DNAAF5, also called HEATR2, is a HEAT-repeat protein that supports the cytoplasmic preassembly of outer and inner axonemal dynein arms. It associates with the dynein intermediate chain DNAI2 and early assembly factors, and occupies dynein-containing cytoplasmic particles. These interactions help establish the motor apparatus needed for motile cilia and flagella. Biallelic pathogenic variants cause primary ciliary dyskinesia with dynein-arm defects and impaired airway ciliary beating.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003341 cilium movement | IMP PMID:23040496 Whole-exome capture and sequencing identifies HEATR2 mutatio... | KEEP AS NON CORE | Summary: Dynein assembly supports ciliary beating. Reason: Human mutant airway cells and knockdown cultures have defective dynein arms and impaired beating, with corroborating Chlamydomonas silencing. This is a genuine physiological consequence of DNAAF5 activity. The protein supports cytoplasmic motor preassembly rather than generating the ciliary power stroke, so retain movement as non-core. |
| GO:0005737 cytoplasm | IDA PMID:23040496 Whole-exome capture and sequencing identifies HEATR2 mutatio... | MODIFY | Summary: Resolve cytoplasmic localization into supported pools. Reason: The original human airway observation supports a cytoplasmic pool. Later human early-complex imaging and Xenopus DynAP experiments resolve dynein-containing particles, while human HPA ICC/IF supports cytosol. Refine the broad compartment to these complementary supported pools; neither replacement asserts exclusive localization or retroactively makes the original assay a phase-separation experiment. The original cache is abstract-only; its explicit cytoplasmic/nonciliary observation is retained with independent corroboration. Proposed replacements: cytosol dynein axonemal particle |
| GO:0005737 cytoplasm | IDA PMID:25232951 HEATR2 plays a conserved role in assembly of the ciliary mot... | MODIFY | Summary: Granular cytoplasmic localization has more precise context. Reason: Endogenous HEATR2 is granular throughout human nasal-cell cytoplasm and remains outside the axoneme in the examined developmental stages. Later human assembly-factor colocalization and Xenopus live imaging support the DynAP interpretation; HPA independently establishes cytosol. Use both supported compartments without claiming the 2014 microscopy itself measured condensate behavior. Proposed replacements: cytosol dynein axonemal particle |
| GO:0005737 cytoplasm | IEA GO_REF:0000120 | MODIFY | Summary: The electronic cytoplasm assignment is sound but broad. Reason: The current ARBA00026971 rule matches the target FunFam 1.25.10.10:FF:000547 and assigns cytoplasm. The mouse ortholog and UniProt location mapping agree with the human localization evidence. Refine to the established cytosol and dynein axonemal particle pools, preserving the rule and ortholog provenance rather than treating a broad prediction as erroneous. Proposed replacements: cytosol dynein axonemal particle |
| GO:0005829 cytosol | IDA GO_REF:0000052 | ACCEPT | Summary: A cytosolic pool is experimentally supported. Reason: The HPA target record identifies Q86Y56/ENSG00000164818 and reports supported ICC/IF cytosol in U2OS and ASC52telo cells with antibody HPA060196. This agrees with cytoplasmic preassembly and permits additional particulate pools. Other HPA locations are not evidence of an exclusive cytosolic distribution; the images were not independently reinterpreted. Supporting Evidence: GO_REF:0000052 |
| GO:0030317 flagellated sperm motility | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: Conserved preassembly is required for sperm motility. Reason: The target descends from the asserted Bilateria node PTN000416608 in the actual family tree. Fly HEATR2/CG31320 knockdown causes immotile sperm with defective dynein arms, providing genuine experimental grounding for the conserved physiological role. The saved IBD snapshot does not contain this particular assertion, although current GOA records it; that literal reconstruction limit does not negate the positive donor experiment. Retain as a non-core consequence of dynein preassembly, not a sperm motor activity. Supporting Evidence: |
| GO:0031514 motile cilium | IDA NOT PMID:23040496 Whole-exome capture and sequencing identifies HEATR2 mutatio... | ACCEPT | Summary: The negative ciliary observation is retained. Reason: The source explicitly localizes HEATR2 to human airway-cell cytoplasm rather than cilia. Independent 2014 imaging corroborates the nonaxonemal pool across examined differentiation stages. Preserve the NOT assertion as this scope-limited experimental observation, not a universal claim about all tissues, natural products or engineered constructs. |
| GO:0031514 motile cilium | IDA NOT PMID:25232951 HEATR2 plays a conserved role in assembly of the ciliary mot... | ACCEPT | Summary: Endogenous HEATR2 is not detected in examined motile axonemes. Reason: Human nasal-cell immunofluorescence detects endogenous HEATR2 in the cytoplasm while dynein subunits enter the axoneme. Fly tagged CG31320 and mouse observations corroborate this preassembly localization. Retain the negative motile-cilium assertion with its tested cell/stage scope; no universal absence for every product is inferred. Supporting Evidence: |
| GO:0036158 outer dynein arm assembly | IBA GO_REF:0000033 | ACCEPT | Summary: Conserved outer-arm preassembly is phylogenetically grounded. Reason: The literal PTN000416608 IBD lies on the human lineage, and the target sequence matches its 855-residue family alignment. Human target experiments and fly HEATR2 loss establish outer dynein-arm defects and cytoplasmic preassembly. The target appearing as a donor is legitimate experimental grounding, not circularity. Preserve the inherited assembly role; the effect on individual inner-arm subtypes is not assumed uniform. Supporting Evidence: |
| GO:0036158 outer dynein arm assembly | IMP PMID:23040496 Whole-exome capture and sequencing identifies HEATR2 mutatio... | ACCEPT | Summary: DNAAF5 is required for outer-arm preassembly. Reason: Human mutant and knockdown airway cells lose outer dynein-arm components, while ortholog silencing in Chlamydomonas produces corresponding defects. Later human DNAI2 association and early assembly-factor experiments support performed preassembly work rather than interpreting motility loss alone as the mechanism. Retain the curated outer-arm assembly assertion with the original full-text access limit explicit. |
| GO:0036158 outer dynein arm assembly | IMP PMID:25232951 HEATR2 plays a conserved role in assembly of the ciliary mot... | ACCEPT | Summary: Human and fly data support outer-arm assembly. Reason: Patient respiratory cells lose axonemal DNAH5; fly HEATR2/CG31320 knockdown removes outer arms without abolishing the basic axonemal microtubule arrangement. Endogenous human HEATR2 associates with DNAI2 during the cytoplasmic assembly context. These results support the assembly function, not dynein motor catalysis or an independently established transport activity. Supporting Evidence: |
| GO:0036159 inner dynein arm assembly | IBA GO_REF:0000033 | ACCEPT | Summary: Conserved inner-arm preassembly is phylogenetically grounded. Reason: The literal PTN000416608 IBD lies on the human lineage, and the target sequence matches its 855-residue family alignment. Human target experiments and fly HEATR2 loss establish inner dynein-arm defects and cytoplasmic preassembly. The target appearing as a donor is legitimate experimental grounding, not circularity. Preserve the inherited assembly role; the effect on individual inner-arm subtypes is not assumed uniform. Supporting Evidence: |
| GO:0036159 inner dynein arm assembly | IMP PMID:25232951 HEATR2 plays a conserved role in assembly of the ciliary mot... | ACCEPT | Summary: Inner-arm assembly is a supported component of the same function. Reason: Human patient cells lose DNALI1-positive inner-arm structures, and fly sensory and sperm axonemes show inner-arm defects. This supports DNAAF5-dependent preassembly while leaving its exact inner-arm client interface unresolved. The earlier retained human DNAH7 and differing algal inner-arm effects preclude claiming universal loss of every inner-arm subtype. Supporting Evidence: |
| GO:0045505 dynein intermediate chain binding | IBA GO_REF:0000033 | ACCEPT | Summary: The inherited specific binding assertion has direct target grounding. Reason: PTN000416608 is on the actual human lineage and its literal IBD is grounded in human Q86Y56 evidence. Endogenous HEATR2 co-immunoprecipitates the intermediate chain DNAI2 in human bronchial cultures. Retain the specific curated binding inference while distinguishing cellular association from purified binary affinity or a mapped interface. Supporting Evidence: |
| GO:0045505 dynein intermediate chain binding | IPI PMID:25232951 HEATR2 plays a conserved role in assembly of the ciliary mot... | ACCEPT | Summary: Human DNAI2 association supports the specific binding term. Reason: The imported partner Q9GZS0 is the 605-residue human dynein intermediate chain DNAI2. The original controlled endogenous HEATR2 co-immunoprecipitation and DNAI2 immunoblot use normal human bronchial cells at day 40 of air–liquid-interface culture. This targeted, mechanistically relevant positive assay supports the curated dynein-intermediate-chain binding claim, without asserting purified binary binding. The current IntAct/MINT query did not reproduce this exact source pair; that is an access/projection limit, not negative evidence. Supporting Evidence: PMID:25232951 HEATR2 interacts with DNAI2. |
| GO:0120293 dynein axonemal particle | EXP PMID:23040496 Whole-exome capture and sequencing identifies HEATR2 mutatio... | ACCEPT | Summary: Later evidence identifies the original cytoplasmic assembly pool. Reason: The imported early source establishes a cytoplasmic/nonciliary pool. It predates the DynAP definition and does not by itself establish liquid-like behavior. Human HEATR2/SPAG1/DNAAF2 foci containing dynein subunits, together with direct Xenopus HEATR2 DynAP localization and dynamics, independently support the same gene-level compartment. Retain the annotation with this explicit cross-source corroboration rather than claim that the early experiment used the later terminology. |
| GO:0120293 dynein axonemal particle | EXP PMID:25232951 HEATR2 plays a conserved role in assembly of the ciliary mot... | ACCEPT | Summary: Later evidence identifies the original cytoplasmic assembly pool. Reason: The imported early source establishes a cytoplasmic/nonciliary pool with granular localization. It predates the DynAP definition and does not by itself establish liquid-like behavior. Human HEATR2/SPAG1/DNAAF2 foci containing dynein subunits, together with direct Xenopus HEATR2 DynAP localization and dynamics, independently support the same gene-level compartment. Retain the annotation with this explicit cross-source corroboration rather than claim that the early experiment used the later terminology. |
| GO:0120293 dynein axonemal particle | IBA GO_REF:0000033 | ACCEPT | Summary: DynAP localization is grounded in the actual ancestral assertion. Reason: The literal PTN000416608 IBD is on the human lineage and cites human Q86Y56 and Xenopus A0JMW2. Xenopus GFP-Heatr2/mCherry-Dnaaf5 experiments directly localize the ortholog to dynein/chaperone-containing particles. Human airway foci and the early complex provide target corroboration. Preserve the inherited compartment claim without transferring every Xenopus kinetic measurement to human cells. |
| GO:0120293 dynein axonemal particle | IEA GO_REF:0000044 | ACCEPT | Summary: The UniProt location mapping is supported by independent evidence. Reason: SL-0542 maps to dynein axonemal particle. The early human sources cited by UniProt describe the cytoplasmic pool, whereas later human complex imaging and Xenopus live-cell experiments establish the relevant particle context. These sources support the mapped location; DynAP is a dynamic cytoplasmic compartment rather than proof of a fixed stoichiometric protein complex. |
| GO:0120293 dynein axonemal particle | ISS GO_REF:0000024 | ACCEPT | Summary: The Xenopus donor directly localizes to DynAPs. Reason: A0JMW2 is Xenopus laevis Dnaaf5/Heatr2. Its direct IDA records cite fluorescently tagged ortholog imaging in multiciliated epidermal cells, with colocalization against dynein subunits and other assembly factors. This is genuine donor evidence for the ISS transfer, complemented by human airway HEATR2-containing foci. Species, tag and natural-product limits are retained. Supporting Evidence: PMID:30561330 GFP-Heatr2 was easily detectable in cytosolic foci |
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Download this section (compressed HTML)Q: Which contacts between DNAAF5, DNAI2 and SPAG1 directly stabilize assembly intermediates, and how do these change during ciliogenesis?
Q: Do the three natural DNAAF5 products differ in stability, assembly-factor association or localization?
Q: How do human DNAAF5-containing particles acquire DynAP material properties, and which inner-arm subtypes depend on each assembly step?
Experiment: Compare sequence-verified natural products at matched expression in DNAAF5-deficient human airway cultures, measuring DNAI2 association, outer/inner-arm restoration and particle localization.
Hypothesis: Natural products may differ in assembly competence or subcellular distribution.
Type: Product-resolved complementation and localization
Experiment: Combine purified-component interaction measurements with stage-resolved endogenous complex analysis to separate direct interfaces from developmental co-complex association.
Hypothesis: Developmental assembly complexes combine direct interfaces with transient indirect associations.
Type: Direct binding and stage-resolved complex analysis
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