{"gene":"PF3D7_1114700","run_date":"2026-09-08T12:51:28","timeline":{"discoveries":[{"year":2011,"finding":"Phosphorylation of PfCLK3 (CLK3/PF3D7_1114700) at tyrosine Y526 in the activation loop is essential for full kinase activity, as demonstrated by global phospho-proteomic analysis combined with functional validation.","method":"Global phospho-proteomic analysis; functional validation of phosphorylation site (Y526) as essential for kinase activity","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — phospho-proteomics identified the site and functional validation was performed, single lab with two orthogonal approaches","pmids":["22127061"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2014,"finding":"CLK3 (one of four PfCLKs) phosphorylates SR proteins (PfSRSF12, PfSFRS4, PfSF-1) via their Arginine/Serine-rich (RS) domains in vitro; a PfSF-1 peptide lacking the RS-rich domain was not phosphorylated. CLK3 localizes to both the nucleus and cytoplasm in asexual blood stages and gametocytes.","method":"In vitro kinase assay with recombinant SR protein substrates; immunofluorescence localization","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct in vitro kinase assay with domain-deletion control, subcellular localization shown, but single lab","pmids":["25188378"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2019,"finding":"CLK3 (PF3D7_1114700) is essential for parasite survival at multiple life stages (asexual blood stage, liver stage, gametocyte development). Selective inhibition of CLK3 causes down-regulation of more than 400 essential parasite genes, consistent with a role in RNA splicing. Chemogenetic validation confirmed CLK3 as the target of the selective inhibitor TCMDC-135051.","method":"Selective chemical inhibition combined with chemogenetics (bumped kinase inhibitor / analog-sensitive allele strategy); transcriptomic analysis; multi-stage parasite assays including P. berghei and P. knowlesi","journal":"Science (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 2 / Strong — chemogenetic target validation plus transcriptomics across multiple species and life stages, multiple orthogonal methods in a single rigorous study","pmids":["31467193"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium berghei","strain":""},{"species":"Plasmodium knowlesi","strain":""}]},{"year":2022,"finding":"The crystal/structural analysis of PfCLK3 (CLK3/PF3D7_1114700) identified key residues within the kinase catalytic site; the inhibitor altiratinib targets PfCLK3 and causes global disruption of RNA splicing (primarily intron retention) in P. falciparum. Structural features critical for binding of TCMDC-135051 to PfCLK3 were also elucidated.","method":"Genetic target deconvolution; structural analysis of kinase catalytic site; RNA sequencing to assess splicing disruption; resistance-conferring mutations identified","journal":"Science translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic deconvolution plus RNA-seq for mechanism, structural analysis, single study","pmids":["35921477"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2024,"finding":"The co-crystal structure of PfCLK3 (CLK3/PF3D7_1114700) with reversible inhibitor TCMDC-135051 was solved, revealing a unique cysteine residue (Cys368) poorly conserved in the human kinome. Covalent inhibitors targeting Cys368 showed nanomolar potency and covalent inhibition in both recombinant protein assays and P. falciparum parasites, with efficacy persisting after 6-hour washout.","method":"Co-crystal structure determination; covalent inhibitor design and testing; recombinant protein kinase assays; parasite growth assays with washout","journal":"Journal of medicinal chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure plus biochemical validation with covalent inhibitors and mutagenesis-informed design, single lab but multiple orthogonal methods","pmids":["39441986"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2026,"finding":"Selective inhibition of PfCLK3 (CLK3/PF3D7_1114700) extensively disrupts RNA splicing: 2,039 splice junctions across 1,125 genes were mis-spliced in treated wild-type parasites compared to controls. Mis-spliced transcripts are involved in essential parasite processes across multiple life cycle stages, establishing PfCLK3 as a key regulator of spliceosome activity.","method":"RNA sequencing (RNAseq) of parasites treated with selective PfCLK3 inhibitor versus controls; wild-type vs inhibitor-resistant parasite comparison","journal":"Antimicrobial agents and chemotherapy","confidence":"High","confidence_rationale":"Tier 2 / Strong — selective inhibitor with resistance controls, transcriptome-wide RNA-seq, multiple orthogonal validations, direct mechanistic link established","pmids":["42363832"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2026,"finding":"Chemical proteomics (chemical pulldown and thermal proteome profiling) demonstrated that the azaindole compound TCMDC-135051 is a selective inhibitor of PfCLK3 (CLK3/PF3D7_1114700) among the P. falciparum kinome.","method":"Chemical pulldown; thermal proteome profiling (two orthogonal chemical proteomics approaches)","journal":"ACS infectious diseases","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — two orthogonal chemical proteomics methods confirm selectivity for PfCLK3, single study","pmids":["42345078"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2026,"finding":"Structure-based drug design targeting the catalytic lysine residue (Lys394) of PfCLK3 (CLK3/PF3D7_1114700) with benzaldehyde-based warheads resulted in covalent engagement of Lys394 confirmed by protein mass spectrometry, establishing Lys394 as a covalent targeting site distinct from Cys368.","method":"Structure-based drug design; protein mass spectrometry confirmation of covalent Lys394 engagement; recombinant protein kinase assays; parasite growth assays","journal":"RSC medicinal chemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — direct mass spectrometry confirmation of covalent adduct, structure-informed design, single lab","pmids":["40521344"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"PfCLK3 (PF3D7_1114700) is an essential, nuclear and cytoplasmic cyclin-dependent-like kinase whose activation requires phosphorylation at Y526 in its activation loop; it phosphorylates SR proteins via their RS-rich domains and acts as a key regulator of spliceosome activity — selective inhibition causes widespread intron retention and mis-splicing of over 1,000 genes essential across blood, liver, and sexual parasite life stages, and the kinase's catalytic site harbors a unique Cys368 (and catalytic Lys394) that can be covalently targeted by inhibitors with nanomolar parasiticidal potency."},"narrative":{"mechanistic_narrative":"CLK3 (PF3D7_1114700) is an essential cyclin-dependent-like protein kinase of Plasmodium falciparum that functions as a key regulator of spliceosome activity across the parasite life cycle [PMID:31467193, PMID:42363832]. As a kinase, its full catalytic activity requires phosphorylation at tyrosine Y526 in its activation loop [PMID:22127061], and it phosphorylates SR (serine/arginine-rich) proteins — PfSRSF12, PfSFRS4, and PfSF-1 — specifically through their Arg/Ser-rich (RS) domains, since an RS-domain-deleted PfSF-1 peptide is not a substrate [PMID:25188378]. Consistent with this role in pre-mRNA splicing regulation, CLK3 localizes to both the nucleus and cytoplasm in asexual blood stages and gametocytes [PMID:25188378]. CLK3 is essential for survival at multiple life stages — asexual blood stage, liver stage, and gametocyte development — and its selective inhibition causes transcriptome-wide mis-splicing, with intron retention and over 2,000 aberrant splice junctions across more than 1,000 genes involved in essential processes [PMID:31467193, PMID:35921477, PMID:42363832]. The kinase has been chemogenetically validated as the target of the selective inhibitor TCMDC-135051 [PMID:31467193, PMID:42345078], and structural analysis has defined its catalytic site, including a Cys368 poorly conserved in the human kinome and a catalytic Lys394, both of which can be covalently engaged by inhibitors with nanomolar parasiticidal potency [PMID:35921477, PMID:39441986, PMID:40521344].","teleology":[{"year":2011,"claim":"Establishing how CLK3 catalytic activity is switched on, phospho-proteomics identified an activation-loop tyrosine whose phosphorylation is essential for full kinase activity.","evidence":"Global phospho-proteomic analysis with functional validation of the Y526 site","pmids":["22127061"],"confidence":"Medium","gaps":["The upstream kinase responsible for Y526 phosphorylation is not identified","Whether Y526 phosphorylation is regulated across life stages is unknown"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2014,"claim":"To define what CLK3 acts on, in vitro kinase assays showed it phosphorylates SR proteins through their RS-rich domains, linking the kinase to the splicing machinery, and localization placed it in both nucleus and cytoplasm.","evidence":"In vitro kinase assays with recombinant SR protein substrates plus an RS-domain-deletion control; immunofluorescence localization in asexual and gametocyte stages","pmids":["25188378"],"confidence":"Medium","gaps":["Substrate phosphorylation shown in vitro but not confirmed in vivo","Cellular consequence of SR protein phosphorylation not yet demonstrated"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2019,"claim":"To establish essentiality and therapeutic relevance, chemogenetic target validation confirmed CLK3 as the target of TCMDC-135051 and showed its inhibition kills parasites at multiple life stages while down-regulating hundreds of essential genes, consistent with a splicing role.","evidence":"Selective chemical inhibition with analog-sensitive/chemogenetic validation, transcriptomics, and multi-stage assays including P. berghei and P. knowlesi","pmids":["31467193"],"confidence":"High","gaps":["Transcriptional down-regulation was measured but direct splicing defects were not yet resolved here","Mechanistic connection between kinase activity and specific splicing events not established at this stage"],"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium berghei","strain":""},{"species":"Plasmodium knowlesi","strain":""}]},{"year":2022,"claim":"To connect kinase inhibition to a defined molecular outcome, structural analysis mapped the catalytic site and RNA-seq showed that inhibition (by altiratinib and TCMDC-135051) causes global splicing disruption dominated by intron retention.","evidence":"Genetic target deconvolution, structural analysis of the catalytic site, RNA sequencing, and resistance-mutation mapping","pmids":["35921477"],"confidence":"Medium","gaps":["Which SR-protein phosphorylation events drive the observed intron retention is not directly resolved","No full-length co-crystal structure reported in this study"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2024,"claim":"To enable durable covalent inhibition, a co-crystal structure with TCMDC-135051 revealed a Cys368 poorly conserved in the human kinome, and covalent inhibitors targeting it showed nanomolar potency with washout-resistant efficacy.","evidence":"Co-crystal structure determination, covalent inhibitor design, recombinant kinase assays, and parasite growth assays with 6-hour washout","pmids":["39441986"],"confidence":"High","gaps":["In vivo efficacy and selectivity of Cys368-targeting covalent inhibitors not yet established","Resistance liability of covalent engagement not characterized"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2026,"claim":"To resolve the scale of the splicing defect and confirm inhibitor selectivity, transcriptome-wide RNA-seq quantified mis-splicing across >1,000 genes, and orthogonal chemical proteomics confirmed TCMDC-135051 as a selective CLK3 inhibitor within the parasite kinome.","evidence":"RNA-seq of inhibitor-treated wild-type versus resistant parasites (2,039 mis-spliced junctions across 1,125 genes); chemical pulldown and thermal proteome profiling for selectivity","pmids":["42363832","42345078"],"confidence":"High","gaps":["Direct catalytic mechanism linking CLK3 activity to each mis-spliced junction not resolved","Whether mis-splicing is a direct kinase effect or a downstream consequence not fully separated"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2026,"claim":"To expand the covalent targeting strategy, structure-based design engaged the catalytic Lys394 with benzaldehyde warheads, establishing a covalent site distinct from Cys368.","evidence":"Structure-based drug design with protein mass spectrometry confirmation of Lys394 adduct, recombinant kinase assays, and parasite growth assays","pmids":["40521344"],"confidence":"Medium","gaps":["Comparative advantage of Lys394 versus Cys368 targeting not established","In vivo activity of Lys394-covalent compounds not reported"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"How CLK3-mediated SR protein phosphorylation is mechanistically coupled to specific spliceosome assembly and intron-retention events, and how CLK3 activity is regulated across the life cycle, remains open.","evidence":"","pmids":[],"confidence":"Medium","gaps":["In vivo substrate phosphorylation map not established","Upstream regulators of Y526 phosphorylation unknown","Direct link between individual SR-protein phosphosites and specific splicing outcomes not demonstrated"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["PFSRSF12 (SR PROTEIN SUBSTRATE)","PFSFRS4 (SR PROTEIN SUBSTRATE)","PFSF-1 (SR PROTEIN SUBSTRATE)"],"other_free_text":["Activation requires phosphorylation at activation-loop tyrosine Y526 [#0]","Phosphorylates SR proteins specifically via their RS-rich domains [#1]","Essential across asexual blood stage, liver stage, and gametocyte development [#2]","Chemogenetically validated target of the selective inhibitor TCMDC-135051 [#2, #6]","Catalytic site harbors Cys368 (poorly conserved in the human kinome) and catalytic Lys394, both covalently targetable by nanomolar inhibitors [#4, #7]","Selective inhibition causes transcriptome-wide mis-splicing dominated by intron retention (2,039 junctions across 1,125 genes) [#3, #5]"]}},"prefetch_data":{},"corpus_meta":[{"pmid":"15479470","id":"PMC_15479470","title":"Protein kinases of the human malaria parasite Plasmodium falciparum: the kinome of a divergent eukaryote.","date":"2004","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/15479470","citation_count":421,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["curated_ref"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"22127061","id":"PMC_22127061","title":"Global kinomic and phospho-proteomic analyses of the human malaria parasite Plasmodium falciparum.","date":"2011","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/22127061","citation_count":288,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"31467193","id":"PMC_31467193","title":"Validation of the protein kinase PfCLK3 as a multistage cross-species malarial drug target.","date":"2019","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/31467193","citation_count":57,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"32787140","id":"PMC_32787140","title":"Development of Potent PfCLK3 Inhibitors Based on TCMDC-135051 as a New Class of Antimalarials.","date":"2020","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/32787140","citation_count":32,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"25188378","id":"PMC_25188378","title":"Inhibition of the SR protein-phosphorylating CLK kinases of Plasmodium falciparum impairs blood stage replication and malaria transmission.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25188378","citation_count":32,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["curated_ref"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"35921477","id":"PMC_35921477","title":"Altiratinib blocks Toxoplasma gondii and Plasmodium falciparum development by selectively targeting a spliceosome kinase.","date":"2022","source":"Science translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35921477","citation_count":18,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CLK3","PfCLK3"],"competing_organism_flag":true,"competing_organism_match":"Toxoplasma","competing_organism_only":false},{"pmid":"39441986","id":"PMC_39441986","title":"Targeting PfCLK3 with Covalent Inhibitors: A Novel Strategy for Malaria Treatment.","date":"2024","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/39441986","citation_count":7,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"32946682","id":"PMC_32946682","title":"Temperature does matter-an additional dimension in kinase inhibitor development.","date":"2020","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/32946682","citation_count":4,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"40521344","id":"PMC_40521344","title":"Lysine targeting covalent inhibitors of malarial kinase PfCLK3.","date":"2025","source":"RSC medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/40521344","citation_count":3,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CLK3","PfCLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"33612795","id":"PMC_33612795","title":"Plasmodium falciparum protein kinase as a potential therapeutic target for antimalarial drugs development.","date":"2020","source":"Tropical biomedicine","url":"https://pubmed.ncbi.nlm.nih.gov/33612795","citation_count":2,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"39370241","id":"PMC_39370241","title":"Another decade of antimalarial drug discovery: New targets, tools and molecules.","date":"2024","source":"Progress in medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/39370241","citation_count":1,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"41618901","id":"PMC_41618901","title":"Shaping Antimalarials: A Geometry-First Approach to PfCLK3 Covalent Inhibitors.","date":"2026","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/41618901","citation_count":1,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"42345078","id":"PMC_42345078","title":"Using Unbiased Chemical Proteomics Approaches to Explore the Target Landscape of the Resistance Refractory 7-Azaindole MMV022224 in .","date":"2026","source":"ACS infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/42345078","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"42363832","id":"PMC_42363832","title":"Inhibition of PfCLK3 interferes with malaria parasite RNA splicing and explains the mechanism of action of a new class of antimalarial candidates.","date":"2026","source":"Antimicrobial agents and chemotherapy","url":"https://pubmed.ncbi.nlm.nih.gov/42363832","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCLK3"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9122,"output_tokens":2362,"usd":0.031398,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":7750,"output_tokens":3727,"usd":0.065962,"stage2_stop_reason":"end_turn"},"total_usd":0.09736,"stage1_batch_id":"msgbatch_01DisAaTypwmC8QwdMBuePHo","stage2_batch_id":"msgbatch_0184zxZTqxiEfdYYfPMfkqjb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2011,\n      \"finding\": \"Phosphorylation of PfCLK3 (CLK3/PF3D7_1114700) at tyrosine Y526 in the activation loop is essential for full kinase activity, as demonstrated by global phospho-proteomic analysis combined with functional validation.\",\n      \"method\": \"Global phospho-proteomic analysis; functional validation of phosphorylation site (Y526) as essential for kinase activity\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — phospho-proteomics identified the site and functional validation was performed, single lab with two orthogonal approaches\",\n      \"pmids\": [\"22127061\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"CLK3 (one of four PfCLKs) phosphorylates SR proteins (PfSRSF12, PfSFRS4, PfSF-1) via their Arginine/Serine-rich (RS) domains in vitro; a PfSF-1 peptide lacking the RS-rich domain was not phosphorylated. CLK3 localizes to both the nucleus and cytoplasm in asexual blood stages and gametocytes.\",\n      \"method\": \"In vitro kinase assay with recombinant SR protein substrates; immunofluorescence localization\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct in vitro kinase assay with domain-deletion control, subcellular localization shown, but single lab\",\n      \"pmids\": [\"25188378\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CLK3 (PF3D7_1114700) is essential for parasite survival at multiple life stages (asexual blood stage, liver stage, gametocyte development). Selective inhibition of CLK3 causes down-regulation of more than 400 essential parasite genes, consistent with a role in RNA splicing. Chemogenetic validation confirmed CLK3 as the target of the selective inhibitor TCMDC-135051.\",\n      \"method\": \"Selective chemical inhibition combined with chemogenetics (bumped kinase inhibitor / analog-sensitive allele strategy); transcriptomic analysis; multi-stage parasite assays including P. berghei and P. knowlesi\",\n      \"journal\": \"Science (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — chemogenetic target validation plus transcriptomics across multiple species and life stages, multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"31467193\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium knowlesi\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"The crystal/structural analysis of PfCLK3 (CLK3/PF3D7_1114700) identified key residues within the kinase catalytic site; the inhibitor altiratinib targets PfCLK3 and causes global disruption of RNA splicing (primarily intron retention) in P. falciparum. Structural features critical for binding of TCMDC-135051 to PfCLK3 were also elucidated.\",\n      \"method\": \"Genetic target deconvolution; structural analysis of kinase catalytic site; RNA sequencing to assess splicing disruption; resistance-conferring mutations identified\",\n      \"journal\": \"Science translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic deconvolution plus RNA-seq for mechanism, structural analysis, single study\",\n      \"pmids\": [\"35921477\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The co-crystal structure of PfCLK3 (CLK3/PF3D7_1114700) with reversible inhibitor TCMDC-135051 was solved, revealing a unique cysteine residue (Cys368) poorly conserved in the human kinome. Covalent inhibitors targeting Cys368 showed nanomolar potency and covalent inhibition in both recombinant protein assays and P. falciparum parasites, with efficacy persisting after 6-hour washout.\",\n      \"method\": \"Co-crystal structure determination; covalent inhibitor design and testing; recombinant protein kinase assays; parasite growth assays with washout\",\n      \"journal\": \"Journal of medicinal chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus biochemical validation with covalent inhibitors and mutagenesis-informed design, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"39441986\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Selective inhibition of PfCLK3 (CLK3/PF3D7_1114700) extensively disrupts RNA splicing: 2,039 splice junctions across 1,125 genes were mis-spliced in treated wild-type parasites compared to controls. Mis-spliced transcripts are involved in essential parasite processes across multiple life cycle stages, establishing PfCLK3 as a key regulator of spliceosome activity.\",\n      \"method\": \"RNA sequencing (RNAseq) of parasites treated with selective PfCLK3 inhibitor versus controls; wild-type vs inhibitor-resistant parasite comparison\",\n      \"journal\": \"Antimicrobial agents and chemotherapy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — selective inhibitor with resistance controls, transcriptome-wide RNA-seq, multiple orthogonal validations, direct mechanistic link established\",\n      \"pmids\": [\"42363832\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Chemical proteomics (chemical pulldown and thermal proteome profiling) demonstrated that the azaindole compound TCMDC-135051 is a selective inhibitor of PfCLK3 (CLK3/PF3D7_1114700) among the P. falciparum kinome.\",\n      \"method\": \"Chemical pulldown; thermal proteome profiling (two orthogonal chemical proteomics approaches)\",\n      \"journal\": \"ACS infectious diseases\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — two orthogonal chemical proteomics methods confirm selectivity for PfCLK3, single study\",\n      \"pmids\": [\"42345078\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Structure-based drug design targeting the catalytic lysine residue (Lys394) of PfCLK3 (CLK3/PF3D7_1114700) with benzaldehyde-based warheads resulted in covalent engagement of Lys394 confirmed by protein mass spectrometry, establishing Lys394 as a covalent targeting site distinct from Cys368.\",\n      \"method\": \"Structure-based drug design; protein mass spectrometry confirmation of covalent Lys394 engagement; recombinant protein kinase assays; parasite growth assays\",\n      \"journal\": \"RSC medicinal chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct mass spectrometry confirmation of covalent adduct, structure-informed design, single lab\",\n      \"pmids\": [\"40521344\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"PfCLK3 (PF3D7_1114700) is an essential, nuclear and cytoplasmic cyclin-dependent-like kinase whose activation requires phosphorylation at Y526 in its activation loop; it phosphorylates SR proteins via their RS-rich domains and acts as a key regulator of spliceosome activity — selective inhibition causes widespread intron retention and mis-splicing of over 1,000 genes essential across blood, liver, and sexual parasite life stages, and the kinase's catalytic site harbors a unique Cys368 (and catalytic Lys394) that can be covalently targeted by inhibitors with nanomolar parasiticidal potency.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"CLK3 (PF3D7_1114700) is an essential cyclin-dependent-like protein kinase of Plasmodium falciparum that functions as a key regulator of spliceosome activity across the parasite life cycle [#2, #5]. As a kinase, its full catalytic activity requires phosphorylation at tyrosine Y526 in its activation loop [#0], and it phosphorylates SR (serine/arginine-rich) proteins — PfSRSF12, PfSFRS4, and PfSF-1 — specifically through their Arg/Ser-rich (RS) domains, since an RS-domain-deleted PfSF-1 peptide is not a substrate [#1]. Consistent with this role in pre-mRNA splicing regulation, CLK3 localizes to both the nucleus and cytoplasm in asexual blood stages and gametocytes [#1]. CLK3 is essential for survival at multiple life stages — asexual blood stage, liver stage, and gametocyte development — and its selective inhibition causes transcriptome-wide mis-splicing, with intron retention and over 2,000 aberrant splice junctions across more than 1,000 genes involved in essential processes [#2, #3, #5]. The kinase has been chemogenetically validated as the target of the selective inhibitor TCMDC-135051 [#2, #6], and structural analysis has defined its catalytic site, including a Cys368 poorly conserved in the human kinome and a catalytic Lys394, both of which can be covalently engaged by inhibitors with nanomolar parasiticidal potency [#3, #4, #7].\",\n  \"teleology\": [\n    {\n      \"year\": 2011,\n      \"claim\": \"Establishing how CLK3 catalytic activity is switched on, phospho-proteomics identified an activation-loop tyrosine whose phosphorylation is essential for full kinase activity.\",\n      \"evidence\": \"Global phospho-proteomic analysis with functional validation of the Y526 site\",\n      \"pmids\": [\"22127061\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"The upstream kinase responsible for Y526 phosphorylation is not identified\",\n        \"Whether Y526 phosphorylation is regulated across life stages is unknown\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"To define what CLK3 acts on, in vitro kinase assays showed it phosphorylates SR proteins through their RS-rich domains, linking the kinase to the splicing machinery, and localization placed it in both nucleus and cytoplasm.\",\n      \"evidence\": \"In vitro kinase assays with recombinant SR protein substrates plus an RS-domain-deletion control; immunofluorescence localization in asexual and gametocyte stages\",\n      \"pmids\": [\"25188378\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Substrate phosphorylation shown in vitro but not confirmed in vivo\",\n        \"Cellular consequence of SR protein phosphorylation not yet demonstrated\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"To establish essentiality and therapeutic relevance, chemogenetic target validation confirmed CLK3 as the target of TCMDC-135051 and showed its inhibition kills parasites at multiple life stages while down-regulating hundreds of essential genes, consistent with a splicing role.\",\n      \"evidence\": \"Selective chemical inhibition with analog-sensitive/chemogenetic validation, transcriptomics, and multi-stage assays including P. berghei and P. knowlesi\",\n      \"pmids\": [\"31467193\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Transcriptional down-regulation was measured but direct splicing defects were not yet resolved here\",\n        \"Mechanistic connection between kinase activity and specific splicing events not established at this stage\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium knowlesi\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"To connect kinase inhibition to a defined molecular outcome, structural analysis mapped the catalytic site and RNA-seq showed that inhibition (by altiratinib and TCMDC-135051) causes global splicing disruption dominated by intron retention.\",\n      \"evidence\": \"Genetic target deconvolution, structural analysis of the catalytic site, RNA sequencing, and resistance-mutation mapping\",\n      \"pmids\": [\"35921477\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Which SR-protein phosphorylation events drive the observed intron retention is not directly resolved\",\n        \"No full-length co-crystal structure reported in this study\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"To enable durable covalent inhibition, a co-crystal structure with TCMDC-135051 revealed a Cys368 poorly conserved in the human kinome, and covalent inhibitors targeting it showed nanomolar potency with washout-resistant efficacy.\",\n      \"evidence\": \"Co-crystal structure determination, covalent inhibitor design, recombinant kinase assays, and parasite growth assays with 6-hour washout\",\n      \"pmids\": [\"39441986\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"In vivo efficacy and selectivity of Cys368-targeting covalent inhibitors not yet established\",\n        \"Resistance liability of covalent engagement not characterized\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"To resolve the scale of the splicing defect and confirm inhibitor selectivity, transcriptome-wide RNA-seq quantified mis-splicing across >1,000 genes, and orthogonal chemical proteomics confirmed TCMDC-135051 as a selective CLK3 inhibitor within the parasite kinome.\",\n      \"evidence\": \"RNA-seq of inhibitor-treated wild-type versus resistant parasites (2,039 mis-spliced junctions across 1,125 genes); chemical pulldown and thermal proteome profiling for selectivity\",\n      \"pmids\": [\"42363832\", \"42345078\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Direct catalytic mechanism linking CLK3 activity to each mis-spliced junction not resolved\",\n        \"Whether mis-splicing is a direct kinase effect or a downstream consequence not fully separated\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"To expand the covalent targeting strategy, structure-based design engaged the catalytic Lys394 with benzaldehyde warheads, establishing a covalent site distinct from Cys368.\",\n      \"evidence\": \"Structure-based drug design with protein mass spectrometry confirmation of Lys394 adduct, recombinant kinase assays, and parasite growth assays\",\n      \"pmids\": [\"40521344\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Comparative advantage of Lys394 versus Cys368 targeting not established\",\n        \"In vivo activity of Lys394-covalent compounds not reported\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CLK3-mediated SR protein phosphorylation is mechanistically coupled to specific spliceosome assembly and intron-retention events, and how CLK3 activity is regulated across the life cycle, remains open.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"In vivo substrate phosphorylation map not established\",\n        \"Upstream regulators of Y526 phosphorylation unknown\",\n        \"Direct link between individual SR-protein phosphosites and specific splicing outcomes not demonstrated\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004674\", \"supporting_discovery_ids\": [1, 4, 7]},\n      {\"term_id\": \"GO:0004713\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005737\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0008380\", \"supporting_discovery_ids\": [2, 3, 5]},\n      {\"term_id\": \"GO:0000398\", \"supporting_discovery_ids\": [3, 5]},\n      {\"term_id\": \"GO:0043484\", \"supporting_discovery_ids\": [1, 5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"PfSRSF12 (SR protein substrate)\",\n      \"PfSFRS4 (SR protein substrate)\",\n      \"PfSF-1 (SR protein substrate)\"\n    ],\n    \"other_free_text\": [\n      \"Activation requires phosphorylation at activation-loop tyrosine Y526 [#0]\",\n      \"Phosphorylates SR proteins specifically via their RS-rich domains [#1]\",\n      \"Essential across asexual blood stage, liver stage, and gametocyte development [#2]\",\n      \"Chemogenetically validated target of the selective inhibitor TCMDC-135051 [#2, #6]\",\n      \"Catalytic site harbors Cys368 (poorly conserved in the human kinome) and catalytic Lys394, both covalently targetable by nanomolar inhibitors [#4, #7]\",\n      \"Selective inhibition causes transcriptome-wide mis-splicing dominated by intron retention (2,039 junctions across 1,125 genes) [#3, #5]\"\n    ]\n  }\n}\n```","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_1114700","name":null,"product":"cyclin-dependent-like kinase CLK3","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_0933000","name":null,"product":"cyclin-dependent-like kinase CLK3, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_0912200","name":null,"product":"cyclin-dependent-like kinase CLK3, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"CLK3","evaluation":null}