{"gene":"PF3D7_0702900","run_date":"2026-09-08T12:51:27","timeline":{"discoveries":[{"year":2008,"finding":"P. falciparum possesses four centrin paralogs (PfCENs) with four Ca2+-binding EF-hand domains; immunoelectron microscopy showed centrin protein is expressed in close proximity to the nucleus of sporozoites and asexual schizonts, and confocal/widefield microscopy with double-staining (anti-α-tubulin and anti-centrin) indicated association with the parasite centrosome. Episomal expression of PfCENs in a centrin-knockout Leishmania donovani line (growth complementation assay) showed that one PfCEN partially restored growth rate and overcame a cytokinesis defect, providing evidence for centrin involvement in cell division.","method":"Immunoelectron microscopy, immunofluorescence microscopy (double-staining with α-tubulin), growth complementation in centrin-KO Leishmania donovani, real-time PCR","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — multiple orthogonal methods (IEM, IFA, functional complementation in heterologous system), single lab; complementation is an indirect proxy for P. falciparum function","pmids":["18693242"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2021,"finding":"Super-resolution and correlative light/electron tomography revealed that centrin is confined to the extranuclear compartment of the centriolar plaque (the centrosome of P. falciparum), while microtubules are nucleated in a separate, previously unknown extended intranuclear, chromatin-free, protein-dense compartment. This established two distinct spatial compartments of the centriolar plaque and showed centrin does not co-localize with intranuclear spindle microtubules.","method":"Super-resolution microscopy (STED/SIM), time-lapse imaging, correlative light and electron tomography","journal":"Life science alliance","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal high-resolution imaging methods (super-resolution fluorescence + correlative electron tomography) establishing spatial compartmentalization with structural validation","pmids":["34535568"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2019,"finding":"In P. berghei, a centrin (PbCEN-4, an alveolate-specific centrin orthologous to one of the PfCENs) localizes to the putative MTOC during asexual replicative stages as shown by live-cell imaging, forms a multi-protein complex with other centrins, but is dispensable for parasite proliferation (gene deletion had no detectable growth defect).","method":"Live-cell imaging (GFP-tagging), gene deletion (knockout), co-immunoprecipitation/complex analysis","journal":"Biology open","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — live-cell imaging and genetic KO with proliferation readout, single lab; PbCEN-4 is the P. berghei alveolate-specific centrin, ortholog of one of the four PfCENs","pmids":["30541825"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2022,"finding":"In P. berghei microgametocytes, centrin (along with γ-tubulin, SAS4, and SAS6) forms distinct subdomains within de novo assembled basal bodies in a SAS6- and SAS4-dependent manner from a deuterosome-like structure. Ultrastructure expansion microscopy (U-ExM/Pan-ExM) revealed centrin and SAS6 are surrounded by a SAS4-toroid in the lumen of the microtubule wall at basal bodies, placing centrin at the cytoplasmic basal body component of the bipartite MTOC that coordinates axoneme assembly with mitosis.","method":"Ultrastructure expansion microscopy (U-ExM, Pan-ExM), 3D reconstruction, immunofluorescence","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — high-resolution expansion microscopy with 3D reconstruction and multiple molecular markers providing structural-level spatial resolution in two species","pmids":["35077503"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2023,"finding":"Multiple P. falciparum centrins (including those at the centriolar plaque) undergo Ca2+-inducible liquid-liquid phase separation (LLPS) in vitro. The disordered N-terminus and Ca2+-binding EF-hand motifs are essential features for reversible biomolecular condensation. Certain centrins form co-condensates with each other. In vivo, live-cell STED microscopy revealed liquid-like dynamics of centrosomal centrin, and an inducible overexpression system showed concentration-dependent formation of extra-centrosomal centrin assemblies with condensate-like properties; timing of foci formation/dissolution suggests regulated assembly.","method":"In vitro LLPS assay, mutagenesis (N-terminus deletion, EF-hand mutations), live-cell STED microscopy, inducible protein overexpression system","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — in vitro reconstitution of phase separation with mutagenesis, combined with in vivo live-cell super-resolution imaging and orthogonal overexpression validation, single lab but multiple orthogonal methods","pmids":["38150475"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2023,"finding":"A novel Sfi1-like centriolar plaque protein (PfSlp) was identified as a centrin-interacting protein residing in the extranuclear compartment of the centriolar plaque; conditional knockdown of PfSlp caused growth delay and reduced daughter cell number, increased intranuclear tubulin abundance, and produced excess microtubules and aberrant mitotic spindles—establishing a functional link between the extranuclear centrin-containing compartment and intranuclear tubulin homeostasis.","method":"Co-immunoprecipitation/protein interaction assay, conditional knockdown, immunofluorescence microscopy, time-lapse microscopy","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — centrin's role is inferred through its interaction with PfSlp and co-localization; the functional consequences come from PfSlp KD, not direct centrin manipulation; single lab","pmids":["37130129"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2024,"finding":"EF-hand-containing P. falciparum Centrin 2 (PF3D7_0702900) partially localizes to the posterior cup subcompartment of the basal complex (in addition to its centrosomal localization), is essential for parasite growth and replication, and its perturbation causes variable defects in basal complex contraction and synchrony. Free intracellular calcium was shown to be necessary but not sufficient for basal complex contraction.","method":"Ultrastructure expansion microscopy (U-ExM), live-cell microscopy, conditional knockdown/loss-of-function, calcium manipulation assays","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — U-ExM localization plus conditional knockdown with defined cellular phenotype (basal complex contraction defect), single lab, multiple orthogonal methods","pmids":["38829893"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"Depletion of PfMCMBP in P. falciparum led to abnormal centrin distribution (by immunofluorescence) alongside aberrant mitotic spindle formation, demonstrating that centrin localization at the centriolar plaque is sensitive to disruption of nuclear division regulators. (Note: this is an indirect observation of centrin behavior consequent to PfMCMBP depletion, not a direct manipulation of centrin.)","method":"Conditional depletion (PfMCMBP), immunofluorescence microscopy","journal":"Cellular microbiology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — centrin distribution was an ancillary readout in a study of a different protein; single observation, no direct centrin manipulation","pmids":["33124706"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"P. falciparum Centrin 2 (PF3D7_0702900) is a Ca2+-binding EF-hand protein that resides in the extranuclear compartment of the centriolar plaque (centrosome), where it assembles via Ca2+-inducible liquid-liquid phase separation dependent on its disordered N-terminus and EF-hand motifs; it also partially localizes to the posterior cup of the basal complex, is essential for parasite growth and replication, and its perturbation disrupts basal complex contraction and synchrony during cytokinesis."},"narrative":{"mechanistic_narrative":"PF3D7_0702900 (centrin 2) is a Ca2+-binding EF-hand protein of the P. falciparum centriolar plaque (the parasite centrosome) that functions in the coordination of nuclear division and daughter-cell formation during schizogony [PMID:18693242, PMID:34535568]. High-resolution and correlative imaging place it in the extranuclear compartment of the centriolar plaque, spatially distinct from the intranuclear microtubule-nucleating compartment and its spindle microtubules [PMID:34535568]. Within this compartment it assembles through Ca2+-inducible liquid-liquid phase separation that depends on its disordered N-terminus and its Ca2+-binding EF-hand motifs; centrin condensates are dynamic and liquid-like in living parasites, and their concentration-dependent, regulated assembly and dissolution provide a mechanism for organizing the centriolar plaque [PMID:38150475]. Beyond the centrosome, centrin 2 partially localizes to the posterior cup of the basal complex and is essential for parasite growth and replication, with its perturbation disrupting basal complex contraction and division synchrony; free intracellular calcium is necessary but not sufficient for this contraction [PMID:38829893]. Centrin function connects to intranuclear tubulin homeostasis through its extranuclear interaction partner PfSlp, whose loss deregulates spindle microtubule abundance [PMID:37130129].","teleology":[{"year":2008,"claim":"Establishing whether P. falciparum encodes centrins and whether they participate in cell division answered the basic question of centrin's existence and functional relevance in this parasite.","evidence":"Immunoelectron and immunofluorescence microscopy localizing centrin near the nucleus/centrosome, plus growth complementation of a centrin-KO Leishmania donovani line by an episomal PfCEN","pmids":["18693242"],"confidence":"Medium","gaps":["Complementation in a heterologous system is an indirect proxy for the native P. falciparum role","Did not distinguish the four paralogs or assign function specifically to PF3D7_0702900","No direct loss-of-function in P. falciparum"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2019,"claim":"Testing whether an alveolate-specific centrin is required for proliferation addressed whether centrin function is essential, revealing dispensability in a rodent-malaria ortholog.","evidence":"Live-cell GFP imaging, gene deletion with proliferation readout, and complex analysis of PbCEN-4 in P. berghei","pmids":["30541825"],"confidence":"Medium","gaps":["Findings are for the P. berghei ortholog PbCEN-4, not PF3D7_0702900 itself","MTOC localization is 'putative'","Dispensability may not transfer to the P. falciparum paralog"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2021,"claim":"Resolving where centrin sits within the centriolar plaque answered whether centrin nucleates spindle microtubules, showing it occupies a compartment separate from the intranuclear microtubule-organizing region.","evidence":"Super-resolution microscopy and correlative light/electron tomography of the P. falciparum centriolar plaque","pmids":["34535568"],"confidence":"High","gaps":["Structural compartmentalization does not define centrin's molecular activity","Does not identify what recruits centrin to the extranuclear compartment"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"claim":"Mapping centrin within de novo basal bodies in microgametocytes addressed how the parasite builds its bipartite MTOC, placing centrin at the cytoplasmic basal body component that coordinates axoneme assembly with mitosis.","evidence":"Ultrastructure expansion microscopy (U-ExM/Pan-ExM) with 3D reconstruction, showing centrin/SAS6 enclosed by a SAS4-toroid in a SAS6/SAS4-dependent manner","pmids":["35077503"],"confidence":"High","gaps":["Assembly context is gametocyte basal bodies, distinct from asexual centriolar plaque","Does not establish a functional requirement for centrin in basal body formation"],"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2023,"claim":"Determining the biophysical basis of centriolar plaque assembly answered how centrin organizes at the centrosome, identifying Ca2+-inducible liquid-liquid phase separation driven by the disordered N-terminus and EF-hand motifs.","evidence":"In vitro LLPS reconstitution with N-terminus/EF-hand mutagenesis, live-cell STED, and inducible overexpression producing condensate-like assemblies in P. falciparum","pmids":["38150475"],"confidence":"High","gaps":["Does not resolve which cellular Ca2+ signals trigger physiological condensation","Co-condensation partners among centrins not fully mapped for PF3D7_0702900 specifically"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2023,"claim":"Identifying a centrin-interacting Sfi1-like protein connected the extranuclear centrin compartment to intranuclear tubulin homeostasis, showing this compartment regulates spindle microtubule abundance.","evidence":"Co-immunoprecipitation identifying PfSlp, plus conditional PfSlp knockdown causing excess microtubules and aberrant spindles in P. falciparum","pmids":["37130129"],"confidence":"Medium","gaps":["Phenotypes derive from PfSlp knockdown, not direct centrin manipulation","Mechanism by which the extranuclear compartment controls intranuclear tubulin is unresolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2024,"claim":"Direct loss-of-function of PF3D7_0702900 answered whether it is essential and where else it acts, establishing an additional basal complex localization and a role in contraction and division synchrony.","evidence":"U-ExM localization, live-cell microscopy, conditional knockdown, and calcium manipulation in P. falciparum","pmids":["38829893"],"confidence":"Medium","gaps":["Basal complex contraction defects were variable","Molecular mechanism linking centrin to contraction is not defined","How its centrosomal versus basal complex functions are partitioned is unclear"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"claim":"Observing abnormal centrin distribution upon PfMCMBP depletion indicated that centrin positioning depends on the integrity of nuclear division regulators.","evidence":"Conditional depletion of PfMCMBP with immunofluorescence readout of centrin in P. falciparum","pmids":["33124706"],"confidence":"Low","gaps":["Ancillary readout in a study of a different protein, not direct centrin manipulation","Single observation without orthogonal confirmation","No mechanistic link between PfMCMBP and centrin established"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"The molecular activity of centrin 2 at the basal complex and how its Ca2+-responsive condensation is translated into force generation or contraction remain open.","evidence":"","pmids":[],"confidence":"Low","gaps":["No defined molecular effector coupling centrin to basal complex contraction","How Ca2+ signals are timed relative to condensation in vivo is unknown","Functional distinction among the four PfCEN paralogs at each site not resolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["Centriolar plaque (extranuclear compartment)","Basal body (centrin/SAS6 core enclosed by SAS4-toroid, in gametocytes)","Multi-centrin complex (P. berghei PbCEN-4)"],"partners":["PFSLP (SFI1-LIKE CENTRIOLAR PLAQUE PROTEIN)","OTHER P. FALCIPARUM CENTRINS (CO-CONDENSATION)"],"other_free_text":["Assembles via Ca2+-inducible liquid-liquid phase separation dependent on its disordered N-terminus and EF-hand motifs","Partially localizes to the posterior cup of the basal complex; essential for growth and replication; perturbation disrupts basal complex contraction and division synchrony","Free intracellular calcium is necessary but not sufficient for basal complex contraction","P. berghei ortholog PbCEN-4 is dispensable for proliferation, in contrast to the essentiality shown for P. falciparum PF3D7_0702900","Centrin distribution is sensitive to depletion of nuclear division regulators (PfMCMBP) — low-confidence, indirect"]}},"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":67,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"34535568","id":"PMC_34535568","title":"An extended DNA-free intranuclear compartment organizes centrosome microtubules in malaria parasites.","date":"2021","source":"Life science alliance","url":"https://pubmed.ncbi.nlm.nih.gov/34535568","citation_count":56,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"35077503","id":"PMC_35077503","title":"Expansion microscopy of Plasmodium gametocytes reveals the molecular architecture of a bipartite microtubule organisation centre coordinating mitosis with axoneme assembly.","date":"2022","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/35077503","citation_count":52,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"30541825","id":"PMC_30541825","title":"Plasmodium centrin PbCEN-4 localizes to the putative MTOC and is dispensable for malaria parasite proliferation.","date":"2019","source":"Biology open","url":"https://pubmed.ncbi.nlm.nih.gov/30541825","citation_count":24,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"33154955","id":"PMC_33154955","title":"Plasmodium berghei Kinesin-5 Associates With the Spindle Apparatus During Cell Division and Is Important for Efficient Production of Infectious Sporozoites.","date":"2020","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/33154955","citation_count":18,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"33124706","id":"PMC_33124706","title":"Depletion of the mini-chromosome maintenance complex binding protein allows the progression of cytokinesis despite abnormal karyokinesis during the asexual development of Plasmodium falciparum.","date":"2020","source":"Cellular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/33124706","citation_count":15,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"38150475","id":"PMC_38150475","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":11,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"37130129","id":"PMC_37130129","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":7,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"38829893","id":"PMC_38829893","title":"Elucidating the spatio-temporal dynamics of the Plasmodium falciparum basal complex.","date":"2024","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/38829893","citation_count":3,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["centrin"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7198,"output_tokens":2674,"usd":0.030852,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8097,"output_tokens":3643,"usd":0.06578,"stage2_stop_reason":"end_turn"},"total_usd":0.096632,"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\": 2008,\n      \"finding\": \"P. falciparum possesses four centrin paralogs (PfCENs) with four Ca2+-binding EF-hand domains; immunoelectron microscopy showed centrin protein is expressed in close proximity to the nucleus of sporozoites and asexual schizonts, and confocal/widefield microscopy with double-staining (anti-α-tubulin and anti-centrin) indicated association with the parasite centrosome. Episomal expression of PfCENs in a centrin-knockout Leishmania donovani line (growth complementation assay) showed that one PfCEN partially restored growth rate and overcame a cytokinesis defect, providing evidence for centrin involvement in cell division.\",\n      \"method\": \"Immunoelectron microscopy, immunofluorescence microscopy (double-staining with α-tubulin), growth complementation in centrin-KO Leishmania donovani, real-time PCR\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — multiple orthogonal methods (IEM, IFA, functional complementation in heterologous system), single lab; complementation is an indirect proxy for P. falciparum function\",\n      \"pmids\": [\"18693242\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Super-resolution and correlative light/electron tomography revealed that centrin is confined to the extranuclear compartment of the centriolar plaque (the centrosome of P. falciparum), while microtubules are nucleated in a separate, previously unknown extended intranuclear, chromatin-free, protein-dense compartment. This established two distinct spatial compartments of the centriolar plaque and showed centrin does not co-localize with intranuclear spindle microtubules.\",\n      \"method\": \"Super-resolution microscopy (STED/SIM), time-lapse imaging, correlative light and electron tomography\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal high-resolution imaging methods (super-resolution fluorescence + correlative electron tomography) establishing spatial compartmentalization with structural validation\",\n      \"pmids\": [\"34535568\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In P. berghei, a centrin (PbCEN-4, an alveolate-specific centrin orthologous to one of the PfCENs) localizes to the putative MTOC during asexual replicative stages as shown by live-cell imaging, forms a multi-protein complex with other centrins, but is dispensable for parasite proliferation (gene deletion had no detectable growth defect).\",\n      \"method\": \"Live-cell imaging (GFP-tagging), gene deletion (knockout), co-immunoprecipitation/complex analysis\",\n      \"journal\": \"Biology open\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — live-cell imaging and genetic KO with proliferation readout, single lab; PbCEN-4 is the P. berghei alveolate-specific centrin, ortholog of one of the four PfCENs\",\n      \"pmids\": [\"30541825\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"In P. berghei microgametocytes, centrin (along with γ-tubulin, SAS4, and SAS6) forms distinct subdomains within de novo assembled basal bodies in a SAS6- and SAS4-dependent manner from a deuterosome-like structure. Ultrastructure expansion microscopy (U-ExM/Pan-ExM) revealed centrin and SAS6 are surrounded by a SAS4-toroid in the lumen of the microtubule wall at basal bodies, placing centrin at the cytoplasmic basal body component of the bipartite MTOC that coordinates axoneme assembly with mitosis.\",\n      \"method\": \"Ultrastructure expansion microscopy (U-ExM, Pan-ExM), 3D reconstruction, immunofluorescence\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — high-resolution expansion microscopy with 3D reconstruction and multiple molecular markers providing structural-level spatial resolution in two species\",\n      \"pmids\": [\"35077503\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Multiple P. falciparum centrins (including those at the centriolar plaque) undergo Ca2+-inducible liquid-liquid phase separation (LLPS) in vitro. The disordered N-terminus and Ca2+-binding EF-hand motifs are essential features for reversible biomolecular condensation. Certain centrins form co-condensates with each other. In vivo, live-cell STED microscopy revealed liquid-like dynamics of centrosomal centrin, and an inducible overexpression system showed concentration-dependent formation of extra-centrosomal centrin assemblies with condensate-like properties; timing of foci formation/dissolution suggests regulated assembly.\",\n      \"method\": \"In vitro LLPS assay, mutagenesis (N-terminus deletion, EF-hand mutations), live-cell STED microscopy, inducible protein overexpression system\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — in vitro reconstitution of phase separation with mutagenesis, combined with in vivo live-cell super-resolution imaging and orthogonal overexpression validation, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"38150475\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"A novel Sfi1-like centriolar plaque protein (PfSlp) was identified as a centrin-interacting protein residing in the extranuclear compartment of the centriolar plaque; conditional knockdown of PfSlp caused growth delay and reduced daughter cell number, increased intranuclear tubulin abundance, and produced excess microtubules and aberrant mitotic spindles—establishing a functional link between the extranuclear centrin-containing compartment and intranuclear tubulin homeostasis.\",\n      \"method\": \"Co-immunoprecipitation/protein interaction assay, conditional knockdown, immunofluorescence microscopy, time-lapse microscopy\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — centrin's role is inferred through its interaction with PfSlp and co-localization; the functional consequences come from PfSlp KD, not direct centrin manipulation; single lab\",\n      \"pmids\": [\"37130129\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"EF-hand-containing P. falciparum Centrin 2 (PF3D7_0702900) partially localizes to the posterior cup subcompartment of the basal complex (in addition to its centrosomal localization), is essential for parasite growth and replication, and its perturbation causes variable defects in basal complex contraction and synchrony. Free intracellular calcium was shown to be necessary but not sufficient for basal complex contraction.\",\n      \"method\": \"Ultrastructure expansion microscopy (U-ExM), live-cell microscopy, conditional knockdown/loss-of-function, calcium manipulation assays\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — U-ExM localization plus conditional knockdown with defined cellular phenotype (basal complex contraction defect), single lab, multiple orthogonal methods\",\n      \"pmids\": [\"38829893\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Depletion of PfMCMBP in P. falciparum led to abnormal centrin distribution (by immunofluorescence) alongside aberrant mitotic spindle formation, demonstrating that centrin localization at the centriolar plaque is sensitive to disruption of nuclear division regulators. (Note: this is an indirect observation of centrin behavior consequent to PfMCMBP depletion, not a direct manipulation of centrin.)\",\n      \"method\": \"Conditional depletion (PfMCMBP), immunofluorescence microscopy\",\n      \"journal\": \"Cellular microbiology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — centrin distribution was an ancillary readout in a study of a different protein; single observation, no direct centrin manipulation\",\n      \"pmids\": [\"33124706\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"P. falciparum Centrin 2 (PF3D7_0702900) is a Ca2+-binding EF-hand protein that resides in the extranuclear compartment of the centriolar plaque (centrosome), where it assembles via Ca2+-inducible liquid-liquid phase separation dependent on its disordered N-terminus and EF-hand motifs; it also partially localizes to the posterior cup of the basal complex, is essential for parasite growth and replication, and its perturbation disrupts basal complex contraction and synchrony during cytokinesis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PF3D7_0702900 (centrin 2) is a Ca2+-binding EF-hand protein of the P. falciparum centriolar plaque (the parasite centrosome) that functions in the coordination of nuclear division and daughter-cell formation during schizogony [#0, #1]. High-resolution and correlative imaging place it in the extranuclear compartment of the centriolar plaque, spatially distinct from the intranuclear microtubule-nucleating compartment and its spindle microtubules [#1]. Within this compartment it assembles through Ca2+-inducible liquid-liquid phase separation that depends on its disordered N-terminus and its Ca2+-binding EF-hand motifs; centrin condensates are dynamic and liquid-like in living parasites, and their concentration-dependent, regulated assembly and dissolution provide a mechanism for organizing the centriolar plaque [#4]. Beyond the centrosome, centrin 2 partially localizes to the posterior cup of the basal complex and is essential for parasite growth and replication, with its perturbation disrupting basal complex contraction and division synchrony; free intracellular calcium is necessary but not sufficient for this contraction [#6]. Centrin function connects to intranuclear tubulin homeostasis through its extranuclear interaction partner PfSlp, whose loss deregulates spindle microtubule abundance [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Establishing whether P. falciparum encodes centrins and whether they participate in cell division answered the basic question of centrin's existence and functional relevance in this parasite.\",\n      \"evidence\": \"Immunoelectron and immunofluorescence microscopy localizing centrin near the nucleus/centrosome, plus growth complementation of a centrin-KO Leishmania donovani line by an episomal PfCEN\",\n      \"pmids\": [\"18693242\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Complementation in a heterologous system is an indirect proxy for the native P. falciparum role\", \"Did not distinguish the four paralogs or assign function specifically to PF3D7_0702900\", \"No direct loss-of-function in P. falciparum\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Testing whether an alveolate-specific centrin is required for proliferation addressed whether centrin function is essential, revealing dispensability in a rodent-malaria ortholog.\",\n      \"evidence\": \"Live-cell GFP imaging, gene deletion with proliferation readout, and complex analysis of PbCEN-4 in P. berghei\",\n      \"pmids\": [\"30541825\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Findings are for the P. berghei ortholog PbCEN-4, not PF3D7_0702900 itself\", \"MTOC localization is 'putative'\", \"Dispensability may not transfer to the P. falciparum paralog\"],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Resolving where centrin sits within the centriolar plaque answered whether centrin nucleates spindle microtubules, showing it occupies a compartment separate from the intranuclear microtubule-organizing region.\",\n      \"evidence\": \"Super-resolution microscopy and correlative light/electron tomography of the P. falciparum centriolar plaque\",\n      \"pmids\": [\"34535568\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural compartmentalization does not define centrin's molecular activity\", \"Does not identify what recruits centrin to the extranuclear compartment\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Mapping centrin within de novo basal bodies in microgametocytes addressed how the parasite builds its bipartite MTOC, placing centrin at the cytoplasmic basal body component that coordinates axoneme assembly with mitosis.\",\n      \"evidence\": \"Ultrastructure expansion microscopy (U-ExM/Pan-ExM) with 3D reconstruction, showing centrin/SAS6 enclosed by a SAS4-toroid in a SAS6/SAS4-dependent manner\",\n      \"pmids\": [\"35077503\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Assembly context is gametocyte basal bodies, distinct from asexual centriolar plaque\", \"Does not establish a functional requirement for centrin in basal body formation\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}, {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Determining the biophysical basis of centriolar plaque assembly answered how centrin organizes at the centrosome, identifying Ca2+-inducible liquid-liquid phase separation driven by the disordered N-terminus and EF-hand motifs.\",\n      \"evidence\": \"In vitro LLPS reconstitution with N-terminus/EF-hand mutagenesis, live-cell STED, and inducible overexpression producing condensate-like assemblies in P. falciparum\",\n      \"pmids\": [\"38150475\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not resolve which cellular Ca2+ signals trigger physiological condensation\", \"Co-condensation partners among centrins not fully mapped for PF3D7_0702900 specifically\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identifying a centrin-interacting Sfi1-like protein connected the extranuclear centrin compartment to intranuclear tubulin homeostasis, showing this compartment regulates spindle microtubule abundance.\",\n      \"evidence\": \"Co-immunoprecipitation identifying PfSlp, plus conditional PfSlp knockdown causing excess microtubules and aberrant spindles in P. falciparum\",\n      \"pmids\": [\"37130129\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Phenotypes derive from PfSlp knockdown, not direct centrin manipulation\", \"Mechanism by which the extranuclear compartment controls intranuclear tubulin is unresolved\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Direct loss-of-function of PF3D7_0702900 answered whether it is essential and where else it acts, establishing an additional basal complex localization and a role in contraction and division synchrony.\",\n      \"evidence\": \"U-ExM localization, live-cell microscopy, conditional knockdown, and calcium manipulation in P. falciparum\",\n      \"pmids\": [\"38829893\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Basal complex contraction defects were variable\", \"Molecular mechanism linking centrin to contraction is not defined\", \"How its centrosomal versus basal complex functions are partitioned is unclear\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Observing abnormal centrin distribution upon PfMCMBP depletion indicated that centrin positioning depends on the integrity of nuclear division regulators.\",\n      \"evidence\": \"Conditional depletion of PfMCMBP with immunofluorescence readout of centrin in P. falciparum\",\n      \"pmids\": [\"33124706\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Ancillary readout in a study of a different protein, not direct centrin manipulation\", \"Single observation without orthogonal confirmation\", \"No mechanistic link between PfMCMBP and centrin established\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular activity of centrin 2 at the basal complex and how its Ca2+-responsive condensation is translated into force generation or contraction remain open.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No defined molecular effector coupling centrin to basal complex contraction\", \"How Ca2+ signals are timed relative to condensation in vivo is unknown\", \"Functional distinction among the four PfCEN paralogs at each site not resolved\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005509\", \"supporting_discovery_ids\": [0, 4, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005813\", \"supporting_discovery_ids\": [0, 1, 4]},\n      {\"term_id\": \"GO:0036064\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0051301\", \"supporting_discovery_ids\": [0, 6]},\n      {\"term_id\": \"GO:0000278\", \"supporting_discovery_ids\": [1, 5, 7]}\n    ],\n    \"complexes\": [\n      \"Centriolar plaque (extranuclear compartment)\",\n      \"Basal body (centrin/SAS6 core enclosed by SAS4-toroid, in gametocytes)\",\n      \"Multi-centrin complex (P. berghei PbCEN-4)\"\n    ],\n    \"partners\": [\n      \"PfSlp (Sfi1-like centriolar plaque protein)\",\n      \"Other P. falciparum centrins (co-condensation)\"\n    ],\n    \"other_free_text\": [\n      \"Assembles via Ca2+-inducible liquid-liquid phase separation dependent on its disordered N-terminus and EF-hand motifs\",\n      \"Partially localizes to the posterior cup of the basal complex; essential for growth and replication; perturbation disrupts basal complex contraction and division synchrony\",\n      \"Free intracellular calcium is necessary but not sufficient for basal complex contraction\",\n      \"P. berghei ortholog PbCEN-4 is dispensable for proliferation, in contrast to the essentiality shown for P. falciparum PF3D7_0702900\",\n      \"Centrin distribution is sensitive to depletion of nuclear division regulators (PfMCMBP) — low-confidence, indirect\"\n    ]\n  }\n}","audit_flag":{"gene":"PF3D7_0702900","tier":"IDENTITY_CHECK","verdict":"identity unverified","subtype":"names_other_cards","uniprot_band":"","rules_fired":"R12","issue":"No cited paper names this card; 4 of 8 cited papers name other catalogue genes (PF3D7_0607600, PF3D7_1458500, PF3D7_1105500). The summary may describe one of those genes."},"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_0702900","name":null,"product":"centrin, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_0800600","name":null,"product":"centrin, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_0101100","name":null,"product":"centrin, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"","evaluation":null}