{"gene":"TG_281980","gene_symbol":"CDS1","run_date":"2026-09-08T14:08:30","timeline":{"discoveries":[{"year":2017,"finding":"TgCDS1 is a eukaryotic-type CDP-diacylglycerol synthase that localizes to the endoplasmic reticulum of T. gondii, where it produces a CDP-DAG pool used preferentially for phosphatidylinositol synthesis in the Golgi bodies.","method":"Subcellular localization by direct imaging, conditional knockdown with lipidomic analysis revealing specific decline in phosphatidylinositol levels","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional knockdown with defined metabolic phenotype (lipidomic readout) combined with direct localization; single lab but multiple orthogonal methods","pmids":["28314772"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"Conditional knockdown of TgCDS1 severely attenuates parasite growth and results in nearly complete loss of virulence in a mouse model, establishing TgCDS1 as essential for asexual replication.","method":"Conditional knockdown (loss-of-function) with parasite growth assay and mouse virulence model","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional knockdown with in vivo virulence readout and growth phenotype, single lab but multiple readouts","pmids":["28314772"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"TgCDS1 (ER-localized) and TgCDS2 (apicoplast-localized) cooperate in a 'division of labor' for lipid biogenesis: TgCDS1-derived CDP-DAG feeds phosphatidylinositol synthesis, while TgCDS2-derived CDP-DAG feeds phosphatidylglycerol synthesis in mitochondria; residual growth of the TgCDS1 mutant was abolished by consecutive deletion of TgCDS2, demonstrating functional complementarity.","method":"Genetic epistasis via consecutive deletion of TgCDS2 in TgCDS1 conditional knockdown background, combined with lipidomic analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis (double mutant) combined with lipidomic profiling establishing pathway positions, single lab but multiple orthogonal methods","pmids":["28314772"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"TgCDS1 is a eukaryotic-type CDP-diacylglycerol synthase residing in the endoplasmic reticulum that is essential for T. gondii asexual replication and virulence; it produces a CDP-DAG pool used for phosphatidylinositol synthesis in the Golgi bodies, cooperating with the apicoplast-localized prokaryotic-type TgCDS2 (which supplies CDP-DAG for mitochondrial phosphatidylglycerol synthesis) in a division-of-labor model of glycerophospholipid biogenesis."},"narrative":{"mechanistic_narrative":"TgCDS1 is a eukaryotic-type CDP-diacylglycerol synthase that resides in the endoplasmic reticulum of Toxoplasma gondii and drives glycerophospholipid biogenesis by generating a CDP-DAG pool used preferentially for phosphatidylinositol synthesis in the Golgi bodies [PMID:28314772]. It operates in a division-of-labor arrangement with the apicoplast-localized prokaryotic-type TgCDS2: TgCDS1-derived CDP-DAG feeds phosphatidylinositol synthesis while TgCDS2-derived CDP-DAG feeds mitochondrial phosphatidylglycerol synthesis, and the residual growth of the TgCDS1 mutant is abolished only by additional deletion of TgCDS2, establishing their functional complementarity [PMID:28314772]. TgCDS1 is essential for asexual replication, as its conditional knockdown severely attenuates parasite growth and nearly eliminates virulence in mice [PMID:28314772]. Beyond these findings, no further mechanistic detail on TgCDS1 catalysis, regulation, or structure has been characterized in the available corpus.","teleology":[{"year":2017,"claim":"It was unknown which enzyme generates the CDP-DAG feeding phosphatidylinositol synthesis in T. gondii; localizing TgCDS1 to the ER and linking its knockdown to a specific drop in phosphatidylinositol established it as a eukaryotic-type CDP-DAG synthase dedicated to PI biogenesis.","evidence":"Direct imaging for localization plus conditional knockdown with lipidomic profiling","pmids":["28314772"],"confidence":"High","gaps":["No direct enzymatic reconstitution of CDP-DAG synthase activity","No structural model or catalytic residue mapping","Mechanism directing CDP-DAG preferentially toward Golgi PI synthesis unresolved"],"attribution":[]},{"year":2017,"claim":"Whether TgCDS1 is required for parasite fitness was unknown; conditional knockdown showing severe growth attenuation and near-complete loss of virulence established it as essential for asexual replication.","evidence":"Conditional knockdown with growth assay and mouse virulence model","pmids":["28314772"],"confidence":"High","gaps":["Whether attenuation is directly attributable to phosphatidylinositol depletion versus broader lipid imbalance not fully dissected","Contribution to stages beyond asexual replication untested"],"attribution":[]},{"year":2017,"claim":"It was unclear how the ER and apicoplast CDP-DAG synthases partition their roles; genetic epistasis showed TgCDS1 and TgCDS2 act in a division of labor, with double deletion abolishing residual growth.","evidence":"Consecutive deletion of TgCDS2 in a TgCDS1 knockdown background with lipidomic analysis","pmids":["28314772"],"confidence":"High","gaps":["Extent of functional overlap/redundancy between the two synthases not quantified","Regulation coordinating the two pools unknown"],"attribution":[]},{"year":null,"claim":"The catalytic mechanism, structural basis, and regulation of TgCDS1, and the determinants routing its CDP-DAG product to Golgi phosphatidylinositol synthesis, remain unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No in vitro reconstitution of enzyme activity","No structural data","Trafficking of CDP-DAG from ER to Golgi uncharacterized"],"attribution":[]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["TGCDS2 (FUNCTIONALLY COMPLEMENTARY APICOPLAST-LOCALIZED CDP-DAG SYNTHASE)"],"other_free_text":["Essential for T. gondii asexual replication and virulence [#1]","Division-of-labor model: TgCDS1 (ER) supplies CDP-DAG for phosphatidylinositol; TgCDS2 (apicoplast) supplies CDP-DAG for mitochondrial phosphatidylglycerol [#2]"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"28314772","id":"PMC_28314772","title":"Two phylogenetically and compartmentally distinct CDP-diacylglycerol synthases cooperate for lipid biogenesis in Toxoplasma gondii.","date":"2017","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/28314772","citation_count":27,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":3051,"output_tokens":928,"usd":0.011536,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5778,"output_tokens":1829,"usd":0.037308,"stage2_stop_reason":"end_turn"},"total_usd":0.048844,"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\": 2017,\n      \"finding\": \"TgCDS1 is a eukaryotic-type CDP-diacylglycerol synthase that localizes to the endoplasmic reticulum of T. gondii, where it produces a CDP-DAG pool used preferentially for phosphatidylinositol synthesis in the Golgi bodies.\",\n      \"method\": \"Subcellular localization by direct imaging, conditional knockdown with lipidomic analysis revealing specific decline in phosphatidylinositol levels\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional knockdown with defined metabolic phenotype (lipidomic readout) combined with direct localization; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"28314772\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Conditional knockdown of TgCDS1 severely attenuates parasite growth and results in nearly complete loss of virulence in a mouse model, establishing TgCDS1 as essential for asexual replication.\",\n      \"method\": \"Conditional knockdown (loss-of-function) with parasite growth assay and mouse virulence model\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional knockdown with in vivo virulence readout and growth phenotype, single lab but multiple readouts\",\n      \"pmids\": [\"28314772\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TgCDS1 (ER-localized) and TgCDS2 (apicoplast-localized) cooperate in a 'division of labor' for lipid biogenesis: TgCDS1-derived CDP-DAG feeds phosphatidylinositol synthesis, while TgCDS2-derived CDP-DAG feeds phosphatidylglycerol synthesis in mitochondria; residual growth of the TgCDS1 mutant was abolished by consecutive deletion of TgCDS2, demonstrating functional complementarity.\",\n      \"method\": \"Genetic epistasis via consecutive deletion of TgCDS2 in TgCDS1 conditional knockdown background, combined with lipidomic analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis (double mutant) combined with lipidomic profiling establishing pathway positions, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"28314772\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"TgCDS1 is a eukaryotic-type CDP-diacylglycerol synthase residing in the endoplasmic reticulum that is essential for T. gondii asexual replication and virulence; it produces a CDP-DAG pool used for phosphatidylinositol synthesis in the Golgi bodies, cooperating with the apicoplast-localized prokaryotic-type TgCDS2 (which supplies CDP-DAG for mitochondrial phosphatidylglycerol synthesis) in a division-of-labor model of glycerophospholipid biogenesis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TgCDS1 is a eukaryotic-type CDP-diacylglycerol synthase that resides in the endoplasmic reticulum of Toxoplasma gondii and drives glycerophospholipid biogenesis by generating a CDP-DAG pool used preferentially for phosphatidylinositol synthesis in the Golgi bodies [#0]. It operates in a division-of-labor arrangement with the apicoplast-localized prokaryotic-type TgCDS2: TgCDS1-derived CDP-DAG feeds phosphatidylinositol synthesis while TgCDS2-derived CDP-DAG feeds mitochondrial phosphatidylglycerol synthesis, and the residual growth of the TgCDS1 mutant is abolished only by additional deletion of TgCDS2, establishing their functional complementarity [#2]. TgCDS1 is essential for asexual replication, as its conditional knockdown severely attenuates parasite growth and nearly eliminates virulence in mice [#1]. Beyond these findings, no further mechanistic detail on TgCDS1 catalysis, regulation, or structure has been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"It was unknown which enzyme generates the CDP-DAG feeding phosphatidylinositol synthesis in T. gondii; localizing TgCDS1 to the ER and linking its knockdown to a specific drop in phosphatidylinositol established it as a eukaryotic-type CDP-DAG synthase dedicated to PI biogenesis.\",\n      \"evidence\": \"Direct imaging for localization plus conditional knockdown with lipidomic profiling\",\n      \"pmids\": [\"28314772\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No direct enzymatic reconstitution of CDP-DAG synthase activity\", \"No structural model or catalytic residue mapping\", \"Mechanism directing CDP-DAG preferentially toward Golgi PI synthesis unresolved\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Whether TgCDS1 is required for parasite fitness was unknown; conditional knockdown showing severe growth attenuation and near-complete loss of virulence established it as essential for asexual replication.\",\n      \"evidence\": \"Conditional knockdown with growth assay and mouse virulence model\",\n      \"pmids\": [\"28314772\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether attenuation is directly attributable to phosphatidylinositol depletion versus broader lipid imbalance not fully dissected\", \"Contribution to stages beyond asexual replication untested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"It was unclear how the ER and apicoplast CDP-DAG synthases partition their roles; genetic epistasis showed TgCDS1 and TgCDS2 act in a division of labor, with double deletion abolishing residual growth.\",\n      \"evidence\": \"Consecutive deletion of TgCDS2 in a TgCDS1 knockdown background with lipidomic analysis\",\n      \"pmids\": [\"28314772\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Extent of functional overlap/redundancy between the two synthases not quantified\", \"Regulation coordinating the two pools unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The catalytic mechanism, structural basis, and regulation of TgCDS1, and the determinants routing its CDP-DAG product to Golgi phosphatidylinositol synthesis, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No in vitro reconstitution of enzyme activity\", \"No structural data\", \"Trafficking of CDP-DAG from ER to Golgi uncharacterized\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004605\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0006661\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0046474\", \"supporting_discovery_ids\": [2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"TgCDS2 (functionally complementary apicoplast-localized CDP-DAG synthase)\"],\n    \"other_free_text\": [\n      \"Essential for T. gondii asexual replication and virulence [#1]\",\n      \"Division-of-labor model: TgCDS1 (ER) supplies CDP-DAG for phosphatidylinositol; TgCDS2 (apicoplast) supplies CDP-DAG for mitochondrial phosphatidylglycerol [#2]\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_281980","name":"CDS1","product":"phosphatidate cytidylyltransferase","uniprot_acc":"S8F6P0","chromosome":"TGME49_chrVIIa","start_pos":4301759},{"strain":"GT1","gene_id":"TGGT1_281980","name":null,"product":"phosphatidate cytidylyltransferase","uniprot_acc":null,"chromosome":"TGGT1_chrVIIa","start_pos":4205847},{"strain":"RH88","gene_id":"TGRH88_037980","name":null,"product":"phosphatidate cytidylyltransferase","uniprot_acc":null,"chromosome":"CM023088","start_pos":4413604},{"strain":"VEG","gene_id":"TGVEG_281980","name":null,"product":"phosphatidate cytidylyltransferase","uniprot_acc":"B9QPH3","chromosome":"TGVEG_chrVIIa","start_pos":4396875}]}