{"gene":"DOP1B","run_date":"2026-06-09T23:54:42","timeline":{"discoveries":[{"year":2000,"finding":"C21orf5 (DOP1B) ortholog in C. elegans (pad-1) is required for embryonic patterning: RNAi knockdown causes embryonic lethality with failure of tissue patterning during gastrulation and absence of morphogenesis, establishing an essential role in developmental patterning.","method":"Double-stranded RNA-mediated genetic interference (RNAi) in C. elegans; Northern blot; RNA in situ hybridization","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean loss-of-function with specific phenotypic readout in C. elegans ortholog; single lab but orthogonal methods (RNAi + expression analysis)","pmids":["10950924"],"is_preprint":false},{"year":2005,"finding":"C21orf5 (DOP1B) protein contains two highly conserved leucine-zipper-like domains at its C-terminus, placing it as a new member of the Dopey leucine zipper-like family (alongside Aspergillus nidulans DopA, S. cerevisiae Dop1, and C. elegans pad-1), with a conserved function in morphogenesis across phylogenesis.","method":"Comparative protein sequence analysis across species; transgenic mouse overexpression with in situ hybridization and real-time RT-PCR; cortical cell density measurement","journal":"DNA research","confidence":"Low","confidence_rationale":"Tier 4 / Weak — domain assignment is computational; in vivo overexpression shows cortical cell density increase but no direct mechanistic follow-up on the leucine-zipper domains","pmids":["16303751"],"is_preprint":false},{"year":2018,"finding":"DOPEY2 forms an evolutionarily conserved endosome-associated complex with MON2 and the putative aminophospholipid translocase ATP9A; this complex is required for SNX3-retromer-mediated endosome-to-Golgi transport of Wntless, and in vivo suppression of C. elegans orthologs (Ce-mon-2, Ce-pad-1/DOPEY2, Ce-tat-5/ATP9A) phenocopies SNX3-retromer loss, causing enhanced lysosomal degradation of Wntless and a Wnt signaling phenotype.","method":"Co-immunoprecipitation; in vivo C. elegans RNAi suppression; ATPase-inhibited TAT-5(E246Q) mutant overexpression; biochemical fractionation; cell biology assays for Wntless trafficking","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP establishing trimeric complex, in vivo genetic epistasis in C. elegans, dominant-negative mutant experiment, replicated across in vitro and in vivo systems","pmids":["30213940"],"is_preprint":false},{"year":2020,"finding":"Membrane-bound DOPEY2 is recruited to recycling endosomes (RE) dependent upon MON2 expression; DOPEY2 shows binding to kinesin and dynein/dynactin motor proteins; DOPEY2 knockout causes accumulation of RE at perinuclear regions rather than the peripheral distribution seen in wild-type cells, establishing DOPEY2 as a regulator of RE positioning/distribution downstream of MON2.","method":"Live imaging; biochemical co-immunoprecipitation (binding to motor proteins); DOPEY2 knockout cell lines; MON2 knockout cell lines; subcellular co-localization with RAB4B (RE marker) and SNX3 (EE marker)","journal":"Cell structure and function","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct localization experiment with functional consequence (KO + defined organelle phenotype), motor protein binding by pulldown, live imaging, multiple orthogonal approaches in single study","pmids":["32404555"],"is_preprint":false},{"year":2023,"finding":"Dopey2 is responsible for the proliferation of neural stem cells/progenitors during embryonic neurogenesis in zebrafish; Dopey2 and Pcdh7 mutually restrict each other's expression, and loss of Dopey2 disrupts proper brain size and architecture.","method":"Zebrafish genetic mutants; proliferation assays of neural stem cells/progenitors; expression analysis of Dopey2 and Pcdh7 in mutant backgrounds","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — clean loss-of-function in zebrafish with specific neural proliferation phenotype and mutual expression epistasis, but single lab and limited mechanistic detail in abstract","pmids":["36936789"],"is_preprint":false},{"year":2020,"finding":"A homozygous variant in DOP1B (p.Val1660 in a conserved residue) segregates with autosomal recessive Peters anomaly in a consanguineous family; DOP1B is expressed in lens, iris, cornea, sclera, and retina of human embryonic and adult eye tissues.","method":"Exome sequencing with variant segregation analysis; real-time PCR expression analysis in human ocular tissues","journal":"Molecular vision","confidence":"Low","confidence_rationale":"Tier 3 / Weak — variant segregation establishes genetic association and expression data localizes gene to relevant tissues, but no functional experiment confirms the mechanism; single family","pmids":["33273802"],"is_preprint":false}],"current_model":"DOP1B (DOPEY2/C21orf5) encodes a large leucine-zipper-like protein that forms an evolutionarily conserved trimeric complex with MON2 and the aminophospholipid translocase ATP9A on recycling endosomes; this complex promotes SNX3-retromer-mediated endosome-to-Golgi retrograde transport (established for Wntless/Wnt secretion), with DOPEY2 recruited to recycling endosomes in a MON2-dependent manner and binding kinesin and dynein/dynactin motors to regulate endosomal positioning, while its C. elegans ortholog (pad-1) is additionally required for embryonic tissue patterning and its zebrafish ortholog regulates neural stem cell proliferation during brain development."},"narrative":{"mechanistic_narrative":"DOP1B (DOPEY2/C21orf5) is a large leucine-zipper-like protein that controls endosomal retrograde trafficking and organelle positioning, with a deeply conserved role in tissue morphogenesis [PMID:10950924, PMID:30213940]. It assembles into an evolutionarily conserved endosome-associated complex with MON2 and the putative aminophospholipid translocase ATP9A, and this complex is required for SNX3-retromer-mediated endosome-to-Golgi transport of Wntless; loss of the complex shunts Wntless to lysosomal degradation and disrupts Wnt signaling [PMID:30213940]. DOPEY2 is recruited to recycling endosomes in a MON2-dependent manner and binds both kinesin and dynein/dynactin motors, so that its loss causes recycling endosomes to accumulate perinuclearly instead of distributing peripherally — placing DOPEY2 as a motor-coupled regulator of endosome positioning downstream of MON2 [PMID:32404555]. Across organisms this trafficking function underlies developmental roles: the C. elegans ortholog pad-1 is essential for embryonic tissue patterning during gastrulation [PMID:10950924], and the zebrafish ortholog drives neural stem/progenitor proliferation, mutually restricting Pcdh7 expression to set brain size and architecture [PMID:36936789]. A homozygous DOP1B variant segregates with autosomal recessive Peters anomaly in a consanguineous family, linking the gene to ocular developmental disease [PMID:33273802].","teleology":[{"year":2000,"claim":"Established that the DOP1B ortholog is essential for development by showing its loss blocks embryonic tissue patterning, before any molecular function was known.","evidence":"RNAi knockdown of pad-1 in C. elegans with expression analysis","pmids":["10950924"],"confidence":"Medium","gaps":["No molecular mechanism connecting the gene to patterning identified","Phenotype shown only in worm ortholog"]},{"year":2005,"claim":"Defined DOP1B as a member of the Dopey leucine-zipper-like family with conserved C-terminal domains, framing a conserved morphogenesis function across phylogeny.","evidence":"Comparative sequence analysis and transgenic mouse overexpression with cortical cell density measurement","pmids":["16303751"],"confidence":"Low","gaps":["Leucine-zipper domain function not tested directly","Overexpression phenotype not mechanistically linked to trafficking"]},{"year":2018,"claim":"Resolved the molecular activity by showing DOPEY2 forms a trimeric complex with MON2 and ATP9A required for SNX3-retromer endosome-to-Golgi transport of Wntless, connecting the gene to Wnt signaling.","evidence":"Reciprocal Co-IP, in vivo C. elegans RNAi epistasis, and dominant-negative TAT-5(E246Q) overexpression","pmids":["30213940"],"confidence":"High","gaps":["Stoichiometry and structural basis of the complex unresolved","Direct cargo set beyond Wntless not defined","Catalytic contribution of ATP9A translocase activity to DOPEY2 function unclear"]},{"year":2020,"claim":"Showed how DOPEY2 acts mechanically: it is recruited to recycling endosomes via MON2 and binds kinesin and dynein/dynactin motors to control endosome positioning.","evidence":"Live imaging, motor-protein Co-IP, and DOPEY2/MON2 knockout cell lines with organelle distribution readout","pmids":["32404555"],"confidence":"High","gaps":["How DOPEY2 switches between opposing motors not defined","Link between positioning defect and retrograde cargo transport not directly tested"]},{"year":2023,"claim":"Extended the developmental role to vertebrate neurogenesis, showing Dopey2 drives neural stem/progenitor proliferation and reciprocally restricts Pcdh7 to shape brain size.","evidence":"Zebrafish genetic mutants with neural progenitor proliferation and expression epistasis assays","pmids":["36936789"],"confidence":"Medium","gaps":["Mechanism linking endosomal trafficking to proliferation not established","Nature of Dopey2-Pcdh7 mutual restriction unknown"]},{"year":2020,"claim":"Linked DOP1B to human disease by identifying a homozygous variant segregating with autosomal recessive Peters anomaly and localizing expression to ocular tissues.","evidence":"Exome sequencing with segregation analysis and RT-PCR in human eye tissues","pmids":["33273802"],"confidence":"Low","gaps":["No functional validation of the variant","Single consanguineous family","Trafficking mechanism linking gene to ocular phenotype untested"]},{"year":null,"claim":"How DOPEY2's endosomal trafficking and motor-coupling functions mechanistically produce its developmental and disease phenotypes remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the DOPEY2-MON2-ATP9A complex","Cargo repertoire beyond Wntless undefined","Mechanistic bridge from trafficking to neural proliferation and ocular development missing"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[3]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,3]}],"localization":[{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[2,3]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[2,3]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[2]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,4]}],"complexes":["DOPEY2-MON2-ATP9A complex"],"partners":["MON2","ATP9A"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9Y3R5","full_name":"Protein DOP1B","aliases":[],"length_aa":2298,"mass_kda":258.2,"function":"May play a role in regulating membrane trafficking of cargo proteins. Together with ATP9A and MON2, regulates SNX3 retromer-mediated endosomal sorting of WLS away from lysosomal degradation","subcellular_location":"Early endosome membrane; Golgi apparatus membrane","url":"https://www.uniprot.org/uniprotkb/Q9Y3R5/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/DOP1B","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/DOP1B","total_profiled":1310},"omim":[{"mim_id":"604803","title":"DOP1 LEUCINE ZIPPER-LIKE PROTEIN B; DOP1B","url":"https://www.omim.org/entry/604803"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Mitochondria","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"parathyroid gland","ntpm":24.1}],"url":"https://www.proteinatlas.org/search/DOP1B"},"hgnc":{"alias_symbol":["KIAA0933"],"prev_symbol":["C21orf5","DOPEY2"]},"alphafold":{"accession":"Q9Y3R5","domains":[{"cath_id":"-","chopping":"364-539","consensus_level":"medium","plddt":81.5174,"start":364,"end":539},{"cath_id":"-","chopping":"871-990","consensus_level":"medium","plddt":84.8342,"start":871,"end":990},{"cath_id":"-","chopping":"1004-1020_1224-1405_1422-1460_1481-1530","consensus_level":"medium","plddt":81.5675,"start":1004,"end":1530},{"cath_id":"-","chopping":"1780-1867_1893-1964","consensus_level":"medium","plddt":85.2664,"start":1780,"end":1964},{"cath_id":"-","chopping":"2016-2113_2143-2183_2200-2218_2225-2257_2270-2293","consensus_level":"medium","plddt":77.6994,"start":2016,"end":2293},{"cath_id":"1.25.40","chopping":"178-300","consensus_level":"medium","plddt":88.5376,"start":178,"end":300}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y3R5","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y3R5-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y3R5-F1-predicted_aligned_error_v6.png","plddt_mean":71.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=DOP1B","jax_strain_url":"https://www.jax.org/strain/search?query=DOP1B"},"sequence":{"accession":"Q9Y3R5","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y3R5.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y3R5/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y3R5"}},"corpus_meta":[{"pmid":"30213940","id":"PMC_30213940","title":"SNX3-retromer requires an evolutionary conserved MON2:DOPEY2:ATP9A complex to mediate Wntless sorting and Wnt secretion.","date":"2018","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/30213940","citation_count":71,"is_preprint":false},{"pmid":"22486522","id":"PMC_22486522","title":"Analysis of copy number variation in Alzheimer's disease: the NIALOAD/ NCRAD Family Study.","date":"2012","source":"Current Alzheimer research","url":"https://pubmed.ncbi.nlm.nih.gov/22486522","citation_count":61,"is_preprint":false},{"pmid":"34781999","id":"PMC_34781999","title":"CircRNA-DOPEY2 enhances the chemosensitivity of esophageal cancer cells by inhibiting CPEB4-mediated Mcl-1 translation.","date":"2021","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/34781999","citation_count":52,"is_preprint":false},{"pmid":"25052193","id":"PMC_25052193","title":"Functional transcriptome analysis of the postnatal brain of the Ts1Cje mouse model for Down syndrome reveals global disruption of interferon-related molecular networks.","date":"2014","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/25052193","citation_count":51,"is_preprint":false},{"pmid":"23227193","id":"PMC_23227193","title":"Analysis of copy number variation in Alzheimer's disease in a cohort of clinically characterized and neuropathologically verified individuals.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23227193","citation_count":45,"is_preprint":false},{"pmid":"10950924","id":"PMC_10950924","title":"C21orf5, a novel human chromosome 21 gene, has a Caenorhabditis elegans ortholog (pad-1) required for embryonic patterning.","date":"2000","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/10950924","citation_count":19,"is_preprint":false},{"pmid":"16303751","id":"PMC_16303751","title":"C21orf5, a new member of Dopey family involved in morphogenesis, could participate in neurological alterations and mental retardation in Down syndrome.","date":"2005","source":"DNA research : an international journal for rapid publication of reports on genes and genomes","url":"https://pubmed.ncbi.nlm.nih.gov/16303751","citation_count":18,"is_preprint":false},{"pmid":"12767918","id":"PMC_12767918","title":"The differentially expressed C21orf5 gene in the medial temporal-lobe system could play a role in mental retardation in Down syndrome and transgenic mice.","date":"2003","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/12767918","citation_count":15,"is_preprint":false},{"pmid":"32404555","id":"PMC_32404555","title":"MON2 Guides Wntless Transport to the Golgi through Recycling Endosomes.","date":"2020","source":"Cell structure and function","url":"https://pubmed.ncbi.nlm.nih.gov/32404555","citation_count":14,"is_preprint":false},{"pmid":"16276086","id":"PMC_16276086","title":"C21orf5, a human candidate gene for brain abnormalities and mental retardation in Down syndrome.","date":"2006","source":"Cytogenetic and genome research","url":"https://pubmed.ncbi.nlm.nih.gov/16276086","citation_count":13,"is_preprint":false},{"pmid":"29197136","id":"PMC_29197136","title":"Properties of human genes guided by their enrichment in rare and common variants.","date":"2017","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/29197136","citation_count":12,"is_preprint":false},{"pmid":"33358789","id":"PMC_33358789","title":"Comparative accuracies of genetic values predicted for economically important milk traits, genome-wide association, and linkage disequilibrium patterns of Canadian Holstein cows.","date":"2020","source":"Journal of dairy science","url":"https://pubmed.ncbi.nlm.nih.gov/33358789","citation_count":12,"is_preprint":false},{"pmid":"36430375","id":"PMC_36430375","title":"Indirect Immobilised Jagged-1 Enhances Matrisome Proteins Associated with Osteogenic Differentiation of Human Dental Pulp Stem Cells: A Proteomic Study.","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36430375","citation_count":9,"is_preprint":false},{"pmid":"17963726","id":"PMC_17963726","title":"New cerebellar phenotypes in YAC transgenic mouse in vivo library of human Down syndrome critical region-1.","date":"2007","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/17963726","citation_count":9,"is_preprint":false},{"pmid":"33273802","id":"PMC_33273802","title":"A mutation in DOP1B identified as a probable cause for autosomal recessive Peters anomaly in a consanguineous family.","date":"2020","source":"Molecular vision","url":"https://pubmed.ncbi.nlm.nih.gov/33273802","citation_count":5,"is_preprint":false},{"pmid":"32566271","id":"PMC_32566271","title":"Autoimmune Mechanisms of Interferon Hypersensitivity and Neurodegenerative Diseases: Down Syndrome.","date":"2020","source":"Autoimmune diseases","url":"https://pubmed.ncbi.nlm.nih.gov/32566271","citation_count":5,"is_preprint":false},{"pmid":"36936789","id":"PMC_36936789","title":"Dopey2 and Pcdh7 orchestrate the development of embryonic neural stem cells/ progenitors in zebrafish.","date":"2023","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/36936789","citation_count":3,"is_preprint":false},{"pmid":"39001529","id":"PMC_39001529","title":"Real-World Clinical Utility of Targeted RNA Sequencing in Leukemia Diagnosis and Management.","date":"2024","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/39001529","citation_count":3,"is_preprint":false},{"pmid":"38978356","id":"PMC_38978356","title":"Revisiting the impact of genomic hot spots: C12orf35 locus as a hot spot and engineering target.","date":"2024","source":"Biotechnology and bioengineering","url":"https://pubmed.ncbi.nlm.nih.gov/38978356","citation_count":2,"is_preprint":false},{"pmid":"39238827","id":"PMC_39238827","title":"A genetic investigation in five Chinese families with keratoconus.","date":"2024","source":"PeerJ","url":"https://pubmed.ncbi.nlm.nih.gov/39238827","citation_count":0,"is_preprint":false},{"pmid":"16378112","id":"PMC_16378112","title":"[Cell-cycle negative regulatory gene ANA is over-expressed in the brain tissues of patients with Down syndrome].","date":"2005","source":"Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences","url":"https://pubmed.ncbi.nlm.nih.gov/16378112","citation_count":0,"is_preprint":false},{"pmid":"42220229","id":"PMC_42220229","title":"Real-world-data for phenotypes and genotypes of rare monogenic genetic epilepsies and genes of uncertain significance for epilepsy.","date":"2026","source":"Epilepsia open","url":"https://pubmed.ncbi.nlm.nih.gov/42220229","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13992,"output_tokens":1735,"usd":0.034001,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8566,"output_tokens":2415,"usd":0.051603,"stage2_stop_reason":"end_turn"},"total_usd":0.085604,"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\": 2000,\n      \"finding\": \"C21orf5 (DOP1B) ortholog in C. elegans (pad-1) is required for embryonic patterning: RNAi knockdown causes embryonic lethality with failure of tissue patterning during gastrulation and absence of morphogenesis, establishing an essential role in developmental patterning.\",\n      \"method\": \"Double-stranded RNA-mediated genetic interference (RNAi) in C. elegans; Northern blot; RNA in situ hybridization\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean loss-of-function with specific phenotypic readout in C. elegans ortholog; single lab but orthogonal methods (RNAi + expression analysis)\",\n      \"pmids\": [\"10950924\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"C21orf5 (DOP1B) protein contains two highly conserved leucine-zipper-like domains at its C-terminus, placing it as a new member of the Dopey leucine zipper-like family (alongside Aspergillus nidulans DopA, S. cerevisiae Dop1, and C. elegans pad-1), with a conserved function in morphogenesis across phylogenesis.\",\n      \"method\": \"Comparative protein sequence analysis across species; transgenic mouse overexpression with in situ hybridization and real-time RT-PCR; cortical cell density measurement\",\n      \"journal\": \"DNA research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — domain assignment is computational; in vivo overexpression shows cortical cell density increase but no direct mechanistic follow-up on the leucine-zipper domains\",\n      \"pmids\": [\"16303751\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"DOPEY2 forms an evolutionarily conserved endosome-associated complex with MON2 and the putative aminophospholipid translocase ATP9A; this complex is required for SNX3-retromer-mediated endosome-to-Golgi transport of Wntless, and in vivo suppression of C. elegans orthologs (Ce-mon-2, Ce-pad-1/DOPEY2, Ce-tat-5/ATP9A) phenocopies SNX3-retromer loss, causing enhanced lysosomal degradation of Wntless and a Wnt signaling phenotype.\",\n      \"method\": \"Co-immunoprecipitation; in vivo C. elegans RNAi suppression; ATPase-inhibited TAT-5(E246Q) mutant overexpression; biochemical fractionation; cell biology assays for Wntless trafficking\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP establishing trimeric complex, in vivo genetic epistasis in C. elegans, dominant-negative mutant experiment, replicated across in vitro and in vivo systems\",\n      \"pmids\": [\"30213940\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Membrane-bound DOPEY2 is recruited to recycling endosomes (RE) dependent upon MON2 expression; DOPEY2 shows binding to kinesin and dynein/dynactin motor proteins; DOPEY2 knockout causes accumulation of RE at perinuclear regions rather than the peripheral distribution seen in wild-type cells, establishing DOPEY2 as a regulator of RE positioning/distribution downstream of MON2.\",\n      \"method\": \"Live imaging; biochemical co-immunoprecipitation (binding to motor proteins); DOPEY2 knockout cell lines; MON2 knockout cell lines; subcellular co-localization with RAB4B (RE marker) and SNX3 (EE marker)\",\n      \"journal\": \"Cell structure and function\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiment with functional consequence (KO + defined organelle phenotype), motor protein binding by pulldown, live imaging, multiple orthogonal approaches in single study\",\n      \"pmids\": [\"32404555\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Dopey2 is responsible for the proliferation of neural stem cells/progenitors during embryonic neurogenesis in zebrafish; Dopey2 and Pcdh7 mutually restrict each other's expression, and loss of Dopey2 disrupts proper brain size and architecture.\",\n      \"method\": \"Zebrafish genetic mutants; proliferation assays of neural stem cells/progenitors; expression analysis of Dopey2 and Pcdh7 in mutant backgrounds\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — clean loss-of-function in zebrafish with specific neural proliferation phenotype and mutual expression epistasis, but single lab and limited mechanistic detail in abstract\",\n      \"pmids\": [\"36936789\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"A homozygous variant in DOP1B (p.Val1660 in a conserved residue) segregates with autosomal recessive Peters anomaly in a consanguineous family; DOP1B is expressed in lens, iris, cornea, sclera, and retina of human embryonic and adult eye tissues.\",\n      \"method\": \"Exome sequencing with variant segregation analysis; real-time PCR expression analysis in human ocular tissues\",\n      \"journal\": \"Molecular vision\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — variant segregation establishes genetic association and expression data localizes gene to relevant tissues, but no functional experiment confirms the mechanism; single family\",\n      \"pmids\": [\"33273802\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"DOP1B (DOPEY2/C21orf5) encodes a large leucine-zipper-like protein that forms an evolutionarily conserved trimeric complex with MON2 and the aminophospholipid translocase ATP9A on recycling endosomes; this complex promotes SNX3-retromer-mediated endosome-to-Golgi retrograde transport (established for Wntless/Wnt secretion), with DOPEY2 recruited to recycling endosomes in a MON2-dependent manner and binding kinesin and dynein/dynactin motors to regulate endosomal positioning, while its C. elegans ortholog (pad-1) is additionally required for embryonic tissue patterning and its zebrafish ortholog regulates neural stem cell proliferation during brain development.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"DOP1B (DOPEY2/C21orf5) is a large leucine-zipper-like protein that controls endosomal retrograde trafficking and organelle positioning, with a deeply conserved role in tissue morphogenesis [#0, #2]. It assembles into an evolutionarily conserved endosome-associated complex with MON2 and the putative aminophospholipid translocase ATP9A, and this complex is required for SNX3-retromer-mediated endosome-to-Golgi transport of Wntless; loss of the complex shunts Wntless to lysosomal degradation and disrupts Wnt signaling [#2]. DOPEY2 is recruited to recycling endosomes in a MON2-dependent manner and binds both kinesin and dynein/dynactin motors, so that its loss causes recycling endosomes to accumulate perinuclearly instead of distributing peripherally — placing DOPEY2 as a motor-coupled regulator of endosome positioning downstream of MON2 [#3]. Across organisms this trafficking function underlies developmental roles: the C. elegans ortholog pad-1 is essential for embryonic tissue patterning during gastrulation [#0], and the zebrafish ortholog drives neural stem/progenitor proliferation, mutually restricting Pcdh7 expression to set brain size and architecture [#4]. A homozygous DOP1B variant segregates with autosomal recessive Peters anomaly in a consanguineous family, linking the gene to ocular developmental disease [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established that the DOP1B ortholog is essential for development by showing its loss blocks embryonic tissue patterning, before any molecular function was known.\",\n      \"evidence\": \"RNAi knockdown of pad-1 in C. elegans with expression analysis\",\n      \"pmids\": [\"10950924\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No molecular mechanism connecting the gene to patterning identified\", \"Phenotype shown only in worm ortholog\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Defined DOP1B as a member of the Dopey leucine-zipper-like family with conserved C-terminal domains, framing a conserved morphogenesis function across phylogeny.\",\n      \"evidence\": \"Comparative sequence analysis and transgenic mouse overexpression with cortical cell density measurement\",\n      \"pmids\": [\"16303751\"],\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"domain assignment is computational with no direct mechanistic follow-up on the leucine-zipper domains\",\n      \"gaps\": [\"Leucine-zipper domain function not tested directly\", \"Overexpression phenotype not mechanistically linked to trafficking\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Resolved the molecular activity by showing DOPEY2 forms a trimeric complex with MON2 and ATP9A required for SNX3-retromer endosome-to-Golgi transport of Wntless, connecting the gene to Wnt signaling.\",\n      \"evidence\": \"Reciprocal Co-IP, in vivo C. elegans RNAi epistasis, and dominant-negative TAT-5(E246Q) overexpression\",\n      \"pmids\": [\"30213940\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and structural basis of the complex unresolved\", \"Direct cargo set beyond Wntless not defined\", \"Catalytic contribution of ATP9A translocase activity to DOPEY2 function unclear\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed how DOPEY2 acts mechanically: it is recruited to recycling endosomes via MON2 and binds kinesin and dynein/dynactin motors to control endosome positioning.\",\n      \"evidence\": \"Live imaging, motor-protein Co-IP, and DOPEY2/MON2 knockout cell lines with organelle distribution readout\",\n      \"pmids\": [\"32404555\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How DOPEY2 switches between opposing motors not defined\", \"Link between positioning defect and retrograde cargo transport not directly tested\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended the developmental role to vertebrate neurogenesis, showing Dopey2 drives neural stem/progenitor proliferation and reciprocally restricts Pcdh7 to shape brain size.\",\n      \"evidence\": \"Zebrafish genetic mutants with neural progenitor proliferation and expression epistasis assays\",\n      \"pmids\": [\"36936789\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking endosomal trafficking to proliferation not established\", \"Nature of Dopey2-Pcdh7 mutual restriction unknown\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked DOP1B to human disease by identifying a homozygous variant segregating with autosomal recessive Peters anomaly and localizing expression to ocular tissues.\",\n      \"evidence\": \"Exome sequencing with segregation analysis and RT-PCR in human eye tissues\",\n      \"pmids\": [\"33273802\"],\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"variant segregation establishes association but no functional experiment confirms causality; single family\",\n      \"gaps\": [\"No functional validation of the variant\", \"Single consanguineous family\", \"Trafficking mechanism linking gene to ocular phenotype untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How DOPEY2's endosomal trafficking and motor-coupling functions mechanistically produce its developmental and disease phenotypes remains unresolved.\",\n      \"evidence\": null,\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the DOPEY2-MON2-ATP9A complex\", \"Cargo repertoire beyond Wntless undefined\", \"Mechanistic bridge from trafficking to neural proliferation and ocular development missing\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 4]}\n    ],\n    \"complexes\": [\"DOPEY2-MON2-ATP9A complex\"],\n    \"partners\": [\"MON2\", \"ATP9A\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}