{"gene":"PF3D7_1211400","run_date":"2026-09-08T14:19:06","timeline":{"discoveries":[{"year":2008,"finding":"PfJ4 (PF3D7_1211400) expression increases upon heat shock in P. falciparum-infected erythrocytes, and immunofluorescence and immuno-electron microscopy localized PfJ4 to the parasite nucleus and cytoplasm, with some detection in the erythrocyte cytoplasm of infected erythrocytes. Immunoprecipitation and size exclusion chromatography indicated that PfJ4 and PfHsp70-1 may directly or indirectly interact, suggesting involvement in cytoprotection.","method":"Western blot on cellular fractions, immunofluorescence microscopy, immuno-electron microscopy, immunoprecipitation, size exclusion chromatography, functional complementation in E. coli dnaJ cbpA mutant strain","journal":"The international journal of biochemistry & cell biology","confidence":"Medium","confidence_rationale":"Tier 2/3 / Moderate — multiple orthogonal methods (IEM, immunoprecipitation, size exclusion chromatography, functional complementation) from a single lab; interaction described as direct or indirect without reconstitution","pmids":["18674634"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2008,"finding":"PfJ4 (PF3D7_1211400) is a type II Hsp40 protein that can functionally replace E. coli Hsp40 proteins (DnaJ/CbpA) in a dnaJ cbpA double mutant strain, establishing it has DnaJ-like cochaperone activity.","method":"Functional complementation assay in E. coli dnaJ cbpA mutant strain","journal":"The international journal of biochemistry & cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — single lab, single complementation assay demonstrating functional activity","pmids":["18674634"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"PfJ4 (PF3D7_1211400) is a type II Hsp40 cochaperone that localizes to the P. falciparum parasite nucleus and cytoplasm (and occasionally the infected erythrocyte cytoplasm), is upregulated upon heat shock, can functionally substitute for E. coli DnaJ/CbpA, and associates (directly or indirectly) with the cytosolic chaperone PfHsp70-1, suggesting a role in cytoprotection and parasite survival within the erythrocyte."},"narrative":{"mechanistic_narrative":"PfJ4 (PF3D7_1211400) is a type II Hsp40 cochaperone of Plasmodium falciparum implicated in cytoprotection during the parasite's intraerythrocytic stage [PMID:18674634]. Its expression rises upon heat shock, and it localizes to the parasite nucleus and cytoplasm, with some detection in the cytoplasm of the infected erythrocyte [PMID:18674634]. PfJ4 possesses functional DnaJ-like cochaperone activity, as it substitutes for the E. coli Hsp40 proteins DnaJ and CbpA in a dnaJ cbpA double-mutant strain [PMID:18674634]. Consistent with a cochaperone role, immunoprecipitation and size exclusion chromatography indicate that PfJ4 associates, directly or indirectly, with the cytosolic chaperone PfHsp70-1 [PMID:18674634]. Beyond these findings, no further mechanistic detail — including client substrates, the structural basis of the PfHsp70-1 interaction, or its role in parasite survival — has been characterized in the available corpus.","teleology":[{"year":2008,"claim":"To establish whether PfJ4 acts as a functional Hsp40 cochaperone, its ability to substitute for bacterial Hsp40 proteins was tested, confirming genuine DnaJ-like activity rather than mere sequence homology.","evidence":"Functional complementation of an E. coli dnaJ cbpA double-mutant strain","pmids":["18674634"],"confidence":"Medium","gaps":["Does not identify native P. falciparum client proteins","Complementation shows generic DnaJ activity but not the parasite-specific partner or substrate specificity"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2008,"claim":"To place PfJ4 in a cellular pathway, its heat-shock regulation, subcellular distribution, and partner chaperone were mapped, linking it to PfHsp70-1 and implicating it in cytoprotection.","evidence":"Western blot on cellular fractions, immunofluorescence and immuno-electron microscopy, immunoprecipitation, and size exclusion chromatography in P. falciparum-infected erythrocytes","pmids":["18674634"],"confidence":"Medium","gaps":["PfJ4–PfHsp70-1 interaction described as direct or indirect without reconstitution","No reciprocal validation or in vitro reconstitution of the chaperone pair","Functional consequence for parasite survival not tested by genetic knockdown or knockout"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"Whether PfJ4 is essential for parasite viability, what client proteins it delivers to PfHsp70-1, and the structural/biochemical basis of that interaction remain unestablished in the available corpus.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No genetic essentiality data (knockdown/knockout)","No identified client substrates","No reconstituted or structural characterization of the PfJ4–PfHsp70-1 interaction"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["PFHSP70-1"],"other_free_text":["Type II Hsp40 cochaperone [#1]","Expression upregulated upon heat shock [#0]","Functionally complements E. coli dnaJ cbpA double mutant [#1]","Association with PfHsp70-1 reported as direct or indirect, without reconstitution [#0]"]}},"prefetch_data":{},"corpus_meta":[{"pmid":"1585456","id":"PMC_1585456","title":"A module of the DnaJ heat shock proteins found in malaria parasites.","date":"1992","source":"Trends in biochemical sciences","url":"https://pubmed.ncbi.nlm.nih.gov/1585456","citation_count":84,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"25849211","id":"PMC_25849211","title":"Submicroscopic and asymptomatic Plasmodium falciparum and Plasmodium vivax infections are common in western Thailand - molecular and serological evidence.","date":"2015","source":"Malaria journal","url":"https://pubmed.ncbi.nlm.nih.gov/25849211","citation_count":76,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"18674634","id":"PMC_18674634","title":"The Plasmodium falciparum heat shock protein 40, Pfj4, associates with heat shock protein 70 and shows similar heat induction and localisation patterns.","date":"2008","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/18674634","citation_count":43,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfJ4","DNAJ","Pfj4"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"19339102","id":"PMC_19339102","title":"Hsp70-1 from Plasmodium falciparum: protein stability, domain analysis and chaperone activity.","date":"2009","source":"Biophysical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19339102","citation_count":33,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"22920898","id":"PMC_22920898","title":"Hsp70s and J proteins of Plasmodium parasites infecting rodents and primates: structure, function, clinical relevance, and drug targets.","date":"2013","source":"Current pharmaceutical design","url":"https://pubmed.ncbi.nlm.nih.gov/22920898","citation_count":32,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"9274886","id":"PMC_9274886","title":"Cloning and characterization of heat shock protein DnaJ homologues from Plasmodium falciparum and comparison with ring infected erythrocyte surface antigen.","date":"1997","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/9274886","citation_count":28,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"34569020","id":"PMC_34569020","title":"General Structural and Functional Features of Molecular Chaperones.","date":"2021","source":"Advances in experimental medicine and biology","url":"https://pubmed.ncbi.nlm.nih.gov/34569020","citation_count":27,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"28322872","id":"PMC_28322872","title":"Plasmodium Hsp40 and human Hsp70: A potential cochaperone-chaperone complex.","date":"2017","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/28322872","citation_count":23,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfDNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"20487289","id":"PMC_20487289","title":"Nuclear-encoded DnaJ homologue of Plasmodium falciparum interacts with replication ori of the apicoplast genome.","date":"2010","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/20487289","citation_count":19,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ","PfDNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"25701168","id":"PMC_25701168","title":"PFB0595w is a Plasmodium falciparum J protein that co-localizes with PfHsp70-1 and can stimulate its in vitro ATP hydrolysis activity.","date":"2015","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/25701168","citation_count":18,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"26348884","id":"PMC_26348884","title":"In silico identification of genetically attenuated vaccine candidate genes for Plasmodium liver stage.","date":"2015","source":"Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/26348884","citation_count":16,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"7969262","id":"PMC_7969262","title":"Establishing a physical map of chromosome No. 4 of Plasmodium falciparum.","date":"1994","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/7969262","citation_count":16,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["DNAJ"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7760,"output_tokens":733,"usd":0.017137,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5379,"output_tokens":1669,"usd":0.03431,"stage2_stop_reason":"end_turn"},"total_usd":0.051447,"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\": 2008,\n      \"finding\": \"PfJ4 (PF3D7_1211400) expression increases upon heat shock in P. falciparum-infected erythrocytes, and immunofluorescence and immuno-electron microscopy localized PfJ4 to the parasite nucleus and cytoplasm, with some detection in the erythrocyte cytoplasm of infected erythrocytes. Immunoprecipitation and size exclusion chromatography indicated that PfJ4 and PfHsp70-1 may directly or indirectly interact, suggesting involvement in cytoprotection.\",\n      \"method\": \"Western blot on cellular fractions, immunofluorescence microscopy, immuno-electron microscopy, immunoprecipitation, size exclusion chromatography, functional complementation in E. coli dnaJ cbpA mutant strain\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2/3 / Moderate — multiple orthogonal methods (IEM, immunoprecipitation, size exclusion chromatography, functional complementation) from a single lab; interaction described as direct or indirect without reconstitution\",\n      \"pmids\": [\"18674634\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"PfJ4 (PF3D7_1211400) is a type II Hsp40 protein that can functionally replace E. coli Hsp40 proteins (DnaJ/CbpA) in a dnaJ cbpA double mutant strain, establishing it has DnaJ-like cochaperone activity.\",\n      \"method\": \"Functional complementation assay in E. coli dnaJ cbpA mutant strain\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — single lab, single complementation assay demonstrating functional activity\",\n      \"pmids\": [\"18674634\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"PfJ4 (PF3D7_1211400) is a type II Hsp40 cochaperone that localizes to the P. falciparum parasite nucleus and cytoplasm (and occasionally the infected erythrocyte cytoplasm), is upregulated upon heat shock, can functionally substitute for E. coli DnaJ/CbpA, and associates (directly or indirectly) with the cytosolic chaperone PfHsp70-1, suggesting a role in cytoprotection and parasite survival within the erythrocyte.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PfJ4 (PF3D7_1211400) is a type II Hsp40 cochaperone of Plasmodium falciparum implicated in cytoprotection during the parasite's intraerythrocytic stage [#0]. Its expression rises upon heat shock, and it localizes to the parasite nucleus and cytoplasm, with some detection in the cytoplasm of the infected erythrocyte [#0]. PfJ4 possesses functional DnaJ-like cochaperone activity, as it substitutes for the E. coli Hsp40 proteins DnaJ and CbpA in a dnaJ cbpA double-mutant strain [#1]. Consistent with a cochaperone role, immunoprecipitation and size exclusion chromatography indicate that PfJ4 associates, directly or indirectly, with the cytosolic chaperone PfHsp70-1 [#0]. Beyond these findings, no further mechanistic detail — including client substrates, the structural basis of the PfHsp70-1 interaction, or its role in parasite survival — has been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"To establish whether PfJ4 acts as a functional Hsp40 cochaperone, its ability to substitute for bacterial Hsp40 proteins was tested, confirming genuine DnaJ-like activity rather than mere sequence homology.\",\n      \"evidence\": \"Functional complementation of an E. coli dnaJ cbpA double-mutant strain\",\n      \"pmids\": [\"18674634\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not identify native P. falciparum client proteins\", \"Complementation shows generic DnaJ activity but not the parasite-specific partner or substrate specificity\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"To place PfJ4 in a cellular pathway, its heat-shock regulation, subcellular distribution, and partner chaperone were mapped, linking it to PfHsp70-1 and implicating it in cytoprotection.\",\n      \"evidence\": \"Western blot on cellular fractions, immunofluorescence and immuno-electron microscopy, immunoprecipitation, and size exclusion chromatography in P. falciparum-infected erythrocytes\",\n      \"pmids\": [\"18674634\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"PfJ4–PfHsp70-1 interaction described as direct or indirect without reconstitution\", \"No reciprocal validation or in vitro reconstitution of the chaperone pair\", \"Functional consequence for parasite survival not tested by genetic knockdown or knockout\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Whether PfJ4 is essential for parasite viability, what client proteins it delivers to PfHsp70-1, and the structural/biochemical basis of that interaction remain unestablished in the available corpus.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No genetic essentiality data (knockdown/knockout)\", \"No identified client substrates\", \"No reconstituted or structural characterization of the PfJ4–PfHsp70-1 interaction\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0001671\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0051087\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0031072\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005737\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0020036\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0009408\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0006457\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"PfHsp70-1\"],\n    \"other_free_text\": [\n      \"Type II Hsp40 cochaperone [#1]\",\n      \"Expression upregulated upon heat shock [#0]\",\n      \"Functionally complements E. coli dnaJ cbpA double mutant [#1]\",\n      \"Association with PfHsp70-1 reported as direct or indirect, without reconstitution [#0]\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_1211400","name":null,"product":"heat shock protein DNAJ homologue Pfj4","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_0609900","name":null,"product":"heat shock protein DNAJ homologue Pfj4, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_1311500","name":null,"product":"Heat shock protein DnaJ, Pfj4  homologue, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"PfJ4","evaluation":null}