{"gene":"TG_246930","gene_symbol":"CAM1","run_date":"2026-09-08T15:31:36+00:00","timeline":{"discoveries":[{"year":2017,"finding":"CaM1 and CaM2 are individually dispensable but their combined loss results in a synthetic lethal phenotype, placing both proteins in an essential redundant pathway in Toxoplasma gondii.","method":"CRISPR/Cas9-mediated gene editing (double knockout)","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean genetic knockout with defined lethal phenotype, two orthogonal genetic tools (CRISPR + AID) in a single study","pmids":["28475612"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"CaM1 localizes to the conoid at the apical tip of the parasite, where it overlaps spatially with myosin H (MyoH).","method":"Super-resolution microscopy","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct super-resolution imaging, single lab but rigorous localization method","pmids":["28475612"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"CaM1 contributes to parasite motility, invasion, and egress from host cells, acting downstream of microneme and rhoptry secretion.","method":"Auxin-induced degron (AID) system combined with phenotypic assays (motility, invasion, egress)","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — AID-based depletion with defined phenotypic readouts, but CaM1 was individually dispensable so the specific contribution is inferred from combined loss-of-function context","pmids":["28475612"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"Proximity biotinylation (BirA fusion) with CaM1 labeled apical proteins including MyoH and its light chain MLC7, suggesting a physical association between CaM1 and the MyoH motor complex.","method":"BioID proximity biotinylation (BirA fusion)","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 3 / Weak — proximity labeling is indirect; interaction with MyoH/MLC7 is suggested but not confirmed by reciprocal Co-IP or reconstitution","pmids":["28475612"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"Disruption of MyoH leads to redistribution of CaM1 and CaM2 from the conoid, indicating that MyoH is required for proper conoid localization of CaM1.","method":"Genetic disruption of MyoH followed by immunofluorescence localization of CaM1/CaM2","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — epistasis via genetic disruption with direct localization readout, single lab","pmids":["28475612"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"CAM1 is a calmodulin-like protein that localizes to the Toxoplasma gondii conoid, where it acts redundantly with CaM2 (synthetic lethality upon double knockout) downstream of microneme and rhoptry secretion to regulate parasite motility, invasion, and egress, likely through a physical or functional interaction with the conoid-resident motor myosin H (MyoH), which in turn is required for correct CaM1 localization."},"narrative":{"mechanistic_narrative":"CAM1 (CaM1) is a calmodulin-like protein of Toxoplasma gondii that localizes to the conoid at the parasite's apical tip and functions in the motility-dependent steps of the lytic cycle [PMID:28475612]. CaM1 and its paralog CaM2 are individually dispensable but their combined loss is synthetic lethal, placing the two in an essential redundant pathway [PMID:28475612]. Depletion of CaM1 impairs parasite motility, host-cell invasion, and egress, and these defects occur downstream of microneme and rhoptry secretion [PMID:28475612]. At the conoid, CaM1 spatially overlaps and physically associates with the conoid-resident motor myosin H (MyoH) and its light chain MLC7 [PMID:28475612], and MyoH is in turn required for correct conoid localization of CaM1, since its disruption redistributes CaM1 away from the apical tip [PMID:28475612]. Beyond this conoid/MyoH-associated role, no further mechanistic detail (biochemical calcium-binding activity, direct substrate or reconstituted interaction) has been characterized in the available corpus.","teleology":[{"year":2017,"claim":"Establishing whether CaM1 is essential resolved why single-gene knockouts had been uninformative: CaM1 and CaM2 act redundantly, so only their combined loss is lethal, defining an essential shared pathway.","evidence":"CRISPR/Cas9 single and double knockouts in T. gondii","pmids":["28475612"],"confidence":"High","gaps":["Does not define which molecular function CaM1 and CaM2 share","Degree of functional interchangeability between the two paralogs not quantified"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"Super-resolution imaging placed CaM1 at the conoid overlapping MyoH, pinpointing the subcellular site where CaM1 acts within the apical motility machinery.","evidence":"Super-resolution microscopy of CaM1 and MyoH in T. gondii","pmids":["28475612"],"confidence":"High","gaps":["Spatial overlap does not prove direct molecular contact","Dynamics of CaM1 recruitment during the lytic cycle not resolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"Phenotypic depletion assays assigned CaM1 to motility, invasion, and egress acting downstream of secretion, distinguishing its role from the upstream microneme/rhoptry discharge machinery.","evidence":"Auxin-induced degron depletion with motility, invasion, and egress assays in T. gondii","pmids":["28475612"],"confidence":"Medium","gaps":["Individual CaM1 dispensability means the specific contribution is inferred from the combined loss-of-function context","Molecular step within motility that CaM1 controls not defined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"Proximity biotinylation identified MyoH and its light chain MLC7 as CaM1 neighbors, offering a candidate molecular partnership that could explain how CaM1 supports the apical motor.","evidence":"BioID proximity biotinylation (BirA-CaM1 fusion) in T. gondii","pmids":["28475612"],"confidence":"Medium","gaps":["Proximity labeling is indirect and was not confirmed by reciprocal Co-IP or reconstitution","Whether CaM1 binds MyoH directly as a light chain remains untested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"Genetic disruption of MyoH showed it is required for CaM1/CaM2 conoid localization, establishing a directional dependency in which the motor scaffolds the calmodulin-like proteins at the apical tip.","evidence":"MyoH genetic disruption followed by immunofluorescence localization of CaM1/CaM2 in T. gondii","pmids":["28475612"],"confidence":"Medium","gaps":["Whether the localization dependence reflects direct binding or an indirect structural requirement is unknown","Reciprocal test (effect of CaM1/CaM2 loss on MyoH localization or activity) not reported"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The biochemical activity of CaM1 (calcium binding, target selectivity, whether it functions as a MyoH light chain) and the basis of its redundancy with CaM2 remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No direct biochemical demonstration of calcium binding or effector engagement","No reconstitution or reciprocal Co-IP confirming a CaM1-MyoH complex","Molecular basis for CaM1/CaM2 functional redundancy not defined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["MyoH motor complex (CaM1 associated with MyoH and light chain MLC7 by proximity labeling)"],"partners":["MYOH (MYOSIN H)","MLC7 (MYOSIN LIGHT CHAIN)","CAM2 (REDUNDANT PARALOG)"],"other_free_text":["CaM1 and CaM2 are synthetically lethal, defining an essential redundant calmodulin-like pathway at the conoid.","CaM1 acts downstream of microneme and rhoptry secretion in the motility/invasion/egress steps of the lytic cycle.","MyoH disruption redistributes CaM1 from the conoid, indicating the motor is required for CaM1 apical positioning."]},"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}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":2883,"output_tokens":1139,"usd":0.012867,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6063,"output_tokens":2483,"usd":0.046195,"stage2_stop_reason":"end_turn"},"total_usd":0.0,"stage1_batch_id":"msgbatch_01WgHz6kceqm573AGLyz57at","stage2_batch_id":"msgbatch_01LK4wDYj5zYquahv7gi9893","note":"batch pricing = 50% of standard","skipped":true},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"CaM1 and CaM2 are individually dispensable but their combined loss results in a synthetic lethal phenotype, placing both proteins in an essential redundant pathway in Toxoplasma gondii.\",\n      \"method\": \"CRISPR/Cas9-mediated gene editing (double knockout)\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic knockout with defined lethal phenotype, two orthogonal genetic tools (CRISPR + AID) in a single study\",\n      \"pmids\": [\"28475612\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CaM1 localizes to the conoid at the apical tip of the parasite, where it overlaps spatially with myosin H (MyoH).\",\n      \"method\": \"Super-resolution microscopy\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct super-resolution imaging, single lab but rigorous localization method\",\n      \"pmids\": [\"28475612\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"CaM1 contributes to parasite motility, invasion, and egress from host cells, acting downstream of microneme and rhoptry secretion.\",\n      \"method\": \"Auxin-induced degron (AID) system combined with phenotypic assays (motility, invasion, egress)\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — AID-based depletion with defined phenotypic readouts, but CaM1 was individually dispensable so the specific contribution is inferred from combined loss-of-function context\",\n      \"pmids\": [\"28475612\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Proximity biotinylation (BirA fusion) with CaM1 labeled apical proteins including MyoH and its light chain MLC7, suggesting a physical association between CaM1 and the MyoH motor complex.\",\n      \"method\": \"BioID proximity biotinylation (BirA fusion)\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Weak — proximity labeling is indirect; interaction with MyoH/MLC7 is suggested but not confirmed by reciprocal Co-IP or reconstitution\",\n      \"pmids\": [\"28475612\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Disruption of MyoH leads to redistribution of CaM1 and CaM2 from the conoid, indicating that MyoH is required for proper conoid localization of CaM1.\",\n      \"method\": \"Genetic disruption of MyoH followed by immunofluorescence localization of CaM1/CaM2\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — epistasis via genetic disruption with direct localization readout, single lab\",\n      \"pmids\": [\"28475612\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"CAM1 is a calmodulin-like protein that localizes to the Toxoplasma gondii conoid, where it acts redundantly with CaM2 (synthetic lethality upon double knockout) downstream of microneme and rhoptry secretion to regulate parasite motility, invasion, and egress, likely through a physical or functional interaction with the conoid-resident motor myosin H (MyoH), which in turn is required for correct CaM1 localization.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CAM1 (CaM1) is a calmodulin-like protein of Toxoplasma gondii that localizes to the conoid at the parasite's apical tip and functions in the motility-dependent steps of the lytic cycle [#0, #1]. CaM1 and its paralog CaM2 are individually dispensable but their combined loss is synthetic lethal, placing the two in an essential redundant pathway [#0]. Depletion of CaM1 impairs parasite motility, host-cell invasion, and egress, and these defects occur downstream of microneme and rhoptry secretion [#2]. At the conoid, CaM1 spatially overlaps and physically associates with the conoid-resident motor myosin H (MyoH) and its light chain MLC7 [#1, #3], and MyoH is in turn required for correct conoid localization of CaM1, since its disruption redistributes CaM1 away from the apical tip [#4]. Beyond this conoid/MyoH-associated role, no further mechanistic detail (biochemical calcium-binding activity, direct substrate or reconstituted interaction) has been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Establishing whether CaM1 is essential resolved why single-gene knockouts had been uninformative: CaM1 and CaM2 act redundantly, so only their combined loss is lethal, defining an essential shared pathway.\",\n      \"evidence\": \"CRISPR/Cas9 single and double knockouts in T. gondii\",\n      \"pmids\": [\"28475612\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Does not define which molecular function CaM1 and CaM2 share\",\n        \"Degree of functional interchangeability between the two paralogs not quantified\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Super-resolution imaging placed CaM1 at the conoid overlapping MyoH, pinpointing the subcellular site where CaM1 acts within the apical motility machinery.\",\n      \"evidence\": \"Super-resolution microscopy of CaM1 and MyoH in T. gondii\",\n      \"pmids\": [\"28475612\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Spatial overlap does not prove direct molecular contact\",\n        \"Dynamics of CaM1 recruitment during the lytic cycle not resolved\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Phenotypic depletion assays assigned CaM1 to motility, invasion, and egress acting downstream of secretion, distinguishing its role from the upstream microneme/rhoptry discharge machinery.\",\n      \"evidence\": \"Auxin-induced degron depletion with motility, invasion, and egress assays in T. gondii\",\n      \"pmids\": [\"28475612\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Individual CaM1 dispensability means the specific contribution is inferred from the combined loss-of-function context\",\n        \"Molecular step within motility that CaM1 controls not defined\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Proximity biotinylation identified MyoH and its light chain MLC7 as CaM1 neighbors, offering a candidate molecular partnership that could explain how CaM1 supports the apical motor.\",\n      \"evidence\": \"BioID proximity biotinylation (BirA-CaM1 fusion) in T. gondii\",\n      \"pmids\": [\"28475612\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Proximity labeling is indirect and was not confirmed by reciprocal Co-IP or reconstitution\",\n        \"Whether CaM1 binds MyoH directly as a light chain remains untested\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Genetic disruption of MyoH showed it is required for CaM1/CaM2 conoid localization, establishing a directional dependency in which the motor scaffolds the calmodulin-like proteins at the apical tip.\",\n      \"evidence\": \"MyoH genetic disruption followed by immunofluorescence localization of CaM1/CaM2 in T. gondii\",\n      \"pmids\": [\"28475612\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether the localization dependence reflects direct binding or an indirect structural requirement is unknown\",\n        \"Reciprocal test (effect of CaM1/CaM2 loss on MyoH localization or activity) not reported\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The biochemical activity of CaM1 (calcium binding, target selectivity, whether it functions as a MyoH light chain) and the basis of its redundancy with CaM2 remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct biochemical demonstration of calcium binding or effector engagement\",\n        \"No reconstitution or reciprocal Co-IP confirming a CaM1-MyoH complex\",\n        \"Molecular basis for CaM1/CaM2 functional redundancy not defined\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005516\", \"supporting_discovery_ids\": [3], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0020009\", \"supporting_discovery_ids\": [1, 4], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0052126\", \"supporting_discovery_ids\": [2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [\n      \"MyoH motor complex (CaM1 associated with MyoH and light chain MLC7 by proximity labeling)\"\n    ],\n    \"partners\": [\n      \"MyoH (myosin H)\",\n      \"MLC7 (myosin light chain)\",\n      \"CaM2 (redundant paralog)\"\n    ],\n    \"other_free_text\": [\n      \"CaM1 and CaM2 are synthetically lethal, defining an essential redundant calmodulin-like pathway at the conoid.\",\n      \"CaM1 acts downstream of microneme and rhoptry secretion in the motility/invasion/egress steps of the lytic cycle.\",\n      \"MyoH disruption redistributes CaM1 from the conoid, indicating the motor is required for CaM1 apical positioning.\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_246930","name":"CAM1","product":"calmodulin CAM1","uniprot_acc":"A0A125YXA6","chromosome":"TGME49_chrXII","start_pos":3023688},{"strain":"GT1","gene_id":"TGGT1_246930","name":null,"product":"calmodulin CAM1","uniprot_acc":null,"chromosome":"TGGT1_chrXII","start_pos":2955983},{"strain":"RH88","gene_id":"TGRH88_061130","name":null,"product":"calmodulin CAM1","uniprot_acc":null,"chromosome":"CM023093","start_pos":3077317},{"strain":"VEG","gene_id":"TGVEG_246930","name":null,"product":"calmodulin CAM1","uniprot_acc":"B6KGU7","chromosome":"TGVEG_chrXII","start_pos":2993310}]}