{"gene":"MAP7D1","run_date":"2026-06-10T02:59:50","timeline":{"discoveries":[{"year":2016,"finding":"DCLK1 directly phosphorylates MAP7D1 at serine 315 to promote axon elongation in cortical neurons. Knockdown of MAP7D1 impairs callosal axon elongation but not radial migration; overexpression of a phosphomimetic MAP7D1 S315E mutant rescues axon elongation defects in Dclk1 knockdown neurons, whereas wild-type MAP7D1 does not.","method":"Proteomic identification of DCLK1 substrate; in vitro phosphorylation assay; phosphomimetic/phosphodead mutagenesis; in utero electroporation knockdown with rescue experiments","journal":"Developmental neurobiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro kinase assay with site-specific mutagenesis and genetic rescue in cortical neurons, multiple orthogonal methods in one rigorous study","pmids":["27503845"],"is_preprint":false},{"year":2018,"finding":"MAP7D1 (and its paralog MAP7) bind to Disheveled, direct its cortical localization, and facilitate cortical targeting of microtubule plus-ends in response to Wnt5a signaling. Wnt5a signaling promotes MAP7D1 movement toward MT plus-ends, and this dynamics and Disheveled localization depend on kinesin-1 member KIF5B. Disheveled in turn stabilizes MAP7D1, forming a feedback loop.","method":"Co-immunoprecipitation; live-cell imaging; siRNA knockdown of MAP7, MAP7D1, and KIF5B; cortical localization assays in HeLa cells; Drosophila genetic analysis of Ensconsin (ortholog) and Disheveled","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP, live imaging, RNAi phenotypic analysis, and evolutionary validation in Drosophila across two organisms","pmids":["29880710"],"is_preprint":false},{"year":2022,"finding":"MAP7D1 stabilizes microtubules through a mechanism distinct from its paralog MAP7D2: MAP7D1 is required for maintenance of acetylated (stable) microtubules, whereas MAP7D2 stabilizes MTs via direct binding independent of acetylation. Both proteins show similar subcellular localization (centrosome and partially on MTs) and knockdown phenotypes in neuronal cells affecting cell motility and neurite outgrowth.","method":"siRNA knockdown; nocodazole resistance assay; immunofluorescence for acetylated/detyrosinated tubulin; neurite outgrowth and cell migration assays in mouse N1-E115 neuronal cells","journal":"Life science alliance","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — knockdown with specific phenotypic readouts and pharmacological dissection, single lab with two orthogonal approaches","pmids":["35470240"],"is_preprint":false},{"year":2023,"finding":"MAP7D1 interacts with DNA double-strand break repair proteins RAD50, BRCA1, and 53BP1. Downregulation of MAP7D1 causes strong G1 arrest and impairs DNA repair in G1-arrested cells, reducing RAD50 recruitment to chromatin and 53BP1 localization to damage sites, and increases p53 phosphorylation after γ-irradiation.","method":"Quantitative proteomics (interaction); siRNA knockdown; γ-irradiation; chromatin fractionation; immunofluorescence for 53BP1 foci; flow cytometry for cell cycle; western blot for p53 phosphorylation","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — proteomics-based interaction discovery with multiple functional readouts in a single lab study","pmids":["36852271"],"is_preprint":false},{"year":2021,"finding":"MAP7D1 (map7d1b in zebrafish) localizes to sarcomeres in cardiac and skeletal muscle. Disruption of map7d1b gene function exacerbates doxorubicin-induced cardiomyopathy, mechanistically conveyed by impaired autophagic degradation and elevated protein aggregation.","method":"Zebrafish genetic knockdown/knockout; doxorubicin treatment model; immunofluorescence for sarcomeric localization; autophagy flux assays; protein aggregation assays; expression validation in mice","journal":"BioMed research international","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — zebrafish loss-of-function with defined mechanistic readouts (autophagy, protein aggregation), validated in mice, single lab","pmids":["34327238"],"is_preprint":false},{"year":2025,"finding":"A MAP7D1 microtubule-binding domain mutation (R201W) disrupts MAP7D1 interaction with microtubules, causing reduced microtubule density, mitotic defects (multipolar/bipolar unstable spindles, lagging chromosomes, shortened inter-centrosomal distance), and RPS14 accumulation in incorrectly dividing cells. Overexpression of mutant MAP7D1 and MAP7D1 depletion in glioblastoma and HEK293T cells reproduce these phenotypes, confirming loss-of-function.","method":"Patient fibroblast analysis; overexpression of wild-type vs. mutant MAP7D1; siRNA knockdown; immunofluorescence for microtubule density and mitotic spindles; RPS14 localization","journal":"Disease models & mechanisms","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — domain-specific mutation with mechanistic cellular phenotypes validated in patient cells and two independent cell lines","pmids":["40856631"],"is_preprint":false},{"year":2025,"finding":"MAP7D1 selectively partitions onto detyrosinated microtubules (via expanded lattice states), creating specialized tracks for kinesin-1 (KIF5B). MAP7D1 density on microtubules increases during nutrient starvation and decreases upon nutrient stimulation, thereby controlling lysosome positioning: high MAP7D1 density localizes lysosomes perinuclearly (starvation), while reduced MAP7D1 density allows peripheral lysosome migration (nutrient repletion). Altered MAP7D1 levels impair lysosomal motility and nutrient signaling responsiveness.","method":"Live-cell imaging; MAP7D1 overexpression and knockdown; rigor kinesin co-localization assays; lysosome tracking; nutrient starvation/re-feeding experiments; projection-domain mutagenesis for MAP4 specificity","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal imaging and genetic methods in single lab preprint, not yet peer-reviewed","pmids":["bio_10.1101_2025.10.07.680844"],"is_preprint":true},{"year":2026,"finding":"MAP7D1 is a direct target of miR-423-5p, as confirmed by dual-luciferase reporter assay at the MAP7D1 3'UTR. Inhibition of MAP7D1 via miR-423-5p reduces tumor cell proliferation and increases apoptosis in esophageal cancer cells during radiotherapy.","method":"Dual-luciferase reporter assay; miR-423-5p mimic overexpression via engineered exosomes; CCK8 proliferation assay; flow cytometric apoptosis assay; xenograft mouse model","journal":"Annals of surgical oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — validated miRNA-target interaction by reporter assay with functional cellular and in vivo readouts, single lab","pmids":["42120691"],"is_preprint":false}],"current_model":"MAP7D1 is a microtubule-associated protein that binds preferentially to detyrosinated microtubules and stabilizes them (particularly acetylated stable MTs), serves as a kinesin-1 (KIF5B) track to regulate organelle (lysosome) positioning in response to nutrient signals, is phosphorylated by DCLK1 at Ser315 to promote neuronal axon elongation, binds Disheveled to facilitate Wnt5a/β-catenin-independent signaling, interacts with DNA double-strand break repair factors (RAD50, BRCA1, 53BP1) to support G1-phase repair, and is required for proper mitotic spindle function and cardiac/sarcomeric integrity."},"narrative":{"mechanistic_narrative":"MAP7D1 is a microtubule-associated protein that stabilizes specialized microtubule subpopulations and organizes kinesin-1-dependent transport along them [PMID:35470240, PMID:bio_10.1101_2025.10.07.680844]. It is required for maintenance of acetylated, stable microtubules through a mechanism distinct from its paralog MAP7D2, and a microtubule-binding-domain mutation (R201W) that abolishes microtubule association reduces microtubule density and produces mitotic defects including unstable spindles, lagging chromosomes, and shortened inter-centrosomal distance, establishing its role in spindle integrity [PMID:35470240, PMID:40856631]. MAP7D1 partitions selectively onto detyrosinated microtubules to create tracks for kinesin-1 (KIF5B), and its microtubule density is tuned by nutrient state to control lysosome positioning—high density during starvation drives perinuclear clustering, while reduced density permits peripheral lysosome migration [PMID:bio_10.1101_2025.10.07.680844]. In neurons, DCLK1 directly phosphorylates MAP7D1 at Ser315 to promote callosal axon elongation [PMID:27503845], and MAP7D1 binds Disheveled to direct its cortical localization and couple microtubule plus-end targeting to Wnt5a signaling in a KIF5B-dependent feedback loop [PMID:29880710]. Beyond cytoskeletal roles, MAP7D1 interacts with the DNA double-strand break repair factors RAD50, BRCA1, and 53BP1 and supports G1-phase repair by promoting RAD50 chromatin recruitment and 53BP1 focus formation [PMID:36852271], and it localizes to sarcomeres where its loss exacerbates doxorubicin-induced cardiomyopathy through impaired autophagic clearance and protein aggregation [PMID:34327238].","teleology":[{"year":2016,"claim":"Established MAP7D1 as a regulated effector in neuronal cytoskeletal remodeling by identifying it as a DCLK1 kinase substrate whose phosphorylation drives axon elongation.","evidence":"Proteomic substrate identification, in vitro kinase assay, phosphomimetic mutagenesis, and in utero electroporation rescue in cortical neurons","pmids":["27503845"],"confidence":"High","gaps":["Does not define how Ser315 phosphorylation alters MAP7D1 microtubule binding or kinesin recruitment","Limited to callosal axon elongation; broader neuronal contexts untested"]},{"year":2018,"claim":"Linked MAP7D1 to non-canonical Wnt signaling by showing it binds Disheveled and couples microtubule plus-end cortical targeting to Wnt5a via kinesin-1.","evidence":"Reciprocal Co-IP, live-cell imaging, siRNA knockdown of MAP7/MAP7D1/KIF5B in HeLa, and Drosophila Ensconsin/Disheveled genetics","pmids":["29880710"],"confidence":"High","gaps":["Direct vs. indirect nature of the Disheveled interaction not resolved structurally","Functional consequence of the MAP7D1–Disheveled feedback loop on downstream Wnt output not quantified"]},{"year":2021,"claim":"Identified a sarcomeric/cardioprotective role, showing map7d1b loss worsens doxorubicin cardiomyopathy via failed autophagic degradation and protein aggregation.","evidence":"Zebrafish loss-of-function with doxorubicin model, autophagy flux and aggregation assays, mouse expression validation","pmids":["34327238"],"confidence":"Medium","gaps":["Mechanism connecting sarcomeric MAP7D1 to autophagy is not molecularly defined","Human cardiac relevance untested"]},{"year":2022,"claim":"Defined MAP7D1's distinct microtubule-stabilizing mechanism—maintenance of acetylated stable microtubules—differentiating it from the acetylation-independent paralog MAP7D2.","evidence":"siRNA knockdown, nocodazole resistance, immunofluorescence for acetylated/detyrosinated tubulin, neurite outgrowth and migration assays in N1-E115 cells","pmids":["35470240"],"confidence":"Medium","gaps":["Molecular basis for preference toward acetylated microtubules not established","Single neuronal cell line"]},{"year":2023,"claim":"Expanded MAP7D1's role beyond the cytoskeleton by tying it to G1-phase DNA double-strand break repair through RAD50, BRCA1, and 53BP1.","evidence":"Quantitative interaction proteomics, siRNA knockdown, γ-irradiation, chromatin fractionation, 53BP1 foci imaging, cell-cycle flow cytometry, p53 phosphorylation western blot","pmids":["36852271"],"confidence":"Medium","gaps":["Whether MAP7D1 acts at damage sites directly or via cytoskeletal/cell-cycle effects is unresolved","Interactions discovered by proteomics lack reciprocal binding validation"]},{"year":2025,"claim":"Demonstrated MAP7D1 is required for mitotic spindle integrity by showing the microtubule-binding R201W mutation reproduces depletion phenotypes—unstable spindles, lagging chromosomes, and RPS14 mislocalization.","evidence":"Patient fibroblast analysis, wild-type vs. mutant overexpression, siRNA knockdown, spindle and microtubule density imaging in glioblastoma and HEK293T cells","pmids":["40856631"],"confidence":"Medium","gaps":["Disease genotype-phenotype link from a single patient mutation","Significance of RPS14 accumulation not mechanistically explained"]},{"year":2025,"claim":"Resolved how MAP7D1 enables selective transport, showing it partitions onto detyrosinated/expanded-lattice microtubules to build kinesin-1 tracks and tunes lysosome positioning to nutrient state.","evidence":"Live-cell imaging, overexpression/knockdown, kinesin co-localization, lysosome tracking, nutrient starvation/refeeding, projection-domain mutagenesis (preprint)","pmids":["bio_10.1101_2025.10.07.680844"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Signaling pathway sensing nutrients to alter MAP7D1 microtubule density not identified"]},{"year":2026,"claim":"Placed MAP7D1 in a cancer radioresponse axis as a direct miR-423-5p target whose suppression reduces proliferation and promotes apoptosis during radiotherapy.","evidence":"Dual-luciferase 3'UTR reporter, exosome-delivered miR-423-5p mimic, CCK8 proliferation, apoptosis flow cytometry, xenograft model in esophageal cancer","pmids":["42120691"],"confidence":"Medium","gaps":["Which MAP7D1 function (spindle, repair, transport) underlies the radioresponse phenotype is unknown","Single tumor type"]},{"year":null,"claim":"How MAP7D1's distinct activities—microtubule stabilization, kinesin-1 track formation, DSB repair, and sarcomeric maintenance—are coordinated or selected within a cell remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the microtubule-binding or projection domains","No unified mechanism linking cytoskeletal and DNA-repair functions"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[2,5,6]}],"localization":[{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[2,5,6]},{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[2]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[5]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[6]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[3]}],"complexes":[],"partners":["KIF5B","DVL","DCLK1","RAD50","BRCA1","TP53BP1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q3KQU3","full_name":"MAP7 domain-containing protein 1","aliases":["Arginine/proline-rich coiled-coil domain-containing protein 1","Proline/arginine-rich coiled-coil domain-containing protein 1"],"length_aa":841,"mass_kda":92.8,"function":"Microtubule-stabilizing protein involved in the control of cell motility and neurite outgrowth. Facilitate microtubule stabilization through the maintenance of acetylated stable microtubules","subcellular_location":"Cytoplasm, cytoskeleton, spindle; Cytoplasm, cytoskeleton; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome; Midbody","url":"https://www.uniprot.org/uniprotkb/Q3KQU3/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MAP7D1","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CKAP2","stoichiometry":0.2},{"gene":"MAP4","stoichiometry":0.2},{"gene":"PSPC1","stoichiometry":0.2},{"gene":"RACK1","stoichiometry":0.2},{"gene":"RPS16","stoichiometry":0.2},{"gene":"TUBB4B","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/MAP7D1","total_profiled":1310},"omim":[{"mim_id":"621363","title":"MAP7 DOMAIN-CONTAINING PROTEIN 1; MAP7D1","url":"https://www.omim.org/entry/621363"},{"mim_id":"604108","title":"MICROTUBULE-ASSOCIATED PROTEIN 7; MAP7","url":"https://www.omim.org/entry/604108"},{"mim_id":"301121","title":"MAP7 DOMAIN-CONTAINING PROTEIN 2; MAP7D2","url":"https://www.omim.org/entry/301121"},{"mim_id":"300930","title":"MAP7 DOMAIN-CONTAINING PROTEIN 3; MAP7D3","url":"https://www.omim.org/entry/300930"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"skeletal muscle","ntpm":267.9}],"url":"https://www.proteinatlas.org/search/MAP7D1"},"hgnc":{"alias_symbol":["FLJ10350","FLJ39022"],"prev_symbol":["PARCC1","RPRC1"]},"alphafold":{"accession":"Q3KQU3","domains":[{"cath_id":"-","chopping":"132-224","consensus_level":"high","plddt":88.8297,"start":132,"end":224},{"cath_id":"1.20.5","chopping":"619-694","consensus_level":"medium","plddt":88.5768,"start":619,"end":694}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q3KQU3","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q3KQU3-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q3KQU3-F1-predicted_aligned_error_v6.png","plddt_mean":58.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MAP7D1","jax_strain_url":"https://www.jax.org/strain/search?query=MAP7D1"},"sequence":{"accession":"Q3KQU3","fasta_url":"https://rest.uniprot.org/uniprotkb/Q3KQU3.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q3KQU3/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q3KQU3"}},"corpus_meta":[{"pmid":"10744690","id":"PMC_10744690","title":"The nuclear import of RCC1 requires a specific nuclear localization sequence receptor, karyopherin alpha3/Qip.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10744690","citation_count":56,"is_preprint":false},{"pmid":"27503845","id":"PMC_27503845","title":"DCLK1 phosphorylates the microtubule-associated protein MAP7D1 to promote axon elongation in cortical neurons.","date":"2016","source":"Developmental neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/27503845","citation_count":37,"is_preprint":false},{"pmid":"34863825","id":"PMC_34863825","title":"Emergence of unique SARS-CoV-2 ORF10 variants and their impact on protein structure and function.","date":"2021","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/34863825","citation_count":22,"is_preprint":false},{"pmid":"36895195","id":"PMC_36895195","title":"Repair mechanism of Yishen Tongluo formula on mouse sperm DNA fragmentation caused by polystyrene microplastics.","date":"2023","source":"Pharmaceutical biology","url":"https://pubmed.ncbi.nlm.nih.gov/36895195","citation_count":18,"is_preprint":false},{"pmid":"29880710","id":"PMC_29880710","title":"Map7/7D1 and Dvl form a feedback loop that facilitates microtubule remodeling and Wnt5a signaling.","date":"2018","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/29880710","citation_count":17,"is_preprint":false},{"pmid":"30808565","id":"PMC_30808565","title":"Characterization of whole blood transcriptome and early-life fecal microbiota in high and low responder pigs before, and after vaccination for Mycoplasma hyopneumoniae.","date":"2019","source":"Vaccine","url":"https://pubmed.ncbi.nlm.nih.gov/30808565","citation_count":16,"is_preprint":false},{"pmid":"33716151","id":"PMC_33716151","title":"Genome-wide 5-Hydroxymethylcytosine Profiling Analysis Identifies MAP7D1 as A Novel Regulator of Lymph Node Metastasis in Breast Cancer.","date":"2021","source":"Genomics, proteomics & bioinformatics","url":"https://pubmed.ncbi.nlm.nih.gov/33716151","citation_count":14,"is_preprint":false},{"pmid":"36852271","id":"PMC_36852271","title":"Microtubule-associated proteins MAP7 and MAP7D1 promote DNA double-strand break repair in the G1 cell cycle phase.","date":"2023","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/36852271","citation_count":10,"is_preprint":false},{"pmid":"35470240","id":"PMC_35470240","title":"Map7D2 and Map7D1 facilitate microtubule stabilization through distinct mechanisms in neuronal cells.","date":"2022","source":"Life science alliance","url":"https://pubmed.ncbi.nlm.nih.gov/35470240","citation_count":9,"is_preprint":false},{"pmid":"37250922","id":"PMC_37250922","title":"Identification of Rare Variants Involved in High Myopia Unraveled by Whole Genome Sequencing.","date":"2023","source":"Ophthalmology science","url":"https://pubmed.ncbi.nlm.nih.gov/37250922","citation_count":8,"is_preprint":false},{"pmid":"34327238","id":"PMC_34327238","title":"Disruption of MAP7D1 Gene Function Increases the Risk of Doxorubicin-Induced Cardiomyopathy and Heart Failure.","date":"2021","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/34327238","citation_count":6,"is_preprint":false},{"pmid":"40856631","id":"PMC_40856631","title":"A novel MAP7D1 mutation causes mitotic defects and RPS14 accumulation in Shwachman-Diamond syndrome patient cells.","date":"2025","source":"Disease models & mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/40856631","citation_count":0,"is_preprint":false},{"pmid":"42120691","id":"PMC_42120691","title":"Engineered Exosomes for Delivery of Mir-423-5p to Improve Radiation Sensitivity by Inhibiting MAP7D1 in Esophageal Cancer.","date":"2026","source":"Annals of surgical oncology","url":"https://pubmed.ncbi.nlm.nih.gov/42120691","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.10.07.680844","title":"MAP4-MAP7D1 partitioning on tyrosinated-detyrosinated microtubules coordinates lysosome positioning in nutrient signalling","date":"2025-10-07","source":"bioRxiv","url":"https://doi.org/10.1101/2025.10.07.680844","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9622,"output_tokens":2388,"usd":0.032343,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9522,"output_tokens":3164,"usd":0.063355,"stage2_stop_reason":"end_turn"},"total_usd":0.095698,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"DCLK1 directly phosphorylates MAP7D1 at serine 315 to promote axon elongation in cortical neurons. Knockdown of MAP7D1 impairs callosal axon elongation but not radial migration; overexpression of a phosphomimetic MAP7D1 S315E mutant rescues axon elongation defects in Dclk1 knockdown neurons, whereas wild-type MAP7D1 does not.\",\n      \"method\": \"Proteomic identification of DCLK1 substrate; in vitro phosphorylation assay; phosphomimetic/phosphodead mutagenesis; in utero electroporation knockdown with rescue experiments\",\n      \"journal\": \"Developmental neurobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro kinase assay with site-specific mutagenesis and genetic rescue in cortical neurons, multiple orthogonal methods in one rigorous study\",\n      \"pmids\": [\"27503845\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"MAP7D1 (and its paralog MAP7) bind to Disheveled, direct its cortical localization, and facilitate cortical targeting of microtubule plus-ends in response to Wnt5a signaling. Wnt5a signaling promotes MAP7D1 movement toward MT plus-ends, and this dynamics and Disheveled localization depend on kinesin-1 member KIF5B. Disheveled in turn stabilizes MAP7D1, forming a feedback loop.\",\n      \"method\": \"Co-immunoprecipitation; live-cell imaging; siRNA knockdown of MAP7, MAP7D1, and KIF5B; cortical localization assays in HeLa cells; Drosophila genetic analysis of Ensconsin (ortholog) and Disheveled\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP, live imaging, RNAi phenotypic analysis, and evolutionary validation in Drosophila across two organisms\",\n      \"pmids\": [\"29880710\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"MAP7D1 stabilizes microtubules through a mechanism distinct from its paralog MAP7D2: MAP7D1 is required for maintenance of acetylated (stable) microtubules, whereas MAP7D2 stabilizes MTs via direct binding independent of acetylation. Both proteins show similar subcellular localization (centrosome and partially on MTs) and knockdown phenotypes in neuronal cells affecting cell motility and neurite outgrowth.\",\n      \"method\": \"siRNA knockdown; nocodazole resistance assay; immunofluorescence for acetylated/detyrosinated tubulin; neurite outgrowth and cell migration assays in mouse N1-E115 neuronal cells\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — knockdown with specific phenotypic readouts and pharmacological dissection, single lab with two orthogonal approaches\",\n      \"pmids\": [\"35470240\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"MAP7D1 interacts with DNA double-strand break repair proteins RAD50, BRCA1, and 53BP1. Downregulation of MAP7D1 causes strong G1 arrest and impairs DNA repair in G1-arrested cells, reducing RAD50 recruitment to chromatin and 53BP1 localization to damage sites, and increases p53 phosphorylation after γ-irradiation.\",\n      \"method\": \"Quantitative proteomics (interaction); siRNA knockdown; γ-irradiation; chromatin fractionation; immunofluorescence for 53BP1 foci; flow cytometry for cell cycle; western blot for p53 phosphorylation\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — proteomics-based interaction discovery with multiple functional readouts in a single lab study\",\n      \"pmids\": [\"36852271\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MAP7D1 (map7d1b in zebrafish) localizes to sarcomeres in cardiac and skeletal muscle. Disruption of map7d1b gene function exacerbates doxorubicin-induced cardiomyopathy, mechanistically conveyed by impaired autophagic degradation and elevated protein aggregation.\",\n      \"method\": \"Zebrafish genetic knockdown/knockout; doxorubicin treatment model; immunofluorescence for sarcomeric localization; autophagy flux assays; protein aggregation assays; expression validation in mice\",\n      \"journal\": \"BioMed research international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — zebrafish loss-of-function with defined mechanistic readouts (autophagy, protein aggregation), validated in mice, single lab\",\n      \"pmids\": [\"34327238\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A MAP7D1 microtubule-binding domain mutation (R201W) disrupts MAP7D1 interaction with microtubules, causing reduced microtubule density, mitotic defects (multipolar/bipolar unstable spindles, lagging chromosomes, shortened inter-centrosomal distance), and RPS14 accumulation in incorrectly dividing cells. Overexpression of mutant MAP7D1 and MAP7D1 depletion in glioblastoma and HEK293T cells reproduce these phenotypes, confirming loss-of-function.\",\n      \"method\": \"Patient fibroblast analysis; overexpression of wild-type vs. mutant MAP7D1; siRNA knockdown; immunofluorescence for microtubule density and mitotic spindles; RPS14 localization\",\n      \"journal\": \"Disease models & mechanisms\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain-specific mutation with mechanistic cellular phenotypes validated in patient cells and two independent cell lines\",\n      \"pmids\": [\"40856631\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MAP7D1 selectively partitions onto detyrosinated microtubules (via expanded lattice states), creating specialized tracks for kinesin-1 (KIF5B). MAP7D1 density on microtubules increases during nutrient starvation and decreases upon nutrient stimulation, thereby controlling lysosome positioning: high MAP7D1 density localizes lysosomes perinuclearly (starvation), while reduced MAP7D1 density allows peripheral lysosome migration (nutrient repletion). Altered MAP7D1 levels impair lysosomal motility and nutrient signaling responsiveness.\",\n      \"method\": \"Live-cell imaging; MAP7D1 overexpression and knockdown; rigor kinesin co-localization assays; lysosome tracking; nutrient starvation/re-feeding experiments; projection-domain mutagenesis for MAP4 specificity\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal imaging and genetic methods in single lab preprint, not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.10.07.680844\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"MAP7D1 is a direct target of miR-423-5p, as confirmed by dual-luciferase reporter assay at the MAP7D1 3'UTR. Inhibition of MAP7D1 via miR-423-5p reduces tumor cell proliferation and increases apoptosis in esophageal cancer cells during radiotherapy.\",\n      \"method\": \"Dual-luciferase reporter assay; miR-423-5p mimic overexpression via engineered exosomes; CCK8 proliferation assay; flow cytometric apoptosis assay; xenograft mouse model\",\n      \"journal\": \"Annals of surgical oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — validated miRNA-target interaction by reporter assay with functional cellular and in vivo readouts, single lab\",\n      \"pmids\": [\"42120691\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MAP7D1 is a microtubule-associated protein that binds preferentially to detyrosinated microtubules and stabilizes them (particularly acetylated stable MTs), serves as a kinesin-1 (KIF5B) track to regulate organelle (lysosome) positioning in response to nutrient signals, is phosphorylated by DCLK1 at Ser315 to promote neuronal axon elongation, binds Disheveled to facilitate Wnt5a/β-catenin-independent signaling, interacts with DNA double-strand break repair factors (RAD50, BRCA1, 53BP1) to support G1-phase repair, and is required for proper mitotic spindle function and cardiac/sarcomeric integrity.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"MAP7D1 is a microtubule-associated protein that stabilizes specialized microtubule subpopulations and organizes kinesin-1-dependent transport along them [#2, #6]. It is required for maintenance of acetylated, stable microtubules through a mechanism distinct from its paralog MAP7D2, and a microtubule-binding-domain mutation (R201W) that abolishes microtubule association reduces microtubule density and produces mitotic defects including unstable spindles, lagging chromosomes, and shortened inter-centrosomal distance, establishing its role in spindle integrity [#2, #5]. MAP7D1 partitions selectively onto detyrosinated microtubules to create tracks for kinesin-1 (KIF5B), and its microtubule density is tuned by nutrient state to control lysosome positioning—high density during starvation drives perinuclear clustering, while reduced density permits peripheral lysosome migration [#6]. In neurons, DCLK1 directly phosphorylates MAP7D1 at Ser315 to promote callosal axon elongation [#0], and MAP7D1 binds Disheveled to direct its cortical localization and couple microtubule plus-end targeting to Wnt5a signaling in a KIF5B-dependent feedback loop [#1]. Beyond cytoskeletal roles, MAP7D1 interacts with the DNA double-strand break repair factors RAD50, BRCA1, and 53BP1 and supports G1-phase repair by promoting RAD50 chromatin recruitment and 53BP1 focus formation [#3], and it localizes to sarcomeres where its loss exacerbates doxorubicin-induced cardiomyopathy through impaired autophagic clearance and protein aggregation [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 2016,\n      \"claim\": \"Established MAP7D1 as a regulated effector in neuronal cytoskeletal remodeling by identifying it as a DCLK1 kinase substrate whose phosphorylation drives axon elongation.\",\n      \"evidence\": \"Proteomic substrate identification, in vitro kinase assay, phosphomimetic mutagenesis, and in utero electroporation rescue in cortical neurons\",\n      \"pmids\": [\"27503845\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not define how Ser315 phosphorylation alters MAP7D1 microtubule binding or kinesin recruitment\", \"Limited to callosal axon elongation; broader neuronal contexts untested\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Linked MAP7D1 to non-canonical Wnt signaling by showing it binds Disheveled and couples microtubule plus-end cortical targeting to Wnt5a via kinesin-1.\",\n      \"evidence\": \"Reciprocal Co-IP, live-cell imaging, siRNA knockdown of MAP7/MAP7D1/KIF5B in HeLa, and Drosophila Ensconsin/Disheveled genetics\",\n      \"pmids\": [\"29880710\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct vs. indirect nature of the Disheveled interaction not resolved structurally\", \"Functional consequence of the MAP7D1–Disheveled feedback loop on downstream Wnt output not quantified\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified a sarcomeric/cardioprotective role, showing map7d1b loss worsens doxorubicin cardiomyopathy via failed autophagic degradation and protein aggregation.\",\n      \"evidence\": \"Zebrafish loss-of-function with doxorubicin model, autophagy flux and aggregation assays, mouse expression validation\",\n      \"pmids\": [\"34327238\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting sarcomeric MAP7D1 to autophagy is not molecularly defined\", \"Human cardiac relevance untested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined MAP7D1's distinct microtubule-stabilizing mechanism—maintenance of acetylated stable microtubules—differentiating it from the acetylation-independent paralog MAP7D2.\",\n      \"evidence\": \"siRNA knockdown, nocodazole resistance, immunofluorescence for acetylated/detyrosinated tubulin, neurite outgrowth and migration assays in N1-E115 cells\",\n      \"pmids\": [\"35470240\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis for preference toward acetylated microtubules not established\", \"Single neuronal cell line\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Expanded MAP7D1's role beyond the cytoskeleton by tying it to G1-phase DNA double-strand break repair through RAD50, BRCA1, and 53BP1.\",\n      \"evidence\": \"Quantitative interaction proteomics, siRNA knockdown, γ-irradiation, chromatin fractionation, 53BP1 foci imaging, cell-cycle flow cytometry, p53 phosphorylation western blot\",\n      \"pmids\": [\"36852271\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether MAP7D1 acts at damage sites directly or via cytoskeletal/cell-cycle effects is unresolved\", \"Interactions discovered by proteomics lack reciprocal binding validation\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated MAP7D1 is required for mitotic spindle integrity by showing the microtubule-binding R201W mutation reproduces depletion phenotypes—unstable spindles, lagging chromosomes, and RPS14 mislocalization.\",\n      \"evidence\": \"Patient fibroblast analysis, wild-type vs. mutant overexpression, siRNA knockdown, spindle and microtubule density imaging in glioblastoma and HEK293T cells\",\n      \"pmids\": [\"40856631\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Disease genotype-phenotype link from a single patient mutation\", \"Significance of RPS14 accumulation not mechanistically explained\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved how MAP7D1 enables selective transport, showing it partitions onto detyrosinated/expanded-lattice microtubules to build kinesin-1 tracks and tunes lysosome positioning to nutrient state.\",\n      \"evidence\": \"Live-cell imaging, overexpression/knockdown, kinesin co-localization, lysosome tracking, nutrient starvation/refeeding, projection-domain mutagenesis (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.10.07.680844\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Signaling pathway sensing nutrients to alter MAP7D1 microtubule density not identified\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Placed MAP7D1 in a cancer radioresponse axis as a direct miR-423-5p target whose suppression reduces proliferation and promotes apoptosis during radiotherapy.\",\n      \"evidence\": \"Dual-luciferase 3'UTR reporter, exosome-delivered miR-423-5p mimic, CCK8 proliferation, apoptosis flow cytometry, xenograft model in esophageal cancer\",\n      \"pmids\": [\"42120691\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Which MAP7D1 function (spindle, repair, transport) underlies the radioresponse phenotype is unknown\", \"Single tumor type\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How MAP7D1's distinct activities—microtubule stabilization, kinesin-1 track formation, DSB repair, and sarcomeric maintenance—are coordinated or selected within a cell remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the microtubule-binding or projection domains\", \"No unified mechanism linking cytoskeletal and DNA-repair functions\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [2, 5, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [2, 5, 6]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [6]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"KIF5B\", \"DVL\", \"DCLK1\", \"RAD50\", \"BRCA1\", \"TP53BP1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}