{"gene":"PF3D7_0619700","run_date":"2026-09-08T12:51:26","timeline":{"discoveries":[{"year":2023,"finding":"In Plasmodium berghei, FBXO1 forms a functional SKP1/Cullin1/FBXO1 (SCF^FBXO1) E3 ubiquitin ligase complex; this complex is required for nuclear segregation during schizogony and centrosome partitioning during microgametogenesis, gamete egress from host erythrocytes, and integrity of the apical complex and inner membrane complex (IMC) in merozoites and ookinetes.","method":"Conditional knockdown/genetic manipulation, ubiquitinomic mass spectrometry, immunofluorescence localization across developmental stages","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (ubiquitinomics, localization, functional knockdown across multiple life-cycle stages) in a single rigorous study with defined cellular phenotypes","pmids":["36898988"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2023,"finding":"In Plasmodium berghei, FBXO1-dependent ubiquitination intersects with phosphorylation by calcium-dependent protein kinase 1 (CDPK1), establishing a regulatory interplay between SCF^FBXO1-mediated ubiquitination and CDPK1-mediated phosphorylation.","method":"Ubiquitinomic profiling in FBXO1-depleted parasites combined with phosphoproteomics","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mass-spectrometry-based evidence from a single lab demonstrating pathway interplay, but no direct biochemical reconstitution of the FBXO1–CDPK1 link","pmids":["36898988"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2024,"finding":"In Plasmodium falciparum, FBXO1 (PfFBXO1) is a component of a functional SCF complex (PfSCF) comprising PfCullin-1, PfRbx1, PfSkp1, PfFBXO1, and calcyclin binding protein, confirmed to have E3 ubiquitin ligase activity.","method":"Co-immunoprecipitation, in vitro protein–protein interaction assay, in vitro ubiquitination assay","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro ubiquitination assay plus reciprocal immunoprecipitation and direct protein-protein interaction assay, multiple orthogonal methods in one study","pmids":["38416790"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"finding":"PfFBXO1 (PF3D7_0619700) localizes initially to the apical region of dividing P. falciparum merozoites and transitions to an IMC-like localization as segmentation progresses; it also localizes to the IMC region unilaterally in gametocytes, directly linking its subcellular position to IMC biogenesis.","method":"Live/immunofluorescence imaging across asexual and gametocyte stages following epitope tagging","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization by fluorescence imaging tied to functional consequence via inducible knockout, single lab","pmids":["39915671"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"finding":"Inducible knockout of PfFBXO1 in P. falciparum causes abnormal segmentation and karyokinesis, producing inviable daughter merozoites, and results in abnormally shaped gametocytes that fail to fully mature, demonstrating an essential role in both asexual IMC-dependent cytokinesis and sexual stage development.","method":"Inducible knockout (conditional genetics), morphological and viability assays, flow cytometry","journal":"Communications biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean inducible knockout with specific, quantified cellular phenotypes in two developmental stages using orthogonal readouts in a focused study","pmids":["39915671"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"finding":"Proteomic analysis of PfFBXO1 immunoprecipitates identified PfSKP1 as a stable interacting partner, and multiple IMC pellicle and membrane proteins as co-purifying partners, consistent with PfFBXO1 functioning at the IMC scaffold.","method":"Co-immunoprecipitation followed by mass spectrometry (proteomic interactome)","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single Co-IP/MS experiment from one lab; PfSKP1 interaction is consistent with other studies but not independently validated by reciprocal pull-down in this paper","pmids":["39915671"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"In Plasmodium yoelii, the fbxo1 gene product was successfully tagged with an auxin-inducible degron (AID) motif enabling conditional proteasomal degradation, confirming the protein is expressed in asexual schizont and sexual gametocyte stages and can be depleted in those stages using auxin.","method":"CRISPR/Cas9 genome editing to introduce AID tag; auxin-induced degradation confirmed by western blot","journal":"Molecular and biochemical parasitology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single-method demonstration of conditional depletion; no downstream mechanistic phenotype for FBXO1 specifically reported in the abstract","pmids":["33307135"],"is_preprint":false,"attribution":[{"species":"Plasmodium yoelii","strain":""}]}],"current_model":"PfFBXO1/FBXO1 (PF3D7_0619700) is the substrate-recognition subunit of a conserved SCF (SKP1–Cullin1–FBXO1) E3 ubiquitin ligase complex in Plasmodium; this complex localizes to the inner membrane complex (IMC) initiation scaffold at the apical region of developing merozoites and in gametocytes, where it is essential for IMC biogenesis, correct nuclear segregation/karyokinesis during schizogony, centrosome partitioning during microgametogenesis, gamete egress, and gametocyte maturation, with its ubiquitination activity functionally linked to CDPK1-mediated phosphorylation signaling."},"narrative":{"mechanistic_narrative":"FBXO1 (PF3D7_0619700) is the substrate-recognition F-box subunit of a conserved SCF (SKP1–Cullin1–FBXO1) E3 ubiquitin ligase in Plasmodium that governs inner membrane complex (IMC) biogenesis and cell division across asexual and sexual life-cycle stages [PMID:36898988, PMID:38416790]. In P. falciparum the protein assembles into a functional SCF complex (PfCullin-1, PfRbx1, PfSkp1, PfFBXO1, and calcyclin-binding protein) with demonstrated in vitro ubiquitination activity, with PfSKP1 as its stable interacting partner [PMID:38416790, PMID:39915671]. FBXO1 localizes to the apical region of dividing merozoites and transitions to an IMC-like distribution during segmentation, and occupies a unilateral IMC region in gametocytes, tying its position to IMC assembly [PMID:39915671]. Inducible depletion in P. falciparum causes abnormal segmentation and karyokinesis yielding inviable merozoites, and malformed gametocytes that fail to mature [PMID:39915671]; in P. berghei, loss of the SCF^FBXO1 complex disrupts nuclear segregation during schizogony, centrosome partitioning during microgametogenesis, gamete egress, and apical/IMC integrity [PMID:36898988]. Its ubiquitination activity intersects with CDPK1-mediated phosphorylation signaling [PMID:36898988]. The identity of FBXO1's ubiquitination substrates and the biochemical basis of the FBXO1–CDPK1 link have not been resolved in the available corpus.","teleology":[{"year":2020,"claim":"Before mechanism could be probed, a tool was needed to deplete FBXO1 in the stages where it acts; tagging the fbxo1 product with an auxin-inducible degron established that the protein is expressed in schizonts and gametocytes and can be conditionally degraded.","evidence":"CRISPR/Cas9 AID tagging with auxin-induced degradation confirmed by western blot in P. yoelii","pmids":["33307135"],"confidence":"Low","gaps":["No downstream FBXO1-specific phenotype reported","Does not establish complex membership or enzymatic activity","Single-method demonstration"],"attribution":[{"species":"Plasmodium yoelii","strain":""}]},{"year":2023,"claim":"It was unknown whether FBXO1 functions as an E3 ligase in vivo and what cellular processes it controls; genetic depletion combined with ubiquitinomics showed it forms a functional SCF^FBXO1 complex essential for nuclear segregation, centrosome partitioning, gamete egress, and apical/IMC integrity.","evidence":"Conditional knockdown, ubiquitinomic mass spectrometry, and stage-resolved immunofluorescence in P. berghei","pmids":["36898988"],"confidence":"High","gaps":["Specific ubiquitination substrates not defined","No structural model of the complex","Mechanism linking ubiquitination to IMC integrity unresolved"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2023,"claim":"How FBXO1 activity integrates with other regulatory signals was unknown; comparing ubiquitinome and phosphoproteome upon FBXO1 depletion revealed an interplay between SCF^FBXO1 ubiquitination and CDPK1-mediated phosphorylation.","evidence":"Ubiquitinomic profiling in FBXO1-depleted parasites combined with phosphoproteomics in P. berghei","pmids":["36898988"],"confidence":"Medium","gaps":["No direct biochemical reconstitution of the FBXO1–CDPK1 link","Directionality of the ubiquitination/phosphorylation crosstalk unclear","Shared substrates not defined"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2024,"claim":"Whether the human-pathogen species retains the same complex and enzymatic activity was untested; reconstitution and interaction assays confirmed PfFBXO1 is part of a functional PfSCF complex with in vitro ubiquitination activity.","evidence":"Co-immunoprecipitation, in vitro protein–protein interaction assay, and in vitro ubiquitination assay in P. falciparum","pmids":["38416790"],"confidence":"High","gaps":["Physiological substrates of the ligase not identified","Role of calcyclin-binding protein in substrate selection unknown"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"claim":"The subcellular basis of FBXO1 function was unresolved; imaging showed it localizes apically in dividing merozoites and transitions to an IMC-like distribution and a unilateral IMC region in gametocytes, and inducible knockout produced abnormal segmentation/karyokinesis and immature gametocytes, tying FBXO1 to IMC-dependent division in both asexual and sexual stages.","evidence":"Epitope-tagged live/immunofluorescence imaging, inducible knockout with morphological/viability assays and Co-IP/MS in P. falciparum","pmids":["39915671"],"confidence":"High","gaps":["Mechanism recruiting FBXO1 to the apical/IMC scaffold unknown","Co-purifying IMC proteins not validated as ubiquitination substrates","PfSKP1 interaction not reciprocally validated in this study"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"The direct ubiquitination substrates of FBXO1 at the IMC scaffold and the biochemical mechanism coupling its ligase activity to CDPK1 phosphorylation signaling remain to be defined.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No validated in vivo ubiquitination substrate","No structural model of substrate recognition","Mechanistic basis of ubiquitination/phosphorylation crosstalk unresolved"],"attribution":[]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["SCF^FBXO1 E3 ubiquitin ligase complex (SKP1–Cullin1–FBXO1)","PfSCF complex (PfCullin-1, PfRbx1, PfSkp1, PfFBXO1, calcyclin-binding protein)"],"partners":["SKP1 / PFSKP1","CULLIN-1 / PFCULLIN-1","PFRBX1","CALCYCLIN-BINDING PROTEIN","CDPK1 (FUNCTIONAL PATHWAY INTERPLAY)"],"other_free_text":["Substrate-recognition F-box subunit of a Plasmodium SCF E3 ubiquitin ligase.","Essential for inner membrane complex (IMC) biogenesis and cytokinesis in asexual schizonts and for gametocyte maturation.","Required for correct nuclear segregation/karyokinesis during schizogony and centrosome partitioning during microgametogenesis (P. berghei).","Ubiquitination activity functionally linked to CDPK1-mediated phosphorylation, but no direct ubiquitination substrate identified in the corpus."]}},"prefetch_data":{},"corpus_meta":[{"pmid":"36898988","id":"PMC_36898988","title":"The Skp1-Cullin1-FBXO1 complex is a pleiotropic regulator required for the formation of gametes and motile forms in Plasmodium berghei.","date":"2023","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/36898988","citation_count":16,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["FBXO1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"38416790","id":"PMC_38416790","title":"Plasmodium falciparum contains functional SCF and CRL4 ubiquitin E3 ligases, and CRL4 is critical for cell division and membrane integrity.","date":"2024","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/38416790","citation_count":12,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfFBXO1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"33307135","id":"PMC_33307135","title":"Generation of Plasmodium yoelii malaria parasite for conditional degradation of proteins.","date":"2020","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/33307135","citation_count":11,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["FBXO1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"39915671","id":"PMC_39915671","title":"PfFBXO1 is essential for inner membrane complex formation in Plasmodium falciparum during both asexual and transmission stages.","date":"2025","source":"Communications biology","url":"https://pubmed.ncbi.nlm.nih.gov/39915671","citation_count":5,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["FBXO1","PfFBXO1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":5083,"output_tokens":1991,"usd":0.022557,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":7182,"output_tokens":3008,"usd":0.055555,"stage2_stop_reason":"end_turn"},"total_usd":0.078112,"stage1_batch_id":"msgbatch_01DisAaTypwmC8QwdMBuePHo","stage2_batch_id":"msgbatch_0184zxZTqxiEfdYYfPMfkqjb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2023,\n      \"finding\": \"In Plasmodium berghei, FBXO1 forms a functional SKP1/Cullin1/FBXO1 (SCF^FBXO1) E3 ubiquitin ligase complex; this complex is required for nuclear segregation during schizogony and centrosome partitioning during microgametogenesis, gamete egress from host erythrocytes, and integrity of the apical complex and inner membrane complex (IMC) in merozoites and ookinetes.\",\n      \"method\": \"Conditional knockdown/genetic manipulation, ubiquitinomic mass spectrometry, immunofluorescence localization across developmental stages\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (ubiquitinomics, localization, functional knockdown across multiple life-cycle stages) in a single rigorous study with defined cellular phenotypes\",\n      \"pmids\": [\"36898988\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In Plasmodium berghei, FBXO1-dependent ubiquitination intersects with phosphorylation by calcium-dependent protein kinase 1 (CDPK1), establishing a regulatory interplay between SCF^FBXO1-mediated ubiquitination and CDPK1-mediated phosphorylation.\",\n      \"method\": \"Ubiquitinomic profiling in FBXO1-depleted parasites combined with phosphoproteomics\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mass-spectrometry-based evidence from a single lab demonstrating pathway interplay, but no direct biochemical reconstitution of the FBXO1–CDPK1 link\",\n      \"pmids\": [\"36898988\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In Plasmodium falciparum, FBXO1 (PfFBXO1) is a component of a functional SCF complex (PfSCF) comprising PfCullin-1, PfRbx1, PfSkp1, PfFBXO1, and calcyclin binding protein, confirmed to have E3 ubiquitin ligase activity.\",\n      \"method\": \"Co-immunoprecipitation, in vitro protein–protein interaction assay, in vitro ubiquitination assay\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro ubiquitination assay plus reciprocal immunoprecipitation and direct protein-protein interaction assay, multiple orthogonal methods in one study\",\n      \"pmids\": [\"38416790\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PfFBXO1 (PF3D7_0619700) localizes initially to the apical region of dividing P. falciparum merozoites and transitions to an IMC-like localization as segmentation progresses; it also localizes to the IMC region unilaterally in gametocytes, directly linking its subcellular position to IMC biogenesis.\",\n      \"method\": \"Live/immunofluorescence imaging across asexual and gametocyte stages following epitope tagging\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization by fluorescence imaging tied to functional consequence via inducible knockout, single lab\",\n      \"pmids\": [\"39915671\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Inducible knockout of PfFBXO1 in P. falciparum causes abnormal segmentation and karyokinesis, producing inviable daughter merozoites, and results in abnormally shaped gametocytes that fail to fully mature, demonstrating an essential role in both asexual IMC-dependent cytokinesis and sexual stage development.\",\n      \"method\": \"Inducible knockout (conditional genetics), morphological and viability assays, flow cytometry\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean inducible knockout with specific, quantified cellular phenotypes in two developmental stages using orthogonal readouts in a focused study\",\n      \"pmids\": [\"39915671\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Proteomic analysis of PfFBXO1 immunoprecipitates identified PfSKP1 as a stable interacting partner, and multiple IMC pellicle and membrane proteins as co-purifying partners, consistent with PfFBXO1 functioning at the IMC scaffold.\",\n      \"method\": \"Co-immunoprecipitation followed by mass spectrometry (proteomic interactome)\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single Co-IP/MS experiment from one lab; PfSKP1 interaction is consistent with other studies but not independently validated by reciprocal pull-down in this paper\",\n      \"pmids\": [\"39915671\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In Plasmodium yoelii, the fbxo1 gene product was successfully tagged with an auxin-inducible degron (AID) motif enabling conditional proteasomal degradation, confirming the protein is expressed in asexual schizont and sexual gametocyte stages and can be depleted in those stages using auxin.\",\n      \"method\": \"CRISPR/Cas9 genome editing to introduce AID tag; auxin-induced degradation confirmed by western blot\",\n      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single-method demonstration of conditional depletion; no downstream mechanistic phenotype for FBXO1 specifically reported in the abstract\",\n      \"pmids\": [\"33307135\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium yoelii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"PfFBXO1/FBXO1 (PF3D7_0619700) is the substrate-recognition subunit of a conserved SCF (SKP1–Cullin1–FBXO1) E3 ubiquitin ligase complex in Plasmodium; this complex localizes to the inner membrane complex (IMC) initiation scaffold at the apical region of developing merozoites and in gametocytes, where it is essential for IMC biogenesis, correct nuclear segregation/karyokinesis during schizogony, centrosome partitioning during microgametogenesis, gamete egress, and gametocyte maturation, with its ubiquitination activity functionally linked to CDPK1-mediated phosphorylation signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"FBXO1 (PF3D7_0619700) is the substrate-recognition F-box subunit of a conserved SCF (SKP1–Cullin1–FBXO1) E3 ubiquitin ligase in Plasmodium that governs inner membrane complex (IMC) biogenesis and cell division across asexual and sexual life-cycle stages [#0, #2]. In P. falciparum the protein assembles into a functional SCF complex (PfCullin-1, PfRbx1, PfSkp1, PfFBXO1, and calcyclin-binding protein) with demonstrated in vitro ubiquitination activity, with PfSKP1 as its stable interacting partner [#2, #5]. FBXO1 localizes to the apical region of dividing merozoites and transitions to an IMC-like distribution during segmentation, and occupies a unilateral IMC region in gametocytes, tying its position to IMC assembly [#3]. Inducible depletion in P. falciparum causes abnormal segmentation and karyokinesis yielding inviable merozoites, and malformed gametocytes that fail to mature [#4]; in P. berghei, loss of the SCF^FBXO1 complex disrupts nuclear segregation during schizogony, centrosome partitioning during microgametogenesis, gamete egress, and apical/IMC integrity [#0]. Its ubiquitination activity intersects with CDPK1-mediated phosphorylation signaling [#1]. The identity of FBXO1's ubiquitination substrates and the biochemical basis of the FBXO1–CDPK1 link have not been resolved in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2020,\n      \"claim\": \"Before mechanism could be probed, a tool was needed to deplete FBXO1 in the stages where it acts; tagging the fbxo1 product with an auxin-inducible degron established that the protein is expressed in schizonts and gametocytes and can be conditionally degraded.\",\n      \"evidence\": \"CRISPR/Cas9 AID tagging with auxin-induced degradation confirmed by western blot in P. yoelii\",\n      \"pmids\": [\"33307135\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No downstream FBXO1-specific phenotype reported\", \"Does not establish complex membership or enzymatic activity\", \"Single-method demonstration\"],\n      \"attribution\": [{\"species\": \"Plasmodium yoelii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"It was unknown whether FBXO1 functions as an E3 ligase in vivo and what cellular processes it controls; genetic depletion combined with ubiquitinomics showed it forms a functional SCF^FBXO1 complex essential for nuclear segregation, centrosome partitioning, gamete egress, and apical/IMC integrity.\",\n      \"evidence\": \"Conditional knockdown, ubiquitinomic mass spectrometry, and stage-resolved immunofluorescence in P. berghei\",\n      \"pmids\": [\"36898988\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific ubiquitination substrates not defined\", \"No structural model of the complex\", \"Mechanism linking ubiquitination to IMC integrity unresolved\"],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"How FBXO1 activity integrates with other regulatory signals was unknown; comparing ubiquitinome and phosphoproteome upon FBXO1 depletion revealed an interplay between SCF^FBXO1 ubiquitination and CDPK1-mediated phosphorylation.\",\n      \"evidence\": \"Ubiquitinomic profiling in FBXO1-depleted parasites combined with phosphoproteomics in P. berghei\",\n      \"pmids\": [\"36898988\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct biochemical reconstitution of the FBXO1–CDPK1 link\", \"Directionality of the ubiquitination/phosphorylation crosstalk unclear\", \"Shared substrates not defined\"],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Whether the human-pathogen species retains the same complex and enzymatic activity was untested; reconstitution and interaction assays confirmed PfFBXO1 is part of a functional PfSCF complex with in vitro ubiquitination activity.\",\n      \"evidence\": \"Co-immunoprecipitation, in vitro protein–protein interaction assay, and in vitro ubiquitination assay in P. falciparum\",\n      \"pmids\": [\"38416790\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological substrates of the ligase not identified\", \"Role of calcyclin-binding protein in substrate selection unknown\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"The subcellular basis of FBXO1 function was unresolved; imaging showed it localizes apically in dividing merozoites and transitions to an IMC-like distribution and a unilateral IMC region in gametocytes, and inducible knockout produced abnormal segmentation/karyokinesis and immature gametocytes, tying FBXO1 to IMC-dependent division in both asexual and sexual stages.\",\n      \"evidence\": \"Epitope-tagged live/immunofluorescence imaging, inducible knockout with morphological/viability assays and Co-IP/MS in P. falciparum\",\n      \"pmids\": [\"39915671\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism recruiting FBXO1 to the apical/IMC scaffold unknown\", \"Co-purifying IMC proteins not validated as ubiquitination substrates\", \"PfSKP1 interaction not reciprocally validated in this study\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The direct ubiquitination substrates of FBXO1 at the IMC scaffold and the biochemical mechanism coupling its ligase activity to CDPK1 phosphorylation signaling remain to be defined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No validated in vivo ubiquitination substrate\", \"No structural model of substrate recognition\", \"Mechanistic basis of ubiquitination/phosphorylation crosstalk unresolved\"],\n      \"attribution\": []\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0061630\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0004842\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0020039\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0020007\", \"supporting_discovery_ids\": [0, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0016567\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0000278\", \"supporting_discovery_ids\": [0, 4]},\n      {\"term_id\": \"GO:0007059\", \"supporting_discovery_ids\": [0, 4]}\n    ],\n    \"complexes\": [\n      \"SCF^FBXO1 E3 ubiquitin ligase complex (SKP1–Cullin1–FBXO1)\",\n      \"PfSCF complex (PfCullin-1, PfRbx1, PfSkp1, PfFBXO1, calcyclin-binding protein)\"\n    ],\n    \"partners\": [\n      \"SKP1 / PfSKP1\",\n      \"Cullin-1 / PfCullin-1\",\n      \"PfRbx1\",\n      \"calcyclin-binding protein\",\n      \"CDPK1 (functional pathway interplay)\"\n    ],\n    \"other_free_text\": [\n      \"Substrate-recognition F-box subunit of a Plasmodium SCF E3 ubiquitin ligase.\",\n      \"Essential for inner membrane complex (IMC) biogenesis and cytokinesis in asexual schizonts and for gametocyte maturation.\",\n      \"Required for correct nuclear segregation/karyokinesis during schizogony and centrosome partitioning during microgametogenesis (P. berghei).\",\n      \"Ubiquitination activity functionally linked to CDPK1-mediated phosphorylation, but no direct ubiquitination substrate identified in the corpus.\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_0619700","name":null,"product":"F-box protein FBXO1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_1118900","name":null,"product":"F-box protein FBXO1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_1130600","name":null,"product":"F-box protein FBXO1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"","evaluation":null}