{"gene":"PF3D7_1401500","run_date":"2026-09-08T14:19:06","timeline":{"discoveries":[{"year":2017,"finding":"PfPARE (PF3D7_1401500) is a functional esterase that hydrolyses pepstatin esters and de-esterifies the antimalarial compound MMV011438 in vitro; mutations in PfPARE confer resistance to these esterified compounds by blocking prodrug activation.","method":"In vitro resistance selection with whole-genome sequencing of resistant mutants; recombinant enzyme assay demonstrating hydrolysis of pepstatin esters and MMV011438; synthesis and characterization of pepstatin ester derivatives","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — recombinant enzyme biochemical assay demonstrating catalytic activity, resistance selection with defined mutations, and chemical synthesis/pharmacological validation in a single rigorous study","pmids":["28106035"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"PfPARE (PF3D7_1401500) is required to hydrolyze the benzoxaborole prodrug AN13762 into its active metabolite AN10248; recombinant PfPARE hydrolyzed AN13762 in vitro, and introduction of PfPARE loss-of-function mutations into parasites conferred low-level resistance to AN13762 by blocking this activation step.","method":"In vitro resistance selection, whole-genome sequencing, CRISPR/genetic introduction of PfPARE mutations, recombinant enzyme hydrolysis assay","journal":"mBio","confidence":"High","confidence_rationale":"Tier 1 / Strong — recombinant enzyme assay plus genetic introduction of mutations with defined resistance phenotype, multiple independent selections, orthogonal methods in one study","pmids":["31992618"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"PfPARE (PF3D7_1401500) mediates the antimalarial potency of chlorajaponilide C (a lindenane sesquiterpenoid dimer); in vitro resistance selection yielded parasites with >250-fold increased EC50, and whole-genome sequencing revealed PfPARE mutations in all resistant clones, establishing PfPARE as required for the compound's activity. Structure-resistance relationship analysis showed that only a subset of related compounds required PfPARE activity.","method":"In vitro resistance selection, whole-genome sequencing of resistant clones, structure-activity/resistance relationship analysis across compound series","journal":"ACS infectious diseases","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — resistance selection with sequencing and SAR across multiple compounds; no recombinant enzyme assay in this study, single lab","pmids":["32970404"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"finding":"PfPARE (PF3D7_1401500) is a membrane-associated enzyme with substantial presence at the parasite periphery; it mediates low-level hydrolysis of lysophosphatidylcholine (LPC). Loss of PARE alone had no effect on fatty acid scavenging from LPC, but combined loss with XL2 and XLH4 impaired choline and fatty acid scavenging and prevented completion of a replication cycle in defined medium with LPC as sole exogenous fatty acid source.","method":"Genetic knockdown/knockout of PARE alone and in combination with XL2 and XLH4; growth assays in defined media; subcellular localization experiments","journal":"International journal for parasitology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic loss-of-function with defined metabolic phenotype and direct localization experiment; single lab, single study","pmids":["41043577"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"finding":"Characterization of the substrate structure-activity relationship of P. falciparum esterases (including PfPARE, PF3D7_1401500) using a fluorogenic ester library revealed that PfPARE has distinct substrate preferences compared to the host-derived APEH enzyme; APEH preferentially activates substrates with branching at the alpha carbon while PfPARE has a different profile.","method":"Fluorogenic ester library screening comparing recombinant/parasite esterase activities; comparative biochemical SAR analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — biochemical assay with fluorogenic substrate library establishing enzymatic substrate specificity, but PfPARE characterization is secondary to the main APEH finding in this study; single lab","pmids":["40035755"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"The pfpare locus (PF3D7_1401500) is expressed throughout the intraerythrocytic developmental cycle, is not essential for intraerythrocytic growth, and is highly conserved across P. falciparum strains, as demonstrated by successful use of the locus as an integration site for a fluorescent reporter with negligible fitness defect.","method":"CRISPR-based reporter insertion at the pfpare locus; competitive growth assays measuring fitness; fluorescence microscopy across intraerythrocytic cycle","journal":"Frontiers in cellular and infection microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct genetic manipulation with fitness assay and intraerythrocytic expression characterization; single lab but multiple orthogonal readouts","pmids":["36189342"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":"Dd2"}]}],"current_model":"PfPARE (PF3D7_1401500) is a membrane-associated P. falciparum esterase expressed throughout the intraerythrocytic cycle that functions as a prodrug-activating enzyme—hydrolyzing esterified antimalarial prodrugs (pepstatin esters, MMV011438, benzoxaborole AN13762, chlorajaponilide C) to release active compounds—and also contributes redundantly to lysophosphatidylcholine catabolism at the parasite periphery; loss-of-function mutations in PfPARE are a common mechanism of resistance to these ester prodrugs, though the gene itself is not essential for parasite replication."},"narrative":{"mechanistic_narrative":"PfPARE (PF3D7_1401500) is a functional P. falciparum esterase whose best-characterized role is the hydrolytic activation of esterified antimalarial prodrugs: recombinant enzyme de-esterifies pepstatin esters and MMV011438, and loss-of-function mutations selected in vitro block this activation to confer resistance [PMID:28106035]. This prodrug-activating function generalizes across chemically distinct scaffolds—PfPARE is required to hydrolyze the benzoxaborole AN13762 to its active metabolite AN10248 [PMID:31992618] and to unmask the antimalarial activity of the sesquiterpenoid dimer chlorajaponilide C, with PfPARE mutations recovered in all resistant clones [PMID:32970404]—establishing PfPARE loss as a recurrent, low-level resistance mechanism to ester prodrugs. Its substrate specificity is distinct from the host-derived APEH esterase [PMID:40035755]. Beyond xenobiotic hydrolysis, PfPARE is a membrane-associated enzyme concentrated at the parasite periphery that contributes redundantly to lysophosphatidylcholine catabolism: loss of PfPARE alone does not impair fatty acid scavenging, but combined loss with XL2 and XLH4 blocks choline and fatty acid scavenging from LPC [PMID:41043577]. PfPARE is expressed throughout the intraerythrocytic developmental cycle, is highly conserved across strains, and is not essential for asexual replication [PMID:36189342].","teleology":[{"year":2017,"claim":"Established PfPARE as a catalytically active esterase and defined the paradigm that its hydrolytic activity is required to unmask ester prodrugs, so its inactivation drives resistance.","evidence":"In vitro resistance selection with whole-genome sequencing, recombinant enzyme hydrolysis assays on pepstatin esters and MMV011438, and synthesis of ester derivatives","pmids":["28106035"],"confidence":"High","gaps":["No structural basis for catalysis or the active-site residues defined","Native physiological substrate not identified in this study"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"claim":"Extended the prodrug-activation role to a chemically unrelated benzoxaborole and confirmed causality by genetic introduction of the mutations, showing PfPARE-dependent activation is scaffold-general.","evidence":"In vitro resistance selection, whole-genome sequencing, CRISPR introduction of PfPARE mutations, and recombinant enzyme hydrolysis of AN13762","pmids":["31992618"],"confidence":"High","gaps":["Resistance conferred was only low-level, indicating additional activation routes exist","Kinetic parameters for AN13762 hydrolysis not reported"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"claim":"Showed PfPARE also determines the potency of a natural-product scaffold (chlorajaponilide C) but only for a subset of related compounds, refining which chemotypes depend on PfPARE.","evidence":"In vitro resistance selection, whole-genome sequencing of clones, and structure-resistance relationship analysis across a compound series","pmids":["32970404"],"confidence":"Medium","gaps":["No recombinant enzyme assay confirming direct hydrolysis of chlorajaponilide C","Chemical identity of the PfPARE-dependent step not resolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"claim":"Defined the expression, dispensability, and conservation of the locus, establishing that PfPARE is non-essential for asexual growth despite constitutive intraerythrocytic expression.","evidence":"CRISPR reporter insertion at the pfpare locus, competitive fitness assays, and fluorescence microscopy across the intraerythrocytic cycle","pmids":["36189342"],"confidence":"Medium","gaps":["Non-essentiality shown only in standard culture, not in LPC-limited conditions","Sexual-stage or in vivo requirement not assessed"],"attribution":[{"species":"Plasmodium falciparum","strain":"Dd2"}]},{"year":2025,"claim":"Assigned a native physiological function by localizing PfPARE to the parasite periphery and demonstrating its redundant contribution to lysophosphatidylcholine catabolism for lipid and choline scavenging.","evidence":"Genetic knockout of PARE alone and combined with XL2 and XLH4, growth assays in defined LPC media, and subcellular localization","pmids":["41043577"],"confidence":"Medium","gaps":["Functional redundancy prevents attributing a specific reaction to PfPARE alone","Direct enzymatic hydrolysis of LPC by recombinant PfPARE not shown"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"claim":"Distinguished PfPARE substrate specificity from the host APEH esterase, clarifying that PfPARE has its own catalytic profile relevant to prodrug design.","evidence":"Fluorogenic ester library screening and comparative biochemical structure-activity analysis of parasite versus host esterases","pmids":["40035755"],"confidence":"Medium","gaps":["PfPARE was characterized secondarily to APEH in this study","No physiological substrate mapping from the fluorogenic profile"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"The structural basis of PfPARE catalysis and the full endogenous substrate repertoire that explains its constitutive expression remain undefined.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal structure or catalytic-residue map","Native substrate beyond LPC not comprehensively identified","Contribution to drug metabolism in vivo untested"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["XL2 (FUNCTIONAL REDUNDANCY IN LPC CATABOLISM)","XLH4 (FUNCTIONAL REDUNDANCY IN LPC CATABOLISM)"],"other_free_text":["Prodrug-activating esterase: hydrolyzes pepstatin esters and MMV011438 [#0], benzoxaborole AN13762 to AN10248 [#1], and mediates chlorajaponilide C activity [#2].","Loss-of-function mutations are a recurrent mechanism of low-level resistance to these ester prodrugs [#0, #1, #2].","Substrate preference distinct from host-derived APEH esterase [#4].","Expressed throughout the intraerythrocytic developmental cycle, highly conserved across strains, and non-essential for asexual replication [#5]."]}},"prefetch_data":{},"corpus_meta":[{"pmid":"28106035","id":"PMC_28106035","title":"Esterase mutation is a mechanism of resistance to antimalarial compounds.","date":"2017","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/28106035","citation_count":53,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"6159702","id":"PMC_6159702","title":"The human materno-foetal relationship in malaria: I. Identification of pigment and parasites in the placenta.","date":"1980","source":"Transactions of the Royal Society of Tropical Medicine and Hygiene","url":"https://pubmed.ncbi.nlm.nih.gov/6159702","citation_count":48,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"28927276","id":"PMC_28927276","title":"Alkoxycarbonate Ester Prodrugs of Preclinical Drug Candidate ELQ-300 for Prophylaxis and Treatment of Malaria.","date":"2017","source":"ACS infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/28927276","citation_count":38,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"14527552","id":"PMC_14527552","title":"8-quinolinamines and their pro prodrug conjugates as potent blood-schizontocidal antimalarial agents.","date":"2003","source":"Bioorganic & medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/14527552","citation_count":31,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"31992618","id":"PMC_31992618","title":"Plasmodium falciparum Resistance to a Lead Benzoxaborole Due to Blocked Compound Activation and Altered Ubiquitination or Sumoylation.","date":"2020","source":"mBio","url":"https://pubmed.ncbi.nlm.nih.gov/31992618","citation_count":29,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"12392406","id":"PMC_12392406","title":"Synthesis and evaluation of iron chelators with masked hydrophilic moieties.","date":"2002","source":"Journal of the American Chemical Society","url":"https://pubmed.ncbi.nlm.nih.gov/12392406","citation_count":27,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"32970404","id":"PMC_32970404","title":"Resistance to Some But Not Other Dimeric Lindenane Sesquiterpenoid Esters Is Mediated by Mutations in a Plasmodium falciparum Esterase.","date":"2020","source":"ACS infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/32970404","citation_count":13,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"36189342","id":"PMC_36189342","title":"Efficient generation of mNeonGreen Plasmodium falciparum reporter lines enables quantitative fitness analysis.","date":"2022","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/36189342","citation_count":10,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"37158739","id":"PMC_37158739","title":"Susceptibility of Ugandan Plasmodium falciparum Isolates to the Antimalarial Drug Pipeline.","date":"2023","source":"Microbiology spectrum","url":"https://pubmed.ncbi.nlm.nih.gov/37158739","citation_count":8,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"40035755","id":"PMC_40035755","title":"Prodrug activation in malaria parasites mediated by an imported erythrocyte esterase, acylpeptide hydrolase (APEH).","date":"2025","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/40035755","citation_count":5,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"4104263","id":"PMC_4104263","title":"Esterase and acid phosphatases in sporogonic stages of Plasmodia.","date":"1969","source":"Acta tropica","url":"https://pubmed.ncbi.nlm.nih.gov/4104263","citation_count":5,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"38131156","id":"PMC_38131156","title":"Disruption of a Plasmodium falciparum patatin-like phospholipase delays male gametocyte exflagellation.","date":"2023","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/38131156","citation_count":3,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"38136946","id":"PMC_38136946","title":"Imidazolopiperazine (IPZ)-Induced Differential Transcriptomic Responses on Plasmodium falciparum Wild-Type and IPZ-Resistant Mutant Parasites.","date":"2023","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/38136946","citation_count":2,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"41043577","id":"PMC_41043577","title":"Defining the minimal enzymatic requirements for fatty acid scavenging from lysophosphatidylcholine by erythrocytic Plasmodium falciparum.","date":"2025","source":"International journal for parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/41043577","citation_count":1,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"39257815","id":"PMC_39257815","title":"Prodrug activation in malaria parasites mediated by an imported erythrocyte esterase, acylpeptide hydrolase (APEH).","date":"2024","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/39257815","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["esterase"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9939,"output_tokens":1851,"usd":0.028791,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6992,"output_tokens":2772,"usd":0.05213,"stage2_stop_reason":"end_turn"},"total_usd":0.080921,"stage1_batch_id":"msgbatch_011BPjN2BL33F8cJXD1r7V7T","stage2_batch_id":"msgbatch_01Qwg6vP7qxkpL6Gsc7tajsb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"PfPARE (PF3D7_1401500) is a functional esterase that hydrolyses pepstatin esters and de-esterifies the antimalarial compound MMV011438 in vitro; mutations in PfPARE confer resistance to these esterified compounds by blocking prodrug activation.\",\n      \"method\": \"In vitro resistance selection with whole-genome sequencing of resistant mutants; recombinant enzyme assay demonstrating hydrolysis of pepstatin esters and MMV011438; synthesis and characterization of pepstatin ester derivatives\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — recombinant enzyme biochemical assay demonstrating catalytic activity, resistance selection with defined mutations, and chemical synthesis/pharmacological validation in a single rigorous study\",\n      \"pmids\": [\"28106035\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PfPARE (PF3D7_1401500) is required to hydrolyze the benzoxaborole prodrug AN13762 into its active metabolite AN10248; recombinant PfPARE hydrolyzed AN13762 in vitro, and introduction of PfPARE loss-of-function mutations into parasites conferred low-level resistance to AN13762 by blocking this activation step.\",\n      \"method\": \"In vitro resistance selection, whole-genome sequencing, CRISPR/genetic introduction of PfPARE mutations, recombinant enzyme hydrolysis assay\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — recombinant enzyme assay plus genetic introduction of mutations with defined resistance phenotype, multiple independent selections, orthogonal methods in one study\",\n      \"pmids\": [\"31992618\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PfPARE (PF3D7_1401500) mediates the antimalarial potency of chlorajaponilide C (a lindenane sesquiterpenoid dimer); in vitro resistance selection yielded parasites with >250-fold increased EC50, and whole-genome sequencing revealed PfPARE mutations in all resistant clones, establishing PfPARE as required for the compound's activity. Structure-resistance relationship analysis showed that only a subset of related compounds required PfPARE activity.\",\n      \"method\": \"In vitro resistance selection, whole-genome sequencing of resistant clones, structure-activity/resistance relationship analysis across compound series\",\n      \"journal\": \"ACS infectious diseases\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — resistance selection with sequencing and SAR across multiple compounds; no recombinant enzyme assay in this study, single lab\",\n      \"pmids\": [\"32970404\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PfPARE (PF3D7_1401500) is a membrane-associated enzyme with substantial presence at the parasite periphery; it mediates low-level hydrolysis of lysophosphatidylcholine (LPC). Loss of PARE alone had no effect on fatty acid scavenging from LPC, but combined loss with XL2 and XLH4 impaired choline and fatty acid scavenging and prevented completion of a replication cycle in defined medium with LPC as sole exogenous fatty acid source.\",\n      \"method\": \"Genetic knockdown/knockout of PARE alone and in combination with XL2 and XLH4; growth assays in defined media; subcellular localization experiments\",\n      \"journal\": \"International journal for parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic loss-of-function with defined metabolic phenotype and direct localization experiment; single lab, single study\",\n      \"pmids\": [\"41043577\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Characterization of the substrate structure-activity relationship of P. falciparum esterases (including PfPARE, PF3D7_1401500) using a fluorogenic ester library revealed that PfPARE has distinct substrate preferences compared to the host-derived APEH enzyme; APEH preferentially activates substrates with branching at the alpha carbon while PfPARE has a different profile.\",\n      \"method\": \"Fluorogenic ester library screening comparing recombinant/parasite esterase activities; comparative biochemical SAR analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — biochemical assay with fluorogenic substrate library establishing enzymatic substrate specificity, but PfPARE characterization is secondary to the main APEH finding in this study; single lab\",\n      \"pmids\": [\"40035755\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The pfpare locus (PF3D7_1401500) is expressed throughout the intraerythrocytic developmental cycle, is not essential for intraerythrocytic growth, and is highly conserved across P. falciparum strains, as demonstrated by successful use of the locus as an integration site for a fluorescent reporter with negligible fitness defect.\",\n      \"method\": \"CRISPR-based reporter insertion at the pfpare locus; competitive growth assays measuring fitness; fluorescence microscopy across intraerythrocytic cycle\",\n      \"journal\": \"Frontiers in cellular and infection microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct genetic manipulation with fitness assay and intraerythrocytic expression characterization; single lab but multiple orthogonal readouts\",\n      \"pmids\": [\"36189342\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"Dd2\"}]\n    }\n  ],\n  \"current_model\": \"PfPARE (PF3D7_1401500) is a membrane-associated P. falciparum esterase expressed throughout the intraerythrocytic cycle that functions as a prodrug-activating enzyme—hydrolyzing esterified antimalarial prodrugs (pepstatin esters, MMV011438, benzoxaborole AN13762, chlorajaponilide C) to release active compounds—and also contributes redundantly to lysophosphatidylcholine catabolism at the parasite periphery; loss-of-function mutations in PfPARE are a common mechanism of resistance to these ester prodrugs, though the gene itself is not essential for parasite replication.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PfPARE (PF3D7_1401500) is a functional P. falciparum esterase whose best-characterized role is the hydrolytic activation of esterified antimalarial prodrugs: recombinant enzyme de-esterifies pepstatin esters and MMV011438, and loss-of-function mutations selected in vitro block this activation to confer resistance [#0]. This prodrug-activating function generalizes across chemically distinct scaffolds—PfPARE is required to hydrolyze the benzoxaborole AN13762 to its active metabolite AN10248 [#1] and to unmask the antimalarial activity of the sesquiterpenoid dimer chlorajaponilide C, with PfPARE mutations recovered in all resistant clones [#2]—establishing PfPARE loss as a recurrent, low-level resistance mechanism to ester prodrugs. Its substrate specificity is distinct from the host-derived APEH esterase [#4]. Beyond xenobiotic hydrolysis, PfPARE is a membrane-associated enzyme concentrated at the parasite periphery that contributes redundantly to lysophosphatidylcholine catabolism: loss of PfPARE alone does not impair fatty acid scavenging, but combined loss with XL2 and XLH4 blocks choline and fatty acid scavenging from LPC [#3]. PfPARE is expressed throughout the intraerythrocytic developmental cycle, is highly conserved across strains, and is not essential for asexual replication [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Established PfPARE as a catalytically active esterase and defined the paradigm that its hydrolytic activity is required to unmask ester prodrugs, so its inactivation drives resistance.\",\n      \"evidence\": \"In vitro resistance selection with whole-genome sequencing, recombinant enzyme hydrolysis assays on pepstatin esters and MMV011438, and synthesis of ester derivatives\",\n      \"pmids\": [\"28106035\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural basis for catalysis or the active-site residues defined\", \"Native physiological substrate not identified in this study\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended the prodrug-activation role to a chemically unrelated benzoxaborole and confirmed causality by genetic introduction of the mutations, showing PfPARE-dependent activation is scaffold-general.\",\n      \"evidence\": \"In vitro resistance selection, whole-genome sequencing, CRISPR introduction of PfPARE mutations, and recombinant enzyme hydrolysis of AN13762\",\n      \"pmids\": [\"31992618\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Resistance conferred was only low-level, indicating additional activation routes exist\", \"Kinetic parameters for AN13762 hydrolysis not reported\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed PfPARE also determines the potency of a natural-product scaffold (chlorajaponilide C) but only for a subset of related compounds, refining which chemotypes depend on PfPARE.\",\n      \"evidence\": \"In vitro resistance selection, whole-genome sequencing of clones, and structure-resistance relationship analysis across a compound series\",\n      \"pmids\": [\"32970404\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No recombinant enzyme assay confirming direct hydrolysis of chlorajaponilide C\", \"Chemical identity of the PfPARE-dependent step not resolved\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined the expression, dispensability, and conservation of the locus, establishing that PfPARE is non-essential for asexual growth despite constitutive intraerythrocytic expression.\",\n      \"evidence\": \"CRISPR reporter insertion at the pfpare locus, competitive fitness assays, and fluorescence microscopy across the intraerythrocytic cycle\",\n      \"pmids\": [\"36189342\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Non-essentiality shown only in standard culture, not in LPC-limited conditions\", \"Sexual-stage or in vivo requirement not assessed\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"Dd2\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Assigned a native physiological function by localizing PfPARE to the parasite periphery and demonstrating its redundant contribution to lysophosphatidylcholine catabolism for lipid and choline scavenging.\",\n      \"evidence\": \"Genetic knockout of PARE alone and combined with XL2 and XLH4, growth assays in defined LPC media, and subcellular localization\",\n      \"pmids\": [\"41043577\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional redundancy prevents attributing a specific reaction to PfPARE alone\", \"Direct enzymatic hydrolysis of LPC by recombinant PfPARE not shown\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Distinguished PfPARE substrate specificity from the host APEH esterase, clarifying that PfPARE has its own catalytic profile relevant to prodrug design.\",\n      \"evidence\": \"Fluorogenic ester library screening and comparative biochemical structure-activity analysis of parasite versus host esterases\",\n      \"pmids\": [\"40035755\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"PfPARE was characterized secondarily to APEH in this study\", \"No physiological substrate mapping from the fluorogenic profile\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of PfPARE catalysis and the full endogenous substrate repertoire that explains its constitutive expression remain undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal structure or catalytic-residue map\", \"Native substrate beyond LPC not comprehensively identified\", \"Contribution to drug metabolism in vivo untested\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0052689\", \"supporting_discovery_ids\": [0, 1, 4]},\n      {\"term_id\": \"GO:0016298\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0016020\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0046471\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"XL2 (functional redundancy in LPC catabolism)\", \"XLH4 (functional redundancy in LPC catabolism)\"],\n    \"other_free_text\": [\n      \"Prodrug-activating esterase: hydrolyzes pepstatin esters and MMV011438 [#0], benzoxaborole AN13762 to AN10248 [#1], and mediates chlorajaponilide C activity [#2].\",\n      \"Loss-of-function mutations are a recurrent mechanism of low-level resistance to these ester prodrugs [#0, #1, #2].\",\n      \"Substrate preference distinct from host-derived APEH esterase [#4].\",\n      \"Expressed throughout the intraerythrocytic developmental cycle, highly conserved across strains, and non-essential for asexual replication [#5].\"\n    ]\n  }\n}","audit_flag":{"gene":"PF3D7_1401500","tier":"IDENTITY_CHECK","verdict":"identity unverified","subtype":"names_other_cards","uniprot_band":"","rules_fired":"R12","issue":"No cited paper names this card; 4 of 6 cited papers name other catalogue genes (PF3D7_0709700, PF3D7_1438500, PF3D7_1001600). The summary may describe one of those genes."},"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_1401500","name":null,"product":"esterase, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"","evaluation":null}