{"gene":"TG_280400","gene_symbol":"DPY19","run_date":"2026-09-08T14:08:30","timeline":{"discoveries":[{"year":2018,"finding":"Toxoplasma gondii DPY19 (Dpy19 homolog) functions as a C-mannosyltransferase that modifies thrombospondin type 1 repeat (TSR) domains of the micronemal adhesin MIC2, transferring mannose to tryptophan residues within the WXXWXXC motif. When expressed in a mammalian cell line deficient in C-mannosylation, the T. gondii Dpy19 homolog was able to C-mannosylate TSR-containing adhesins; however, unlike C. elegans or mammalian C-mannosyltransferases, it was inactive on a short WXXW peptide in vitro.","method":"In vitro C-mannosyltransferase assay with peptide substrates; complementation in mammalian C-mannosylation-deficient cell line; mass spectrometry detection of C-hexosylation on MIC2","journal":"Glycobiology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro enzymatic reconstitution with peptide substrates plus functional complementation assay, single lab but multiple orthogonal methods","pmids":["29432542"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2019,"finding":"Deletion of the dpy19 gene in T. gondii abolished C-mannosyltransferase activity and reduced levels of the micronemal protein MIC2, establishing DPY19 as the enzyme responsible for C-mannosylation of TSR-containing proteins in the parasite. Loss of DPY19 activity caused weakened parasite adhesion to host cells, reduced motility, impaired host cell invasion and egress, and strong attenuation of virulence in mice, with the virulence defect exceeding what can be explained by reduced MIC2 alone, indicating that additional substrates are C-mannosylated by DPY19.","method":"Genetic knockout (Δdpy19) with C-mannosyltransferase activity assay, Western blot for MIC2 levels, adhesion assay, motility assay, invasion and egress assays, mouse virulence model","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean gene knockout with multiple orthogonal functional readouts (biochemical activity, protein levels, cell biology assays, in vivo virulence), single lab","pmids":["31862733"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"Toxoplasma gondii DPY19 is a C-mannosyltransferase that transfers α-mannose to tryptophan residues within the WXXWXXC motif of thrombospondin type 1 repeat (TSR)-containing micronemal adhesins (including MIC2), and this modification is required for normal MIC2 protein levels, parasite adhesion to host cells, gliding motility, host cell invasion and egress, and full virulence in vivo."},"narrative":{"mechanistic_narrative":"Toxoplasma gondii DPY19 is a protein C-mannosyltransferase that installs α-mannose on tryptophan residues within the WXXWXXC motif of thrombospondin type 1 repeat (TSR) domains, modifying the micronemal adhesin MIC2 [PMID:29432542]. Genetic deletion of dpy19 abolishes parasite C-mannosyltransferase activity and reduces MIC2 protein levels, establishing DPY19 as the enzyme responsible for TSR C-mannosylation in the parasite [PMID:31862733]. This modification supports parasite adhesion to host cells, gliding motility, host cell invasion and egress, and full virulence in mice; the virulence defect exceeds what reduced MIC2 alone can explain, indicating additional DPY19 substrates beyond MIC2 [PMID:31862733]. Unlike C. elegans or mammalian C-mannosyltransferases, the T. gondii enzyme is inactive on a short WXXW peptide in vitro, a substrate-specificity distinction whose structural basis has not been characterized in the available corpus [PMID:29432542].","teleology":[{"year":2018,"claim":"It was unknown whether the T. gondii Dpy19 homolog possessed C-mannosyltransferase activity; reconstituting the enzyme and detecting the modification established that it transfers mannose to tryptophan within the WXXWXXC motif of MIC2 TSR domains.","evidence":"In vitro C-mannosyltransferase peptide assay, complementation in a mammalian C-mannosylation-deficient cell line, and mass spectrometry of MIC2","pmids":["29432542"],"confidence":"High","gaps":["Structural basis for inactivity on short WXXW peptides versus full TSR domains not resolved","Full substrate repertoire beyond MIC2 not defined","Catalytic mechanism and cofactor requirements not detailed"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2019,"claim":"It was unclear whether DPY19 is the physiological enzyme for TSR C-mannosylation and what its loss costs the parasite; knockout abolished activity, lowered MIC2, and impaired the full invasion program, establishing DPY19 as required for adhesion, motility, invasion, egress and virulence.","evidence":"Δdpy19 knockout with C-mannosyltransferase activity assay, MIC2 Western blot, adhesion/motility/invasion/egress assays, and mouse virulence model","pmids":["31862733"],"confidence":"High","gaps":["Additional C-mannosylated substrates responsible for the excess virulence defect not identified","Mechanistic link between C-mannosylation and MIC2 stability not delineated","How reduced modification translates to weakened adhesion at the molecular level not resolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The identity of DPY19 substrates beyond MIC2 that account for its full contribution to virulence remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No additional C-mannosylated adhesins have been mapped in the corpus","No structural model explaining TSR-specific versus peptide substrate recognition"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["MIC2 (MICRONEMAL TSR-CONTAINING ADHESIN, SUBSTRATE)"],"other_free_text":["C-mannosyltransferase transferring α-mannose to tryptophan in the WXXWXXC motif of TSR domains [#0]","Required for parasite adhesion, gliding motility, host cell invasion and egress [#1]","Required for full virulence in mice, with a defect exceeding that attributable to reduced MIC2 alone, implying additional substrates [#1]","Inactive on short WXXW peptides in vitro, unlike C. elegans and mammalian orthologs [#0]"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"29432542","id":"PMC_29432542","title":"Apicomplexan C-Mannosyltransferases Modify Thrombospondin Type I-containing Adhesins of the TRAP Family.","date":"2018","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/29432542","citation_count":21,"is_preprint":false},{"pmid":"31862733","id":"PMC_31862733","title":"C-Mannosylation of Toxoplasma gondii proteins promotes attachment to host cells and parasite virulence.","date":"2019","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/31862733","citation_count":11,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":3391,"output_tokens":863,"usd":0.011559,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5622,"output_tokens":1700,"usd":0.035305,"stage2_stop_reason":"end_turn"},"total_usd":0.046864,"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\": 2018,\n      \"finding\": \"Toxoplasma gondii DPY19 (Dpy19 homolog) functions as a C-mannosyltransferase that modifies thrombospondin type 1 repeat (TSR) domains of the micronemal adhesin MIC2, transferring mannose to tryptophan residues within the WXXWXXC motif. When expressed in a mammalian cell line deficient in C-mannosylation, the T. gondii Dpy19 homolog was able to C-mannosylate TSR-containing adhesins; however, unlike C. elegans or mammalian C-mannosyltransferases, it was inactive on a short WXXW peptide in vitro.\",\n      \"method\": \"In vitro C-mannosyltransferase assay with peptide substrates; complementation in mammalian C-mannosylation-deficient cell line; mass spectrometry detection of C-hexosylation on MIC2\",\n      \"journal\": \"Glycobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzymatic reconstitution with peptide substrates plus functional complementation assay, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"29432542\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Deletion of the dpy19 gene in T. gondii abolished C-mannosyltransferase activity and reduced levels of the micronemal protein MIC2, establishing DPY19 as the enzyme responsible for C-mannosylation of TSR-containing proteins in the parasite. Loss of DPY19 activity caused weakened parasite adhesion to host cells, reduced motility, impaired host cell invasion and egress, and strong attenuation of virulence in mice, with the virulence defect exceeding what can be explained by reduced MIC2 alone, indicating that additional substrates are C-mannosylated by DPY19.\",\n      \"method\": \"Genetic knockout (Δdpy19) with C-mannosyltransferase activity assay, Western blot for MIC2 levels, adhesion assay, motility assay, invasion and egress assays, mouse virulence model\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean gene knockout with multiple orthogonal functional readouts (biochemical activity, protein levels, cell biology assays, in vivo virulence), single lab\",\n      \"pmids\": [\"31862733\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"Toxoplasma gondii DPY19 is a C-mannosyltransferase that transfers α-mannose to tryptophan residues within the WXXWXXC motif of thrombospondin type 1 repeat (TSR)-containing micronemal adhesins (including MIC2), and this modification is required for normal MIC2 protein levels, parasite adhesion to host cells, gliding motility, host cell invasion and egress, and full virulence in vivo.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"Toxoplasma gondii DPY19 is a protein C-mannosyltransferase that installs α-mannose on tryptophan residues within the WXXWXXC motif of thrombospondin type 1 repeat (TSR) domains, modifying the micronemal adhesin MIC2 [#0]. Genetic deletion of dpy19 abolishes parasite C-mannosyltransferase activity and reduces MIC2 protein levels, establishing DPY19 as the enzyme responsible for TSR C-mannosylation in the parasite [#1]. This modification supports parasite adhesion to host cells, gliding motility, host cell invasion and egress, and full virulence in mice; the virulence defect exceeds what reduced MIC2 alone can explain, indicating additional DPY19 substrates beyond MIC2 [#1]. Unlike C. elegans or mammalian C-mannosyltransferases, the T. gondii enzyme is inactive on a short WXXW peptide in vitro, a substrate-specificity distinction whose structural basis has not been characterized in the available corpus [#0].\",\n  \"teleology\": [\n    {\n      \"year\": 2018,\n      \"claim\": \"It was unknown whether the T. gondii Dpy19 homolog possessed C-mannosyltransferase activity; reconstituting the enzyme and detecting the modification established that it transfers mannose to tryptophan within the WXXWXXC motif of MIC2 TSR domains.\",\n      \"evidence\": \"In vitro C-mannosyltransferase peptide assay, complementation in a mammalian C-mannosylation-deficient cell line, and mass spectrometry of MIC2\",\n      \"pmids\": [\"29432542\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis for inactivity on short WXXW peptides versus full TSR domains not resolved\",\n        \"Full substrate repertoire beyond MIC2 not defined\",\n        \"Catalytic mechanism and cofactor requirements not detailed\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"It was unclear whether DPY19 is the physiological enzyme for TSR C-mannosylation and what its loss costs the parasite; knockout abolished activity, lowered MIC2, and impaired the full invasion program, establishing DPY19 as required for adhesion, motility, invasion, egress and virulence.\",\n      \"evidence\": \"Δdpy19 knockout with C-mannosyltransferase activity assay, MIC2 Western blot, adhesion/motility/invasion/egress assays, and mouse virulence model\",\n      \"pmids\": [\"31862733\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Additional C-mannosylated substrates responsible for the excess virulence defect not identified\",\n        \"Mechanistic link between C-mannosylation and MIC2 stability not delineated\",\n        \"How reduced modification translates to weakened adhesion at the molecular level not resolved\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The identity of DPY19 substrates beyond MIC2 that account for its full contribution to virulence remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No additional C-mannosylated adhesins have been mapped in the corpus\",\n        \"No structural model explaining TSR-specific versus peptide substrate recognition\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0018205\", \"supporting_discovery_ids\": [0, 1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"GO:0006486\", \"supporting_discovery_ids\": [0, 1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"MIC2 (micronemal TSR-containing adhesin, substrate)\"],\n    \"other_free_text\": [\n      \"C-mannosyltransferase transferring α-mannose to tryptophan in the WXXWXXC motif of TSR domains [#0]\",\n      \"Required for parasite adhesion, gliding motility, host cell invasion and egress [#1]\",\n      \"Required for full virulence in mice, with a defect exceeding that attributable to reduced MIC2 alone, implying additional substrates [#1]\",\n      \"Inactive on short WXXW peptides in vitro, unlike C. elegans and mammalian orthologs [#0]\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_280400","name":"DPY19","product":"Dpy-19-like C-mannosyltransferase","uniprot_acc":"A0A125YSP7","chromosome":"TGME49_chrVIIa","start_pos":444954},{"strain":"GT1","gene_id":"TGGT1_280400","name":null,"product":"hypothetical protein","uniprot_acc":null,"chromosome":"TGGT1_chrVIIa","start_pos":425141},{"strain":"RH88","gene_id":"TGRH88_033030","name":null,"product":"unspecified product","uniprot_acc":null,"chromosome":"CM023088","start_pos":506273},{"strain":"VEG","gene_id":"TGVEG_280400","name":null,"product":"Q-cell neuroblast polarisation protein","uniprot_acc":"B9QPM1","chromosome":"TGVEG_chrVIIa","start_pos":487575}]}