{"gene":"TG_207820","gene_symbol":"MAPK2","run_date":"2026-09-10T21:09:19","timeline":{"discoveries":[{"year":2020,"finding":"MAPK2 (TgMAPK2) is essential for centrosome duplication and initiation of daughter cell budding in Toxoplasma. Auxin-inducible degron-mediated depletion of MAPK2 caused failure of centrosome duplication, arrest prior to mitosis (after initiation of but incomplete DNA replication), and parasite death, while Golgi, mitochondria, and apicoplasts continued to replicate — decoupling cell growth from cell division. MAPK2 was not observed at the centrosome, indicating it regulates centrosome duplication from a distal site.","method":"Auxin-inducible degron (AID) conditional knockdown, fluorescence microscopy, cell cycle analysis","journal":"mBio","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean conditional KO with specific cellular phenotype, multiple orthogonal readouts (centrosome duplication, DNA replication, organelle replication, budding), complementation-grade analysis in single focused study","pmids":["33173004"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2016,"finding":"Deletion of both TgMAPK1 and TgMAPK2 in type I parasites decreases acute virulence in mice, associated with low levels of IL-18, NLRP1/3, ASC, and caspase-1, and high levels of IL-10 and IFN-β transcripts, as well as increased STAT1 phosphorylation and decreased STAT3 phosphorylation, implicating both MAPKs in inflammasome activation during T. gondii infection.","method":"Gene deletion (knockout mutants), murine infection model, western blot, transcript analysis","journal":"Microbes and infection","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — clean KO with defined in vivo phenotype but double-knockout study makes it impossible to attribute phenotype specifically to MAPK2 alone; single lab, single study","pmids":["27475900"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"RH"}]},{"year":2011,"finding":"TgMAPK2 was molecularly cloned and characterized as a 678-amino-acid, 73.1 kDa protein with the 12 canonical MAPK subdomains and a TDY dual phosphorylation motif (distinct from mammalian ERK2's TEY motif). Recombinant TgMAPK2 was catalytically active in vitro and was not inhibited by the human ERK2 inhibitor FR180204. A partial TgMAPK2 lacking ATP-binding motifs was successfully regulated by the ligand-controlled ddFKBP destabilization domain system in T. gondii.","method":"Molecular cloning, sequence analysis, in vitro kinase activity assay, conditional expression (ddFKBP system)","journal":"Cell cycle","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro catalytic activity demonstrated with inhibitor specificity test; ddFKBP regulation confirmed in parasite; single lab, single study","pmids":["22030559"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2006,"finding":"TgMAPK2 was cloned and shown by phylogenetic analysis to be a member of a distinct and previously unknown protozoan MAPK subfamily (pzMAPK2), evolutionarily distant from ERK, JNK, and p38 families, and related to an ERK8-like family found across diverse eukaryotic kingdoms.","method":"Molecular cloning, phylogenetic analysis","journal":"Journal of molecular evolution","confidence":"Low","confidence_rationale":"Tier 4 / Weak — computational/phylogenetic analysis only; no functional experiment directly on TgMAPK2","pmids":["17160647"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2022,"finding":"Review consolidating that TgMAPK2 is essential for centrosome duplication and parasite replication, that apicomplexan MAPKs lack a canonical upstream kinase cascade, and that their regulation must occur by a distinct (non-canonical) mechanism. MAPK2 is noted as alveolata-specific with no metazoan ortholog.","method":"Review/synthesis (referencing experimental findings from primary studies)","journal":"PLoS pathogens","confidence":"Low","confidence_rationale":"Tier 4 / Weak — review paper; no new primary experiment on TgMAPK2 reported","pmids":["36227859"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"TgMAPK2 is an alveolata-specific, catalytically active serine/threonine kinase with a TDY dual-phosphorylation motif that is essential for Toxoplasma gondii replication: its loss prevents centrosome duplication and initiation of daughter cell budding while allowing continued growth of other organelles, placing MAPK2 at a distal regulatory node required specifically for the completion of centrosome duplication and the onset of parasite mitosis; it also contributes, together with TgMAPK1, to inflammasome activation and acute virulence in vivo."},"narrative":{"mechanistic_narrative":"TgMAPK2 is an alveolata-specific serine/threonine mitogen-activated protein kinase that governs the transition from cell growth to cell division in Toxoplasma gondii [PMID:33173004]. It is a catalytically active kinase bearing all 12 canonical MAPK subdomains and a distinctive TDY dual-phosphorylation motif, unlike the mammalian ERK2 TEY motif, and its activity is insensitive to the human ERK2 inhibitor FR180204 [PMID:22030559]. TgMAPK2 is essential for parasite replication: its depletion blocks centrosome duplication and the initiation of daughter cell budding, arresting parasites after incomplete DNA replication while Golgi, mitochondria, and apicoplasts continue to grow — decoupling organelle growth from cell division; because the kinase is not detected at the centrosome, it regulates centrosome duplication from a distal site [PMID:33173004]. Beyond its role in the cell cycle, TgMAPK2 together with TgMAPK1 contributes to inflammasome activation and acute virulence during murine infection [PMID:27475900]. How TgMAPK2 is activated remains uncharacterized in the available corpus, and no direct substrate has been identified.","teleology":[{"year":2006,"claim":"Establishing where TgMAPK2 sits in kinase evolution was the first step, showing it belongs to a distinct protozoan MAPK subfamily rather than the canonical ERK/JNK/p38 groups, and thus is unlikely to behave like a metazoan MAPK.","evidence":"Molecular cloning and phylogenetic analysis of TgMAPK2","pmids":["17160647"],"confidence":"Low","gaps":["Computational classification only, with no functional experiment on the kinase","Does not address whether the enzyme is catalytically active or essential"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"claim":"Whether TgMAPK2 is a bona fide active kinase was resolved by demonstrating recombinant catalytic activity and defining a non-canonical TDY dual-phosphorylation motif, distinguishing it biochemically from mammalian ERK2.","evidence":"Molecular cloning, sequence analysis, in vitro kinase assay with inhibitor specificity test, and ddFKBP conditional expression in T. gondii","pmids":["22030559"],"confidence":"Medium","gaps":["No physiological substrate identified","Upstream activating kinase or mechanism unknown","Single lab, single study"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2016,"claim":"Testing the in vivo importance of Toxoplasma MAPKs linked TgMAPK2, together with TgMAPK1, to acute virulence and inflammasome activation in the host.","evidence":"Double gene deletion of TgMAPK1 and TgMAPK2, murine infection, western blot and transcript analysis of inflammasome/cytokine markers","pmids":["27475900"],"confidence":"Medium","gaps":["Double-knockout design cannot attribute the phenotype to MAPK2 alone","Mechanistic link between kinase activity and inflammasome signaling not defined","Shown only in type I RH strain"],"attribution":[{"species":"Toxoplasma gondii","strain":"RH"}]},{"year":2020,"claim":"The core cellular function of TgMAPK2 was defined by showing it is essential for centrosome duplication and initiation of daughter cell budding, placing it at a distal regulatory node controlling entry into parasite mitosis.","evidence":"Auxin-inducible degron conditional depletion with fluorescence microscopy and cell cycle analysis of centrosome, DNA, organelle, and budding readouts","pmids":["33173004"],"confidence":"High","gaps":["Kinase substrates that drive centrosome duplication not identified","Mechanism by which a non-centrosomal kinase controls centrosome duplication unknown","Direct link between catalytic activity and the phenotype not established"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The activating input and downstream substrates of TgMAPK2 remain unknown: how a kinase lacking a canonical upstream MAPK cascade is regulated, and how it triggers centrosome duplication from a distal site, are unresolved.","evidence":"No direct experimental evidence in the timeline","pmids":[],"confidence":"Low","gaps":["No upstream regulator identified","No phosphorylation substrate identified","Non-canonical activation mechanism uncharacterized"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["TGMAPK1 (CO-DELETION CONTRIBUTES TO INFLAMMASOME ACTIVATION AND VIRULENCE)"],"other_free_text":["678-amino-acid, 73.1 kDa protein with 12 canonical MAPK subdomains and a non-canonical TDY dual-phosphorylation motif [#2]","Catalytically active in vitro and insensitive to the human ERK2 inhibitor FR180204 [#2]","Member of a distinct protozoan MAPK subfamily (pzMAPK2), ERK8-like, distant from ERK/JNK/p38 [#3]","Alveolata-specific with no metazoan ortholog; apicomplexan MAPKs lack a canonical upstream kinase cascade [#4]","Depletion decouples organelle growth (Golgi, mitochondria, apicoplast) from centrosome duplication and cell division [#0]","Not detected at the centrosome, indicating regulation from a distal site [#0]"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"24316259","id":"PMC_24316259","title":"Artemisinins: pharmacological actions beyond anti-malarial.","date":"2013","source":"Pharmacology & therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/24316259","citation_count":345,"is_preprint":false},{"pmid":"15778378","id":"PMC_15778378","title":"p38 MAPK autophosphorylation drives macrophage IL-12 production during intracellular infection.","date":"2005","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/15778378","citation_count":84,"is_preprint":false},{"pmid":"15361242","id":"PMC_15361242","title":"Manipulation of mitogen-activated protein kinase/nuclear factor-kappaB-signaling cascades during intracellular Toxoplasma gondii infection.","date":"2004","source":"Immunological 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Auxin-inducible degron-mediated depletion of MAPK2 caused failure of centrosome duplication, arrest prior to mitosis (after initiation of but incomplete DNA replication), and parasite death, while Golgi, mitochondria, and apicoplasts continued to replicate — decoupling cell growth from cell division. MAPK2 was not observed at the centrosome, indicating it regulates centrosome duplication from a distal site.\",\n      \"method\": \"Auxin-inducible degron (AID) conditional knockdown, fluorescence microscopy, cell cycle analysis\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean conditional KO with specific cellular phenotype, multiple orthogonal readouts (centrosome duplication, DNA replication, organelle replication, budding), complementation-grade analysis in single focused study\",\n      \"pmids\": [\"33173004\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Deletion of both TgMAPK1 and TgMAPK2 in type I parasites decreases acute virulence in mice, associated with low levels of IL-18, NLRP1/3, ASC, and caspase-1, and high levels of IL-10 and IFN-β transcripts, as well as increased STAT1 phosphorylation and decreased STAT3 phosphorylation, implicating both MAPKs in inflammasome activation during T. gondii infection.\",\n      \"method\": \"Gene deletion (knockout mutants), murine infection model, western blot, transcript analysis\",\n      \"journal\": \"Microbes and infection\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — clean KO with defined in vivo phenotype but double-knockout study makes it impossible to attribute phenotype specifically to MAPK2 alone; single lab, single study\",\n      \"pmids\": [\"27475900\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"TgMAPK2 was molecularly cloned and characterized as a 678-amino-acid, 73.1 kDa protein with the 12 canonical MAPK subdomains and a TDY dual phosphorylation motif (distinct from mammalian ERK2's TEY motif). Recombinant TgMAPK2 was catalytically active in vitro and was not inhibited by the human ERK2 inhibitor FR180204. A partial TgMAPK2 lacking ATP-binding motifs was successfully regulated by the ligand-controlled ddFKBP destabilization domain system in T. gondii.\",\n      \"method\": \"Molecular cloning, sequence analysis, in vitro kinase activity assay, conditional expression (ddFKBP system)\",\n      \"journal\": \"Cell cycle\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro catalytic activity demonstrated with inhibitor specificity test; ddFKBP regulation confirmed in parasite; single lab, single study\",\n      \"pmids\": [\"22030559\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"TgMAPK2 was cloned and shown by phylogenetic analysis to be a member of a distinct and previously unknown protozoan MAPK subfamily (pzMAPK2), evolutionarily distant from ERK, JNK, and p38 families, and related to an ERK8-like family found across diverse eukaryotic kingdoms.\",\n      \"method\": \"Molecular cloning, phylogenetic analysis\",\n      \"journal\": \"Journal of molecular evolution\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — computational/phylogenetic analysis only; no functional experiment directly on TgMAPK2\",\n      \"pmids\": [\"17160647\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Review consolidating that TgMAPK2 is essential for centrosome duplication and parasite replication, that apicomplexan MAPKs lack a canonical upstream kinase cascade, and that their regulation must occur by a distinct (non-canonical) mechanism. MAPK2 is noted as alveolata-specific with no metazoan ortholog.\",\n      \"method\": \"Review/synthesis (referencing experimental findings from primary studies)\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — review paper; no new primary experiment on TgMAPK2 reported\",\n      \"pmids\": [\"36227859\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"TgMAPK2 is an alveolata-specific, catalytically active serine/threonine kinase with a TDY dual-phosphorylation motif that is essential for Toxoplasma gondii replication: its loss prevents centrosome duplication and initiation of daughter cell budding while allowing continued growth of other organelles, placing MAPK2 at a distal regulatory node required specifically for the completion of centrosome duplication and the onset of parasite mitosis; it also contributes, together with TgMAPK1, to inflammasome activation and acute virulence in vivo.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TgMAPK2 is an alveolata-specific serine/threonine mitogen-activated protein kinase that governs the transition from cell growth to cell division in Toxoplasma gondii [#0]. It is a catalytically active kinase bearing all 12 canonical MAPK subdomains and a distinctive TDY dual-phosphorylation motif, unlike the mammalian ERK2 TEY motif, and its activity is insensitive to the human ERK2 inhibitor FR180204 [#2]. TgMAPK2 is essential for parasite replication: its depletion blocks centrosome duplication and the initiation of daughter cell budding, arresting parasites after incomplete DNA replication while Golgi, mitochondria, and apicoplasts continue to grow — decoupling organelle growth from cell division; because the kinase is not detected at the centrosome, it regulates centrosome duplication from a distal site [#0]. Beyond its role in the cell cycle, TgMAPK2 together with TgMAPK1 contributes to inflammasome activation and acute virulence during murine infection [#1]. How TgMAPK2 is activated remains uncharacterized in the available corpus, and no direct substrate has been identified.\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Establishing where TgMAPK2 sits in kinase evolution was the first step, showing it belongs to a distinct protozoan MAPK subfamily rather than the canonical ERK/JNK/p38 groups, and thus is unlikely to behave like a metazoan MAPK.\",\n      \"evidence\": \"Molecular cloning and phylogenetic analysis of TgMAPK2\",\n      \"pmids\": [\"17160647\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Computational classification only, with no functional experiment on the kinase\", \"Does not address whether the enzyme is catalytically active or essential\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Whether TgMAPK2 is a bona fide active kinase was resolved by demonstrating recombinant catalytic activity and defining a non-canonical TDY dual-phosphorylation motif, distinguishing it biochemically from mammalian ERK2.\",\n      \"evidence\": \"Molecular cloning, sequence analysis, in vitro kinase assay with inhibitor specificity test, and ddFKBP conditional expression in T. gondii\",\n      \"pmids\": [\"22030559\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No physiological substrate identified\", \"Upstream activating kinase or mechanism unknown\", \"Single lab, single study\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Testing the in vivo importance of Toxoplasma MAPKs linked TgMAPK2, together with TgMAPK1, to acute virulence and inflammasome activation in the host.\",\n      \"evidence\": \"Double gene deletion of TgMAPK1 and TgMAPK2, murine infection, western blot and transcript analysis of inflammasome/cytokine markers\",\n      \"pmids\": [\"27475900\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Double-knockout design cannot attribute the phenotype to MAPK2 alone\", \"Mechanistic link between kinase activity and inflammasome signaling not defined\", \"Shown only in type I RH strain\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"The core cellular function of TgMAPK2 was defined by showing it is essential for centrosome duplication and initiation of daughter cell budding, placing it at a distal regulatory node controlling entry into parasite mitosis.\",\n      \"evidence\": \"Auxin-inducible degron conditional depletion with fluorescence microscopy and cell cycle analysis of centrosome, DNA, organelle, and budding readouts\",\n      \"pmids\": [\"33173004\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase substrates that drive centrosome duplication not identified\", \"Mechanism by which a non-centrosomal kinase controls centrosome duplication unknown\", \"Direct link between catalytic activity and the phenotype not established\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The activating input and downstream substrates of TgMAPK2 remain unknown: how a kinase lacking a canonical upstream MAPK cascade is regulated, and how it triggers centrosome duplication from a distal site, are unresolved.\",\n      \"evidence\": \"No direct experimental evidence in the timeline\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No upstream regulator identified\", \"No phosphorylation substrate identified\", \"Non-canonical activation mechanism uncharacterized\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004707\", \"supporting_discovery_ids\": [2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0106310\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"GO:0051298\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0007049\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0002751\", \"supporting_discovery_ids\": [1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"TgMAPK1 (co-deletion contributes to inflammasome activation and virulence)\"],\n    \"other_free_text\": [\n      \"678-amino-acid, 73.1 kDa protein with 12 canonical MAPK subdomains and a non-canonical TDY dual-phosphorylation motif [#2]\",\n      \"Catalytically active in vitro and insensitive to the human ERK2 inhibitor FR180204 [#2]\",\n      \"Member of a distinct protozoan MAPK subfamily (pzMAPK2), ERK8-like, distant from ERK/JNK/p38 [#3]\",\n      \"Alveolata-specific with no metazoan ortholog; apicomplexan MAPKs lack a canonical upstream kinase cascade [#4]\",\n      \"Depletion decouples organelle growth (Golgi, mitochondria, apicoplast) from centrosome duplication and cell division [#0]\",\n      \"Not detected at the centrosome, indicating regulation from a distal site [#0]\"\n    ]\n  },\n  \"strain_conflicts\": []\n}\n```","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_207820","name":"MAPK2","product":"mitogen-activated protein kinase MAPK2","uniprot_acc":"A0A125YQE4","chromosome":"TGME49_chrIb","start_pos":311203},{"strain":"GT1","gene_id":"TGGT1_207820","name":null,"product":"putative cell-cycle-associated protein kinase MAPK","uniprot_acc":null,"chromosome":"TGGT1_chrIb","start_pos":328708},{"strain":"RH88","gene_id":"TGRH88_022820","name":null,"product":"putative cell-cycle-associated protein kinase MAPK","uniprot_acc":null,"chromosome":"CM023082","start_pos":1694891},{"strain":"VEG","gene_id":"TGVEG_207820","name":null,"product":"putative cell-cycle-associated protein kinase MAPK","uniprot_acc":"B6KP12","chromosome":"TGVEG_chrIb","start_pos":309956}]}