Affinage

DAW1

Dynein assembly factor with WD repeat domains 1 · UniProt Q8N136

Length
415 aa
Mass
45.8 kDa
Annotated
2026-06-09
11 papers in source corpus 9 papers cited in narrative 9 extracted findings
Cross-family judge vs UniProt: tie faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

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).

Mechanistic history

Synthesis pass · year-by-year structured walk · 6 steps
  1. 2008 High

    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

    PMID:18852297

    Open questions at the time
    • No structural basis for the IFT46 or dynein interaction
    • Mechanism of cargo release within the cilium unknown
  2. 2017 High

    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

    PMID:28298440 PMID:28701346

    Open questions at the time
    • Structure of the ODA16–IFT46 or ODA16–ODA complex not solved
    • Trigger for cargo unloading not yet identified
  3. 2020 Medium

    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

    PMID:32239748 PMID:32359074

    Open questions at the time
    • Identity of additional factors required for human ODA import unknown
    • Why the human N-terminal domain is disordered/non-binding unresolved
  4. 2022 High

    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

    PMID:35708608 PMID:36074124

    Open questions at the time
    • Molecular basis of variant-induced instability not defined at structural level
    • Why early motility deficit self-corrects in zebrafish unexplained
  5. 2024 Medium

    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

    PMID:39231220

    Open questions at the time
    • Single-organism mechanism; in vivo human validation limited
    • Spatial/temporal control of ARL3 activation in cilia unknown
  6. 2025 Medium

    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

    PMID:39880089

    Open questions at the time
    • Predominantly computational/biochemical without high-resolution co-complex structure
    • How IDA3 versus Arl3 roles are coordinated in vivo unclear

Open questions

Synthesis pass · forward-looking unresolved questions
  • The full human ODA import pathway, including the additional factors substituting for the missing direct DAW1–IFT46 contact, remains undefined.
  • 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

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0008092 cytoskeletal protein binding 2 GO:0060090 molecular adaptor activity 2 GO:0038024 cargo receptor activity 1
Localization
GO:0005929 cilium 3 GO:0005856 cytoskeleton 2
Pathway
R-HSA-1266738 Developmental Biology 2 R-HSA-1852241 Organelle biogenesis and maintenance 2 R-HSA-5653656 Vesicle-mediated transport 2
Partners

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2008 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. Yeast two-hybrid, in vitro pull-down, co-immunoprecipitation, in vitro dynein rebinding assay, IFT-dependent localization analysis The Journal of cell biology High 18852297
2017 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. X-ray crystallography, pull-down assays, dissociation constant measurement, domain mutagenesis The Journal of biological chemistry High 28298440
2017 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. Genetic suppressor analysis, transposon insertion characterization, flagellar protein analysis by immunofluorescence/western blot in Chlamydomonas mutants Molecular biology of the cell High 28701346
2020 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. X-ray crystallography, size exclusion chromatography, pull-down experiments with recombinant human proteins Protein science : a publication of the Protein Society Medium 32239748
2020 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. Systemic RNAi knockdown in planarian Schmidtea mediterranea, phenotypic analysis (locomotion, edema), cilia morphology assessment Development, growth & differentiation Medium 32359074
2022 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. Zebrafish daw1 mutant analysis, cilia motility imaging, left-right patterning phenotype assessment Development (Cambridge, England) Medium 35708608
2022 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. 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 Genetics in medicine : official journal of the American College of Medical Genetics High 36074124
2024 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. ARL3 depletion in T. brucei (RNAi), co-immunoprecipitation, ciliary protein localization analysis, conservation study with human DAW1 and ARL GTPases, disease variant functional testing Science advances Medium 39231220
2025 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. AlphaPulldown in silico screening, structural modeling, biochemical binding assays, biophysical assays on Chlamydomonas and human proteins The Journal of biological chemistry Medium 39880089

Source papers

Stage 0 corpus · 11 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2008 ODA16 aids axonemal outer row dynein assembly through an interaction with the intraflagellar transport machinery. The Journal of cell biology 136 18852297
2017 Structural basis of outer dynein arm intraflagellar transport by the transport adaptor protein ODA16 and the intraflagellar transport protein IFT46. The Journal of biological chemistry 44 28298440
2017 The N-terminus of IFT46 mediates intraflagellar transport of outer arm dynein and its cargo-adaptor ODA16. Molecular biology of the cell 35 28701346
2020 Dynein assembly factor with WD repeat domains 1 (DAW1) is required for the function of motile cilia in the planarian Schmidtea mediterranea. Development, growth & differentiation 17 32359074
2020 Purification and crystal structure of human ODA16: Implications for ciliary import of outer dynein arms by the intraflagellar transport machinery. Protein science : a publication of the Protein Society 12 32239748
2022 Daw1 regulates the timely onset of cilia motility during development. Development (Cambridge, England) 11 35708608
2022 Biallelic DAW1 variants cause a motile ciliopathy characterized by laterality defects and subtle ciliary beating abnormalities. Genetics in medicine : official journal of the American College of Medical Genetics 10 36074124
2024 ARL3 GTPases facilitate ODA16 unloading from IFT in motile cilia. Science advances 9 39231220
2017 Investigating trehalose synthesis genes after cold acclimation in the Antarctic nematode Panagrolaimus sp. DAW1. Biology open 9 29175859
2016 Establishing RNAi in a Non-Model Organism: The Antarctic Nematode Panagrolaimus sp. DAW1. PloS one 5 27832164
2025 Integrative in silico and biochemical analyses demonstrate direct Arl3-mediated ODA16 release from the intraflagellar transport machinery. The Journal of biological chemistry 3 39880089

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