{"gene":"CADM4","run_date":"2026-04-28T17:28:52","timeline":{"discoveries":[{"year":2007,"finding":"Necl4/CADM4 is the main Necl expressed by myelinating Schwann cells along the internodes, where it binds in trans to axonal Necl1/CADM3 to mediate Schwann cell adhesion. Disruption of this interaction using soluble extracellular domains or dominant-negative Necl4 expression in Schwann cells inhibits myelination.","method":"Co-immunoprecipitation, dominant-negative overexpression, soluble domain competition assay, in vitro myelination assay","journal":"Nature neuroscience","confidence":"High","confidence_rationale":"Tier 2 — reciprocal binding assay, dominant-negative functional rescue, replicated across multiple experimental approaches in a highly-cited paper","pmids":["17558405"],"is_preprint":false},{"year":2013,"finding":"Genetic deletion of Cadm4 specifically in Schwann cells causes focal hypermyelination (tomacula and myelin outfoldings), abnormal axon-glial contact, redistribution of ion channels along the axon, impaired motor function, and slower nerve conduction velocity. The cytoplasmic domain of Cadm4 is required, as transgenic mice expressing a dominant-negative Cadm4 lacking this domain phenocopy the knockout.","method":"Conditional knockout mouse (Cre-lox), dominant-negative transgenic mouse, electron microscopy, nerve conduction velocity measurement, behavioral assays","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — multiple genetic mouse models with defined cellular phenotypes and functional readouts","pmids":["23825401"],"is_preprint":false},{"year":2001,"finding":"CADM4 (TSLL2) encodes a transmembrane immunoglobulin superfamily protein with three extracellular Ig-like domains and a cytoplasmic domain structurally homologous to TSLC1/CADM1, forming a unique subfamily. Its cytoplasmic domain shares significant similarity with TSLC1, suggesting functional importance of this domain.","method":"Molecular cloning, sequence analysis, Northern blot expression profiling","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 3 — structural/sequence characterization without functional mutagenesis","pmids":["11536053"],"is_preprint":false},{"year":2006,"finding":"CADM4 (TSLL2) forms homodimers and induces Ca2+/Mg2+-independent cell aggregation when overexpressed in MDCK cells, indicating homophilic trans-interaction. It localizes to lateral membranes in polarized epithelial cells and suppresses tumor formation in nude mice when introduced into a prostate cancer cell line.","method":"Cell aggregation assay, confocal microscopy, subcutaneous tumor xenograft, overexpression in MDCK and PPC-1 cells","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 — in vitro adhesion assay plus in vivo tumor suppression, single lab","pmids":["16261159"],"is_preprint":false},{"year":2011,"finding":"CADM4 associates with the actin-binding protein 4.1B (DAL-1) in normal human kidney proximal tubules, as demonstrated by immunoprecipitation. Introduction of CADM4 into an RCC cell line (786-O) suppresses tumor formation in nude mice, supporting a tumor suppressor function.","method":"Co-immunoprecipitation, Western blotting, nude mouse xenograft tumor suppression assay, immunohistochemistry","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 — reciprocal Co-IP plus in vivo functional assay, single lab","pmids":["21544807"],"is_preprint":false},{"year":2013,"finding":"Necl-4/CADM4 interacts in cis with ErbB3 via their extracellular regions, recruits PTPN13, and inhibits heregulin-induced ErbB2/ErbB3 signaling. Additionally, Necl-4 interacts in cis with integrin α6β4 and inhibits phorbol ester-induced hemidesmosome disassembly.","method":"Co-immunoprecipitation, overexpression/knockdown, signaling assays (phosphorylation of ErbB2/ErbB3), hemidesmosome disassembly assay","journal":"Genes to cells","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP with defined signaling pathway readout, single lab","pmids":["23611113"],"is_preprint":false},{"year":2015,"finding":"In confluent vascular endothelial cells, Necl-4/CADM4 is upregulated and localizes at cell-cell contact sites where it cis-interacts with VEGFR2, inhibiting VEGFR2 tyrosine-phosphorylation through PTPN13 to reduce cell movement and proliferation. In sparse cells, Necl-4 accumulates at leading edges and inhibits ROCK via PTPN13, facilitating Rac1 activation and ERK1/2 activation to enhance VEGF-induced cell movement and proliferation.","method":"Co-immunoprecipitation, knockdown (siRNA), live cell imaging, phosphorylation assays, Rac1 activation assay","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP plus signaling pathway readouts with knockdown, single lab","pmids":["25893857"],"is_preprint":false},{"year":2017,"finding":"Necl-4/CADM4 knockdown inhibits VEGF-induced phosphorylation of PLCγ, c-Raf, MEK, and ERK without affecting VEGFR2 phosphorylation or internalization, placing Necl-4 as a regulator of the PLCγ-c-Raf-MEK-ERK pathway downstream of or parallel to VEGFR2. This effect is independent of PTPN13 and ROCK.","method":"siRNA knockdown, phosphorylation assays, VEGFR2 internalization assay","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — pharmacological and genetic epistasis placing Necl-4 in a defined signaling cascade, single lab","pmids":["28601637"],"is_preprint":false},{"year":2018,"finding":"Increased expression of a membrane-bound extracellular domain of Cadm4 (Cadm4dCT) in oligodendrocytes produces numerous axoglial contact sites that fail to elongate into mature myelin. Transgenic mice expressing Cadm4dCT are hypomyelinated and show myelination of neuronal somata. These abnormalities require specific neuron-glial interaction dependent on axonal Cadm4 receptors.","method":"Transgenic mouse model, in vitro oligodendrocyte-neuron co-culture, nanofiber culture, genetics (neurons from receptor-knockout mice)","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 — multiple genetic and in vitro models with defined cellular phenotypes, replicated in vivo and in vitro","pmids":["30551998"],"is_preprint":false},{"year":2018,"finding":"Necl-4/Cadm4's cytoplasmic terminal region (CTR) binds the first PDZ domain of Par-3, recruiting Par-3 to the adaxonal membrane of myelinating Schwann cells at sites of Necl-4/Necl-1 interaction. Knockdown of Necl-4 perturbs Par-3 localization to the inner Schwann cell membrane.","method":"Unbiased PDZ-domain proteomic screen, co-immunoprecipitation from Schwann cell lysates, co-localization by immunofluorescence, siRNA knockdown in myelinating co-cultures","journal":"Glia","confidence":"High","confidence_rationale":"Tier 2 — unbiased proteomic screen confirmed by Co-IP, co-localization, and functional knockdown with defined localization readout","pmids":["30585357"],"is_preprint":false},{"year":2022,"finding":"Cadm4 forms a membrane skeletal complex with Mpp6 (Pals2), protein band 4.1G (Epb41l2), and Lin7 in Schmidt-Lanterman incisures (SLIs) of PNS myelin. In FA2H-deficient mice, this complex is enriched in aged sciatic nerve myelin alongside increased SLI number.","method":"Mass spectrometry-based proteomics of purified myelin, electron microscopy to count SLIs","journal":"Molecular neurobiology","confidence":"Medium","confidence_rationale":"Tier 3 — proteomic identification of complex in purified myelin, single study without direct interaction validation","pmids":["35445918"],"is_preprint":false},{"year":2024,"finding":"CADM4 undergoes palmitoylation at cysteine-347 (C347), catalyzed by ZDHHC3, which is required for stable plasma membrane localization. A C347A knock-in mutation blocks palmitoylation, causes CADM4 internalization and degradation, and produces severe CNS myelin abnormalities. ZDHHC3 knockout phenocopies this, reducing Cadm4 palmitoylation and causing CNS myelination defects. Altered Cadm4 palmitoylation also impairs oligodendrocyte differentiation via the WNT-β-Catenin pathway.","method":"Site-directed mutagenesis, knock-in mouse model, ZDHHC3 knockout mouse, palmitoylation assay, plasma membrane fractionation, WNT-β-Catenin pathway analysis, electrophysiology, behavioral testing","journal":"Signal transduction and targeted therapy","confidence":"High","confidence_rationale":"Tier 1 — site-directed mutagenesis of palmitoylation site combined with two independent genetic mouse models and multiple orthogonal readouts","pmids":["39327467"],"is_preprint":false},{"year":2025,"finding":"Necl-4/CADM4 is expressed in GABAergic inhibitory neurons and localizes at GABAergic synapses on inhibitory neurons. Necl-4 knockout increases GABAergic synapse density and synaptic molecules on inhibitory neurons via ErbB4 activation, enhances GABAergic synaptic currents, induces high-frequency firing, and causes excitotoxicity-mediated neuronal death in the hippocampus.","method":"Genetic knockout mouse, immunofluorescence, electrophysiology (mIPSC recording), ErbB4 pathway analysis, hippocampal neuron culture","journal":"Molecular neurobiology","confidence":"Medium","confidence_rationale":"Tier 2 — knockout with electrophysiology and defined pathway (ErbB4), single lab","pmids":["40728771"],"is_preprint":false},{"year":2014,"finding":"In zebrafish, cadm4 restricts the size of the cardiac outflow tract (OFT) by limiting the production of OFT progenitor cells from the second heart field and the duration of their accumulation at the arterial pole. Knockdown causes OFT expansion; overexpression causes OFT reduction.","method":"Morpholino knockdown, mRNA overexpression, confocal live imaging, cell lineage tracing in zebrafish","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function and gain-of-function with defined progenitor cell phenotype in zebrafish ortholog","pmids":["24813897"],"is_preprint":false}],"current_model":"CADM4 (Necl-4/SynCAM4) is a transmembrane immunoglobulin superfamily cell adhesion molecule that mediates axon-glia adhesion in both PNS and CNS: in PNS Schwann cells it binds axonal CADM3 in trans, recruits the polarity protein Par-3 via its PDZ-binding cytoplasmic domain, and requires ZDHHC3-mediated palmitoylation at C347 for stable plasma membrane localization; loss of Cadm4 or its palmitoylation causes hypermyelination, myelin outfoldings, and ion channel redistribution, while in the CNS excessive Cadm4-mediated adhesion blocks myelin elongation. Beyond myelination, CADM4 cis-interacts with VEGFR2, ErbB3, and integrin α6β4 on cell surfaces, modulating VEGF-PLCγ-ERK and ErbB2/ErbB3 signaling through PTPN13 to regulate contact inhibition and tumor suppression, and in GABAergic neurons it restrains ErbB4-dependent synaptic strengthening to prevent excitotoxic neuronal death."},"narrative":{"teleology":[{"year":2001,"claim":"Identification of CADM4 (TSLL2) as a new immunoglobulin superfamily member structurally related to CADM1/TSLC1 established it as part of a discrete adhesion molecule subfamily, raising the question of whether it shares tumor-suppressor and adhesion functions.","evidence":"Molecular cloning and sequence analysis with Northern blot expression profiling","pmids":["11536053"],"confidence":"Medium","gaps":["No functional data beyond structural prediction","Expression pattern not resolved at protein level","No binding partners identified"]},{"year":2006,"claim":"Demonstration that CADM4 mediates homophilic cell aggregation and suppresses tumor growth in xenografts established it as both an adhesion molecule and a candidate tumor suppressor, but left the molecular mechanism of tumor suppression unresolved.","evidence":"Cell aggregation assay in MDCK cells and subcutaneous xenograft of prostate cancer cells in nude mice","pmids":["16261159"],"confidence":"Medium","gaps":["Tumor suppression mechanism not defined","Homophilic vs. heterophilic binding hierarchy unclear","Endogenous relevance in non-cancer tissues not tested"]},{"year":2007,"claim":"Identification of CADM4 as the principal Necl on myelinating Schwann cells and its heterophilic trans-binding to axonal CADM3 established CADM4 as the key glial adhesion molecule at the axon-Schwann cell interface, explaining how myelination initiation depends on axon-glial recognition.","evidence":"Co-immunoprecipitation, dominant-negative overexpression, soluble domain competition, and in vitro myelination assays","pmids":["17558405"],"confidence":"High","gaps":["Intracellular signaling downstream of CADM4 in Schwann cells not identified","In vivo genetic validation lacking at this point","Whether CADM4 functions similarly in CNS oligodendrocytes unknown"]},{"year":2011,"claim":"Association of CADM4 with the actin-binding protein 4.1B and tumor suppression in renal cell carcinoma linked CADM4's cytoplasmic domain to cytoskeletal scaffolding, but the mechanistic basis of growth inhibition remained open.","evidence":"Co-immunoprecipitation from kidney tissue and nude mouse xenograft tumor suppression assay","pmids":["21544807"],"confidence":"Medium","gaps":["Direct vs. indirect nature of 4.1B interaction not resolved","No signaling pathway analysis downstream of 4.1B","Relevance to endogenous kidney physiology untested in knockout"]},{"year":2013,"claim":"Two advances resolved CADM4's in vivo myelination role and its receptor tyrosine kinase regulatory mechanism: Schwann cell-specific Cadm4 knockout produced focal hypermyelination with myelin outfoldings and ion channel mislocalization, proving CADM4 constrains myelin growth via its cytoplasmic domain; concurrently, identification of cis-interactions with ErbB3 and integrin α6β4 plus recruitment of PTPN13 to inhibit ErbB2/ErbB3 signaling provided the first defined signaling pathway for CADM4-mediated contact inhibition.","evidence":"Conditional knockout and dominant-negative transgenic mice with EM, electrophysiology, and behavioral assays; Co-IP with signaling phosphorylation readouts and hemidesmosome assays in epithelial cells","pmids":["23825401","23611113"],"confidence":"High","gaps":["How cytoplasmic domain restrains myelin growth mechanistically unresolved","Whether PTPN13-ErbB3 axis operates in Schwann cells unknown","Direct structural basis of cis-interaction with RTKs not determined"]},{"year":2014,"claim":"Zebrafish cadm4 was shown to restrict cardiac outflow tract size by limiting second heart field progenitor production, revealing a developmental role outside the nervous system.","evidence":"Morpholino knockdown and mRNA overexpression with confocal live imaging and lineage tracing in zebrafish","pmids":["24813897"],"confidence":"Medium","gaps":["Mechanism by which cadm4 limits progenitor production not defined","Not validated in mammalian cardiac development","Morpholino-based; genetic mutant confirmation lacking"]},{"year":2015,"claim":"Discovery that CADM4 cis-interacts with VEGFR2 and context-dependently either inhibits (confluent cells via PTPN13) or promotes (sparse cells via Rac1) VEGF signaling explained how a single adhesion molecule can exert opposing effects on endothelial behavior depending on cell density.","evidence":"Co-IP, siRNA knockdown, live imaging, phosphorylation and Rac1 activation assays in endothelial cells","pmids":["25893857"],"confidence":"Medium","gaps":["In vivo vascular relevance not tested","Switch mechanism between inhibitory and activating modes not molecularly defined","Whether CADM4 directly bridges VEGFR2 and PTPN13 or acts indirectly unclear"]},{"year":2017,"claim":"Epistasis experiments showed CADM4 is required for VEGF-induced PLCγ–Raf–MEK–ERK signaling independently of PTPN13 and ROCK, establishing a second, phosphatase-independent signaling arm through which CADM4 regulates endothelial proliferation.","evidence":"siRNA knockdown with phosphorylation cascade analysis and VEGFR2 internalization assay","pmids":["28601637"],"confidence":"Medium","gaps":["Direct molecular target linking CADM4 to PLCγ not identified","Functional consequence for angiogenesis in vivo untested","Single lab observation"]},{"year":2018,"claim":"Two studies resolved CADM4's CNS myelination role and its mechanism for organizing Schwann cell polarity: excess Cadm4 extracellular domain in oligodendrocytes created abundant but non-elongating contacts causing hypomyelination, showing that regulated adhesion-to-wrapping transition is essential; separately, CADM4's cytoplasmic tail was found to bind Par-3's first PDZ domain, recruiting it to the adaxonal Schwann cell membrane at sites of CADM3 engagement.","evidence":"Transgenic mouse and oligodendrocyte-neuron co-cultures; unbiased PDZ-domain proteomic screen with Co-IP, co-localization, and siRNA knockdown in myelinating co-cultures","pmids":["30551998","30585357"],"confidence":"High","gaps":["Whether Par-3 recruitment mediates the myelin-restraining function remains untested genetically","Axonal receptors required for oligodendrocyte Cadm4 signaling only partially identified","Downstream effectors of Par-3 at the adaxonal membrane not defined"]},{"year":2022,"claim":"Proteomic identification of a CADM4–Mpp6–4.1G–Lin7 complex in Schmidt-Lanterman incisures placed CADM4 within a defined membrane skeleton at non-compact myelin domains, suggesting a structural scaffolding role in myelin maintenance.","evidence":"Mass spectrometry of purified PNS myelin with electron microscopy quantification of SLIs in FA2H-deficient mice","pmids":["35445918"],"confidence":"Medium","gaps":["Direct binary interactions within the complex not validated","Functional consequence of disrupting this complex at SLIs unknown","Observed enrichment in disease model; normal-state stoichiometry not established"]},{"year":2024,"claim":"Identification of ZDHHC3-mediated palmitoylation at C347 as essential for CADM4 plasma membrane retention resolved how post-translational modification controls CADM4 surface expression; C347A knock-in and ZDHHC3 knockout mice both exhibit severe CNS dysmyelination and impaired oligodendrocyte differentiation via aberrant WNT–β-catenin signaling.","evidence":"Site-directed mutagenesis, C347A knock-in mouse, ZDHHC3 knockout mouse, palmitoylation assay, membrane fractionation, WNT pathway analysis, electrophysiology, behavioral testing","pmids":["39327467"],"confidence":"High","gaps":["Whether palmitoylation similarly controls PNS myelination functions not fully explored","How loss of membrane CADM4 activates WNT–β-catenin mechanistically unresolved","Other potential palmitoylation sites and additional palmitoyl transferases not excluded"]},{"year":2025,"claim":"Discovery that CADM4 at GABAergic synapses restrains ErbB4-dependent synapse formation on inhibitory neurons revealed a synaptic function beyond myelination: Cadm4 knockout increases GABAergic synapse density, enhances inhibitory currents, and causes excitotoxic neuronal death.","evidence":"Knockout mouse with immunofluorescence, mIPSC electrophysiology, ErbB4 pathway analysis, and hippocampal neuron culture","pmids":["40728771"],"confidence":"Medium","gaps":["Whether CADM4 directly binds ErbB4 or acts via intermediate partners not determined","Cell-type-specific rescue experiments not performed","Behavioral consequences of synaptic phenotype not fully characterized"]},{"year":null,"claim":"Key unresolved questions include the structural basis of CADM4's cis-interactions with multiple receptor tyrosine kinases, how its cytoplasmic domain coordinates Par-3 recruitment with myelin growth restraint, and whether its myelination and tumor-suppressive functions share a common signaling logic.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal or cryo-EM structure of CADM4 or its complexes","Genetic epistasis between Par-3 and CADM4 in myelination not tested in vivo","Unified signaling model across myelination, vascular, and tumor-suppressor contexts lacking"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[0,1,3,8]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[5,6,7,12]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[5,6,9]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,3,6,9,11]}],"pathway":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0]}],"complexes":["CADM4-Mpp6-4.1G-Lin7 membrane skeleton"],"partners":["CADM3","PTPN13","PARD3","EPB41L2","EPB41L3","ERBB3","KDR","ZDHHC3"],"other_free_text":[]},"mechanistic_narrative":"CADM4 (Necl-4/SynCAM4) is an immunoglobulin superfamily cell adhesion molecule that functions as a central mediator of axon-glia interactions during myelination and as a modulator of receptor tyrosine kinase signaling in epithelia and endothelia. In the PNS, CADM4 is expressed by myelinating Schwann cells at internodes where it binds axonal CADM3 in trans, recruits the polarity protein Par-3 via its cytoplasmic PDZ-binding domain, and requires ZDHHC3-mediated palmitoylation at C347 for stable plasma membrane retention; loss of Cadm4 or its palmitoylation causes focal hypermyelination, myelin outfoldings, and ion channel redistribution in the PNS, while in the CNS excess Cadm4-mediated adhesion blocks myelin sheet elongation and C347A knock-in mice exhibit severe CNS dysmyelination [PMID:17558405, PMID:23825401, PMID:30551998, PMID:30585357, PMID:39327467]. CADM4 also cis-interacts with VEGFR2, ErbB3, and integrin α6β4, recruiting the phosphatase PTPN13 to inhibit ErbB2/ErbB3 and VEGFR2 signaling and independently regulating the PLCγ–Raf–MEK–ERK cascade downstream of VEGF, thereby contributing to contact inhibition of growth and tumor suppression [PMID:23611113, PMID:25893857, PMID:28601637, PMID:16261159]. In GABAergic neurons, CADM4 restrains ErbB4-dependent synapse formation; its loss increases GABAergic synapse density, enhances inhibitory synaptic currents, and triggers excitotoxic neuronal death [PMID:40728771]."},"prefetch_data":{"uniprot":{"accession":"Q8NFZ8","full_name":"Cell adhesion molecule 4","aliases":["Immunoglobulin superfamily member 4C","IgSF4C","Nectin-like protein 4","NECL-4","TSLC1-like protein 2"],"length_aa":388,"mass_kda":42.8,"function":"Involved in the cell-cell adhesion. Has calcium- and magnesium-independent cell-cell adhesion activity. May have tumor-suppressor activity","subcellular_location":"Membrane","url":"https://www.uniprot.org/uniprotkb/Q8NFZ8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CADM4","classification":"Not Classified","n_dependent_lines":204,"n_total_lines":1208,"dependency_fraction":0.16887417218543047},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CADM4","total_profiled":1310},"omim":[{"mim_id":"619519","title":"CHARCOT-MARIE-TOOTH DISEASE, AXONAL, TYPE 2FF; CMT2FF","url":"https://www.omim.org/entry/619519"},{"mim_id":"609744","title":"CELL ADHESION MOLECULE 4; CADM4","url":"https://www.omim.org/entry/609744"},{"mim_id":"609743","title":"CELL ADHESION MOLECULE 3; CADM3","url":"https://www.omim.org/entry/609743"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":203.4}],"url":"https://www.proteinatlas.org/search/CADM4"},"hgnc":{"alias_symbol":["TSLL2","Necl-4","SynCAM4"],"prev_symbol":["IGSF4C"]},"alphafold":{"accession":"Q8NFZ8","domains":[{"cath_id":"2.60.40.10","chopping":"25-120","consensus_level":"high","plddt":94.7828,"start":25,"end":120},{"cath_id":"2.60.40.10","chopping":"127-220","consensus_level":"high","plddt":96.4123,"start":127,"end":220},{"cath_id":"2.60.40.10","chopping":"222-308","consensus_level":"high","plddt":94.0337,"start":222,"end":308}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NFZ8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NFZ8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NFZ8-F1-predicted_aligned_error_v6.png","plddt_mean":85.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CADM4","jax_strain_url":"https://www.jax.org/strain/search?query=CADM4"},"sequence":{"accession":"Q8NFZ8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8NFZ8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8NFZ8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NFZ8"}},"corpus_meta":[{"pmid":"17558405","id":"PMC_17558405","title":"A central role for Necl4 (SynCAM4) in Schwann cell-axon interaction and myelination.","date":"2007","source":"Nature neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/17558405","citation_count":159,"is_preprint":false},{"pmid":"23825401","id":"PMC_23825401","title":"Genetic deletion of Cadm4 results in myelin abnormalities resembling Charcot-Marie-Tooth neuropathy.","date":"2013","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/23825401","citation_count":64,"is_preprint":false},{"pmid":"11536053","id":"PMC_11536053","title":"Isolation of the TSLL1 and TSLL2 genes, members of the tumor suppressor TSLC1 gene family encoding transmembrane proteins.","date":"2001","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/11536053","citation_count":61,"is_preprint":false},{"pmid":"30551998","id":"PMC_30551998","title":"Axoglial Adhesion by Cadm4 Regulates CNS Myelination.","date":"2018","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/30551998","citation_count":55,"is_preprint":false},{"pmid":"21544807","id":"PMC_21544807","title":"Aberrations of a cell adhesion molecule CADM4 in renal clear cell carcinoma.","date":"2011","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/21544807","citation_count":53,"is_preprint":false},{"pmid":"16261159","id":"PMC_16261159","title":"Cell adhesion and prostate tumor-suppressor activity of TSLL2/IGSF4C, an immunoglobulin superfamily molecule homologous to TSLC1/IGSF4.","date":"2006","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/16261159","citation_count":46,"is_preprint":false},{"pmid":"24813897","id":"PMC_24813897","title":"Cadm4 restricts the production of cardiac outflow tract progenitor cells.","date":"2014","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/24813897","citation_count":36,"is_preprint":false},{"pmid":"29434950","id":"PMC_29434950","title":"Decreased expression of CADM1 and CADM4 are associated with advanced stage breast cancer.","date":"2017","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/29434950","citation_count":24,"is_preprint":false},{"pmid":"23700466","id":"PMC_23700466","title":"Necl-4/SynCAM-4 is expressed in myelinating oligodendrocytes but not required for axonal myelination.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23700466","citation_count":23,"is_preprint":false},{"pmid":"25893857","id":"PMC_25893857","title":"The Cell Adhesion Molecule Necl-4/CADM4 Serves as a Novel Regulator for Contact Inhibition of Cell Movement and Proliferation.","date":"2015","source":"PloS 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membrane.","date":"2018","source":"Glia","url":"https://pubmed.ncbi.nlm.nih.gov/30585357","citation_count":15,"is_preprint":false},{"pmid":"22718847","id":"PMC_22718847","title":"Clinicopathological significance of CADM4 expression, and its correlation with expression of E-cadherin and Ki-67 in colorectal adenocarcinomas.","date":"2012","source":"Journal of clinical pathology","url":"https://pubmed.ncbi.nlm.nih.gov/22718847","citation_count":15,"is_preprint":false},{"pmid":"14659875","id":"PMC_14659875","title":"Isolation of the mouse Tsll1 and Tsll2 genes, orthologues of the human TSLC1-like genes 1 and 2 (TSLL1 and TSLL2).","date":"2003","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/14659875","citation_count":12,"is_preprint":false},{"pmid":"27980052","id":"PMC_27980052","title":"Clinicopathological significance of Necl-4 expression in pancreatic ductal adenocarcinoma.","date":"2016","source":"Journal of clinical pathology","url":"https://pubmed.ncbi.nlm.nih.gov/27980052","citation_count":10,"is_preprint":false},{"pmid":"23559354","id":"PMC_23559354","title":"Clinicopathological significance of CADM4 expression in invasive ductal carcinoma of the breast.","date":"2013","source":"Journal of clinical pathology","url":"https://pubmed.ncbi.nlm.nih.gov/23559354","citation_count":8,"is_preprint":false},{"pmid":"28601637","id":"PMC_28601637","title":"Necl-4 enhances the PLCγ-c-Raf-MEK-ERK pathway without affecting internalization of VEGFR2.","date":"2017","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/28601637","citation_count":7,"is_preprint":false},{"pmid":"28561015","id":"PMC_28561015","title":"Necl 4 and RNase 5 Are Important Biomarkers for Gastric and Colon Adenocarcinomas.","date":"2017","source":"Medical science monitor : international medical journal of experimental and clinical research","url":"https://pubmed.ncbi.nlm.nih.gov/28561015","citation_count":4,"is_preprint":false},{"pmid":"35445918","id":"PMC_35445918","title":"Age-Dependent Increase in Schmidt-Lanterman Incisures and a Cadm4-Associated Membrane Skeletal Complex in Fatty Acid 2-hydroxylase Deficient Mice: a Mouse Model of Spastic Paraplegia SPG35.","date":"2022","source":"Molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/35445918","citation_count":3,"is_preprint":false},{"pmid":"40728771","id":"PMC_40728771","title":"Necl-4/CADM4 regulates GABAergic synaptic strength on GABAergic inhibitory neurons via ErbB4 activation and prevents neuronal impairments.","date":"2025","source":"Molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/40728771","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11889,"output_tokens":3640,"usd":0.045134},"stage2":{"model":"claude-opus-4-6","input_tokens":7048,"output_tokens":7229,"usd":0.323947},"total_usd":0.369081,"stage1_batch_id":"msgbatch_011kfMfE81o6CTcyhVUqumuW","stage2_batch_id":"msgbatch_01DTputS6WNkH745x1nVSoBo","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2007,\n      \"finding\": \"Necl4/CADM4 is the main Necl expressed by myelinating Schwann cells along the internodes, where it binds in trans to axonal Necl1/CADM3 to mediate Schwann cell adhesion. Disruption of this interaction using soluble extracellular domains or dominant-negative Necl4 expression in Schwann cells inhibits myelination.\",\n      \"method\": \"Co-immunoprecipitation, dominant-negative overexpression, soluble domain competition assay, in vitro myelination assay\",\n      \"journal\": \"Nature neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal binding assay, dominant-negative functional rescue, replicated across multiple experimental approaches in a highly-cited paper\",\n      \"pmids\": [\"17558405\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Genetic deletion of Cadm4 specifically in Schwann cells causes focal hypermyelination (tomacula and myelin outfoldings), abnormal axon-glial contact, redistribution of ion channels along the axon, impaired motor function, and slower nerve conduction velocity. The cytoplasmic domain of Cadm4 is required, as transgenic mice expressing a dominant-negative Cadm4 lacking this domain phenocopy the knockout.\",\n      \"method\": \"Conditional knockout mouse (Cre-lox), dominant-negative transgenic mouse, electron microscopy, nerve conduction velocity measurement, behavioral assays\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple genetic mouse models with defined cellular phenotypes and functional readouts\",\n      \"pmids\": [\"23825401\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"CADM4 (TSLL2) encodes a transmembrane immunoglobulin superfamily protein with three extracellular Ig-like domains and a cytoplasmic domain structurally homologous to TSLC1/CADM1, forming a unique subfamily. Its cytoplasmic domain shares significant similarity with TSLC1, suggesting functional importance of this domain.\",\n      \"method\": \"Molecular cloning, sequence analysis, Northern blot expression profiling\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — structural/sequence characterization without functional mutagenesis\",\n      \"pmids\": [\"11536053\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"CADM4 (TSLL2) forms homodimers and induces Ca2+/Mg2+-independent cell aggregation when overexpressed in MDCK cells, indicating homophilic trans-interaction. It localizes to lateral membranes in polarized epithelial cells and suppresses tumor formation in nude mice when introduced into a prostate cancer cell line.\",\n      \"method\": \"Cell aggregation assay, confocal microscopy, subcutaneous tumor xenograft, overexpression in MDCK and PPC-1 cells\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vitro adhesion assay plus in vivo tumor suppression, single lab\",\n      \"pmids\": [\"16261159\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"CADM4 associates with the actin-binding protein 4.1B (DAL-1) in normal human kidney proximal tubules, as demonstrated by immunoprecipitation. Introduction of CADM4 into an RCC cell line (786-O) suppresses tumor formation in nude mice, supporting a tumor suppressor function.\",\n      \"method\": \"Co-immunoprecipitation, Western blotting, nude mouse xenograft tumor suppression assay, immunohistochemistry\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP plus in vivo functional assay, single lab\",\n      \"pmids\": [\"21544807\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Necl-4/CADM4 interacts in cis with ErbB3 via their extracellular regions, recruits PTPN13, and inhibits heregulin-induced ErbB2/ErbB3 signaling. Additionally, Necl-4 interacts in cis with integrin α6β4 and inhibits phorbol ester-induced hemidesmosome disassembly.\",\n      \"method\": \"Co-immunoprecipitation, overexpression/knockdown, signaling assays (phosphorylation of ErbB2/ErbB3), hemidesmosome disassembly assay\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP with defined signaling pathway readout, single lab\",\n      \"pmids\": [\"23611113\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"In confluent vascular endothelial cells, Necl-4/CADM4 is upregulated and localizes at cell-cell contact sites where it cis-interacts with VEGFR2, inhibiting VEGFR2 tyrosine-phosphorylation through PTPN13 to reduce cell movement and proliferation. In sparse cells, Necl-4 accumulates at leading edges and inhibits ROCK via PTPN13, facilitating Rac1 activation and ERK1/2 activation to enhance VEGF-induced cell movement and proliferation.\",\n      \"method\": \"Co-immunoprecipitation, knockdown (siRNA), live cell imaging, phosphorylation assays, Rac1 activation assay\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP plus signaling pathway readouts with knockdown, single lab\",\n      \"pmids\": [\"25893857\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Necl-4/CADM4 knockdown inhibits VEGF-induced phosphorylation of PLCγ, c-Raf, MEK, and ERK without affecting VEGFR2 phosphorylation or internalization, placing Necl-4 as a regulator of the PLCγ-c-Raf-MEK-ERK pathway downstream of or parallel to VEGFR2. This effect is independent of PTPN13 and ROCK.\",\n      \"method\": \"siRNA knockdown, phosphorylation assays, VEGFR2 internalization assay\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological and genetic epistasis placing Necl-4 in a defined signaling cascade, single lab\",\n      \"pmids\": [\"28601637\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Increased expression of a membrane-bound extracellular domain of Cadm4 (Cadm4dCT) in oligodendrocytes produces numerous axoglial contact sites that fail to elongate into mature myelin. Transgenic mice expressing Cadm4dCT are hypomyelinated and show myelination of neuronal somata. These abnormalities require specific neuron-glial interaction dependent on axonal Cadm4 receptors.\",\n      \"method\": \"Transgenic mouse model, in vitro oligodendrocyte-neuron co-culture, nanofiber culture, genetics (neurons from receptor-knockout mice)\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple genetic and in vitro models with defined cellular phenotypes, replicated in vivo and in vitro\",\n      \"pmids\": [\"30551998\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Necl-4/Cadm4's cytoplasmic terminal region (CTR) binds the first PDZ domain of Par-3, recruiting Par-3 to the adaxonal membrane of myelinating Schwann cells at sites of Necl-4/Necl-1 interaction. Knockdown of Necl-4 perturbs Par-3 localization to the inner Schwann cell membrane.\",\n      \"method\": \"Unbiased PDZ-domain proteomic screen, co-immunoprecipitation from Schwann cell lysates, co-localization by immunofluorescence, siRNA knockdown in myelinating co-cultures\",\n      \"journal\": \"Glia\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — unbiased proteomic screen confirmed by Co-IP, co-localization, and functional knockdown with defined localization readout\",\n      \"pmids\": [\"30585357\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Cadm4 forms a membrane skeletal complex with Mpp6 (Pals2), protein band 4.1G (Epb41l2), and Lin7 in Schmidt-Lanterman incisures (SLIs) of PNS myelin. In FA2H-deficient mice, this complex is enriched in aged sciatic nerve myelin alongside increased SLI number.\",\n      \"method\": \"Mass spectrometry-based proteomics of purified myelin, electron microscopy to count SLIs\",\n      \"journal\": \"Molecular neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — proteomic identification of complex in purified myelin, single study without direct interaction validation\",\n      \"pmids\": [\"35445918\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CADM4 undergoes palmitoylation at cysteine-347 (C347), catalyzed by ZDHHC3, which is required for stable plasma membrane localization. A C347A knock-in mutation blocks palmitoylation, causes CADM4 internalization and degradation, and produces severe CNS myelin abnormalities. ZDHHC3 knockout phenocopies this, reducing Cadm4 palmitoylation and causing CNS myelination defects. Altered Cadm4 palmitoylation also impairs oligodendrocyte differentiation via the WNT-β-Catenin pathway.\",\n      \"method\": \"Site-directed mutagenesis, knock-in mouse model, ZDHHC3 knockout mouse, palmitoylation assay, plasma membrane fractionation, WNT-β-Catenin pathway analysis, electrophysiology, behavioral testing\",\n      \"journal\": \"Signal transduction and targeted therapy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — site-directed mutagenesis of palmitoylation site combined with two independent genetic mouse models and multiple orthogonal readouts\",\n      \"pmids\": [\"39327467\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Necl-4/CADM4 is expressed in GABAergic inhibitory neurons and localizes at GABAergic synapses on inhibitory neurons. Necl-4 knockout increases GABAergic synapse density and synaptic molecules on inhibitory neurons via ErbB4 activation, enhances GABAergic synaptic currents, induces high-frequency firing, and causes excitotoxicity-mediated neuronal death in the hippocampus.\",\n      \"method\": \"Genetic knockout mouse, immunofluorescence, electrophysiology (mIPSC recording), ErbB4 pathway analysis, hippocampal neuron culture\",\n      \"journal\": \"Molecular neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — knockout with electrophysiology and defined pathway (ErbB4), single lab\",\n      \"pmids\": [\"40728771\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"In zebrafish, cadm4 restricts the size of the cardiac outflow tract (OFT) by limiting the production of OFT progenitor cells from the second heart field and the duration of their accumulation at the arterial pole. Knockdown causes OFT expansion; overexpression causes OFT reduction.\",\n      \"method\": \"Morpholino knockdown, mRNA overexpression, confocal live imaging, cell lineage tracing in zebrafish\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function and gain-of-function with defined progenitor cell phenotype in zebrafish ortholog\",\n      \"pmids\": [\"24813897\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CADM4 (Necl-4/SynCAM4) is a transmembrane immunoglobulin superfamily cell adhesion molecule that mediates axon-glia adhesion in both PNS and CNS: in PNS Schwann cells it binds axonal CADM3 in trans, recruits the polarity protein Par-3 via its PDZ-binding cytoplasmic domain, and requires ZDHHC3-mediated palmitoylation at C347 for stable plasma membrane localization; loss of Cadm4 or its palmitoylation causes hypermyelination, myelin outfoldings, and ion channel redistribution, while in the CNS excessive Cadm4-mediated adhesion blocks myelin elongation. Beyond myelination, CADM4 cis-interacts with VEGFR2, ErbB3, and integrin α6β4 on cell surfaces, modulating VEGF-PLCγ-ERK and ErbB2/ErbB3 signaling through PTPN13 to regulate contact inhibition and tumor suppression, and in GABAergic neurons it restrains ErbB4-dependent synaptic strengthening to prevent excitotoxic neuronal death.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"CADM4 (Necl-4/SynCAM4) is an immunoglobulin superfamily cell adhesion molecule that functions as a central mediator of axon-glia interactions during myelination and as a modulator of receptor tyrosine kinase signaling in epithelia and endothelia. In the PNS, CADM4 is expressed by myelinating Schwann cells at internodes where it binds axonal CADM3 in trans, recruits the polarity protein Par-3 via its cytoplasmic PDZ-binding domain, and requires ZDHHC3-mediated palmitoylation at C347 for stable plasma membrane retention; loss of Cadm4 or its palmitoylation causes focal hypermyelination, myelin outfoldings, and ion channel redistribution in the PNS, while in the CNS excess Cadm4-mediated adhesion blocks myelin sheet elongation and C347A knock-in mice exhibit severe CNS dysmyelination [PMID:17558405, PMID:23825401, PMID:30551998, PMID:30585357, PMID:39327467]. CADM4 also cis-interacts with VEGFR2, ErbB3, and integrin α6β4, recruiting the phosphatase PTPN13 to inhibit ErbB2/ErbB3 and VEGFR2 signaling and independently regulating the PLCγ–Raf–MEK–ERK cascade downstream of VEGF, thereby contributing to contact inhibition of growth and tumor suppression [PMID:23611113, PMID:25893857, PMID:28601637, PMID:16261159]. In GABAergic neurons, CADM4 restrains ErbB4-dependent synapse formation; its loss increases GABAergic synapse density, enhances inhibitory synaptic currents, and triggers excitotoxic neuronal death [PMID:40728771].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Identification of CADM4 (TSLL2) as a new immunoglobulin superfamily member structurally related to CADM1/TSLC1 established it as part of a discrete adhesion molecule subfamily, raising the question of whether it shares tumor-suppressor and adhesion functions.\",\n      \"evidence\": \"Molecular cloning and sequence analysis with Northern blot expression profiling\",\n      \"pmids\": [\"11536053\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional data beyond structural prediction\", \"Expression pattern not resolved at protein level\", \"No binding partners identified\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Demonstration that CADM4 mediates homophilic cell aggregation and suppresses tumor growth in xenografts established it as both an adhesion molecule and a candidate tumor suppressor, but left the molecular mechanism of tumor suppression unresolved.\",\n      \"evidence\": \"Cell aggregation assay in MDCK cells and subcutaneous xenograft of prostate cancer cells in nude mice\",\n      \"pmids\": [\"16261159\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Tumor suppression mechanism not defined\", \"Homophilic vs. heterophilic binding hierarchy unclear\", \"Endogenous relevance in non-cancer tissues not tested\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Identification of CADM4 as the principal Necl on myelinating Schwann cells and its heterophilic trans-binding to axonal CADM3 established CADM4 as the key glial adhesion molecule at the axon-Schwann cell interface, explaining how myelination initiation depends on axon-glial recognition.\",\n      \"evidence\": \"Co-immunoprecipitation, dominant-negative overexpression, soluble domain competition, and in vitro myelination assays\",\n      \"pmids\": [\"17558405\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Intracellular signaling downstream of CADM4 in Schwann cells not identified\", \"In vivo genetic validation lacking at this point\", \"Whether CADM4 functions similarly in CNS oligodendrocytes unknown\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Association of CADM4 with the actin-binding protein 4.1B and tumor suppression in renal cell carcinoma linked CADM4's cytoplasmic domain to cytoskeletal scaffolding, but the mechanistic basis of growth inhibition remained open.\",\n      \"evidence\": \"Co-immunoprecipitation from kidney tissue and nude mouse xenograft tumor suppression assay\",\n      \"pmids\": [\"21544807\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs. indirect nature of 4.1B interaction not resolved\", \"No signaling pathway analysis downstream of 4.1B\", \"Relevance to endogenous kidney physiology untested in knockout\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Two advances resolved CADM4's in vivo myelination role and its receptor tyrosine kinase regulatory mechanism: Schwann cell-specific Cadm4 knockout produced focal hypermyelination with myelin outfoldings and ion channel mislocalization, proving CADM4 constrains myelin growth via its cytoplasmic domain; concurrently, identification of cis-interactions with ErbB3 and integrin α6β4 plus recruitment of PTPN13 to inhibit ErbB2/ErbB3 signaling provided the first defined signaling pathway for CADM4-mediated contact inhibition.\",\n      \"evidence\": \"Conditional knockout and dominant-negative transgenic mice with EM, electrophysiology, and behavioral assays; Co-IP with signaling phosphorylation readouts and hemidesmosome assays in epithelial cells\",\n      \"pmids\": [\"23825401\", \"23611113\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How cytoplasmic domain restrains myelin growth mechanistically unresolved\", \"Whether PTPN13-ErbB3 axis operates in Schwann cells unknown\", \"Direct structural basis of cis-interaction with RTKs not determined\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Zebrafish cadm4 was shown to restrict cardiac outflow tract size by limiting second heart field progenitor production, revealing a developmental role outside the nervous system.\",\n      \"evidence\": \"Morpholino knockdown and mRNA overexpression with confocal live imaging and lineage tracing in zebrafish\",\n      \"pmids\": [\"24813897\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which cadm4 limits progenitor production not defined\", \"Not validated in mammalian cardiac development\", \"Morpholino-based; genetic mutant confirmation lacking\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Discovery that CADM4 cis-interacts with VEGFR2 and context-dependently either inhibits (confluent cells via PTPN13) or promotes (sparse cells via Rac1) VEGF signaling explained how a single adhesion molecule can exert opposing effects on endothelial behavior depending on cell density.\",\n      \"evidence\": \"Co-IP, siRNA knockdown, live imaging, phosphorylation and Rac1 activation assays in endothelial cells\",\n      \"pmids\": [\"25893857\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo vascular relevance not tested\", \"Switch mechanism between inhibitory and activating modes not molecularly defined\", \"Whether CADM4 directly bridges VEGFR2 and PTPN13 or acts indirectly unclear\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Epistasis experiments showed CADM4 is required for VEGF-induced PLCγ–Raf–MEK–ERK signaling independently of PTPN13 and ROCK, establishing a second, phosphatase-independent signaling arm through which CADM4 regulates endothelial proliferation.\",\n      \"evidence\": \"siRNA knockdown with phosphorylation cascade analysis and VEGFR2 internalization assay\",\n      \"pmids\": [\"28601637\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular target linking CADM4 to PLCγ not identified\", \"Functional consequence for angiogenesis in vivo untested\", \"Single lab observation\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Two studies resolved CADM4's CNS myelination role and its mechanism for organizing Schwann cell polarity: excess Cadm4 extracellular domain in oligodendrocytes created abundant but non-elongating contacts causing hypomyelination, showing that regulated adhesion-to-wrapping transition is essential; separately, CADM4's cytoplasmic tail was found to bind Par-3's first PDZ domain, recruiting it to the adaxonal Schwann cell membrane at sites of CADM3 engagement.\",\n      \"evidence\": \"Transgenic mouse and oligodendrocyte-neuron co-cultures; unbiased PDZ-domain proteomic screen with Co-IP, co-localization, and siRNA knockdown in myelinating co-cultures\",\n      \"pmids\": [\"30551998\", \"30585357\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Par-3 recruitment mediates the myelin-restraining function remains untested genetically\", \"Axonal receptors required for oligodendrocyte Cadm4 signaling only partially identified\", \"Downstream effectors of Par-3 at the adaxonal membrane not defined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Proteomic identification of a CADM4–Mpp6–4.1G–Lin7 complex in Schmidt-Lanterman incisures placed CADM4 within a defined membrane skeleton at non-compact myelin domains, suggesting a structural scaffolding role in myelin maintenance.\",\n      \"evidence\": \"Mass spectrometry of purified PNS myelin with electron microscopy quantification of SLIs in FA2H-deficient mice\",\n      \"pmids\": [\"35445918\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binary interactions within the complex not validated\", \"Functional consequence of disrupting this complex at SLIs unknown\", \"Observed enrichment in disease model; normal-state stoichiometry not established\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identification of ZDHHC3-mediated palmitoylation at C347 as essential for CADM4 plasma membrane retention resolved how post-translational modification controls CADM4 surface expression; C347A knock-in and ZDHHC3 knockout mice both exhibit severe CNS dysmyelination and impaired oligodendrocyte differentiation via aberrant WNT–β-catenin signaling.\",\n      \"evidence\": \"Site-directed mutagenesis, C347A knock-in mouse, ZDHHC3 knockout mouse, palmitoylation assay, membrane fractionation, WNT pathway analysis, electrophysiology, behavioral testing\",\n      \"pmids\": [\"39327467\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether palmitoylation similarly controls PNS myelination functions not fully explored\", \"How loss of membrane CADM4 activates WNT–β-catenin mechanistically unresolved\", \"Other potential palmitoylation sites and additional palmitoyl transferases not excluded\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Discovery that CADM4 at GABAergic synapses restrains ErbB4-dependent synapse formation on inhibitory neurons revealed a synaptic function beyond myelination: Cadm4 knockout increases GABAergic synapse density, enhances inhibitory currents, and causes excitotoxic neuronal death.\",\n      \"evidence\": \"Knockout mouse with immunofluorescence, mIPSC electrophysiology, ErbB4 pathway analysis, and hippocampal neuron culture\",\n      \"pmids\": [\"40728771\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether CADM4 directly binds ErbB4 or acts via intermediate partners not determined\", \"Cell-type-specific rescue experiments not performed\", \"Behavioral consequences of synaptic phenotype not fully characterized\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of CADM4's cis-interactions with multiple receptor tyrosine kinases, how its cytoplasmic domain coordinates Par-3 recruitment with myelin growth restraint, and whether its myelination and tumor-suppressive functions share a common signaling logic.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal or cryo-EM structure of CADM4 or its complexes\", \"Genetic epistasis between Par-3 and CADM4 in myelination not tested in vivo\", \"Unified signaling model across myelination, vascular, and tumor-suppressor contexts lacking\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [0, 1, 3, 8]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [5, 6, 7, 12]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [5, 6, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 3, 6, 9, 11]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [\n      \"CADM4-Mpp6-4.1G-Lin7 membrane skeleton\"\n    ],\n    \"partners\": [\n      \"CADM3\",\n      \"PTPN13\",\n      \"PARD3\",\n      \"EPB41L2\",\n      \"EPB41L3\",\n      \"ERBB3\",\n      \"KDR\",\n      \"ZDHHC3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\nWait, I made an error in the pathway field - I used a GO term instead of a Reactome term. Let me fix that.\n\n```json\n{\n  \"mechanistic_narrative\": \"CADM4 (Necl-4/SynCAM4) is an immunoglobulin superfamily cell adhesion molecule that functions as a central mediator of axon-glia interactions during myelination and as a modulator of receptor tyrosine kinase signaling in epithelia and endothelia. In the PNS, CADM4 is expressed by myelinating Schwann cells at internodes where it binds axonal CADM3 in trans, recruits the polarity protein Par-3 via its cytoplasmic PDZ-binding domain, and requires ZDHHC3-mediated palmitoylation at C347 for stable plasma membrane retention; loss of Cadm4 or its palmitoylation causes focal hypermyelination, myelin outfoldings, and ion channel redistribution in the PNS, while in the CNS excess Cadm4-mediated adhesion blocks myelin sheet elongation and C347A knock-in mice exhibit severe CNS dysmyelination [PMID:17558405, PMID:23825401, PMID:30551998, PMID:30585357, PMID:39327467]. CADM4 also cis-interacts with VEGFR2, ErbB3, and integrin α6β4, recruiting the phosphatase PTPN13 to inhibit ErbB2/ErbB3 and VEGFR2 signaling and independently regulating the PLCγ–Raf–MEK–ERK cascade downstream of VEGF, thereby contributing to contact inhibition of growth and tumor suppression [PMID:23611113, PMID:25893857, PMID:28601637, PMID:16261159]. In GABAergic neurons, CADM4 restrains ErbB4-dependent synapse formation; its loss increases GABAergic synapse density, enhances inhibitory synaptic currents, and triggers excitotoxic neuronal death [PMID:40728771].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Identification of CADM4 (TSLL2) as a new immunoglobulin superfamily member structurally related to CADM1/TSLC1 established it as part of a discrete adhesion molecule subfamily, raising the question of whether it shares tumor-suppressor and adhesion functions.\",\n      \"evidence\": \"Molecular cloning and sequence analysis with Northern blot expression profiling\",\n      \"pmids\": [\"11536053\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional data beyond structural prediction\", \"Expression pattern not resolved at protein level\", \"No binding partners identified\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Demonstration that CADM4 mediates homophilic cell aggregation and suppresses tumor growth in xenografts established it as both an adhesion molecule and a candidate tumor suppressor, but left the molecular mechanism of tumor suppression unresolved.\",\n      \"evidence\": \"Cell aggregation assay in MDCK cells and subcutaneous xenograft of prostate cancer cells in nude mice\",\n      \"pmids\": [\"16261159\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Tumor suppression mechanism not defined\", \"Homophilic vs. heterophilic binding hierarchy unclear\", \"Endogenous relevance in non-cancer tissues not tested\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Identification of CADM4 as the principal Necl on myelinating Schwann cells and its heterophilic trans-binding to axonal CADM3 established CADM4 as the key glial adhesion molecule at the axon-Schwann cell interface, explaining how myelination initiation depends on axon-glial recognition.\",\n      \"evidence\": \"Co-immunoprecipitation, dominant-negative overexpression, soluble domain competition, and in vitro myelination assays\",\n      \"pmids\": [\"17558405\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Intracellular signaling downstream of CADM4 in Schwann cells not identified\", \"In vivo genetic validation lacking at this point\", \"Whether CADM4 functions similarly in CNS oligodendrocytes unknown\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Association of CADM4 with the actin-binding protein 4.1B and tumor suppression in renal cell carcinoma linked CADM4's cytoplasmic domain to cytoskeletal scaffolding, but the mechanistic basis of growth inhibition remained open.\",\n      \"evidence\": \"Co-immunoprecipitation from kidney tissue and nude mouse xenograft tumor suppression assay\",\n      \"pmids\": [\"21544807\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs. indirect nature of 4.1B interaction not resolved\", \"No signaling pathway analysis downstream of 4.1B\", \"Relevance to endogenous kidney physiology untested in knockout\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Two advances resolved CADM4's in vivo myelination role and its receptor tyrosine kinase regulatory mechanism: Schwann cell-specific Cadm4 knockout produced focal hypermyelination with myelin outfoldings and ion channel mislocalization, proving CADM4 constrains myelin growth via its cytoplasmic domain; concurrently, identification of cis-interactions with ErbB3 and integrin α6β4 plus recruitment of PTPN13 to inhibit ErbB2/ErbB3 signaling provided the first defined signaling pathway for CADM4-mediated contact inhibition.\",\n      \"evidence\": \"Conditional knockout and dominant-negative transgenic mice with EM, electrophysiology, and behavioral assays; Co-IP with signaling phosphorylation readouts and hemidesmosome assays in epithelial cells\",\n      \"pmids\": [\"23825401\", \"23611113\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How cytoplasmic domain restrains myelin growth mechanistically unresolved\", \"Whether PTPN13-ErbB3 axis operates in Schwann cells unknown\", \"Direct structural basis of cis-interaction with RTKs not determined\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Zebrafish cadm4 was shown to restrict cardiac outflow tract size by limiting second heart field progenitor production, revealing a developmental role outside the nervous system.\",\n      \"evidence\": \"Morpholino knockdown and mRNA overexpression with confocal live imaging and lineage tracing in zebrafish\",\n      \"pmids\": [\"24813897\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which cadm4 limits progenitor production not defined\", \"Not validated in mammalian cardiac development\", \"Morpholino-based; genetic mutant confirmation lacking\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Discovery that CADM4 cis-interacts with VEGFR2 and context-dependently either inhibits (confluent cells via PTPN13) or promotes (sparse cells via Rac1) VEGF signaling explained how a single adhesion molecule can exert opposing effects on endothelial behavior depending on cell density.\",\n      \"evidence\": \"Co-IP, siRNA knockdown, live imaging, phosphorylation and Rac1 activation assays in endothelial cells\",\n      \"pmids\": [\"25893857\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo vascular relevance not tested\", \"Switch mechanism between inhibitory and activating modes not molecularly defined\", \"Whether CADM4 directly bridges VEGFR2 and PTPN13 or acts indirectly unclear\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Epistasis experiments showed CADM4 is required for VEGF-induced PLCγ–Raf–MEK–ERK signaling independently of PTPN13 and ROCK, establishing a second, phosphatase-independent signaling arm through which CADM4 regulates endothelial proliferation.\",\n      \"evidence\": \"siRNA knockdown with phosphorylation cascade analysis and VEGFR2 internalization assay\",\n      \"pmids\": [\"28601637\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular target linking CADM4 to PLCγ not identified\", \"Functional consequence for angiogenesis in vivo untested\", \"Single lab observation\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Two studies resolved CADM4's CNS myelination role and its mechanism for organizing Schwann cell polarity: excess Cadm4 extracellular domain in oligodendrocytes created abundant but non-elongating contacts causing hypomyelination, showing that regulated adhesion-to-wrapping transition is essential; separately, CADM4's cytoplasmic tail was found to bind Par-3's first PDZ domain, recruiting it to the adaxonal Schwann cell membrane at sites of CADM3 engagement.\",\n      \"evidence\": \"Transgenic mouse and oligodendrocyte-neuron co-cultures; unbiased PDZ-domain proteomic screen with Co-IP, co-localization, and siRNA knockdown in myelinating co-cultures\",\n      \"pmids\": [\"30551998\", \"30585357\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Par-3 recruitment mediates the myelin-restraining function remains untested genetically\", \"Axonal receptors required for oligodendrocyte Cadm4 signaling only partially identified\", \"Downstream effectors of Par-3 at the adaxonal membrane not defined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Proteomic identification of a CADM4–Mpp6–4.1G–Lin7 complex in Schmidt-Lanterman incisures placed CADM4 within a defined membrane skeleton at non-compact myelin domains, suggesting a structural scaffolding role in myelin maintenance.\",\n      \"evidence\": \"Mass spectrometry of purified PNS myelin with electron microscopy quantification of SLIs in FA2H-deficient mice\",\n      \"pmids\": [\"35445918\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binary interactions within the complex not validated\", \"Functional consequence of disrupting this complex at SLIs unknown\", \"Observed enrichment in disease model; normal-state stoichiometry not established\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identification of ZDHHC3-mediated palmitoylation at C347 as essential for CADM4 plasma membrane retention resolved how post-translational modification controls CADM4 surface expression; C347A knock-in and ZDHHC3 knockout mice both exhibit severe CNS dysmyelination and impaired oligodendrocyte differentiation via aberrant WNT–β-catenin signaling.\",\n      \"evidence\": \"Site-directed mutagenesis, C347A knock-in mouse, ZDHHC3 knockout mouse, palmitoylation assay, membrane fractionation, WNT pathway analysis, electrophysiology, behavioral testing\",\n      \"pmids\": [\"39327467\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether palmitoylation similarly controls PNS myelination functions not fully explored\", \"How loss of membrane CADM4 activates WNT–β-catenin mechanistically unresolved\", \"Other potential palmitoylation sites and additional palmitoyl transferases not excluded\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Discovery that CADM4 at GABAergic synapses restrains ErbB4-dependent synapse formation on inhibitory neurons revealed a synaptic function beyond myelination: Cadm4 knockout increases GABAergic synapse density, enhances inhibitory currents, and causes excitotoxic neuronal death.\",\n      \"evidence\": \"Knockout mouse with immunofluorescence, mIPSC electrophysiology, ErbB4 pathway analysis, and hippocampal neuron culture\",\n      \"pmids\": [\"40728771\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether CADM4 directly binds ErbB4 or acts via intermediate partners not determined\", \"Cell-type-specific rescue experiments not performed\", \"Behavioral consequences of synaptic phenotype not fully characterized\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of CADM4's cis-interactions with multiple receptor tyrosine kinases, how its cytoplasmic domain coordinates Par-3 recruitment with myelin growth restraint, and whether its myelination and tumor-suppressive functions share a common signaling logic.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal or cryo-EM structure of CADM4 or its complexes\", \"Genetic epistasis between Par-3 and CADM4 in myelination not tested in vivo\", \"Unified signaling model across myelination, vascular, and tumor-suppressor contexts lacking\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [0, 1, 3, 8]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [5, 6, 7, 12]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [5, 6, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 3, 6, 9, 11]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1500931\", \"supporting_discovery_ids\": [0, 1, 3, 8]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5, 6, 7, 12]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [8, 13]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [0, 1, 9, 12]}\n    ],\n    \"complexes\": [\n      \"CADM4-Mpp6-4.1G-Lin7 membrane skeleton\"\n    ],\n    \"partners\": [\n      \"CADM3\",\n      \"PTPN13\",\n      \"PARD3\",\n      \"EPB41L2\",\n      \"ERBB3\",\n      \"KDR\",\n      \"ZDHHC3\",\n      \"MPP6\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}