{"gene":"PF3D7_0107000","run_date":"2026-09-08T16:26:55","timeline":{"discoveries":[{"year":2008,"finding":"CEN1 (PfCEN1) is expressed in sporozoites, asexual blood forms, gametocytes, and oocysts, and immunoelectron microscopy localized it in close proximity to the nucleus of sporozoites and asexual schizonts; confocal and widefield double-staining with alpha-tubulin antibodies indicated association with the parasite centrosome. Episomal expression of PfCEN1 in a centrin knock-out Leishmania donovani line partially restored growth rate and rescued a cytokinesis defect, establishing a functional role in cell division.","method":"Immunofluorescence microscopy, immunoelectron microscopy, double-staining with alpha-tubulin antibodies, growth complementation assay in centrin-KO Leishmania donovani","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization by immuno-EM and IFA tied to functional consequence via cross-species complementation, single lab with two orthogonal methods","pmids":["18693242"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2023,"finding":"CEN1 (PfCen1) undergoes Ca2+-inducible liquid-liquid phase separation (LLPS) in vitro; recombinant PfCen1-6His formed droplets upon CaCl2 addition that dissolved upon EDTA chelation. The disordered N-terminus and calcium-binding EF-hand motifs were identified as essential features for this reversible biomolecular condensation. Live-cell STED microscopy of PfCen1-Halo in P. falciparum blood-stage parasites revealed liquid-like dynamics (wobbling droplet-like shapes and stretching/retracting structures) at the centriolar plaque. Inducible overexpression of PfCen1-GFP produced concentration-dependent extra-centrosomal condensate-like assemblies, with foci formation and dissolution timed to cell cycle progression.","method":"In vitro turbidity assay and widefield imaging of recombinant protein droplet formation; live-cell STED microscopy with HaloTag/fluorogenic dye; inducible episomal overexpression with time-lapse fluorescence microscopy","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro reconstitution of LLPS with calcium and EDTA reversal, mutagenesis-equivalent domain analysis (N-terminus/EF-hands), and orthogonal live-cell STED imaging in parasites, all in one rigorous study","pmids":["38150475"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":"3D7"}]},{"year":2023,"finding":"CEN1 (PfCen1) localizes to the extranuclear (outer) compartment of the centriolar plaque in P. falciparum blood-stage schizonts, and co-immunoprecipitation of PfCen1-GFP followed by mass spectrometry identified PfCen3 and the Sfi1-like protein PfSlp (PF3D7_0710000) as co-precipitating partners, placing CEN1 in a complex with PfSlp at the centriolar plaque.","method":"Co-immunoprecipitation with anti-GFP antibody on episomally expressed PfCen1-GFP, followed by mass spectrometry; reciprocal IP confirmation; STED microscopy co-localization with anti-centrin antibody","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP with MS identification and STED co-localization, single lab","pmids":["37130129"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":"3D7"}]}],"current_model":"P. falciparum CEN1 (PfCen1/PF3D7_0107000) is a calcium-binding EF-hand protein that localizes to the extranuclear compartment of the centriolar plaque during schizogony, where it participates in cell division; it undergoes reversible Ca2+-dependent liquid-liquid phase separation driven by its disordered N-terminus and EF-hand motifs, displays liquid-like dynamics at the centriolar plaque in live parasites, and physically interacts with PfCen3 and the Sfi1-like centriolar plaque protein PfSlp."},"narrative":{"mechanistic_narrative":"PF3D7_0107000 (CEN1) is a calcium-binding EF-hand centrin that functions in Plasmodium falciparum cell division, localizing to the centriolar plaque during schizogony [PMID:18693242, PMID:37130129]. It is expressed across multiple parasite life-cycle stages (sporozoites, asexual blood forms, gametocytes, oocysts) and associates with the parasite centrosome near the nucleus, and episomal expression rescues both a growth and a cytokinesis defect in a centrin-null Leishmania donovani line, establishing a conserved role in cell division [PMID:18693242]. Within blood-stage schizonts CEN1 occupies the extranuclear (outer) compartment of the centriolar plaque and physically interacts with PfCen3 and the Sfi1-like centriolar plaque protein PfSlp (PF3D7_0710000), as shown by reciprocal co-immunoprecipitation and mass spectrometry [PMID:37130129]. CEN1 undergoes reversible, Ca2+-dependent liquid-liquid phase separation in vitro that is dissolved by EDTA chelation and depends on its disordered N-terminus and EF-hand motifs, and it displays liquid-like dynamics at the centriolar plaque in live parasites, with condensate formation and dissolution timed to cell cycle progression [PMID:38150475]. Beyond these findings, no further mechanistic detail on CEN1 has been characterized in the available corpus.","teleology":[{"year":2008,"claim":"Establishing whether the P. falciparum centrin CEN1 has a functional role in cell division rather than merely being a centrosome-associated protein, this work tied its centrosomal localization to a division phenotype.","evidence":"Immuno-EM and IFA co-staining with alpha-tubulin locating CEN1 to the centrosome, plus cross-species growth/cytokinesis complementation in centrin-KO Leishmania donovani","pmids":["18693242"],"confidence":"Medium","gaps":["Complementation was done in a heterologous Leishmania system, not by loss-of-function in P. falciparum","Direct molecular partners at the centrosome were not identified","Stage-specific functional requirements were not dissected"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2023,"claim":"To define where CEN1 sits within the centriolar plaque and what it binds, this work resolved its extranuclear sub-compartment and identified its protein partners.","evidence":"Reciprocal anti-GFP co-immunoprecipitation of PfCen1-GFP with mass spectrometry and STED co-localization in P. falciparum 3D7 schizonts","pmids":["37130129"],"confidence":"Medium","gaps":["Interaction stoichiometry and directness (direct vs. bridged) with PfCen3 and PfSlp not resolved","Functional consequence of the CEN1-PfSlp interaction not tested by perturbation","Single-lab episomal-tag data without endogenous validation"],"attribution":[{"species":"Plasmodium falciparum","strain":"3D7"}]},{"year":2023,"claim":"To explain how CEN1 organizes at the centriolar plaque, this work showed it forms reversible calcium-dependent condensates, linking its EF-hand chemistry to a biophysical assembly mechanism.","evidence":"In vitro Ca2+-induced/EDTA-reversed LLPS of recombinant PfCen1-6His with N-terminus/EF-hand domain analysis, plus live-cell STED and inducible PfCen1-GFP overexpression time-lapse in P. falciparum 3D7","pmids":["38150475"],"confidence":"High","gaps":["Whether LLPS is required for CEN1's division function in vivo was not tested by separation-of-function mutants","The physiological Ca2+ signal that triggers condensation at the plaque is not defined","How condensate dynamics couple mechanistically to spindle/centriolar plaque duplication is unresolved"],"attribution":[{"species":"Plasmodium falciparum","strain":"3D7"}]},{"year":null,"claim":"Whether CEN1 is essential in P. falciparum and how its Ca2+-dependent phase behavior mechanistically drives centriolar plaque duplication and schizont division remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No direct loss-of-function/essentiality data for CEN1 in P. falciparum","No structural model of the CEN1-PfCen3-PfSlp complex","Causal link between LLPS and division phenotype untested"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["Centriolar plaque complex containing CEN1, PfCen3, and PfSlp (PF3D7_0710000)"],"partners":["PFCEN3","PFSLP (PF3D7_0710000)"],"other_free_text":["Undergoes reversible Ca2+-dependent liquid-liquid phase separation driven by its disordered N-terminus and EF-hand motifs [#1]","Displays liquid-like condensate dynamics at the centriolar plaque timed to cell cycle progression in live parasites [#1]","Expressed in sporozoites, asexual blood forms, gametocytes, and oocysts [#0]","Episomal expression rescues growth and cytokinesis defects in a centrin-null Leishmania donovani line [#0]"]}},"prefetch_data":{},"corpus_meta":[{"pmid":"18693242","id":"PMC_18693242","title":"Centrins, cell cycle regulation proteins in human malaria parasite Plasmodium falciparum.","date":"2008","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18693242","citation_count":68,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["curated_ref"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"38150475","id":"","title":"Malaria parasite centrins can assemble by Ca2+-inducible condensation.","date":"2023","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/38150475","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CEN1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"39749880","id":"","title":"Imaging malaria parasites across scales and time.","date":"2025","source":"Journal of microscopy","url":"https://pubmed.ncbi.nlm.nih.gov/39749880","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CEN1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"37130129","id":"","title":"An Sfi1-like centrin-interacting centriolar plaque protein affects nuclear microtubule homeostasis.","date":"2023","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/37130129","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CEN1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"31882761","id":"","title":"Lyse-Reseal Erythrocytes for Transfection of Plasmodium falciparum.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31882761","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CEN1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"34946106","id":"","title":"Structural and Functional Insights into the Microtubule Organizing Centers of Toxoplasma gondii and Plasmodium spp.","date":"2021","source":"Microorganisms","url":"https://pubmed.ncbi.nlm.nih.gov/34946106","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CEN1"],"competing_organism_flag":true,"competing_organism_match":"Toxoplasma","competing_organism_only":true},{"pmid":"34830049","id":"","title":"Structural Basis for the Functional Diversity of Centrins: A Focus on Calcium Sensing Properties and Target Recognition.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/34830049","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CEN1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"24841368","id":"","title":"Identifying novel cell cycle proteins in Apicomplexa parasites through co-expression decision analysis.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24841368","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CEN1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11157,"output_tokens":1281,"usd":0.026343,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6085,"output_tokens":2237,"usd":0.043175,"stage2_stop_reason":"end_turn"},"total_usd":0.069518,"stage1_batch_id":"msgbatch_01NE1MTa8x1hW7Lo4tAaNzY1","stage2_batch_id":"msgbatch_0141vaQdeFvbo2q39AinvXM9","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2008,\n      \"finding\": \"CEN1 (PfCEN1) is expressed in sporozoites, asexual blood forms, gametocytes, and oocysts, and immunoelectron microscopy localized it in close proximity to the nucleus of sporozoites and asexual schizonts; confocal and widefield double-staining with alpha-tubulin antibodies indicated association with the parasite centrosome. Episomal expression of PfCEN1 in a centrin knock-out Leishmania donovani line partially restored growth rate and rescued a cytokinesis defect, establishing a functional role in cell division.\",\n      \"method\": \"Immunofluorescence microscopy, immunoelectron microscopy, double-staining with alpha-tubulin antibodies, growth complementation assay in centrin-KO Leishmania donovani\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization by immuno-EM and IFA tied to functional consequence via cross-species complementation, single lab with two orthogonal methods\",\n      \"pmids\": [\"18693242\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CEN1 (PfCen1) undergoes Ca2+-inducible liquid-liquid phase separation (LLPS) in vitro; recombinant PfCen1-6His formed droplets upon CaCl2 addition that dissolved upon EDTA chelation. The disordered N-terminus and calcium-binding EF-hand motifs were identified as essential features for this reversible biomolecular condensation. Live-cell STED microscopy of PfCen1-Halo in P. falciparum blood-stage parasites revealed liquid-like dynamics (wobbling droplet-like shapes and stretching/retracting structures) at the centriolar plaque. Inducible overexpression of PfCen1-GFP produced concentration-dependent extra-centrosomal condensate-like assemblies, with foci formation and dissolution timed to cell cycle progression.\",\n      \"method\": \"In vitro turbidity assay and widefield imaging of recombinant protein droplet formation; live-cell STED microscopy with HaloTag/fluorogenic dye; inducible episomal overexpression with time-lapse fluorescence microscopy\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro reconstitution of LLPS with calcium and EDTA reversal, mutagenesis-equivalent domain analysis (N-terminus/EF-hands), and orthogonal live-cell STED imaging in parasites, all in one rigorous study\",\n      \"pmids\": [\"38150475\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"3D7\"}\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CEN1 (PfCen1) localizes to the extranuclear (outer) compartment of the centriolar plaque in P. falciparum blood-stage schizonts, and co-immunoprecipitation of PfCen1-GFP followed by mass spectrometry identified PfCen3 and the Sfi1-like protein PfSlp (PF3D7_0710000) as co-precipitating partners, placing CEN1 in a complex with PfSlp at the centriolar plaque.\",\n      \"method\": \"Co-immunoprecipitation with anti-GFP antibody on episomally expressed PfCen1-GFP, followed by mass spectrometry; reciprocal IP confirmation; STED microscopy co-localization with anti-centrin antibody\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP with MS identification and STED co-localization, single lab\",\n      \"pmids\": [\"37130129\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"3D7\"}\n      ]\n    }\n  ],\n  \"current_model\": \"P. falciparum CEN1 (PfCen1/PF3D7_0107000) is a calcium-binding EF-hand protein that localizes to the extranuclear compartment of the centriolar plaque during schizogony, where it participates in cell division; it undergoes reversible Ca2+-dependent liquid-liquid phase separation driven by its disordered N-terminus and EF-hand motifs, displays liquid-like dynamics at the centriolar plaque in live parasites, and physically interacts with PfCen3 and the Sfi1-like centriolar plaque protein PfSlp.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PF3D7_0107000 (CEN1) is a calcium-binding EF-hand centrin that functions in Plasmodium falciparum cell division, localizing to the centriolar plaque during schizogony [#0, #2]. It is expressed across multiple parasite life-cycle stages (sporozoites, asexual blood forms, gametocytes, oocysts) and associates with the parasite centrosome near the nucleus, and episomal expression rescues both a growth and a cytokinesis defect in a centrin-null Leishmania donovani line, establishing a conserved role in cell division [#0]. Within blood-stage schizonts CEN1 occupies the extranuclear (outer) compartment of the centriolar plaque and physically interacts with PfCen3 and the Sfi1-like centriolar plaque protein PfSlp (PF3D7_0710000), as shown by reciprocal co-immunoprecipitation and mass spectrometry [#2]. CEN1 undergoes reversible, Ca2+-dependent liquid-liquid phase separation in vitro that is dissolved by EDTA chelation and depends on its disordered N-terminus and EF-hand motifs, and it displays liquid-like dynamics at the centriolar plaque in live parasites, with condensate formation and dissolution timed to cell cycle progression [#1]. Beyond these findings, no further mechanistic detail on CEN1 has been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Establishing whether the P. falciparum centrin CEN1 has a functional role in cell division rather than merely being a centrosome-associated protein, this work tied its centrosomal localization to a division phenotype.\",\n      \"evidence\": \"Immuno-EM and IFA co-staining with alpha-tubulin locating CEN1 to the centrosome, plus cross-species growth/cytokinesis complementation in centrin-KO Leishmania donovani\",\n      \"pmids\": [\"18693242\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Complementation was done in a heterologous Leishmania system, not by loss-of-function in P. falciparum\",\n        \"Direct molecular partners at the centrosome were not identified\",\n        \"Stage-specific functional requirements were not dissected\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"To define where CEN1 sits within the centriolar plaque and what it binds, this work resolved its extranuclear sub-compartment and identified its protein partners.\",\n      \"evidence\": \"Reciprocal anti-GFP co-immunoprecipitation of PfCen1-GFP with mass spectrometry and STED co-localization in P. falciparum 3D7 schizonts\",\n      \"pmids\": [\"37130129\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Interaction stoichiometry and directness (direct vs. bridged) with PfCen3 and PfSlp not resolved\",\n        \"Functional consequence of the CEN1-PfSlp interaction not tested by perturbation\",\n        \"Single-lab episomal-tag data without endogenous validation\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"3D7\"}\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"To explain how CEN1 organizes at the centriolar plaque, this work showed it forms reversible calcium-dependent condensates, linking its EF-hand chemistry to a biophysical assembly mechanism.\",\n      \"evidence\": \"In vitro Ca2+-induced/EDTA-reversed LLPS of recombinant PfCen1-6His with N-terminus/EF-hand domain analysis, plus live-cell STED and inducible PfCen1-GFP overexpression time-lapse in P. falciparum 3D7\",\n      \"pmids\": [\"38150475\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether LLPS is required for CEN1's division function in vivo was not tested by separation-of-function mutants\",\n        \"The physiological Ca2+ signal that triggers condensation at the plaque is not defined\",\n        \"How condensate dynamics couple mechanistically to spindle/centriolar plaque duplication is unresolved\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"3D7\"}\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Whether CEN1 is essential in P. falciparum and how its Ca2+-dependent phase behavior mechanistically drives centriolar plaque duplication and schizont division remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct loss-of-function/essentiality data for CEN1 in P. falciparum\",\n        \"No structural model of the CEN1-PfCen3-PfSlp complex\",\n        \"Causal link between LLPS and division phenotype untested\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005509\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005813\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0051301\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [\n      \"Centriolar plaque complex containing CEN1, PfCen3, and PfSlp (PF3D7_0710000)\"\n    ],\n    \"partners\": [\n      \"PfCen3\",\n      \"PfSlp (PF3D7_0710000)\"\n    ],\n    \"other_free_text\": [\n      \"Undergoes reversible Ca2+-dependent liquid-liquid phase separation driven by its disordered N-terminus and EF-hand motifs [#1]\",\n      \"Displays liquid-like condensate dynamics at the centriolar plaque timed to cell cycle progression in live parasites [#1]\",\n      \"Expressed in sporozoites, asexual blood forms, gametocytes, and oocysts [#0]\",\n      \"Episomal expression rescues growth and cytokinesis defects in a centrin-null Leishmania donovani line [#0]\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_0107000","name":null,"product":"centrin-1","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_0206300","name":null,"product":"centrin-1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_0206500","name":null,"product":"centrin-1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"CEN1","evaluation":null}