{"gene":"PF3D7_0515500","run_date":"2026-09-07T10:55:52","timeline":{"discoveries":[{"year":2020,"finding":"GEP1 is required for xanthurenic acid (XA)-stimulated cGMP synthesis and the subsequent cGMP/PKG-dependent signaling events in gametocytes, including Ca2+ mobilization, gamete formation, and gamete egress from erythrocytes; disruption of GEP1 abolishes all these downstream events.","method":"CRISPR/Cas9-based functional screening and gene disruption in Plasmodium yoelii gametocytes, with phenotypic readouts of cGMP levels, Ca2+ mobilization, gamete formation, and egress","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean loss-of-function with multiple orthogonal cellular phenotype readouts (cGMP, Ca2+, gamete formation, egress) in a rigorous CRISPR screen","pmids":["32273496"],"is_preprint":false,"attribution":[{"species":"Plasmodium yoelii","strain":""}]},{"year":2020,"finding":"GEP1 physically interacts with GCα (a cGMP-synthesizing guanylyl cyclase) in gametocytes, and both proteins co-localize in cytoplasmic puncta of male and female gametocytes; depletion of GCα mimics the GEP1 disruption phenotype, placing GEP1 upstream of or in complex with GCα in the XA-sensing/transduction pathway.","method":"Co-immunoprecipitation (GEP1–GCα interaction), immunofluorescence/live imaging (cytoplasmic puncta localization), and GCα depletion epistasis in Plasmodium yoelii","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal interaction (Co-IP), direct localization experiment, and genetic epistasis in a single rigorous study with multiple orthogonal methods","pmids":["32273496"],"is_preprint":false,"attribution":[{"species":"Plasmodium yoelii","strain":""}]},{"year":2025,"finding":"GEP1 is essential for both male and female gametogenesis in Plasmodium falciparum; CRISPR-Cas9-generated PfGEP1 loss-of-function lines completely fail to undergo gametogenesis even upon XA stimulation, temperature drop, or treatment with the phosphodiesterase inhibitor Zaprinast, indicating GEP1 acts at a step that cannot be bypassed by pharmacological elevation of cGMP.","method":"CRISPR-Cas9 gene deletion in Plasmodium falciparum with gametogenesis assays under XA stimulation, temperature drop, and Zaprinast treatment","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean KO with multiple stimulation conditions tested, defining an XA-independent essential function in the human malaria parasite","pmids":["41084330"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"GEP1 (PF3D7_0515500) is an intracellular membrane protein expressed in cytoplasmic puncta of both male and female gametocytes that physically interacts with the cGMP-synthesizing enzyme GCα and is required upstream of cGMP production for xanthurenic acid-triggered gametogenesis in Plasmodium yoelii; in Plasmodium falciparum, GEP1 is absolutely essential for gametogenesis through both XA-dependent and XA-independent mechanisms, as its deletion blocks all gamete activation even when cGMP is pharmacologically elevated by Zaprinast."},"narrative":{"mechanistic_narrative":"GEP1 (PF3D7_0515500) is an intracellular membrane protein required for gametogenesis in malaria parasites, acting at the earliest steps of the signaling cascade that converts an environmental activation cue into gamete formation [PMID:32273496]. In Plasmodium yoelii, GEP1 is essential for xanthurenic acid (XA)-stimulated cGMP synthesis and the downstream cGMP/PKG-dependent events, including Ca2+ mobilization, gamete formation, and gamete egress; its disruption abolishes all of these responses [PMID:32273496]. Mechanistically, GEP1 physically interacts with the cGMP-synthesizing guanylyl cyclase GCα and co-localizes with it in cytoplasmic puncta of both male and female gametocytes, and GCα depletion phenocopies GEP1 loss, placing GEP1 upstream of or in complex with GCα in the XA-sensing/transduction pathway [PMID:32273496]. In Plasmodium falciparum, GEP1 is absolutely essential for both male and female gametogenesis: loss-of-function parasites fail to activate under XA, temperature drop, or the phosphodiesterase inhibitor Zaprinast, indicating GEP1 acts at a step that cannot be bypassed by pharmacological elevation of cGMP and defines an XA-independent essential function [PMID:41084330]. Beyond its requirement for GCα-dependent signaling and its punctate co-localization with GCα, the molecular activity of GEP1 itself and the structural basis of the GEP1–GCα interaction have not been characterized in the available corpus.","teleology":[{"year":2020,"claim":"It was unknown what factor licenses gametocytes to convert the xanthurenic acid activation cue into cGMP signaling; disrupting GEP1 showed it is required for XA-stimulated cGMP synthesis and every downstream cGMP/PKG event, establishing GEP1 as an essential early transducer of gametogenesis.","evidence":"CRISPR/Cas9 functional screen and gene disruption in P. yoelii gametocytes with cGMP, Ca2+, gamete formation, and egress readouts","pmids":["32273496"],"confidence":"High","gaps":["The molecular/enzymatic activity of GEP1 itself was not defined","Whether GEP1 senses XA directly or acts through another sensor was not resolved"],"attribution":[{"species":"Plasmodium yoelii","strain":""}]},{"year":2020,"claim":"To determine how GEP1 connects to cGMP production, co-IP and imaging showed it physically interacts and co-localizes with the guanylyl cyclase GCα in gametocyte puncta, and GCα depletion phenocopied GEP1 loss, placing GEP1 in a complex with or upstream of the cGMP-generating enzyme.","evidence":"Co-immunoprecipitation, immunofluorescence/live imaging, and GCα depletion epistasis in P. yoelii","pmids":["32273496"],"confidence":"High","gaps":["The stoichiometry and structural basis of the GEP1–GCα interaction were not determined","Whether GEP1 regulates GCα catalytic activity directly or its localization/stability was not established"],"attribution":[{"species":"Plasmodium yoelii","strain":""}]},{"year":2025,"claim":"It was unknown whether GEP1's role in the human malaria parasite is limited to XA/cGMP signaling; deleting PfGEP1 blocked both male and female gametogenesis even when cGMP was pharmacologically elevated by Zaprinast, establishing an essential XA-independent function that cannot be bypassed downstream.","evidence":"CRISPR-Cas9 gene deletion in P. falciparum with gametogenesis assays under XA, temperature drop, and Zaprinast treatment","pmids":["41084330"],"confidence":"High","gaps":["The XA-independent step at which GEP1 acts was not molecularly defined","Whether the P. falciparum GEP1–GCα interaction and puncta localization mirror P. yoelii was not tested here"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"The intrinsic biochemical activity of GEP1 and how it mechanistically couples the activation cue to GCα-dependent cGMP production remain unresolved.","evidence":"No discovery in the corpus defines a catalytic, transport, or receptor activity for GEP1 or a structural mechanism for its GCα interaction","pmids":[],"confidence":"High","gaps":["No molecular function assigned to GEP1 beyond its requirement for GCα-dependent signaling","No structure of GEP1 or the GEP1–GCα complex","The XA-independent essential step in P. falciparum is not mechanistically identified"],"attribution":[]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["GEP1–GCα complex (cytoplasmic puncta of male and female gametocytes) [#1]"],"partners":["GCΑ (GUANYLYL CYCLASE ALPHA) [#1]"],"other_free_text":["In P. yoelii, GEP1 is required upstream of XA-stimulated cGMP synthesis and all downstream cGMP/PKG-dependent events (Ca2+ mobilization, gamete formation, egress) [#0].","In P. falciparum, GEP1 is essential for both male and female gametogenesis via an XA-independent step that cannot be rescued by Zaprinast-driven cGMP elevation [#2]."]}},"prefetch_data":{},"corpus_meta":[{"pmid":"32273496","id":"PMC_32273496","title":"An intracellular membrane protein GEP1 regulates xanthurenic acid induced gametogenesis of malaria parasites.","date":"2020","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/32273496","citation_count":45,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["GEP1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"22615315","id":"PMC_22615315","title":"In vitro-reduced susceptibility to artemether in P. falciparum and its association with polymorphisms on transporter genes.","date":"2012","source":"The Journal of infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/22615315","citation_count":24,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PFE0775c"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"41084330","id":"PMC_41084330","title":"Plasmodium falciparum gametogenesis essential protein 1 (GEP1) is a transmission-blocking target.","date":"2025","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/41084330","citation_count":1,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["GEP1","PfGEP1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4360,"output_tokens":1042,"usd":0.014355,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5866,"output_tokens":2336,"usd":0.043865,"stage2_stop_reason":"end_turn"},"total_usd":0.05822,"stage1_batch_id":"msgbatch_01DbiymDmubkPpYvdbAu5a7V","stage2_batch_id":"msgbatch_012TbrWvMRH129T7PQ4SmvrJ","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2020,\n      \"finding\": \"GEP1 is required for xanthurenic acid (XA)-stimulated cGMP synthesis and the subsequent cGMP/PKG-dependent signaling events in gametocytes, including Ca2+ mobilization, gamete formation, and gamete egress from erythrocytes; disruption of GEP1 abolishes all these downstream events.\",\n      \"method\": \"CRISPR/Cas9-based functional screening and gene disruption in Plasmodium yoelii gametocytes, with phenotypic readouts of cGMP levels, Ca2+ mobilization, gamete formation, and egress\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean loss-of-function with multiple orthogonal cellular phenotype readouts (cGMP, Ca2+, gamete formation, egress) in a rigorous CRISPR screen\",\n      \"pmids\": [\"32273496\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium yoelii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"GEP1 physically interacts with GCα (a cGMP-synthesizing guanylyl cyclase) in gametocytes, and both proteins co-localize in cytoplasmic puncta of male and female gametocytes; depletion of GCα mimics the GEP1 disruption phenotype, placing GEP1 upstream of or in complex with GCα in the XA-sensing/transduction pathway.\",\n      \"method\": \"Co-immunoprecipitation (GEP1–GCα interaction), immunofluorescence/live imaging (cytoplasmic puncta localization), and GCα depletion epistasis in Plasmodium yoelii\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal interaction (Co-IP), direct localization experiment, and genetic epistasis in a single rigorous study with multiple orthogonal methods\",\n      \"pmids\": [\"32273496\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium yoelii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"GEP1 is essential for both male and female gametogenesis in Plasmodium falciparum; CRISPR-Cas9-generated PfGEP1 loss-of-function lines completely fail to undergo gametogenesis even upon XA stimulation, temperature drop, or treatment with the phosphodiesterase inhibitor Zaprinast, indicating GEP1 acts at a step that cannot be bypassed by pharmacological elevation of cGMP.\",\n      \"method\": \"CRISPR-Cas9 gene deletion in Plasmodium falciparum with gametogenesis assays under XA stimulation, temperature drop, and Zaprinast treatment\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with multiple stimulation conditions tested, defining an XA-independent essential function in the human malaria parasite\",\n      \"pmids\": [\"41084330\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"GEP1 (PF3D7_0515500) is an intracellular membrane protein expressed in cytoplasmic puncta of both male and female gametocytes that physically interacts with the cGMP-synthesizing enzyme GCα and is required upstream of cGMP production for xanthurenic acid-triggered gametogenesis in Plasmodium yoelii; in Plasmodium falciparum, GEP1 is absolutely essential for gametogenesis through both XA-dependent and XA-independent mechanisms, as its deletion blocks all gamete activation even when cGMP is pharmacologically elevated by Zaprinast.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GEP1 (PF3D7_0515500) is an intracellular membrane protein required for gametogenesis in malaria parasites, acting at the earliest steps of the signaling cascade that converts an environmental activation cue into gamete formation [#0]. In Plasmodium yoelii, GEP1 is essential for xanthurenic acid (XA)-stimulated cGMP synthesis and the downstream cGMP/PKG-dependent events, including Ca2+ mobilization, gamete formation, and gamete egress; its disruption abolishes all of these responses [#0]. Mechanistically, GEP1 physically interacts with the cGMP-synthesizing guanylyl cyclase GCα and co-localizes with it in cytoplasmic puncta of both male and female gametocytes, and GCα depletion phenocopies GEP1 loss, placing GEP1 upstream of or in complex with GCα in the XA-sensing/transduction pathway [#1]. In Plasmodium falciparum, GEP1 is absolutely essential for both male and female gametogenesis: loss-of-function parasites fail to activate under XA, temperature drop, or the phosphodiesterase inhibitor Zaprinast, indicating GEP1 acts at a step that cannot be bypassed by pharmacological elevation of cGMP and defines an XA-independent essential function [#2]. Beyond its requirement for GCα-dependent signaling and its punctate co-localization with GCα, the molecular activity of GEP1 itself and the structural basis of the GEP1–GCα interaction have not been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2020,\n      \"claim\": \"It was unknown what factor licenses gametocytes to convert the xanthurenic acid activation cue into cGMP signaling; disrupting GEP1 showed it is required for XA-stimulated cGMP synthesis and every downstream cGMP/PKG event, establishing GEP1 as an essential early transducer of gametogenesis.\",\n      \"evidence\": \"CRISPR/Cas9 functional screen and gene disruption in P. yoelii gametocytes with cGMP, Ca2+, gamete formation, and egress readouts\",\n      \"pmids\": [\n        \"32273496\"\n      ],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The molecular/enzymatic activity of GEP1 itself was not defined\",\n        \"Whether GEP1 senses XA directly or acts through another sensor was not resolved\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Plasmodium yoelii\",\n          \"strain\": \"\"\n        }\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"To determine how GEP1 connects to cGMP production, co-IP and imaging showed it physically interacts and co-localizes with the guanylyl cyclase GCα in gametocyte puncta, and GCα depletion phenocopied GEP1 loss, placing GEP1 in a complex with or upstream of the cGMP-generating enzyme.\",\n      \"evidence\": \"Co-immunoprecipitation, immunofluorescence/live imaging, and GCα depletion epistasis in P. yoelii\",\n      \"pmids\": [\n        \"32273496\"\n      ],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The stoichiometry and structural basis of the GEP1–GCα interaction were not determined\",\n        \"Whether GEP1 regulates GCα catalytic activity directly or its localization/stability was not established\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Plasmodium yoelii\",\n          \"strain\": \"\"\n        }\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"It was unknown whether GEP1's role in the human malaria parasite is limited to XA/cGMP signaling; deleting PfGEP1 blocked both male and female gametogenesis even when cGMP was pharmacologically elevated by Zaprinast, establishing an essential XA-independent function that cannot be bypassed downstream.\",\n      \"evidence\": \"CRISPR-Cas9 gene deletion in P. falciparum with gametogenesis assays under XA, temperature drop, and Zaprinast treatment\",\n      \"pmids\": [\n        \"41084330\"\n      ],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The XA-independent step at which GEP1 acts was not molecularly defined\",\n        \"Whether the P. falciparum GEP1–GCα interaction and puncta localization mirror P. yoelii was not tested here\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Plasmodium falciparum\",\n          \"strain\": \"\"\n        }\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The intrinsic biochemical activity of GEP1 and how it mechanistically couples the activation cue to GCα-dependent cGMP production remain unresolved.\",\n      \"evidence\": \"No discovery in the corpus defines a catalytic, transport, or receptor activity for GEP1 or a structural mechanism for its GCα interaction\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No molecular function assigned to GEP1 beyond its requirement for GCα-dependent signaling\",\n        \"No structure of GEP1 or the GEP1–GCα complex\",\n        \"The XA-independent essential step in P. falciparum is not mechanistically identified\"\n      ],\n      \"attribution\": []\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\n        \"term_id\": \"GO:0005737\",\n        \"supporting_discovery_ids\": [\n          1\n        ]\n      },\n      {\n        \"term_id\": \"GO:0016020\",\n        \"supporting_discovery_ids\": [\n          1\n        ]\n      }\n    ],\n    \"pathway\": [\n      {\n        \"term_id\": \"GO:0006182\",\n        \"supporting_discovery_ids\": [\n          0\n        ]\n      },\n      {\n        \"term_id\": \"GO:0007276\",\n        \"supporting_discovery_ids\": [\n          0,\n          2\n        ]\n      }\n    ],\n    \"complexes\": [\n      \"GEP1–GCα complex (cytoplasmic puncta of male and female gametocytes) [#1]\"\n    ],\n    \"partners\": [\n      \"GCα (guanylyl cyclase alpha) [#1]\"\n    ],\n    \"other_free_text\": [\n      \"In P. yoelii, GEP1 is required upstream of XA-stimulated cGMP synthesis and all downstream cGMP/PKG-dependent events (Ca2+ mobilization, gamete formation, egress) [#0].\",\n      \"In P. falciparum, GEP1 is essential for both male and female gametogenesis via an XA-independent step that cannot be rescued by Zaprinast-driven cGMP elevation [#2].\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_0515500","name":null,"product":"gametogenesis essential protein 1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_1115100","name":null,"product":"gametogenesis essential protein 1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_1017700","name":null,"product":"gametogenesis essential protein 1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"GEP1","evaluation":null}