CFAP410 (C21ORF2/LRRC76) is a leucine-rich-repeat protein associated with the serine/threonine kinase NEK1. It is found at ciliary basal bodies and photoreceptor connecting cilia, with an additional cytoplasmic pool. Its C-terminal domain forms a tetrameric helical bundle in vitro. Loss of CFAP410 or disease-associated variants disrupt primary-cilium formation and function in human cellular models, including motor neurons. Depletion also reduces homologous-recombination reporter repair, although the repair-specific molecular contribution of the CFAP410βNEK1 complex remains unresolved. Biallelic variants cause retinal ciliopathies with variable skeletal involvement, and some variants are associated with amyotrophic lateral sclerosis.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0001750 photoreceptor outer segment | IDA PMID:27548899 Identification of Novel Mutations in the LRR-Cap Domain of C... | UNDECIDED | Summary: The precise outer-segment assignment remains unresolved. Reason: The original PMID:27548899 abstract establishes adult retinal photoreceptor-cilium localization, but does not resolve the outer segment defined by GO:0001750. Renewed publisher/DOI access attempts did not recover its full localization images and Methods. In contrast, full PMID:26974433 Figure 6EβQ places human NM_004928.2βEGFP in mouse photoreceptor connecting cilia, not surrounding outer-segment structures. That heterologous construct/context does not refute the original observation. Preserve the IDA or SL-0458 mapping as unresolved at this compartment precision; the separately supported connecting-cilium term is not interchangeable with it. Supporting Evidence: PMID:27548899 the protein localized to the photoreceptor cilia file:human/CFAP410/CFAP410-source-evidence.json |
| GO:0001750 photoreceptor outer segment | IEA GO_REF:0000044 | UNDECIDED | Summary: The precise outer-segment assignment remains unresolved. Reason: The original PMID:27548899 abstract establishes adult retinal photoreceptor-cilium localization, but does not resolve the outer segment defined by GO:0001750. Renewed publisher/DOI access attempts did not recover its full localization images and Methods. In contrast, full PMID:26974433 Figure 6EβQ places human NM_004928.2βEGFP in mouse photoreceptor connecting cilia, not surrounding outer-segment structures. That heterologous construct/context does not refute the original observation. Preserve the IDA or SL-0458 mapping as unresolved at this compartment precision; the separately supported connecting-cilium term is not interchangeable with it. |
| GO:0005515 protein binding | IPI PMID:25416956 A proteome-scale map of the human interactome network. | KEEP AS NON CORE | Summary: The exact human CFAP410βATOX1 screen interaction is supported. Reason: The source-linked IntAct records EBI-10179265, EBI-10337397 and EBI-10498856 identify human O43822 and O00244 in pooling, array and validated yeast two-hybrid records of PMID:25416956. These are assay stages from one publication, not independent biological replications. Retain supported generic binding under the explicit ClinGen project instruction. Neither this interaction nor ATOX1 identity establishes copper transfer, copper binding or a specific adaptor activity of CFAP410. Literal pair, method, host, taxon and negative-flag fields are preserved in the source artifact. |
| GO:0005515 protein binding | IPI PMID:26167768 An siRNA-based functional genomics screen for theΒ identifica... | MODIFY | Summary: The NEK1 association supports protein serine/threonine kinase binding. Reason: PMID:26167768 tests tagged human proteins in HEK293T cells and reports mutation-sensitive NEK1 association; its endogenous retinal co-IP uses bovine tissue. The partner is a serine/threonine kinase, so GO:0120283 is more informative than generic binding. Independent endogenous human complex characterization in PMID:37188479 corroborates the association. Co-IP and mutation-sensitive complex formation support this binding class without assigning intrinsic kinase activity, kinase activation, a purified binary interface or direct DNA-repair work to CFAP410. Proposed replacements: protein serine/threonine kinase binding Supporting Evidence: PMID:26167768 mutations in C21orf2 abolished the interaction with NEK1 |
| GO:0005515 protein binding | IPI PMID:26290490 The NEK1 interactor, C21ORF2, is required for efficient DNA ... | MODIFY | Summary: The NEK1 association supports protein serine/threonine kinase binding. Reason: PMID:26290490 reports human-cell CFAP410βNEK1 co-immunoprecipitation; its repair phenotypes do not identify a repair-specific molecular step performed by CFAP410. The partner is a serine/threonine kinase, so GO:0120283 is more informative than generic binding. Independent endogenous human complex characterization in PMID:37188479 corroborates the association. Co-IP and mutation-sensitive complex formation support this binding class without assigning intrinsic kinase activity, kinase activation, a purified binary interface or direct DNA-repair work to CFAP410. Proposed replacements: protein serine/threonine kinase binding |
| GO:0005737 cytoplasm | IDA PMID:21834987 Identification and characterization of a set of conserved an... | ACCEPT | Summary: True: entailed by cytosol and mitochondrion, kept in this review. Reason: The claim is true: cytosol and mitochondrion, kept in this review, entail this term. Other rows for this term are ACCEPTed. This row's reference does not establish it; that is recorded in source_defects, not grounds for REMOVE, which judges the claim. |
| GO:0005737 cytoplasm | IDA PMID:26290490 The NEK1 interactor, C21ORF2, is required for efficient DNA ... | ACCEPT | Summary: CFAP410 has an experimentally observed cytoplasmic pool. Reason: PMID:26290490 directly shows HA-tagged human CFAP410 in the cytoplasm of HeLa cells, without detectable damage-induced nuclear recruitment or foci. This supports the original broad compartment assertion and independently corroborates the electronic SL-0086 mapping. It does not imply direct homologous-recombination participation or repair-site localization. The unsupported PMID:21834987 source attribution is assessed separately. Supporting Evidence: PMID:26290490 C21ORF2 was observed to be localized to the cytoplasm |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | ACCEPT | Summary: CFAP410 has an experimentally observed cytoplasmic pool. Reason: PMID:26290490 directly shows HA-tagged human CFAP410 in the cytoplasm of HeLa cells, without detectable damage-induced nuclear recruitment or foci. This supports the original broad compartment assertion and independently corroborates the electronic SL-0086 mapping. It does not imply direct homologous-recombination participation or repair-site localization. The unsupported PMID:21834987 source attribution is assessed separately. Supporting Evidence: |
| GO:0005739 mitochondrion | IDA PMID:9325172 Immunochemical characterization of a novel mitochondrially l... | KEEP AS NON CORE | Summary: The early human-cell mitochondrial localization is retained at its stated assay scope. Reason: The original PMID:9325172 abstract explicitly describes antibody staining and mitochondrial-dye colocalization in human cells. Full article access remains unavailable, so no additional antibody validation or isoform assignment is inferred. This positive historical observation supports retention as peripheral localization. Human NM_004928.2βEGFP in mouse photoreceptors instead has a distribution complementary to a mitochondrial marker (PMID:26974433 Figure 6OβQ); that different context does not disprove the human-cell result. Respiratory phenotypes in variant motor neurons do not by themselves establish mitochondrial residence or catalysis. ORGANELLES batch 2 check (2026-10-24): immunofluorescence with dye co-staining resolves only the organelle, and the abstract itself says the result "suggests" mitochondria; kept as non-core because the full text is unavailable and the curator's observation is not overruled. Supporting Evidence: PMID:9325172 co-staining with a mitochondrial-specific dye suggest the subcellular localization of the protein to mitochondria. |
| GO:0005739 mitochondrion | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: The early human-cell mitochondrial localization is retained at its stated assay scope. Reason: The original PMID:9325172 abstract explicitly describes antibody staining and mitochondrial-dye colocalization in human cells. Full article access remains unavailable, so no additional antibody validation or isoform assignment is inferred. This positive historical observation supports retention as peripheral localization. Human NM_004928.2βEGFP in mouse photoreceptors instead has a distribution complementary to a mitochondrial marker (PMID:26974433 Figure 6OβQ); that different context does not disprove the human-cell result. Respiratory phenotypes in variant motor neurons do not by themselves establish mitochondrial residence or catalysis. Examined as a synthesis row (ORGANELLES batch 2, 2026-10-24): SL-0173 maps the curated line "Mitochondrion {ECO:0000269|PubMed:9325172}", so this row rests on the same 1997 paper as the IDA row and adds no independent line. The organelle claim is weak (one antisera-based study, a complementary distribution in photoreceptors, HPA reporting cytosol), but it is kept consistent with the direct row pending its full text; if that shows no stronger assay, both rows would become MARK_AS_OVER_ANNOTATED. Rule 4 is not met: the only sub-compartment hint is a predicted N-terminal targeting signal mentioned in PMID:26974433, which UniProt does not annotate as a transit peptide, and there is no TM segment or sub-mitochondrial assay. Stays at the root. Supporting Evidence: PMID:26974433 subcellular distribution of the C21orf2-EGFP fusion protein was complementary to that of mitochondria PMID:26974433 a predicted mitochondria localization signal peptide file:human/CFAP410/CFAP410-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion {ECO:0000269|PubMed:9325172}. |
| GO:0005829 cytosol | IDA GO_REF:0000052 | KEEP AS NON CORE | Summary: Human Protein Atlas assays support a cytosolic CFAP410 pool. Reason: The current HPA XML records cytosol in A-431, U-251MG and U2OS assays with HPA030284 and supported ICC/IF reliability; the A-431 image was inspected. PMID:26290490 independently establishes cytoplasmic localization. HPA standard/literature support is not genetic knockout validation, and its Western-blot reliability is uncertain. This is a coarse supporting location alongside the basal-body kinase-binding core, not a new cytosolic activity. |
| GO:0005886 plasma membrane | IDA PMID:21834987 Identification and characterization of a set of conserved an... | REMOVE | Summary: The Bai2011 source does not establish the asserted CFAP410 plasma membrane localization. Reason: The actual full Results, cloning Methods and Figure 8 identify ARC, FAM40A, FAM40B, FMNL3 and ZRANB1 as the GFP localization constructs. CFAP410 instead appears in the siRNA morphology screen; cortical-actin organization is its phenotype, not its localization. The Figure 8 pixels and supplementary captions were inspected again. This preserves the prior source-specific removal on direct examination of the experiments, not absence from an abstract. The 2024 correction concerns duplicated siARC/siZRANB images in Figure 6, not the Figure 8 construct set. Independent cytoplasmic localization remains supported; this decision does not assert that native plasma-membrane association is impossible. Supporting Evidence: PMID:21834987 cDNAs for ARC, FAM40A, FAM40B, FMNL3 and ZRANB1 file:human/CFAP410/CFAP410-source-evidence.json |
| GO:0032391 photoreceptor connecting cilium | IEA GO_REF:0000107 | ACCEPT | Summary: Photoreceptor connecting-cilium localization is supported with the construct species made explicit. Reason: The proximate Q8C6G1 donor is mouse Cfap410 and currently carries an IDA for PMID:26974433. The actual Figure 6 Methods use human CFAP410 coding sequence NM_004928.2 fused to EGFP, delivered by AAV into mouse retina; its connecting-cilium signal therefore also directly informs the human product. This is not an endogenous human-retina assay. PMID:26294103 independently reports human, pig and mouse retinal immunohistochemistry. Preserve the original transfer fields rather than rewriting the curated donor or pretending that the historic Ensembl propagation was fully reconstructed. Supporting Evidence: PMID:26974433 C21orf2 protein is localized at the connecting cilia file:human/CFAP410/CFAP410-source-evidence.json |
| GO:0032391 photoreceptor connecting cilium | ISS GO_REF:0000024 | ACCEPT | Summary: Photoreceptor connecting-cilium localization is supported with the construct species made explicit. Reason: The proximate Q8C6G1 donor is mouse Cfap410 and currently carries an IDA for PMID:26974433. The actual Figure 6 Methods use human CFAP410 coding sequence NM_004928.2 fused to EGFP, delivered by AAV into mouse retina; its connecting-cilium signal therefore also directly informs the human product. This is not an endogenous human-retina assay. PMID:26294103 independently reports human, pig and mouse retinal immunohistochemistry. Preserve the original transfer fields rather than rewriting the curated donor or pretending that the historic Ensembl propagation was fully reconstructed. |
| GO:0036064 ciliary basal body | IDA GO_REF:0000052 | ACCEPT | Summary: HPA basal-body localization has independent target-specific corroboration. Reason: Current HPA XML assigns basal body as an additional location and identifies an ASC52telo assay with basal-body/Golgi signal using HPA030284. Its selected raw image was too dim for an independent basal-body call, so this assessment relies on the literal curated assay record and independent PMID:26167768/37188479 human-cell basal-body experiments. Do not describe the HPA antibody as knockout-validated or use the cell-line staining to infer a new function. |
| GO:0036064 ciliary basal body | IDA PMID:26167768 An siRNA-based functional genomics screen for theΒ identifica... | ACCEPT | Summary: Human CFAP410 localizes to the ciliary basal body. Reason: The full PMID:26167768 study directly localizes CFAP410 to basal bodies in human hTERT-RPE1 and mouse mIMCD3 cells and to the base of the connecting cilium in mouse photoreceptors. The human and mouse observations are distinguished rather than inferred from an undifferentiated mammalian label. Independent human ARPE-19 knockout-controlled localization in PMID:37188479 corroborates the basal-body pool. |
| GO:0036064 ciliary basal body | IDA PMID:26294103 C21orf2 is mutated in recessive early-onset retinal dystroph... | ACCEPT | Summary: The original retinal study explicitly supports basal-body localization. Reason: The authentic PMID:26294103 abstract reports immunohistochemical localization in human, pig and mouse retinas to the daughter basal body, adjacent centriole and connecting cilium. The full paper was not recovered; no uninspected images or antibody controls are claimed. That explicit target-level observation and independent human-cell basal-body evidence support retention of the curator assertion. Supporting Evidence: PMID:26294103 the daughter basal body, the centriole adjacent to the basal body, and the connecting cilium |
| GO:0036064 ciliary basal body | IEA GO_REF:0000120 | ACCEPT | Summary: The combined electronic basal-body assertion is independently supported in human cells. Reason: Preserve the ARBA, mouse Q8C6G1 and Ensembl source fields. Literal current mouse GOA includes experimental basal-body records, while the full human hTERT-RPE1 and ARPE-19 experiments in PMID:26167768 and PMID:37188479 establish the target location independently. Current donor support does not reconstruct every historical rule step, but no target-specific localization conflict is present. |
| GO:0097733 photoreceptor cell cilium | IEA GO_REF:0000120 | ACCEPT | Summary: CFAP410 is localized in photoreceptor ciliary structures. Reason: GO:0097733 encompasses the specialized photoreceptor cilium, including its connecting-cilium transition zone. The human/mammalian retinal immunohistochemistry reported in PMID:26294103 and human-EGFP construct in mouse retina in PMID:26974433 support this broad location. Acceptance does not settle the more precise outer-segment IDA, which remains unresolved. Preserve the original combined ARBA/ortholog source provenance. |
| GO:1905515 non-motile cilium assembly | IMP PMID:37188479 Functional characterization of C21ORF2 association with the ... | NEW | Summary: CFAP410 makes a local nonenzymatic contribution to primary-cilium assembly. Reason: Retain the prior authored proposal on combined participation evidence, not knockout necessity alone. PMID:37188479 identifies an endogenous human NEK1 complex at the ciliary base and shows interaction-sensitive loss/rescue of ciliogenesis; PMID:26167768 independently supports the local complex and mutation-sensitive association. PMID:39703094 adds CFAP410 association with gamma-tubulin/CEP290, mutation-sensitive basal-body clustering and ciliation rescue. Together these support an inferred local assembly-cofactor contribution by CFAP410 itself, while the exact molecular step remains unresolved. No purified binary binding, NEK1 recruitment/activation, IFT cargo transport or a demonstrated scaffold bridge is claimed. The original Figure5 compares each protein with its own knockout and does not establish cross-recruitment. Official assembly ancestry has no overlap with the 19 machine terms; contextual comparator records and the target-free GO-CAM index are documented in the source artifact. The human ARPE-19 and hTERT-RPE1 experiments assess primary cilia, supporting the non-motile specialization; the contextual comparator annotations use parent cilium-assembly/organization terms. This human assertion does not exclude motile-cilium or flagellar roles of orthologs. Supporting Evidence: PMID:37188479 association of NEK1 and C21ORF2 PMID:37188479 show major defects in ciliogenesis file:human/CFAP410/CFAP410-source-evidence.json |
Loading supporting contentβ¦
Download this section (compressed HTML)Q: Which repair-specific work does CFAP410 perform: does its NEK1 association control kinase stability, localization, substrate selection or phosphorylation in homologous recombination, beyond the demonstrated depletion phenotype?
Q: Are reported mitochondrial and plasma-membrane pools isoform-, cell-type- or antibody-dependent, and do endogenous tagging and knockout controls confirm them?
Q: Are IFT and Hedgehog defects primary consequences of CFAP410 loss, or downstream effects of altered cilium assembly and structure?
Experiment: Reconstitute purified human NEK1 and CFAP410, compare wild-type and binding-disrupting variants for physical association, kinase kinetics and substrate phosphorylation, and rescue matched CFAP410-null cells with variants controlled for abundance.
Hypothesis: CFAP410 supports NEK1 function through a separable binding-dependent mechanism.
Type: Biochemical reconstitution and cellular rescue
Experiment: Compare endogenous isoform-aware tags in retinal epithelial cells, motor neurons and B cells, including EBV-transformed B cells. Confirm tagged-protein function and use CFAP410-null controls. Resolve membrane-associated signal from adjacent basal bodies/cilia by three-dimensional imaging with compartment markers, then test membrane association by orthogonal fractionation with plasma-membrane, mitochondrial, ER and cytosolic purity controls. Use extraction conditions that distinguish peripheral association from integral-membrane residence; extracellular surface labeling alone cannot assess a cytosolic peripheral pool.
Hypothesis: Native peripheral plasma-membrane association can be distinguished from basal-body/ciliary localization and may depend on isoform or cell context.
Type: Endogenous tagging, compartment-resolved imaging and controlled fractionation
Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)Loading supporting contentβ¦
Download this section (compressed HTML)