{"gene":"EPHA8","run_date":"2026-06-09T23:54:43","timeline":{"discoveries":[{"year":1991,"finding":"EphA8 (eek) encodes a receptor protein-tyrosine kinase of the Eph subclass, containing all conserved amino acid residues in the catalytic domain of protein-tyrosine kinases, and is most highly expressed in brain.","method":"cDNA cloning, Northern blot analysis","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cDNA cloning with sequence analysis and Northern blot, single lab, two orthogonal methods establishing identity and expression","pmids":["1648701"],"is_preprint":false},{"year":1997,"finding":"EphA8 (Eek) knockout mice show aberrant axonal projections: tectal neurons in the superior colliculus fail to reach contralateral inferior colliculus targets, and an abnormal ipsilateral tract projects to ventral cervical spinal cord, establishing EphA8 as required for axonal pathfinding in the mammalian nervous system.","method":"Homologous recombination knockout, axonal tracing (anterograde and retrograde labeling)","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean germline knockout with two orthogonal axonal tracing methods establishing specific pathfinding phenotype","pmids":["9214628"],"is_preprint":false},{"year":1997,"finding":"EphA8 (Eek) receptor can be activated by at least three GPI-linked ephrin-A ligands (Elf-1/Cek7-L, Ehk1-L/Efl-2/Lerk3, and AL-1/RAGS), which bind to and tyrosine-phosphorylate EphA8 expressed in NIH3T3 cells.","method":"Chimeric Fc-fusion ligand binding assays, receptor phosphorylation assays in transfected NIH3T3 cells","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ligand binding and receptor activation confirmed with chimeric proteins, single lab, two orthogonal methods","pmids":["9053851"],"is_preprint":false},{"year":1999,"finding":"Tyr-615 (juxtamembrane) and Tyr-838 (kinase domain) are major autophosphorylation sites of EphA8. Mutation of Tyr-838 drastically reduces catalytic activity. Phospho-Tyr-615 selectively mediates binding to the Fyn SH2 domain over Src and RasGAP SH2 domains. Mutation of either site reduces EphA8-Fyn association in intact cells and attenuates cell attachment responses.","method":"2D phosphopeptide mapping, in vitro kinase assay, site-directed mutagenesis, in vitro SH2 binding, co-immunoprecipitation","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro kinase assay with mutagenesis, 2D phosphopeptide mapping, and Co-IP, single lab but multiple orthogonal methods","pmids":["10498895"],"is_preprint":false},{"year":1999,"finding":"EphA8 binds and is activated by ephrin-A1 and ephrin-A4 (GPI-linked), but not transmembrane ephrin-B1, -B2, or -B3, confirming EphA8 functions exclusively as a GPI-linked ephrin-A-dependent receptor tyrosine kinase.","method":"Chimeric Fc-fusion ligand binding assay, receptor tyrosine phosphorylation in transfected NIH3T3 fibroblasts","journal":"Molecules and cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ligand binding and phosphorylation assays with panel of ephrin-Fc chimeras, single lab","pmids":["10515610"],"is_preprint":false},{"year":2001,"finding":"EphA8 promotes cell adhesion to fibronectin via alpha5beta1 or beta3 integrins in a tyrosine kinase-independent manner. This function requires ephrin-A binding to the extracellular domain and the juxtamembrane intracellular segment. EphA8 associates with the p110gamma isoform of PI 3-kinase via its juxtamembrane segment, and p110gamma lipid kinase activity is required for integrin-mediated cell adhesion.","method":"Cell adhesion assay, kinase-inactive mutant analysis, EphA8 deletion/point mutants, PI 3-kinase activity assay, in vitro pulldown, dominant-negative p110gamma lipid kinase-inactive mutant","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro binding, mutagenesis, kinase assay, and cell adhesion phenotype with dominant-negative, single lab with multiple orthogonal methods","pmids":["11416136"],"is_preprint":false},{"year":2003,"finding":"EphA8-stimulated cell migration on fibronectin requires p110gamma PI 3-kinase activity. Ephrin-A5 stimulation increases stability of the p110gamma–EphA8 complex and enhances PI 3-kinase activity. A lipid kinase-inactive p110gamma dominantly suppresses EphA8-stimulated migration. EphA8 tyrosine kinase activity is dispensable for this process.","method":"PI 3-kinase activity assay, dominant-negative lipid kinase-inactive p110gamma mutant, cell migration assay on fibronectin","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional migration assay with dominant-negative mutant and kinase assay, single lab","pmids":["12681484"],"is_preprint":false},{"year":2003,"finding":"EphA8 directly phosphorylates and activates low molecular weight phosphotyrosine protein phosphatase (LMW-PTP) in vitro, and the phosphorylated LMW-PTP in turn dephosphorylates EphA8, suggesting a feedback-control mechanism of EphA8 autokinase activity.","method":"In vitro kinase assay, in vitro phosphatase activity assay","journal":"Journal of biochemistry and molecular biology","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro reconstitution with two enzymes, single lab, single study","pmids":["12787484"],"is_preprint":false},{"year":2005,"finding":"EphA8 induces sustained MAP kinase (MAPK/ERK) activation and nuclear relocalization of activated MAPK, driving neurite outgrowth in NG108-15 neuronal cells. This requires the tyrosine kinase domain but not kinase catalytic activity, and is independent of ligand stimulation.","method":"Deletion mutant analysis, MAPK activity assay, immunofluorescence localization, kinase inhibitors, neurite outgrowth assay","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — deletion mutants, pharmacological inhibition, and kinase activity assay, single lab","pmids":["15782114"],"is_preprint":false},{"year":2007,"finding":"The PTB domain-containing proteins AIDA-1b and Odin (Anks family) associate with the juxtamembrane domain of EphA8 in response to ephrin-A5 ligand stimulation. This interaction is independent of EphA8 tyrosine kinase activity. Odin is identified as the more physiologically relevant partner; siRNA-mediated Odin knockdown diminishes EphA8-mediated inhibition of cell migration and neurite retraction. Overexpression of the Odin PTB domain alone (dominant-negative) attenuates EphA8-mediated cell migration inhibition.","method":"Co-immunoprecipitation, PTB domain pulldown, siRNA knockdown, dominant-negative overexpression, cell migration assay, neurite retraction assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP, dominant-negative, and siRNA knockdown with multiple cellular phenotype readouts, single lab","pmids":["17875921"],"is_preprint":false},{"year":2010,"finding":"EphA8 undergoes clathrin-mediated endocytosis upon ephrin-A5 stimulation. The juxtamembrane region of EphA8 is required for endocytosis of EphA8-ephrinA5 complexes and for association with Tiam-1, a Rac-specific GEF. Tiam-1 knockdown impairs endocytosis of EphA8-ephrinA5 complexes, and an endocytosis-defective EphA8 juxtamembrane mutant shows reduced Rac activation after ephrin-A5 stimulation.","method":"Endocytosis assay, EphA8 deletion mutant analysis, Co-immunoprecipitation, siRNA knockdown of Tiam-1, Rac activity assay","journal":"Molecules and cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — deletion mutants, Co-IP, siRNA knockdown with endocytosis and Rac activation readouts, single lab","pmids":["20496116"],"is_preprint":false},{"year":2012,"finding":"RINL (a Rab5-subfamily GEF) interacts with Odin and forms a ternary complex with EphA8. RINL expression reduces EphA8 protein levels in a manner dependent on its GEF activity and interaction with Odin; RINL knockdown increases EphA8 levels, placing RINL in the EphA8 degradation pathway via the endosomal/Rab5 system.","method":"Co-immunoprecipitation, GTP-bound Rab5 assay, RINL knockdown, RINL overexpression with GEF-inactive mutant, Western blot for EphA8 levels","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, GEF activity assay, and siRNA knockdown with receptor level readout, single lab","pmids":["22291991"],"is_preprint":false},{"year":2013,"finding":"Ectopic expression of EphA8-Fc in transgenic mouse embryos induces caspase-dependent apoptosis of ephrin-A5-expressing neural epithelial cells, causing a dramatic decrease in brain size, indicating that EphA8 can drive reverse signaling through ephrin-As to activate proapoptotic pathways during brain development.","method":"Transgenic mouse ectopic expression, in vivo and in vitro apoptosis assay, caspase inhibitor treatment, neuroepithelial cell culture","journal":"Developmental neurobiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — transgenic in vivo model and in vitro cell culture with caspase inhibitor, single lab","pmids":["23696555"],"is_preprint":false},{"year":2024,"finding":"In human rhabdomyosarcoma cells, ephrin-A5 binds and signals through EphA8 (not EphA7), and this signaling inhibits cell proliferation, identifying EphA8 as the relevant receptor for ephrin-A5-mediated anti-proliferative effects in this context.","method":"Binding assay with Fc chimeras, signaling assay, cell proliferation assay in human RMS cell lines","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — preprint, single lab, single binding/functional assay, limited mechanistic detail in abstract","pmids":["bio_10.1101_2024.12.23.629471"],"is_preprint":true}],"current_model":"EphA8 is an Eph-family receptor tyrosine kinase that binds multiple GPI-linked ephrin-A ligands (A1–A5) and signals through both kinase-dependent and kinase-independent mechanisms: ligand-independent, it drives sustained MAPK activation and neurite outgrowth; ligand-stimulated, it recruits p110gamma PI3K via its juxtamembrane domain (kinase-independently) to promote integrin-mediated adhesion and cell migration on fibronectin, recruits Odin/AIDA-1b PTB-domain scaffolds to inhibit cell migration, undergoes Tiam-1-dependent clathrin-mediated endocytosis coupled to Rac activation, and is targeted for degradation via a RINL–Odin–Rab5 axis; autophosphorylation at Tyr-838 sustains catalytic activity while pTyr-615 recruits Fyn kinase, and EphA8 also phosphorylates and activates LMW-PTP in a feedback loop; in vivo, EphA8 is required for axonal pathfinding in the superior colliculus and, through reverse signaling via ephrin-A5, regulates neural epithelial cell survival during brain development."},"narrative":{"mechanistic_narrative":"EphA8 is an Eph-subclass receptor protein-tyrosine kinase, most highly expressed in brain, that governs axonal pathfinding and developmental cell-fate decisions in the mammalian nervous system [PMID:1648701, PMID:9214628]. It functions as a GPI-linked ephrin-A-selective receptor, binding and being tyrosine-phosphorylated by ephrin-A ligands (A1, A4, A5) but not transmembrane ephrin-B ligands [PMID:9053851, PMID:10515610]. Its juxtamembrane segment is a central signaling hub: it carries the autophosphorylation site Tyr-615 that selectively recruits Fyn, while Tyr-838 in the kinase domain sustains catalytic activity [PMID:10498895]. Strikingly, several EphA8 outputs are kinase-independent — ligand-engaged EphA8 recruits the p110gamma isoform of PI 3-kinase through its juxtamembrane segment to drive integrin-mediated adhesion and migration on fibronectin [PMID:11416136, PMID:12681484], and the kinase domain (but not its catalytic activity) is required for sustained MAPK activation and neurite outgrowth [PMID:15782114]. The same juxtamembrane region nucleates ligand-dependent recruitment of the Anks-family PTB scaffolds Odin and AIDA-1b, which restrain cell migration and promote neurite retraction [PMID:17875921], and couples receptor activation to Tiam-1-dependent, clathrin-mediated endocytosis and Rac activation [PMID:20496116]; receptor turnover is further controlled by the Rab5 GEF RINL acting through Odin [PMID:22291991]. EphA8 also engages a phosphatase feedback loop by phosphorylating and activating LMW-PTP, which in turn dephosphorylates the receptor [PMID:12787484]. Beyond forward signaling, EphA8 can drive reverse signaling through ephrin-A5 to trigger caspase-dependent apoptosis of neural epithelial cells during brain development [PMID:23696555].","teleology":[{"year":1991,"claim":"Established the molecular identity of EphA8 as a brain-enriched Eph-family receptor tyrosine kinase, defining the protein class before any function was known.","evidence":"cDNA cloning and sequence analysis with Northern blot expression profiling","pmids":["1648701"],"confidence":"Medium","gaps":["No ligand identified","No in vivo function established","Catalytic activity inferred from sequence, not demonstrated"]},{"year":1997,"claim":"Defined the in vivo requirement for EphA8, showing it is needed for correct axonal pathfinding rather than serving a dispensable role.","evidence":"Germline knockout mouse with anterograde and retrograde axonal tracing in the superior colliculus","pmids":["9214628"],"confidence":"High","gaps":["Did not identify the ligand or downstream effectors mediating pathfinding","Cell-autonomy of the defect not resolved"]},{"year":1997,"claim":"Identified the activating ligands, establishing that EphA8 is engaged and phosphorylated by GPI-linked ephrin-A ligands.","evidence":"Fc-fusion ligand binding and receptor phosphorylation assays in transfected NIH3T3 cells","pmids":["9053851"],"confidence":"Medium","gaps":["Ligand selectivity versus ephrin-B not yet tested","Downstream signaling not addressed"]},{"year":1999,"claim":"Confirmed exclusive ephrin-A (GPI-linked) ligand selectivity, ruling out transmembrane ephrin-B ligands.","evidence":"Ephrin-Fc chimera panel binding and receptor phosphorylation in NIH3T3 fibroblasts","pmids":["10515610"],"confidence":"Medium","gaps":["Physiological ligand in vivo not pinpointed","Affinities not quantified"]},{"year":1999,"claim":"Mapped the key autophosphorylation sites and linked them to specific outputs, distinguishing a catalytic-sustaining site from an SH2-docking site.","evidence":"2D phosphopeptide mapping, in vitro kinase assay, mutagenesis, in vitro SH2 binding, and Co-IP","pmids":["10498895"],"confidence":"High","gaps":["Functional consequence of Fyn recruitment downstream not detailed","Stoichiometry of phosphorylation in vivo unknown"]},{"year":2001,"claim":"Revealed a kinase-independent adhesion mechanism in which EphA8 recruits p110gamma PI 3-kinase via its juxtamembrane segment to drive integrin-mediated adhesion.","evidence":"Cell adhesion assays with kinase-inactive and deletion mutants, in vitro pulldown, and dominant-negative lipid kinase-dead p110gamma","pmids":["11416136"],"confidence":"High","gaps":["Structural basis of the p110gamma juxtamembrane interaction not resolved","In vivo relevance of the adhesion role untested"]},{"year":2003,"claim":"Extended the p110gamma axis to cell migration, showing ligand stabilizes the complex and that lipid kinase activity, not EphA8 catalysis, drives motility.","evidence":"PI 3-kinase activity assay, dominant-negative lipid kinase-dead p110gamma, and fibronectin migration assay","pmids":["12681484"],"confidence":"Medium","gaps":["Downstream effectors of p110gamma in migration not identified","Connection to integrin signaling not mechanistically closed"]},{"year":2003,"claim":"Uncovered a phosphatase feedback loop in which EphA8 activates LMW-PTP, which then dephosphorylates the receptor.","evidence":"In vitro kinase and phosphatase activity assays with purified enzymes","pmids":["12787484"],"confidence":"Medium","gaps":["In vitro reconstitution only; cellular relevance not established","Effect on downstream signaling not measured"]},{"year":2005,"claim":"Demonstrated a ligand- and catalysis-independent route to sustained MAPK signaling and neurite outgrowth requiring the kinase domain as a scaffold.","evidence":"Deletion mutants, kinase inhibitors, MAPK activity assay, and neurite outgrowth assay in NG108-15 cells","pmids":["15782114"],"confidence":"Medium","gaps":["Adaptors linking the kinase domain to MAPK not identified","Reconciliation with kinase-dependent outputs unresolved"]},{"year":2007,"claim":"Identified Odin/AIDA-1b PTB scaffolds as ligand-induced juxtamembrane partners that restrain migration and promote neurite retraction, defining an inhibitory branch of signaling.","evidence":"Reciprocal Co-IP, PTB-domain pulldown, siRNA knockdown, dominant-negative PTB overexpression, and migration/retraction assays","pmids":["17875921"],"confidence":"High","gaps":["Downstream effectors of Odin in EphA8 inhibition unmapped","Interplay with the p110gamma promigratory branch unclear"]},{"year":2010,"claim":"Linked receptor activation to clathrin-mediated endocytosis and Rac activation through juxtamembrane recruitment of the GEF Tiam-1.","evidence":"Endocytosis and Rac activity assays, deletion mutants, Co-IP, and Tiam-1 knockdown","pmids":["20496116"],"confidence":"Medium","gaps":["Whether endocytosis terminates or propagates signaling not resolved","In vivo role of EphA8 internalization untested"]},{"year":2012,"claim":"Placed EphA8 in a degradative pathway, showing the Rab5 GEF RINL acts via Odin to lower receptor levels.","evidence":"Co-IP, GTP-Rab5 assay, RINL knockdown/overexpression with GEF-inactive mutant, and EphA8 Western blots","pmids":["22291991"],"confidence":"Medium","gaps":["Lysosomal versus proteasomal fate not distinguished","Physiological context of receptor turnover unknown"]},{"year":2013,"claim":"Showed EphA8 can act as a ligand for reverse signaling, driving caspase-dependent apoptosis of ephrin-A5-expressing neural epithelium during brain development.","evidence":"Transgenic embryo ectopic EphA8-Fc expression, in vivo/in vitro apoptosis assays, and caspase inhibition","pmids":["23696555"],"confidence":"Medium","gaps":["Ephrin-A5 reverse-signaling effectors not identified","Relevance to endogenous EphA8 spatial gradients unclear"]},{"year":2024,"claim":"Implicated EphA8 as the relevant ephrin-A5 receptor mediating anti-proliferative signaling in human rhabdomyosarcoma cells.","evidence":"Fc-chimera binding, signaling, and proliferation assays in RMS cell lines (preprint)","pmids":["bio_10.1101_2024.12.23.629471"],"confidence":"Low","gaps":["Preprint, single lab with limited mechanistic detail","Signaling pathway driving growth arrest not defined","In vivo tumor relevance untested"]},{"year":null,"claim":"How the competing promigratory (p110gamma/Tiam-1/Rac) and antimigratory (Odin) branches are integrated downstream of a single juxtamembrane hub, and how kinase-dependent and kinase-independent outputs are coordinated in vivo, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the juxtamembrane signaling complex","No in vivo dissection of which downstream branch mediates the axonal pathfinding phenotype"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[3,7]},{"term_id":"GO:0001618","term_label":"virus receptor activity","supporting_discovery_ids":[2,4]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[2,5]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[5,10]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[10,11]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[3,5,8]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[1,12]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[10,11]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[12]}],"complexes":[],"partners":["EFNA5","PIK3CG","FYN","ANKS1A","ANKS1B","TIAM1","RINL","ACP1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P29322","full_name":"Ephrin type-A receptor 8","aliases":["EPH- and ELK-related kinase","EPH-like kinase 3","EK3","hEK3","Tyrosine-protein kinase receptor EEK"],"length_aa":1005,"mass_kda":111.0,"function":"Receptor tyrosine kinase which binds promiscuously GPI-anchored ephrin-A family ligands residing on adjacent cells, leading to contact-dependent bidirectional signaling into neighboring cells. The signaling pathway downstream of the receptor is referred to as forward signaling while the signaling pathway downstream of the ephrin ligand is referred to as reverse signaling. The GPI-anchored ephrin-A EFNA2, EFNA3, and EFNA5 are able to activate EPHA8 through phosphorylation. With EFNA5 may regulate integrin-mediated cell adhesion and migration on fibronectin substrate but also neurite outgrowth. During development of the nervous system also plays a role in axon guidance. Downstream effectors of the EPHA8 signaling pathway include FYN which promotes cell adhesion upon activation by EPHA8 and the MAP kinases in the stimulation of neurite outgrowth (By similarity)","subcellular_location":"Cell membrane; Cell projection; Early endosome membrane","url":"https://www.uniprot.org/uniprotkb/P29322/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/EPHA8","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/EPHA8","total_profiled":1310},"omim":[{"mim_id":"620678","title":"RAS AND RAB INTERACTOR-LIKE PROTEIN; RINL","url":"https://www.omim.org/entry/620678"},{"mim_id":"618462","title":"BLEEDING DISORDER, PLATELET-TYPE, 22; BDPLT22","url":"https://www.omim.org/entry/618462"},{"mim_id":"603688","title":"PROSTATE CANCER/BRAIN CANCER SUSCEPTIBILITY","url":"https://www.omim.org/entry/603688"},{"mim_id":"600997","title":"EPHRIN RECEPTOR EphB2; EPHB2","url":"https://www.omim.org/entry/600997"},{"mim_id":"176945","title":"EPHRIN RECEPTOR EphA8; EPHA8","url":"https://www.omim.org/entry/176945"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"choroid plexus","ntpm":31.5}],"url":"https://www.proteinatlas.org/search/EPHA8"},"hgnc":{"alias_symbol":["Hek3"],"prev_symbol":["EEK"]},"alphafold":{"accession":"P29322","domains":[{"cath_id":"2.60.120.260","chopping":"29-205","consensus_level":"high","plddt":89.081,"start":29,"end":205},{"cath_id":"2.60.40.1770","chopping":"208-263","consensus_level":"medium","plddt":90.2759,"start":208,"end":263},{"cath_id":"2.60.40.10","chopping":"333-436","consensus_level":"medium","plddt":91.1088,"start":333,"end":436},{"cath_id":"2.60.40.10","chopping":"447-532","consensus_level":"high","plddt":90.2473,"start":447,"end":532},{"cath_id":"3.30.200.20","chopping":"625-715","consensus_level":"high","plddt":81.8366,"start":625,"end":715},{"cath_id":"1.10.510.10","chopping":"720-903","consensus_level":"high","plddt":84.6943,"start":720,"end":903},{"cath_id":"1.10.150.50","chopping":"936-999","consensus_level":"high","plddt":80.3441,"start":936,"end":999}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P29322","model_url":"https://alphafold.ebi.ac.uk/files/AF-P29322-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P29322-F1-predicted_aligned_error_v6.png","plddt_mean":80.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=EPHA8","jax_strain_url":"https://www.jax.org/strain/search?query=EPHA8"},"sequence":{"accession":"P29322","fasta_url":"https://rest.uniprot.org/uniprotkb/P29322.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P29322/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P29322"}},"corpus_meta":[{"pmid":"9214628","id":"PMC_9214628","title":"Aberrant axonal projections in mice lacking EphA8 (Eek) tyrosine protein kinase receptors.","date":"1997","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/9214628","citation_count":88,"is_preprint":false},{"pmid":"11416136","id":"PMC_11416136","title":"The EphA8 receptor regulates integrin activity through p110gamma phosphatidylinositol-3 kinase in a tyrosine kinase activity-independent manner.","date":"2001","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/11416136","citation_count":85,"is_preprint":false},{"pmid":"1648701","id":"PMC_1648701","title":"eek and erk, new members of the eph subclass of receptor protein-tyrosine kinases.","date":"1991","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/1648701","citation_count":60,"is_preprint":false},{"pmid":"25683004","id":"PMC_25683004","title":"miR-10a controls glioma migration and invasion through regulating epithelial-mesenchymal transition via EphA8.","date":"2015","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/25683004","citation_count":55,"is_preprint":false},{"pmid":"15782114","id":"PMC_15782114","title":"The EphA8 receptor induces sustained MAP kinase activation to promote neurite outgrowth in neuronal cells.","date":"2005","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/15782114","citation_count":40,"is_preprint":false},{"pmid":"10498895","id":"PMC_10498895","title":"Phosphorylation at Tyr-838 in the kinase domain of EphA8 modulates Fyn binding to the Tyr-615 site by enhancing tyrosine kinase activity.","date":"1999","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/10498895","citation_count":28,"is_preprint":false},{"pmid":"17875921","id":"PMC_17875921","title":"Identification of phosphotyrosine binding domain-containing proteins as novel downstream targets of the EphA8 signaling function.","date":"2007","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/17875921","citation_count":24,"is_preprint":false},{"pmid":"20496116","id":"PMC_20496116","title":"EphA8-ephrinA5 signaling and clathrin-mediated endocytosis is regulated by Tiam-1, a Rac-specific guanine nucleotide exchange factor.","date":"2010","source":"Molecules and cells","url":"https://pubmed.ncbi.nlm.nih.gov/20496116","citation_count":22,"is_preprint":false},{"pmid":"9053851","id":"PMC_9053851","title":"The Eek receptor, a member of the Eph family of tyrosine protein kinases, can be activated by three different Eph family ligands.","date":"1997","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/9053851","citation_count":20,"is_preprint":false},{"pmid":"23696555","id":"PMC_23696555","title":"Expression of EphA8-Fc in transgenic mouse embryos induces apoptosis of neural epithelial cells during brain development.","date":"2013","source":"Developmental neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/23696555","citation_count":19,"is_preprint":false},{"pmid":"33530159","id":"PMC_33530159","title":"Bone marrow stromal cells derived exosomal miR-10a and miR-16 may be involved in progression of patients with multiple myeloma by regulating EPHA8 or IGF1R/CCND1.","date":"2021","source":"Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/33530159","citation_count":13,"is_preprint":false},{"pmid":"22291991","id":"PMC_22291991","title":"RINL, guanine nucleotide exchange factor Rab5-subfamily, is involved in the EphA8-degradation pathway with odin.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22291991","citation_count":12,"is_preprint":false},{"pmid":"12681484","id":"PMC_12681484","title":"The p110 gamma PI-3 kinase is required for EphA8-stimulated cell migration.","date":"2003","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/12681484","citation_count":11,"is_preprint":false},{"pmid":"17927897","id":"PMC_17927897","title":"Engineering lacZ Reporter gene into an ephA8 bacterial artificial chromosome using a highly efficient bacterial recombination system.","date":"2007","source":"Journal of biochemistry and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/17927897","citation_count":10,"is_preprint":false},{"pmid":"10855796","id":"PMC_10855796","title":"Genomic structure and promoter analysis of the mouse EphA8 receptor tyrosine kinase gene.","date":"2000","source":"DNA and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/10855796","citation_count":9,"is_preprint":false},{"pmid":"12787484","id":"PMC_12787484","title":"The EphA8 receptor phosphorylates and activates low molecular weight phosphotyrosine protein phosphatase in vitro.","date":"2003","source":"Journal of biochemistry and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/12787484","citation_count":9,"is_preprint":false},{"pmid":"10515610","id":"PMC_10515610","title":"Characterization of ephrin-A1 and ephrin-A4 as ligands for the EphA8 receptor protein tyrosine kinase.","date":"1999","source":"Molecules and cells","url":"https://pubmed.ncbi.nlm.nih.gov/10515610","citation_count":7,"is_preprint":false},{"pmid":"12666197","id":"PMC_12666197","title":"Identification of an enhancer region in the mouse ephA8 locus directing expression to the anterior region of the dorsal mesencephalon.","date":"2003","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/12666197","citation_count":7,"is_preprint":false},{"pmid":"22110341","id":"PMC_22110341","title":"Ectopic Expression of Ephrin-A5 Under the EphA8 Promoter at the Anterior Region of the Superior Colliculus.","date":"2010","source":"Experimental neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/22110341","citation_count":3,"is_preprint":false},{"pmid":"38629918","id":"PMC_38629918","title":"LGP2 Facilitates Bacterial Escape through Binding Peptidoglycan via EEK Motif and Suppressing NOD2-RIP2 Axis in Cyprinidae and Xenocyprididae Families.","date":"2024","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/38629918","citation_count":1,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.12.23.629471","title":"Ephrin-A5 or EphA7 stimulation is anti-proliferative for human rhabdomyosarcoma  <i>in vitro</i>","date":"2024-12-23","source":"bioRxiv","url":"https://doi.org/10.1101/2024.12.23.629471","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11282,"output_tokens":3703,"usd":0.044695,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11296,"output_tokens":4267,"usd":0.081577,"stage2_stop_reason":"end_turn"},"total_usd":0.126272,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1991,\n      \"finding\": \"EphA8 (eek) encodes a receptor protein-tyrosine kinase of the Eph subclass, containing all conserved amino acid residues in the catalytic domain of protein-tyrosine kinases, and is most highly expressed in brain.\",\n      \"method\": \"cDNA cloning, Northern blot analysis\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cDNA cloning with sequence analysis and Northern blot, single lab, two orthogonal methods establishing identity and expression\",\n      \"pmids\": [\"1648701\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"EphA8 (Eek) knockout mice show aberrant axonal projections: tectal neurons in the superior colliculus fail to reach contralateral inferior colliculus targets, and an abnormal ipsilateral tract projects to ventral cervical spinal cord, establishing EphA8 as required for axonal pathfinding in the mammalian nervous system.\",\n      \"method\": \"Homologous recombination knockout, axonal tracing (anterograde and retrograde labeling)\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean germline knockout with two orthogonal axonal tracing methods establishing specific pathfinding phenotype\",\n      \"pmids\": [\"9214628\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"EphA8 (Eek) receptor can be activated by at least three GPI-linked ephrin-A ligands (Elf-1/Cek7-L, Ehk1-L/Efl-2/Lerk3, and AL-1/RAGS), which bind to and tyrosine-phosphorylate EphA8 expressed in NIH3T3 cells.\",\n      \"method\": \"Chimeric Fc-fusion ligand binding assays, receptor phosphorylation assays in transfected NIH3T3 cells\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ligand binding and receptor activation confirmed with chimeric proteins, single lab, two orthogonal methods\",\n      \"pmids\": [\"9053851\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Tyr-615 (juxtamembrane) and Tyr-838 (kinase domain) are major autophosphorylation sites of EphA8. Mutation of Tyr-838 drastically reduces catalytic activity. Phospho-Tyr-615 selectively mediates binding to the Fyn SH2 domain over Src and RasGAP SH2 domains. Mutation of either site reduces EphA8-Fyn association in intact cells and attenuates cell attachment responses.\",\n      \"method\": \"2D phosphopeptide mapping, in vitro kinase assay, site-directed mutagenesis, in vitro SH2 binding, co-immunoprecipitation\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro kinase assay with mutagenesis, 2D phosphopeptide mapping, and Co-IP, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"10498895\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"EphA8 binds and is activated by ephrin-A1 and ephrin-A4 (GPI-linked), but not transmembrane ephrin-B1, -B2, or -B3, confirming EphA8 functions exclusively as a GPI-linked ephrin-A-dependent receptor tyrosine kinase.\",\n      \"method\": \"Chimeric Fc-fusion ligand binding assay, receptor tyrosine phosphorylation in transfected NIH3T3 fibroblasts\",\n      \"journal\": \"Molecules and cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ligand binding and phosphorylation assays with panel of ephrin-Fc chimeras, single lab\",\n      \"pmids\": [\"10515610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"EphA8 promotes cell adhesion to fibronectin via alpha5beta1 or beta3 integrins in a tyrosine kinase-independent manner. This function requires ephrin-A binding to the extracellular domain and the juxtamembrane intracellular segment. EphA8 associates with the p110gamma isoform of PI 3-kinase via its juxtamembrane segment, and p110gamma lipid kinase activity is required for integrin-mediated cell adhesion.\",\n      \"method\": \"Cell adhesion assay, kinase-inactive mutant analysis, EphA8 deletion/point mutants, PI 3-kinase activity assay, in vitro pulldown, dominant-negative p110gamma lipid kinase-inactive mutant\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro binding, mutagenesis, kinase assay, and cell adhesion phenotype with dominant-negative, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"11416136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"EphA8-stimulated cell migration on fibronectin requires p110gamma PI 3-kinase activity. Ephrin-A5 stimulation increases stability of the p110gamma–EphA8 complex and enhances PI 3-kinase activity. A lipid kinase-inactive p110gamma dominantly suppresses EphA8-stimulated migration. EphA8 tyrosine kinase activity is dispensable for this process.\",\n      \"method\": \"PI 3-kinase activity assay, dominant-negative lipid kinase-inactive p110gamma mutant, cell migration assay on fibronectin\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional migration assay with dominant-negative mutant and kinase assay, single lab\",\n      \"pmids\": [\"12681484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"EphA8 directly phosphorylates and activates low molecular weight phosphotyrosine protein phosphatase (LMW-PTP) in vitro, and the phosphorylated LMW-PTP in turn dephosphorylates EphA8, suggesting a feedback-control mechanism of EphA8 autokinase activity.\",\n      \"method\": \"In vitro kinase assay, in vitro phosphatase activity assay\",\n      \"journal\": \"Journal of biochemistry and molecular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro reconstitution with two enzymes, single lab, single study\",\n      \"pmids\": [\"12787484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"EphA8 induces sustained MAP kinase (MAPK/ERK) activation and nuclear relocalization of activated MAPK, driving neurite outgrowth in NG108-15 neuronal cells. This requires the tyrosine kinase domain but not kinase catalytic activity, and is independent of ligand stimulation.\",\n      \"method\": \"Deletion mutant analysis, MAPK activity assay, immunofluorescence localization, kinase inhibitors, neurite outgrowth assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — deletion mutants, pharmacological inhibition, and kinase activity assay, single lab\",\n      \"pmids\": [\"15782114\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"The PTB domain-containing proteins AIDA-1b and Odin (Anks family) associate with the juxtamembrane domain of EphA8 in response to ephrin-A5 ligand stimulation. This interaction is independent of EphA8 tyrosine kinase activity. Odin is identified as the more physiologically relevant partner; siRNA-mediated Odin knockdown diminishes EphA8-mediated inhibition of cell migration and neurite retraction. Overexpression of the Odin PTB domain alone (dominant-negative) attenuates EphA8-mediated cell migration inhibition.\",\n      \"method\": \"Co-immunoprecipitation, PTB domain pulldown, siRNA knockdown, dominant-negative overexpression, cell migration assay, neurite retraction assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP, dominant-negative, and siRNA knockdown with multiple cellular phenotype readouts, single lab\",\n      \"pmids\": [\"17875921\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"EphA8 undergoes clathrin-mediated endocytosis upon ephrin-A5 stimulation. The juxtamembrane region of EphA8 is required for endocytosis of EphA8-ephrinA5 complexes and for association with Tiam-1, a Rac-specific GEF. Tiam-1 knockdown impairs endocytosis of EphA8-ephrinA5 complexes, and an endocytosis-defective EphA8 juxtamembrane mutant shows reduced Rac activation after ephrin-A5 stimulation.\",\n      \"method\": \"Endocytosis assay, EphA8 deletion mutant analysis, Co-immunoprecipitation, siRNA knockdown of Tiam-1, Rac activity assay\",\n      \"journal\": \"Molecules and cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — deletion mutants, Co-IP, siRNA knockdown with endocytosis and Rac activation readouts, single lab\",\n      \"pmids\": [\"20496116\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"RINL (a Rab5-subfamily GEF) interacts with Odin and forms a ternary complex with EphA8. RINL expression reduces EphA8 protein levels in a manner dependent on its GEF activity and interaction with Odin; RINL knockdown increases EphA8 levels, placing RINL in the EphA8 degradation pathway via the endosomal/Rab5 system.\",\n      \"method\": \"Co-immunoprecipitation, GTP-bound Rab5 assay, RINL knockdown, RINL overexpression with GEF-inactive mutant, Western blot for EphA8 levels\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, GEF activity assay, and siRNA knockdown with receptor level readout, single lab\",\n      \"pmids\": [\"22291991\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Ectopic expression of EphA8-Fc in transgenic mouse embryos induces caspase-dependent apoptosis of ephrin-A5-expressing neural epithelial cells, causing a dramatic decrease in brain size, indicating that EphA8 can drive reverse signaling through ephrin-As to activate proapoptotic pathways during brain development.\",\n      \"method\": \"Transgenic mouse ectopic expression, in vivo and in vitro apoptosis assay, caspase inhibitor treatment, neuroepithelial cell culture\",\n      \"journal\": \"Developmental neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — transgenic in vivo model and in vitro cell culture with caspase inhibitor, single lab\",\n      \"pmids\": [\"23696555\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In human rhabdomyosarcoma cells, ephrin-A5 binds and signals through EphA8 (not EphA7), and this signaling inhibits cell proliferation, identifying EphA8 as the relevant receptor for ephrin-A5-mediated anti-proliferative effects in this context.\",\n      \"method\": \"Binding assay with Fc chimeras, signaling assay, cell proliferation assay in human RMS cell lines\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — preprint, single lab, single binding/functional assay, limited mechanistic detail in abstract\",\n      \"pmids\": [\"bio_10.1101_2024.12.23.629471\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"EphA8 is an Eph-family receptor tyrosine kinase that binds multiple GPI-linked ephrin-A ligands (A1–A5) and signals through both kinase-dependent and kinase-independent mechanisms: ligand-independent, it drives sustained MAPK activation and neurite outgrowth; ligand-stimulated, it recruits p110gamma PI3K via its juxtamembrane domain (kinase-independently) to promote integrin-mediated adhesion and cell migration on fibronectin, recruits Odin/AIDA-1b PTB-domain scaffolds to inhibit cell migration, undergoes Tiam-1-dependent clathrin-mediated endocytosis coupled to Rac activation, and is targeted for degradation via a RINL–Odin–Rab5 axis; autophosphorylation at Tyr-838 sustains catalytic activity while pTyr-615 recruits Fyn kinase, and EphA8 also phosphorylates and activates LMW-PTP in a feedback loop; in vivo, EphA8 is required for axonal pathfinding in the superior colliculus and, through reverse signaling via ephrin-A5, regulates neural epithelial cell survival during brain development.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"EphA8 is an Eph-subclass receptor protein-tyrosine kinase, most highly expressed in brain, that governs axonal pathfinding and developmental cell-fate decisions in the mammalian nervous system [#0, #1]. It functions as a GPI-linked ephrin-A-selective receptor, binding and being tyrosine-phosphorylated by ephrin-A ligands (A1, A4, A5) but not transmembrane ephrin-B ligands [#2, #4]. Its juxtamembrane segment is a central signaling hub: it carries the autophosphorylation site Tyr-615 that selectively recruits Fyn, while Tyr-838 in the kinase domain sustains catalytic activity [#3]. Strikingly, several EphA8 outputs are kinase-independent — ligand-engaged EphA8 recruits the p110gamma isoform of PI 3-kinase through its juxtamembrane segment to drive integrin-mediated adhesion and migration on fibronectin [#5, #6], and the kinase domain (but not its catalytic activity) is required for sustained MAPK activation and neurite outgrowth [#8]. The same juxtamembrane region nucleates ligand-dependent recruitment of the Anks-family PTB scaffolds Odin and AIDA-1b, which restrain cell migration and promote neurite retraction [#9], and couples receptor activation to Tiam-1-dependent, clathrin-mediated endocytosis and Rac activation [#10]; receptor turnover is further controlled by the Rab5 GEF RINL acting through Odin [#11]. EphA8 also engages a phosphatase feedback loop by phosphorylating and activating LMW-PTP, which in turn dephosphorylates the receptor [#7]. Beyond forward signaling, EphA8 can drive reverse signaling through ephrin-A5 to trigger caspase-dependent apoptosis of neural epithelial cells during brain development [#12].\",\n  \"teleology\": [\n    {\n      \"year\": 1991,\n      \"claim\": \"Established the molecular identity of EphA8 as a brain-enriched Eph-family receptor tyrosine kinase, defining the protein class before any function was known.\",\n      \"evidence\": \"cDNA cloning and sequence analysis with Northern blot expression profiling\",\n      \"pmids\": [\"1648701\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No ligand identified\", \"No in vivo function established\", \"Catalytic activity inferred from sequence, not demonstrated\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Defined the in vivo requirement for EphA8, showing it is needed for correct axonal pathfinding rather than serving a dispensable role.\",\n      \"evidence\": \"Germline knockout mouse with anterograde and retrograde axonal tracing in the superior colliculus\",\n      \"pmids\": [\"9214628\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the ligand or downstream effectors mediating pathfinding\", \"Cell-autonomy of the defect not resolved\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Identified the activating ligands, establishing that EphA8 is engaged and phosphorylated by GPI-linked ephrin-A ligands.\",\n      \"evidence\": \"Fc-fusion ligand binding and receptor phosphorylation assays in transfected NIH3T3 cells\",\n      \"pmids\": [\"9053851\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ligand selectivity versus ephrin-B not yet tested\", \"Downstream signaling not addressed\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Confirmed exclusive ephrin-A (GPI-linked) ligand selectivity, ruling out transmembrane ephrin-B ligands.\",\n      \"evidence\": \"Ephrin-Fc chimera panel binding and receptor phosphorylation in NIH3T3 fibroblasts\",\n      \"pmids\": [\"10515610\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological ligand in vivo not pinpointed\", \"Affinities not quantified\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Mapped the key autophosphorylation sites and linked them to specific outputs, distinguishing a catalytic-sustaining site from an SH2-docking site.\",\n      \"evidence\": \"2D phosphopeptide mapping, in vitro kinase assay, mutagenesis, in vitro SH2 binding, and Co-IP\",\n      \"pmids\": [\"10498895\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of Fyn recruitment downstream not detailed\", \"Stoichiometry of phosphorylation in vivo unknown\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Revealed a kinase-independent adhesion mechanism in which EphA8 recruits p110gamma PI 3-kinase via its juxtamembrane segment to drive integrin-mediated adhesion.\",\n      \"evidence\": \"Cell adhesion assays with kinase-inactive and deletion mutants, in vitro pulldown, and dominant-negative lipid kinase-dead p110gamma\",\n      \"pmids\": [\"11416136\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the p110gamma juxtamembrane interaction not resolved\", \"In vivo relevance of the adhesion role untested\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Extended the p110gamma axis to cell migration, showing ligand stabilizes the complex and that lipid kinase activity, not EphA8 catalysis, drives motility.\",\n      \"evidence\": \"PI 3-kinase activity assay, dominant-negative lipid kinase-dead p110gamma, and fibronectin migration assay\",\n      \"pmids\": [\"12681484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Downstream effectors of p110gamma in migration not identified\", \"Connection to integrin signaling not mechanistically closed\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Uncovered a phosphatase feedback loop in which EphA8 activates LMW-PTP, which then dephosphorylates the receptor.\",\n      \"evidence\": \"In vitro kinase and phosphatase activity assays with purified enzymes\",\n      \"pmids\": [\"12787484\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vitro reconstitution only; cellular relevance not established\", \"Effect on downstream signaling not measured\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Demonstrated a ligand- and catalysis-independent route to sustained MAPK signaling and neurite outgrowth requiring the kinase domain as a scaffold.\",\n      \"evidence\": \"Deletion mutants, kinase inhibitors, MAPK activity assay, and neurite outgrowth assay in NG108-15 cells\",\n      \"pmids\": [\"15782114\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Adaptors linking the kinase domain to MAPK not identified\", \"Reconciliation with kinase-dependent outputs unresolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Identified Odin/AIDA-1b PTB scaffolds as ligand-induced juxtamembrane partners that restrain migration and promote neurite retraction, defining an inhibitory branch of signaling.\",\n      \"evidence\": \"Reciprocal Co-IP, PTB-domain pulldown, siRNA knockdown, dominant-negative PTB overexpression, and migration/retraction assays\",\n      \"pmids\": [\"17875921\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream effectors of Odin in EphA8 inhibition unmapped\", \"Interplay with the p110gamma promigratory branch unclear\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Linked receptor activation to clathrin-mediated endocytosis and Rac activation through juxtamembrane recruitment of the GEF Tiam-1.\",\n      \"evidence\": \"Endocytosis and Rac activity assays, deletion mutants, Co-IP, and Tiam-1 knockdown\",\n      \"pmids\": [\"20496116\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether endocytosis terminates or propagates signaling not resolved\", \"In vivo role of EphA8 internalization untested\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Placed EphA8 in a degradative pathway, showing the Rab5 GEF RINL acts via Odin to lower receptor levels.\",\n      \"evidence\": \"Co-IP, GTP-Rab5 assay, RINL knockdown/overexpression with GEF-inactive mutant, and EphA8 Western blots\",\n      \"pmids\": [\"22291991\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Lysosomal versus proteasomal fate not distinguished\", \"Physiological context of receptor turnover unknown\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Showed EphA8 can act as a ligand for reverse signaling, driving caspase-dependent apoptosis of ephrin-A5-expressing neural epithelium during brain development.\",\n      \"evidence\": \"Transgenic embryo ectopic EphA8-Fc expression, in vivo/in vitro apoptosis assays, and caspase inhibition\",\n      \"pmids\": [\"23696555\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ephrin-A5 reverse-signaling effectors not identified\", \"Relevance to endogenous EphA8 spatial gradients unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Implicated EphA8 as the relevant ephrin-A5 receptor mediating anti-proliferative signaling in human rhabdomyosarcoma cells.\",\n      \"evidence\": \"Fc-chimera binding, signaling, and proliferation assays in RMS cell lines (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.12.23.629471\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Preprint, single lab with limited mechanistic detail\", \"Signaling pathway driving growth arrest not defined\", \"In vivo tumor relevance untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the competing promigratory (p110gamma/Tiam-1/Rac) and antimigratory (Odin) branches are integrated downstream of a single juxtamembrane hub, and how kinase-dependent and kinase-independent outputs are coordinated in vivo, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the juxtamembrane signaling complex\", \"No in vivo dissection of which downstream branch mediates the axonal pathfinding phenotype\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [3, 7]},\n      {\"term_id\": \"GO:0004672\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0001618\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [2, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [5, 10]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [10, 11]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [3, 5, 8]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [1, 12]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [10, 11]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [12]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"EFNA5\", \"PIK3CG\", \"FYN\", \"ANKS1A\", \"ANKS1B\", \"TIAM1\", \"RINL\", \"ACP1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}