{"gene":"TG_297900","gene_symbol":"GRA83","run_date":"2026-09-08T15:15:12","timeline":{"discoveries":[{"year":2023,"finding":"GRA83 localizes to the parasitophorous vacuole (PV) in both tachyzoites and bradyzoites, established by direct localization experiments.","method":"Direct localization (immunofluorescence assay / microscopy)","journal":"mSphere","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single lab, localization demonstrated in both life stages but no functional consequence directly linked to the PV localization per se","pmids":["37768053"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"finding":"Disruption of GRA83 (∆gra83) causes murine macrophages infected in vitro to produce less IL-12, and in vivo results in reduced IL-12 and IFN-γ, demonstrating that GRA83 is required for stimulating host innate cytokine responses.","method":"Genetic knockout (∆gra83), in vitro macrophage infection assay (IL-12 ELISA), in vivo infection with cytokine measurement","journal":"mSphere","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular phenotype (IL-12 production), confirmed both in vitro and in vivo with multiple orthogonal readouts, single lab","pmids":["37768053"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"finding":"GRA83 promotes nuclear translocation of the p65 subunit of NF-κB in host cells; loss of GRA83 reduces p65 nuclear translocation.","method":"Genetic knockout (∆gra83), nuclear translocation assay for p65","journal":"mSphere","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — single lab, single method (p65 nuclear translocation assay) in KO parasites","pmids":["37768053"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"finding":"Genetic epistasis analysis using ∆gra83/∆gra15 double-knockout parasites showed no further reduction in p65 nuclear translocation compared to single knockouts, indicating GRA83 and GRA15 function in converging (not independent additive) pathways to regulate NF-κB.","method":"Double-knockout epistasis (∆gra83/∆gra15), p65 nuclear translocation assay","journal":"mSphere","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — clean double-KO epistasis with defined readout, single lab, single method","pmids":["37768053"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"finding":"Proximity labeling experiments identified candidate T. gondii-derived interacting partners of GRA83, providing a biochemical interaction map for this effector.","method":"Proximity labeling (BioID or similar)","journal":"mSphere","confidence":"Low","confidence_rationale":"Tier 3 / Weak — proximity labeling identifies candidates but partners are not validated by reciprocal methods; single lab","pmids":["37768053"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"GRA83 is a dense granule effector protein that localizes to the parasitophorous vacuole in both tachyzoites and bradyzoites, and functions to stimulate host innate immunity by promoting NF-κB p65 nuclear translocation and IL-12/IFN-γ production in infected macrophages, operating in converging pathways with GRA15 to regulate host NF-κB activity and thereby limit parasite burden during both acute and chronic infection."},"narrative":{"mechanistic_narrative":"GRA83 is a Toxoplasma gondii dense granule effector that localizes to the parasitophorous vacuole in both tachyzoites and bradyzoites and acts to stimulate host innate immunity during infection [PMID:37768053]. Genetic disruption of GRA83 reduces host IL-12 production by infected macrophages in vitro and lowers both IL-12 and IFN-γ in vivo, establishing GRA83 as required for driving host innate cytokine responses [PMID:37768053]. Mechanistically, GRA83 promotes nuclear translocation of the NF-κB p65 subunit in host cells, and epistasis analysis with ∆gra83/∆gra15 double knockouts shows no additive loss of p65 translocation, placing GRA83 and GRA15 in converging pathways that regulate host NF-κB activity [PMID:37768053]. The direct effectors mediating p65 translocation are uncharacterized: proximity labeling has identified only candidate parasite-derived interacting partners not yet validated by orthogonal methods [PMID:37768053].","teleology":[{"year":2023,"claim":"Establishing where GRA83 resides was the first step in defining it as a secreted effector; localization to the parasitophorous vacuole across both life stages positioned it at the host-parasite interface in acute and chronic infection.","evidence":"Immunofluorescence localization in tachyzoites and bradyzoites","pmids":["37768053"],"confidence":"Medium","gaps":["No functional consequence directly tied to PV localization","Whether GRA83 is exported beyond the PV membrane into the host cell is not resolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"claim":"Whether GRA83 shapes host immunity was answered by knockout, which showed GRA83 is required for infected macrophages to mount IL-12 responses and for downstream IL-12/IFN-γ production in vivo, defining a role in innate cytokine stimulation.","evidence":"∆gra83 knockout with in vitro macrophage IL-12 ELISA and in vivo cytokine measurement","pmids":["37768053"],"confidence":"High","gaps":["Molecular mechanism linking GRA83 to cytokine gene induction not defined","Effect on parasite burden and host survival not fully quantified in this entry"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"claim":"The signaling node engaged by GRA83 was identified as NF-κB: loss of GRA83 reduces p65 nuclear translocation, connecting the cytokine phenotype to a defined host transcriptional pathway.","evidence":"p65 nuclear translocation assay in ∆gra83-infected host cells","pmids":["37768053"],"confidence":"Medium","gaps":["Single method for a single readout","Direct molecular target of GRA83 in the NF-κB cascade unknown"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"claim":"Whether GRA83 acts independently of the known NF-κB effector GRA15 was tested by double-knockout epistasis, which showed no additive loss and placed the two effectors in converging rather than parallel pathways.","evidence":"∆gra83/∆gra15 double-knockout epistasis with p65 nuclear translocation readout","pmids":["37768053"],"confidence":"Medium","gaps":["Point of convergence in the NF-κB pathway not mapped","Single lab, single readout"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"claim":"To identify the biochemical basis of GRA83 action, proximity labeling generated a candidate interactome, providing the first list of potential partners to test.","evidence":"Proximity labeling (BioID or similar) identifying T. gondii-derived candidate partners","pmids":["37768053"],"confidence":"Low","gaps":["Candidate partners not validated by reciprocal Co-IP or independent methods","No host-cell interacting partners defined","Functional relevance of candidates to NF-κB activation untested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The direct molecular mechanism by which GRA83 promotes p65 nuclear translocation and converges with GRA15 remains unknown, including the identity of validated host or parasite partners that transduce the signal.","evidence":"No direct experimental evidence in the available corpus","pmids":[],"confidence":"Low","gaps":["No validated direct interactor","Convergence point with GRA15 not molecularly defined","No structural or biochemical activity assigned to GRA83"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["GRA15 (CONVERGING PATHWAY, NOT DIRECT PHYSICAL INTERACTION)","CANDIDATE T. GONDII-DERIVED PARTNERS FROM PROXIMITY LABELING (UNVALIDATED)"],"other_free_text":["Dense granule effector secreted to the parasitophorous vacuole in both tachyzoites and bradyzoites [#0].","Required for host IL-12 production by infected macrophages in vitro and for IL-12/IFN-γ responses in vivo [#1].","Promotes host NF-κB p65 nuclear translocation and functions in a pathway converging with GRA15 [#2, #3]."]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"37768053","id":"PMC_37768053","title":"The Toxoplasma gondii effector GRA83 modulates the host's innate immune response to regulate parasite infection.","date":"2023","source":"mSphere","url":"https://pubmed.ncbi.nlm.nih.gov/37768053","citation_count":9,"is_preprint":false},{"pmid":"37398161","id":"PMC_37398161","title":"The Toxoplasma gondii effector GRA83 modulates the host's innate immune response to regulate parasite infection.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/37398161","citation_count":2,"is_preprint":false},{"pmid":"41441646","id":"PMC_41441646","title":"Protective Efficacy of Two Novel DNA Vaccine Candidates Encoding TgGRA28 and TgGRA83 with an IL-28B Molecular Adjuvant Against Acute and Chronic Toxoplasmosis in Mice.","date":"2025","source":"Vaccines","url":"https://pubmed.ncbi.nlm.nih.gov/41441646","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4797,"output_tokens":1158,"usd":0.01588,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6134,"output_tokens":2351,"usd":0.044722,"stage2_stop_reason":"end_turn"},"total_usd":0.060602,"stage1_batch_id":"msgbatch_01S6GjoYQm8LTPUsdhASdqag","stage2_batch_id":"msgbatch_01VX63RTMdBJqsG6gQMqoCjz","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2023,\n      \"finding\": \"GRA83 localizes to the parasitophorous vacuole (PV) in both tachyzoites and bradyzoites, established by direct localization experiments.\",\n      \"method\": \"Direct localization (immunofluorescence assay / microscopy)\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single lab, localization demonstrated in both life stages but no functional consequence directly linked to the PV localization per se\",\n      \"pmids\": [\"37768053\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Disruption of GRA83 (∆gra83) causes murine macrophages infected in vitro to produce less IL-12, and in vivo results in reduced IL-12 and IFN-γ, demonstrating that GRA83 is required for stimulating host innate cytokine responses.\",\n      \"method\": \"Genetic knockout (∆gra83), in vitro macrophage infection assay (IL-12 ELISA), in vivo infection with cytokine measurement\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular phenotype (IL-12 production), confirmed both in vitro and in vivo with multiple orthogonal readouts, single lab\",\n      \"pmids\": [\"37768053\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"GRA83 promotes nuclear translocation of the p65 subunit of NF-κB in host cells; loss of GRA83 reduces p65 nuclear translocation.\",\n      \"method\": \"Genetic knockout (∆gra83), nuclear translocation assay for p65\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — single lab, single method (p65 nuclear translocation assay) in KO parasites\",\n      \"pmids\": [\"37768053\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Genetic epistasis analysis using ∆gra83/∆gra15 double-knockout parasites showed no further reduction in p65 nuclear translocation compared to single knockouts, indicating GRA83 and GRA15 function in converging (not independent additive) pathways to regulate NF-κB.\",\n      \"method\": \"Double-knockout epistasis (∆gra83/∆gra15), p65 nuclear translocation assay\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — clean double-KO epistasis with defined readout, single lab, single method\",\n      \"pmids\": [\"37768053\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Proximity labeling experiments identified candidate T. gondii-derived interacting partners of GRA83, providing a biochemical interaction map for this effector.\",\n      \"method\": \"Proximity labeling (BioID or similar)\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — proximity labeling identifies candidates but partners are not validated by reciprocal methods; single lab\",\n      \"pmids\": [\"37768053\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"GRA83 is a dense granule effector protein that localizes to the parasitophorous vacuole in both tachyzoites and bradyzoites, and functions to stimulate host innate immunity by promoting NF-κB p65 nuclear translocation and IL-12/IFN-γ production in infected macrophages, operating in converging pathways with GRA15 to regulate host NF-κB activity and thereby limit parasite burden during both acute and chronic infection.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GRA83 is a Toxoplasma gondii dense granule effector that localizes to the parasitophorous vacuole in both tachyzoites and bradyzoites and acts to stimulate host innate immunity during infection [#0, #1]. Genetic disruption of GRA83 reduces host IL-12 production by infected macrophages in vitro and lowers both IL-12 and IFN-\\u03b3 in vivo, establishing GRA83 as required for driving host innate cytokine responses [#1]. Mechanistically, GRA83 promotes nuclear translocation of the NF-\\u03baB p65 subunit in host cells, and epistasis analysis with \\u2206gra83/\\u2206gra15 double knockouts shows no additive loss of p65 translocation, placing GRA83 and GRA15 in converging pathways that regulate host NF-\\u03baB activity [#2, #3]. The direct effectors mediating p65 translocation are uncharacterized: proximity labeling has identified only candidate parasite-derived interacting partners not yet validated by orthogonal methods [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 2023,\n      \"claim\": \"Establishing where GRA83 resides was the first step in defining it as a secreted effector; localization to the parasitophorous vacuole across both life stages positioned it at the host-parasite interface in acute and chronic infection.\",\n      \"evidence\": \"Immunofluorescence localization in tachyzoites and bradyzoites\",\n      \"pmids\": [\"37768053\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional consequence directly tied to PV localization\", \"Whether GRA83 is exported beyond the PV membrane into the host cell is not resolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Whether GRA83 shapes host immunity was answered by knockout, which showed GRA83 is required for infected macrophages to mount IL-12 responses and for downstream IL-12/IFN-\\u03b3 production in vivo, defining a role in innate cytokine stimulation.\",\n      \"evidence\": \"\\u2206gra83 knockout with in vitro macrophage IL-12 ELISA and in vivo cytokine measurement\",\n      \"pmids\": [\"37768053\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism linking GRA83 to cytokine gene induction not defined\", \"Effect on parasite burden and host survival not fully quantified in this entry\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"The signaling node engaged by GRA83 was identified as NF-\\u03baB: loss of GRA83 reduces p65 nuclear translocation, connecting the cytokine phenotype to a defined host transcriptional pathway.\",\n      \"evidence\": \"p65 nuclear translocation assay in \\u2206gra83-infected host cells\",\n      \"pmids\": [\"37768053\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single method for a single readout\", \"Direct molecular target of GRA83 in the NF-\\u03baB cascade unknown\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Whether GRA83 acts independently of the known NF-\\u03baB effector GRA15 was tested by double-knockout epistasis, which showed no additive loss and placed the two effectors in converging rather than parallel pathways.\",\n      \"evidence\": \"\\u2206gra83/\\u2206gra15 double-knockout epistasis with p65 nuclear translocation readout\",\n      \"pmids\": [\"37768053\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Point of convergence in the NF-\\u03baB pathway not mapped\", \"Single lab, single readout\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"To identify the biochemical basis of GRA83 action, proximity labeling generated a candidate interactome, providing the first list of potential partners to test.\",\n      \"evidence\": \"Proximity labeling (BioID or similar) identifying T. gondii-derived candidate partners\",\n      \"pmids\": [\"37768053\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Candidate partners not validated by reciprocal Co-IP or independent methods\", \"No host-cell interacting partners defined\", \"Functional relevance of candidates to NF-\\u03baB activation untested\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The direct molecular mechanism by which GRA83 promotes p65 nuclear translocation and converges with GRA15 remains unknown, including the identity of validated host or parasite partners that transduce the signal.\",\n      \"evidence\": \"No direct experimental evidence in the available corpus\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No validated direct interactor\", \"Convergence point with GRA15 not molecularly defined\", \"No structural or biochemical activity assigned to GRA83\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0020003\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0038061\", \"supporting_discovery_ids\": [2, 3], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0045089\", \"supporting_discovery_ids\": [1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"GRA15 (converging pathway, not direct physical interaction)\", \"Candidate T. gondii-derived partners from proximity labeling (unvalidated)\"],\n    \"other_free_text\": [\n      \"Dense granule effector secreted to the parasitophorous vacuole in both tachyzoites and bradyzoites [#0].\",\n      \"Required for host IL-12 production by infected macrophages in vitro and for IL-12/IFN-\\u03b3 responses in vivo [#1].\",\n      \"Promotes host NF-\\u03baB p65 nuclear translocation and functions in a pathway converging with GRA15 [#2, #3].\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_297900","name":"GRA83","product":"dense granule protein GRA83","uniprot_acc":"S8GK08","chromosome":"TGME49_chrII","start_pos":2102968},{"strain":"GT1","gene_id":"TGGT1_297900","name":null,"product":"hypothetical protein","uniprot_acc":null,"chromosome":"TGGT1_chrII","start_pos":2079614},{"strain":"RH88","gene_id":"TGRH88_002680","name":null,"product":"unspecified product","uniprot_acc":null,"chromosome":"CM023083","start_pos":2279036},{"strain":"VEG","gene_id":"TGVEG_297900","name":null,"product":"hypothetical protein","uniprot_acc":"B9Q180","chromosome":"TGVEG_chrII","start_pos":2113408}]}