CPLANE1 (JBTS17, formerly C5orf42) supports formation of cilia. Its conserved cellular role is clearer than its molecular activity. In the 2015 study, serum-starved fibroblasts from a human patient carrying compound-heterozygous JBTS17 variants failed to form normal cilia. Direct target immunolocalization was performed in mouse cells: Jbts17 staining lay distal to γ-tubulin, overlapped NPHP1 and decreased after siRNA. The Figure 5 caption and Methods distinguish those experiments from the human fibroblast assay. The authors report: “Immunostaining showed JBTS17 is localized in the cilia transition zone.” PMID:25877302(https://pmc.ncbi.nlm.nih.gov/articles/PMC4476446/)
The 2016 study places Xenopus Jbts17 in a ring at the ciliary base and identifies a recruitment hierarchy. Jbts17 depletion reduces recruitment of selected CPLANE proteins and peripheral IFT-A subunits, while the IFT-A core and tested IFT-B recruitment behave differently. Fuz is an exception to a simple all-subunit hierarchy. Wild-type and disease-associated truncation rescue experiments strengthen the functional interpretation. The Online Methods specify FLAG-Jbts17 residues 907–1569 and GFP-tagged Intu, Fuz and Wdpcp in the wheat-germ pull-down assay; that construct is distinct from the full-length Xenopus imaging/rescue protein. Pairwise binding and recruitment dependence leave open whether CPLANE1 bridges partners, stabilizes assembly or affects delivery. The authors observed that “Jbts17 localized robustly around basal bodies”; the recruitment mechanism remains unresolved. PMID:27158779, target Results, Discussion and Online Methods
The 2025 published study adds Xenopus Jbts17 basal-body docking experiments: depletion causes a defect rescued by wild-type Jbts17-GFP but not the Arg1569* truncation. Its human transition-zone experiments concern RSG1, and the mouse experiments concern Fuz and Intu. Those results support the CPLANE network without making them direct human CPLANE1 localization or enzyme assays. The subsequent correction concerns author metadata. PMID:40593758, Results subsection “RSG1 and JBTS17 variants disrupt basal body docking”
The functional synthesis therefore retains one cilium-assembly unit with basal-body and transition-zone locations and an explicit molecular-function gap. A specific adaptor, scaffold, GEF, transporter or IFT-particle molecular activity is not established by these experiments. Basal-body and transition-zone locations describe complementary experimental contexts, not a claim that both human products were tested at both locations.
The 2022 study combines human family genetics with mouse NIH/3T3 depletion experiments. Ciliation was reduced from 71.67% to 58.61%, with migration and Hedgehog-pathway readouts also altered. Ciliary tubulin staining is not direct CPLANE1 localization. Inconsistent narrative wording about Ptch1 is not used to assign a directional mechanism. PMID:35582950, Results/Figure 2 and cell-culture Methods
The 2019 original abstract and Figures 1–5 caption text describe endogenous human HeLa kinetochore localization and JBTS17 immunoprecipitation, alongside tagged full-length and JCD constructs, human RPE1 ciliation experiments and mouse model contexts. These are positive extraciliary observations. Full Methods/Results and precise fragment boundaries were not available, so these observations do not establish a defined bridging or motor activity. PMID:31004438, original abstract and figure-caption preview; publisher DOI.
The official displayed human product Q9H799-1 has 3,197 residues. The named second product uses accession Q9H799-5 and has 2,933 residues. Its sequence is reproduced exactly by the four official VSP edits. Sequence reconstruction establishes identity, not equivalent localization or activity. The published Xenopus constructs are not assigned these human product identifiers. The reviewed human record predicts two transmembrane segments; membrane insertion and topology remain experimentally unresolved in the sources considered here. Broad membrane association is retained as a non-core prediction. UniProt Q9H799
The current PANTHER v19 tree places the exact displayed human sequence at leaf PTN002494735 below ancestral node PTN002684007. Literal IBD records at that node support cilium assembly and transition-zone localization. Mouse Q8CE72 supplies experimental localization and assembly evidence; frog A0A1L8I2G6 and human Q9H799 add assembly evidence. The target appearing among descendant evidence is valid experimental grounding, not circularity. Current records support the placement without recreating every historical curator decision.
Exact source identities, product edits, primary access boundaries, term definitions and the current tree/IBD/donor reconstruction are recorded in the source evidence index.
The broad cilium source now refines to both ciliary transition zone and ciliary basal body. The transition-zone replacement corroborates the existing accepted IBA; basal body is the additional supported location and agrees with the unchanged core. The two sites have distinct experimental grounding: mouse Jbts17 immunostaining, NPHP1 colocalization and siRNA antibody validation support transition-zone localization, whereas Toriyama et al., basal-body imaging in Figure 2g–h and construct Methods show full-length Xenopus GFP-Jbts17 in a ring around centrin4-marked basal bodies. The human patient-fibroblast result establishes defective ciliogenesis rather than directly measuring these localization sites. Neither replacement is an exclusive localization claim.
The 2016 Online Methods distinguish the full-length Xenopus localization constructs from the Jbts17 907–1569 fragment used in wheat-germ pull-down experiments. Association with the INTU–FUZ–WDPCP module remains positive, but its composition, stoichiometry and molecular recruitment mechanism should be resolved before assigning a particular complex or scaffold activity. The existing molecular-activity gap is unchanged. The saved ontology search returned no hits for the literal query CPLANE; that limited result does not establish that no relevant ontology term exists. No new biological annotation or quotation is added.