{"gene":"PF3D7_1252600","run_date":"2026-09-08T14:19:06","timeline":{"discoveries":[{"year":2017,"finding":"PfPARE (PF3D7_1252600) is a functional esterase required for activation of esterified pepstatin prodrugs and MMV011438; recombinant PfPARE hydrolyses pepstatin esters and de-esterifies MMV011438 in vitro, and mutations in PfPARE confer resistance to these compounds.","method":"Resistant mutant selection, whole-genome sequencing, recombinant protein enzymatic assay (in vitro hydrolysis), synthesis of derivatives","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — recombinant protein in vitro enzymatic assay combined with resistance selection and mutagenesis, establishing catalytic mechanism and prodrug activation role","pmids":["28106035"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"PfPARE (PF3D7_1252600) activates the benzoxaborole AN13762 by hydrolyzing it to AN10248; mutations in PfPARE prevent this processing and confer low-level resistance to AN13762, establishing PfPARE-mediated prodrug activation as a resistance mechanism.","method":"In vitro resistance selection, whole-genome sequencing, introduction of PfPARE mutations by genetic engineering, recombinant PfPARE enzymatic assay","journal":"mBio","confidence":"High","confidence_rationale":"Tier 1 / Strong — recombinant enzyme assay plus introduction of specific mutations confirmed loss of activation, replicated the mechanism from PMID:28106035","pmids":["31992618"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"PfPARE (PF3D7_1252600) mediates the in vitro potency of chlorajaponilide C (a lindenane sesquiterpenoid dimer natural product); mutations in PfPARE confer >250-fold resistance to chlorajaponilide C, but resistance to some structurally related dimers is not mediated by PfPARE, revealing substrate specificity of the esterase.","method":"In vitro resistance selection, whole-genome sequencing, structure-resistance relationship analysis","journal":"ACS infectious diseases","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic resistance selection with sequencing confirms PfPARE involvement; no direct in vitro enzymatic assay of PfPARE with chlorajaponilide C reported in abstract","pmids":["32970404"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2019,"finding":"PfPARE (PF3D7_1252600) was detected as an active serine hydrolase in the asexual erythrocytic stage of P. falciparum using fluorophosphonate-based affinity capture, demonstrating it is catalytically active in live parasites.","method":"Fluorophosphonate-based activity-based protein profiling (affinity capture) coupled to mass spectrometry","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — activity-based probe confirmed active-site reactivity in situ, single lab, single method","pmids":["31772212"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"PfPARE (PF3D7_1252600) locus is expressed throughout the intraerythrocytic cycle, is not essential for asexual parasite growth, and is highly conserved across P. falciparum strains; disruption of the locus (replacement with mNeonGreen reporter) results in negligible fitness defect.","method":"CRISPR-based gene disruption/reporter insertion, competitive growth assay (fluorescence-based), flow cytometry","journal":"Frontiers in cellular and infection microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean CRISPR disruption with quantitative fitness assay; two orthogonal measurements (fluorescence growth assay + fitness quantification)","pmids":["36189342"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":"Dd2"}]},{"year":2025,"finding":"PfPARE (PF3D7_1252600) is a membrane-associated enzyme with substantial presence at the parasite periphery; it mediates low-level hydrolysis of lysophosphatidylcholine (LPC); loss of PARE alone has no effect on LPC-derived fatty acid scavenging, but combined knockdown of PARE with XL2 and XLH4 impairs both choline and fatty acid scavenging from LPC, and triple-deficient parasites cannot complete a replication cycle when LPC is the sole exogenous fatty acid source.","method":"Gene knockdown/knockout, fluorescence microscopy (subcellular localization), lipid scavenging assays in defined media, competitive growth assay","journal":"International journal for parasitology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic disruption combined with functional lipid assays and subcellular localization imaging; single lab but multiple orthogonal methods","pmids":["41043577"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"finding":"PfPARE (PF3D7_1252600) esterase substrate specificity was characterized using a fluorogenic ester library and compared to that of the imported erythrocyte enzyme APEH; PfPARE showed distinct substrate preferences relative to APEH, particularly differing in activity toward substrates with branching at the alpha carbon.","method":"Fluorogenic ester library structure-activity relationship profiling, comparative enzymatic assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro enzymatic characterization with substrate library; single study, results presented comparatively with APEH","pmids":["40035755"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2023,"finding":"PfPARE (PF3D7_1252600, annotated as PF3D7_0709700 in that study — the prodrug activation and resistance esterase) localizes to the parasite plasma membrane in P. falciparum gametocytes; disruption of the pfpare gene did not affect gametocyte development or egress.","method":"Fluorescence microscopy (subcellular localization), gene disruption, gametocyte development and egress assays","journal":"Molecular microbiology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — localization and negative phenotypic result in gametocytes; single lab, single method for localization; note PF3D7_0709700 is cited as PfPARE in this abstract, which may refer to a different locus — confidence lowered due to possible locus ambiguity","pmids":["38131156"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"PfPARE (PF3D7_1252600) is a catalytically active serine esterase expressed throughout the intraerythrocytic cycle, localized at the parasite periphery/plasma membrane, that activates multiple esterified prodrugs (pepstatin esters, MMV011438, AN13762, chlorajaponilide C) by hydrolysis; it also contributes redundantly to lysophosphatidylcholine catabolism alongside two exported lipases; it is non-essential for asexual growth under standard conditions, but loss-of-function mutations in PfPARE are a primary mechanism of resistance to prodrug antimalarials that require esterase-mediated activation."},"narrative":{"mechanistic_narrative":"PfPARE (PF3D7_1252600) is a catalytically active serine esterase of P. falciparum that functions in both xenobiotic prodrug activation and host-lipid catabolism during the intraerythrocytic cycle [PMID:28106035, PMID:31772212]. It is a membrane-associated enzyme with substantial presence at the parasite periphery/plasma membrane [PMID:41043577]. Its best-defined activity is the hydrolytic de-esterification of chemically diverse esterified compounds: recombinant PfPARE hydrolyzes pepstatin esters and activates the prodrug MMV011438 [PMID:28106035], processes the benzoxaborole AN13762 to its active form AN10248 [PMID:31992618], and mediates the potency of the natural product chlorajaponilide C [PMID:32970404], with loss-of-function mutations in each case conferring resistance—establishing esterase-dependent prodrug activation as a resistance mechanism. Substrate profiling with a fluorogenic ester library shows PfPARE has distinct preferences relative to the imported erythrocyte enzyme APEH, notably differing toward substrates with alpha-carbon branching [PMID:40035755]. Beyond prodrug activation, PfPARE contributes redundantly to catabolism of host lysophosphatidylcholine: PfPARE alone is dispensable for LPC-derived scavenging, but its combined knockdown with the lipases XL2 and XLH4 impairs both choline and fatty-acid scavenging and abolishes replication when LPC is the sole fatty-acid source [PMID:41043577]. The gene is expressed throughout the asexual cycle, is highly conserved across strains, and is non-essential for asexual growth under standard conditions [PMID:36189342].","teleology":[{"year":2017,"claim":"Established that PF3D7_1252600 is a bona fide esterase whose catalytic activity is required to convert esterified prodrugs into their active forms, answering how certain antimalarial esters become active in parasites.","evidence":"Resistant mutant selection with whole-genome sequencing plus recombinant protein in vitro hydrolysis assays on pepstatin esters and MMV011438","pmids":["28106035"],"confidence":"High","gaps":["No crystal structure or defined catalytic-residue geometry reported","Endogenous physiological substrate not identified in this study"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2019,"claim":"Confirmed that PfPARE is catalytically active in live asexual-stage parasites rather than only as a recombinant protein, validating in situ relevance of its serine hydrolase activity.","evidence":"Fluorophosphonate-based activity-based protein profiling coupled to mass spectrometry in erythrocytic-stage P. falciparum","pmids":["31772212"],"confidence":"Medium","gaps":["Single method and single lab","Does not link in situ activity to a specific endogenous substrate"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"claim":"Generalized the prodrug-activation role beyond the initial compounds by showing PfPARE activates the benzoxaborole AN13762 and that its mutation confers resistance, reinforcing esterase-dependent activation as a resistance liability.","evidence":"In vitro resistance selection, engineered introduction of PfPARE mutations, and recombinant PfPARE enzymatic assay","pmids":["31992618"],"confidence":"High","gaps":["Resistance was only low-level, leaving other activation routes possible","Kinetics of AN13762 hydrolysis not quantified"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"claim":"Extended the substrate range to a natural-product dimer (chlorajaponilide C) while showing structurally related dimers are not PfPARE-dependent, revealing that the enzyme has defined substrate specificity.","evidence":"In vitro resistance selection with whole-genome sequencing and structure-resistance relationship analysis","pmids":["32970404"],"confidence":"Medium","gaps":["No direct in vitro enzymatic assay of PfPARE with chlorajaponilide C","Structural basis of the specificity difference among dimers unresolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"claim":"Determined that PfPARE is expressed throughout the intraerythrocytic cycle and dispensable for asexual growth, framing it as a conditionally important enzyme whose loss is tolerated except under prodrug pressure.","evidence":"CRISPR disruption with mNeonGreen reporter insertion and fluorescence-based competitive growth assay in P. falciparum Dd2","pmids":["36189342"],"confidence":"Medium","gaps":["Fitness assessed only under standard culture conditions","Endogenous function not addressed by disruption phenotype"],"attribution":[{"species":"Plasmodium falciparum","strain":"Dd2"}]},{"year":2023,"claim":"Localized PfPARE to the plasma membrane in gametocytes and showed disruption does not impair gametocyte development or egress, extending its non-essentiality across stages.","evidence":"Fluorescence microscopy localization plus gene disruption with gametocyte development and egress assays","pmids":["38131156"],"confidence":"Low","gaps":["Study cites the locus as PF3D7_0709700, introducing possible locus ambiguity","Single-method localization in a single lab","No functional gametocyte-stage substrate identified"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"claim":"Defined PfPARE's substrate preference relative to the imported host enzyme APEH, distinguishing the two esterases functionally and clarifying which ester chemistries PfPARE favors.","evidence":"Fluorogenic ester library structure-activity profiling and comparative enzymatic assay","pmids":["40035755"],"confidence":"Medium","gaps":["Preferences defined with synthetic reporters, not endogenous substrates","Single study"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"claim":"Assigned PfPARE an endogenous physiological role in lysophosphatidylcholine catabolism, showing it acts redundantly with the lipases XL2 and XLH4 to scavenge choline and fatty acids from LPC.","evidence":"Gene knockdown/knockout, subcellular localization microscopy, LPC scavenging assays in defined media, and competitive growth assays","pmids":["41043577"],"confidence":"Medium","gaps":["PfPARE contribution alone is minor and only revealed by combined knockdown","Direct enzymatic hydrolysis of LPC by PfPARE not kinetically characterized","Molecular basis of functional redundancy with XL2/XLH4 unresolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"The native structural and mechanistic determinants of PfPARE (catalytic-residue geometry, structure) and the full physiological substrate spectrum linking its prodrug and lipid-catabolic activities remain to be resolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model or defined active-site architecture in the corpus","Whether the same active site handles both xenobiotic esters and LPC is untested","Physiological trigger and regulation of PfPARE activity unknown"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["XL2 (FUNCTIONAL REDUNDANCY IN LPC CATABOLISM) [#5]","XLH4 (FUNCTIONAL REDUNDANCY IN LPC CATABOLISM) [#5]"],"other_free_text":["Activates esterified prodrugs pepstatin esters, MMV011438, benzoxaborole AN13762 (to AN10248), and chlorajaponilide C by hydrolysis [#0, #1, #2]","Loss-of-function mutations confer resistance to these esterase-activated antimalarials [#0, #1, #2]","Substrate specificity distinct from the imported erythrocyte enzyme APEH, differing toward alpha-carbon-branched substrates [#6]","Expressed throughout the intraerythrocytic cycle, highly conserved across strains, non-essential for asexual growth under standard conditions [#4]","Disruption does not affect gametocyte development or egress [#7]"]}},"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":"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":"31772212","id":"PMC_31772212","title":"Functional annotation of serine hydrolases in the asexual erythrocytic stage of Plasmodium falciparum.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31772212","citation_count":16,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["curated_ref"],"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":"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":9459,"output_tokens":2284,"usd":0.031318,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":7559,"output_tokens":3577,"usd":0.06361,"stage2_stop_reason":"end_turn"},"total_usd":0.094928,"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_1252600) is a functional esterase required for activation of esterified pepstatin prodrugs and MMV011438; recombinant PfPARE hydrolyses pepstatin esters and de-esterifies MMV011438 in vitro, and mutations in PfPARE confer resistance to these compounds.\",\n      \"method\": \"Resistant mutant selection, whole-genome sequencing, recombinant protein enzymatic assay (in vitro hydrolysis), synthesis of derivatives\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — recombinant protein in vitro enzymatic assay combined with resistance selection and mutagenesis, establishing catalytic mechanism and prodrug activation role\",\n      \"pmids\": [\"28106035\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PfPARE (PF3D7_1252600) activates the benzoxaborole AN13762 by hydrolyzing it to AN10248; mutations in PfPARE prevent this processing and confer low-level resistance to AN13762, establishing PfPARE-mediated prodrug activation as a resistance mechanism.\",\n      \"method\": \"In vitro resistance selection, whole-genome sequencing, introduction of PfPARE mutations by genetic engineering, recombinant PfPARE enzymatic assay\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — recombinant enzyme assay plus introduction of specific mutations confirmed loss of activation, replicated the mechanism from PMID:28106035\",\n      \"pmids\": [\"31992618\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PfPARE (PF3D7_1252600) mediates the in vitro potency of chlorajaponilide C (a lindenane sesquiterpenoid dimer natural product); mutations in PfPARE confer >250-fold resistance to chlorajaponilide C, but resistance to some structurally related dimers is not mediated by PfPARE, revealing substrate specificity of the esterase.\",\n      \"method\": \"In vitro resistance selection, whole-genome sequencing, structure-resistance relationship analysis\",\n      \"journal\": \"ACS infectious diseases\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic resistance selection with sequencing confirms PfPARE involvement; no direct in vitro enzymatic assay of PfPARE with chlorajaponilide C reported in abstract\",\n      \"pmids\": [\"32970404\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PfPARE (PF3D7_1252600) was detected as an active serine hydrolase in the asexual erythrocytic stage of P. falciparum using fluorophosphonate-based affinity capture, demonstrating it is catalytically active in live parasites.\",\n      \"method\": \"Fluorophosphonate-based activity-based protein profiling (affinity capture) coupled to mass spectrometry\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — activity-based probe confirmed active-site reactivity in situ, single lab, single method\",\n      \"pmids\": [\"31772212\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PfPARE (PF3D7_1252600) locus is expressed throughout the intraerythrocytic cycle, is not essential for asexual parasite growth, and is highly conserved across P. falciparum strains; disruption of the locus (replacement with mNeonGreen reporter) results in negligible fitness defect.\",\n      \"method\": \"CRISPR-based gene disruption/reporter insertion, competitive growth assay (fluorescence-based), flow cytometry\",\n      \"journal\": \"Frontiers in cellular and infection microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean CRISPR disruption with quantitative fitness assay; two orthogonal measurements (fluorescence growth assay + fitness quantification)\",\n      \"pmids\": [\"36189342\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"Dd2\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PfPARE (PF3D7_1252600) is a membrane-associated enzyme with substantial presence at the parasite periphery; it mediates low-level hydrolysis of lysophosphatidylcholine (LPC); loss of PARE alone has no effect on LPC-derived fatty acid scavenging, but combined knockdown of PARE with XL2 and XLH4 impairs both choline and fatty acid scavenging from LPC, and triple-deficient parasites cannot complete a replication cycle when LPC is the sole exogenous fatty acid source.\",\n      \"method\": \"Gene knockdown/knockout, fluorescence microscopy (subcellular localization), lipid scavenging assays in defined media, competitive growth assay\",\n      \"journal\": \"International journal for parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic disruption combined with functional lipid assays and subcellular localization imaging; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"41043577\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PfPARE (PF3D7_1252600) esterase substrate specificity was characterized using a fluorogenic ester library and compared to that of the imported erythrocyte enzyme APEH; PfPARE showed distinct substrate preferences relative to APEH, particularly differing in activity toward substrates with branching at the alpha carbon.\",\n      \"method\": \"Fluorogenic ester library structure-activity relationship profiling, comparative enzymatic assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro enzymatic characterization with substrate library; single study, results presented comparatively with APEH\",\n      \"pmids\": [\"40035755\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"PfPARE (PF3D7_1252600, annotated as PF3D7_0709700 in that study — the prodrug activation and resistance esterase) localizes to the parasite plasma membrane in P. falciparum gametocytes; disruption of the pfpare gene did not affect gametocyte development or egress.\",\n      \"method\": \"Fluorescence microscopy (subcellular localization), gene disruption, gametocyte development and egress assays\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — localization and negative phenotypic result in gametocytes; single lab, single method for localization; note PF3D7_0709700 is cited as PfPARE in this abstract, which may refer to a different locus — confidence lowered due to possible locus ambiguity\",\n      \"pmids\": [\"38131156\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"PfPARE (PF3D7_1252600) is a catalytically active serine esterase expressed throughout the intraerythrocytic cycle, localized at the parasite periphery/plasma membrane, that activates multiple esterified prodrugs (pepstatin esters, MMV011438, AN13762, chlorajaponilide C) by hydrolysis; it also contributes redundantly to lysophosphatidylcholine catabolism alongside two exported lipases; it is non-essential for asexual growth under standard conditions, but loss-of-function mutations in PfPARE are a primary mechanism of resistance to prodrug antimalarials that require esterase-mediated activation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PfPARE (PF3D7_1252600) is a catalytically active serine esterase of P. falciparum that functions in both xenobiotic prodrug activation and host-lipid catabolism during the intraerythrocytic cycle [#0, #3]. It is a membrane-associated enzyme with substantial presence at the parasite periphery/plasma membrane [#5]. Its best-defined activity is the hydrolytic de-esterification of chemically diverse esterified compounds: recombinant PfPARE hydrolyzes pepstatin esters and activates the prodrug MMV011438 [#0], processes the benzoxaborole AN13762 to its active form AN10248 [#1], and mediates the potency of the natural product chlorajaponilide C [#2], with loss-of-function mutations in each case conferring resistance—establishing esterase-dependent prodrug activation as a resistance mechanism. Substrate profiling with a fluorogenic ester library shows PfPARE has distinct preferences relative to the imported erythrocyte enzyme APEH, notably differing toward substrates with alpha-carbon branching [#6]. Beyond prodrug activation, PfPARE contributes redundantly to catabolism of host lysophosphatidylcholine: PfPARE alone is dispensable for LPC-derived scavenging, but its combined knockdown with the lipases XL2 and XLH4 impairs both choline and fatty-acid scavenging and abolishes replication when LPC is the sole fatty-acid source [#5]. The gene is expressed throughout the asexual cycle, is highly conserved across strains, and is non-essential for asexual growth under standard conditions [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Established that PF3D7_1252600 is a bona fide esterase whose catalytic activity is required to convert esterified prodrugs into their active forms, answering how certain antimalarial esters become active in parasites.\",\n      \"evidence\": \"Resistant mutant selection with whole-genome sequencing plus recombinant protein in vitro hydrolysis assays on pepstatin esters and MMV011438\",\n      \"pmids\": [\"28106035\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No crystal structure or defined catalytic-residue geometry reported\",\n        \"Endogenous physiological substrate not identified in this study\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Confirmed that PfPARE is catalytically active in live asexual-stage parasites rather than only as a recombinant protein, validating in situ relevance of its serine hydrolase activity.\",\n      \"evidence\": \"Fluorophosphonate-based activity-based protein profiling coupled to mass spectrometry in erythrocytic-stage P. falciparum\",\n      \"pmids\": [\"31772212\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single method and single lab\",\n        \"Does not link in situ activity to a specific endogenous substrate\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Generalized the prodrug-activation role beyond the initial compounds by showing PfPARE activates the benzoxaborole AN13762 and that its mutation confers resistance, reinforcing esterase-dependent activation as a resistance liability.\",\n      \"evidence\": \"In vitro resistance selection, engineered introduction of PfPARE mutations, and recombinant PfPARE enzymatic assay\",\n      \"pmids\": [\"31992618\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Resistance was only low-level, leaving other activation routes possible\",\n        \"Kinetics of AN13762 hydrolysis not quantified\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Extended the substrate range to a natural-product dimer (chlorajaponilide C) while showing structurally related dimers are not PfPARE-dependent, revealing that the enzyme has defined substrate specificity.\",\n      \"evidence\": \"In vitro resistance selection with whole-genome sequencing and structure-resistance relationship analysis\",\n      \"pmids\": [\"32970404\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct in vitro enzymatic assay of PfPARE with chlorajaponilide C\",\n        \"Structural basis of the specificity difference among dimers unresolved\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Determined that PfPARE is expressed throughout the intraerythrocytic cycle and dispensable for asexual growth, framing it as a conditionally important enzyme whose loss is tolerated except under prodrug pressure.\",\n      \"evidence\": \"CRISPR disruption with mNeonGreen reporter insertion and fluorescence-based competitive growth assay in P. falciparum Dd2\",\n      \"pmids\": [\"36189342\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Fitness assessed only under standard culture conditions\",\n        \"Endogenous function not addressed by disruption phenotype\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"Dd2\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Localized PfPARE to the plasma membrane in gametocytes and showed disruption does not impair gametocyte development or egress, extending its non-essentiality across stages.\",\n      \"evidence\": \"Fluorescence microscopy localization plus gene disruption with gametocyte development and egress assays\",\n      \"pmids\": [\"38131156\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Study cites the locus as PF3D7_0709700, introducing possible locus ambiguity\",\n        \"Single-method localization in a single lab\",\n        \"No functional gametocyte-stage substrate identified\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Defined PfPARE's substrate preference relative to the imported host enzyme APEH, distinguishing the two esterases functionally and clarifying which ester chemistries PfPARE favors.\",\n      \"evidence\": \"Fluorogenic ester library structure-activity profiling and comparative enzymatic assay\",\n      \"pmids\": [\"40035755\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Preferences defined with synthetic reporters, not endogenous substrates\",\n        \"Single study\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Assigned PfPARE an endogenous physiological role in lysophosphatidylcholine catabolism, showing it acts redundantly with the lipases XL2 and XLH4 to scavenge choline and fatty acids from LPC.\",\n      \"evidence\": \"Gene knockdown/knockout, subcellular localization microscopy, LPC scavenging assays in defined media, and competitive growth assays\",\n      \"pmids\": [\"41043577\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"PfPARE contribution alone is minor and only revealed by combined knockdown\",\n        \"Direct enzymatic hydrolysis of LPC by PfPARE not kinetically characterized\",\n        \"Molecular basis of functional redundancy with XL2/XLH4 unresolved\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The native structural and mechanistic determinants of PfPARE (catalytic-residue geometry, structure) and the full physiological substrate spectrum linking its prodrug and lipid-catabolic activities remain to be resolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No structural model or defined active-site architecture in the corpus\",\n        \"Whether the same active site handles both xenobiotic esters and LPC is untested\",\n        \"Physiological trigger and regulation of PfPARE activity unknown\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0052689\", \"supporting_discovery_ids\": [0, 1, 6]},\n      {\"term_id\": \"GO:0008236\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0016298\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [5, 7]},\n      {\"term_id\": \"GO:0016020\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0046471\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"GO:0006629\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"XL2 (functional redundancy in LPC catabolism) [#5]\",\n      \"XLH4 (functional redundancy in LPC catabolism) [#5]\"\n    ],\n    \"other_free_text\": [\n      \"Activates esterified prodrugs pepstatin esters, MMV011438, benzoxaborole AN13762 (to AN10248), and chlorajaponilide C by hydrolysis [#0, #1, #2]\",\n      \"Loss-of-function mutations confer resistance to these esterase-activated antimalarials [#0, #1, #2]\",\n      \"Substrate specificity distinct from the imported erythrocyte enzyme APEH, differing toward alpha-carbon-branched substrates [#6]\",\n      \"Expressed throughout the intraerythrocytic cycle, highly conserved across strains, non-essential for asexual growth under standard conditions [#4]\",\n      \"Disruption does not affect gametocyte development or egress [#7]\"\n    ]\n  }\n}","audit_flag":{"gene":"PF3D7_1252600","tier":"IDENTITY_CHECK","verdict":"identity unverified","subtype":"names_other_cards","uniprot_band":"","rules_fired":"R12","issue":"No cited paper names this card; 5 of 8 cited papers name other catalogue genes (PF3D7_0709700, PF3D7_1438500, PF3D7_0924000). The summary may describe one of those genes."},"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_1252600","name":null,"product":"esterase, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"","evaluation":null}