{"gene":"TG_232340","gene_symbol":"PPM2A","run_date":"2026-09-08T12:58:24","timeline":{"discoveries":[{"year":2024,"finding":"PPM2A is distributed throughout the whole tachyzoite of T. gondii (whole-cell localization), as determined by insertion of a 10HA tag at the C-terminus in the RHΔku80 strain.","method":"Endogenous C-terminal 10HA epitope tagging and immunofluorescence localization in RHΔku80 strain","journal":"Molecular and biochemical parasitology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct localization experiment with epitope tag, single lab, single method","pmids":["39461506"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"RHΔku80"}]},{"year":2024,"finding":"PPM2A was identified as an interacting protein of Toxoplasma Calmodulin via proximity-based BioID proteomics, placing PPM2A in the calmodulin interaction network.","method":"BioID proximity-based protein interaction assay (reported from a prior study, referenced in this paper)","journal":"Molecular and biochemical parasitology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single BioID screen cited from a previous study, no reciprocal validation reported","pmids":["39461506"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"finding":"Knockout of PPM2A alone (Δppm2a), PPM2B alone (Δppm2b), or both (ΔΔ) did not result in intracellular replication defect and did not reduce pathogenicity in mice compared to the parental RHΔhxgprt strain; however, plaque sizes of all knockout strains were smaller than the control, indicating PPM2A contributes to parasite fitness (plaque formation) but is dispensable for intracellular replication.","method":"CRISPR-Cas9 knockout generation, intracellular replication assay, plaque assay, and mouse virulence experiments","journal":"Molecular and biochemical parasitology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic KO with multiple phenotypic readouts (replication, plaque, mouse virulence) in a single lab","pmids":["39461506"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"RHΔhxgprt"}]}],"current_model":"PPM2A is a PPM-family serine/threonine phosphatase distributed throughout the T. gondii tachyzoite that interacts with Calmodulin and contributes to parasite fitness (plaque size) but is dispensable for intracellular replication and acute virulence in mice."},"narrative":{"mechanistic_narrative":"PPM2A is a PPM-family serine/threonine phosphatase of Toxoplasma gondii that contributes to tachyzoite fitness while being dispensable for the core intracellular replication cycle [PMID:39461506]. Endogenous C-terminal tagging localizes the protein throughout the whole tachyzoite rather than to a discrete compartment [PMID:39461506], and it falls within the parasite Calmodulin interaction network [PMID:39461506]. Genetic ablation of PPM2A, of the related PPM2B, or of both together leaves intracellular replication and acute virulence in mice intact, yet reduces plaque size, indicating a fitness contribution independent of the replication defect [PMID:39461506]. Beyond these observations, the enzyme's substrates, catalytic regulation, and the functional consequence of the Calmodulin association have not been characterized in the available corpus.","teleology":[{"year":2024,"claim":"To place PPM2A in a cellular context, its subcellular distribution was resolved, establishing that the phosphatase is not restricted to a single organelle but spread throughout the tachyzoite.","evidence":"Endogenous C-terminal 10HA tagging and immunofluorescence in RHΔku80","pmids":["39461506"],"confidence":"Medium","gaps":["Whole-cell signal does not resolve whether PPM2A concentrates at any structure under specific cell-cycle or stress conditions","Single tag, single method, no orthogonal localization"],"attribution":[{"species":"Toxoplasma gondii","strain":"RHΔku80"}]},{"year":2024,"claim":"To identify functional partners, PPM2A was recovered in a Calmodulin proximity interactome, linking the phosphatase to calcium/calmodulin signaling machinery.","evidence":"BioID proximity proteomics for Toxoplasma Calmodulin (cited from prior study)","pmids":["39461506"],"confidence":"Low","gaps":["Single BioID screen with no reciprocal validation","Proximity labeling does not establish a direct or functionally relevant interaction","No demonstration that Calmodulin regulates PPM2A activity"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"claim":"To test whether PPM2A is required for the lytic cycle, single and double knockouts of PPM2A and the paralog PPM2B were generated and phenotyped, showing the phosphatase is dispensable for replication and acute virulence but contributes to overall fitness.","evidence":"CRISPR-Cas9 knockout with replication, plaque, and mouse virulence assays in RHΔhxgprt","pmids":["39461506"],"confidence":"Medium","gaps":["The step in the lytic cycle responsible for the plaque-size defect is not identified","No molecular explanation (substrate or pathway) for the fitness contribution","Functional redundancy between PPM2A and PPM2B not resolved by the double knockout phenotype"],"attribution":[{"species":"Toxoplasma gondii","strain":"RHΔhxgprt"}]},{"year":null,"claim":"The catalytic substrates of PPM2A, the mechanistic basis of its Calmodulin association, and the cellular process underlying its fitness contribution remain unknown.","evidence":"","pmids":[],"confidence":"Low","gaps":["No phosphatase substrate identified","No evidence that Calmodulin binding modulates catalytic activity","No structural or biochemical characterization of the enzyme"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["CALMODULIN (BIOID PROXIMITY INTERACTOR)","PPM2B (PARALOG; CO-DELETED IN DOUBLE KNOCKOUT)"],"other_free_text":["PPM-family serine/threonine phosphatase of Toxoplasma gondii [#2].","Dispensable for intracellular replication and acute virulence in mice; loss reduces plaque size, indicating a fitness contribution [#2]."]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"39461506","id":"PMC_39461506","title":"Characterization of two phosphatase 2 C domain-containing proteins PPM2A and PPM2B in Toxoplasma gondii.","date":"2024","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/39461506","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":2974,"output_tokens":822,"usd":0.010626,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5605,"output_tokens":1650,"usd":0.034638,"stage2_stop_reason":"end_turn"},"total_usd":0.045264,"stage1_batch_id":"msgbatch_01TEPNZ4MCzJ7xtsNwosiDRk","stage2_batch_id":"msgbatch_01FQShM7n1sfCr4pWTDShmki","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2024,\n      \"finding\": \"PPM2A is distributed throughout the whole tachyzoite of T. gondii (whole-cell localization), as determined by insertion of a 10HA tag at the C-terminus in the RHΔku80 strain.\",\n      \"method\": \"Endogenous C-terminal 10HA epitope tagging and immunofluorescence localization in RHΔku80 strain\",\n      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct localization experiment with epitope tag, single lab, single method\",\n      \"pmids\": [\"39461506\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RHΔku80\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PPM2A was identified as an interacting protein of Toxoplasma Calmodulin via proximity-based BioID proteomics, placing PPM2A in the calmodulin interaction network.\",\n      \"method\": \"BioID proximity-based protein interaction assay (reported from a prior study, referenced in this paper)\",\n      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single BioID screen cited from a previous study, no reciprocal validation reported\",\n      \"pmids\": [\"39461506\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Knockout of PPM2A alone (Δppm2a), PPM2B alone (Δppm2b), or both (ΔΔ) did not result in intracellular replication defect and did not reduce pathogenicity in mice compared to the parental RHΔhxgprt strain; however, plaque sizes of all knockout strains were smaller than the control, indicating PPM2A contributes to parasite fitness (plaque formation) but is dispensable for intracellular replication.\",\n      \"method\": \"CRISPR-Cas9 knockout generation, intracellular replication assay, plaque assay, and mouse virulence experiments\",\n      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic KO with multiple phenotypic readouts (replication, plaque, mouse virulence) in a single lab\",\n      \"pmids\": [\"39461506\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RHΔhxgprt\"}]\n    }\n  ],\n  \"current_model\": \"PPM2A is a PPM-family serine/threonine phosphatase distributed throughout the T. gondii tachyzoite that interacts with Calmodulin and contributes to parasite fitness (plaque size) but is dispensable for intracellular replication and acute virulence in mice.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PPM2A is a PPM-family serine/threonine phosphatase of Toxoplasma gondii that contributes to tachyzoite fitness while being dispensable for the core intracellular replication cycle [#2]. Endogenous C-terminal tagging localizes the protein throughout the whole tachyzoite rather than to a discrete compartment [#0], and it falls within the parasite Calmodulin interaction network [#1]. Genetic ablation of PPM2A, of the related PPM2B, or of both together leaves intracellular replication and acute virulence in mice intact, yet reduces plaque size, indicating a fitness contribution independent of the replication defect [#2]. Beyond these observations, the enzyme's substrates, catalytic regulation, and the functional consequence of the Calmodulin association have not been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2024,\n      \"claim\": \"To place PPM2A in a cellular context, its subcellular distribution was resolved, establishing that the phosphatase is not restricted to a single organelle but spread throughout the tachyzoite.\",\n      \"evidence\": \"Endogenous C-terminal 10HA tagging and immunofluorescence in RH\\u0394ku80\",\n      \"pmids\": [\"39461506\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whole-cell signal does not resolve whether PPM2A concentrates at any structure under specific cell-cycle or stress conditions\", \"Single tag, single method, no orthogonal localization\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\\u0394ku80\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"To identify functional partners, PPM2A was recovered in a Calmodulin proximity interactome, linking the phosphatase to calcium/calmodulin signaling machinery.\",\n      \"evidence\": \"BioID proximity proteomics for Toxoplasma Calmodulin (cited from prior study)\",\n      \"pmids\": [\"39461506\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single BioID screen with no reciprocal validation\", \"Proximity labeling does not establish a direct or functionally relevant interaction\", \"No demonstration that Calmodulin regulates PPM2A activity\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"To test whether PPM2A is required for the lytic cycle, single and double knockouts of PPM2A and the paralog PPM2B were generated and phenotyped, showing the phosphatase is dispensable for replication and acute virulence but contributes to overall fitness.\",\n      \"evidence\": \"CRISPR-Cas9 knockout with replication, plaque, and mouse virulence assays in RH\\u0394hxgprt\",\n      \"pmids\": [\"39461506\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The step in the lytic cycle responsible for the plaque-size defect is not identified\", \"No molecular explanation (substrate or pathway) for the fitness contribution\", \"Functional redundancy between PPM2A and PPM2B not resolved by the double knockout phenotype\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\\u0394hxgprt\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The catalytic substrates of PPM2A, the mechanistic basis of its Calmodulin association, and the cellular process underlying its fitness contribution remain unknown.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No phosphatase substrate identified\", \"No evidence that Calmodulin binding modulates catalytic activity\", \"No structural or biochemical characterization of the enzyme\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0005737\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\\u0394ku80\"}]}\n    ],\n    \"pathway\": [],\n    \"complexes\": [],\n    \"partners\": [\"Calmodulin (BioID proximity interactor)\", \"PPM2B (paralog; co-deleted in double knockout)\"],\n    \"other_free_text\": [\n      \"PPM-family serine/threonine phosphatase of Toxoplasma gondii [#2].\",\n      \"Dispensable for intracellular replication and acute virulence in mice; loss reduces plaque size, indicating a fitness contribution [#2].\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_232340","name":"PPM2A","product":"protein phosphatase PPM2A","uniprot_acc":"S8F5Y7","chromosome":"TGME49_chrVIII","start_pos":2018128},{"strain":"GT1","gene_id":"TGGT1_232340","name":null,"product":"protein phosphatase 2C domain-containing protein","uniprot_acc":null,"chromosome":"TGGT1_chrVIII","start_pos":2014510},{"strain":"RH88","gene_id":"TGRH88_076460","name":null,"product":"protein phosphatase 2C domain-containing protein","uniprot_acc":null,"chromosome":"CM023089","start_pos":7124798},{"strain":"VEG","gene_id":"TGVEG_232340","name":null,"product":"protein phosphatase 2C domain-containing protein","uniprot_acc":"B9Q4R2","chromosome":"TGVEG_chrVIII","start_pos":2025586}]}