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The dyf-3 gene (C04C3.5) in Caenorhabditis elegans encodes a 438-amino-acid protein (UniProt Q6I6D4) that is the ortholog of human clusterin-associated protein 1 (CLUAP1), now systematically designated IFT38 (intraflagellar transport protein 38) (sun2025multipleregulatorsconstrain pages 4-6, pasek2012mammalianclusterinassociated pages 1-2). The protein belongs to the CLUAP1 family and contains a characteristic Cluap1 domain (Pfam PF10234/IPR019366). In zebrafish, the ortholog is known as Qilin, while in mammals it is designated CLUAP1 or IFT38 (pasek2012mammalianclusterinassociated pages 1-2, pasek2012mammalianclusterinassociated pages 2-4). The gene was originally identified through forward genetic screens in C. elegans for dye-filling defective (Dyf) mutants—animals unable to take up fluorescent dyes into their amphid and phasmid sensory neurons—indicating structural or functional defects in sensory cilia (efimenko2006caenorhabditiselegansdyf2an pages 2-3).
DYF-3/CLUAP1/IFT38 is not an enzyme or transporter; rather, it functions as a structural/adaptor protein within the intraflagellar transport (IFT) machinery. Specifically, IFT38 is a subunit of the IFT-B2 (peripheral) subcomplex of the IFT-B complex, which is essential for anterograde ciliary transport—the movement of cargo from the ciliary base toward the tip, powered by kinesin-II motors (taschner2016intraflagellartransportproteins pages 1-2, tasaki2025assemblyandmother pages 1-5, wang2017structuralandbiochemical pages 29-33).
The 16-subunit IFT-B complex is divided into two subcomplexes: IFT-B1 (core, ~10 subunits) and IFT-B2 (peripheral, 6 subunits: IFT172, IFT80, IFT57, IFT54, IFT38, and IFT20) (taschner2016intraflagellartransportproteins pages 1-2, wang2017structuralandbiochemical pages 29-33). Biochemical reconstitution studies using recombinant Chlamydomonas reinhardtii proteins demonstrated that IFT38 contains an N-terminal calponin homology (CH) domain followed by a C-terminal coiled-coil region (taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 1-2). The CH domain of IFT38 mediates a direct interaction with IFT80, while the CH domain of its binding partner IFT57 contacts IFT172 (taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 1-2, taschner2016intraflagellartransportproteins pages 5-5). Unlike the CH domain of IFT54, which binds αβ-tubulin as a potential IFT cargo, the CH domain of IFT38 does not directly bind tubulin; instead, it functions exclusively in protein-protein interactions within the complex (taschner2016intraflagellartransportproteins pages 1-2, taschner2016intraflagellartransportproteins pages 8-9).
IFT38 and IFT57 form a stable heterodimer through their coiled-coil domains. This IFT57/38 module serves as a central architectural connector within IFT-B2, analogous to the role of IFT52 in organizing IFT-B1 (taschner2016intraflagellartransportproteins pages 2-3, taschner2016intraflagellartransportproteins pages 10-12). Furthermore, the IFT57/38 heterodimer also links IFT-B2 to IFT-B1 through interactions with IFT88 and the N-terminal domain of IFT52 (IFT52N), thus forming a critical bridge for IFT-B holocomplex assembly (tasaki2025assemblyandmother pages 1-5, taschner2016intraflagellartransportproteins pages 10-12, taschner2016intraflagellartransportproteins pages 8-9). This tetramer (IFT38/IFT57/IFT52/IFT88) has also been identified as a binding site for heterotrimeric kinesin-II, the anterograde motor (tasaki2025assemblyandmother pages 1-5).
The following table summarizes the molecular interactions of IFT38/DYF-3:
| Domain/Region | Interacting Partner | Interaction Type | Functional Consequence | Evidence Source |
|---|---|---|---|---|
| N-terminal calponin homology (CH) domain of IFT38/DYF-3 | IFT80 | Direct protein-protein interaction; CH domain of IFT38 binds IFT80 | Anchors IFT38 within the IFT-B2/peripheral IFT-B subcomplex; supports IFT-B2 architecture rather than tubulin binding by IFT38 itself (taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 1-2, taschner2016intraflagellartransportproteins pages 5-5) | Taschner et al. 2016 (taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 1-2, taschner2016intraflagellartransportproteins pages 5-5) |
| C-terminal coiled-coil region of IFT38/DYF-3 | IFT57 | Stable heterodimer/coiled-coil association | Forms the IFT57/38 module, a core architectural unit of IFT-B2 that links to additional IFT-B2 components and helps organize complex assembly (taschner2016intraflagellartransportproteins pages 2-3, taschner2016intraflagellartransportproteins pages 10-12, taschner2016intraflagellartransportproteins pages 5-5) | Taschner et al. 2016 (taschner2016intraflagellartransportproteins pages 2-3, taschner2016intraflagellartransportproteins pages 10-12, taschner2016intraflagellartransportproteins pages 5-5) |
| IFT57/38 heterodimer (with IFT38 as one subunit) | IFT172, IFT80, IFT54/20 | Higher-order subcomplex assembly within IFT-B2 | Builds the stable six-subunit IFT-B2 complex (IFT172/80/57/54/38/20), which is required for ciliogenesis and ciliary transport complex integrity (taschner2016intraflagellartransportproteins pages 1-2, taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 2-3, taschner2016intraflagellartransportproteins pages 8-9) | Taschner et al. 2016 (taschner2016intraflagellartransportproteins pages 1-2, taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 2-3, taschner2016intraflagellartransportproteins pages 8-9) |
| IFT57/38 module containing IFT38/DYF-3 | IFT88 and N-terminus of IFT52 (IFT52N) | Bridging interaction between IFT-B2 and IFT-B1 | Connects peripheral IFT-B2 to core IFT-B1, enabling holocomplex formation and anterograde IFT train assembly (tasaki2025assemblyandmother pages 1-5, taschner2016intraflagellartransportproteins pages 10-12, taschner2016intraflagellartransportproteins pages 8-9) | Taschner et al. 2016; Tasaki et al. 2025 (tasaki2025assemblyandmother pages 1-5, taschner2016intraflagellartransportproteins pages 10-12, taschner2016intraflagellartransportproteins pages 8-9) |
| IFT38/DYF-3 as an IFT-B2 subunit at basal body/mother centriole | IFT54, IFT52, IFT88-dependent assembly machinery | Subcomplex recruitment/localization dependency | Recruitment of IFT38 to the mother centriole/basal body depends on IFT54 and IFT-B1b components, indicating a role in pre-ciliary IFT-B assembly before ciliogenesis (tasaki2025assemblyandmother pages 5-10, tasaki2025assemblyandmother pages 1-5) | Tasaki et al. 2025 (tasaki2025assemblyandmother pages 5-10, tasaki2025assemblyandmother pages 1-5) |
| IFT38/CLUAP1 | VCP/UBXD3 | UBXD3 binds IFT38/CLUAP1 and directs VCP/UBXD3 motility with IFT | Implicated in assembly/remodeling of IFT trains at the ciliary base and tip; loss of VCP/UBXD3 disrupts bidirectional IFT and train integrity (tran2016anageof pages 5-7) | Tran & Lechtreck 2016 conference report summarizing primary data (tran2016anageof pages 5-7) |
| CLUAP1/IFT38 interactome (non-IFT-associated fraction) | Ephrin-B1 | Proteomic interaction | Suggests a role outside canonical IFT in cytoskeletal arrangement and cell architecture (beyer2018crisprcas9mediatedgenomicediting pages 1-5, beyer2018crisprcas9mediatedgenomicediting pages 13-17) | Beyer et al. 2018 (beyer2018crisprcas9mediatedgenomicediting pages 1-5, beyer2018crisprcas9mediatedgenomicediting pages 13-17) |
| CLUAP1/IFT38 interactome (non-IFT-associated fraction) | TRIP6 | Proteomic interaction | Links CLUAP1 to actin remodeling and cell migration-related pathways; consistent with actin phenotype in CLUAP1-knockout cells (beyer2018crisprcas9mediatedgenomicediting pages 1-5, beyer2018crisprcas9mediatedgenomicediting pages 17-20, beyer2018crisprcas9mediatedgenomicediting pages 13-17) | Beyer et al. 2018 (beyer2018crisprcas9mediatedgenomicediting pages 1-5, beyer2018crisprcas9mediatedgenomicediting pages 17-20, beyer2018crisprcas9mediatedgenomicediting pages 13-17) |
| CLUAP1/IFT38 interactome (non-IFT-associated fraction) | PDGFA, CCDC6, CEP55, BBS7 | Proteomic interaction network | Expands CLUAP1 functional landscape to ciliogenesis-associated signaling, BBSome-linked pathways, and possible cancer/cell-cycle related processes (beyer2018crisprcas9mediatedgenomicediting pages 25-30, beyer2018crisprcas9mediatedgenomicediting pages 1-5) | Beyer et al. 2018 (beyer2018crisprcas9mediatedgenomicediting pages 25-30, beyer2018crisprcas9mediatedgenomicediting pages 1-5) |
| Worm DYF-3 protein in sensory cilia (orthologous structural role inferred from IFT38) | IFT-B complex in ciliated sensory neurons | Conserved orthologous complex membership | Explains why dyf-3 mutants show severe dye-filling defects and abnormal ciliary protein accumulation in amphid/phasmid neurons, consistent with defective IFT-B-mediated cilium assembly/function (sun2025multipleregulatorsconstrain pages 4-6, efimenko2006caenorhabditiselegansdyf2an pages 1-2) | Sun et al. 2025; Efimenko et al. 2006 (sun2025multipleregulatorsconstrain pages 4-6, efimenko2006caenorhabditiselegansdyf2an pages 1-2) |
Table: This table summarizes the domain-level interactions and higher-order structural organization of IFT38/DYF-3 within the IFT-B complex, along with selected non-IFT partners. It is useful for linking worm DYF-3 function to conserved mechanistic data from vertebrate CLUAP1/IFT38 studies.
In C. elegans, DYF-3 is expressed in ciliated sensory neurons (CSNs), including the amphid neurons in the head and phasmid neurons in the tail (efimenko2006caenorhabditiselegansdyf2an pages 2-3, sun2025multipleregulatorsconstrain pages 4-6). Expression of dyf-3 is regulated by the RFX-type transcription factor DAF-19, which binds to an X-box motif (GTTTCTATGGGAAC) in the dyf-3 promoter, consistent with its classification as a ciliary gene (chu2012finetuningof pages 1-2, efimenko2006caenorhabditiselegansdyf2an pages 2-3, warrington2018computationalandmolecular pages 106-108). DYF-3 has been noted to show expression in only a subset of CSNs, suggesting potential specializations during ciliary development (efimenko2006caenorhabditiselegansdyf2an pages 8-9).
In mammalian cells, CLUAP1/IFT38 localizes throughout the ciliary axoneme and is widely expressed in ciliated tissues, including lung bronchioles and brain ependymal cells (pasek2012mammalianclusterinassociated pages 4-6, pasek2012mammalianclusterinassociated pages 9-9). Studies using knockout cell lines demonstrate that IFT38 is recruited to the mother centriole/basal body prior to ciliogenesis. This basal body recruitment requires IFT54 (another IFT-B2 subunit) and the IFT-B1b subunits IFT52 and IFT88, but is independent of IFT-B1a subunits IFT74 and IFT81 (tasaki2025assemblyandmother pages 5-10). The protein thus occupies multiple ciliary compartments: the basal body (where IFT trains are assembled), along the ciliary axoneme during transport, and the ciliary tip (where trains are remodeled for retrograde transport).
Loss-of-function mutations in dyf-3 produce severe ciliary defects in C. elegans:
Dye-filling defects: The dyf-3(ju1706) allele, which carries a G-to-A transition at the 5′ splice donor site of the exon-intron 3 junction (resulting in out-of-frame splicing after Asp182), and the independent allele dyf-3(m185) both show complete (0%) dye-filling defects in amphid and phasmid sensory neurons, indicating severely compromised ciliary structure (sun2025multipleregulatorsconstrain pages 4-6).
Ciliary protein misaccumulation: dyf-3 mutants exhibit abnormal accumulation of GFP::DLK-1 (a MAP3K) in the cilia region, with intensity comparable to other strong IFT loss-of-function mutations. This demonstrates that DYF-3 participates in IFT-dependent feedback regulation of protein abundance in ciliated sensory neurons (sun2025multipleregulatorsconstrain pages 4-6).
Shortened or absent cilia: Like other IFT-B complex mutants, dyf-3 mutants show drastic reductions in cilia length (efimenko2006caenorhabditiselegansdyf2an pages 1-2).
Anthelmintic resistance: The dyf-3(m185) mutant is associated with ivermectin resistance, consistent with the broader finding that mutations disrupting amphid cilia and IFT function impair avermectin drug uptake through sensory neurons (brinzer2021theuptakeof pages 14-17).
The function of DYF-3/CLUAP1/IFT38 in ciliogenesis is deeply conserved across metazoa. The following table provides a cross-species comparison:
| Organism | Gene Name | Mutant Phenotypes | Key Findings | References |
|---|---|---|---|---|
| Caenorhabditis elegans | dyf-3 (UniProt Q6I6D4; CLUAP1/IFT38 ortholog) | Fully penetrant dye-filling defects in amphid and phasmid neurons (0% dye fill reported for dyf-3 alleles), shortened/severely defective sensory cilia, abnormal accumulation of GFP::DLK-1 in ciliary regions, ivermectin resistance associated with amphid/cilia dysfunction (sun2025multipleregulatorsconstrain pages 4-6, brinzer2021theuptakeof pages 14-17, efimenko2006caenorhabditiselegansdyf2an pages 1-2) | dyf-3 encodes a conserved IFT-B complex component required for sensory cilium development and intraflagellar transport; it is regulated as a ciliary gene by DAF-19/RFX via an X-box motif and functions in ciliated sensory neurons (sun2025multipleregulatorsconstrain pages 4-6, efimenko2006caenorhabditiselegansdyf2an pages 2-3, efimenko2006caenorhabditiselegansdyf2an pages 8-9, warrington2018computationalandmolecular pages 106-108) | Sun et al., 2025, G3, https://doi.org/10.1093/g3journal/jkaf004; Efimenko et al., 2006, Mol Biol Cell, https://doi.org/10.1091/mbc.e06-04-0260; Brinzer et al., 2021, bioRxiv, https://doi.org/10.1101/2021.10.22.465401 (sun2025multipleregulatorsconstrain pages 4-6, brinzer2021theuptakeof pages 14-17, efimenko2006caenorhabditiselegansdyf2an pages 2-3, warrington2018computationalandmolecular pages 106-108) |
| Zebrafish | qilin | Cilia degeneration/loss in pronephric duct, cystogenesis/polycystic kidney-like phenotype; morpholino knockdown produces more severe early cilia loss than some genetic mutants, consistent with maternal contribution masking early phenotypes (pasek2012mammalianclusterinassociated pages 6-9, pasek2012mammalianclusterinassociated pages 1-2, pasek2012mammalianclusterinassociated pages 9-9) | qilin is the zebrafish ortholog of dyf-3/CLUAP1 and is required for cilia assembly and maintenance; zebrafish data support an evolutionarily conserved role in ciliogenesis and renal cilia integrity (pasek2012mammalianclusterinassociated pages 6-9, pasek2012mammalianclusterinassociated pages 1-2, pasek2012mammalianclusterinassociated pages 4-6) | Pasek et al., 2012, Cilia, https://doi.org/10.1186/2046-2530-1-20 (summarizing prior zebrafish work) (pasek2012mammalianclusterinassociated pages 6-9, pasek2012mammalianclusterinassociated pages 1-2, pasek2012mammalianclusterinassociated pages 4-6) |
| Mouse | Cluap1 | Mid-gestation embryonic lethality; failure of embryonic turning; enlarged pericardial sac; neural tube defects/kinks; complete loss of primary cilia in examined tissues; repressed Sonic hedgehog signaling with reduced Ptch1 and Gli1 expression (pasek2012mammalianclusterinassociated pages 4-6, pasek2012mammalianclusterinassociated pages 1-2, pasek2012mammalianclusterinassociated pages 6-9, bangs2017primaryciliaand pages 4-6) | Cluap1 localizes to primary cilia/axoneme and is essential for ciliogenesis in vivo; mammalian loss causes severe developmental defects attributable to absent cilia and impaired Hedgehog signaling, establishing conserved IFT-B function (pasek2012mammalianclusterinassociated pages 4-6, pasek2012mammalianclusterinassociated pages 1-2, pasek2012mammalianclusterinassociated pages 6-9, pasek2012mammalianclusterinassociated pages 9-9) | Pasek et al., 2012, Cilia, https://doi.org/10.1186/2046-2530-1-20; Bangs & Anderson, 2017, Cold Spring Harb Perspect Biol, https://doi.org/10.1101/cshperspect.a028175 (pasek2012mammalianclusterinassociated pages 4-6, pasek2012mammalianclusterinassociated pages 1-2, pasek2012mammalianclusterinassociated pages 6-9, bangs2017primaryciliaand pages 4-6) |
| Human / human cell models | CLUAP1 / IFT38 | In CRISPR-edited hTERT-RPE1 cells, CLUAP1 knockout causes loss of cilia, increased filamentous actin, and impaired cell migration; disease-association resources link IFT38 to Joubert syndrome, Leber congenital amaurosis, skeletal abnormalities, obesity disorder, and type 2 diabetes mellitus (beyer2018crisprcas9mediatedgenomicediting pages 25-30, beyer2018crisprcas9mediatedgenomicediting pages 1-5, beyer2018crisprcas9mediatedgenomicediting pages 17-20, OpenTargets Search: -CLUAP1) | Human CLUAP1/IFT38 is an IFT-B2/peripheral IFT-B subunit with a calponin homology domain that binds IFT80 and forms a heterodimer with IFT57; it contributes structurally to IFT-B assembly and ciliogenesis, and may have separable roles in actin organization/cell migration (taschner2016intraflagellartransportproteins pages 1-2, taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 2-3, taschner2016intraflagellartransportproteins pages 10-12, beyer2018crisprcas9mediatedgenomicediting pages 25-30, beyer2018crisprcas9mediatedgenomicediting pages 1-5) | Taschner et al., 2016, EMBO J, https://doi.org/10.15252/embj.201593164; Beyer et al., 2018, Mol Cell Proteomics, https://doi.org/10.1074/mcp.ra117.000487; Open Targets Platform association summary (OpenTargets Search: -CLUAP1, taschner2016intraflagellartransportproteins pages 1-2, taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 10-12, beyer2018crisprcas9mediatedgenomicediting pages 25-30, beyer2018crisprcas9mediatedgenomicediting pages 1-5) |
Table: This table compares the DYF-3/CLUAP1/IFT38 ortholog across worms, zebrafish, mouse, and human systems, summarizing mutation phenotypes, conserved biological roles, and representative references. It is useful for quickly linking the C. elegans gene to broader cilia biology and disease relevance.
In zebrafish, loss-of-function mutations in qilin (the DYF-3 ortholog) result in cilia degeneration in the pronephric duct and cystogenesis, producing a polycystic kidney disease-like phenotype (pasek2012mammalianclusterinassociated pages 6-9, pasek2012mammalianclusterinassociated pages 1-2). Initial studies suggested that qilin genetic mutants could still assemble cilia, but subsequent morpholino knockdown experiments revealed a more severe cilia-loss phenotype, likely because maternal mRNA contribution in genetic mutants partially rescued early ciliogenesis (pasek2012mammalianclusterinassociated pages 6-9). These data implicate Qilin/CLUAP1 in both cilia assembly and cilia maintenance.
Cluap1 knockout mice die during mid-gestation (between E10.5 and E18.5) with severe developmental abnormalities including failure of embryonic turning, enlarged pericardial sacs, and neural tube defects (pasek2012mammalianclusterinassociated pages 4-6, pasek2012mammalianclusterinassociated pages 1-2). Critically, Cluap1 KO embryos completely lack primary cilia in examined tissues, as demonstrated by the absence of acetylated α-tubulin and Arl13b staining in neural tubes and lateral plate mesenchyme (pasek2012mammalianclusterinassociated pages 4-6, pasek2012mammalianclusterinassociated pages 6-9). The Cluap1 protein localizes throughout the ciliary axoneme and is widely expressed in tissues including bronchioles, ependymal cells, and cells bearing single primary cilia (pasek2012mammalianclusterinassociated pages 4-6).
CRISPR/Cas9-mediated knockout of CLUAP1 in human hTERT-RPE1 cells results in complete absence of cilia and reveals an additional phenotype: increased filamentous actin accumulation and impaired cell migration (beyer2018crisprcas9mediatedgenomicediting pages 25-30, beyer2018crisprcas9mediatedgenomicediting pages 13-17). Rescue experiments showed that CLUAP1 isoform 1 (which binds the IFT-B complex) can restore cilia assembly but does not rescue actin organization, suggesting these are mechanistically separable functions (beyer2018crisprcas9mediatedgenomicediting pages 25-30).
The most well-characterized signaling role of CLUAP1/IFT38 relates to the Sonic hedgehog (Shh) pathway, which in mammals is critically dependent on primary cilia for signal transduction. Cluap1 KO mouse embryos show a repressed Shh signaling pathway: expression of the pathway target genes Patched-1 and Gli1 is reduced to 53.3% and 20.8% of wild-type levels, respectively (pasek2012mammalianclusterinassociated pages 6-9). These embryos lack a properly defined Shh-positive floor plate and show abnormal neural tube patterning (pasek2012mammalianclusterinassociated pages 6-9, bangs2017primaryciliaand pages 4-6). These defects are a direct consequence of absent cilia, as the Shh pathway in mammals requires the cilium as a signaling platform for receptor trafficking (Smoothened accumulation, Gli processing). The phenotype of Cluap1 KO embryos—midgestation lethality and abnormal neural patterning—is consistent with that of other IFT-B mutants (bangs2017primaryciliaand pages 4-6).
C. elegans lacks a canonical Hedgehog signaling pathway, so this specific signaling role is not directly relevant to DYF-3 function in worms. However, the underlying principle—that DYF-3/CLUAP1 is required for cilia-dependent signaling—is conserved, as C. elegans sensory cilia are essential for chemosensation, osmosensation, and other environmental signaling processes.
IFT38/CLUAP1 is also implicated in the regulation of IFT train dynamics. The AAA-ATPase VCP and its cofactor UBXD3 bind directly to IFT38/CLUAP1, which directs VCP/UBXD3 motility through the cilium (tran2016anageof pages 5-7). These proteins function in assembling IFT-A, IFT-B, and BBSome subunits into IFT trains at the ciliary base and in remodeling IFT trains at the ciliary tip for retrograde transport. Loss of functional VCP/UBXD3 disrupts bidirectional IFT train integrity, resulting in uncoupled trafficking of IFT-A and IFT-B particles (tran2016anageof pages 5-7).
Proteomic analysis of endogenously tagged CLUAP1 identified novel interacting partners beyond the IFT-B complex, including Ephrin-B1, TRIP6, Fascin, and TBCD, all of which are involved in cytoskeletal arrangement and protein transport (beyer2018crisprcas9mediatedgenomicediting pages 1-5, beyer2018crisprcas9mediatedgenomicediting pages 17-20, beyer2018crisprcas9mediatedgenomicediting pages 13-17). CLUAP1 knockout cells display altered actin filament organization with more uniformly oriented stress fibers and significantly reduced cell migration (~30–33% gap closure versus ~52% in controls) (beyer2018crisprcas9mediatedgenomicediting pages 13-17). Additional interactions with PDGFA and CCDC6 link CLUAP1 to ciliogenesis-associated signaling and cancer-related cell cycle regulation (beyer2018crisprcas9mediatedgenomicediting pages 1-5). CLUAP1 expression is also reported to be upregulated in colon cancer in a cell-cycle-dependent manner (beyer2018crisprcas9mediatedgenomicediting pages 1-5).
The human ortholog IFT38/CLUAP1 is associated with several ciliopathy-spectrum disorders according to the OpenTargets platform. The strongest association is with Leber congenital amaurosis (association score 0.46), followed by skeletal abnormalities (0.35), obesity disorder (0.33), Joubert syndrome (0.33), and type 2 diabetes mellitus (0.29) (OpenTargets Search: -CLUAP1). These associations reflect the broad role of cilia and IFT in diverse developmental and homeostatic processes. The connection to Joubert syndrome is particularly relevant given that Joubert syndrome is a prototypical ciliopathy affecting neural development.
DYF-3 in C. elegans is an evolutionarily conserved structural protein that functions as a component of the IFT-B2 peripheral subcomplex of the intraflagellar transport machinery. Its primary role is not enzymatic or transport-related in the classical sense; rather, it serves as a protein-protein interaction scaffold that organizes the IFT-B2 subcomplex through its CH domain (binding IFT80) and coiled-coil domain (heterodimerizing with IFT57), and bridges IFT-B2 to IFT-B1 via IFT88/IFT52N interactions (taschner2016intraflagellartransportproteins pages 1-2, tasaki2025assemblyandmother pages 1-5, taschner2016intraflagellartransportproteins pages 3-4, taschner2016intraflagellartransportproteins pages 10-12). This structural role is essential for the assembly and function of IFT trains that transport ciliary building materials and signaling molecules bidirectionally along the ciliary axoneme.
In C. elegans, DYF-3 functions specifically in ciliated sensory neurons (amphid and phasmid), where it is required for normal cilia structure, dye-filling capacity, and regulation of protein abundance within the cilia compartment (sun2025multipleregulatorsconstrain pages 4-6, efimenko2006caenorhabditiselegansdyf2an pages 8-9). Loss of DYF-3 results in severe ciliary structural defects, complete inability to take up fluorescent dyes, and resistance to avermectin anthelmintics (brinzer2021theuptakeof pages 14-17). The conserved functions of the CLUAP1/IFT38 family in ciliogenesis and ciliary signaling—including Shh pathway regulation in vertebrates—underscore the critical importance of this protein in development and disease (pasek2012mammalianclusterinassociated pages 1-2, pasek2012mammalianclusterinassociated pages 6-9, bangs2017primaryciliaand pages 4-6).
References
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