{"gene":"TG_253370","gene_symbol":"RON4L1","run_date":"2026-09-08T12:58:25","timeline":{"discoveries":[{"year":2017,"finding":"RON4L1 is a new member of the moving junction (MJ) complex in Toxoplasma gondii; it localizes to the cytosolic face of the host membrane upon secretion during invasion and is associated with the MJ.","method":"Localization by direct imaging during invasion; biochemical association with MJ complex","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct localization experiment with functional context, single lab with multiple orthogonal approaches (localization, KO, sequence analysis)","pmids":["29263399"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"RON4L1 displays sequence similarity with RON4 and is cleaved at its C-terminal end before reaching the rhoptry neck, indicating proteolytic processing as part of its maturation.","method":"Sequence analysis and subcellular fractionation/localization","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single lab, cleavage inferred from localization/sequence data, no in vitro reconstitution of cleavage","pmids":["29263399"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"RON4L1 knock-out parasites are not essential for the lytic cycle in vitro but kill mice less efficiently, establishing a role in virulence in vivo.","method":"Genetic knock-out with in vitro lytic cycle assay and mouse infection model","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean KO with defined phenotypic readouts in vitro and in vivo, single lab","pmids":["29263399"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"RON4L1 trafficking to the MJ is not affected in the absence of RON2, RON4, or RON5, suggesting RON4L1 is part of an independent MJ sub-complex distinct from the canonical RON2/RON4/RON5 complex.","method":"Genetic epistasis using RON2, RON4, and RON5 knock-out or depleted parasites with localization readout","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Moderate — epistasis experiment with localization readout across multiple RON mutant backgrounds, single lab","pmids":["29263399"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"RON4L1 is a coccidian-specific protein, establishing a phylogenetically restricted distribution within Apicomplexa.","method":"Sequence/phylogenetic analysis","journal":"Scientific reports","confidence":"Low","confidence_rationale":"Tier 4 / Weak — computational/comparative sequence analysis only, no functional experiment","pmids":["29263399"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"RON4L1 is a coccidian-specific rhoptry neck protein that is proteolytically processed before reaching the rhoptry neck, and upon secretion during host cell invasion it localizes to the cytosolic face of the host membrane as part of the moving junction complex; it traffics to the MJ independently of RON2, RON4, and RON5, suggesting the existence of at least two independent MJ sub-complexes in Toxoplasma tachyzoites, and while dispensable for the in vitro lytic cycle, it contributes to full virulence in vivo."},"narrative":{"mechanistic_narrative":"RON4L1 is a rhoptry neck protein of Toxoplasma gondii that participates in host cell invasion as a component of the moving junction (MJ) machinery [PMID:29263399]. Upon secretion during invasion, it localizes to the cytosolic face of the host membrane and associates with the MJ complex [PMID:29263399]. It shares sequence similarity with RON4 and undergoes proteolytic cleavage at its C-terminus during maturation before reaching the rhoptry neck [PMID:29263399]. RON4L1 traffics to the MJ independently of the canonical MJ components RON2, RON4, and RON5, indicating that it belongs to a distinct MJ sub-complex and implying at least two independent MJ sub-complexes in tachyzoites [PMID:29263399]. Although dispensable for the in vitro lytic cycle, RON4L1 contributes to full virulence, as knockout parasites kill mice less efficiently [PMID:29263399]. Beyond these findings, the biochemical partners, protease responsible for cleavage, and precise molecular function of RON4L1 have not been characterized in the available corpus.","teleology":[{"year":2017,"claim":"Establishing whether an uncharacterized rhoptry protein belongs to the invasion machinery, this work identified RON4L1 as a new MJ complex member positioned at the cytosolic face of the host membrane during invasion.","evidence":"Direct imaging during invasion and biochemical association with the MJ complex in T. gondii","pmids":["29263399"],"confidence":"High","gaps":["Direct binding partners within the MJ not identified","Molecular activity at the junction undefined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"To understand RON4L1 maturation, sequence and localization analysis showed it is related to RON4 and is proteolytically cleaved at its C-terminus before trafficking to the rhoptry neck.","evidence":"Sequence analysis and subcellular fractionation/localization in T. gondii","pmids":["29263399"],"confidence":"Medium","gaps":["Protease responsible for cleavage unknown","Cleavage not reconstituted in vitro","Functional consequence of processing untested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"To place RON4L1 relative to the canonical MJ complex, epistasis in RON2/RON4/RON5 mutant backgrounds showed its trafficking is independent of these components, defining a separate MJ sub-complex.","evidence":"Genetic epistasis using RON2, RON4, and RON5 knock-out/depleted parasites with localization readout in T. gondii","pmids":["29263399"],"confidence":"High","gaps":["The composition of the RON4L1-containing sub-complex is unresolved","Functional relationship between the two MJ sub-complexes unknown"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"To test physiological importance, knockout parasites revealed RON4L1 is dispensable for the in vitro lytic cycle but required for full virulence, linking the protein to pathogenesis in vivo.","evidence":"Genetic knock-out with in vitro lytic cycle assay and mouse infection model in T. gondii","pmids":["29263399"],"confidence":"High","gaps":["Mechanism connecting RON4L1 loss to attenuated virulence unknown","No invasion-efficiency defect defined at the molecular level"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The molecular activity of RON4L1 at the moving junction, its binding partners, the protease that processes it, and the basis of its virulence contribution remain unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No direct interacting partners identified","No structural model","Protease and processing site uncharacterized"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["Moving junction (MJ) complex (RON4L1-containing sub-complex, independent of RON2/RON4/RON5)"],"partners":[],"other_free_text":["Rhoptry neck protein sharing sequence similarity with RON4 [#1]","Proteolytically cleaved at its C-terminus during maturation before reaching the rhoptry neck [#1]","Traffics to the MJ independently of RON2, RON4, and RON5, implying at least two independent MJ sub-complexes [#3]","Dispensable for the in vitro lytic cycle but required for full virulence in a mouse model [#2]","Coccidian-specific protein with phylogenetically restricted distribution within Apicomplexa (Low confidence) [#4]"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"29263399","id":"PMC_29263399","title":"RON4L1 is a new member of the moving junction complex in Toxoplasma gondii.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/29263399","citation_count":16,"is_preprint":false},{"pmid":"40881926","id":"PMC_40881926","title":"In silico evaluation of Toxoplasma gondii rhoptry neck proteins (TgRONs) for potential immunogenic epitopes.","date":"2025","source":"EXCLI journal","url":"https://pubmed.ncbi.nlm.nih.gov/40881926","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":3431,"output_tokens":1126,"usd":0.013591,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6081,"output_tokens":2018,"usd":0.040427,"stage2_stop_reason":"end_turn"},"total_usd":0.054018,"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\": 2017,\n      \"finding\": \"RON4L1 is a new member of the moving junction (MJ) complex in Toxoplasma gondii; it localizes to the cytosolic face of the host membrane upon secretion during invasion and is associated with the MJ.\",\n      \"method\": \"Localization by direct imaging during invasion; biochemical association with MJ complex\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiment with functional context, single lab with multiple orthogonal approaches (localization, KO, sequence analysis)\",\n      \"pmids\": [\"29263399\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"RON4L1 displays sequence similarity with RON4 and is cleaved at its C-terminal end before reaching the rhoptry neck, indicating proteolytic processing as part of its maturation.\",\n      \"method\": \"Sequence analysis and subcellular fractionation/localization\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single lab, cleavage inferred from localization/sequence data, no in vitro reconstitution of cleavage\",\n      \"pmids\": [\"29263399\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"RON4L1 knock-out parasites are not essential for the lytic cycle in vitro but kill mice less efficiently, establishing a role in virulence in vivo.\",\n      \"method\": \"Genetic knock-out with in vitro lytic cycle assay and mouse infection model\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined phenotypic readouts in vitro and in vivo, single lab\",\n      \"pmids\": [\"29263399\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"RON4L1 trafficking to the MJ is not affected in the absence of RON2, RON4, or RON5, suggesting RON4L1 is part of an independent MJ sub-complex distinct from the canonical RON2/RON4/RON5 complex.\",\n      \"method\": \"Genetic epistasis using RON2, RON4, and RON5 knock-out or depleted parasites with localization readout\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis experiment with localization readout across multiple RON mutant backgrounds, single lab\",\n      \"pmids\": [\"29263399\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"RON4L1 is a coccidian-specific protein, establishing a phylogenetically restricted distribution within Apicomplexa.\",\n      \"method\": \"Sequence/phylogenetic analysis\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — computational/comparative sequence analysis only, no functional experiment\",\n      \"pmids\": [\"29263399\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"RON4L1 is a coccidian-specific rhoptry neck protein that is proteolytically processed before reaching the rhoptry neck, and upon secretion during host cell invasion it localizes to the cytosolic face of the host membrane as part of the moving junction complex; it traffics to the MJ independently of RON2, RON4, and RON5, suggesting the existence of at least two independent MJ sub-complexes in Toxoplasma tachyzoites, and while dispensable for the in vitro lytic cycle, it contributes to full virulence in vivo.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"RON4L1 is a rhoptry neck protein of Toxoplasma gondii that participates in host cell invasion as a component of the moving junction (MJ) machinery [#0]. Upon secretion during invasion, it localizes to the cytosolic face of the host membrane and associates with the MJ complex [#0]. It shares sequence similarity with RON4 and undergoes proteolytic cleavage at its C-terminus during maturation before reaching the rhoptry neck [#1]. RON4L1 traffics to the MJ independently of the canonical MJ components RON2, RON4, and RON5, indicating that it belongs to a distinct MJ sub-complex and implying at least two independent MJ sub-complexes in tachyzoites [#3]. Although dispensable for the in vitro lytic cycle, RON4L1 contributes to full virulence, as knockout parasites kill mice less efficiently [#2]. Beyond these findings, the biochemical partners, protease responsible for cleavage, and precise molecular function of RON4L1 have not been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Establishing whether an uncharacterized rhoptry protein belongs to the invasion machinery, this work identified RON4L1 as a new MJ complex member positioned at the cytosolic face of the host membrane during invasion.\",\n      \"evidence\": \"Direct imaging during invasion and biochemical association with the MJ complex in T. gondii\",\n      \"pmids\": [\"29263399\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct binding partners within the MJ not identified\", \"Molecular activity at the junction undefined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"To understand RON4L1 maturation, sequence and localization analysis showed it is related to RON4 and is proteolytically cleaved at its C-terminus before trafficking to the rhoptry neck.\",\n      \"evidence\": \"Sequence analysis and subcellular fractionation/localization in T. gondii\",\n      \"pmids\": [\"29263399\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Protease responsible for cleavage unknown\", \"Cleavage not reconstituted in vitro\", \"Functional consequence of processing untested\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"To place RON4L1 relative to the canonical MJ complex, epistasis in RON2/RON4/RON5 mutant backgrounds showed its trafficking is independent of these components, defining a separate MJ sub-complex.\",\n      \"evidence\": \"Genetic epistasis using RON2, RON4, and RON5 knock-out/depleted parasites with localization readout in T. gondii\",\n      \"pmids\": [\"29263399\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The composition of the RON4L1-containing sub-complex is unresolved\", \"Functional relationship between the two MJ sub-complexes unknown\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"To test physiological importance, knockout parasites revealed RON4L1 is dispensable for the in vitro lytic cycle but required for full virulence, linking the protein to pathogenesis in vivo.\",\n      \"evidence\": \"Genetic knock-out with in vitro lytic cycle assay and mouse infection model in T. gondii\",\n      \"pmids\": [\"29263399\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism connecting RON4L1 loss to attenuated virulence unknown\", \"No invasion-efficiency defect defined at the molecular level\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular activity of RON4L1 at the moving junction, its binding partners, the protease that processes it, and the basis of its virulence contribution remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No direct interacting partners identified\", \"No structural model\", \"Protease and processing site uncharacterized\"],\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, 1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0044409\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [\"Moving junction (MJ) complex (RON4L1-containing sub-complex, independent of RON2/RON4/RON5)\"],\n    \"partners\": [],\n    \"other_free_text\": [\n      \"Rhoptry neck protein sharing sequence similarity with RON4 [#1]\",\n      \"Proteolytically cleaved at its C-terminus during maturation before reaching the rhoptry neck [#1]\",\n      \"Traffics to the MJ independently of RON2, RON4, and RON5, implying at least two independent MJ sub-complexes [#3]\",\n      \"Dispensable for the in vitro lytic cycle but required for full virulence in a mouse model [#2]\",\n      \"Coccidian-specific protein with phylogenetically restricted distribution within Apicomplexa (Low confidence) [#4]\"\n    ]\n  },\n  \"strain_conflicts\": []\n}\n```","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_253370","name":"RON4L1","product":"rhoptry neck protein RON4L1","uniprot_acc":"S8GTD8","chromosome":"TGME49_chrIII","start_pos":880008},{"strain":"GT1","gene_id":"TGGT1_253370","name":null,"product":"hypothetical protein","uniprot_acc":null,"chromosome":"TGGT1_chrIII","start_pos":861500},{"strain":"RH88","gene_id":"TGRH88_004940","name":null,"product":"unspecified product","uniprot_acc":null,"chromosome":"CM023084","start_pos":1703958},{"strain":"VEG","gene_id":"TGVEG_253370","name":null,"product":"hypothetical protein","uniprot_acc":"V4ZDB4","chromosome":"TGVEG_chrIII","start_pos":888909}]}