{"gene":"TG_226030","gene_symbol":"PKAC1","run_date":"2026-09-08T11:06:44","timeline":{"discoveries":[{"year":2017,"finding":"Inactive PKAc1 is maintained at the parasite pellicle by interacting with acylated PKAr (regulatory subunit); conditional knockdown of PKAr or overexpression of PKAc1 blocks parasite division, while down-regulation of PKAc1 or stabilisation of a dominant-negative PKAr isoform that cannot bind cAMP triggers premature egress dependent on host cell acidification.","method":"Conditional knockdown, overexpression, dominant-negative isoform stabilisation, phosphoproteome analysis","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal genetic approaches (knockdown, overexpression, dominant-negative) combined with phosphoproteomics, replicated across conditions in a single rigorous study","pmids":["29030485"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"PKAc1 inactivation changes the phosphorylation profile of a putative cGMP-phosphodiesterase, indicating crosstalk between cAMP and cGMP signalling; inhibition of PKG blocks egress induced by PKAc1 inactivation or environmental acidification, while a cGMP-phosphodiesterase inhibitor circumvents egress repression by PKAc1, placing PKAc1 upstream of cGMP metabolism in the egress pathway.","method":"Phosphoproteome analysis, pharmacological inhibition of PKG, phosphodiesterase inhibitor treatment, genetic epistasis","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — phosphoproteomics plus pharmacological epistasis with multiple orthogonal interventions establishing pathway order","pmids":["29030485"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2018,"finding":"PKAc1 is sequestered to the parasite periphery by dual acylation of PKA regulatory subunit 1 (PKAr1); genetic depletion of PKAc1 prevents rapid down-regulation of cytosolic Ca2+ levels shortly after invasion, and newly invaded parasites exit host cells in a PLP-1-dependent fashion, demonstrating that PKAc1 suppresses Ca2+ signalling upon host cell invasion.","method":"Genetic depletion (conditional knockdown), live cytosolic Ca2+ imaging, subcellular fractionation/localization, genetic epistasis with PLP-1","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic depletion combined with live Ca2+ imaging, localization, and epistasis with PLP-1 across multiple orthogonal methods in a single rigorous study","pmids":["30208022"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2018,"finding":"Loss of PKAc1 sensitises parasites to cGMP-induced Ca2+ signalling, demonstrating a functional link between cAMP/PKAc1 and cGMP/Ca2+ signalling modalities.","method":"Genetic depletion of PKAc1, pharmacological cGMP elevation, cytosolic Ca2+ imaging","journal":"PLoS biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — single lab, genetic depletion plus pharmacological and imaging methods, no independent replication","pmids":["30208022"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2022,"finding":"cAMP signalling through TgPKAc1 inhibits Toxoplasma motility; TgPDE2, a cAMP-specific phosphodiesterase localised to the ER/cytomembranes, regulates cAMP levels and is functionally linked to PKAc1-mediated suppression of motility.","method":"Knockdown screen, biochemical substrate specificity assay of purified TgPDE2, interactome studies, motility/growth assays","journal":"mSphere","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — PKAc1's role as inhibitor of motility established by prior work and contextualised here; TgPDE2's cAMP specificity established by in vitro biochemical assay in single study","pmids":["35107337"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2025,"finding":"Shortly after invasion, PKAc1 is activated by cAMP produced by adenylate cyclases and suppresses the PKG/CDPK pathway; PKAc1 further activates phosphodiesterase 2 (PDE2), which selectively consumes cAMP to form a negative feedback loop causing transient PKAc1 activation. Perturbation experiments place PKAc1 action between guanylate cyclase and calcium release in the signalling hierarchy.","method":"Genetic perturbation of cyclic nucleotide pathways, pharmacological manipulation of cGMP vs Ca2+, epistasis analysis","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic and pharmacological epistasis in single lab study establishing pathway order; no independent replication yet","pmids":["39903669"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"Toxoplasma gondii PKAc1 is held inactive at the parasite pellicle via interaction with dually acylated PKAr1; upon host cell invasion, adenylate cyclase-produced cAMP activates PKAc1, which suppresses cytosolic Ca2+ signalling and the PKG/CDPK motility pathway to enforce intracellular replication, while also activating PDE2 to degrade cAMP in a transient negative feedback loop, and modulates a cGMP-phosphodiesterase to coordinate crosstalk between cAMP and cGMP signalling that governs the switch between intracellular growth and host cell egress."},"narrative":{"mechanistic_narrative":"Toxoplasma gondii PKAc1 is the catalytic subunit of a cAMP-dependent protein kinase that acts as a master switch enforcing the intracellular replicative state and repressing premature host cell egress [PMID:29030485]. The kinase is held inactive at the parasite pellicle through interaction with the dually acylated regulatory subunit PKAr1, and conditional depletion of PKAc1 or expression of a cAMP-insensitive dominant-negative PKAr triggers premature, acidification-dependent egress [PMID:29030485, PMID:30208022]. Shortly after invasion, adenylate-cyclase-derived cAMP activates PKAc1, which suppresses cytosolic Ca2+ signalling and the PKG/CDPK motility pathway to lock the parasite into replication, with loss of PKAc1 sensitising parasites to cGMP-induced Ca2+ release [PMID:30208022, PMID:39903669]. Epistasis places PKAc1 action between guanylate cyclase and calcium release and upstream of cGMP metabolism, consistent with PKAc1 modulating a cGMP-phosphodiesterase to coordinate cAMP/cGMP crosstalk governing the growth-versus-egress switch [PMID:29030485, PMID:39903669]. PKAc1 additionally activates the cAMP-specific phosphodiesterase PDE2 to consume cAMP, generating a negative feedback loop that renders PKAc1 activation transient and inhibits motility [PMID:35107337, PMID:39903669].","teleology":[{"year":2017,"claim":"Established that PKAc1 is a pellicle-tethered kinase whose activity level dictates the choice between intracellular division and premature egress, defining it as a checkpoint controller of the lytic cycle.","evidence":"Conditional knockdown, overexpression, and dominant-negative PKAr stabilisation with phosphoproteomics in T. gondii","pmids":["29030485"],"confidence":"High","gaps":["Direct kinase substrates driving the egress block not identified","Molecular basis of pellicle tethering only partly resolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"Positioned PKAc1 upstream of cGMP metabolism and PKG in the egress pathway, revealing cAMP/cGMP crosstalk through a putative cGMP-phosphodiesterase.","evidence":"Phosphoproteomics plus pharmacological PKG inhibition, phosphodiesterase inhibitor treatment, and genetic epistasis in T. gondii","pmids":["29030485"],"confidence":"High","gaps":["Identity of the cGMP-phosphodiesterase not confirmed","Direct phosphorylation of the phosphodiesterase by PKAc1 not demonstrated"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2018,"claim":"Showed PKAc1 actively suppresses cytosolic Ca2+ immediately after invasion, mechanistically linking loss of the kinase to PLP-1-dependent premature exit.","evidence":"Conditional depletion, live cytosolic Ca2+ imaging, localization, and PLP-1 epistasis in T. gondii","pmids":["30208022"],"confidence":"High","gaps":["Effectors linking PKAc1 to Ca2+ suppression unknown","How PKAr1 acylation is regulated not addressed"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2018,"claim":"Demonstrated that PKAc1 loss sensitises parasites to cGMP-induced Ca2+ signalling, functionally coupling the cAMP and cGMP/Ca2+ arms.","evidence":"Genetic depletion of PKAc1 with pharmacological cGMP elevation and Ca2+ imaging in T. gondii","pmids":["30208022"],"confidence":"Medium","gaps":["Single lab, no independent replication","Molecular node of convergence between cGMP and Ca2+ undefined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2022,"claim":"Connected PKAc1-mediated motility suppression to the cAMP-specific phosphodiesterase TgPDE2, defining a component that shapes the cAMP pool PKAc1 responds to.","evidence":"Knockdown screen, in vitro substrate specificity of purified TgPDE2, interactome and motility/growth assays in T. gondii","pmids":["35107337"],"confidence":"Medium","gaps":["Direct regulatory relationship between PKAc1 and PDE2 not established in this study","Single lab, no independent replication"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2025,"claim":"Resolved the temporal logic: cAMP transiently activates PKAc1, which suppresses PKG/CDPK and activates PDE2 in a negative feedback loop, placing PKAc1 between guanylate cyclase and calcium release.","evidence":"Genetic and pharmacological perturbation of cyclic nucleotide pathways with epistasis analysis in T. gondii","pmids":["39903669"],"confidence":"Medium","gaps":["Direct PKAc1 substrates in the PKG/CDPK and PDE2 branches not identified","Single lab, no independent replication"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The direct phosphorylation substrates through which PKAc1 suppresses Ca2+ and the PKG/CDPK pathway, and the molecular mechanism coupling it to cGMP/cAMP phosphodiesterases, remain uncharacterized.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No direct kinase substrate identified","No structural model of the PKAc1/PKAr1 complex in the corpus","Mechanism of adenylate cyclase-PKAc1 coupling undefined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["PKAc1-PKAr1 holoenzyme (catalytic subunit bound to dually acylated regulatory subunit 1)"],"partners":["PKAR1 (REGULATORY SUBUNIT)","TGPDE2 (CAMP-SPECIFIC PHOSPHODIESTERASE)","PKG (FUNCTIONAL/EPISTATIC LINK)","PUTATIVE CGMP-PHOSPHODIESTERASE"],"other_free_text":["PKAc1 suppresses PLP-1-dependent premature egress following invasion","PKAc1 activation is transient owing to PDE2-mediated negative feedback on cAMP","Epistasis places PKAc1 between guanylate cyclase and calcium release in the egress signalling hierarchy"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"29030485","id":"PMC_29030485","title":"Crosstalk between PKA and PKG controls pH-dependent host cell egress of Toxoplasma gondii.","date":"2017","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/29030485","citation_count":83,"is_preprint":false},{"pmid":"27247232","id":"PMC_27247232","title":"Toxoplasma gondii Cyclic AMP-Dependent Protein Kinase Subunit 3 Is Involved in the Switch from Tachyzoite to Bradyzoite Development.","date":"2016","source":"mBio","url":"https://pubmed.ncbi.nlm.nih.gov/27247232","citation_count":58,"is_preprint":false},{"pmid":"30208022","id":"PMC_30208022","title":"Protein kinase A negatively regulates Ca2+ signalling in Toxoplasma gondii.","date":"2018","source":"PLoS biology","url":"https://pubmed.ncbi.nlm.nih.gov/30208022","citation_count":55,"is_preprint":false},{"pmid":"35107337","id":"PMC_35107337","title":"Functional Analysis of the Expanded Phosphodiesterase Gene Family in Toxoplasma gondii Tachyzoites.","date":"2022","source":"mSphere","url":"https://pubmed.ncbi.nlm.nih.gov/35107337","citation_count":19,"is_preprint":false},{"pmid":"39903669","id":"PMC_39903669","title":"Phospho-relay feedback loops control egress vs. intracellular development in Toxoplasma gondii.","date":"2025","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/39903669","citation_count":3,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":5410,"output_tokens":1737,"usd":0.021143,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":7011,"output_tokens":3119,"usd":0.056515,"stage2_stop_reason":"end_turn"},"total_usd":0.077658,"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\": 2017,\n      \"finding\": \"Inactive PKAc1 is maintained at the parasite pellicle by interacting with acylated PKAr (regulatory subunit); conditional knockdown of PKAr or overexpression of PKAc1 blocks parasite division, while down-regulation of PKAc1 or stabilisation of a dominant-negative PKAr isoform that cannot bind cAMP triggers premature egress dependent on host cell acidification.\",\n      \"method\": \"Conditional knockdown, overexpression, dominant-negative isoform stabilisation, phosphoproteome analysis\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal genetic approaches (knockdown, overexpression, dominant-negative) combined with phosphoproteomics, replicated across conditions in a single rigorous study\",\n      \"pmids\": [\"29030485\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"PKAc1 inactivation changes the phosphorylation profile of a putative cGMP-phosphodiesterase, indicating crosstalk between cAMP and cGMP signalling; inhibition of PKG blocks egress induced by PKAc1 inactivation or environmental acidification, while a cGMP-phosphodiesterase inhibitor circumvents egress repression by PKAc1, placing PKAc1 upstream of cGMP metabolism in the egress pathway.\",\n      \"method\": \"Phosphoproteome analysis, pharmacological inhibition of PKG, phosphodiesterase inhibitor treatment, genetic epistasis\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — phosphoproteomics plus pharmacological epistasis with multiple orthogonal interventions establishing pathway order\",\n      \"pmids\": [\"29030485\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"PKAc1 is sequestered to the parasite periphery by dual acylation of PKA regulatory subunit 1 (PKAr1); genetic depletion of PKAc1 prevents rapid down-regulation of cytosolic Ca2+ levels shortly after invasion, and newly invaded parasites exit host cells in a PLP-1-dependent fashion, demonstrating that PKAc1 suppresses Ca2+ signalling upon host cell invasion.\",\n      \"method\": \"Genetic depletion (conditional knockdown), live cytosolic Ca2+ imaging, subcellular fractionation/localization, genetic epistasis with PLP-1\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic depletion combined with live Ca2+ imaging, localization, and epistasis with PLP-1 across multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"30208022\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Loss of PKAc1 sensitises parasites to cGMP-induced Ca2+ signalling, demonstrating a functional link between cAMP/PKAc1 and cGMP/Ca2+ signalling modalities.\",\n      \"method\": \"Genetic depletion of PKAc1, pharmacological cGMP elevation, cytosolic Ca2+ imaging\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — single lab, genetic depletion plus pharmacological and imaging methods, no independent replication\",\n      \"pmids\": [\"30208022\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"cAMP signalling through TgPKAc1 inhibits Toxoplasma motility; TgPDE2, a cAMP-specific phosphodiesterase localised to the ER/cytomembranes, regulates cAMP levels and is functionally linked to PKAc1-mediated suppression of motility.\",\n      \"method\": \"Knockdown screen, biochemical substrate specificity assay of purified TgPDE2, interactome studies, motility/growth assays\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — PKAc1's role as inhibitor of motility established by prior work and contextualised here; TgPDE2's cAMP specificity established by in vitro biochemical assay in single study\",\n      \"pmids\": [\"35107337\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Shortly after invasion, PKAc1 is activated by cAMP produced by adenylate cyclases and suppresses the PKG/CDPK pathway; PKAc1 further activates phosphodiesterase 2 (PDE2), which selectively consumes cAMP to form a negative feedback loop causing transient PKAc1 activation. Perturbation experiments place PKAc1 action between guanylate cyclase and calcium release in the signalling hierarchy.\",\n      \"method\": \"Genetic perturbation of cyclic nucleotide pathways, pharmacological manipulation of cGMP vs Ca2+, epistasis analysis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic and pharmacological epistasis in single lab study establishing pathway order; no independent replication yet\",\n      \"pmids\": [\"39903669\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"Toxoplasma gondii PKAc1 is held inactive at the parasite pellicle via interaction with dually acylated PKAr1; upon host cell invasion, adenylate cyclase-produced cAMP activates PKAc1, which suppresses cytosolic Ca2+ signalling and the PKG/CDPK motility pathway to enforce intracellular replication, while also activating PDE2 to degrade cAMP in a transient negative feedback loop, and modulates a cGMP-phosphodiesterase to coordinate crosstalk between cAMP and cGMP signalling that governs the switch between intracellular growth and host cell egress.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"Toxoplasma gondii PKAc1 is the catalytic subunit of a cAMP-dependent protein kinase that acts as a master switch enforcing the intracellular replicative state and repressing premature host cell egress [#0]. The kinase is held inactive at the parasite pellicle through interaction with the dually acylated regulatory subunit PKAr1, and conditional depletion of PKAc1 or expression of a cAMP-insensitive dominant-negative PKAr triggers premature, acidification-dependent egress [#0, #2]. Shortly after invasion, adenylate-cyclase-derived cAMP activates PKAc1, which suppresses cytosolic Ca2+ signalling and the PKG/CDPK motility pathway to lock the parasite into replication, with loss of PKAc1 sensitising parasites to cGMP-induced Ca2+ release [#2, #3, #5]. Epistasis places PKAc1 action between guanylate cyclase and calcium release and upstream of cGMP metabolism, consistent with PKAc1 modulating a cGMP-phosphodiesterase to coordinate cAMP/cGMP crosstalk governing the growth-versus-egress switch [#1, #5]. PKAc1 additionally activates the cAMP-specific phosphodiesterase PDE2 to consume cAMP, generating a negative feedback loop that renders PKAc1 activation transient and inhibits motility [#4, #5].\"\n  ,\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Established that PKAc1 is a pellicle-tethered kinase whose activity level dictates the choice between intracellular division and premature egress, defining it as a checkpoint controller of the lytic cycle.\",\n      \"evidence\": \"Conditional knockdown, overexpression, and dominant-negative PKAr stabilisation with phosphoproteomics in T. gondii\",\n      \"pmids\": [\"29030485\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct kinase substrates driving the egress block not identified\", \"Molecular basis of pellicle tethering only partly resolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Positioned PKAc1 upstream of cGMP metabolism and PKG in the egress pathway, revealing cAMP/cGMP crosstalk through a putative cGMP-phosphodiesterase.\",\n      \"evidence\": \"Phosphoproteomics plus pharmacological PKG inhibition, phosphodiesterase inhibitor treatment, and genetic epistasis in T. gondii\",\n      \"pmids\": [\"29030485\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the cGMP-phosphodiesterase not confirmed\", \"Direct phosphorylation of the phosphodiesterase by PKAc1 not demonstrated\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Showed PKAc1 actively suppresses cytosolic Ca2+ immediately after invasion, mechanistically linking loss of the kinase to PLP-1-dependent premature exit.\",\n      \"evidence\": \"Conditional depletion, live cytosolic Ca2+ imaging, localization, and PLP-1 epistasis in T. gondii\",\n      \"pmids\": [\"30208022\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Effectors linking PKAc1 to Ca2+ suppression unknown\", \"How PKAr1 acylation is regulated not addressed\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Demonstrated that PKAc1 loss sensitises parasites to cGMP-induced Ca2+ signalling, functionally coupling the cAMP and cGMP/Ca2+ arms.\",\n      \"evidence\": \"Genetic depletion of PKAc1 with pharmacological cGMP elevation and Ca2+ imaging in T. gondii\",\n      \"pmids\": [\"30208022\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab, no independent replication\", \"Molecular node of convergence between cGMP and Ca2+ undefined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Connected PKAc1-mediated motility suppression to the cAMP-specific phosphodiesterase TgPDE2, defining a component that shapes the cAMP pool PKAc1 responds to.\",\n      \"evidence\": \"Knockdown screen, in vitro substrate specificity of purified TgPDE2, interactome and motility/growth assays in T. gondii\",\n      \"pmids\": [\"35107337\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct regulatory relationship between PKAc1 and PDE2 not established in this study\", \"Single lab, no independent replication\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved the temporal logic: cAMP transiently activates PKAc1, which suppresses PKG/CDPK and activates PDE2 in a negative feedback loop, placing PKAc1 between guanylate cyclase and calcium release.\",\n      \"evidence\": \"Genetic and pharmacological perturbation of cyclic nucleotide pathways with epistasis analysis in T. gondii\",\n      \"pmids\": [\"39903669\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct PKAc1 substrates in the PKG/CDPK and PDE2 branches not identified\", \"Single lab, no independent replication\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The direct phosphorylation substrates through which PKAc1 suppresses Ca2+ and the PKG/CDPK pathway, and the molecular mechanism coupling it to cGMP/cAMP phosphodiesterases, remain uncharacterized.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct kinase substrate identified\", \"No structural model of the PKAc1/PKAr1 complex in the corpus\", \"Mechanism of adenylate cyclase-PKAc1 coupling undefined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004672\", \"supporting_discovery_ids\": [0, 5], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0004691\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0030552\", \"supporting_discovery_ids\": [0, 5], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0071944\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0007189\", \"supporting_discovery_ids\": [0, 5], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0019933\", \"supporting_discovery_ids\": [1, 3, 5], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0051209\", \"supporting_discovery_ids\": [2, 3], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [\n      \"PKAc1-PKAr1 holoenzyme (catalytic subunit bound to dually acylated regulatory subunit 1)\"\n    ],\n    \"partners\": [\n      \"PKAr1 (regulatory subunit)\",\n      \"TgPDE2 (cAMP-specific phosphodiesterase)\",\n      \"PKG (functional/epistatic link)\",\n      \"putative cGMP-phosphodiesterase\"\n    ],\n    \"other_free_text\": [\n      \"PKAc1 suppresses PLP-1-dependent premature egress following invasion\",\n      \"PKAc1 activation is transient owing to PDE2-mediated negative feedback on cAMP\",\n      \"Epistasis places PKAc1 between guanylate cyclase and calcium release in the egress signalling hierarchy\"\n    ]\n  },\n  \"strain_conflicts\": []\n}\n```","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_226030","name":"PKAC1","product":"cAMP-dependent protein kinase subunit PKAc1","uniprot_acc":"A0A125YVN4","chromosome":"TGME49_chrX","start_pos":1854247},{"strain":"GT1","gene_id":"TGGT1_226030","name":null,"product":"AGC kinase","uniprot_acc":null,"chromosome":"TGGT1_chrX","start_pos":1762934},{"strain":"RH88","gene_id":"TGRH88_045700","name":null,"product":"AGC kinase","uniprot_acc":null,"chromosome":"CM023091","start_pos":5714203},{"strain":"VEG","gene_id":"TGVEG_226030","name":null,"product":"AGC kinase","uniprot_acc":"B9PMK9","chromosome":"TGVEG_chrX","start_pos":1754685}]}