{"gene":"TG_265790","gene_symbol":"CLAMP","run_date":"2026-09-08T14:08:29","timeline":{"discoveries":[{"year":2023,"finding":"CLAMP is a microneme protein that forms a distinct complex with two other microneme proteins, SPATR and a previously uncharacterized protein named CLIP (CLAMP-linked invasion protein), and this complex is essential for rhoptry discharge following host cell contact in Toxoplasma gondii.","method":"Conditional knockdown, Co-immunoprecipitation/complex identification, rhoptry discharge assay, microneme secretion assay, host cell adhesion assay","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal complex identification with multiple orthogonal functional assays (knockdown of each component, secretion assays, adhesion assays) establishing pathway position; single lab but multiple rigorous methods","pmids":["37886905"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"finding":"CLAMP deficiency does not impair parasite adhesion to host cells or microneme protein secretion, but specifically abrogates rhoptry discharge, placing CLAMP function downstream of microneme secretion and host cell binding but upstream of rhoptry exocytosis.","method":"Conditional knockdown with specific functional assays for adhesion, microneme secretion, and rhoptry discharge","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic loss-of-function with multiple orthogonal phenotypic readouts distinguishing adhesion, microneme secretion, and rhoptry discharge steps; single lab","pmids":["37886905"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"finding":"Conditional depletion of CLAMP abolishes the transient host cell plasma membrane perforation that normally precedes Toxoplasma invasion, consistent with CLAMP acting as a signaling protein required to trigger rhoptry secretion whose contents mediate host membrane disruption.","method":"High-speed multi-wavelength fluorescence imaging assay for host cell perforation combined with conditional knockdown of CLAMP","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — novel fluorescence-based perforation assay with clean conditional knockdown, but preprint/single study with no independent replication","pmids":["39605356"],"is_preprint":true,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"CLAMP is a Toxoplasma gondii microneme protein that forms an essential trimeric complex with SPATR and CLIP; this complex acts downstream of host cell adhesion and microneme secretion but is specifically required to trigger rhoptry discharge upon host cell contact, and loss of CLAMP prevents the transient host cell plasma membrane perforation through which rhoptry effector proteins are delivered during invasion."},"narrative":{"mechanistic_narrative":"CLAMP is a Toxoplasma gondii microneme protein that functions as an essential trigger for rhoptry discharge during host cell invasion [PMID:37886905]. It forms a distinct trimeric complex with two other microneme proteins, SPATR and the previously uncharacterized CLIP (CLAMP-linked invasion protein) [PMID:37886905]. Genetic dissection places CLAMP downstream of host cell adhesion and microneme secretion—both of which proceed normally in its absence—but strictly upstream of rhoptry exocytosis, which is specifically abrogated upon CLAMP loss [PMID:37886905]. Consistent with a role in triggering rhoptry secretion, CLAMP depletion abolishes the transient host cell plasma membrane perforation that normally precedes invasion and through which rhoptry contents are delivered [PMID:39605356]. Beyond these functional placements, the molecular mechanism by which the CLAMP complex senses host contact and signals rhoptry discharge has not been characterized in the available corpus.","teleology":[{"year":2023,"claim":"Establishing what CLAMP does molecularly required identifying its interaction partners and its position in the invasion cascade; this work defined CLAMP as part of a discrete microneme complex essential for rhoptry discharge.","evidence":"Conditional knockdown with reciprocal co-immunoprecipitation and rhoptry discharge, microneme secretion, and adhesion assays in Toxoplasma gondii","pmids":["37886905"],"confidence":"High","gaps":["The stoichiometry and structural architecture of the CLAMP-SPATR-CLIP complex are not resolved","How the complex is assembled and trafficked to the microneme is unknown"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"claim":"To localize CLAMP function within the ordered steps of invasion, phenotypic readouts distinguished adhesion, microneme secretion, and rhoptry discharge, showing CLAMP acts specifically at the rhoptry discharge step.","evidence":"Conditional knockdown with step-specific functional assays in Toxoplasma gondii","pmids":["37886905"],"confidence":"High","gaps":["The molecular signal that links host cell contact to CLAMP-dependent rhoptry triggering is unidentified","Whether CLAMP directly senses the host cell or acts through an intermediate is unknown"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"claim":"Connecting CLAMP function to the physical event of host membrane breach, imaging showed CLAMP is required for the transient plasma membrane perforation preceding invasion, tying rhoptry triggering to effector delivery.","evidence":"High-speed multi-wavelength fluorescence perforation assay with conditional CLAMP knockdown in Toxoplasma gondii (preprint)","pmids":["39605356"],"confidence":"Medium","gaps":["Preprint/single study without independent replication","Whether the perforation defect is a direct consequence of absent rhoptry discharge or a separate CLAMP function is not distinguished","The rhoptry effectors that mediate perforation downstream of CLAMP are not identified"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The molecular mechanism by which the CLAMP-SPATR-CLIP complex detects host cell contact and transduces that signal to trigger rhoptry exocytosis remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No signaling intermediates linking CLAMP to the rhoptry exocytosis machinery are defined","No structural model of the CLAMP complex exists","The direct biochemical activity of CLAMP is uncharacterized"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["CLAMP-SPATR-CLIP microneme complex"],"partners":["SPATR","CLIP (CLAMP-LINKED INVASION PROTEIN)"],"other_free_text":["CLAMP is a microneme protein required to trigger rhoptry discharge upon host cell contact","CLAMP acts downstream of host cell adhesion and microneme secretion but upstream of rhoptry exocytosis","CLAMP depletion abolishes the transient host cell plasma membrane perforation preceding invasion"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"16889642","id":"PMC_16889642","title":"Ammonia permeability of the aquaglyceroporins from Plasmodium falciparum, Toxoplasma gondii and Trypansoma brucei.","date":"2006","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/16889642","citation_count":67,"is_preprint":false},{"pmid":"37886905","id":"PMC_37886905","title":"A conserved complex of microneme proteins mediates rhoptry discharge in Toxoplasma.","date":"2023","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/37886905","citation_count":21,"is_preprint":false},{"pmid":"39605356","id":"PMC_39605356","title":"Perforation of the host cell plasma membrane during Toxoplasma gondii invasion requires rhoptry exocytosis.","date":"2024","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/39605356","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":3967,"output_tokens":841,"usd":0.012258,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5698,"output_tokens":1947,"usd":0.038582,"stage2_stop_reason":"end_turn"},"total_usd":0.05084,"stage1_batch_id":"msgbatch_015xmQKDRqnTh9anE4m7LiD6","stage2_batch_id":"msgbatch_01JLpkFTVhoQBNgqHCKFrVVU","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2023,\n      \"finding\": \"CLAMP is a microneme protein that forms a distinct complex with two other microneme proteins, SPATR and a previously uncharacterized protein named CLIP (CLAMP-linked invasion protein), and this complex is essential for rhoptry discharge following host cell contact in Toxoplasma gondii.\",\n      \"method\": \"Conditional knockdown, Co-immunoprecipitation/complex identification, rhoptry discharge assay, microneme secretion assay, host cell adhesion assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal complex identification with multiple orthogonal functional assays (knockdown of each component, secretion assays, adhesion assays) establishing pathway position; single lab but multiple rigorous methods\",\n      \"pmids\": [\"37886905\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CLAMP deficiency does not impair parasite adhesion to host cells or microneme protein secretion, but specifically abrogates rhoptry discharge, placing CLAMP function downstream of microneme secretion and host cell binding but upstream of rhoptry exocytosis.\",\n      \"method\": \"Conditional knockdown with specific functional assays for adhesion, microneme secretion, and rhoptry discharge\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic loss-of-function with multiple orthogonal phenotypic readouts distinguishing adhesion, microneme secretion, and rhoptry discharge steps; single lab\",\n      \"pmids\": [\"37886905\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Conditional depletion of CLAMP abolishes the transient host cell plasma membrane perforation that normally precedes Toxoplasma invasion, consistent with CLAMP acting as a signaling protein required to trigger rhoptry secretion whose contents mediate host membrane disruption.\",\n      \"method\": \"High-speed multi-wavelength fluorescence imaging assay for host cell perforation combined with conditional knockdown of CLAMP\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — novel fluorescence-based perforation assay with clean conditional knockdown, but preprint/single study with no independent replication\",\n      \"pmids\": [\"39605356\"],\n      \"is_preprint\": true,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"CLAMP is a Toxoplasma gondii microneme protein that forms an essential trimeric complex with SPATR and CLIP; this complex acts downstream of host cell adhesion and microneme secretion but is specifically required to trigger rhoptry discharge upon host cell contact, and loss of CLAMP prevents the transient host cell plasma membrane perforation through which rhoptry effector proteins are delivered during invasion.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"CLAMP is a Toxoplasma gondii microneme protein that functions as an essential trigger for rhoptry discharge during host cell invasion [#0]. It forms a distinct trimeric complex with two other microneme proteins, SPATR and the previously uncharacterized CLIP (CLAMP-linked invasion protein) [#0]. Genetic dissection places CLAMP downstream of host cell adhesion and microneme secretion—both of which proceed normally in its absence—but strictly upstream of rhoptry exocytosis, which is specifically abrogated upon CLAMP loss [#1]. Consistent with a role in triggering rhoptry secretion, CLAMP depletion abolishes the transient host cell plasma membrane perforation that normally precedes invasion and through which rhoptry contents are delivered [#2]. Beyond these functional placements, the molecular mechanism by which the CLAMP complex senses host contact and signals rhoptry discharge has not been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2023,\n      \"claim\": \"Establishing what CLAMP does molecularly required identifying its interaction partners and its position in the invasion cascade; this work defined CLAMP as part of a discrete microneme complex essential for rhoptry discharge.\",\n      \"evidence\": \"Conditional knockdown with reciprocal co-immunoprecipitation and rhoptry discharge, microneme secretion, and adhesion assays in Toxoplasma gondii\",\n      \"pmids\": [\"37886905\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"The stoichiometry and structural architecture of the CLAMP-SPATR-CLIP complex are not resolved\",\n        \"How the complex is assembled and trafficked to the microneme is unknown\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"To localize CLAMP function within the ordered steps of invasion, phenotypic readouts distinguished adhesion, microneme secretion, and rhoptry discharge, showing CLAMP acts specifically at the rhoptry discharge step.\",\n      \"evidence\": \"Conditional knockdown with step-specific functional assays in Toxoplasma gondii\",\n      \"pmids\": [\"37886905\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"The molecular signal that links host cell contact to CLAMP-dependent rhoptry triggering is unidentified\",\n        \"Whether CLAMP directly senses the host cell or acts through an intermediate is unknown\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Connecting CLAMP function to the physical event of host membrane breach, imaging showed CLAMP is required for the transient plasma membrane perforation preceding invasion, tying rhoptry triggering to effector delivery.\",\n      \"evidence\": \"High-speed multi-wavelength fluorescence perforation assay with conditional CLAMP knockdown in Toxoplasma gondii (preprint)\",\n      \"pmids\": [\"39605356\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Preprint/single study without independent replication\",\n        \"Whether the perforation defect is a direct consequence of absent rhoptry discharge or a separate CLAMP function is not distinguished\",\n        \"The rhoptry effectors that mediate perforation downstream of CLAMP are not identified\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular mechanism by which the CLAMP-SPATR-CLIP complex detects host cell contact and transduces that signal to trigger rhoptry exocytosis remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"No signaling intermediates linking CLAMP to the rhoptry exocytosis machinery are defined\",\n        \"No structural model of the CLAMP complex exists\",\n        \"The direct biochemical activity of CLAMP is uncharacterized\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0020009\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0044409\", \"supporting_discovery_ids\": [0, 1, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [\"CLAMP-SPATR-CLIP microneme complex\"],\n    \"partners\": [\"SPATR\", \"CLIP (CLAMP-linked invasion protein)\"],\n    \"other_free_text\": [\n      \"CLAMP is a microneme protein required to trigger rhoptry discharge upon host cell contact\",\n      \"CLAMP acts downstream of host cell adhesion and microneme secretion but upstream of rhoptry exocytosis\",\n      \"CLAMP depletion abolishes the transient host cell plasma membrane perforation preceding invasion\"\n    ]\n  },\n  \"strain_conflicts\": []\n}\n```","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_265790","name":"CLAMP","product":"claudin-like apicomplexan microneme protein","uniprot_acc":"A0A125YPD4","chromosome":"TGME49_chrIX","start_pos":1448908},{"strain":"GT1","gene_id":"TGGT1_265790","name":null,"product":"hypothetical protein","uniprot_acc":null,"chromosome":"TGGT1_chrIX","start_pos":1272372},{"strain":"RH88","gene_id":"TGRH88_011890","name":null,"product":"unspecified product","uniprot_acc":null,"chromosome":"CM023090","start_pos":1506515},{"strain":"VEG","gene_id":"TGVEG_265790","name":null,"product":"putative multitransmembrane with signal peptide and GMGPP repeat at carboxy-terminus protein","uniprot_acc":"B9Q1C7","chromosome":"TGVEG_chrIX","start_pos":1479204}]}