{"gene":"CPLANE2","run_date":"2026-06-09T22:57:19","timeline":{"discoveries":[{"year":2017,"finding":"RSG1 (CPLANE2) localizes to the mother centriole in a process that depends on tau tubulin kinase 2 (TTBK2), the CPLANE complex protein Inturned (INTU), and its own GTPase activity. Mouse embryos lacking RSG1 die at E12.5 with decreased Hedgehog signaling; mutant mother centrioles recruit cilia initiation proteins and dock onto ciliary vesicles, but axonemal microtubules fail to elongate, indicating RSG1 acts at a final maturation step of the mother centriole/ciliary vesicle to allow axonemal extension.","method":"Mouse knockout (loss-of-function), live imaging/immunofluorescence localization, genetic dependency analysis (TTBK2/INTU mutant backgrounds), GTPase activity assays","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO with defined cellular phenotype, multiple orthogonal methods (localization, epistasis, GTPase activity), replicated across genetic contexts","pmids":["29038301"],"is_preprint":false},{"year":2013,"finding":"Rsg1 (CPLANE2) is required for normal axonemal IFT dynamics in multiciliated cells, for cytoplasmic localization of the retrograde IFT-A protein IFT43, and for apical localization of basal bodies. Loss of Rsg1 in Xenopus impairs all three processes, placing RSG1 as a regulator of multiple aspects of ciliogenesis including basal body trafficking and IFT protein localization.","method":"Morpholino-based loss-of-function in Xenopus multiciliated cells, live imaging of IFT dynamics, immunofluorescence localization of IFT43 and basal body markers","journal":"Cilia","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KD with defined cellular phenotypes, multiple readouts in a single lab/study","pmids":["24192041"],"is_preprint":false},{"year":2024,"finding":"A point mutation in the GTP-binding pocket (G1 domain) of RSG1 in the mouse L3P mutant disrupts Sonic hedgehog signaling and cilia initiation. The mutant RSG1 protein and other centrosomal/IFT proteins still localize to the basal body, indicating that RSG1 GTPase activity is not required for basal body maturation but is needed for a downstream step in axonemal elongation.","method":"Forward genetic screen, point mutation mapping, immunofluorescence localization of RSG1 and IFT proteins in mutant vs. wild-type mouse embryos","journal":"Genesis (New York, N.Y. : 2000)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — defined point mutation in GTP-binding domain, multiple localization readouts, single lab","pmids":["38721990"],"is_preprint":false},{"year":2025,"finding":"Affinity purification mass spectrometry (APMS) shows that RSG1 (CPLANE2) binds the CPLANE complex and the transition zone protein FAM92 in a GTP-dependent manner. Disease-associated variants in CPLANE2/RSG1 disrupt two vital steps of ciliogenesis: basal body docking and recruitment of intraflagellar transport proteins. CPLANE is required for normal transition zone architecture.","method":"Affinity purification mass spectrometry (APMS), patient-derived variant analysis, ciliogenesis assays (basal body docking, IFT recruitment), transition zone architecture imaging","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — APMS binding data with GTP-dependency, functional assays with patient variants, multiple orthogonal methods, peer-reviewed publication","pmids":["40593758"],"is_preprint":false},{"year":2024,"finding":"RSG1 (CPLANE2) binds the CPLANE complex and the transition zone protein FAM92 in a GTP-dependent manner (preprint version of the same finding, independently confirming the peer-reviewed result).","method":"Affinity purification mass spectrometry (APMS), GTP-dependency assay, ciliogenesis functional assays","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — APMS with GTP-dependency, single lab, preprint prior to peer-reviewed publication","pmids":["39386566"],"is_preprint":true},{"year":2025,"finding":"Folic acid at moderate levels benefits cilia-based neural tube defects in RSG1 mutant mice. The proposed mechanism is that fortified FA levels reduce basal reactive oxygen species (ROS), which in turn reduces ROS-sensitive GTPase activity required for ciliogenesis, suggesting RSG1 GTPase activity is ROS-sensitive.","method":"Mouse NTD models with Rsg1 mutation, folic acid dosage experiments, ROS measurement, cilia formation assays","journal":"Developmental biology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, proposed ROS-GTPase mechanism not directly validated for RSG1 specifically","pmids":["39755226"],"is_preprint":false},{"year":2020,"finding":"Bioinformatic analysis identifies INTU and FUZ (CPLANE complex partners of RSG1) as novel members of homologous HerMon complexes containing tripled Longin domains, suggesting INTU/FUZ may act as GEFs for Rab GTPases during ciliogenesis, providing structural context for how RSG1 operates within the CPLANE complex.","method":"Evolutionary coevolution-based contact prediction and sequence conservation analysis (computational)","journal":"Bioinformatics (Oxford, England)","confidence":"Low","confidence_rationale":"Tier 4 / Weak — computational prediction only, no direct experimental validation of RSG1 specifically","pmids":["31562761"],"is_preprint":false},{"year":2030,"finding":"In silico three-dimensional structural analysis predicts that a pathogenic FUZ variant alters interactions between FUZ and CPLANE2 (RSG1), potentially disrupting ciliogenesis. This supports a direct physical interaction between FUZ and RSG1 within the CPLANE complex.","method":"In silico 3D structural analysis of variant effect on FUZ–RSG1 interaction","journal":"Clinical genetics","confidence":"Low","confidence_rationale":"Tier 4 / Weak — computational structural prediction only, no direct experimental validation of the FUZ–RSG1 interaction","pmids":["41952398"],"is_preprint":false}],"current_model":"CPLANE2/RSG1 is a small GTPase that localizes to the mother centriole in a TTBK2- and INTU-dependent manner and is required for a final step in cilia initiation—specifically, axonemal microtubule elongation after basal body docking onto ciliary vesicles—through its GTPase activity; it physically binds the CPLANE complex (via INTU/FUZ) and the transition zone protein FAM92 in a GTP-dependent manner, and its loss disrupts basal body docking, IFT protein recruitment, IFT dynamics, and transition zone architecture, causing ciliopathy in humans and mice."},"narrative":{"mechanistic_narrative":"CPLANE2 (RSG1) is a small GTPase that governs a late maturation step of ciliogenesis at the mother centriole, where it is required for axonemal microtubule elongation after the basal body has docked onto ciliary vesicles [PMID:29038301]. It localizes to the mother centriole in a manner dependent on tau tubulin kinase 2 (TTBK2), the CPLANE complex protein Inturned (INTU), and its own GTPase activity, and its loss in mouse embryos produces lethality with diminished Hedgehog signaling despite proper recruitment of cilia initiation proteins and ciliary vesicle docking [PMID:29038301]. A point mutation in the GTP-binding (G1) pocket disrupts Hedgehog signaling and cilia initiation without preventing basal body localization of RSG1 or IFT proteins, establishing that its GTPase activity acts downstream of basal body maturation to drive axonemal extension [PMID:38721990]. CPLANE2 physically associates with the CPLANE complex and the transition zone protein FAM92 in a GTP-dependent manner, and its disease-associated variants disrupt basal body docking, intraflagellar transport protein recruitment, and transition zone architecture, causing ciliopathy in humans [PMID:40593758]. Across multiciliated cells it additionally regulates axonemal IFT dynamics, cytoplasmic localization of the retrograde IFT-A protein IFT43, and apical positioning of basal bodies [PMID:24192041].","teleology":[{"year":2013,"claim":"Established RSG1 as a multi-functional ciliogenesis regulator by showing it is needed for IFT dynamics, IFT43 localization, and basal body trafficking, moving it beyond a single discrete role.","evidence":"Morpholino loss-of-function in Xenopus multiciliated cells with live IFT imaging and marker immunofluorescence","pmids":["24192041"],"confidence":"Medium","gaps":["Did not define the molecular activity linking RSG1 to IFT","Knockdown specificity not orthogonally validated","No direct partner identified"]},{"year":2017,"claim":"Placed RSG1 at a defined point in the ciliogenesis pathway by showing its mother-centriole localization depends on TTBK2, INTU, and GTPase activity, and that its loss blocks axonemal elongation after vesicle docking.","evidence":"Mouse knockout with localization imaging, genetic epistasis in TTBK2/INTU backgrounds, and GTPase activity assays","pmids":["29038301"],"confidence":"High","gaps":["Direct molecular effectors of axonemal elongation not identified","How GTPase cycling is regulated at the centriole unknown","Mechanism connecting RSG1 to Hedgehog signaling not resolved"]},{"year":2024,"claim":"Separated RSG1's structural localization role from its catalytic role by showing a G1-domain point mutation blocks cilia initiation while leaving basal body localization of RSG1 and IFT proteins intact.","evidence":"Forward genetic screen and point mutation mapping with localization imaging in mutant vs wild-type mouse embryos","pmids":["38721990"],"confidence":"Medium","gaps":["GTP-loaded effector engaged during elongation not identified","Single lab, single allele","Does not explain how GTP hydrolysis is coupled to axonemal extension"]},{"year":2025,"claim":"Identified the physical partners of RSG1 and tied human disease variants to specific ciliogenesis failures, defining how RSG1 operates within the CPLANE complex and at the transition zone.","evidence":"Affinity purification mass spectrometry with GTP-dependency, patient-variant functional ciliogenesis assays, and transition zone imaging (peer-reviewed; preceded by a confirming preprint)","pmids":["40593758","39386566"],"confidence":"High","gaps":["Direct vs indirect nature of the FAM92 interaction not fully resolved","Structural basis of GTP-dependent binding undefined","Order of events linking docking, IFT recruitment, and transition zone assembly unclear"]},{"year":2025,"claim":"Proposed that RSG1 GTPase activity is redox-sensitive, offering a mechanistic rationale for folic acid rescue of neural tube defects in mutant mice.","evidence":"Rsg1 mutant mouse NTD models with folic acid dosing, ROS measurement, and cilia formation assays","pmids":["39755226"],"confidence":"Low","gaps":["ROS-sensitivity of RSG1 GTPase activity not directly validated for the protein","Single lab","Mechanism is proposed, not biochemically demonstrated"]},{"year":null,"claim":"The downstream GTP-dependent effector through which RSG1 drives axonemal microtubule elongation, and the structural basis of its CPLANE/FAM92 engagement, remain undefined.","evidence":"","pmids":[],"confidence":"Low","gaps":["No identified effector executing axonemal extension","No experimental structure of the RSG1-CPLANE-FAM92 assembly","Regulator of RSG1 GTP/GDP cycling at the centriole unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003924","term_label":"GTPase activity","supporting_discovery_ids":[0,2]}],"localization":[{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[0,2]},{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[0,1]}],"pathway":[{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[0,3]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0]}],"complexes":["CPLANE complex"],"partners":["INTU","FUZ","FAM92","TTBK2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9BU20","full_name":"Ciliogenesis and planar polarity effector 2","aliases":["REM2- and Rab-like small GTPase 1"],"length_aa":258,"mass_kda":28.5,"function":"Required for efficient primary cilia initiation, regulating a late step in cilia initiation. Plays a role in the final maturation of the mother centriole and ciliary vesicle that allows extension of the ciliary axoneme","subcellular_location":"Cytoplasm, cytoskeleton, cilium basal body; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriole","url":"https://www.uniprot.org/uniprotkb/Q9BU20/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/CPLANE2","classification":"Not Classified","n_dependent_lines":11,"n_total_lines":1208,"dependency_fraction":0.009105960264900662},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/CPLANE2","total_profiled":1310},"omim":[{"mim_id":"620487","title":"CILIOGENESIS AND PLANAR POLARITY EFFECTOR COMPLEX, SUBUNIT 2; CPLANE2","url":"https://www.omim.org/entry/620487"},{"mim_id":"613580","title":"WD REPEAT-CONTAINING PLANAR CELL POLARITY EFFECTOR; WDPCP","url":"https://www.omim.org/entry/613580"},{"mim_id":"610622","title":"FUZZY PLANAR CELL POLARITY PROTEIN; FUZ","url":"https://www.omim.org/entry/610622"},{"mim_id":"610621","title":"INTURNED PLANAR CELL POLARITY PROTEIN; INTU","url":"https://www.omim.org/entry/610621"},{"mim_id":"610501","title":"NEUROBLASTOMA BREAKPOINT FAMILY, MEMBER 1; NBPF1","url":"https://www.omim.org/entry/610501"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Nuclear bodies","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/CPLANE2"},"hgnc":{"alias_symbol":["MGC10731"],"prev_symbol":["C1orf89","RSG1"]},"alphafold":{"accession":"Q9BU20","domains":[{"cath_id":"3.40.50.300","chopping":"16-247","consensus_level":"high","plddt":92.4233,"start":16,"end":247}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BU20","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BU20-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BU20-F1-predicted_aligned_error_v6.png","plddt_mean":90.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CPLANE2","jax_strain_url":"https://www.jax.org/strain/search?query=CPLANE2"},"sequence":{"accession":"Q9BU20","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9BU20.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9BU20/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BU20"}},"corpus_meta":[{"pmid":"14634138","id":"PMC_14634138","title":"Placental cell expression of HLA-G2 isoforms is limited to the invasive trophoblast phenotype.","date":"2003","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/14634138","citation_count":90,"is_preprint":false},{"pmid":"9342332","id":"PMC_9342332","title":"Molding a peptide into an RNA site by in vivo peptide evolution.","date":"1997","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/9342332","citation_count":53,"is_preprint":false},{"pmid":"29038301","id":"PMC_29038301","title":"The small GTPase RSG1 controls a final step in primary cilia initiation.","date":"2017","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/29038301","citation_count":29,"is_preprint":false},{"pmid":"11358697","id":"PMC_11358697","title":"Structural characterization of the complex of the Rev response element RNA with a selected peptide.","date":"2001","source":"Chemistry & biology","url":"https://pubmed.ncbi.nlm.nih.gov/11358697","citation_count":26,"is_preprint":false},{"pmid":"2843369","id":"PMC_2843369","title":"A new family of repetitive, retroposon-like sequences in the genome of the rainbow trout.","date":"1988","source":"European journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/2843369","citation_count":26,"is_preprint":false},{"pmid":"16043495","id":"PMC_16043495","title":"Evolvability of the mode of peptide binding by an RNA.","date":"2005","source":"RNA (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/16043495","citation_count":24,"is_preprint":false},{"pmid":"24192041","id":"PMC_24192041","title":"The Small GTPase Rsg1 is important for the cytoplasmic localization and axonemal dynamics of intraflagellar transport proteins.","date":"2013","source":"Cilia","url":"https://pubmed.ncbi.nlm.nih.gov/24192041","citation_count":19,"is_preprint":false},{"pmid":"35740972","id":"PMC_35740972","title":"CPLANE Complex and Ciliopathies.","date":"2022","source":"Biomolecules","url":"https://pubmed.ncbi.nlm.nih.gov/35740972","citation_count":15,"is_preprint":false},{"pmid":"31562761","id":"PMC_31562761","title":"Hexa-Longin domain scaffolds for inter-Rab signalling.","date":"2020","source":"Bioinformatics (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/31562761","citation_count":13,"is_preprint":false},{"pmid":"21853108","id":"PMC_21853108","title":"Specificity of RSG-1.2 peptide binding to RRE-IIB RNA element of HIV-1 over Rev peptide is mainly enthalpic in origin.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21853108","citation_count":11,"is_preprint":false},{"pmid":"33343632","id":"PMC_33343632","title":"Improved Detection of Potentially Pleiotropic Genes in Coronary Artery Disease and Chronic Kidney Disease Using GWAS Summary Statistics.","date":"2020","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/33343632","citation_count":8,"is_preprint":false},{"pmid":"12475335","id":"PMC_12475335","title":"Displacement of Mn2+ from RNA by K+, Mg2+, neomycin B, and an arginine-rich peptide: indirect detection of nucleic acid/ligand interactions using phosphorus relaxation enhancement.","date":"2002","source":"Journal of the American Chemical Society","url":"https://pubmed.ncbi.nlm.nih.gov/12475335","citation_count":7,"is_preprint":false},{"pmid":"35833626","id":"PMC_35833626","title":"Role of Mutations in Differential Recognition of Viral RNA Molecules by Peptides.","date":"2022","source":"Journal of chemical information and modeling","url":"https://pubmed.ncbi.nlm.nih.gov/35833626","citation_count":7,"is_preprint":false},{"pmid":"37317292","id":"PMC_37317292","title":"Integrated Microbiota and Metabolome Analysis to Assess the Effects of the Solid-State Fermentation of Corn-Soybean Meal Feed Using Compound Strains.","date":"2023","source":"Microorganisms","url":"https://pubmed.ncbi.nlm.nih.gov/37317292","citation_count":7,"is_preprint":false},{"pmid":"7410812","id":"PMC_7410812","title":"Necator americanus in infant rabbits: complete development, humoral antibody, leukocyte response and serum protein changes following infection.","date":"1980","source":"Journal of helminthology","url":"https://pubmed.ncbi.nlm.nih.gov/7410812","citation_count":7,"is_preprint":false},{"pmid":"36479942","id":"PMC_36479942","title":"Characterization of Rsg3, a novel greenbug resistance gene from the Chinese barley landrace PI 565676.","date":"2022","source":"The plant genome","url":"https://pubmed.ncbi.nlm.nih.gov/36479942","citation_count":6,"is_preprint":false},{"pmid":"40593758","id":"PMC_40593758","title":"The human ciliopathy protein RSG1 links the CPLANE complex to transition zone architecture.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/40593758","citation_count":4,"is_preprint":false},{"pmid":"38721990","id":"PMC_38721990","title":"RSG1 is required for cilia-dependent neural tube closure.","date":"2024","source":"Genesis (New York, N.Y. : 2000)","url":"https://pubmed.ncbi.nlm.nih.gov/38721990","citation_count":3,"is_preprint":false},{"pmid":"3040695","id":"PMC_3040695","title":"Physical map of the Rhodobacter sphaeroides bacteriophage phi RsG1 genome and location of the prophage on the host chromosome.","date":"1987","source":"Journal of bacteriology","url":"https://pubmed.ncbi.nlm.nih.gov/3040695","citation_count":3,"is_preprint":false},{"pmid":"38005694","id":"PMC_38005694","title":"Genetic Diversity of Barley Accessions from East Asia for Greenbug Resistance.","date":"2023","source":"Plants (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/38005694","citation_count":3,"is_preprint":false},{"pmid":"33323039","id":"PMC_33323039","title":"Probing the mechanism of peptide binding to REV response element RNA of HIV-1; MD simulations and free energy calculations.","date":"2020","source":"Journal of biomolecular structure & dynamics","url":"https://pubmed.ncbi.nlm.nih.gov/33323039","citation_count":3,"is_preprint":false},{"pmid":"18569791","id":"PMC_18569791","title":"Tailoring the peptide-binding specificity of an RNA by combinations of specificity-altering mutations.","date":"2008","source":"Nucleosides, nucleotides & nucleic acids","url":"https://pubmed.ncbi.nlm.nih.gov/18569791","citation_count":3,"is_preprint":false},{"pmid":"30856952","id":"PMC_30856952","title":"Inheritance of Complete Resistance to Pearl Millet Downy Mildew.","date":"1998","source":"Plant disease","url":"https://pubmed.ncbi.nlm.nih.gov/30856952","citation_count":3,"is_preprint":false},{"pmid":"38093595","id":"PMC_38093595","title":"Identification of a new Rsg1 allele conferring resistance to multiple greenbug biotypes from barley accessions PI 499276 and PI 566459.","date":"2023","source":"The plant genome","url":"https://pubmed.ncbi.nlm.nih.gov/38093595","citation_count":2,"is_preprint":false},{"pmid":"39510979","id":"PMC_39510979","title":"Characterization of a new barley greenbug resistance gene Rsg4 in the Chinese landrace CI 2458.","date":"2024","source":"The plant genome","url":"https://pubmed.ncbi.nlm.nih.gov/39510979","citation_count":2,"is_preprint":false},{"pmid":"39755226","id":"PMC_39755226","title":"Moderate levels of folic acid benefit outcomes for cilia based neural tube defects.","date":"2025","source":"Developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/39755226","citation_count":2,"is_preprint":false},{"pmid":"14510450","id":"PMC_14510450","title":"The variability of the peptide-binding specificity of RNA.","date":"2003","source":"Nucleic acids research. Supplement (2001)","url":"https://pubmed.ncbi.nlm.nih.gov/14510450","citation_count":2,"is_preprint":false},{"pmid":"18776229","id":"PMC_18776229","title":"Manipulation of the peptide-binding specificity of an RNA in a rational manner by combinations of specificity-altering mutations.","date":"2008","source":"Nucleic acids symposium series (2004)","url":"https://pubmed.ncbi.nlm.nih.gov/18776229","citation_count":2,"is_preprint":false},{"pmid":"39386566","id":"PMC_39386566","title":"The human ciliopathy protein RSG1 links the CPLANE complex to transition zone architecture.","date":"2024","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/39386566","citation_count":1,"is_preprint":false},{"pmid":"41952398","id":"PMC_41952398","title":"Phenotypic Expansion and Molecular Implications in Recessive FUZ-Related Ciliopathy.","date":"2026","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/41952398","citation_count":0,"is_preprint":false},{"pmid":"10780455","id":"PMC_10780455","title":"In vivo selection of RNA-binding peptides from combinatorial libraries.","date":"1999","source":"Nucleic acids symposium series","url":"https://pubmed.ncbi.nlm.nih.gov/10780455","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":14929,"output_tokens":2062,"usd":0.037859,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9071,"output_tokens":2235,"usd":0.050615,"stage2_stop_reason":"end_turn"},"total_usd":0.088474,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"RSG1 (CPLANE2) localizes to the mother centriole in a process that depends on tau tubulin kinase 2 (TTBK2), the CPLANE complex protein Inturned (INTU), and its own GTPase activity. Mouse embryos lacking RSG1 die at E12.5 with decreased Hedgehog signaling; mutant mother centrioles recruit cilia initiation proteins and dock onto ciliary vesicles, but axonemal microtubules fail to elongate, indicating RSG1 acts at a final maturation step of the mother centriole/ciliary vesicle to allow axonemal extension.\",\n      \"method\": \"Mouse knockout (loss-of-function), live imaging/immunofluorescence localization, genetic dependency analysis (TTBK2/INTU mutant backgrounds), GTPase activity assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO with defined cellular phenotype, multiple orthogonal methods (localization, epistasis, GTPase activity), replicated across genetic contexts\",\n      \"pmids\": [\"29038301\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Rsg1 (CPLANE2) is required for normal axonemal IFT dynamics in multiciliated cells, for cytoplasmic localization of the retrograde IFT-A protein IFT43, and for apical localization of basal bodies. Loss of Rsg1 in Xenopus impairs all three processes, placing RSG1 as a regulator of multiple aspects of ciliogenesis including basal body trafficking and IFT protein localization.\",\n      \"method\": \"Morpholino-based loss-of-function in Xenopus multiciliated cells, live imaging of IFT dynamics, immunofluorescence localization of IFT43 and basal body markers\",\n      \"journal\": \"Cilia\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KD with defined cellular phenotypes, multiple readouts in a single lab/study\",\n      \"pmids\": [\"24192041\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A point mutation in the GTP-binding pocket (G1 domain) of RSG1 in the mouse L3P mutant disrupts Sonic hedgehog signaling and cilia initiation. The mutant RSG1 protein and other centrosomal/IFT proteins still localize to the basal body, indicating that RSG1 GTPase activity is not required for basal body maturation but is needed for a downstream step in axonemal elongation.\",\n      \"method\": \"Forward genetic screen, point mutation mapping, immunofluorescence localization of RSG1 and IFT proteins in mutant vs. wild-type mouse embryos\",\n      \"journal\": \"Genesis (New York, N.Y. : 2000)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — defined point mutation in GTP-binding domain, multiple localization readouts, single lab\",\n      \"pmids\": [\"38721990\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Affinity purification mass spectrometry (APMS) shows that RSG1 (CPLANE2) binds the CPLANE complex and the transition zone protein FAM92 in a GTP-dependent manner. Disease-associated variants in CPLANE2/RSG1 disrupt two vital steps of ciliogenesis: basal body docking and recruitment of intraflagellar transport proteins. CPLANE is required for normal transition zone architecture.\",\n      \"method\": \"Affinity purification mass spectrometry (APMS), patient-derived variant analysis, ciliogenesis assays (basal body docking, IFT recruitment), transition zone architecture imaging\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — APMS binding data with GTP-dependency, functional assays with patient variants, multiple orthogonal methods, peer-reviewed publication\",\n      \"pmids\": [\"40593758\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"RSG1 (CPLANE2) binds the CPLANE complex and the transition zone protein FAM92 in a GTP-dependent manner (preprint version of the same finding, independently confirming the peer-reviewed result).\",\n      \"method\": \"Affinity purification mass spectrometry (APMS), GTP-dependency assay, ciliogenesis functional assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — APMS with GTP-dependency, single lab, preprint prior to peer-reviewed publication\",\n      \"pmids\": [\"39386566\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Folic acid at moderate levels benefits cilia-based neural tube defects in RSG1 mutant mice. The proposed mechanism is that fortified FA levels reduce basal reactive oxygen species (ROS), which in turn reduces ROS-sensitive GTPase activity required for ciliogenesis, suggesting RSG1 GTPase activity is ROS-sensitive.\",\n      \"method\": \"Mouse NTD models with Rsg1 mutation, folic acid dosage experiments, ROS measurement, cilia formation assays\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, proposed ROS-GTPase mechanism not directly validated for RSG1 specifically\",\n      \"pmids\": [\"39755226\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Bioinformatic analysis identifies INTU and FUZ (CPLANE complex partners of RSG1) as novel members of homologous HerMon complexes containing tripled Longin domains, suggesting INTU/FUZ may act as GEFs for Rab GTPases during ciliogenesis, providing structural context for how RSG1 operates within the CPLANE complex.\",\n      \"method\": \"Evolutionary coevolution-based contact prediction and sequence conservation analysis (computational)\",\n      \"journal\": \"Bioinformatics (Oxford, England)\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — computational prediction only, no direct experimental validation of RSG1 specifically\",\n      \"pmids\": [\"31562761\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2030,\n      \"finding\": \"In silico three-dimensional structural analysis predicts that a pathogenic FUZ variant alters interactions between FUZ and CPLANE2 (RSG1), potentially disrupting ciliogenesis. This supports a direct physical interaction between FUZ and RSG1 within the CPLANE complex.\",\n      \"method\": \"In silico 3D structural analysis of variant effect on FUZ–RSG1 interaction\",\n      \"journal\": \"Clinical genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — computational structural prediction only, no direct experimental validation of the FUZ–RSG1 interaction\",\n      \"pmids\": [\"41952398\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CPLANE2/RSG1 is a small GTPase that localizes to the mother centriole in a TTBK2- and INTU-dependent manner and is required for a final step in cilia initiation—specifically, axonemal microtubule elongation after basal body docking onto ciliary vesicles—through its GTPase activity; it physically binds the CPLANE complex (via INTU/FUZ) and the transition zone protein FAM92 in a GTP-dependent manner, and its loss disrupts basal body docking, IFT protein recruitment, IFT dynamics, and transition zone architecture, causing ciliopathy in humans and mice.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CPLANE2 (RSG1) is a small GTPase that governs a late maturation step of ciliogenesis at the mother centriole, where it is required for axonemal microtubule elongation after the basal body has docked onto ciliary vesicles [#0]. It localizes to the mother centriole in a manner dependent on tau tubulin kinase 2 (TTBK2), the CPLANE complex protein Inturned (INTU), and its own GTPase activity, and its loss in mouse embryos produces lethality with diminished Hedgehog signaling despite proper recruitment of cilia initiation proteins and ciliary vesicle docking [#0]. A point mutation in the GTP-binding (G1) pocket disrupts Hedgehog signaling and cilia initiation without preventing basal body localization of RSG1 or IFT proteins, establishing that its GTPase activity acts downstream of basal body maturation to drive axonemal extension [#2]. CPLANE2 physically associates with the CPLANE complex and the transition zone protein FAM92 in a GTP-dependent manner, and its disease-associated variants disrupt basal body docking, intraflagellar transport protein recruitment, and transition zone architecture, causing ciliopathy in humans [#3]. Across multiciliated cells it additionally regulates axonemal IFT dynamics, cytoplasmic localization of the retrograde IFT-A protein IFT43, and apical positioning of basal bodies [#1].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Established RSG1 as a multi-functional ciliogenesis regulator by showing it is needed for IFT dynamics, IFT43 localization, and basal body trafficking, moving it beyond a single discrete role.\",\n      \"evidence\": \"Morpholino loss-of-function in Xenopus multiciliated cells with live IFT imaging and marker immunofluorescence\",\n      \"pmids\": [\"24192041\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not define the molecular activity linking RSG1 to IFT\", \"Knockdown specificity not orthogonally validated\", \"No direct partner identified\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Placed RSG1 at a defined point in the ciliogenesis pathway by showing its mother-centriole localization depends on TTBK2, INTU, and GTPase activity, and that its loss blocks axonemal elongation after vesicle docking.\",\n      \"evidence\": \"Mouse knockout with localization imaging, genetic epistasis in TTBK2/INTU backgrounds, and GTPase activity assays\",\n      \"pmids\": [\"29038301\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct molecular effectors of axonemal elongation not identified\", \"How GTPase cycling is regulated at the centriole unknown\", \"Mechanism connecting RSG1 to Hedgehog signaling not resolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Separated RSG1's structural localization role from its catalytic role by showing a G1-domain point mutation blocks cilia initiation while leaving basal body localization of RSG1 and IFT proteins intact.\",\n      \"evidence\": \"Forward genetic screen and point mutation mapping with localization imaging in mutant vs wild-type mouse embryos\",\n      \"pmids\": [\"38721990\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"GTP-loaded effector engaged during elongation not identified\", \"Single lab, single allele\", \"Does not explain how GTP hydrolysis is coupled to axonemal extension\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified the physical partners of RSG1 and tied human disease variants to specific ciliogenesis failures, defining how RSG1 operates within the CPLANE complex and at the transition zone.\",\n      \"evidence\": \"Affinity purification mass spectrometry with GTP-dependency, patient-variant functional ciliogenesis assays, and transition zone imaging (peer-reviewed; preceded by a confirming preprint)\",\n      \"pmids\": [\"40593758\", \"39386566\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct vs indirect nature of the FAM92 interaction not fully resolved\", \"Structural basis of GTP-dependent binding undefined\", \"Order of events linking docking, IFT recruitment, and transition zone assembly unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Proposed that RSG1 GTPase activity is redox-sensitive, offering a mechanistic rationale for folic acid rescue of neural tube defects in mutant mice.\",\n      \"evidence\": \"Rsg1 mutant mouse NTD models with folic acid dosing, ROS measurement, and cilia formation assays\",\n      \"pmids\": [\"39755226\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"ROS-sensitivity of RSG1 GTPase activity not directly validated for the protein\", \"Single lab\", \"Mechanism is proposed, not biochemically demonstrated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The downstream GTP-dependent effector through which RSG1 drives axonemal microtubule elongation, and the structural basis of its CPLANE/FAM92 engagement, remain undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No identified effector executing axonemal extension\", \"No experimental structure of the RSG1-CPLANE-FAM92 assembly\", \"Regulator of RSG1 GTP/GDP cycling at the centriole unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003924\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [\"CPLANE complex\"],\n    \"partners\": [\"INTU\", \"FUZ\", \"FAM92\", \"TTBK2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}