dyf-2 (C. elegans) — research notes
UniProt: G5ECZ4 (DYF2_CAEEL). Gene: dyf-2 / ift-144 / ZK520.3 (WBGene00001118). 1364 aa.
Human ortholog: WDR19 (= IFT144 in Chlamydomonas). Part of the IFT-A (intraflagellar
transport complex A) machinery. Flagship project: projects/CAEEL_CILIOPATHY.md.
Domain architecture (UniProt/InterPro): N-terminal WD40 β-propeller repeats (WD 1–5) followed by
a long C-terminal TPR (tetratricopeptide) α-solenoid (TPR 1–7). This WD40-propeller + TPR-solenoid
architecture is the signature of the large IFT-A/IFT-B "core" subunits (IFT144/140/122/172/80).
There is no catalytic domain — DYF-2 is a scaffolding/structural subunit.
What is KNOWN (with provenance)
Identity: DYF-2 is the WDR19/IFT144 ortholog, an IFT-A component
- [PMID:16957054 title: "Caenorhabditis elegans DYF-2, an orthologue of human WDR19, is a component
of the intraflagellar transport machinery in sensory cilia."]
- PMID:22922713
- PMID:22922713
- UniProt SUBUNIT: "Component of the IFT complex A (IFT-A) composed of at least che-11, daf-10,
dyf-2, ift-139, ift-43 and ifta-1." ComplexPortal CPX-1289 = Intraflagellar transport complex A.
- Mass-spec identification of DYF-2 in IFT complex A: PMID:28479320 (Yi et al. 2017; UniProt RN[4]:
"IDENTIFICATION IN IFT COMPLEX A, AND IDENTIFICATION BY MASS SPECTROMETRY").
Localization: ciliary; expressed in ciliated sensory neurons
- PMID:16957054
- UniProt SUBCELLULAR LOCATION: Cell projection, cilium. TISSUE SPECIFICITY: ciliated sensory
neurons. C. elegans sensory cilia are non-motile (GO:0097730).
Function: retrograde IFT / IFT turnaround; cilium assembly & integrity
BBSome coupling
Disruption phenotype (UniProt, from PMID:16957054)
Shorter phasmid cilia; mislocalization of IFT-A proteins (che-11) and IFT-B (osm-5); impaired
transport/accumulation of IFT-B che-13; strong osmotic-avoidance (Osm) phenotype; impaired
chemotaxis to volatile odorants (pyrazine, iso-amyl alcohol); dye-filling defective (Dyf).
Curation nuance: IFT-A vs IFT-B complex membership
The 2006 primary paper concluded DYF-2 "can associate with IFT particle complex B"
PMID:16957054 while also noting
"mutations in dyf-2 can interfere with the function of complex A components." This dual/early model
generated the experimental IDA annotation to GO:0030992 intraciliary transport particle B.
The modern consensus firmly places WDR19/IFT144/DYF-2 as a core IFT-A subunit: direct mass-spec
identification in IFT-A (PMID:28479320 / ComplexPortal CPX-1289), the Chlamydomonas IFT144 = IFT-A
assignment PMID:22922713,
and the IFT-A subunit list in UniProt. The 2006 IFT-B "association" reflects DYF-2 functioning at
the IFT-A/IFT-B interface (it reassembles IFT-B into the IFT-A–dynein machinery at the tip), not
stable IFT-B core membership. => GO:0030992 (IFT-B) is best marked as over-annotation/superseded;
GO:0030991 (IFT-A) is the correct, well-supported complex membership.
What is NOT known (knowledge gaps)
- No assigned molecular function / no specific biochemical activity. DYF-2 has WD40 + TPR
protein-interaction folds and no catalytic domain; its "function" is to be a structural
constituent of IFT-A. GO has no "structural constituent of the IFT particle" MF term — an
ontology gap (structural-subunit pattern), so the gene reads MF-dark despite a well-understood
cellular role.
- The IFT-A subunit-level interaction map is undefined in the worm. Which IFT-A neighbours
DYF-2 directly contacts (che-11/IFT140, daf-10/IFT122, ift-139, ift-43, ifta-1) and the
stoichiometry/architecture of worm IFT-A are not experimentally resolved; interactions are
inferred from cross-species proteomics/structures.
- Mechanism of tip reassembly. How the DYF-2 WD40 domain physically "reassembles IFT-B into the
IFT-A–dynein retrograde machinery" at the ciliary tip is a model, not a solved structure/mechanism.
- BBSome-docking interface. The DYF-2/WDR19 surface that docks the BBSome onto moving IFT
particles is inferred from point mutants (G361R worm / G341R mouse) and BiFC/co-IP, not from a
structure of the DYF-2–BBSome interface.
Provisional annotation-review plan (23 GOA annotations)
- Core CC: GO:0030991 (IFT particle A) ACCEPT ×2 (IBA, NAS); GO:0005929 (cilium) ACCEPT ×3;
GO:0097730 (non-motile cilium, IDA) ACCEPT. GO:0030990 (IFT particle, IEA) = generic parent, keep.
- Core BP: GO:0035721 (retrograde IFT) ACCEPT ×4 (IBA, IEA, NAS, IMP); GO:0042073 (IFT, IDA) ACCEPT;
GO:0060271 (cilium assembly) ACCEPT ×3; GO:1905515 (non-motile cilium assembly, IMP) ACCEPT;
GO:0044782 (cilium organization, IEA) = generic parent, keep as non-core.
- GO:0030992 (IFT particle B, IDA PMID:16957054): MARK_AS_OVER_ANNOTATED (superseded; see nuance).
- GO:0008104 (intracellular protein localization) IEA + IMP: MODIFY -> GO:0061512 protein
localization to cilium (more specific/accurate; DYF-2 loss mislocalizes ciliary IFT proteins).
- Sensory-behaviour phenotypes (downstream of ciliary dysfunction, KEEP_AS_NON_CORE): GO:0006935
chemotaxis, GO:0007635 chemosensory behavior, GO:0042048 olfactory behavior.
Deep research provenance
Automated deep research was unavailable for this gene: the falcon deep-research run timed out
and produced no output file, so there is no dyf-2-deep-research-falcon.md (none was fabricated). This
review is instead grounded directly in the UniProt record (G5ECZ4 / DYF2_CAEEL), the QuickGO GOA export
(dyf-2-goa.tsv), the PANTHER family data (PTHR14920), and the primary literature — chiefly the founding
ortholog/IFT-component paper PMID:16957054 and the mechanistic IFT-turnaround/BBSome study
PMID:22922713 (full text available), with the IFT-A mass-spec composition from PMID:28479320.