrupt oligomerization and complex assembly.","method":"AlphaFold2 structural prediction, cryo-EM maps, pull-down assays in human VAC14 KO cells, fluorescence-detection size-exclusion chromatography, colocalization with VPS35 endosomes","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — structural prediction validated by cryo-EM plus biochemical pull-down and FSEC in KO cells, multiple orthogonal methods","pmids":["40305106"],"is_preprint":false},{"year":2021,"finding":"Proximity interactome (BioID) of VAC14 and FIG4 identified 89 high-confidence shared interactors; proximity ligation assays validated interaction between VAC14 and COPI subunit COPB1 and between VAC14 and the GTPase Arf1 (required for COPI assembly), suggesting the PIKfyve-VAC14-FIG4 complex interfaces with the COPI coat machinery at endosomes.","method":"BioID proximity labeling, proximity ligation assay, mass spectrometry","journal":"Journal of proteome research","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — BioID is proximity labeling (not direct binding), validated by PLA for two interactions, single lab","pmids":["34554760"],"is_preprint":false},{"year":2023,"finding":"PI(3,5)P2 inhibits the lysosomal chloride transporter ClC-7; loss of FIG4 (or VAC14) reduces PI(3,5)P2 and de-represses ClC-7, contributing to lysosomal swelling and hyperacidification. Knockout of CLCN7 (but not the related CLCN6) corrects lysosomal swelling and partially corrects lysosomal hyperacidification in FIG4-null cells; in vivo, dominant-negative CLCN7 expression improves growth, neurological function, and lifespan in Fig4 null mice by ~20%.","method":"CLCN7 and CLCN6 knockout in FIG4-null cell culture, lysosome size and pH measurements, transgenic dominant-negative CLCN7 in Fig4 null mice, survival and behavioral analysis","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis in both cell culture and in vivo mouse model, two independent genetic tools (KO and dominant-negative), specific control (CLCN6 KO negative result)","pmids":["37363915"],"is_preprint":false},{"year":2023,"finding":"FIG4-regulated PI(3,5)P2 biosynthesis genetically interacts with the phosphoinositide kinase PIP4K2C: haploinsufficiency of Pip4k2c (which elevates PI(3,5)P2) rescues the neonatal lethality of Fig4 null mice and reduces lysosomal enlargement in Fig4 null cells, demonstrating that the opposing kinase PIP4K2C modulates the FIG4 pathway in vivo.","method":"Genetic compound mutant mice (Fig4-/-, Pip4k2c+/-), lysosome size measurement in fibroblasts, survival analysis","journal":"G3 (Bethesda, Md.)","confidence":"High","confidence_rationale":"Tier 2 / Moderate — in vivo genetic epistasis with survival and cellular phenotype readouts, single lab","pmids":["36691351"],"is_preprint":false},{"year":2025,"finding":"Fig4 mutants that fail to bind the Fab1-Vac14-Fig4 complex confer tolerance to rapamycin (TORC1 inhibitor) in yeast independent of Fig4 catalytic activity and Vac14 scaffolding, requiring instead the p21-activated kinase Ste20, demonstrating that Fig4 can modulate TORC1 signaling through a complex-independent, catalysis-independent interaction with unknown partners.","method":"Yeast genetics (point mutations, vac14Δ epistasis), rapamycin growth assays, temperature-shift experiments, kinase deletion (ste20Δ)","journal":"Molecular microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis in yeast with multiple alleles and kinase requirements defined, single lab","pmids":["40741910"],"is_preprint":false},{"year":2026,"finding":"FIG4 overexpression promotes LAMP2A-dependent autophagy-lysosomal degradation of IL-18 and enhances ubiquitination of IL-18, reducing its secretion; FIG4 thus functions as a regulator of IL-18 autophagic-lysosomal turnover in cancer cells.","method":"Overexpression and knockdown of FIG4, Western blot/ELISA for IL-18, lysosomal degradation assays, ubiquitination assays in triple-negative breast cancer cell lines","journal":"Cancer letters","confidence":"Medium","confidence_rationale":"Tier 2–3 / Weak — single lab, single paper, cellular overexpression/knockdown, no in vitro reconstitution or structural validation","pmids":["41577074"],"is_preprint":false}],"current_model":"FIG4 (SAC3/hSac3) is a magnesium-activated, PtdIns(3,5)P2-selective 5-phosphatase that forms an obligate trimeric complex with the kinase PIKfyve/FAB1 and the scaffold protein VAC14 (which forms a pentameric platform); within this complex FIG4 serves dual roles — catalytic turnover of PtdIns(3,5)P2 and a phosphatase-independent scaffolding/biosynthetic function that stabilizes PIKfyve activity and anchors the complex to endolysosomal membranes via PtdIns(3)P recognition. Loss of FIG4 reduces both PtdIns(3,5)P2 and PtdIns5P, impairing TRPML1-mediated lysosomal Ca2+ efflux, de-repressing the ClC-7 chloride transporter, and blocking lysosomal fission (through dynamin-1 downregulation), collectively causing accumulation of enlarged, hyperacidic lysosomes and neurodegeneration in neurons, Schwann cells, and oligodendrocytes."},"narrative":{"mechanistic_narrative":"FIG4 is a magnesium-activated, PtdIns(3,5)P2-selective phosphoinositide 5-phosphatase that governs endolysosomal membrane homeostasis as an obligate component of the PIKfyve(Fab1)–VAC14–FIG4 complex [PMID:11950935, PMID:14528018, PMID:18653468]. Originally defined in yeast as a Sac1-domain phosphatase that mediates turnover of PtdIns(3,5)P2 downstream of the Fab1 kinase [PMID:11950935], FIG4 binds the scaffold VAC14 directly and depends on it for membrane localization and protein stability, while VAC14 oligomerizes into a star-shaped pentamer whose legs engage both FIG4 and PIKfyve to assemble the complex on PtdIns(3)P-bearing endolysosomal membranes [PMID:14528018, PMID:18653468, PMID:40305106]. Despite acting catalytically to consume PtdIns(3,5)P2, FIG4 paradoxically supports its synthesis: loss of FIG4 lowers steady-state PtdIns(3,5)P2 and PtdIns5P, and catalytically dead FIG4 still rescues much of the phenotype, establishing a phosphatase-independent scaffolding/biosynthetic role in stabilizing PIKfyve activity in addition to its catalytic turnover function [PMID:26662798, PMID:26604144, PMID:31313076]. The reduced PtdIns(3,5)P2 in FIG4-deficient cells impairs TRPML1-mediated lysosomal Ca2+ efflux and de-represses the lysosomal chloride transporter ClC-7, producing enlarged, hyperacidic lysosomes through a block in lysosomal fission tied to dynamin-1 downregulation; pharmacological TRPML1 activation or genetic suppression of CLCN7 corrects these defects [PMID:25926456, PMID:37363915]. In mammals FIG4 is required cell-autonomously in motor neurons and Schwann cells and non-cell-autonomously for oligodendrocyte myelination, and its loss causes spongiform neurodegeneration, axonal degeneration, and demyelination [PMID:22581779, PMID:22131434, PMID:25187576]. Loss-of-function and destabilizing missense mutations such as FIG4-I41T, which disrupts VAC14 binding and triggers proteasomal degradation, cause Charcot-Marie-Tooth disease type 4J [PMID:21655088].","teleology":[{"year":2002,"claim":"Established FIG4's core biochemical identity by asking what enzyme controls PtdIns(3,5)P2 turnover, placing it as a phosphatase downstream of the Fab1 kinase.","evidence":"Genetic epistasis/suppressor screen and lipid phosphate measurement in yeast","pmids":["11950935"],"confidence":"High","gaps":["Did not resolve substrate selectivity or whether FIG4 acts directly on the lipid in vitro","Mammalian relevance not addressed"]},{"year":2003,"claim":"Defined FIG4 as a magnesium-activated, PtdIns(3,5)P2-selective phosphatase and showed Vac14 anchors it to the vacuolar membrane, beginning to assemble the complex.","evidence":"In vitro phosphatase assay, GFP localization, and co-IP in yeast","pmids":["14528018"],"confidence":"High","gaps":["Did not include the kinase Fab1/PIKfyve in the architecture","Structural basis of FIG4–Vac14 binding unknown"]},{"year":2007,"claim":"Extended the yeast model to mammals, showing FIG4 is required for endosome-lysosome trafficking and that its loss causes neurodegeneration via vacuolar accumulation.","evidence":"Positional cloning, phosphoinositide measurement, and LAMP-2 imaging in the pale tremor mouse and patient cells","pmids":["17572665"],"confidence":"High","gaps":["Cell-type basis of neurodegeneration not resolved","Counterintuitive accumulation of PtdIns(3,5)P2 in some assays not yet reconciled with the phosphatase role"]},{"year":2008,"claim":"Resolved the tripartite complex architecture by showing Fab1/PIKfyve joins Vac14 and Fig4 through its chaperonin-like domain, with FYVE-domain tethering to PtdIns(3)P, explaining dual synthesis/turnover.","evidence":"Reciprocal co-IP, domain-mapping pulldowns, and GFP localization in yeast","pmids":["18653468"],"confidence":"High","gaps":["Stoichiometry and full structure not determined","How a phosphatase and kinase coexist productively unexplained"]},{"year":2008,"claim":"Connected lysosomal dysfunction to cellular consequence by showing vacuoles physically obstruct organelle trafficking and that neuronal death is non-apoptotic and non-ubiquitin-mediated.","evidence":"Time-lapse live imaging of patient fibroblasts and histology/EM of plt mouse neurons","pmids":["18556664"],"confidence":"Medium","gaps":["Molecular cause of fission/trafficking block not identified","Single-lab observation"]},{"year":2011,"claim":"Established the disease mechanism for CMT4J by showing the I41T mutation disrupts VAC14 binding, destabilizing FIG4 and routing it to proteasomal degradation.","evidence":"Yeast two-hybrid, Western blot in VAC14-null tissue and patient fibroblasts, MG-132 rescue, transgenic mouse","pmids":["21655088"],"confidence":"High","gaps":["Whether residual FIG4 retains partial function in patients unclear","Did not address phosphatase vs scaffolding contribution to disease"]},{"year":2011,"claim":"Defined the cellular site of FIG4 requirement in the nervous system, showing neuronal expression is necessary and sufficient to prevent spongiform degeneration while astrocyte expression is not.","evidence":"Cell-type-specific transgenic rescue and conditional knockout with histology and survival analysis","pmids":["22581779"],"confidence":"High","gaps":["Did not isolate the molecular pathway downstream of neuronal FIG4 loss"]},{"year":2011,"claim":"Revealed non-cell-autonomous neuron-to-glia signaling by showing neuronal Fig4 supports CNS myelination indirectly through oligodendrocyte maturation.","evidence":"NSE-Fig4 transgenic rescue, optic nerve EM, action potential recordings, OL-marker IHC","pmids":["22131434"],"confidence":"High","gaps":["Nature of the neuron-derived signal to oligodendrocytes unknown"]},{"year":2011,"claim":"Showed neuron-type-specific lysosomal pathology, distinguishing sensory neuron membrane disruption from motor neuron lysosomal protein retention.","evidence":"EM and lysosomal-marker immunofluorescence (LAMP2, NPC1, M6PR) in plt mouse neurons","pmids":["21410794"],"confidence":"Medium","gaps":["Basis of neuron-type selectivity unexplained","Single-lab descriptive study"]},{"year":2012,"claim":"Uncovered a phosphatase-independent function by showing catalytic-dead FIG4 (and even the opposing Fab1 kinase) rescues lysosomal expansion, placing FIG4 action after endosome-lysosome fusion.","evidence":"Drosophila catalytic-dead rescue and genetic epistasis with Rab7/HOPS, LysoTracker","pmids":["26662798"],"confidence":"High","gaps":["Molecular basis of the scaffolding/biosynthetic function not isolated","Mammalian confirmation pending at this stage"]},{"year":2014,"claim":"Demonstrated cell-autonomous requirements in both motor neurons and Schwann cells, linking Schwann cell FIG4 to autophagy-dependent myelin biogenesis and remyelination.","evidence":"Cell-type-specific conditional knockouts with histology, EM, and nerve conduction","pmids":["25187576"],"confidence":"High","gaps":["Did not define which lipid pool drives each cell-type phenotype"]},{"year":2015,"claim":"Identified the fission defect mechanism, linking reduced PI(3,5)P2 to impaired TRPML1 Ca2+ efflux and dynamin-1 loss, with pharmacological TRPML1 activation rescuing lysosomal storage.","evidence":"Flow cytometry, Ca2+ assays, ML-SA1 rescue, dynamin-1 Western blot, ex vivo DRG","pmids":["25926456"],"confidence":"High","gaps":["How dynamin-1 expression is coupled to lysosomal Ca2+ not fully mapped"]},{"year":2015,"claim":"Dissected the dual functions in mammals, showing catalytic-dead FIG4 rescues neonatal neurodegeneration (scaffolding role) but not long-term myelination/hydrocephalus (requiring catalysis).","evidence":"C486S active-site mutagenesis, fibroblast and neuronal transgenic rescue, histology, survival","pmids":["26604144"],"confidence":"High","gaps":["Why catalysis is selectively required for long-term myelin maintenance unresolved"]},{"year":2017,"claim":"Identified TRPV4 as a FIG4-regulated membrane protein whose slowed turnover accumulates at the plasma membrane and contributes to neuronal death.","evidence":"TRPV4 IF/Western in patient fibroblasts, Fig4 siRNA in motor neurons, TRPV4 inhibition with viability assay","pmids":["28859335"],"confidence":"Medium","gaps":["TRPV4 inhibition preserved viability without correcting trafficking, so the causal link is partial","Single lab"]},{"year":2018,"claim":"Established a life-long, tissue-differential requirement, showing adult PNS fibers degenerate without Fig4 while CNS fibers need it mainly for remyelination after injury.","evidence":"Inducible CAG-creER knockout, nerve histology, compound action potentials, lysolecithin lesion model","pmids":["29688489"],"confidence":"High","gaps":["Why CNS adult fibers tolerate loss but PNS fibers do not unexplained"]},{"year":2019,"claim":"Quantified the lipid consequence in patients, showing FIG4 deficiency reduces both PtdIns(3,5)P2 and PtdIns5P, with PtdIns3P variability tracking vacuolation.","evidence":"HPLC phosphoinositide profiling in 13 patient vs 9 control fibroblasts","pmids":["31313076"],"confidence":"High","gaps":["Source of inter-patient PtdIns3P variability not resolved"]},{"year":2021,"claim":"Solved the complex architecture, showing VAC14 forms a star-shaped pentamer whose legs bind FIG4 and PIKfyve, and that oligomerization is required for PI(3,5)P2 generation.","evidence":"AlphaFold2/cryo-EM, pull-downs in VAC14 KO cells, FSEC, VPS35 colocalization","pmids":["40305106"],"confidence":"High","gaps":["High-resolution structure of FIG4 within the assembly still incomplete"]},{"year":2021,"claim":"Mapped the complex's broader interactome, linking the PIKfyve-VAC14-FIG4 complex to the COPI coat machinery (COPB1, Arf1) at endosomes.","evidence":"BioID proximity labeling and proximity ligation assay validation","pmids":["34554760"],"confidence":"Medium","gaps":["BioID detects proximity, not direct binding","Functional consequence of COPI interface untested"]},{"year":2023,"claim":"Identified ClC-7 as a key effector, showing PI(3,5)P2 inhibits the transporter and that suppressing CLCN7 corrects lysosomal swelling and extends Fig4-null mouse lifespan.","evidence":"CLCN7/CLCN6 KO in FIG4-null cells, lysosome size/pH assays, dominant-negative CLCN7 in mice","pmids":["37363915"],"confidence":"High","gaps":["Only partial correction of hyperacidification, indicating additional effectors"]},{"year":2023,"claim":"Defined an opposing-kinase modulator, showing Pip4k2c haploinsufficiency elevates PI(3,5)P2 and rescues Fig4-null lethality and lysosomal enlargement.","evidence":"Fig4-/- Pip4k2c+/- compound mutant mice, fibroblast lysosome measurement, survival","pmids":["36691351"],"confidence":"High","gaps":["Mechanism of PIP4K2C control over the PI(3,5)P2 pool not detailed"]},{"year":2025,"claim":"Uncovered a complex- and catalysis-independent role in TORC1 signaling, where Fig4 mutants confer rapamycin tolerance through the kinase Ste20.","evidence":"Yeast point-mutant genetics, vac14Δ/ste20Δ epistasis, rapamycin growth assays","pmids":["40741910"],"confidence":"Medium","gaps":["The unknown partners mediating this function are unidentified","Mammalian relevance untested"]},{"year":2026,"claim":"Extended FIG4 into cancer cell biology, showing FIG4 overexpression drives LAMP2A-dependent autophagic-lysosomal degradation and ubiquitination of IL-18.","evidence":"FIG4 overexpression/knockdown, IL-18 Western/ELISA, degradation and ubiquitination assays in TNBC lines","pmids":["41577074"],"confidence":"Medium","gaps":["No reconstitution or structural validation","Direct vs indirect effect on IL-18 turnover unresolved","Single lab"]},{"year":null,"claim":"How FIG4's catalytic and scaffolding functions are differentially deployed across cell types and how the complex selectively maintains PI(3,5)P2 pools for distinct effectors (TRPML1, ClC-7) remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No high-resolution structure of FIG4 within the assembled complex","Mechanism coupling lipid changes to dynamin-1 and TRPV4 turnover incompletely defined","Complex-independent FIG4 functions (TORC1, IL-18) mechanistically unmapped"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[1]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[3,9,12,16]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[1,3,15]}],"localization":[{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[2,7,11,18]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[3,16,17]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[13]}],"pathway":[{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[2,4,10]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[2,4,11]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[10,21]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[6,8,10]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[20]}],"complexes":["PIKfyve-VAC14-FIG4 (PAS) complex"],"partners":["VAC14","PIKFYVE","COPB1","ARF1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q92562","full_name":"Polyphosphoinositide phosphatase","aliases":["Phosphatidylinositol 3,5-bisphosphate 5-phosphatase","SAC domain-containing protein 3","Serine-protein phosphatase FIG4"],"length_aa":907,"mass_kda":103.6,"function":"Dual specificity phosphatase component of the PI(3,5)P2 regulatory complex which regulates both the synthesis and turnover of phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2) (PubMed:17556371, PubMed:33098764). Catalyzes the dephosphorylation of phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2) to form phosphatidylinositol 3-phosphate (PubMed:33098764). Has serine-protein phosphatase activity acting on PIKfyve to stimulate its lipid kinase activity, its catalytically activity being required for maximal PI(3,5)P2 production (PubMed:33098764). In vitro, hydrolyzes all three D5-phosphorylated polyphosphoinositide and although displaying preferences for PtdIns(3,5)P2, it is capable of hydrolyzing PtdIns(3,4,5)P3 and PtdIns(4,5)P2, at least in vitro (PubMed:17556371)","subcellular_location":"Endosome membrane","url":"https://www.uniprot.org/uniprotkb/Q92562/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FIG4","classification":"Not Classified","n_dependent_lines":65,"n_total_lines":1208,"dependency_fraction":0.05380794701986755},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"PIKFYVE","stoichiometry":4.0},{"gene":"CAPZB","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/FIG4","total_profiled":1310},"omim":[{"mim_id":"612691","title":"POLYMICROGYRIA, BILATERAL TEMPOROOCCIPITAL; BTOP","url":"https://www.omim.org/entry/612691"},{"mim_id":"612577","title":"AMYOTROPHIC LATERAL SCLEROSIS 11; ALS11","url":"https://www.omim.org/entry/612577"},{"mim_id":"611228","title":"CHARCOT-MARIE-TOOTH DISEASE, DEMYELINATING, TYPE 4J; CMT4J","url":"https://www.omim.org/entry/611228"},{"mim_id":"609414","title":"PHOSPHOINOSITIDE KINASE, FYVE FINGER-CONTAINING; PIKFYVE","url":"https://www.omim.org/entry/609414"},{"mim_id":"609390","title":"FIG4 PHOSPHOINOSITIDE 5-PHOSPHATASE; FIG4","url":"https://www.omim.org/entry/609390"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Vesicles","reliability":"Supported"},{"location":"Lipid droplets","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/FIG4"},"hgnc":{"alias_symbol":["SAC3","hSac3","dJ249I4.1","ALS11","CMT4J"],"prev_symbol":["KIAA0274"]},"alphafold":{"accession":"Q92562","domains":[{"cath_id":"-","chopping":"2-201_211-239_643-672","consensus_level":"medium","plddt":88.6425,"start":2,"end":672},{"cath_id":"-","chopping":"251-339_351-559","consensus_level":"medium","plddt":90.74,"start":251,"end":559}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q92562","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q92562-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q92562-F1-predicted_aligned_error_v6.png","plddt_mean":79.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FIG4","jax_strain_url":"https://www.jax.org/strain/search?query=FIG4"},"sequence":{"accession":"Q92562","fasta_url":"https://rest.uniprot.org/uniprotkb/Q92562.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q92562/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q92562"}},"corpus_meta":[{"pmid":"17572665","id":"PMC_17572665","title":"Mutation 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Fig4 physically associates with Vac14 in a common membrane-associated complex.\",\n      \"method\": \"In vitro phosphatase assay, GFP-localization imaging, co-immunoprecipitation, deletion analysis in yeast\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro enzymatic assay, direct localization imaging, and co-IP in a single focused study\",\n      \"pmids\": [\"14528018\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Mammalian FIG4 is the functional homologue of yeast Fig4; loss of Fig4 in the pale tremor mouse leads to abnormal accumulation of PtdIns(3,5)P2 in cultured fibroblasts and LAMP-2-positive vacuoles consistent with dysfunction of the late endosome-lysosome axis, establishing FIG4 as a PtdIns(3,5)P2 5-phosphatase required for endosome-lysosome membrane trafficking in mammals.\",\n      \"method\": \"Positional cloning, phosphoinositide measurement in fibroblasts, immunofluorescence for LAMP-2, mouse null model\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — positional cloning plus direct lipid measurement plus cellular phenotype, replicated in both mouse and human patient cells\",\n      \"pmids\": [\"17572665\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Fab1 (PIKfyve) binds to Vac14 and Fig4 through its chaperonin-like domain to form a vacuole-associated signaling complex; the complex is tethered to the vacuole via interaction between the FYVE domain in Fab1 and PtdIns(3)P. Vac14 and Fig4 bind each other directly and are mutually dependent for interaction with Fab1, explaining their dual roles in both synthesis and turnover of PtdIns(3,5)P2.\",\n      \"method\": \"Co-immunoprecipitation, domain-mapping pulldown assays, GFP localization in yeast\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP with domain mapping, multiple orthogonal methods in one study\",\n      \"pmids\": [\"18653468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"FIG4 deficiency leads to impaired trafficking of intracellular organelles in patient fibroblasts, demonstrated by time-lapse imaging showing physical obstruction by vacuoles; axonal degeneration in motor and sensory neurons occurs without TUNEL staining or accumulation of ubiquitinated protein in vacuoles.\",\n      \"method\": \"Time-lapse live imaging of fibroblasts, histology and electron microscopy of plt mouse neurons\",\n      \"journal\": \"Brain : a journal of neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct live-cell imaging with functional consequence, single lab, two methods\",\n      \"pmids\": [\"18556664\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The CMT4J-causing FIG4-I41T missense mutation impairs interaction of FIG4 with the scaffold protein VAC14 (shown by yeast two-hybrid), causing protein instability and proteasomal degradation; VAC14 binding is required for FIG4 protein stability in vivo, as FIG4 protein is absent in VAC14 null mouse tissues. Treatment with proteasome inhibitor MG-132 increases FIG4-I41T abundance in cultured cells.\",\n      \"method\": \"Yeast two-hybrid, Western blot in mouse tissues and patient fibroblasts, proteasome inhibitor treatment, transgenic mouse model\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — yeast two-hybrid, in vivo genetic validation (VAC14 KO mouse), patient fibroblasts, pharmacological rescue, multiple orthogonal methods\",\n      \"pmids\": [\"21655088\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Neuronal expression of Fig4 is both necessary and sufficient to prevent spongiform neurodegeneration; conditional neuron-specific deletion of Fig4 (via Synapsin-Cre) recapitulates full spongiform degeneration and lethality, while astrocyte-specific expression prevents autophagy marker accumulation and microgliosis but not spongiform degeneration.\",\n      \"method\": \"Transgenic rescue (NSE-promoter, GFAP-promoter), conditional knockout (floxed allele x Synapsin-Cre), histology, survival analysis\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — cell-type-specific genetic gain- and loss-of-function with defined phenotypic readouts, multiple promoter combinations\",\n      \"pmids\": [\"22581779\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Fig4 deficiency leads to distinct pathological changes in different neuron types: sensory neurons (DRG) accumulate vacuoles with membrane disruption from postnatal day 4, whereas spinal motor neurons accumulate electron-dense organelles with elevated LAMP2 and NPC1 (lysosomal proteins) but not mannose-6-phosphate receptor, indicating excessive retention of molecules within lysosomes.\",\n      \"method\": \"Electron microscopy, immunofluorescence for lysosomal markers (LAMP2, NPC1, M6PR) in plt mouse neurons\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ultrastructural and immunochemical characterization, single lab, two orthogonal methods\",\n      \"pmids\": [\"21410794\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Fig4 null mice exhibit dramatic reduction of CNS myelin; neuronal (neuron-specific) expression of Fig4 is sufficient to rescue CNS myelination and tremor through a non-cell-autonomous mechanism on oligodendrocyte maturation, demonstrating that Fig4 in neurons supports OL development indirectly.\",\n      \"method\": \"Transgenic rescue (NSE-Fig4), electron microscopy of optic nerve, action potential recordings, immunohistochemistry for OL markers\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — transgenic genetic rescue with electrophysiological and ultrastructural validation, multiple readouts\",\n      \"pmids\": [\"22131434\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"In Drosophila, Fig4 mutations predicted to inactivate phosphatase activity can rescue lysosomal expansion phenotypes, as can mutations in the opposing kinase Fab1, demonstrating that FIG4 serves a phosphatase-independent (biosynthetic/scaffolding) function essential for lysosomal membrane homeostasis. Lysosomal phenotypes are suppressed by genetic inhibition of Rab7 or the HOPS complex, placing FIG4 function after endosome-to-lysosome fusion.\",\n      \"method\": \"Drosophila transgenic rescue with catalytic-dead alleles, genetic epistasis (Rab7, HOPS, retromer mutants), LysoTracker staining\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — active-site mutagenesis combined with genetic epistasis in vivo, multiple orthogonal genetic tools\",\n      \"pmids\": [\"26662798\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Fig4 has cell-autonomous roles in both motor neurons and Schwann cells: conditional inactivation in motor neurons causes neuronal and axonal degeneration, while conditional inactivation in Schwann cells causes demyelination and defects in autophagy-mediated degradation; Fig4-regulated endolysosomal trafficking in Schwann cells is essential for myelin biogenesis and remyelination after injury.\",\n      \"method\": \"Cell-type-specific conditional knockout (Cre-lox in motor neurons and Schwann cells), histology, electron microscopy, nerve conduction studies\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two independent conditional KO lines with distinct phenotypic readouts, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"25187576\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"FIG4 deficiency impairs lysosomal fission (but not fusion) associated with increased intralysosomal Ca2+; this is mechanistically linked to reduced PI(3,5)P2 availability for the TRPML1 lysosomal Ca2+ channel. Reactivation of TRPML1 with synthetic ligand ML-SA1 reduces intralysosomal Ca2+, rescues lysosomal storage in FIG4-deficient cells and ex vivo DRGs, and restores dynamin-1 expression/activity required for lysosomal membrane fission.\",\n      \"method\": \"Flow cytometry (lysosome size), Ca2+ measurements, pharmacological TRPML1 activation (ML-SA1), Western blot for dynamin-1, ex vivo DRG rescue\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (flow cytometry, Ca2+ assay, pharmacological rescue, Western blot) in cell culture and ex vivo tissue\",\n      \"pmids\": [\"25926456\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"A catalytically inactive FIG4 (p.Cys486Ser, active-site CX5RT motif mutated) prevents vacuolization in cultured Fig4−/− fibroblasts and rescues neonatal neurodegeneration and juvenile lethality in vivo when expressed neuronally, demonstrating that FIG4's scaffolding/complex-stabilization function (independent of phosphatase activity) provides significant in vivo function. However, late-onset hydrocephalus, defective myelination, and reduced lifespan in these mice demonstrates that phosphatase activity is also required for full long-term function.\",\n      \"method\": \"Active-site mutagenesis (C486S), transfection rescue assay in fibroblasts, in vivo neuronal transgenic rescue, histology, survival analysis\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — catalytic active-site mutagenesis with in vitro and in vivo functional rescue, multiple phenotypic readouts\",\n      \"pmids\": [\"26604144\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"FIG4 deficiency causes slow turnover of the membrane protein TRPV4, leading to its accumulation at the plasma membrane of patient fibroblasts; knockdown of Fig4 in murine motor neurons caused vacuolation and cell death, and inhibiting TRPV4 activity significantly preserved neuron viability (though without correcting vesicular trafficking), demonstrating a functional interaction between FIG4 and TRPV4.\",\n      \"method\": \"Immunofluorescence/Western blot of TRPV4 in patient fibroblasts, siRNA knockdown of Fig4 in motor neurons, pharmacological TRPV4 inhibition with viability assay\",\n      \"journal\": \"Journal of neuropathology and experimental neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — multiple methods (IF, knockdown, pharmacology) in single lab\",\n      \"pmids\": [\"28859335\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Global adult inactivation of Fig4 (tamoxifen-inducible CAG-creER) leads to progressive Wallerian degeneration of myelinated PNS fibers, demonstrating a life-long requirement for Fig4 in protecting myelinated axons. In the CNS, adult Fig4 is dispensable for fiber stability under normal conditions but is required for timely remyelination after a chemical white matter lesion.\",\n      \"method\": \"Inducible conditional knockout (tamoxifen-CAG-creER), histology of sciatic and optic nerve, compound action potential recordings, lysolecithin white matter lesion model\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — inducible KO with functional electrophysiological readout and lesion challenge model, multiple tissue types examined\",\n      \"pmids\": [\"29688489\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In CMT4J patient fibroblasts, SAC3/FIG4 deficiency reduces steady-state PtdIns(3,5)P2 by 36% and PtdIns5P by 43% relative to controls, as measured by HPLC lipid profiling; PtdIns3P levels were variable across individual patients and correlated with presence of aberrant endolysosomal vacuoles.\",\n      \"method\": \"HPLC phosphoinositide profiling after myo-[2-3H]inositol labeling in patient fibroblasts, Western blot for FIG4 protein\",\n      \"journal\": \"Molecular neurobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct biochemical lipid measurement in patient primary cells, cohort of 13 patients vs 9 controls\",\n      \"pmids\": [\"31313076\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"VAC14 forms a star-shaped pentamer scaffold where two legs bind FIG4 (with one leg also occupied by PIKfyve); VAC14 oligomerization is critical for Fab1/PIKfyve function, PI(3,5)P2 generation, VAC14 localization, and formation of the PIKfyve-VAC14-FIG4 complex as assessed by pull-down assays; patient mutations at VAC14-VAC14 interfaces disrupt oligomerization and complex assembly.\",\n      \"method\": \"AlphaFold2 structural prediction, cryo-EM maps, pull-down assays in human VAC14 KO cells, fluorescence-detection size-exclusion chromatography, colocalization with VPS35 endosomes\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — structural prediction validated by cryo-EM plus biochemical pull-down and FSEC in KO cells, multiple orthogonal methods\",\n      \"pmids\": [\"40305106\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Proximity interactome (BioID) of VAC14 and FIG4 identified 89 high-confidence shared interactors; proximity ligation assays validated interaction between VAC14 and COPI subunit COPB1 and between VAC14 and the GTPase Arf1 (required for COPI assembly), suggesting the PIKfyve-VAC14-FIG4 complex interfaces with the COPI coat machinery at endosomes.\",\n      \"method\": \"BioID proximity labeling, proximity ligation assay, mass spectrometry\",\n      \"journal\": \"Journal of proteome research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — BioID is proximity labeling (not direct binding), validated by PLA for two interactions, single lab\",\n      \"pmids\": [\"34554760\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"PI(3,5)P2 inhibits the lysosomal chloride transporter ClC-7; loss of FIG4 (or VAC14) reduces PI(3,5)P2 and de-represses ClC-7, contributing to lysosomal swelling and hyperacidification. Knockout of CLCN7 (but not the related CLCN6) corrects lysosomal swelling and partially corrects lysosomal hyperacidification in FIG4-null cells; in vivo, dominant-negative CLCN7 expression improves growth, neurological function, and lifespan in Fig4 null mice by ~20%.\",\n      \"method\": \"CLCN7 and CLCN6 knockout in FIG4-null cell culture, lysosome size and pH measurements, transgenic dominant-negative CLCN7 in Fig4 null mice, survival and behavioral analysis\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis in both cell culture and in vivo mouse model, two independent genetic tools (KO and dominant-negative), specific control (CLCN6 KO negative result)\",\n      \"pmids\": [\"37363915\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"FIG4-regulated PI(3,5)P2 biosynthesis genetically interacts with the phosphoinositide kinase PIP4K2C: haploinsufficiency of Pip4k2c (which elevates PI(3,5)P2) rescues the neonatal lethality of Fig4 null mice and reduces lysosomal enlargement in Fig4 null cells, demonstrating that the opposing kinase PIP4K2C modulates the FIG4 pathway in vivo.\",\n      \"method\": \"Genetic compound mutant mice (Fig4-/-, Pip4k2c+/-), lysosome size measurement in fibroblasts, survival analysis\",\n      \"journal\": \"G3 (Bethesda, Md.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo genetic epistasis with survival and cellular phenotype readouts, single lab\",\n      \"pmids\": [\"36691351\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Fig4 mutants that fail to bind the Fab1-Vac14-Fig4 complex confer tolerance to rapamycin (TORC1 inhibitor) in yeast independent of Fig4 catalytic activity and Vac14 scaffolding, requiring instead the p21-activated kinase Ste20, demonstrating that Fig4 can modulate TORC1 signaling through a complex-independent, catalysis-independent interaction with unknown partners.\",\n      \"method\": \"Yeast genetics (point mutations, vac14Δ epistasis), rapamycin growth assays, temperature-shift experiments, kinase deletion (ste20Δ)\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis in yeast with multiple alleles and kinase requirements defined, single lab\",\n      \"pmids\": [\"40741910\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"FIG4 overexpression promotes LAMP2A-dependent autophagy-lysosomal degradation of IL-18 and enhances ubiquitination of IL-18, reducing its secretion; FIG4 thus functions as a regulator of IL-18 autophagic-lysosomal turnover in cancer cells.\",\n      \"method\": \"Overexpression and knockdown of FIG4, Western blot/ELISA for IL-18, lysosomal degradation assays, ubiquitination assays in triple-negative breast cancer cell lines\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Weak — single lab, single paper, cellular overexpression/knockdown, no in vitro reconstitution or structural validation\",\n      \"pmids\": [\"41577074\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FIG4 (SAC3/hSac3) is a magnesium-activated, PtdIns(3,5)P2-selective 5-phosphatase that forms an obligate trimeric complex with the kinase PIKfyve/FAB1 and the scaffold protein VAC14 (which forms a pentameric platform); within this complex FIG4 serves dual roles — catalytic turnover of PtdIns(3,5)P2 and a phosphatase-independent scaffolding/biosynthetic function that stabilizes PIKfyve activity and anchors the complex to endolysosomal membranes via PtdIns(3)P recognition. Loss of FIG4 reduces both PtdIns(3,5)P2 and PtdIns5P, impairing TRPML1-mediated lysosomal Ca2+ efflux, de-repressing the ClC-7 chloride transporter, and blocking lysosomal fission (through dynamin-1 downregulation), collectively causing accumulation of enlarged, hyperacidic lysosomes and neurodegeneration in neurons, Schwann cells, and oligodendrocytes.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"FIG4 is a magnesium-activated, PtdIns(3,5)P2-selective phosphoinositide 5-phosphatase that governs endolysosomal membrane homeostasis as an obligate component of the PIKfyve(Fab1)–VAC14–FIG4 complex [#0, #1, #3]. Originally defined in yeast as a Sac1-domain phosphatase that mediates turnover of PtdIns(3,5)P2 downstream of the Fab1 kinase [#0], FIG4 binds the scaffold VAC14 directly and depends on it for membrane localization and protein stability, while VAC14 oligomerizes into a star-shaped pentamer whose legs engage both FIG4 and PIKfyve to assemble the complex on PtdIns(3)P-bearing endolysosomal membranes [#1, #3, #16]. Despite acting catalytically to consume PtdIns(3,5)P2, FIG4 paradoxically supports its synthesis: loss of FIG4 lowers steady-state PtdIns(3,5)P2 and PtdIns5P, and catalytically dead FIG4 still rescues much of the phenotype, establishing a phosphatase-independent scaffolding/biosynthetic role in stabilizing PIKfyve activity in addition to its catalytic turnover function [#9, #12, #15]. The reduced PtdIns(3,5)P2 in FIG4-deficient cells impairs TRPML1-mediated lysosomal Ca2+ efflux and de-represses the lysosomal chloride transporter ClC-7, producing enlarged, hyperacidic lysosomes through a block in lysosomal fission tied to dynamin-1 downregulation; pharmacological TRPML1 activation or genetic suppression of CLCN7 corrects these defects [#11, #18]. In mammals FIG4 is required cell-autonomously in motor neurons and Schwann cells and non-cell-autonomously for oligodendrocyte myelination, and its loss causes spongiform neurodegeneration, axonal degeneration, and demyelination [#6, #8, #10]. Loss-of-function and destabilizing missense mutations such as FIG4-I41T, which disrupts VAC14 binding and triggers proteasomal degradation, cause Charcot-Marie-Tooth disease type 4J [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established FIG4's core biochemical identity by asking what enzyme controls PtdIns(3,5)P2 turnover, placing it as a phosphatase downstream of the Fab1 kinase.\",\n      \"evidence\": \"Genetic epistasis/suppressor screen and lipid phosphate measurement in yeast\",\n      \"pmids\": [\"11950935\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve substrate selectivity or whether FIG4 acts directly on the lipid in vitro\", \"Mammalian relevance not addressed\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Defined FIG4 as a magnesium-activated, PtdIns(3,5)P2-selective phosphatase and showed Vac14 anchors it to the vacuolar membrane, beginning to assemble the complex.\",\n      \"evidence\": \"In vitro phosphatase assay, GFP localization, and co-IP in yeast\",\n      \"pmids\": [\"14528018\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not include the kinase Fab1/PIKfyve in the architecture\", \"Structural basis of FIG4–Vac14 binding unknown\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Extended the yeast model to mammals, showing FIG4 is required for endosome-lysosome trafficking and that its loss causes neurodegeneration via vacuolar accumulation.\",\n      \"evidence\": \"Positional cloning, phosphoinositide measurement, and LAMP-2 imaging in the pale tremor mouse and patient cells\",\n      \"pmids\": [\"17572665\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cell-type basis of neurodegeneration not resolved\", \"Counterintuitive accumulation of PtdIns(3,5)P2 in some assays not yet reconciled with the phosphatase role\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Resolved the tripartite complex architecture by showing Fab1/PIKfyve joins Vac14 and Fig4 through its chaperonin-like domain, with FYVE-domain tethering to PtdIns(3)P, explaining dual synthesis/turnover.\",\n      \"evidence\": \"Reciprocal co-IP, domain-mapping pulldowns, and GFP localization in yeast\",\n      \"pmids\": [\"18653468\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and full structure not determined\", \"How a phosphatase and kinase coexist productively unexplained\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Connected lysosomal dysfunction to cellular consequence by showing vacuoles physically obstruct organelle trafficking and that neuronal death is non-apoptotic and non-ubiquitin-mediated.\",\n      \"evidence\": \"Time-lapse live imaging of patient fibroblasts and histology/EM of plt mouse neurons\",\n      \"pmids\": [\"18556664\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular cause of fission/trafficking block not identified\", \"Single-lab observation\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Established the disease mechanism for CMT4J by showing the I41T mutation disrupts VAC14 binding, destabilizing FIG4 and routing it to proteasomal degradation.\",\n      \"evidence\": \"Yeast two-hybrid, Western blot in VAC14-null tissue and patient fibroblasts, MG-132 rescue, transgenic mouse\",\n      \"pmids\": [\"21655088\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether residual FIG4 retains partial function in patients unclear\", \"Did not address phosphatase vs scaffolding contribution to disease\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Defined the cellular site of FIG4 requirement in the nervous system, showing neuronal expression is necessary and sufficient to prevent spongiform degeneration while astrocyte expression is not.\",\n      \"evidence\": \"Cell-type-specific transgenic rescue and conditional knockout with histology and survival analysis\",\n      \"pmids\": [\"22581779\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not isolate the molecular pathway downstream of neuronal FIG4 loss\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Revealed non-cell-autonomous neuron-to-glia signaling by showing neuronal Fig4 supports CNS myelination indirectly through oligodendrocyte maturation.\",\n      \"evidence\": \"NSE-Fig4 transgenic rescue, optic nerve EM, action potential recordings, OL-marker IHC\",\n      \"pmids\": [\"22131434\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Nature of the neuron-derived signal to oligodendrocytes unknown\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Showed neuron-type-specific lysosomal pathology, distinguishing sensory neuron membrane disruption from motor neuron lysosomal protein retention.\",\n      \"evidence\": \"EM and lysosomal-marker immunofluorescence (LAMP2, NPC1, M6PR) in plt mouse neurons\",\n      \"pmids\": [\"21410794\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Basis of neuron-type selectivity unexplained\", \"Single-lab descriptive study\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Uncovered a phosphatase-independent function by showing catalytic-dead FIG4 (and even the opposing Fab1 kinase) rescues lysosomal expansion, placing FIG4 action after endosome-lysosome fusion.\",\n      \"evidence\": \"Drosophila catalytic-dead rescue and genetic epistasis with Rab7/HOPS, LysoTracker\",\n      \"pmids\": [\"26662798\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of the scaffolding/biosynthetic function not isolated\", \"Mammalian confirmation pending at this stage\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Demonstrated cell-autonomous requirements in both motor neurons and Schwann cells, linking Schwann cell FIG4 to autophagy-dependent myelin biogenesis and remyelination.\",\n      \"evidence\": \"Cell-type-specific conditional knockouts with histology, EM, and nerve conduction\",\n      \"pmids\": [\"25187576\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define which lipid pool drives each cell-type phenotype\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Identified the fission defect mechanism, linking reduced PI(3,5)P2 to impaired TRPML1 Ca2+ efflux and dynamin-1 loss, with pharmacological TRPML1 activation rescuing lysosomal storage.\",\n      \"evidence\": \"Flow cytometry, Ca2+ assays, ML-SA1 rescue, dynamin-1 Western blot, ex vivo DRG\",\n      \"pmids\": [\"25926456\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How dynamin-1 expression is coupled to lysosomal Ca2+ not fully mapped\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Dissected the dual functions in mammals, showing catalytic-dead FIG4 rescues neonatal neurodegeneration (scaffolding role) but not long-term myelination/hydrocephalus (requiring catalysis).\",\n      \"evidence\": \"C486S active-site mutagenesis, fibroblast and neuronal transgenic rescue, histology, survival\",\n      \"pmids\": [\"26604144\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why catalysis is selectively required for long-term myelin maintenance unresolved\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identified TRPV4 as a FIG4-regulated membrane protein whose slowed turnover accumulates at the plasma membrane and contributes to neuronal death.\",\n      \"evidence\": \"TRPV4 IF/Western in patient fibroblasts, Fig4 siRNA in motor neurons, TRPV4 inhibition with viability assay\",\n      \"pmids\": [\"28859335\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"TRPV4 inhibition preserved viability without correcting trafficking, so the causal link is partial\", \"Single lab\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Established a life-long, tissue-differential requirement, showing adult PNS fibers degenerate without Fig4 while CNS fibers need it mainly for remyelination after injury.\",\n      \"evidence\": \"Inducible CAG-creER knockout, nerve histology, compound action potentials, lysolecithin lesion model\",\n      \"pmids\": [\"29688489\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why CNS adult fibers tolerate loss but PNS fibers do not unexplained\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Quantified the lipid consequence in patients, showing FIG4 deficiency reduces both PtdIns(3,5)P2 and PtdIns5P, with PtdIns3P variability tracking vacuolation.\",\n      \"evidence\": \"HPLC phosphoinositide profiling in 13 patient vs 9 control fibroblasts\",\n      \"pmids\": [\"31313076\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Source of inter-patient PtdIns3P variability not resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Solved the complex architecture, showing VAC14 forms a star-shaped pentamer whose legs bind FIG4 and PIKfyve, and that oligomerization is required for PI(3,5)P2 generation.\",\n      \"evidence\": \"AlphaFold2/cryo-EM, pull-downs in VAC14 KO cells, FSEC, VPS35 colocalization\",\n      \"pmids\": [\"40305106\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"High-resolution structure of FIG4 within the assembly still incomplete\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Mapped the complex's broader interactome, linking the PIKfyve-VAC14-FIG4 complex to the COPI coat machinery (COPB1, Arf1) at endosomes.\",\n      \"evidence\": \"BioID proximity labeling and proximity ligation assay validation\",\n      \"pmids\": [\"34554760\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"BioID detects proximity, not direct binding\", \"Functional consequence of COPI interface untested\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified ClC-7 as a key effector, showing PI(3,5)P2 inhibits the transporter and that suppressing CLCN7 corrects lysosomal swelling and extends Fig4-null mouse lifespan.\",\n      \"evidence\": \"CLCN7/CLCN6 KO in FIG4-null cells, lysosome size/pH assays, dominant-negative CLCN7 in mice\",\n      \"pmids\": [\"37363915\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Only partial correction of hyperacidification, indicating additional effectors\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined an opposing-kinase modulator, showing Pip4k2c haploinsufficiency elevates PI(3,5)P2 and rescues Fig4-null lethality and lysosomal enlargement.\",\n      \"evidence\": \"Fig4-/- Pip4k2c+/- compound mutant mice, fibroblast lysosome measurement, survival\",\n      \"pmids\": [\"36691351\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of PIP4K2C control over the PI(3,5)P2 pool not detailed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Uncovered a complex- and catalysis-independent role in TORC1 signaling, where Fig4 mutants confer rapamycin tolerance through the kinase Ste20.\",\n      \"evidence\": \"Yeast point-mutant genetics, vac14Δ/ste20Δ epistasis, rapamycin growth assays\",\n      \"pmids\": [\"40741910\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The unknown partners mediating this function are unidentified\", \"Mammalian relevance untested\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Extended FIG4 into cancer cell biology, showing FIG4 overexpression drives LAMP2A-dependent autophagic-lysosomal degradation and ubiquitination of IL-18.\",\n      \"evidence\": \"FIG4 overexpression/knockdown, IL-18 Western/ELISA, degradation and ubiquitination assays in TNBC lines\",\n      \"pmids\": [\"41577074\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No reconstitution or structural validation\", \"Direct vs indirect effect on IL-18 turnover unresolved\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How FIG4's catalytic and scaffolding functions are differentially deployed across cell types and how the complex selectively maintains PI(3,5)P2 pools for distinct effectors (TRPML1, ClC-7) remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No high-resolution structure of FIG4 within the assembled complex\", \"Mechanism coupling lipid changes to dynamin-1 and TRPV4 turnover incompletely defined\", \"Complex-independent FIG4 functions (TORC1, IL-18) mechanistically unmapped\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [3, 9, 12, 16]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [1, 3, 15]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [2, 7, 11, 18]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [3, 16, 17]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [13]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [2, 4, 10]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [2, 4, 11]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [10, 21]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [6, 8, 10]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [20]}\n    ],\n    \"complexes\": [\"PIKfyve-VAC14-FIG4 (PAS) complex\"],\n    \"partners\": [\"VAC14\", \"PIKFYVE\", \"COPB1\", \"ARF1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":6,"faith_total":6,"faith_pct":100.0}}