{"gene":"TG_243250","gene_symbol":"","run_date":"2026-09-10T21:09:19","timeline":{"discoveries":[{"year":2016,"finding":"MyoH (TGME49_243250) is anchored to the conoid via three alpha-tubulin suppressor (ATS) domains located in its tail; conditional disruption of TgMyoH severely compromises parasite motility, invasion, and egress, and MyoH is required for translocation of the circular junction from the parasite tip to the apical position where the IMC starts, establishing the first step of force generation along the conoid before relay by MyoA.","method":"Conditional gene disruption (TetO system), domain-deletion constructs, live imaging of gliding/invasion/egress, immunofluorescence assay","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional KO with multiple orthogonal phenotypic readouts (motility, invasion, egress, junction translocation), domain-deletion mapping of ATS anchor, replicated in peer-reviewed study","pmids":["26760042"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"Calmodulin-like proteins CaM1, CaM2, and CaM3 co-localize with MyoH (TGME49_243250) at the conoid; proximity biotinylation (BirA fusions to the CaMs) labels MyoH and its light chain MLC7, suggesting physical association; disruption of MyoH leads to degradation of CaM3 or redistribution of CaM1/CaM2, indicating MyoH is required for stable conoid association of these CaMs.","method":"Super-resolution microscopy (localization), BirA proximity biotinylation, auxin-induced degron (AID) knockdown of MyoH, immunofluorescence","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — proximity labeling (not co-IP) and epistatic degradation/redistribution observed in single lab with two orthogonal methods; interaction inferred, not directly confirmed by pulldown","pmids":["28475612"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2022,"finding":"MyoH (TGME49_243250) uses F-actin produced by Formin1 at the preconoidal rings to generate the mechanical force for conoid extrusion; conoid extrusion in turn directs F-actin flux to the pellicular space, thereby controlling the assembly of the MyoA-glideosome and gating parasite motility.","method":"Ultrastructure expansion microscopy (U-ExM), conditional knockdown/disruption of preconoidal ring components and Formin1, live and fixed imaging of conoid extrusion and actin dynamics","journal":"Nature microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis and U-ExM in single lab; MyoH functional role in conoid extrusion inferred from pathway context with Formin1 and PCR mutants rather than direct MyoH manipulation in this paper","pmids":["36109645"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2026,"finding":"3D single-molecule super-resolution microscopy (SMLM) of N- and C-terminally labeled MyoH (TGME49_243250) in fixed parasites established that the motor head is radially exterior to the tail within the apical complex, and that the tail faces the interior of the conoid barrel while the motor head faces the exterior.","method":"3D single-molecule localization microscopy (PALM/STORM) in fixed and gel-expanded parasites, two-color imaging with tubulin","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — high-resolution structural localization method with orthogonal labeling strategies, but preprint (not peer-reviewed) and single lab","pmids":["42094507"],"is_preprint":true,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"MyoH (TGME49_243250) is a class XIV myosin anchored to the interior face of the conoid barrel via ATS domains in its tail, with its motor head projecting to the conoid exterior; it uses Formin1-generated F-actin to power conoid extrusion, translates the secretory circular junction from the parasite tip to the IMC boundary to initiate the first step of gliding motility, and associates with calmodulin-like light chains (CaM1–3 and MLC7) that stabilize its conoid localization—functions indispensable for parasite motility, host-cell invasion, and egress."},"narrative":{"mechanistic_narrative":"MyoH (TGME49_243250) is a conoid-anchored motor that powers the first step of the mechanical cascade driving Toxoplasma gondii gliding motility, host-cell invasion, and egress [PMID:26760042]. It is tethered to the conoid through three alpha-tubulin suppressor (ATS) domains in its tail, with the tail facing the interior of the conoid barrel and the motor head projecting radially to the exterior of the apical complex [PMID:26760042, PMID:42094507]. MyoH drives conoid extrusion using F-actin generated by Formin1 at the preconoidal rings, and this extrusion directs actin flux into the pellicular space to gate assembly of the MyoA glideosome—positioning MyoH upstream of MyoA in force generation and translocating the circular junction from the parasite tip to the apical position where the IMC begins [PMID:26760042, PMID:36109645]. Its stable conoid localization is coupled to associated calmodulin-like light chains: MyoH co-localizes with CaM1–CaM3 and its light chain MLC7, and its loss causes CaM3 degradation and CaM1/CaM2 redistribution, indicating MyoH is required for their conoid association [PMID:28475612].","teleology":[{"year":2016,"claim":"Established that MyoH is a distinct conoid-anchored motor essential for the initiating step of force generation, resolving how motility begins upstream of the known MyoA glideosome.","evidence":"Conditional TetO disruption with domain-deletion mapping and live imaging of motility, invasion, egress, and junction translocation in T. gondii","pmids":["26760042"],"confidence":"High","gaps":["Direct force measurement of MyoH motor activity not performed","Actin substrate for MyoH not identified in this study","Mechanism of ATS-domain conoid anchoring not resolved structurally"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"Addressed which light chains stabilize MyoH by showing calmodulin-like proteins associate with and depend on MyoH for conoid localization.","evidence":"Super-resolution microscopy, BirA proximity biotinylation, and AID knockdown of MyoH in T. gondii","pmids":["28475612"],"confidence":"Medium","gaps":["Interaction inferred from proximity labeling, not confirmed by co-IP/pulldown","Functional consequence of each CaM for MyoH motor activity not dissected","Stoichiometry of CaM/MLC7 binding to MyoH unknown"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2022,"claim":"Placed MyoH in a mechanistic pathway by linking Formin1-generated F-actin to conoid extrusion and downstream MyoA-glideosome gating.","evidence":"U-ExM and conditional knockdown of preconoidal ring components and Formin1 with imaging of conoid extrusion and actin dynamics in T. gondii","pmids":["36109645"],"confidence":"Medium","gaps":["MyoH role inferred from pathway context rather than direct MyoH manipulation in this study","Quantitative contribution of MyoH versus other factors to extrusion force not measured","Regulation coupling extrusion to actin flux not defined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2026,"claim":"Resolved the spatial orientation of MyoH within the apical complex, showing tail-interior/head-exterior topology consistent with an outward-projecting motor.","evidence":"3D single-molecule localization microscopy of N- and C-terminally labeled MyoH with two-color tubulin imaging in fixed/gel-expanded parasites (preprint)","pmids":["42094507"],"confidence":"Medium","gaps":["Preprint, not peer-reviewed","Single lab","Does not resolve how head orientation couples to F-actin engagement during extrusion"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["MyoH–CaM1/CaM2/CaM3–MLC7 conoid motor complex (inferred from proximity labeling)"],"partners":["CAM1","CAM2","CAM3","MLC7","FORMIN1 (FUNCTIONAL/PATHWAY LINK)","MYOA (DOWNSTREAM RELAY)"],"other_free_text":["Tail anchored via three ATS domains to the interior of the conoid barrel; motor head projects to the conoid/apical-complex exterior [#0, #3].","Powers conoid extrusion using Formin1-generated F-actin at the preconoidal rings, gating MyoA-glideosome assembly and initiating gliding [#2].","Required for translocation of the circular junction from the parasite tip to the apical IMC boundary [#0]."]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"28475612","id":"PMC_28475612","title":"Calmodulin-like proteins localized to the conoid regulate motility and cell invasion by Toxoplasma gondii.","date":"2017","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/28475612","citation_count":84,"is_preprint":false},{"pmid":"26760042","id":"PMC_26760042","title":"The Conoid Associated Motor MyoH Is Indispensable for Toxoplasma gondii Entry and Exit from Host Cells.","date":"2016","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/26760042","citation_count":75,"is_preprint":false},{"pmid":"36109645","id":"PMC_36109645","title":"Conoid extrusion regulates glideosome assembly to control motility and invasion in Apicomplexa.","date":"2022","source":"Nature microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/36109645","citation_count":37,"is_preprint":false},{"pmid":"42094507","id":"PMC_42094507","title":"Organization of Myosin H in the Apical Complex of Toxoplasma Gondii Revealed by 3D Single-Molecule Super-Resolution Microscopy.","date":"2026","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/42094507","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4259,"output_tokens":1687,"usd":0.019041,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6883,"output_tokens":2799,"usd":0.052195,"stage2_stop_reason":"end_turn"},"total_usd":0.135008,"stage1_batch_id":"msgbatch_01TEPNZ4MCzJ7xtsNwosiDRk","stage2_batch_id":"msgbatch_01FQShM7n1sfCr4pWTDShmki","note":"batch pricing = 50% of standard","corrective_rerun":"2026-09-10 wrong-gene rerun (round-4 rules)","corrective_reason":"re-read with subject anchor"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2016,\n      \"finding\": \"MyoH (TGME49_243250) is anchored to the conoid via three alpha-tubulin suppressor (ATS) domains located in its tail; conditional disruption of TgMyoH severely compromises parasite motility, invasion, and egress, and MyoH is required for translocation of the circular junction from the parasite tip to the apical position where the IMC starts, establishing the first step of force generation along the conoid before relay by MyoA.\",\n      \"method\": \"Conditional gene disruption (TetO system), domain-deletion constructs, live imaging of gliding/invasion/egress, immunofluorescence assay\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional KO with multiple orthogonal phenotypic readouts (motility, invasion, egress, junction translocation), domain-deletion mapping of ATS anchor, replicated in peer-reviewed study\",\n      \"pmids\": [\"26760042\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Calmodulin-like proteins CaM1, CaM2, and CaM3 co-localize with MyoH (TGME49_243250) at the conoid; proximity biotinylation (BirA fusions to the CaMs) labels MyoH and its light chain MLC7, suggesting physical association; disruption of MyoH leads to degradation of CaM3 or redistribution of CaM1/CaM2, indicating MyoH is required for stable conoid association of these CaMs.\",\n      \"method\": \"Super-resolution microscopy (localization), BirA proximity biotinylation, auxin-induced degron (AID) knockdown of MyoH, immunofluorescence\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — proximity labeling (not co-IP) and epistatic degradation/redistribution observed in single lab with two orthogonal methods; interaction inferred, not directly confirmed by pulldown\",\n      \"pmids\": [\"28475612\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"MyoH (TGME49_243250) uses F-actin produced by Formin1 at the preconoidal rings to generate the mechanical force for conoid extrusion; conoid extrusion in turn directs F-actin flux to the pellicular space, thereby controlling the assembly of the MyoA-glideosome and gating parasite motility.\",\n      \"method\": \"Ultrastructure expansion microscopy (U-ExM), conditional knockdown/disruption of preconoidal ring components and Formin1, live and fixed imaging of conoid extrusion and actin dynamics\",\n      \"journal\": \"Nature microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis and U-ExM in single lab; MyoH functional role in conoid extrusion inferred from pathway context with Formin1 and PCR mutants rather than direct MyoH manipulation in this paper\",\n      \"pmids\": [\"36109645\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"3D single-molecule super-resolution microscopy (SMLM) of N- and C-terminally labeled MyoH (TGME49_243250) in fixed parasites established that the motor head is radially exterior to the tail within the apical complex, and that the tail faces the interior of the conoid barrel while the motor head faces the exterior.\",\n      \"method\": \"3D single-molecule localization microscopy (PALM/STORM) in fixed and gel-expanded parasites, two-color imaging with tubulin\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — high-resolution structural localization method with orthogonal labeling strategies, but preprint (not peer-reviewed) and single lab\",\n      \"pmids\": [\"42094507\"],\n      \"is_preprint\": true,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"MyoH (TGME49_243250) is a class XIV myosin anchored to the interior face of the conoid barrel via ATS domains in its tail, with its motor head projecting to the conoid exterior; it uses Formin1-generated F-actin to power conoid extrusion, translates the secretory circular junction from the parasite tip to the IMC boundary to initiate the first step of gliding motility, and associates with calmodulin-like light chains (CaM1–3 and MLC7) that stabilize its conoid localization—functions indispensable for parasite motility, host-cell invasion, and egress.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"MyoH (TGME49_243250) is a conoid-anchored motor that powers the first step of the mechanical cascade driving Toxoplasma gondii gliding motility, host-cell invasion, and egress [#0]. It is tethered to the conoid through three alpha-tubulin suppressor (ATS) domains in its tail, with the tail facing the interior of the conoid barrel and the motor head projecting radially to the exterior of the apical complex [#0, #3]. MyoH drives conoid extrusion using F-actin generated by Formin1 at the preconoidal rings, and this extrusion directs actin flux into the pellicular space to gate assembly of the MyoA glideosome—positioning MyoH upstream of MyoA in force generation and translocating the circular junction from the parasite tip to the apical position where the IMC begins [#0, #2]. Its stable conoid localization is coupled to associated calmodulin-like light chains: MyoH co-localizes with CaM1–CaM3 and its light chain MLC7, and its loss causes CaM3 degradation and CaM1/CaM2 redistribution, indicating MyoH is required for their conoid association [#1].\",\n  \"teleology\": [\n    {\n      \"year\": 2016,\n      \"claim\": \"Established that MyoH is a distinct conoid-anchored motor essential for the initiating step of force generation, resolving how motility begins upstream of the known MyoA glideosome.\",\n      \"evidence\": \"Conditional TetO disruption with domain-deletion mapping and live imaging of motility, invasion, egress, and junction translocation in T. gondii\",\n      \"pmids\": [\"26760042\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct force measurement of MyoH motor activity not performed\", \"Actin substrate for MyoH not identified in this study\", \"Mechanism of ATS-domain conoid anchoring not resolved structurally\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Addressed which light chains stabilize MyoH by showing calmodulin-like proteins associate with and depend on MyoH for conoid localization.\",\n      \"evidence\": \"Super-resolution microscopy, BirA proximity biotinylation, and AID knockdown of MyoH in T. gondii\",\n      \"pmids\": [\"28475612\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Interaction inferred from proximity labeling, not confirmed by co-IP/pulldown\", \"Functional consequence of each CaM for MyoH motor activity not dissected\", \"Stoichiometry of CaM/MLC7 binding to MyoH unknown\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed MyoH in a mechanistic pathway by linking Formin1-generated F-actin to conoid extrusion and downstream MyoA-glideosome gating.\",\n      \"evidence\": \"U-ExM and conditional knockdown of preconoidal ring components and Formin1 with imaging of conoid extrusion and actin dynamics in T. gondii\",\n      \"pmids\": [\"36109645\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"MyoH role inferred from pathway context rather than direct MyoH manipulation in this study\", \"Quantitative contribution of MyoH versus other factors to extrusion force not measured\", \"Regulation coupling extrusion to actin flux not defined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Resolved the spatial orientation of MyoH within the apical complex, showing tail-interior/head-exterior topology consistent with an outward-projecting motor.\",\n      \"evidence\": \"3D single-molecule localization microscopy of N- and C-terminally labeled MyoH with two-color tubulin imaging in fixed/gel-expanded parasites (preprint)\",\n      \"pmids\": [\"42094507\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not peer-reviewed\", \"Single lab\", \"Does not resolve how head orientation couples to F-actin engagement during extrusion\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How MyoH motor activity is biochemically regulated and directly coupled to Formin1-derived F-actin to produce conoid extrusion force remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct biochemical/motility assay of MyoH ATPase or actin-dependent force\", \"No structure of the ATS-anchored MyoH–light-chain complex\", \"Direct physical MyoH–CaM interaction not confirmed by pulldown\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003774\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0051015\", \"supporting_discovery_ids\": [2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0020015\", \"supporting_discovery_ids\": [0, 1, 3], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0044599\", \"supporting_discovery_ids\": [0, 1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0071965\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0044409\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [\"MyoH–CaM1/CaM2/CaM3–MLC7 conoid motor complex (inferred from proximity labeling)\"],\n    \"partners\": [\"CaM1\", \"CaM2\", \"CaM3\", \"MLC7\", \"Formin1 (functional/pathway link)\", \"MyoA (downstream relay)\"],\n    \"other_free_text\": [\n      \"Tail anchored via three ATS domains to the interior of the conoid barrel; motor head projects to the conoid/apical-complex exterior [#0, #3].\",\n      \"Powers conoid extrusion using Formin1-generated F-actin at the preconoidal rings, gating MyoA-glideosome assembly and initiating gliding [#2].\",\n      \"Required for translocation of the circular junction from the parasite tip to the apical IMC boundary [#0].\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_243250","name":null,"product":"myosin H","uniprot_acc":"A0A125YQD4","chromosome":"TGME49_chrVI","start_pos":2460908},{"strain":"GT1","gene_id":"TGGT1_243250","name":null,"product":"myosin H","uniprot_acc":null,"chromosome":"TGGT1_chrVI","start_pos":2380998},{"strain":"RH88","gene_id":"TGRH88_029160","name":null,"product":"myosin H","uniprot_acc":null,"chromosome":"CM023087","start_pos":1236751},{"strain":"VEG","gene_id":"TGVEG_243250","name":null,"product":"myosin H","uniprot_acc":"B9PP83","chromosome":"TGVEG_chrVI","start_pos":2464608}]}