{"gene":"TG_214470","gene_symbol":"ULP1","run_date":"2026-09-08T11:06:27","timeline":{"discoveries":[{"year":2018,"finding":"Recombinant TgUlp1 is an active SUMO protease (desumoylase) capable of removing SUMO from a sumoylated substrate in vitro, and functionally complements a yeast Ulp1 knockout, establishing it as the first committed enzyme in the T. gondii sumoylation/desumoylation pathway.","method":"Functional complementation in yeast (Ulp1 knockout rescue), in vitro enzymatic desumoylation assay with recombinant TgUlp1","journal":"International journal for parasitology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro enzymatic assay plus cross-species functional complementation, two orthogonal methods in one study","pmids":["30005881"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2018,"finding":"TgUlp1 expression and enzymatic activity are post-transcriptionally regulated by Tg-miR-60 (the most abundant miRNA in T. gondii type 1 strain); inhibition of Tg-miR-60 increases TgUlp1 expression and desumoylase activity and affects parasite growth fitness.","method":"Transgenic epitope-tagged TgUlp1 strain; miR-60 inhibitor transfection; measurement of TgUlp1 expression and enzymatic activity; parasite growth assay","journal":"International journal for parasitology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional modulation with functional readout, single lab, two orthogonal methods (expression + enzyme activity)","pmids":["30005881"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"finding":"ULP1 localizes to the Toxoplasma Golgi apparatus and is structurally similar to the eukaryotic trafficking factor p115/Uso1; conditional depletion of ULP1 causes defects in microneme secretion, invasion, replication, and egress, demonstrating an essential role in the secretory pathway.","method":"Subcellular localization (fluorescence microscopy), conditional knockdown (auxin-inducible degron or similar), phenotypic assays for microneme secretion, invasion, replication, and egress","journal":"mBio","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct localization experiment combined with conditional knockdown and multiple orthogonal phenotypic readouts; published peer-reviewed and confirmed in preprint","pmids":["39345210","38352341"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"finding":"ULP1 physically interacts with the T. gondii conserved oligomeric Golgi (COG) complex, as demonstrated by TurboID proximity labeling and immunoprecipitation, and proximity labeling with ULP1 as bait identified 11 additional Golgi-associated proteins.","method":"TurboID proximity labeling with ULP1 as bait; immunoprecipitation/mass spectrometry","journal":"mBio","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal proximity labeling and IP in single lab; strong experimental approach but single study","pmids":["39345210","38352341"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"Toxoplasma gondii ULP1 is a Golgi-localized protein with dual mechanistic roles: (1) as an active SUMO protease (desumoylase) that processes SUMO substrates and is regulated by Tg-miR-60, and (2) as a p115/Uso1-like trafficking factor at the Golgi that interacts with the COG complex and is essential for microneme secretion, host cell invasion, intracellular replication, and egress."},"narrative":{"mechanistic_narrative":"Toxoplasma gondii ULP1 is a Golgi-associated protein that couples SUMO-substrate processing to the parasite's secretory trafficking machinery [PMID:30005881, PMID:39345210, PMID:38352341]. Recombinant TgUlp1 acts as an active SUMO protease (desumoylase) that removes SUMO from a sumoylated substrate in vitro and functionally rescues a yeast Ulp1 knockout, establishing it as a committed enzyme of the T. gondii sumoylation/desumoylation pathway [PMID:30005881]; its expression and desumoylase activity are post-transcriptionally restrained by the abundant miRNA Tg-miR-60, whose inhibition raises TgUlp1 levels and activity and alters parasite growth fitness [PMID:30005881]. In parallel, ULP1 localizes to the Golgi apparatus, is structurally similar to the trafficking factor p115/Uso1, and physically associates with the conserved oligomeric Golgi (COG) complex [PMID:39345210, PMID:38352341]. Conditional depletion of ULP1 disrupts microneme secretion, host-cell invasion, intracellular replication, and egress, defining an essential role in the secretory pathway [PMID:39345210, PMID:38352341].","teleology":[{"year":2018,"claim":"Whether T. gondii possessed a dedicated enzyme to reverse sumoylation was unknown; identifying an active desumoylase established the committed catalytic step of the parasite SUMO pathway.","evidence":"In vitro desumoylation assay with recombinant TgUlp1 plus functional complementation of a yeast Ulp1 knockout","pmids":["30005881"],"confidence":"High","gaps":["Physiological SUMO substrates in T. gondii not identified","No structural characterization of the catalytic domain","Whether desumoylase activity is required for the trafficking phenotype not tested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2018,"claim":"How TgUlp1 activity is tuned in the parasite was unknown; showing post-transcriptional control by Tg-miR-60 established a regulatory layer over desumoylase output.","evidence":"Epitope-tagged transgenic strain with miR-60 inhibitor transfection, expression and enzymatic activity measurement, and growth assay","pmids":["30005881"],"confidence":"Medium","gaps":["Direct miRNA-target binding at the TgUlp1 transcript not mapped in detail","Mechanism linking altered activity to growth fitness unresolved","Regulation across strains and life stages not examined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"claim":"The cellular role of ULP1 beyond catalysis was unknown; localization plus conditional depletion established it as an essential Golgi secretory-pathway factor resembling p115/Uso1.","evidence":"Fluorescence localization and conditional knockdown with phenotypic assays for microneme secretion, invasion, replication, and egress","pmids":["39345210","38352341"],"confidence":"High","gaps":["Whether secretory defects depend on desumoylase catalytic activity untested","Molecular step in trafficking that ULP1 executes not defined","Relationship between the SUMO-protease and p115/Uso1-like functions unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"claim":"The molecular context of ULP1 at the Golgi was unknown; proximity labeling identified the COG complex and additional Golgi proteins as its interaction network.","evidence":"TurboID proximity labeling with ULP1 as bait and immunoprecipitation/mass spectrometry","pmids":["39345210","38352341"],"confidence":"Medium","gaps":["Direct versus proximity-based interaction with COG subunits not distinguished","Functional consequence of each of the 11 additional Golgi partners not tested","Reciprocal validation from COG side not reported"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"It remains unknown whether ULP1's desumoylase activity and its p115/Uso1-like Golgi trafficking role are mechanistically coupled or represent separable functions.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No experiment separating catalytic-dead from trafficking-competent ULP1","SUMO substrates within the secretory pathway not identified","No structural model reconciling protease and Uso1-like activities"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["Conserved oligomeric Golgi (COG) complex (interaction partner)"],"partners":["COG COMPLEX","11 ADDITIONAL GOLGI-ASSOCIATED PROTEINS (TURBOID PROXIMITY NETWORK)"],"other_free_text":["Recombinant TgUlp1 rescues a yeast Ulp1 knockout, indicating cross-species conservation of desumoylase function [#0]","Structurally similar to the trafficking factor p115/Uso1 [#2]","Post-transcriptionally regulated by Tg-miR-60, the most abundant miRNA in a T. gondii type 1 strain [#1]","Conditional depletion impairs microneme secretion, invasion, replication, and egress [#2]"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"39345210","id":"PMC_39345210","title":"Characterization and functional analysis of Toxoplasma Golgi-associated proteins identified by proximity labeling.","date":"2024","source":"mBio","url":"https://pubmed.ncbi.nlm.nih.gov/39345210","citation_count":8,"is_preprint":false},{"pmid":"30005881","id":"PMC_30005881","title":"Toxoplasma ubiquitin-like protease 1, a key enzyme in sumoylation and desumoylation pathways, is under the control of non-coding RNAs.","date":"2018","source":"International journal for parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/30005881","citation_count":8,"is_preprint":false},{"pmid":"33011210","id":"PMC_33011210","title":"Characterization of natural antisense transcripts arisen from the locus encoding Toxoplasma gondii ubiquitin-like protease.","date":"2020","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/33011210","citation_count":2,"is_preprint":false},{"pmid":"38352341","id":"PMC_38352341","title":"Characterization and functional analysis of Toxoplasma Golgi-associated proteins identified by proximity labelling.","date":"2024","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/38352341","citation_count":1,"is_preprint":false},{"pmid":"40086715","id":"PMC_40086715","title":"Involvement of Toxoplasma gondii natural antisense transcripts in cellular stress responses.","date":"2025","source":"Experimental parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/40086715","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":5398,"output_tokens":1177,"usd":0.016924,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6082,"output_tokens":2502,"usd":0.04648,"stage2_stop_reason":"end_turn"},"total_usd":0.063404,"stage1_batch_id":"msgbatch_01WokvBYTB6JLnYrpD4rXnyV","stage2_batch_id":"msgbatch_01M7hsQDvz6AqVC9DLVjQzzc","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2018,\n      \"finding\": \"Recombinant TgUlp1 is an active SUMO protease (desumoylase) capable of removing SUMO from a sumoylated substrate in vitro, and functionally complements a yeast Ulp1 knockout, establishing it as the first committed enzyme in the T. gondii sumoylation/desumoylation pathway.\",\n      \"method\": \"Functional complementation in yeast (Ulp1 knockout rescue), in vitro enzymatic desumoylation assay with recombinant TgUlp1\",\n      \"journal\": \"International journal for parasitology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzymatic assay plus cross-species functional complementation, two orthogonal methods in one study\",\n      \"pmids\": [\"30005881\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"TgUlp1 expression and enzymatic activity are post-transcriptionally regulated by Tg-miR-60 (the most abundant miRNA in T. gondii type 1 strain); inhibition of Tg-miR-60 increases TgUlp1 expression and desumoylase activity and affects parasite growth fitness.\",\n      \"method\": \"Transgenic epitope-tagged TgUlp1 strain; miR-60 inhibitor transfection; measurement of TgUlp1 expression and enzymatic activity; parasite growth assay\",\n      \"journal\": \"International journal for parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional modulation with functional readout, single lab, two orthogonal methods (expression + enzyme activity)\",\n      \"pmids\": [\"30005881\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ULP1 localizes to the Toxoplasma Golgi apparatus and is structurally similar to the eukaryotic trafficking factor p115/Uso1; conditional depletion of ULP1 causes defects in microneme secretion, invasion, replication, and egress, demonstrating an essential role in the secretory pathway.\",\n      \"method\": \"Subcellular localization (fluorescence microscopy), conditional knockdown (auxin-inducible degron or similar), phenotypic assays for microneme secretion, invasion, replication, and egress\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct localization experiment combined with conditional knockdown and multiple orthogonal phenotypic readouts; published peer-reviewed and confirmed in preprint\",\n      \"pmids\": [\"39345210\", \"38352341\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ULP1 physically interacts with the T. gondii conserved oligomeric Golgi (COG) complex, as demonstrated by TurboID proximity labeling and immunoprecipitation, and proximity labeling with ULP1 as bait identified 11 additional Golgi-associated proteins.\",\n      \"method\": \"TurboID proximity labeling with ULP1 as bait; immunoprecipitation/mass spectrometry\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal proximity labeling and IP in single lab; strong experimental approach but single study\",\n      \"pmids\": [\"39345210\", \"38352341\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"Toxoplasma gondii ULP1 is a Golgi-localized protein with dual mechanistic roles: (1) as an active SUMO protease (desumoylase) that processes SUMO substrates and is regulated by Tg-miR-60, and (2) as a p115/Uso1-like trafficking factor at the Golgi that interacts with the COG complex and is essential for microneme secretion, host cell invasion, intracellular replication, and egress.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"Toxoplasma gondii ULP1 is a Golgi-associated protein that couples SUMO-substrate processing to the parasite's secretory trafficking machinery [#0, #2]. Recombinant TgUlp1 acts as an active SUMO protease (desumoylase) that removes SUMO from a sumoylated substrate in vitro and functionally rescues a yeast Ulp1 knockout, establishing it as a committed enzyme of the T. gondii sumoylation/desumoylation pathway [#0]; its expression and desumoylase activity are post-transcriptionally restrained by the abundant miRNA Tg-miR-60, whose inhibition raises TgUlp1 levels and activity and alters parasite growth fitness [#1]. In parallel, ULP1 localizes to the Golgi apparatus, is structurally similar to the trafficking factor p115/Uso1, and physically associates with the conserved oligomeric Golgi (COG) complex [#2, #3]. Conditional depletion of ULP1 disrupts microneme secretion, host-cell invasion, intracellular replication, and egress, defining an essential role in the secretory pathway [#2].\",\n  \"teleology\": [\n    {\n      \"year\": 2018,\n      \"claim\": \"Whether T. gondii possessed a dedicated enzyme to reverse sumoylation was unknown; identifying an active desumoylase established the committed catalytic step of the parasite SUMO pathway.\",\n      \"evidence\": \"In vitro desumoylation assay with recombinant TgUlp1 plus functional complementation of a yeast Ulp1 knockout\",\n      \"pmids\": [\"30005881\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Physiological SUMO substrates in T. gondii not identified\",\n        \"No structural characterization of the catalytic domain\",\n        \"Whether desumoylase activity is required for the trafficking phenotype not tested\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"How TgUlp1 activity is tuned in the parasite was unknown; showing post-transcriptional control by Tg-miR-60 established a regulatory layer over desumoylase output.\",\n      \"evidence\": \"Epitope-tagged transgenic strain with miR-60 inhibitor transfection, expression and enzymatic activity measurement, and growth assay\",\n      \"pmids\": [\"30005881\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Direct miRNA-target binding at the TgUlp1 transcript not mapped in detail\",\n        \"Mechanism linking altered activity to growth fitness unresolved\",\n        \"Regulation across strains and life stages not examined\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"The cellular role of ULP1 beyond catalysis was unknown; localization plus conditional depletion established it as an essential Golgi secretory-pathway factor resembling p115/Uso1.\",\n      \"evidence\": \"Fluorescence localization and conditional knockdown with phenotypic assays for microneme secretion, invasion, replication, and egress\",\n      \"pmids\": [\"39345210\", \"38352341\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether secretory defects depend on desumoylase catalytic activity untested\",\n        \"Molecular step in trafficking that ULP1 executes not defined\",\n        \"Relationship between the SUMO-protease and p115/Uso1-like functions unresolved\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"The molecular context of ULP1 at the Golgi was unknown; proximity labeling identified the COG complex and additional Golgi proteins as its interaction network.\",\n      \"evidence\": \"TurboID proximity labeling with ULP1 as bait and immunoprecipitation/mass spectrometry\",\n      \"pmids\": [\"39345210\", \"38352341\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Direct versus proximity-based interaction with COG subunits not distinguished\",\n        \"Functional consequence of each of the 11 additional Golgi partners not tested\",\n        \"Reciprocal validation from COG side not reported\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown whether ULP1's desumoylase activity and its p115/Uso1-like Golgi trafficking role are mechanistically coupled or represent separable functions.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No experiment separating catalytic-dead from trafficking-competent ULP1\",\n        \"SUMO substrates within the secretory pathway not identified\",\n        \"No structural model reconciling protease and Uso1-like activities\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016929\", \"supporting_discovery_ids\": [0, 1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0008233\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [2, 3], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0016925\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0006888\", \"supporting_discovery_ids\": [2, 3], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0046718\", \"supporting_discovery_ids\": [2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [\n      \"Conserved oligomeric Golgi (COG) complex (interaction partner)\"\n    ],\n    \"partners\": [\n      \"COG complex\",\n      \"11 additional Golgi-associated proteins (TurboID proximity network)\"\n    ],\n    \"other_free_text\": [\n      \"Recombinant TgUlp1 rescues a yeast Ulp1 knockout, indicating cross-species conservation of desumoylase function [#0]\",\n      \"Structurally similar to the trafficking factor p115/Uso1 [#2]\",\n      \"Post-transcriptionally regulated by Tg-miR-60, the most abundant miRNA in a T. gondii type 1 strain [#1]\",\n      \"Conditional depletion impairs microneme secretion, invasion, replication, and egress [#2]\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_214470","name":"ULP1","product":"ubiquitin-like protease ULP1","uniprot_acc":"S8G4G1","chromosome":"TGME49_chrX","start_pos":6296827},{"strain":"GT1","gene_id":"TGGT1_214470","name":null,"product":"Ulp1 protease family, C-terminal catalytic domain-containing protein","uniprot_acc":null,"chromosome":"TGGT1_chrX","start_pos":6187338},{"strain":"RH88","gene_id":"TGRH88_040050","name":null,"product":"Ulp1 protease family, C-terminal catalytic domain-containing protein","uniprot_acc":null,"chromosome":"CM023091","start_pos":1233507},{"strain":"VEG","gene_id":"TGVEG_214470","name":null,"product":"Ulp1 protease family, C-terminal catalytic domain-containing protein","uniprot_acc":"V4Z705","chromosome":"TGVEG_chrX","start_pos":6225413}]}