{"gene":"DAW1","run_date":"2026-06-09T22:57:19","timeline":{"discoveries":[{"year":2008,"finding":"ODA16 (DAW1 ortholog in Chlamydomonas) functions as a cargo-specific adaptor between IFT particles and outer row dynein for efficient dynein transport into flagella. ODA16 localization depends on IFT, and it directly interacts with IFT complex B subunit IFT46, demonstrated by yeast two-hybrid, in vitro pull-down, and co-immunoprecipitation from flagellar extracts. Dynein extracted from wild-type axonemes can rebind to oda16 axonemes in vitro, consistent with a role in transport rather than subunit preassembly or binding-site formation.","method":"Yeast two-hybrid, in vitro pull-down, co-immunoprecipitation, in vitro dynein rebinding assay, IFT-dependent localization analysis","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal methods (Y2H, pull-down, co-IP, functional reconstitution) in a single rigorous study establishing the adaptor mechanism","pmids":["18852297"],"is_preprint":false},{"year":2017,"finding":"Crystal structure of Chlamydomonas ODA16 revealed an 80-residue N-terminal domain and a C-terminal 8-bladed β-propeller domain; both are required for binding to the N-terminal 147 residues of IFT46 (Kd ~200 nM), while only the C-terminal β-propeller is required for interaction with ODAs. This structural mapping defined the architectural model for ODA16-mediated IFT of outer dynein arms.","method":"X-ray crystallography, pull-down assays, dissociation constant measurement, domain mutagenesis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structure combined with quantitative binding assays and domain dissection in a single rigorous study","pmids":["28298440"],"is_preprint":false},{"year":2017,"finding":"The N-terminus of IFT46 is specifically required for intraflagellar transport of outer arm dynein and its cargo-adaptor ODA16 into flagella. A suppressor allele expressing only the IFT46 C-terminal 240 amino acids restores IFT-B stability and flagellar length but fails to import ODA16 or outer arm dynein, establishing that IFT46 N-terminus, ODA16, and outer arm dynein interact for IFT of dynein.","method":"Genetic suppressor analysis, transposon insertion characterization, flagellar protein analysis by immunofluorescence/western blot in Chlamydomonas mutants","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with molecular characterization of suppressor allele, multiple orthogonal readouts, independently consistent with structural data from PMID:28298440","pmids":["28701346"],"is_preprint":false},{"year":2020,"finding":"The crystal structure of human ODA16 (DAW1) shows a C-terminal 8-bladed β-propeller with high overall structural similarity to Chlamydomonas ODA16, but the N-terminal domain has no visible electron density. Notably, size exclusion chromatography and pull-down experiments failed to detect a direct interaction between human ODA16 and IFT46, suggesting that additional factors are required for ciliary import of ODAs in human cells.","method":"X-ray crystallography, size exclusion chromatography, pull-down experiments with recombinant human proteins","journal":"Protein science : a publication of the Protein Society","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — crystal structure and direct binding assays in single lab; negative interaction result is mechanistically informative, suggesting divergent mechanism in humans","pmids":["32239748"],"is_preprint":false},{"year":2020,"finding":"Planarian Smed-DAW1 (ortholog of DAW1) is required for motile cilia function in multiciliated epidermis and protonephridia. RNAi knockdown caused locomotion defects and edema without initial loss of cilia number or length, indicating DAW1 loss impairs cilia motility rather than ciliogenesis per se. Extended RNAi resulted in shorter epidermal cilia and fewer ciliated protonephridia, indicating a role in homeostatic maintenance of ciliated structures.","method":"Systemic RNAi knockdown in planarian Schmidtea mediterranea, phenotypic analysis (locomotion, edema), cilia morphology assessment","journal":"Development, growth & differentiation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean loss-of-function with specific phenotypic readouts in two distinct ciliated tissues, single lab","pmids":["32359074"],"is_preprint":false},{"year":2022,"finding":"Zebrafish Daw1 facilitates the timely onset of robust cilia motility during early development. daw1 mutants show markedly reduced cilia motility during early development that subsequently recovers toward wild-type levels; the early motility deficit leads to laterality defects and body axis curves that self-correct when motility recovers, while later cilia-dependent processes are less affected.","method":"Zebrafish daw1 mutant analysis, cilia motility imaging, left-right patterning phenotype assessment","journal":"Development (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo loss-of-function with quantitative cilia motility readout, single lab, clear developmental phenotype","pmids":["35708608"],"is_preprint":false},{"year":2022,"finding":"Biallelic DAW1 loss-of-function in humans causes distal type 2 outer dynein arm assembly defects in axonemal respiratory cilia proteins, explaining reduced cilia-induced fluid flow. Pathogenic DAW1 missense variants display reduced protein stability. In zebrafish, daw1 mutants showed reduced cilia motility and left-right patterning defects rescued by wild-type but not mutant daw1 expression. In early mouse embryos, Daw1 expression is limited to distal motile ciliated cells of the node.","method":"Genomic variant identification, electron microscopy of ciliary ultrastructure, particle tracking velocimetry, zebrafish rescue experiments with wild-type vs. mutant daw1, mouse embryo expression analysis, protein stability assessment","journal":"Genetics in medicine : official journal of the American College of Medical Genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods across human, zebrafish, and mouse with functional rescue experiments confirming specificity of variants","pmids":["36074124"],"is_preprint":false},{"year":2024,"finding":"Active ARL3 GTPases in Trypanosoma brucei cilia bind ODA16 and dissociate it from the IFT complex, functioning as a cargo-unloading mechanism. Depletion of ARL3 stabilizes ODA16–IFT interaction, causing ODA16 accumulation in cilia and defects in axonemal assembly. Interactions between human DAW1 (HsDAW1) and ARL GTPases are conserved, and these interactions are altered in HsDAW1 disease variants.","method":"ARL3 depletion in T. brucei (RNAi), co-immunoprecipitation, ciliary protein localization analysis, conservation study with human DAW1 and ARL GTPases, disease variant functional testing","journal":"Science advances","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP and loss-of-function with defined phenotype, conservation confirmed for human DAW1, single lab","pmids":["39231220"],"is_preprint":false},{"year":2025,"finding":"In silico AlphaPulldown screening identified IDA3 and Arl3 as direct interactors of ODA16. Biochemical and biophysical assays showed that a conserved N-terminal motif in IFT46 binds one face of the ODA16 structure, while IDA3 and Arl3 bind the opposite face (C-terminal β-propeller), enabling them to dissociate ODA16 from IFT46 through an allosteric mechanism, thereby releasing ODA cargo from the IFT machinery.","method":"AlphaPulldown in silico screening, structural modeling, biochemical binding assays, biophysical assays on Chlamydomonas and human proteins","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — structural modeling combined with biochemical/biophysical validation, single lab, mechanistically detailed","pmids":["39880089"],"is_preprint":false}],"current_model":"DAW1 (ODA16) is a WD-repeat/β-propeller adaptor protein that facilitates intraflagellar transport (IFT) of outer dynein arms (ODAs) into motile cilia by binding directly to IFT46 via its N-terminal domain (with the IFT46 N-terminus required on the other side), while its C-terminal β-propeller contacts ODAs; once inside the cilium, active ARL3 GTPases bind the β-propeller face opposite the IFT46 binding site and allosterically release DAW1/ODA16 from the IFT complex, unloading the dynein cargo for axonemal assembly—loss of DAW1 causes outer dynein arm assembly defects, reduced cilia motility, and laterality abnormalities in vertebrates."},"narrative":{"mechanistic_narrative":"DAW1 (ODA16) is a WD-repeat/β-propeller cargo-adaptor that couples outer dynein arms (ODAs) to the intraflagellar transport (IFT) machinery for delivery into motile cilia, and its loss produces ODA assembly defects, reduced cilia motility, and laterality abnormalities [PMID:18852297, PMID:36074124]. In Chlamydomonas, ODA16 acts as a cargo-specific adaptor that binds IFT complex-B subunit IFT46 and bridges it to outer-row dynein, enabling efficient dynein transport rather than dynein preassembly [PMID:18852297]. Structurally, the protein comprises a short N-terminal domain and a C-terminal eight-bladed β-propeller; both segments engage the N-terminal ~147 residues of IFT46, whereas the β-propeller alone contacts ODAs [PMID:28298440], and the IFT46 N-terminus is reciprocally required for IFT of ODA16 and outer-arm dynein [PMID:28701346]. Cargo unloading is achieved by active ARL3 GTPases (and IDA3), which bind the β-propeller face opposite the IFT46 site and allosterically dissociate ODA16 from the IFT complex; depleting ARL3 traps ODA16 on IFT and impairs axonemal assembly [PMID:39231220, PMID:39880089]. Across vertebrates, DAW1 is required for the timely onset of robust cilia motility and correct left-right patterning [PMID:35708608], and biallelic loss-of-function variants in humans cause distal outer dynein arm assembly defects with destabilized protein, establishing DAW1 as a motile ciliopathy gene [PMID:36074124]. Notably, the human protein retains the β-propeller fold but a direct DAW1–IFT46 interaction was not detected biochemically, indicating additional factors operate in human ODA import [PMID:32239748].","teleology":[{"year":2008,"claim":"Established that ODA16/DAW1 is a cargo-specific adaptor linking IFT particles to outer-arm dynein, answering whether it transports dynein versus building or pre-assembling it.","evidence":"Yeast two-hybrid, in vitro pull-down, co-IP from flagellar extracts, and in vitro dynein rebinding in Chlamydomonas oda16 mutants","pmids":["18852297"],"confidence":"High","gaps":["No structural basis for the IFT46 or dynein interaction","Mechanism of cargo release within the cilium unknown"]},{"year":2017,"claim":"Defined the domain architecture and binding surfaces, showing the N-terminal domain plus C-terminal β-propeller bind IFT46 while only the β-propeller contacts ODAs.","evidence":"X-ray crystallography of Chlamydomonas ODA16 with pull-down, Kd measurement (~200 nM), and domain mutagenesis; complemented by genetic suppressor analysis mapping the requirement to the IFT46 N-terminus","pmids":["28298440","28701346"],"confidence":"High","gaps":["Structure of the ODA16–IFT46 or ODA16–ODA complex not solved","Trigger for cargo unloading not yet identified"]},{"year":2020,"claim":"Tested conservation of the mechanism in humans and in whole-organism cilia function, revealing the β-propeller is conserved but the direct DAW1–IFT46 contact is not biochemically detectable, and that DAW1 loss impairs motility before ciliogenesis.","evidence":"Crystallography, SEC and pull-downs with recombinant human DAW1/IFT46; systemic RNAi in planarian Schmidtea mediterranea with cilia morphology and locomotion readouts","pmids":["32239748","32359074"],"confidence":"Medium","gaps":["Identity of additional factors required for human ODA import unknown","Why the human N-terminal domain is disordered/non-binding unresolved"]},{"year":2022,"claim":"Linked DAW1 to vertebrate development and human disease, establishing it as a motile ciliopathy gene causing distal ODA assembly defects and laterality abnormalities.","evidence":"Zebrafish daw1 mutant motility imaging and left-right patterning with wild-type vs mutant rescue, human genomic variant identification with ciliary EM and particle tracking velocimetry, mouse node expression, and protein stability assays","pmids":["35708608","36074124"],"confidence":"High","gaps":["Molecular basis of variant-induced instability not defined at structural level","Why early motility deficit self-corrects in zebrafish unexplained"]},{"year":2024,"claim":"Identified the cargo-unloading mechanism, showing active ARL3 GTPases dissociate ODA16 from IFT to release dynein cargo within the cilium.","evidence":"ARL3 RNAi in Trypanosoma brucei with co-IP and ciliary localization, plus conservation testing of human DAW1–ARL interactions and disease variants","pmids":["39231220"],"confidence":"Medium","gaps":["Single-organism mechanism; in vivo human validation limited","Spatial/temporal control of ARL3 activation in cilia unknown"]},{"year":2025,"claim":"Resolved the allosteric logic of unloading, mapping IFT46 to one face of ODA16 and IDA3/Arl3 to the opposite β-propeller face to drive release.","evidence":"AlphaPulldown in silico screening with structural modeling and biochemical/biophysical binding assays on Chlamydomonas and human proteins","pmids":["39880089"],"confidence":"Medium","gaps":["Predominantly computational/biochemical without high-resolution co-complex structure","How IDA3 versus Arl3 roles are coordinated in vivo unclear"]},{"year":null,"claim":"The full human ODA import pathway, including the additional factors substituting for the missing direct DAW1–IFT46 contact, remains undefined.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No identified human-specific bridging factor for ODA import","No high-resolution structure of the loaded or unloaded human DAW1–IFT–dynein assembly"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,1]},{"term_id":"GO:0038024","term_label":"cargo receptor activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[0,2,7]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[0,2]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,2]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[0,6]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[5,6]}],"complexes":[],"partners":["IFT46","ARL3","IDA3"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8N136","full_name":"Dynein assembly factor with WD repeat domains 1","aliases":["Outer row dynein assembly protein 16 homolog","WD repeat-containing protein 69"],"length_aa":415,"mass_kda":45.8,"function":"Required for axonemal dynein assembly and ciliary motility in ciliated organs, including Kupffer's vesicle, during embryogenesis (PubMed:36074124). Facilitates the onset of robust cilia motility during development (PubMed:36074124)","subcellular_location":"Cytoplasm, cytoskeleton, flagellum basal body; Cytoplasm, cytoskeleton, flagellum axoneme","url":"https://www.uniprot.org/uniprotkb/Q8N136/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/DAW1","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/DAW1","total_profiled":1310},"omim":[{"mim_id":"620570","title":"CILIARY DYSKINESIA, PRIMARY, 52; CILD52","url":"https://www.omim.org/entry/620570"},{"mim_id":"620279","title":"DYNEIN ASSEMBLY FACTOR WITH WD REPEATS 1; DAW1","url":"https://www.omim.org/entry/620279"},{"mim_id":"244400","title":"CILIARY DYSKINESIA, PRIMARY, 1; CILD1","url":"https://www.omim.org/entry/244400"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Mid piece","reliability":"Approved"},{"location":"Principal piece","reliability":"Approved"},{"location":"End piece","reliability":"Approved"},{"location":"Plasma membrane","reliability":"Additional"}],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"choroid plexus","ntpm":55.4},{"tissue":"fallopian tube","ntpm":30.8},{"tissue":"testis","ntpm":48.2}],"url":"https://www.proteinatlas.org/search/DAW1"},"hgnc":{"alias_symbol":["FLJ25955","ODA16","DNAAF18"],"prev_symbol":["WDR69"]},"alphafold":{"accession":"Q8N136","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N136","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N136-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N136-F1-predicted_aligned_error_v6.png","plddt_mean":96.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=DAW1","jax_strain_url":"https://www.jax.org/strain/search?query=DAW1"},"sequence":{"accession":"Q8N136","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8N136.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8N136/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N136"}},"corpus_meta":[{"pmid":"18852297","id":"PMC_18852297","title":"ODA16 aids axonemal outer row dynein assembly through an interaction with the intraflagellar transport machinery.","date":"2008","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/18852297","citation_count":136,"is_preprint":false},{"pmid":"28298440","id":"PMC_28298440","title":"Structural basis of outer dynein arm intraflagellar transport by the transport adaptor protein ODA16 and the intraflagellar transport protein IFT46.","date":"2017","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/28298440","citation_count":44,"is_preprint":false},{"pmid":"28701346","id":"PMC_28701346","title":"The N-terminus of IFT46 mediates intraflagellar transport of outer arm dynein and its cargo-adaptor ODA16.","date":"2017","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/28701346","citation_count":35,"is_preprint":false},{"pmid":"32359074","id":"PMC_32359074","title":"Dynein assembly factor with WD repeat domains 1 (DAW1) is required for the function of motile cilia in the planarian Schmidtea mediterranea.","date":"2020","source":"Development, growth & differentiation","url":"https://pubmed.ncbi.nlm.nih.gov/32359074","citation_count":17,"is_preprint":false},{"pmid":"32239748","id":"PMC_32239748","title":"Purification and crystal structure of human ODA16: Implications for ciliary import of outer dynein arms by the intraflagellar transport machinery.","date":"2020","source":"Protein science : a publication of the Protein Society","url":"https://pubmed.ncbi.nlm.nih.gov/32239748","citation_count":12,"is_preprint":false},{"pmid":"35708608","id":"PMC_35708608","title":"Daw1 regulates the timely onset of cilia motility during development.","date":"2022","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/35708608","citation_count":11,"is_preprint":false},{"pmid":"36074124","id":"PMC_36074124","title":"Biallelic DAW1 variants cause a motile ciliopathy characterized by laterality defects and subtle ciliary beating abnormalities.","date":"2022","source":"Genetics in medicine : official journal of the American College of Medical Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36074124","citation_count":10,"is_preprint":false},{"pmid":"39231220","id":"PMC_39231220","title":"ARL3 GTPases facilitate ODA16 unloading from IFT in motile cilia.","date":"2024","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/39231220","citation_count":9,"is_preprint":false},{"pmid":"29175859","id":"PMC_29175859","title":"Investigating trehalose synthesis genes after cold acclimation in the Antarctic nematode Panagrolaimus sp. DAW1.","date":"2017","source":"Biology open","url":"https://pubmed.ncbi.nlm.nih.gov/29175859","citation_count":9,"is_preprint":false},{"pmid":"27832164","id":"PMC_27832164","title":"Establishing RNAi in a Non-Model Organism: The Antarctic Nematode Panagrolaimus sp. DAW1.","date":"2016","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/27832164","citation_count":5,"is_preprint":false},{"pmid":"39880089","id":"PMC_39880089","title":"Integrative in silico and biochemical analyses demonstrate direct Arl3-mediated ODA16 release from the intraflagellar transport machinery.","date":"2025","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/39880089","citation_count":3,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7445,"output_tokens":2649,"usd":0.031035,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9886,"output_tokens":2676,"usd":0.058165,"stage2_stop_reason":"end_turn"},"total_usd":0.0892,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2008,\n      \"finding\": \"ODA16 (DAW1 ortholog in Chlamydomonas) functions as a cargo-specific adaptor between IFT particles and outer row dynein for efficient dynein transport into flagella. ODA16 localization depends on IFT, and it directly interacts with IFT complex B subunit IFT46, demonstrated by yeast two-hybrid, in vitro pull-down, and co-immunoprecipitation from flagellar extracts. Dynein extracted from wild-type axonemes can rebind to oda16 axonemes in vitro, consistent with a role in transport rather than subunit preassembly or binding-site formation.\",\n      \"method\": \"Yeast two-hybrid, in vitro pull-down, co-immunoprecipitation, in vitro dynein rebinding assay, IFT-dependent localization analysis\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal methods (Y2H, pull-down, co-IP, functional reconstitution) in a single rigorous study establishing the adaptor mechanism\",\n      \"pmids\": [\"18852297\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Crystal structure of Chlamydomonas ODA16 revealed an 80-residue N-terminal domain and a C-terminal 8-bladed β-propeller domain; both are required for binding to the N-terminal 147 residues of IFT46 (Kd ~200 nM), while only the C-terminal β-propeller is required for interaction with ODAs. This structural mapping defined the architectural model for ODA16-mediated IFT of outer dynein arms.\",\n      \"method\": \"X-ray crystallography, pull-down assays, dissociation constant measurement, domain mutagenesis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structure combined with quantitative binding assays and domain dissection in a single rigorous study\",\n      \"pmids\": [\"28298440\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"The N-terminus of IFT46 is specifically required for intraflagellar transport of outer arm dynein and its cargo-adaptor ODA16 into flagella. A suppressor allele expressing only the IFT46 C-terminal 240 amino acids restores IFT-B stability and flagellar length but fails to import ODA16 or outer arm dynein, establishing that IFT46 N-terminus, ODA16, and outer arm dynein interact for IFT of dynein.\",\n      \"method\": \"Genetic suppressor analysis, transposon insertion characterization, flagellar protein analysis by immunofluorescence/western blot in Chlamydomonas mutants\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with molecular characterization of suppressor allele, multiple orthogonal readouts, independently consistent with structural data from PMID:28298440\",\n      \"pmids\": [\"28701346\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The crystal structure of human ODA16 (DAW1) shows a C-terminal 8-bladed β-propeller with high overall structural similarity to Chlamydomonas ODA16, but the N-terminal domain has no visible electron density. Notably, size exclusion chromatography and pull-down experiments failed to detect a direct interaction between human ODA16 and IFT46, suggesting that additional factors are required for ciliary import of ODAs in human cells.\",\n      \"method\": \"X-ray crystallography, size exclusion chromatography, pull-down experiments with recombinant human proteins\",\n      \"journal\": \"Protein science : a publication of the Protein Society\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure and direct binding assays in single lab; negative interaction result is mechanistically informative, suggesting divergent mechanism in humans\",\n      \"pmids\": [\"32239748\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Planarian Smed-DAW1 (ortholog of DAW1) is required for motile cilia function in multiciliated epidermis and protonephridia. RNAi knockdown caused locomotion defects and edema without initial loss of cilia number or length, indicating DAW1 loss impairs cilia motility rather than ciliogenesis per se. Extended RNAi resulted in shorter epidermal cilia and fewer ciliated protonephridia, indicating a role in homeostatic maintenance of ciliated structures.\",\n      \"method\": \"Systemic RNAi knockdown in planarian Schmidtea mediterranea, phenotypic analysis (locomotion, edema), cilia morphology assessment\",\n      \"journal\": \"Development, growth & differentiation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean loss-of-function with specific phenotypic readouts in two distinct ciliated tissues, single lab\",\n      \"pmids\": [\"32359074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Zebrafish Daw1 facilitates the timely onset of robust cilia motility during early development. daw1 mutants show markedly reduced cilia motility during early development that subsequently recovers toward wild-type levels; the early motility deficit leads to laterality defects and body axis curves that self-correct when motility recovers, while later cilia-dependent processes are less affected.\",\n      \"method\": \"Zebrafish daw1 mutant analysis, cilia motility imaging, left-right patterning phenotype assessment\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo loss-of-function with quantitative cilia motility readout, single lab, clear developmental phenotype\",\n      \"pmids\": [\"35708608\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Biallelic DAW1 loss-of-function in humans causes distal type 2 outer dynein arm assembly defects in axonemal respiratory cilia proteins, explaining reduced cilia-induced fluid flow. Pathogenic DAW1 missense variants display reduced protein stability. In zebrafish, daw1 mutants showed reduced cilia motility and left-right patterning defects rescued by wild-type but not mutant daw1 expression. In early mouse embryos, Daw1 expression is limited to distal motile ciliated cells of the node.\",\n      \"method\": \"Genomic variant identification, electron microscopy of ciliary ultrastructure, particle tracking velocimetry, zebrafish rescue experiments with wild-type vs. mutant daw1, mouse embryo expression analysis, protein stability assessment\",\n      \"journal\": \"Genetics in medicine : official journal of the American College of Medical Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods across human, zebrafish, and mouse with functional rescue experiments confirming specificity of variants\",\n      \"pmids\": [\"36074124\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Active ARL3 GTPases in Trypanosoma brucei cilia bind ODA16 and dissociate it from the IFT complex, functioning as a cargo-unloading mechanism. Depletion of ARL3 stabilizes ODA16–IFT interaction, causing ODA16 accumulation in cilia and defects in axonemal assembly. Interactions between human DAW1 (HsDAW1) and ARL GTPases are conserved, and these interactions are altered in HsDAW1 disease variants.\",\n      \"method\": \"ARL3 depletion in T. brucei (RNAi), co-immunoprecipitation, ciliary protein localization analysis, conservation study with human DAW1 and ARL GTPases, disease variant functional testing\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP and loss-of-function with defined phenotype, conservation confirmed for human DAW1, single lab\",\n      \"pmids\": [\"39231220\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In silico AlphaPulldown screening identified IDA3 and Arl3 as direct interactors of ODA16. Biochemical and biophysical assays showed that a conserved N-terminal motif in IFT46 binds one face of the ODA16 structure, while IDA3 and Arl3 bind the opposite face (C-terminal β-propeller), enabling them to dissociate ODA16 from IFT46 through an allosteric mechanism, thereby releasing ODA cargo from the IFT machinery.\",\n      \"method\": \"AlphaPulldown in silico screening, structural modeling, biochemical binding assays, biophysical assays on Chlamydomonas and human proteins\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — structural modeling combined with biochemical/biophysical validation, single lab, mechanistically detailed\",\n      \"pmids\": [\"39880089\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"DAW1 (ODA16) is a WD-repeat/β-propeller adaptor protein that facilitates intraflagellar transport (IFT) of outer dynein arms (ODAs) into motile cilia by binding directly to IFT46 via its N-terminal domain (with the IFT46 N-terminus required on the other side), while its C-terminal β-propeller contacts ODAs; once inside the cilium, active ARL3 GTPases bind the β-propeller face opposite the IFT46 binding site and allosterically release DAW1/ODA16 from the IFT complex, unloading the dynein cargo for axonemal assembly—loss of DAW1 causes outer dynein arm assembly defects, reduced cilia motility, and laterality abnormalities in vertebrates.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"DAW1 (ODA16) is a WD-repeat/β-propeller cargo-adaptor that couples outer dynein arms (ODAs) to the intraflagellar transport (IFT) machinery for delivery into motile cilia, and its loss produces ODA assembly defects, reduced cilia motility, and laterality abnormalities [#0, #6]. In Chlamydomonas, ODA16 acts as a cargo-specific adaptor that binds IFT complex-B subunit IFT46 and bridges it to outer-row dynein, enabling efficient dynein transport rather than dynein preassembly [#0]. Structurally, the protein comprises a short N-terminal domain and a C-terminal eight-bladed β-propeller; both segments engage the N-terminal ~147 residues of IFT46, whereas the β-propeller alone contacts ODAs [#1], and the IFT46 N-terminus is reciprocally required for IFT of ODA16 and outer-arm dynein [#2]. Cargo unloading is achieved by active ARL3 GTPases (and IDA3), which bind the β-propeller face opposite the IFT46 site and allosterically dissociate ODA16 from the IFT complex; depleting ARL3 traps ODA16 on IFT and impairs axonemal assembly [#7, #8]. Across vertebrates, DAW1 is required for the timely onset of robust cilia motility and correct left-right patterning [#5], and biallelic loss-of-function variants in humans cause distal outer dynein arm assembly defects with destabilized protein, establishing DAW1 as a motile ciliopathy gene [#6]. Notably, the human protein retains the β-propeller fold but a direct DAW1–IFT46 interaction was not detected biochemically, indicating additional factors operate in human ODA import [#3].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Established that ODA16/DAW1 is a cargo-specific adaptor linking IFT particles to outer-arm dynein, answering whether it transports dynein versus building or pre-assembling it.\",\n      \"evidence\": \"Yeast two-hybrid, in vitro pull-down, co-IP from flagellar extracts, and in vitro dynein rebinding in Chlamydomonas oda16 mutants\",\n      \"pmids\": [\"18852297\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural basis for the IFT46 or dynein interaction\", \"Mechanism of cargo release within the cilium unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defined the domain architecture and binding surfaces, showing the N-terminal domain plus C-terminal β-propeller bind IFT46 while only the β-propeller contacts ODAs.\",\n      \"evidence\": \"X-ray crystallography of Chlamydomonas ODA16 with pull-down, Kd measurement (~200 nM), and domain mutagenesis; complemented by genetic suppressor analysis mapping the requirement to the IFT46 N-terminus\",\n      \"pmids\": [\"28298440\", \"28701346\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure of the ODA16–IFT46 or ODA16–ODA complex not solved\", \"Trigger for cargo unloading not yet identified\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Tested conservation of the mechanism in humans and in whole-organism cilia function, revealing the β-propeller is conserved but the direct DAW1–IFT46 contact is not biochemically detectable, and that DAW1 loss impairs motility before ciliogenesis.\",\n      \"evidence\": \"Crystallography, SEC and pull-downs with recombinant human DAW1/IFT46; systemic RNAi in planarian Schmidtea mediterranea with cilia morphology and locomotion readouts\",\n      \"pmids\": [\"32239748\", \"32359074\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Identity of additional factors required for human ODA import unknown\", \"Why the human N-terminal domain is disordered/non-binding unresolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Linked DAW1 to vertebrate development and human disease, establishing it as a motile ciliopathy gene causing distal ODA assembly defects and laterality abnormalities.\",\n      \"evidence\": \"Zebrafish daw1 mutant motility imaging and left-right patterning with wild-type vs mutant rescue, human genomic variant identification with ciliary EM and particle tracking velocimetry, mouse node expression, and protein stability assays\",\n      \"pmids\": [\"35708608\", \"36074124\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of variant-induced instability not defined at structural level\", \"Why early motility deficit self-corrects in zebrafish unexplained\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified the cargo-unloading mechanism, showing active ARL3 GTPases dissociate ODA16 from IFT to release dynein cargo within the cilium.\",\n      \"evidence\": \"ARL3 RNAi in Trypanosoma brucei with co-IP and ciliary localization, plus conservation testing of human DAW1–ARL interactions and disease variants\",\n      \"pmids\": [\"39231220\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-organism mechanism; in vivo human validation limited\", \"Spatial/temporal control of ARL3 activation in cilia unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved the allosteric logic of unloading, mapping IFT46 to one face of ODA16 and IDA3/Arl3 to the opposite β-propeller face to drive release.\",\n      \"evidence\": \"AlphaPulldown in silico screening with structural modeling and biochemical/biophysical binding assays on Chlamydomonas and human proteins\",\n      \"pmids\": [\"39880089\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Predominantly computational/biochemical without high-resolution co-complex structure\", \"How IDA3 versus Arl3 roles are coordinated in vivo unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The full human ODA import pathway, including the additional factors substituting for the missing direct DAW1–IFT46 contact, remains undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No identified human-specific bridging factor for ODA import\", \"No high-resolution structure of the loaded or unloaded human DAW1–IFT–dynein assembly\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0038024\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [0, 2, 7]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 6]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [5, 6]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"IFT46\", \"ARL3\", \"IDA3\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":6,"faith_total":6,"faith_pct":100.0}}