{"gene":"ACAP3","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":2016,"finding":"ACAP3 functions as a GTPase-activating protein (GAP) specific to Arf6 and positively regulates neurite outgrowth in mouse hippocampal neurons; knockdown of ACAP3 increased GTP-bound Arf6 levels and abrogated neurite outgrowth, which was rescued by wild-type ACAP3 but not by a GAP-inactive mutant, demonstrating that catalytic GAP activity is required. Cycling between active and inactive Arf6 states (rather than constitutive GTP- or GDP-bound Arf6) was shown to be required for neurite outgrowth.","method":"Primary hippocampal neuron knockdown/knockout, ectopic expression of wild-type vs. GAP-inactive mutant ACAP3, GTP-bound Arf6 pulldown assay, in vitro GAP activity assay in HEK-293T cells","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1–2 — in vitro GAP assay + mutagenesis + primary neuron KD/KO with specific phenotypic rescue, Moderate-to-Strong evidence from single lab with multiple orthogonal methods","pmids":["27330119"],"is_preprint":false},{"year":2017,"finding":"ACAP3, acting through its Arf6-specific GAP activity, is required for neuronal migration in the developing mouse cerebral cortex in vivo; in utero knockdown of ACAP3 impaired cortical neuron migration and morphological changes during migration, and rescue required GAP-competent ACAP3 but not the GAP-inactive mutant.","method":"In utero electroporation knockdown in mouse cortex, ectopic expression of wild-type vs. GAP-inactive ACAP3 mutant, cortical layer migration analysis","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 2 — in vivo epistasis with GAP-inactive mutant rescue experiment confirming mechanistic requirement, single lab but rigorous genetic approach","pmids":["28919417"],"is_preprint":false},{"year":2024,"finding":"HDAC2 negatively regulates ACAP3 expression in papillary thyroid carcinoma cells; ACAP3 overexpression suppressed cell viability, migration, invasion, and EMT markers (downregulating Bcl-2 and N-cadherin, upregulating Bax and E-cadherin), reduced p-AKT/AKT ratio, and elevated p-p53/p53 ratio, while HDAC2 overexpression reversed these effects, placing ACAP3 downstream of HDAC2 in the AKT/p53 signaling axis.","method":"qRT-PCR, Western blot, cell functional assays (CCK-8, transwell, wound healing, flow cytometry), Pearson correlation analysis, rescue assay with oe-ACAP3 + oe-HDAC2","journal":"The international journal of biochemistry & cell biology","confidence":"Medium","confidence_rationale":"Tier 3 — single lab, multiple functional assays but no direct biochemical demonstration of HDAC2 acting on ACAP3 promoter/chromatin","pmids":["39098591"],"is_preprint":false},{"year":2026,"finding":"ACAP3 inhibits EGFR signaling in lung adenocarcinoma by impairing EGFR recycling and accelerating lysosome-mediated EGFR degradation in a GAP-activity-dependent manner; Myc-mediated DNA hypermethylation and deacetylation suppress ACAP3 expression, and ACAP3 suppresses LUAD cell proliferation in vitro and in vivo.","method":"RRBS DNA methylation profiling, in vitro and in vivo proliferation assays, EGFR trafficking/recycling assays, GAP-activity-dependent rescue experiments","journal":"British journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 — GAP-activity-dependent mechanism with EGFR trafficking readout, single lab but multiple orthogonal methods including in vivo","pmids":["41520057"],"is_preprint":false},{"year":2010,"finding":"The intronic minisatellite UPS29 of the ACAP3 (CENTB5) gene possesses enhancer-like activity that is cell-type specific, upregulating reporter gene (EGFP) expression preferentially in neuronal-type cells (rat astrocytes and mouse F9 embryonal carcinoma cells) compared to HeLa cells.","method":"Transient transfection of EGFP reporter plasmids containing different UPS29 alleles into HeLa, F9, and rat astrocyte cell lines","journal":"Tsitologiia","confidence":"Low","confidence_rationale":"Tier 3 — single lab, reporter assay without direct mechanistic follow-up on ACAP3 protein function","pmids":["21105360"],"is_preprint":false}],"current_model":"ACAP3 is an ArfGAP that specifically inactivates Arf6 (by stimulating GTP hydrolysis), and this GAP activity is required for neurite outgrowth and cortical neuron migration in the developing brain; in cancer contexts, ACAP3 acts as a tumor suppressor by inhibiting EGFR recycling and promoting lysosomal EGFR degradation in a GAP-activity-dependent manner, while its expression is epigenetically silenced by HDAC2 (in thyroid cancer) and Myc-mediated DNA methylation/deacetylation (in lung adenocarcinoma)."},"narrative":{"teleology":[{"year":2010,"claim":"An intronic minisatellite (UPS29) within the ACAP3 locus was shown to have cell-type-specific enhancer activity favoring neuronal lineages, providing the first hint that ACAP3 expression is subject to tissue-specific cis-regulatory control.","evidence":"Reporter (EGFP) assays in HeLa, F9 embryonal carcinoma, and rat astrocyte cell lines","pmids":["21105360"],"confidence":"Low","gaps":["Reporter assay only; no demonstration that UPS29 regulates endogenous ACAP3 transcription","No chromatin context or transcription factor binding data provided","Functional relevance of different UPS29 allele lengths not established"]},{"year":2016,"claim":"Establishing the core enzymatic identity of ACAP3: it was demonstrated to be an Arf6-specific GAP whose catalytic activity is required for neurite outgrowth, resolving the question of which Arf family member ACAP3 acts on and linking its biochemical function to a developmental process.","evidence":"In vitro GAP assay, GTP-Arf6 pulldown, knockdown and rescue with wild-type vs. GAP-inactive mutant in primary mouse hippocampal neurons","pmids":["27330119"],"confidence":"High","gaps":["Direct structural basis for Arf6 specificity over other Arfs not determined","Downstream effectors linking Arf6 cycling to neurite extension not identified","Limited to cultured hippocampal neurons; in vivo relevance not yet shown"]},{"year":2017,"claim":"The requirement for ACAP3 GAP activity was extended to an in vivo developmental process—cortical neuron migration—demonstrating that ACAP3-mediated Arf6 inactivation is essential for proper neuronal positioning in the cerebral cortex.","evidence":"In utero electroporation knockdown and GAP-mutant rescue in developing mouse cortex with cortical layer migration analysis","pmids":["28919417"],"confidence":"High","gaps":["Specific membrane trafficking step regulated by ACAP3/Arf6 during migration not identified","No conditional knockout to assess postnatal or adult neuronal functions","Whether ACAP3 loss causes neurodevelopmental disease in humans is unknown"]},{"year":2024,"claim":"ACAP3 was placed downstream of HDAC2-mediated epigenetic silencing in thyroid cancer, revealing that its tumor-suppressive effects—inhibiting proliferation, migration, and EMT—operate through modulation of AKT and p53 signaling.","evidence":"Overexpression/rescue experiments with HDAC2 and ACAP3 in papillary thyroid carcinoma cell lines, Western blot for AKT/p53 pathway components","pmids":["39098591"],"confidence":"Medium","gaps":["No direct evidence that HDAC2 acts on the ACAP3 promoter (e.g., ChIP)","Whether AKT/p53 effects are mediated through Arf6 GAP activity is untested","Single cancer type; generalizability of the HDAC2-ACAP3 axis is unclear"]},{"year":2026,"claim":"The mechanism of ACAP3 tumor suppression was resolved at the receptor trafficking level: ACAP3 impairs EGFR recycling and promotes its lysosomal degradation in a GAP-activity-dependent manner, while Myc-driven epigenetic silencing (DNA methylation and deacetylation) explains ACAP3 loss in lung adenocarcinoma.","evidence":"RRBS methylation profiling, EGFR recycling/trafficking assays, GAP-mutant rescue, in vivo xenograft proliferation assays in LUAD models","pmids":["41520057"],"confidence":"Medium","gaps":["Whether Arf6 directly controls the EGFR recycling endosome in this context needs reconstitution","Structural basis of ACAP3 interaction with EGFR-containing compartments is unknown","Therapeutic relevance of re-expressing ACAP3 (e.g., via HDAC or DNMT inhibition) not tested in vivo"]},{"year":null,"claim":"Key unresolved questions include the structural basis of ACAP3 Arf6 specificity, the identity of direct downstream effectors linking Arf6 cycling to neurite outgrowth and cell migration, whether ACAP3 loss-of-function causes human neurodevelopmental disorders, and whether the neuronal and cancer trafficking functions converge on a shared Arf6-dependent membrane compartment.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of ACAP3 catalytic domain with Arf6","No human genetic disease association established by direct evidence","Whether neuronal and EGFR-trafficking functions share an identical Arf6-dependent mechanism is unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,3]}],"localization":[{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[3]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,3]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,1]}],"complexes":[],"partners":["ARF6","EGFR","HDAC2"],"other_free_text":[]},"mechanistic_narrative":"ACAP3 is an Arf6-specific GTPase-activating protein (ArfGAP) that controls membrane trafficking events critical for neuronal development and receptor homeostasis. Its catalytic GAP activity, which promotes GTP hydrolysis on Arf6, is required for neurite outgrowth in hippocampal neurons and for radial migration of cortical neurons during brain development, with cycling between active and inactive Arf6 states—rather than constitutive locking in either state—being essential [PMID:27330119, PMID:28919417]. In lung adenocarcinoma, ACAP3 functions as a tumor suppressor by impairing EGFR recycling and directing EGFR to lysosomal degradation in a GAP-activity-dependent manner, thereby attenuating EGFR signaling; its expression is epigenetically silenced by Myc-driven DNA methylation and histone deacetylation, and separately by HDAC2 in papillary thyroid carcinoma [PMID:41520057, PMID:39098591]."},"prefetch_data":{"uniprot":{"accession":"Q96P50","full_name":"Arf-GAP with coiled-coil, ANK repeat and PH domain-containing protein 3","aliases":["Centaurin-beta-5","Cnt-b5"],"length_aa":834,"mass_kda":92.5,"function":"GTPase-activating protein for the ADP ribosylation factor family","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/Q96P50/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ACAP3","classification":"Not Classified","n_dependent_lines":20,"n_total_lines":1208,"dependency_fraction":0.016556291390728478},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000131584","cell_line_id":"CID000675","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"big_aggregates","grade":2},{"compartment":"mitochondria","grade":2}],"interactors":[{"gene":"ACAP2","stoichiometry":4.0}],"url":"https://opencell.sf.czbiohub.org/target/CID000675","total_profiled":1310},"omim":[],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Golgi apparatus","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":155.0}],"url":"https://www.proteinatlas.org/search/ACAP3"},"hgnc":{"alias_symbol":["KIAA1716"],"prev_symbol":["CENTB5"]},"alphafold":{"accession":"Q96P50","domains":[{"cath_id":"1.20.1270.60","chopping":"6-247","consensus_level":"high","plddt":94.368,"start":6,"end":247},{"cath_id":"2.30.29.30","chopping":"270-368","consensus_level":"high","plddt":86.264,"start":270,"end":368},{"cath_id":"1.10.220.150","chopping":"416-514","consensus_level":"high","plddt":89.7595,"start":416,"end":514}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96P50","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96P50-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96P50-F1-predicted_aligned_error_v6.png","plddt_mean":75.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ACAP3","jax_strain_url":"https://www.jax.org/strain/search?query=ACAP3"},"sequence":{"accession":"Q96P50","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96P50.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96P50/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96P50"}},"corpus_meta":[{"pmid":"33540684","id":"PMC_33540684","title":"Analysis of m6A RNA Methylation-Related Genes in Liver Hepatocellular Carcinoma and Their Correlation with Survival.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/33540684","citation_count":53,"is_preprint":false},{"pmid":"37464898","id":"PMC_37464898","title":"Aging Differentially Affects Axonal Autophagosome Formation and Maturation.","date":"2023","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/37464898","citation_count":22,"is_preprint":false},{"pmid":"29491472","id":"PMC_29491472","title":"Integrative functional analysis of super enhancer SNPs for coronary artery disease.","date":"2018","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/29491472","citation_count":22,"is_preprint":false},{"pmid":"27330119","id":"PMC_27330119","title":"ACAP3 regulates neurite outgrowth through its GAP activity specific to Arf6 in mouse hippocampal neurons.","date":"2016","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/27330119","citation_count":17,"is_preprint":false},{"pmid":"28919417","id":"PMC_28919417","title":"ACAP3, the GTPase-activating protein specific to the small GTPase Arf6, regulates neuronal migration in the developing cerebral cortex.","date":"2017","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/28919417","citation_count":9,"is_preprint":false},{"pmid":"38093298","id":"PMC_38093298","title":"Identification and validation of eight lysosomes-related genes signatures and correlation with immune cell infiltration in lung adenocarcinoma.","date":"2023","source":"Cancer cell international","url":"https://pubmed.ncbi.nlm.nih.gov/38093298","citation_count":9,"is_preprint":false},{"pmid":"38723630","id":"PMC_38723630","title":"Cis- and trans-eQTL TWASs of breast and ovarian cancer identify more than 100 susceptibility genes in the BCAC and OCAC consortia.","date":"2024","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/38723630","citation_count":9,"is_preprint":false},{"pmid":"33276684","id":"PMC_33276684","title":"Length Polymorphism and Methylation Status of UPS29 Minisatellite of the ACAP3 Gene as Molecular Biomarker of Epilepsy. Sex Differences in Seizure Types and Symptoms.","date":"2020","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/33276684","citation_count":7,"is_preprint":false},{"pmid":"39098591","id":"PMC_39098591","title":"ACAP3 negatively regulated by HDAC2 inhibits the malignant development of papillary thyroid carcinoma cells.","date":"2024","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/39098591","citation_count":2,"is_preprint":false},{"pmid":"23657595","id":"PMC_23657595","title":"The expression and phylogenetic analysis of four AP3-like paralogs in the stamens, carpels, and single-whorl perianth of the paleoherb Asarum caudigerum.","date":"2013","source":"Molecular biology reports","url":"https://pubmed.ncbi.nlm.nih.gov/23657595","citation_count":2,"is_preprint":false},{"pmid":"38014246","id":"PMC_38014246","title":"Cis- and trans-eQTL TWAS of breast and ovarian cancer identify more than 100 risk associated genes in the BCAC and OCAC consortia.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/38014246","citation_count":2,"is_preprint":false},{"pmid":"21105360","id":"PMC_21105360","title":"[Human intra-intronic minisatellite UPS29 associated with neurological diseases regulates reporter gene EGFP expression depending on cell type].","date":"2010","source":"Tsitologiia","url":"https://pubmed.ncbi.nlm.nih.gov/21105360","citation_count":1,"is_preprint":false},{"pmid":"41520057","id":"PMC_41520057","title":"Myc-mediated epigenetic silencing of ACAP3 promotes lung adenocarcinoma proliferation via regulating EGFR dynamics.","date":"2026","source":"British journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/41520057","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8245,"output_tokens":1561,"usd":0.024075},"stage2":{"model":"claude-opus-4-6","input_tokens":4780,"output_tokens":1865,"usd":0.105788},"total_usd":0.129863,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"ACAP3 functions as a GTPase-activating protein (GAP) specific to Arf6 and positively regulates neurite outgrowth in mouse hippocampal neurons; knockdown of ACAP3 increased GTP-bound Arf6 levels and abrogated neurite outgrowth, which was rescued by wild-type ACAP3 but not by a GAP-inactive mutant, demonstrating that catalytic GAP activity is required. Cycling between active and inactive Arf6 states (rather than constitutive GTP- or GDP-bound Arf6) was shown to be required for neurite outgrowth.\",\n      \"method\": \"Primary hippocampal neuron knockdown/knockout, ectopic expression of wild-type vs. GAP-inactive mutant ACAP3, GTP-bound Arf6 pulldown assay, in vitro GAP activity assay in HEK-293T cells\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — in vitro GAP assay + mutagenesis + primary neuron KD/KO with specific phenotypic rescue, Moderate-to-Strong evidence from single lab with multiple orthogonal methods\",\n      \"pmids\": [\"27330119\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"ACAP3, acting through its Arf6-specific GAP activity, is required for neuronal migration in the developing mouse cerebral cortex in vivo; in utero knockdown of ACAP3 impaired cortical neuron migration and morphological changes during migration, and rescue required GAP-competent ACAP3 but not the GAP-inactive mutant.\",\n      \"method\": \"In utero electroporation knockdown in mouse cortex, ectopic expression of wild-type vs. GAP-inactive ACAP3 mutant, cortical layer migration analysis\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — in vivo epistasis with GAP-inactive mutant rescue experiment confirming mechanistic requirement, single lab but rigorous genetic approach\",\n      \"pmids\": [\"28919417\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"HDAC2 negatively regulates ACAP3 expression in papillary thyroid carcinoma cells; ACAP3 overexpression suppressed cell viability, migration, invasion, and EMT markers (downregulating Bcl-2 and N-cadherin, upregulating Bax and E-cadherin), reduced p-AKT/AKT ratio, and elevated p-p53/p53 ratio, while HDAC2 overexpression reversed these effects, placing ACAP3 downstream of HDAC2 in the AKT/p53 signaling axis.\",\n      \"method\": \"qRT-PCR, Western blot, cell functional assays (CCK-8, transwell, wound healing, flow cytometry), Pearson correlation analysis, rescue assay with oe-ACAP3 + oe-HDAC2\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single lab, multiple functional assays but no direct biochemical demonstration of HDAC2 acting on ACAP3 promoter/chromatin\",\n      \"pmids\": [\"39098591\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"ACAP3 inhibits EGFR signaling in lung adenocarcinoma by impairing EGFR recycling and accelerating lysosome-mediated EGFR degradation in a GAP-activity-dependent manner; Myc-mediated DNA hypermethylation and deacetylation suppress ACAP3 expression, and ACAP3 suppresses LUAD cell proliferation in vitro and in vivo.\",\n      \"method\": \"RRBS DNA methylation profiling, in vitro and in vivo proliferation assays, EGFR trafficking/recycling assays, GAP-activity-dependent rescue experiments\",\n      \"journal\": \"British journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — GAP-activity-dependent mechanism with EGFR trafficking readout, single lab but multiple orthogonal methods including in vivo\",\n      \"pmids\": [\"41520057\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"The intronic minisatellite UPS29 of the ACAP3 (CENTB5) gene possesses enhancer-like activity that is cell-type specific, upregulating reporter gene (EGFP) expression preferentially in neuronal-type cells (rat astrocytes and mouse F9 embryonal carcinoma cells) compared to HeLa cells.\",\n      \"method\": \"Transient transfection of EGFP reporter plasmids containing different UPS29 alleles into HeLa, F9, and rat astrocyte cell lines\",\n      \"journal\": \"Tsitologiia\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single lab, reporter assay without direct mechanistic follow-up on ACAP3 protein function\",\n      \"pmids\": [\"21105360\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ACAP3 is an ArfGAP that specifically inactivates Arf6 (by stimulating GTP hydrolysis), and this GAP activity is required for neurite outgrowth and cortical neuron migration in the developing brain; in cancer contexts, ACAP3 acts as a tumor suppressor by inhibiting EGFR recycling and promoting lysosomal EGFR degradation in a GAP-activity-dependent manner, while its expression is epigenetically silenced by HDAC2 (in thyroid cancer) and Myc-mediated DNA methylation/deacetylation (in lung adenocarcinoma).\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ACAP3 is an Arf6-specific GTPase-activating protein (ArfGAP) that controls membrane trafficking events critical for neuronal development and receptor homeostasis. Its catalytic GAP activity, which promotes GTP hydrolysis on Arf6, is required for neurite outgrowth in hippocampal neurons and for radial migration of cortical neurons during brain development, with cycling between active and inactive Arf6 states—rather than constitutive locking in either state—being essential [PMID:27330119, PMID:28919417]. In lung adenocarcinoma, ACAP3 functions as a tumor suppressor by impairing EGFR recycling and directing EGFR to lysosomal degradation in a GAP-activity-dependent manner, thereby attenuating EGFR signaling; its expression is epigenetically silenced by Myc-driven DNA methylation and histone deacetylation, and separately by HDAC2 in papillary thyroid carcinoma [PMID:41520057, PMID:39098591].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"An intronic minisatellite (UPS29) within the ACAP3 locus was shown to have cell-type-specific enhancer activity favoring neuronal lineages, providing the first hint that ACAP3 expression is subject to tissue-specific cis-regulatory control.\",\n      \"evidence\": \"Reporter (EGFP) assays in HeLa, F9 embryonal carcinoma, and rat astrocyte cell lines\",\n      \"pmids\": [\"21105360\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Reporter assay only; no demonstration that UPS29 regulates endogenous ACAP3 transcription\",\n        \"No chromatin context or transcription factor binding data provided\",\n        \"Functional relevance of different UPS29 allele lengths not established\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Establishing the core enzymatic identity of ACAP3: it was demonstrated to be an Arf6-specific GAP whose catalytic activity is required for neurite outgrowth, resolving the question of which Arf family member ACAP3 acts on and linking its biochemical function to a developmental process.\",\n      \"evidence\": \"In vitro GAP assay, GTP-Arf6 pulldown, knockdown and rescue with wild-type vs. GAP-inactive mutant in primary mouse hippocampal neurons\",\n      \"pmids\": [\"27330119\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Direct structural basis for Arf6 specificity over other Arfs not determined\",\n        \"Downstream effectors linking Arf6 cycling to neurite extension not identified\",\n        \"Limited to cultured hippocampal neurons; in vivo relevance not yet shown\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"The requirement for ACAP3 GAP activity was extended to an in vivo developmental process—cortical neuron migration—demonstrating that ACAP3-mediated Arf6 inactivation is essential for proper neuronal positioning in the cerebral cortex.\",\n      \"evidence\": \"In utero electroporation knockdown and GAP-mutant rescue in developing mouse cortex with cortical layer migration analysis\",\n      \"pmids\": [\"28919417\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Specific membrane trafficking step regulated by ACAP3/Arf6 during migration not identified\",\n        \"No conditional knockout to assess postnatal or adult neuronal functions\",\n        \"Whether ACAP3 loss causes neurodevelopmental disease in humans is unknown\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"ACAP3 was placed downstream of HDAC2-mediated epigenetic silencing in thyroid cancer, revealing that its tumor-suppressive effects—inhibiting proliferation, migration, and EMT—operate through modulation of AKT and p53 signaling.\",\n      \"evidence\": \"Overexpression/rescue experiments with HDAC2 and ACAP3 in papillary thyroid carcinoma cell lines, Western blot for AKT/p53 pathway components\",\n      \"pmids\": [\"39098591\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct evidence that HDAC2 acts on the ACAP3 promoter (e.g., ChIP)\",\n        \"Whether AKT/p53 effects are mediated through Arf6 GAP activity is untested\",\n        \"Single cancer type; generalizability of the HDAC2-ACAP3 axis is unclear\"\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"The mechanism of ACAP3 tumor suppression was resolved at the receptor trafficking level: ACAP3 impairs EGFR recycling and promotes its lysosomal degradation in a GAP-activity-dependent manner, while Myc-driven epigenetic silencing (DNA methylation and deacetylation) explains ACAP3 loss in lung adenocarcinoma.\",\n      \"evidence\": \"RRBS methylation profiling, EGFR recycling/trafficking assays, GAP-mutant rescue, in vivo xenograft proliferation assays in LUAD models\",\n      \"pmids\": [\"41520057\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether Arf6 directly controls the EGFR recycling endosome in this context needs reconstitution\",\n        \"Structural basis of ACAP3 interaction with EGFR-containing compartments is unknown\",\n        \"Therapeutic relevance of re-expressing ACAP3 (e.g., via HDAC or DNMT inhibition) not tested in vivo\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of ACAP3 Arf6 specificity, the identity of direct downstream effectors linking Arf6 cycling to neurite outgrowth and cell migration, whether ACAP3 loss-of-function causes human neurodevelopmental disorders, and whether the neuronal and cancer trafficking functions converge on a shared Arf6-dependent membrane compartment.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural model of ACAP3 catalytic domain with Arf6\",\n        \"No human genetic disease association established by direct evidence\",\n        \"Whether neuronal and EGFR-trafficking functions share an identical Arf6-dependent mechanism is unknown\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"ARF6\",\n      \"EGFR\",\n      \"HDAC2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}