{"gene":"PF3D7_0317500","run_date":"2026-09-07T10:55:51","timeline":{"discoveries":[{"year":2020,"finding":"In P. berghei, EG5 (kinesin-5) localizes to the spindle apparatus and spindle poles during both atypical mitosis and meiosis, co-localizing with α-tubulin and centrin-2, with partial overlap with kinetochore marker NDC80 during blood-stage schizogony; it is closely associated with NDC80 during male gametogony but not with kinesin-8B (basal body/axoneme marker). Deletion of kinesin-5 caused a significant decrease in motile sporozoite production in oocysts without visible defects at other proliferative stages.","method":"Live-cell imaging (GFP tagging), fixed-cell immunofluorescence, dual-color live imaging, microtubule inhibitor treatment, and gene deletion (loss-of-function)","journal":"Frontiers in cellular and infection microbiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (live imaging, IFA, drug treatment, genetic KO) with clear functional phenotype in a single rigorous study","pmids":["33154955"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2021,"finding":"Cryo-EM structure of P. falciparum EG5 (PfK5) motor domain bound to microtubules shows classical kinesin mechanochemistry including ATP-induced subdomain rearrangement and cover-neck bundle formation consistent with plus-end-directed motility; an insertion in loop5 of the PfK5 motor domain creates a structurally distinct environment at the established human kinesin-5 drug-binding site, indicating potential for selective inhibition.","method":"Cryo-EM structure determination of microtubule-bound motor domain with nucleotide-dependent 3D classification","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cryo-EM structural determination with nucleotide-state analysis; single lab but rigorous structural method with direct mechanistic insight","pmids":["34375637"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2014,"finding":"P. falciparum and P. vivax EG5 (kinesin-5) motor domains possess ATPase activity that can be selectively inhibited by small molecules; compound MMV666693 was identified as a selective allosteric inhibitor of Plasmodium EG5 that does not compete with ATP at the conserved active site and does not disrupt the microtubule-binding site, acting through a distinct allosteric mechanism.","method":"Small-molecule ATPase activity screen (~2000 compounds) with parallel human kinesin-5 counter-screen and substrate-competition biochemical assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro enzymatic ATPase assay with competition experiments establishing allosteric mechanism; single lab, biochemical only","pmids":["24737313"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium vivax","strain":""}]}],"current_model":"Plasmodium EG5 (PF3D7_0317500) is a plus-end-directed microtubule motor that localizes to the spindle apparatus and spindle poles during mitosis and meiosis, is required for efficient infectious sporozoite production in oocysts, exhibits classical kinesin mechanochemistry (ATP-induced subdomain rearrangement, cover-neck bundle formation), and harbors a loop5 insertion that creates an allosteric drug-binding site distinct from human kinesin-5, enabling selective inhibition by compounds such as MMV666693."},"narrative":{"mechanistic_narrative":"EG5 (PF3D7_0317500) is a plus-end-directed kinesin-5 microtubule motor that operates during the atypical cell divisions of the Plasmodium life cycle. In P. berghei, EG5 localizes to the spindle apparatus and spindle poles during both atypical mitosis and meiosis, co-localizing with α-tubulin and centrin-2 and partially overlapping with the kinetochore marker NDC80 during blood-stage schizogony, with close association with NDC80 during male gametogony but not with the basal body/axoneme marker kinesin-8B; genetic deletion selectively reduces motile sporozoite production in oocysts without visible defects at other proliferative stages, defining a stage-specific requirement in the mosquito phase [PMID:33154955]. Cryo-EM of the P. falciparum EG5 motor domain bound to microtubules establishes that it uses classical kinesin mechanochemistry, including ATP-induced subdomain rearrangement and cover-neck bundle formation consistent with plus-end-directed motility [PMID:34375637]. The purified P. falciparum and P. vivax motor domains possess ATPase activity, and a loop5 insertion in the motor domain creates a structurally distinct environment at the human kinesin-5 drug-binding site that supports selective allosteric inhibition—exemplified by MMV666693, which inhibits Plasmodium EG5 without competing at the ATP site or disrupting microtubule binding [PMID:34375637, PMID:24737313].","teleology":[{"year":2014,"claim":"To test whether Plasmodium EG5 is a druggable target distinct from its human counterpart, its motor-domain ATPase was screened against small molecules, establishing that a selective allosteric inhibitor could act without competing at the conserved ATP or microtubule sites.","evidence":"Small-molecule ATPase screen of ~2000 compounds with parallel human kinesin-5 counter-screen and substrate-competition assays using P. falciparum and P. vivax motor domains","pmids":["24737313"],"confidence":"Medium","gaps":["In vitro enzymatic assay only; no cellular validation that MMV666693 inhibits parasite EG5 in situ","Structural basis of the allosteric site not defined by this biochemical study","No demonstration of anti-parasitic activity or selectivity margin in living parasites"],"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium vivax","strain":""}]},{"year":2020,"claim":"To determine where and when EG5 acts in the parasite, its subcellular localization was mapped across proliferative stages and the gene was deleted, establishing it as a spindle/spindle-pole motor with a stage-specific requirement for sporozoite production.","evidence":"Live-cell GFP imaging, fixed-cell IFA, dual-color live imaging with tubulin/centrin/NDC80/kinesin-8B markers, microtubule inhibitor treatment, and gene deletion in P. berghei","pmids":["33154955"],"confidence":"High","gaps":["Molecular mechanism linking spindle-pole localization to sporozoite motility not resolved","Why deletion affects oocyst-stage sporozoites but not other proliferative stages is unexplained","Direct interaction partners at the spindle not biochemically identified"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2021,"claim":"To explain how EG5 generates force and how it could be selectively targeted, its microtubule-bound motor domain was solved by cryo-EM, revealing conserved kinesin mechanochemistry and a loop5 insertion that structurally distinguishes the Plasmodium drug-binding site.","evidence":"Cryo-EM structure determination of the microtubule-bound P. falciparum motor domain with nucleotide-dependent 3D classification","pmids":["34375637"],"confidence":"High","gaps":["No co-structure with an inhibitor such as MMV666693 bound at the loop5 site","Structure limited to the isolated motor domain; full-length motor architecture and oligomerization not addressed","Motility parameters (velocity, processivity) not measured"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"The mechanistic chain connecting EG5 spindle motor activity to infectious sporozoite formation, and validation of allosteric inhibitors against parasites in the mosquito stage, remains open.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No cellular or in vivo proof that inhibiting EG5 ATPase blocks sporozoite production","Spindle interactome and regulation of EG5 recruitment not characterized","Species-specific differences between P. berghei function and P. falciparum/P. vivax biochemistry not reconciled"],"attribution":[]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":[],"other_free_text":["In P. berghei, EG5 co-localizes with α-tubulin and centrin-2 and partially overlaps with the kinetochore marker NDC80, but is not associated with the basal body/axoneme marker kinesin-8B [#0].","Deletion of EG5 in P. berghei selectively reduces motile sporozoite production in oocysts without visible defects at other proliferative stages [#0].","A loop5 insertion in the P. falciparum EG5 motor domain creates a drug-binding environment distinct from human kinesin-5, supporting selective allosteric inhibition [#1, #2].","MMV666693 is a selective allosteric inhibitor of Plasmodium EG5 ATPase that does not compete at the ATP site or disrupt microtubule binding [#2]."]}},"prefetch_data":{},"corpus_meta":[{"pmid":"33154955","id":"PMC_33154955","title":"Plasmodium berghei Kinesin-5 Associates With the Spindle Apparatus During Cell Division and Is Important for Efficient Production of Infectious Sporozoites.","date":"2020","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/33154955","citation_count":18,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["EG5","kinesin-5"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"34375637","id":"PMC_34375637","title":"Cryo-EM structure of a microtubule-bound parasite kinesin motor and implications for its mechanism and inhibition.","date":"2021","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/34375637","citation_count":15,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["kinesin-5"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"24737313","id":"PMC_24737313","title":"Small molecule screen for candidate antimalarials targeting Plasmodium Kinesin-5.","date":"2014","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24737313","citation_count":14,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["kinesin-5"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4343,"output_tokens":1074,"usd":0.01457,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5878,"output_tokens":2564,"usd":0.046745,"stage2_stop_reason":"end_turn"},"total_usd":0.061315,"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\": \"In P. berghei, EG5 (kinesin-5) localizes to the spindle apparatus and spindle poles during both atypical mitosis and meiosis, co-localizing with α-tubulin and centrin-2, with partial overlap with kinetochore marker NDC80 during blood-stage schizogony; it is closely associated with NDC80 during male gametogony but not with kinesin-8B (basal body/axoneme marker). Deletion of kinesin-5 caused a significant decrease in motile sporozoite production in oocysts without visible defects at other proliferative stages.\",\n      \"method\": \"Live-cell imaging (GFP tagging), fixed-cell immunofluorescence, dual-color live imaging, microtubule inhibitor treatment, and gene deletion (loss-of-function)\",\n      \"journal\": \"Frontiers in cellular and infection microbiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (live imaging, IFA, drug treatment, genetic KO) with clear functional phenotype in a single rigorous study\",\n      \"pmids\": [\"33154955\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Cryo-EM structure of P. falciparum EG5 (PfK5) motor domain bound to microtubules shows classical kinesin mechanochemistry including ATP-induced subdomain rearrangement and cover-neck bundle formation consistent with plus-end-directed motility; an insertion in loop5 of the PfK5 motor domain creates a structurally distinct environment at the established human kinesin-5 drug-binding site, indicating potential for selective inhibition.\",\n      \"method\": \"Cryo-EM structure determination of microtubule-bound motor domain with nucleotide-dependent 3D classification\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cryo-EM structural determination with nucleotide-state analysis; single lab but rigorous structural method with direct mechanistic insight\",\n      \"pmids\": [\"34375637\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"P. falciparum and P. vivax EG5 (kinesin-5) motor domains possess ATPase activity that can be selectively inhibited by small molecules; compound MMV666693 was identified as a selective allosteric inhibitor of Plasmodium EG5 that does not compete with ATP at the conserved active site and does not disrupt the microtubule-binding site, acting through a distinct allosteric mechanism.\",\n      \"method\": \"Small-molecule ATPase activity screen (~2000 compounds) with parallel human kinesin-5 counter-screen and substrate-competition biochemical assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro enzymatic ATPase assay with competition experiments establishing allosteric mechanism; single lab, biochemical only\",\n      \"pmids\": [\"24737313\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium vivax\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"Plasmodium EG5 (PF3D7_0317500) is a plus-end-directed microtubule motor that localizes to the spindle apparatus and spindle poles during mitosis and meiosis, is required for efficient infectious sporozoite production in oocysts, exhibits classical kinesin mechanochemistry (ATP-induced subdomain rearrangement, cover-neck bundle formation), and harbors a loop5 insertion that creates an allosteric drug-binding site distinct from human kinesin-5, enabling selective inhibition by compounds such as MMV666693.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"EG5 (PF3D7_0317500) is a plus-end-directed kinesin-5 microtubule motor that operates during the atypical cell divisions of the Plasmodium life cycle. In P. berghei, EG5 localizes to the spindle apparatus and spindle poles during both atypical mitosis and meiosis, co-localizing with \\u03b1-tubulin and centrin-2 and partially overlapping with the kinetochore marker NDC80 during blood-stage schizogony, with close association with NDC80 during male gametogony but not with the basal body/axoneme marker kinesin-8B; genetic deletion selectively reduces motile sporozoite production in oocysts without visible defects at other proliferative stages, defining a stage-specific requirement in the mosquito phase [#0]. Cryo-EM of the P. falciparum EG5 motor domain bound to microtubules establishes that it uses classical kinesin mechanochemistry, including ATP-induced subdomain rearrangement and cover-neck bundle formation consistent with plus-end-directed motility [#1]. The purified P. falciparum and P. vivax motor domains possess ATPase activity, and a loop5 insertion in the motor domain creates a structurally distinct environment at the human kinesin-5 drug-binding site that supports selective allosteric inhibition\\u2014exemplified by MMV666693, which inhibits Plasmodium EG5 without competing at the ATP site or disrupting microtubule binding [#1, #2].\",\n  \"teleology\": [\n    {\n      \"year\": 2014,\n      \"claim\": \"To test whether Plasmodium EG5 is a druggable target distinct from its human counterpart, its motor-domain ATPase was screened against small molecules, establishing that a selective allosteric inhibitor could act without competing at the conserved ATP or microtubule sites.\",\n      \"evidence\": \"Small-molecule ATPase screen of ~2000 compounds with parallel human kinesin-5 counter-screen and substrate-competition assays using P. falciparum and P. vivax motor domains\",\n      \"pmids\": [\"24737313\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"In vitro enzymatic assay only; no cellular validation that MMV666693 inhibits parasite EG5 in situ\",\n        \"Structural basis of the allosteric site not defined by this biochemical study\",\n        \"No demonstration of anti-parasitic activity or selectivity margin in living parasites\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium vivax\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"To determine where and when EG5 acts in the parasite, its subcellular localization was mapped across proliferative stages and the gene was deleted, establishing it as a spindle/spindle-pole motor with a stage-specific requirement for sporozoite production.\",\n      \"evidence\": \"Live-cell GFP imaging, fixed-cell IFA, dual-color live imaging with tubulin/centrin/NDC80/kinesin-8B markers, microtubule inhibitor treatment, and gene deletion in P. berghei\",\n      \"pmids\": [\"33154955\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Molecular mechanism linking spindle-pole localization to sporozoite motility not resolved\",\n        \"Why deletion affects oocyst-stage sporozoites but not other proliferative stages is unexplained\",\n        \"Direct interaction partners at the spindle not biochemically identified\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"To explain how EG5 generates force and how it could be selectively targeted, its microtubule-bound motor domain was solved by cryo-EM, revealing conserved kinesin mechanochemistry and a loop5 insertion that structurally distinguishes the Plasmodium drug-binding site.\",\n      \"evidence\": \"Cryo-EM structure determination of the microtubule-bound P. falciparum motor domain with nucleotide-dependent 3D classification\",\n      \"pmids\": [\"34375637\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"No co-structure with an inhibitor such as MMV666693 bound at the loop5 site\",\n        \"Structure limited to the isolated motor domain; full-length motor architecture and oligomerization not addressed\",\n        \"Motility parameters (velocity, processivity) not measured\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The mechanistic chain connecting EG5 spindle motor activity to infectious sporozoite formation, and validation of allosteric inhibitors against parasites in the mosquito stage, remains open.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"No cellular or in vivo proof that inhibiting EG5 ATPase blocks sporozoite production\",\n        \"Spindle interactome and regulation of EG5 recruitment not characterized\",\n        \"Species-specific differences between P. berghei function and P. falciparum/P. vivax biochemistry not reconciled\"\n      ],\n      \"attribution\": []\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008574\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0003777\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0016887\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0008017\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005819\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0000922\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0007067\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0007127\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0007059\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [],\n    \"partners\": [],\n    \"other_free_text\": [\n      \"In P. berghei, EG5 co-localizes with \\u03b1-tubulin and centrin-2 and partially overlaps with the kinetochore marker NDC80, but is not associated with the basal body/axoneme marker kinesin-8B [#0].\",\n      \"Deletion of EG5 in P. berghei selectively reduces motile sporozoite production in oocysts without visible defects at other proliferative stages [#0].\",\n      \"A loop5 insertion in the P. falciparum EG5 motor domain creates a drug-binding environment distinct from human kinesin-5, supporting selective allosteric inhibition [#1, #2].\",\n      \"MMV666693 is a selective allosteric inhibitor of Plasmodium EG5 ATPase that does not compete at the ATP site or disrupt microtubule binding [#2].\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_0317500","name":null,"product":"kinesin-5","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_0807700","name":null,"product":"kinesin-5","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_0824300","name":null,"product":"kinesin-5, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"EG5","evaluation":null}