{"gene":"LGI3","run_date":"2026-04-28T18:30:27","timeline":{"discoveries":[{"year":2010,"finding":"LGI3 interacts with flotillin-1 (Flo1) and stabilizes it reciprocally; knockdown of the LGI3/Flo1 complex redirects amyloid precursor protein (APP) trafficking to late endosomes and disrupts exosome formation, indicating LGI3 is involved in endocytosis and intracellular vesicular transport.","method":"Co-immunoprecipitation, RNA interference (siRNA knockdown), Western blot","journal":"Neuroreport","confidence":"Medium","confidence_rationale":"Tier 2–3 — reciprocal stabilization and trafficking phenotype shown by RNAi and Co-IP, single lab","pmids":["20461023"],"is_preprint":false},{"year":2007,"finding":"LGI3 localizes to plasma membranes and nuclei of neural cells; in aged monkey brains it accumulates at plasma membranes, co-localizes with endocytosis-associated proteins and lipid raft markers, and co-localizes with Aβ in astrocytes, suggesting a role in membrane-associated endocytic processes.","method":"Immunohistochemistry, subcellular fractionation, Western blot, double immunohistochemistry","journal":"Cellular and molecular neurobiology","confidence":"Medium","confidence_rationale":"Tier 2 — direct localization with functional context via fractionation and co-localization, single lab","pmids":["17786549"],"is_preprint":false},{"year":2007,"finding":"Aβ upregulates LGI3 expression in rat astrocyte cultures, and LGI3 co-localizes with Aβ at plasma membranes and at sites of internalized Aβ, implicating LGI3 in the astroglial response to Aβ.","method":"RT-PCR, Western blot, immunocytochemistry","journal":"Cellular and molecular neurobiology","confidence":"Medium","confidence_rationale":"Tier 3 — co-localization and expression induction, single lab, no functional rescue","pmids":["17387609"],"is_preprint":false},{"year":2012,"finding":"UVB-induced LGI3 secretion from human keratinocytes promotes cell survival by stimulating Akt phosphorylation, leading to MDM2 phosphorylation and subsequent p53 degradation.","method":"ELISA, cell viability assay, Western blot (phospho-Akt, phospho-MDM2, p53 levels), recombinant LGI3 treatment","journal":"Experimental dermatology","confidence":"Medium","confidence_rationale":"Tier 2–3 — pathway placement via pharmacological inhibition and Western blot, single lab","pmids":["22741557"],"is_preprint":false},{"year":2019,"finding":"LPS triggers LGI3 secretion from keratinocytes via a TRIF-dependent NF-κB pathway; activated NF-κB binds the LGI3 promoter and drives LGI3 production, and secreted LGI3 associates with ADAM22 as its receptor in keratinocytes.","method":"ELISA, co-immunoprecipitation, flow cytometry, immunocytochemistry, promoter analysis, selective COX-2 inhibitor (NS-398) blockade","journal":"Cytokine","confidence":"Medium","confidence_rationale":"Tier 2–3 — NF-κB/promoter binding and Co-IP of LGI3-ADAM22, multiple orthogonal methods, single lab","pmids":["31627033"],"is_preprint":false},{"year":2018,"finding":"LGI3 promotes keratinocyte differentiation through selective activation of the PI3K/Akt pathway; LGI3-knockout mice show reduced involucrin expression, and PI3K inhibitor LY294002 blocks LGI3-induced differentiation markers.","method":"LGI3-knockout mouse model, siRNA knockdown, Western blot (Akt, ERK, p38, JNK), pharmacological inhibition (LY294002)","journal":"Experimental dermatology","confidence":"Medium","confidence_rationale":"Tier 2 — genetic KO plus pharmacological pathway dissection, single lab","pmids":["30091803"],"is_preprint":false},{"year":2022,"finding":"LGI3 restores keratinocyte migration in high-glucose environments by activating Akt, leading to β-catenin accumulation via phosphorylation of FOXO1 and FAK; PI3K inhibition with LY294002 abolishes this effect.","method":"Wound closure assay, siRNA knockdown, Western blot (Akt, FOXO1, FAK, β-catenin, GSK3β, JNK, ERK, p38), pharmacological inhibition","journal":"Die Pharmazie","confidence":"Medium","confidence_rationale":"Tier 2–3 — pathway dissection with inhibitor and KD, single lab","pmids":["35751164"],"is_preprint":false},{"year":2023,"finding":"LGI3 (together with LGI2) binds axonal ADAM23 and is essential for the accumulation and stability of juxtaparanodal Kv1 channel complexes in myelinated axons; disruption of LGI2/LGI3–ADAM23 interaction abolishes Kv1 clustering and alters the refractory period, enabling high-frequency burst firing.","method":"Genetic mouse models (ADAM23 and LGI knockout), immunohistochemistry, electrophysiology (refractory period measurement)","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 — genetic epistasis in vivo with defined electrophysiological phenotype, replicated in two independent studies","pmids":["36828548"],"is_preprint":false},{"year":2024,"finding":"LGI3 is uniquely secreted from oligodendrocytes and enriched at juxtaparanodes; proteomic analysis using Lgi3 knockin mice shows LGI3 uses ADAM23 as its receptor and selectively co-assembles with Kv1 channels; loss of Lgi3 disrupts juxtaparanodal clustering of ADAM23 and Kv1 channels and suppresses Kv1-channel-mediated short-term synaptic plasticity.","method":"Epitope-tagged knockin mice, proteomics (AP-MS), immunohistochemistry, electrophysiology (short-term plasticity), LGI3 missense variant secretion assay","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1–2 — in vivo proteomics, genetic KO, electrophysiology, and variant functional assay in single study; replicated by independent group","pmids":["38194969"],"is_preprint":false},{"year":2025,"finding":"LGI3 interacts with KV1.5 channels in human atrial tissue and heterologous cells, impairs KV1.5/KVβ association, partially reverses KVβ-induced N-type inactivation, and reduces IKur amplitude; LGI3 also reduces KV1.5 membrane expression.","method":"Co-immunoprecipitation, patch-clamp electrophysiology, surface expression assay, AAV-mediated cardiac gene transfer mouse model, immunolocalization","journal":"Cardiovascular research","confidence":"High","confidence_rationale":"Tier 1–2 — electrophysiology plus Co-IP plus in vivo mouse model, multiple orthogonal methods","pmids":["41854369"],"is_preprint":false},{"year":2025,"finding":"LGI3 is a direct transcriptional target of TFE3 fusion protein in renal cell carcinoma; LGI3 interacts with GEMIN6, inhibits its ubiquitin-mediated degradation, and thereby promotes AURKB mRNA maturation, driving tumor progression.","method":"ChIP (TFE3 binding to LGI3 promoter), co-immunoprecipitation (LGI3-GEMIN6), ubiquitination assay, siRNA/overexpression, organoid growth assay","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2–3 — ChIP, Co-IP, and ubiquitination assay in single study, single lab","pmids":["40849584"],"is_preprint":false}],"current_model":"LGI3 is a secreted leucine-rich repeat protein that in the nervous system is released from oligodendrocytes, binds ADAM23 on axons, and organizes juxtaparanodal Kv1 potassium channel clustering to regulate axonal refractory period and short-term synaptic plasticity; in the heart it is a component of the KV1.5 channelosome where it impairs KV1.5–KVβ interaction to reduce IKur; in keratinocytes it acts as an autocrine/paracrine cytokine that signals through ADAM22 and activates PI3K/Akt to promote survival, differentiation, and migration; and in renal cell carcinoma it stabilizes GEMIN6 by blocking its ubiquitination, thereby enhancing AURKB expression and tumor progression."},"narrative":{"teleology":[{"year":2007,"claim":"Initial localization studies established that LGI3 resides at plasma membranes and in nuclei of neural cells and co-localizes with endocytic and lipid raft markers, placing LGI3 in a membrane-associated signaling context before any functional role was known.","evidence":"Immunohistochemistry, subcellular fractionation, and co-localization in aged monkey brain and rat astrocyte cultures","pmids":["17786549","17387609"],"confidence":"Medium","gaps":["No functional assay for endocytic activity","Co-localization with Aβ does not demonstrate direct interaction","Role in astrocytes versus neurons not resolved"]},{"year":2010,"claim":"Discovery that LGI3 interacts with and reciprocally stabilizes flotillin-1 revealed a role in intracellular vesicular trafficking, as loss of the LGI3/flotillin-1 complex redirected APP to late endosomes and disrupted exosome formation.","evidence":"Co-immunoprecipitation and siRNA knockdown with Western blot in neural cell lines","pmids":["20461023"],"confidence":"Medium","gaps":["Single-lab observation without independent replication","Mechanism of stabilization (direct binding site) unknown","Relevance to in vivo APP processing not tested"]},{"year":2012,"claim":"Identification of LGI3 as a UVB-induced secreted factor from keratinocytes that activates Akt→MDM2→p53 degradation established LGI3 as an autocrine survival cytokine outside the nervous system.","evidence":"ELISA for secreted LGI3, recombinant protein treatment, phospho-Akt and p53 Western blot in human keratinocytes","pmids":["22741557"],"confidence":"Medium","gaps":["Receptor identity was not determined in this study","In vivo relevance to skin UV protection not shown"]},{"year":2018,"claim":"Using LGI3-knockout mice and pharmacological inhibition, LGI3 was shown to selectively activate PI3K/Akt (not ERK, p38, or JNK) to drive keratinocyte differentiation, providing genetic validation of the pathway.","evidence":"LGI3-knockout mouse, siRNA, LY294002 inhibition, involucrin expression in skin","pmids":["30091803"],"confidence":"Medium","gaps":["Single-lab genetic model","Downstream transcriptional targets of Akt in differentiation not mapped"]},{"year":2019,"claim":"The receptor for secreted LGI3 in keratinocytes was identified as ADAM22, and LGI3 transcription was shown to be driven by NF-κB via TRIF-dependent signaling, completing the stimulus–secretion–receptor circuit.","evidence":"Co-immunoprecipitation of LGI3–ADAM22, NF-κB ChIP on LGI3 promoter, LPS-stimulated keratinocytes","pmids":["31627033"],"confidence":"Medium","gaps":["ADAM22 interaction shown by Co-IP without domain mapping","Whether ADAM22 is the sole receptor in skin not tested"]},{"year":2022,"claim":"LGI3 was found to rescue high-glucose-impaired keratinocyte migration by activating Akt→FOXO1/FAK→β-catenin, extending its PI3K/Akt signaling role to wound healing contexts.","evidence":"Wound closure assay, siRNA knockdown, pharmacological inhibition with LY294002","pmids":["35751164"],"confidence":"Medium","gaps":["In vivo diabetic wound healing model not performed","Single-lab study"]},{"year":2023,"claim":"Genetic studies in mice demonstrated that LGI3 (with LGI2) binds ADAM23 and is essential for juxtaparanodal Kv1 channel clustering; loss of LGI3–ADAM23 interaction abolished Kv1 accumulation and altered the refractory period, enabling pathological high-frequency firing.","evidence":"Genetic knockout/knockin mouse models, immunohistochemistry, electrophysiology (refractory period)","pmids":["36828548"],"confidence":"High","gaps":["Relative contributions of LGI2 versus LGI3 not fully delineated","Structural basis of LGI3–ADAM23 binding unknown"]},{"year":2024,"claim":"In vivo proteomics using epitope-tagged Lgi3 knockin mice established that LGI3 is uniquely secreted from oligodendrocytes and selectively co-assembles with Kv1 channels via ADAM23, and that its loss suppresses Kv1-channel-mediated short-term synaptic plasticity.","evidence":"AP-MS proteomics from knockin mice, LGI3-null electrophysiology (short-term plasticity), missense variant secretion assay","pmids":["38194969"],"confidence":"High","gaps":["Whether LGI3 acts on unmyelinated axons is unknown","Mechanism by which LGI3 stabilizes the Kv1–ADAM23 complex at the molecular level not resolved"]},{"year":2025,"claim":"LGI3 was identified as a component of the cardiac KV1.5 channelosome that impairs KV1.5–KVβ association, partially reverses N-type inactivation, and reduces IKur amplitude and KV1.5 surface expression, establishing a cardiac electrophysiological function.","evidence":"Co-immunoprecipitation in human atrial tissue, patch-clamp electrophysiology, AAV-mediated cardiac gene transfer in mice","pmids":["41854369"],"confidence":"High","gaps":["Whether LGI3 modulation of KV1.5 is relevant to atrial fibrillation in vivo not tested","Mechanism of reduced surface expression (trafficking vs. degradation) not distinguished"]},{"year":2025,"claim":"In TFE3-fusion renal cell carcinoma, LGI3 was identified as a direct TFE3 transcriptional target that stabilizes GEMIN6 by blocking its ubiquitination, promoting AURKB mRNA maturation and tumor progression — the first oncogenic mechanism described for LGI3.","evidence":"ChIP, co-immunoprecipitation (LGI3–GEMIN6), ubiquitination assay, organoid growth assay","pmids":["40849584"],"confidence":"Medium","gaps":["Single-lab study; not independently replicated","Whether LGI3 stabilizes GEMIN6 through direct ubiquitin competition or indirect E3-ligase modulation is unknown","Generalizability to non-TFE3-fusion cancers not addressed"]},{"year":null,"claim":"No structural model of LGI3 in complex with any receptor (ADAM22, ADAM23, KV1.5) exists, and whether LGI3's diverse tissue-specific functions share a common molecular mechanism of action through metalloprotease-family receptors remains an open question.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal or cryo-EM structure of LGI3 or LGI3–receptor complex","Mechanism by which LGI3 discriminates between ADAM22 and ADAM23 in different tissues is unknown","In vivo physiological roles in tissues beyond brain, skin, and heart have not been explored"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[7,8,9]},{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[3,4,5,6]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[3,4,8]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,7,9]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[0,1]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[3,5,6]},{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[7,8]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[10]}],"complexes":["Kv1 juxtaparanodal complex","KV1.5 channelosome"],"partners":["ADAM23","ADAM22","KCNA5","FLOT1","GEMIN6","KCNAB1"],"other_free_text":[]},"mechanistic_narrative":"LGI3 is a secreted leucine-rich repeat protein that organizes ion channel complexes and activates PI3K/Akt signaling across multiple tissue contexts. In myelinated axons, LGI3 is released from oligodendrocytes, binds the receptor ADAM23, and is essential for juxtaparanodal clustering of Kv1 potassium channels, thereby controlling the axonal refractory period and short-term synaptic plasticity [PMID:36828548, PMID:38194969]. In keratinocytes, LGI3 acts as an autocrine/paracrine cytokine that signals through ADAM22 and activates PI3K/Akt to promote cell survival (via MDM2-mediated p53 degradation), differentiation, and migration [PMID:22741557, PMID:30091803, PMID:31627033]. In the heart, LGI3 is a component of the KV1.5 channelosome, where it impairs KV1.5–KVβ interaction and reduces the ultra-rapid delayed rectifier current IKur [PMID:41854369]; in renal cell carcinoma, it stabilizes GEMIN6 by blocking its ubiquitination to promote AURKB expression and tumor growth [PMID:40849584]."},"prefetch_data":{"uniprot":{"accession":"Q8N145","full_name":"Leucine-rich repeat LGI family member 3","aliases":["LGI1-like protein 4","Leucine-rich glioma-inactivated protein 3"],"length_aa":548,"mass_kda":61.7,"function":"May participate in the regulation of neuronal exocytosis","subcellular_location":"Secreted; Cytoplasmic vesicle, secretory vesicle, synaptic vesicle; Synapse, synaptosome; Cell projection, axon","url":"https://www.uniprot.org/uniprotkb/Q8N145/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/LGI3","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/LGI3","total_profiled":1310},"omim":[{"mim_id":"620007","title":"INTELLECTUAL DEVELOPMENTAL DISORDER WITH MUSCLE TONE ABNORMALITIES AND DISTAL SKELETAL DEFECTS; IDDMDS","url":"https://www.omim.org/entry/620007"},{"mim_id":"608303","title":"LEUCINE-RICH GENE, GLIOMA-INACTIVATED, 4; LGI4","url":"https://www.omim.org/entry/608303"},{"mim_id":"608302","title":"LEUCINE-RICH GENE, GLIOMA-INACTIVATED, 3; LGI3","url":"https://www.omim.org/entry/608302"},{"mim_id":"608301","title":"LEUCINE-RICH GENE, GLIOMA-INACTIVATED, 2; LGI2","url":"https://www.omim.org/entry/608301"},{"mim_id":"600512","title":"EPILEPSY, FAMILIAL TEMPORAL LOBE, 1; ETL1","url":"https://www.omim.org/entry/600512"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":95.3}],"url":"https://www.proteinatlas.org/search/LGI3"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q8N145","domains":[{"cath_id":"3.80.10.10","chopping":"42-216","consensus_level":"medium","plddt":94.1055,"start":42,"end":216},{"cath_id":"-","chopping":"219-234_440-548","consensus_level":"medium","plddt":95.3982,"start":219,"end":548}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N145","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N145-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N145-F1-predicted_aligned_error_v6.png","plddt_mean":91.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=LGI3","jax_strain_url":"https://www.jax.org/strain/search?query=LGI3"},"sequence":{"accession":"Q8N145","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8N145.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8N145/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N145"}},"corpus_meta":[{"pmid":"16545924","id":"PMC_16545924","title":"Mouse LGI3 gene: expression in brain and promoter analysis.","date":"2006","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/16545924","citation_count":30,"is_preprint":false},{"pmid":"22741557","id":"PMC_22741557","title":"Ultraviolet B-induced LGI3 secretion protects human keratinocytes.","date":"2012","source":"Experimental dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/22741557","citation_count":19,"is_preprint":false},{"pmid":"20461023","id":"PMC_20461023","title":"LGI3 interacts with flotillin-1 to mediate APP trafficking and exosome formation.","date":"2010","source":"Neuroreport","url":"https://pubmed.ncbi.nlm.nih.gov/20461023","citation_count":17,"is_preprint":false},{"pmid":"30091803","id":"PMC_30091803","title":"LGI3 promotes human keratinocyte differentiation via the Akt pathway.","date":"2018","source":"Experimental dermatology","url":"https://pubmed.ncbi.nlm.nih.gov/30091803","citation_count":16,"is_preprint":false},{"pmid":"17387609","id":"PMC_17387609","title":"Abeta upregulates and colocalizes with LGI3 in cultured rat astrocytes.","date":"2007","source":"Cellular and molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/17387609","citation_count":14,"is_preprint":false},{"pmid":"36828548","id":"PMC_36828548","title":"LGI3/2-ADAM23 interactions cluster Kv1 channels in myelinated axons to regulate refractory period.","date":"2023","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/36828548","citation_count":14,"is_preprint":false},{"pmid":"17786549","id":"PMC_17786549","title":"Immunohistochemical and biochemical analyses of LGI3 in monkey brain: LGI3 accumulates in aged monkey brains.","date":"2007","source":"Cellular and molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/17786549","citation_count":13,"is_preprint":false},{"pmid":"38194969","id":"PMC_38194969","title":"Oligodendrocyte-derived LGI3 and its receptor ADAM23 organize juxtaparanodal Kv1 channel clustering for short-term synaptic plasticity.","date":"2024","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/38194969","citation_count":10,"is_preprint":false},{"pmid":"31627033","id":"PMC_31627033","title":"LGI3 is secreted and binds to ADAM22 via TRIF-dependent NF-κB pathway in response to LPS in human keratinocytes.","date":"2019","source":"Cytokine","url":"https://pubmed.ncbi.nlm.nih.gov/31627033","citation_count":6,"is_preprint":false},{"pmid":"35751164","id":"PMC_35751164","title":"LGI3 promotes human keratinocyte migration in high-glucose environments by increasing the expression of β-catenin.","date":"2022","source":"Die Pharmazie","url":"https://pubmed.ncbi.nlm.nih.gov/35751164","citation_count":4,"is_preprint":false},{"pmid":"32785038","id":"PMC_32785038","title":"The Suppressive Effect of Leucine-Rich Glioma Inactivated 3 (LGI3) Peptide on Impaired Skin Barrier Function in a Murine Model Atopic Dermatitis.","date":"2020","source":"Pharmaceutics","url":"https://pubmed.ncbi.nlm.nih.gov/32785038","citation_count":2,"is_preprint":false},{"pmid":"40849584","id":"PMC_40849584","title":"LGI3 promotes the progression of TFE3-rearranged renal cell carcinoma through GEMIN6/AURKB axis.","date":"2025","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/40849584","citation_count":0,"is_preprint":false},{"pmid":"41854369","id":"PMC_41854369","title":"Lgi3-4 proteins modulate the KV1.5 channelosome and are potential therapeutic targets for atrial fibrillation.","date":"2026","source":"Cardiovascular research","url":"https://pubmed.ncbi.nlm.nih.gov/41854369","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.10.03.616587","title":"Novel insights into<i>I</i><sub>Kur</sub>modulation by Lgi3-4: Implications in atrial fibrillation","date":"2024-10-06","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.03.616587","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8510,"output_tokens":2637,"usd":0.032543},"stage2":{"model":"claude-opus-4-6","input_tokens":6027,"output_tokens":2786,"usd":0.149677},"total_usd":0.18222,"stage1_batch_id":"msgbatch_01Mgbec4vM6c9vXht7JVJzss","stage2_batch_id":"msgbatch_01JkuuH5RB2BdJNsgnhjbC6s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"LGI3 interacts with flotillin-1 (Flo1) and stabilizes it reciprocally; knockdown of the LGI3/Flo1 complex redirects amyloid precursor protein (APP) trafficking to late endosomes and disrupts exosome formation, indicating LGI3 is involved in endocytosis and intracellular vesicular transport.\",\n      \"method\": \"Co-immunoprecipitation, RNA interference (siRNA knockdown), Western blot\",\n      \"journal\": \"Neuroreport\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — reciprocal stabilization and trafficking phenotype shown by RNAi and Co-IP, single lab\",\n      \"pmids\": [\"20461023\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"LGI3 localizes to plasma membranes and nuclei of neural cells; in aged monkey brains it accumulates at plasma membranes, co-localizes with endocytosis-associated proteins and lipid raft markers, and co-localizes with Aβ in astrocytes, suggesting a role in membrane-associated endocytic processes.\",\n      \"method\": \"Immunohistochemistry, subcellular fractionation, Western blot, double immunohistochemistry\",\n      \"journal\": \"Cellular and molecular neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct localization with functional context via fractionation and co-localization, single lab\",\n      \"pmids\": [\"17786549\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Aβ upregulates LGI3 expression in rat astrocyte cultures, and LGI3 co-localizes with Aβ at plasma membranes and at sites of internalized Aβ, implicating LGI3 in the astroglial response to Aβ.\",\n      \"method\": \"RT-PCR, Western blot, immunocytochemistry\",\n      \"journal\": \"Cellular and molecular neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — co-localization and expression induction, single lab, no functional rescue\",\n      \"pmids\": [\"17387609\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"UVB-induced LGI3 secretion from human keratinocytes promotes cell survival by stimulating Akt phosphorylation, leading to MDM2 phosphorylation and subsequent p53 degradation.\",\n      \"method\": \"ELISA, cell viability assay, Western blot (phospho-Akt, phospho-MDM2, p53 levels), recombinant LGI3 treatment\",\n      \"journal\": \"Experimental dermatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — pathway placement via pharmacological inhibition and Western blot, single lab\",\n      \"pmids\": [\"22741557\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"LPS triggers LGI3 secretion from keratinocytes via a TRIF-dependent NF-κB pathway; activated NF-κB binds the LGI3 promoter and drives LGI3 production, and secreted LGI3 associates with ADAM22 as its receptor in keratinocytes.\",\n      \"method\": \"ELISA, co-immunoprecipitation, flow cytometry, immunocytochemistry, promoter analysis, selective COX-2 inhibitor (NS-398) blockade\",\n      \"journal\": \"Cytokine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — NF-κB/promoter binding and Co-IP of LGI3-ADAM22, multiple orthogonal methods, single lab\",\n      \"pmids\": [\"31627033\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"LGI3 promotes keratinocyte differentiation through selective activation of the PI3K/Akt pathway; LGI3-knockout mice show reduced involucrin expression, and PI3K inhibitor LY294002 blocks LGI3-induced differentiation markers.\",\n      \"method\": \"LGI3-knockout mouse model, siRNA knockdown, Western blot (Akt, ERK, p38, JNK), pharmacological inhibition (LY294002)\",\n      \"journal\": \"Experimental dermatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO plus pharmacological pathway dissection, single lab\",\n      \"pmids\": [\"30091803\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"LGI3 restores keratinocyte migration in high-glucose environments by activating Akt, leading to β-catenin accumulation via phosphorylation of FOXO1 and FAK; PI3K inhibition with LY294002 abolishes this effect.\",\n      \"method\": \"Wound closure assay, siRNA knockdown, Western blot (Akt, FOXO1, FAK, β-catenin, GSK3β, JNK, ERK, p38), pharmacological inhibition\",\n      \"journal\": \"Die Pharmazie\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — pathway dissection with inhibitor and KD, single lab\",\n      \"pmids\": [\"35751164\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"LGI3 (together with LGI2) binds axonal ADAM23 and is essential for the accumulation and stability of juxtaparanodal Kv1 channel complexes in myelinated axons; disruption of LGI2/LGI3–ADAM23 interaction abolishes Kv1 clustering and alters the refractory period, enabling high-frequency burst firing.\",\n      \"method\": \"Genetic mouse models (ADAM23 and LGI knockout), immunohistochemistry, electrophysiology (refractory period measurement)\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis in vivo with defined electrophysiological phenotype, replicated in two independent studies\",\n      \"pmids\": [\"36828548\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"LGI3 is uniquely secreted from oligodendrocytes and enriched at juxtaparanodes; proteomic analysis using Lgi3 knockin mice shows LGI3 uses ADAM23 as its receptor and selectively co-assembles with Kv1 channels; loss of Lgi3 disrupts juxtaparanodal clustering of ADAM23 and Kv1 channels and suppresses Kv1-channel-mediated short-term synaptic plasticity.\",\n      \"method\": \"Epitope-tagged knockin mice, proteomics (AP-MS), immunohistochemistry, electrophysiology (short-term plasticity), LGI3 missense variant secretion assay\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — in vivo proteomics, genetic KO, electrophysiology, and variant functional assay in single study; replicated by independent group\",\n      \"pmids\": [\"38194969\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"LGI3 interacts with KV1.5 channels in human atrial tissue and heterologous cells, impairs KV1.5/KVβ association, partially reverses KVβ-induced N-type inactivation, and reduces IKur amplitude; LGI3 also reduces KV1.5 membrane expression.\",\n      \"method\": \"Co-immunoprecipitation, patch-clamp electrophysiology, surface expression assay, AAV-mediated cardiac gene transfer mouse model, immunolocalization\",\n      \"journal\": \"Cardiovascular research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — electrophysiology plus Co-IP plus in vivo mouse model, multiple orthogonal methods\",\n      \"pmids\": [\"41854369\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"LGI3 is a direct transcriptional target of TFE3 fusion protein in renal cell carcinoma; LGI3 interacts with GEMIN6, inhibits its ubiquitin-mediated degradation, and thereby promotes AURKB mRNA maturation, driving tumor progression.\",\n      \"method\": \"ChIP (TFE3 binding to LGI3 promoter), co-immunoprecipitation (LGI3-GEMIN6), ubiquitination assay, siRNA/overexpression, organoid growth assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — ChIP, Co-IP, and ubiquitination assay in single study, single lab\",\n      \"pmids\": [\"40849584\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"LGI3 is a secreted leucine-rich repeat protein that in the nervous system is released from oligodendrocytes, binds ADAM23 on axons, and organizes juxtaparanodal Kv1 potassium channel clustering to regulate axonal refractory period and short-term synaptic plasticity; in the heart it is a component of the KV1.5 channelosome where it impairs KV1.5–KVβ interaction to reduce IKur; in keratinocytes it acts as an autocrine/paracrine cytokine that signals through ADAM22 and activates PI3K/Akt to promote survival, differentiation, and migration; and in renal cell carcinoma it stabilizes GEMIN6 by blocking its ubiquitination, thereby enhancing AURKB expression and tumor progression.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"LGI3 is a secreted leucine-rich repeat protein that organizes ion channel complexes and activates PI3K/Akt signaling across multiple tissue contexts. In myelinated axons, LGI3 is released from oligodendrocytes, binds the receptor ADAM23, and is essential for juxtaparanodal clustering of Kv1 potassium channels, thereby controlling the axonal refractory period and short-term synaptic plasticity [PMID:36828548, PMID:38194969]. In keratinocytes, LGI3 acts as an autocrine/paracrine cytokine that signals through ADAM22 and activates PI3K/Akt to promote cell survival (via MDM2-mediated p53 degradation), differentiation, and migration [PMID:22741557, PMID:30091803, PMID:31627033]. In the heart, LGI3 is a component of the KV1.5 channelosome, where it impairs KV1.5–KVβ interaction and reduces the ultra-rapid delayed rectifier current IKur [PMID:41854369]; in renal cell carcinoma, it stabilizes GEMIN6 by blocking its ubiquitination to promote AURKB expression and tumor growth [PMID:40849584].\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"Initial localization studies established that LGI3 resides at plasma membranes and in nuclei of neural cells and co-localizes with endocytic and lipid raft markers, placing LGI3 in a membrane-associated signaling context before any functional role was known.\",\n      \"evidence\": \"Immunohistochemistry, subcellular fractionation, and co-localization in aged monkey brain and rat astrocyte cultures\",\n      \"pmids\": [\"17786549\", \"17387609\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional assay for endocytic activity\", \"Co-localization with Aβ does not demonstrate direct interaction\", \"Role in astrocytes versus neurons not resolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Discovery that LGI3 interacts with and reciprocally stabilizes flotillin-1 revealed a role in intracellular vesicular trafficking, as loss of the LGI3/flotillin-1 complex redirected APP to late endosomes and disrupted exosome formation.\",\n      \"evidence\": \"Co-immunoprecipitation and siRNA knockdown with Western blot in neural cell lines\",\n      \"pmids\": [\"20461023\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab observation without independent replication\", \"Mechanism of stabilization (direct binding site) unknown\", \"Relevance to in vivo APP processing not tested\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identification of LGI3 as a UVB-induced secreted factor from keratinocytes that activates Akt→MDM2→p53 degradation established LGI3 as an autocrine survival cytokine outside the nervous system.\",\n      \"evidence\": \"ELISA for secreted LGI3, recombinant protein treatment, phospho-Akt and p53 Western blot in human keratinocytes\",\n      \"pmids\": [\"22741557\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor identity was not determined in this study\", \"In vivo relevance to skin UV protection not shown\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Using LGI3-knockout mice and pharmacological inhibition, LGI3 was shown to selectively activate PI3K/Akt (not ERK, p38, or JNK) to drive keratinocyte differentiation, providing genetic validation of the pathway.\",\n      \"evidence\": \"LGI3-knockout mouse, siRNA, LY294002 inhibition, involucrin expression in skin\",\n      \"pmids\": [\"30091803\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab genetic model\", \"Downstream transcriptional targets of Akt in differentiation not mapped\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"The receptor for secreted LGI3 in keratinocytes was identified as ADAM22, and LGI3 transcription was shown to be driven by NF-κB via TRIF-dependent signaling, completing the stimulus–secretion–receptor circuit.\",\n      \"evidence\": \"Co-immunoprecipitation of LGI3–ADAM22, NF-κB ChIP on LGI3 promoter, LPS-stimulated keratinocytes\",\n      \"pmids\": [\"31627033\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"ADAM22 interaction shown by Co-IP without domain mapping\", \"Whether ADAM22 is the sole receptor in skin not tested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"LGI3 was found to rescue high-glucose-impaired keratinocyte migration by activating Akt→FOXO1/FAK→β-catenin, extending its PI3K/Akt signaling role to wound healing contexts.\",\n      \"evidence\": \"Wound closure assay, siRNA knockdown, pharmacological inhibition with LY294002\",\n      \"pmids\": [\"35751164\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo diabetic wound healing model not performed\", \"Single-lab study\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Genetic studies in mice demonstrated that LGI3 (with LGI2) binds ADAM23 and is essential for juxtaparanodal Kv1 channel clustering; loss of LGI3–ADAM23 interaction abolished Kv1 accumulation and altered the refractory period, enabling pathological high-frequency firing.\",\n      \"evidence\": \"Genetic knockout/knockin mouse models, immunohistochemistry, electrophysiology (refractory period)\",\n      \"pmids\": [\"36828548\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contributions of LGI2 versus LGI3 not fully delineated\", \"Structural basis of LGI3–ADAM23 binding unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"In vivo proteomics using epitope-tagged Lgi3 knockin mice established that LGI3 is uniquely secreted from oligodendrocytes and selectively co-assembles with Kv1 channels via ADAM23, and that its loss suppresses Kv1-channel-mediated short-term synaptic plasticity.\",\n      \"evidence\": \"AP-MS proteomics from knockin mice, LGI3-null electrophysiology (short-term plasticity), missense variant secretion assay\",\n      \"pmids\": [\"38194969\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether LGI3 acts on unmyelinated axons is unknown\", \"Mechanism by which LGI3 stabilizes the Kv1–ADAM23 complex at the molecular level not resolved\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"LGI3 was identified as a component of the cardiac KV1.5 channelosome that impairs KV1.5–KVβ association, partially reverses N-type inactivation, and reduces IKur amplitude and KV1.5 surface expression, establishing a cardiac electrophysiological function.\",\n      \"evidence\": \"Co-immunoprecipitation in human atrial tissue, patch-clamp electrophysiology, AAV-mediated cardiac gene transfer in mice\",\n      \"pmids\": [\"41854369\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether LGI3 modulation of KV1.5 is relevant to atrial fibrillation in vivo not tested\", \"Mechanism of reduced surface expression (trafficking vs. degradation) not distinguished\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"In TFE3-fusion renal cell carcinoma, LGI3 was identified as a direct TFE3 transcriptional target that stabilizes GEMIN6 by blocking its ubiquitination, promoting AURKB mRNA maturation and tumor progression — the first oncogenic mechanism described for LGI3.\",\n      \"evidence\": \"ChIP, co-immunoprecipitation (LGI3–GEMIN6), ubiquitination assay, organoid growth assay\",\n      \"pmids\": [\"40849584\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab study; not independently replicated\", \"Whether LGI3 stabilizes GEMIN6 through direct ubiquitin competition or indirect E3-ligase modulation is unknown\", \"Generalizability to non-TFE3-fusion cancers not addressed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"No structural model of LGI3 in complex with any receptor (ADAM22, ADAM23, KV1.5) exists, and whether LGI3's diverse tissue-specific functions share a common molecular mechanism of action through metalloprotease-family receptors remains an open question.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal or cryo-EM structure of LGI3 or LGI3–receptor complex\", \"Mechanism by which LGI3 discriminates between ADAM22 and ADAM23 in different tissues is unknown\", \"In vivo physiological roles in tissues beyond brain, skin, and heart have not been explored\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [7, 8, 9]},\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [3, 4, 5, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [3, 4, 8]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 7, 9]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [3, 5, 6]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [7, 8]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [10]}\n    ],\n    \"complexes\": [\n      \"Kv1 juxtaparanodal complex\",\n      \"KV1.5 channelosome\"\n    ],\n    \"partners\": [\n      \"ADAM23\",\n      \"ADAM22\",\n      \"KCNA5\",\n      \"FLOT1\",\n      \"GEMIN6\",\n      \"KCNAB1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}