{"gene":"PF3D7_0217500","run_date":"2026-09-07T10:55:51","timeline":{"discoveries":[{"year":1993,"finding":"CDPK1 (PfCPK) was shown to be a calcium-dependent serine/threonine protein kinase: recombinant full-length protein expressed in E. coli exhibited Ca2+-dependent kinase activity, demonstrating that the C-terminal EF-hand domain directly activates the N-terminal kinase domain without requiring calmodulin.","method":"Recombinant expression in E. coli, in vitro kinase assay with Ca2+ dependency","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct in vitro reconstitution of enzymatic activity with defined Ca2+ dependence, single lab but multiple biochemical validations","pmids":["8440720"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":1994,"finding":"CDPK1 has four EF-hand calcium-binding sites; EF-hand sites I and II are crucial for both Ca2+-induced conformational change and enzymatic activation (mutation at site II nearly abolishes activity; site I mutations dramatically reduce Ca2+ sensitivity), while sites III and IV have minor effects.","method":"Site-directed mutagenesis of individual EF-hand motifs (Glu→Lys or Gln), in vitro kinase assay, circular dichroism, 45Ca2+ binding","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstitution with mutagenesis and multiple orthogonal biophysical readouts in a single study","pmids":["8142371"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":1994,"finding":"Purified recombinant CDPK1 preferentially phosphorylates erythrocytic membrane proteins in vitro (with casein and histone H1 as exogenous substrates); the kinase undergoes autophosphorylation on serine and threonine residues; Ca2+ activation is partially replaceable by Mn2+ but not by Zn2+ or Mg2+; calmodulin antagonists inhibit activity; the protein is mainly expressed in ring and schizont stages and localizes to the parasitic membrane-organelle fraction.","method":"Protein purification, in vitro kinase assay, 45Ca2+ binding, autophosphorylation assay, subcellular fractionation, immunoblotting","journal":"Molecular and biochemical parasitology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — purified recombinant enzyme characterized biochemically with multiple substrates and inhibitors; localization by fractionation","pmids":["7808482"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2004,"finding":"CDPK1 contains three N-terminal membrane-anchor motifs (a myristoylation consensus, a palmitoylation site, and a basic cluster); the protein is myristoylated both endogenously and in vitro; dual acylation plus the basic cluster are required for targeting to the parasitophorous vacuole, as shown by GFP reporter mutagenesis. Immunogold EM localized the endogenous protein to the parasitophorous vacuole and the tubovesicular system.","method":"N-terminal mutagenesis, GFP reporter targeting assays, in vitro translation/myristoylation assay, immunogold electron microscopy","journal":"Molecular microbiology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct localization by immunogold EM combined with mutagenesis and GFP reporter in same study","pmids":["15491359"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2006,"finding":"The Plasmodium falciparum RKIP ortholog (PfPE-PB1) is phosphorylated by CDPK1 in vitro (at ~7-fold lower specific activity than casein) and its presence enhances CDPK1 autophosphorylation ~5.5-fold while reducing CDPK1 trans-phosphorylation of casein, indicating PfRKIP acts as both a substrate and a regulator of CDPK1 activity.","method":"Recombinant protein purification, in vitro kinase assay (autophosphorylation and substrate phosphorylation)","journal":"Molecular and biochemical parasitology","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — rigorous in vitro biochemistry but single lab, single method, no in vivo validation","pmids":["17123645"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2008,"finding":"CDPK1 is expressed during late schizogony and in sporozoites; a targeted gene-disruption approach indicated CDPK1 is essential for parasite viability; treatment with 2,6,9-trisubstituted purine inhibitors of CDPK1 causes developmental arrest at late schizont stage, linking CDPK1 to regulation of parasite motility, egress, and invasion.","method":"Gene-disruption attempt, in vitro biochemical screen (20,000 compounds), compound treatment phenotyping","journal":"Nature chemical biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — essentiality supported by failed disruption and pharmacological phenocopy, but mechanistic link is indirect","pmids":["18454143"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2008,"finding":"CDPK1 phosphorylates two glideosome motor complex components—MTIP (primarily at serine 47) and GAP45 (at two sites, one confirmed in parasite lysates phosphopeptides)—in vitro; CDPK1 localizes to the periphery of merozoites by indirect immunofluorescence; the kinase inhibitor K252a inhibits both CDPK1 activity and host cell invasion.","method":"In vitro kinase assay with recombinant substrates, mass spectrometry phosphopeptide mapping, indirect immunofluorescence, inhibitor treatment","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct in vitro phosphorylation with site identification confirmed in parasite lysates, localization data, and functional inhibitor phenotype all in one study","pmids":["18768477"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2009,"finding":"CDPK1 phosphorylates GAP45 in vitro at nine sites (Ser31, Ser89, Ser103, Ser109, Ser121, Ser149, Ser156, Thr158, Ser173); phosphorylation at Ser156/Thr158 is mutually exclusive and alters susceptibility of adjacent sites to proteolytic cleavage.","method":"In vitro phosphorylation by recombinant CDPK1, nano-UPLC-MS/MS, Ga(III)-IMAC phosphopeptide enrichment, synthetic phosphopeptide controls","journal":"Analytical biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — rigorous MS-based site mapping with multiple proteases and synthetic peptide validation in single study","pmids":["19549500"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"finding":"The C-terminal calmodulin-like domain (CamLD) of CDPK1 binds the P3 region (Leu356–Thr370) of the junction domain (JD) in a calcium-dependent manner; mutagenesis of conserved hydrophobic residues in the JD (F363A/I364A, L356A, F350A) abolishes kinase activity; a P3 peptide inhibits CDPK1 activity, blocks microneme discharge, and blocks erythrocyte invasion, directly linking the CamLD–JD interaction to CDPK1 regulation and invasion.","method":"Site-directed mutagenesis of JD, in vitro binding assay (CamLD–JD), peptide inhibition, microneme secretion assay, erythrocyte invasion assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — mutagenesis combined with direct binding evidence, functional peptide inhibition, and cellular invasion readout in one study","pmids":["23204525"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"finding":"In P. berghei, CDPK1 is essential in sexual mosquito-stage parasites: knockdown caused developmental arrest and prevented mosquito transmission independently of its proposed role in motility. Translational and transcriptional profiling of arrested parasites revealed that CDPK1 translationally activates mRNA species in the developing zygote that in macrogametes remain repressed via their 3' and 5' UTRs.","method":"Conditional knockdown in P. berghei sexual stages, translational profiling (ribosome footprinting), transcriptional profiling, mosquito infection assays","journal":"Cell host & microbe","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockdown with multiple orthogonal omic readouts and phenotypic characterization across stages","pmids":["22817984"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2012,"finding":"CDPK1 tagged with GFP localizes to the parasite plasma membrane of replicating and invasive forms and young intracellular parasites; conditional inhibition via the CDPK1 auto-inhibitory J-domain fused to GFP (J-GFP-DD) specifically binds CDPK1 in vitro and causes arrest in early schizogony when expressed in vivo, pointing to an early schizont function.","method":"GFP tagging of endogenous CDPK1, live imaging, destabilization-domain knockdown, in vitro binding of J-GFP fusion to CDPK1, inducible J-GFP-DD expression in parasites","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct subcellular localization plus specific functional inhibition with cellular phenotype, multiple orthogonal approaches","pmids":["23548171"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"finding":"CDPK1 phosphorylates GAP45 in vitro at S89, S103, and S149; this is regulated by PLC and calcium signaling; CDPK1 and PfPKB are both responsible for these GAP45 phosphorylation events; however, replacing these serine residues with alanine or aspartate had no apparent effect on GAP45 assembly into the motor complex or its subcellular localization.","method":"In vitro kinase assay, site-directed mutagenesis of GAP45 phosphosites, GFP tagging for localization, phosphorylation timing analysis in parasite development","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro kinase assay with site mapping; negative result for functional consequence of phosphorylation noted explicitly","pmids":["22558243","22479457"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"finding":"Mass spectrometry revealed CDPK1 autophosphorylation at multiple sites; mutations in the regulatory/CAD domain affect both active and inactive kinase conformations; the N-terminal extension (NTE) of CDPK1 is important for activation and contains an ATP-binding site.","method":"Mass spectrometry (autophosphorylation site mapping), site-directed mutagenesis, molecular modeling","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — MS-based autophosphorylation mapping with mutagenesis, but single lab and the ATP-binding site in NTE relies partly on modeling","pmids":["22539638"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2013,"finding":"P. berghei CDPK1 is dispensable for erythrocytic invasion, intra-erythrocytic development, sporozoite invasion of hepatocytes, hepatocyte egress, and subsequent erythrocytic cycle (conditional knockout); CDPK1 in P. berghei is essential only in mosquito sexual stages.","method":"Homologous recombination gene disruption, conditional knockout (cKO), phenotypic characterization across life stages","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean genetic disruption with stage-specific phenotyping; contradicts P. falciparum essentiality data—attributed to P. berghei specifically","pmids":["24265753"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2014,"finding":"Expression of PfCDPK1 in Toxoplasma gondii TgCDPK3 mutant rescues calcium ionophore-induced egress defect; rescue requires both plasma membrane localization and kinase activity of CDPK1; this established a surrogate system where CDPK1-specific inhibitors could be functionally validated.","method":"Heterologous complementation in T. gondii, mutagenesis of kinase activity and membrane-targeting motifs, egress assay, pharmacological inhibition","journal":"Antimicrobial agents and chemotherapy","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genetic complementation with structure-function mutagenesis and functional rescue readout","pmids":["24550330"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2015,"finding":"CDPK1 is phosphorylated by PfPKG (cGMP-dependent protein kinase), as shown by quantitative global phosphoproteomics using PKG chemical inhibition and genetic tools, positioning CDPK1 downstream of PfPKG in a signaling cascade regulating egress and invasion.","method":"Quantitative phosphoproteomics with PKG chemical inhibitor and conditional genetic tools","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — global phosphoproteomics with chemical and genetic PKG perturbation; replicated across two approaches in one study","pmids":["26149123"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2015,"finding":"CDPK1 mRNA is bound by PfAlba1 RNA-binding protein in trophozoites, repressing translation; release of CDPK1 mRNA from the PfAlba1 complex in mature stages correlates with protein synthesis, indicating PfAlba1-mediated translational repression of CDPK1 in trophozoites.","method":"RIP-seq (deep sequencing of affinity-purified PfAlba1-associated RNAs), overexpression of epitope-tagged PfAlba1, mRNA homeostasis and translation analysis","journal":"Genome biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct RIP-seq identification of CDPK1 mRNA as PfAlba1 target with correlation to translation state; single lab","pmids":["26415947"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2016,"finding":"Reduced transphosphorylation activity of CDPK1 caused by the T145M gatekeeper mutation is compensated in the parasite through PKG activity (or a kinase under PKG regulation), with CDPK5 and CDPK6 transcripts significantly upregulated in T145M parasites.","method":"CRISPR/Cas9 gatekeeper substitution, bumped kinase inhibitor (BKI 1294) dose-response in vitro and in parasites, PKG inhibitor (C2) sensitivity testing, RNA-seq transcript quantification","journal":"mBio","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic engineering with pharmacological epistasis testing; compensatory pathway is inferred rather than directly demonstrated","pmids":["27923926"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2017,"finding":"Conditional knockdown of CDPK1 established it is critical for host erythrocyte invasion; comparative phosphoproteomics identified CDPK1 substrates including Inner Membrane Complex proteins and glideosome-actomyosin motor components; CDPK1 phosphorylates the PfPKA regulatory subunit (PfPKA-R) and thereby regulates PfPKA activity in the parasite.","method":"Conditional knockdown (inducible), comparative phosphoproteomics, in vitro kinase assay, erythrocyte invasion assay","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional knockdown with phosphoproteomics and in vitro validation; PKA crosstalk supported by phosphorylation of PKA-R","pmids":["28680058"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2018,"finding":"PfCDPK1 interacts with PfSERA5 (immunoprecipitation, co-sedimentation, co-immunolocalization) and phosphorylates PfSERA5 in vitro in a Ca2+-dependent manner, enhancing its proteolytic activity; the CDPK1 inhibitor purfalcamine blocked PfSERA5 phosphorylation and activation both in vitro and in schizonts, blocking merozoite egress.","method":"Immunoprecipitation (anti-PfSERA5 followed by MS), co-sedimentation, co-immunolocalization, in vitro kinase assay, purfalcamine inhibitor treatment, egress assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — interaction identified by co-IP/MS and orthogonally confirmed by co-sedimentation and co-immunolocalization; functional consequence via inhibitor and egress phenotype","pmids":["29716996"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2018,"finding":"CDPK1 was successfully disrupted in P. falciparum only in a background with the T145M gatekeeper mutation (reduced activity); KO parasites show slow asexual growth, defects in both male and female gametogenesis, and cannot establish mosquito infection; complementation with full-length CDPK1 partially rescues asexual growth and mosquito infection; CDPK1 KO schizonts show elevated gametocyte-specific gene transcripts.","method":"CRISPR/Cas9 gene disruption, complementation, phenotypic analysis (growth rate, gametogenesis, mosquito infection), RNA-seq","journal":"PNAS","confidence":"High","confidence_rationale":"Tier 2 / Strong — definitive KO with complementation across multiple life stages and orthogonal molecular readout (RNA-seq)","pmids":["29311293"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"CDPK1 is dynamically palmitoylated in P. falciparum merozoites and localizes to the merozoite membrane; exposure to low [K+] activates palmitoyl acyl transferase (PAT) activity, which is required for microneme secretion; the PAT inhibitor 2-bromopalmitate blocks microneme secretion and RBC invasion, linking dynamic palmitoylation of CDPK1 to its membrane localization and invasion function.","method":"Acyl biotin exchange (ABE) chemistry, copper-catalyzed alkyne-azide chemistry (CuAAC) imaging, confocal microscopy, pharmacological inhibition, microneme secretion assay, RBC invasion assay","journal":"ACS infectious diseases","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct demonstration of palmitoylation with localization imaging; functional link to invasion via PAT inhibitor, but the inhibitor is not CDPK1-specific","pmids":["32003970"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"CDPK1 phosphorylates MTRAP cytoplasmic tail domain in vitro, and this phosphorylation increases MTRAP affinity for aldolase ~10-fold, suggesting CDPK1-mediated phosphorylation dynamically modulates coupling of the actomyosin motor to surface adhesins during invasion.","method":"In vitro kinase assay (CDPK1 + MTRAP CTD), direct binding assay (MTRAP CTD vs. aldolase), single amino acid substitutions in MTRAP CTD","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — direct in vitro phosphorylation with binding consequence, but physiological phosphorylation of MTRAP by CDPK1 was not detected in tagged parasites","pmids":["27607074"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"CDPK1 is phosphorylated in a Ca2+-dependent manner in merozoites; Pf14-3-3I binds phosphorylated CDPK1 (at the canonical Mode I RXXpS motif centered on 61KLGpS64) and assembles a multiprotein signaling complex together with PfPKA-R; disruption of this complex with a competing phosphopeptide inhibits microneme secretion and RBC invasion.","method":"Quantitative phosphoproteomics (high/low K+ conditions), co-immunoprecipitation, gel filtration chromatography, ELISA, SPR, molecular dynamics simulation, phosphopeptide competition assay, invasion assay","journal":"mBio","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP and gel filtration for complex validation; phosphoproteomics for site identification; functional disruption with phosphopeptide; multiple orthogonal methods across two independent studies (pmids 32817103 and 32484216)","pmids":["32817103","32484216"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"CDPK1 in P. berghei is required for optimal sporozoite motility and hepatocyte invasion; increased cGMP can compensate for loss of CDPK1 (and CDPK5) during sporozoite invasion but not for loss of CDPK4; CDPK1 expression is downregulated after sporozoite invasion.","method":"Conditional knockout (cKO) in P. berghei, sporozoite motility assay, hepatocyte invasion assay, cGMP supplementation rescue experiment","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic depletion with defined motility and invasion phenotypes; cGMP epistasis tested pharmacologically","pmids":["32866196"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2020,"finding":"CDPK1 is a candidate kinase for RhopH3 serine 804 phosphorylation; CDPK1 knockdown reduces RhopH3 secretion from the parasite, linking CDPK1 activity to rhoptry discharge during invasion.","method":"CRISPR-Cas9 phosphomutant (S804A) of RhopH3, conditional knockdown of CDPK1, rhoptry secretion assay","journal":"mBio","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — CDPK1 identified as candidate kinase based on knockdown effect on secretion; direct phosphorylation of RhopH3 by CDPK1 not directly demonstrated in vitro","pmids":["33024030"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"DHHC2 palmitoyl-acyl-transferase, the major resident PAT of the P. yoelii inner membrane complex (IMC), palmitoylates CDPK1 and GAP45, and this palmitoylation is required for their IMC localization; depletion of DHHC2 leads to defective schizont segmentation.","method":"TurboID proximity labeling proteomics, IMC-proteome compilation, palmitome cross-referencing, conditional DHHC2 depletion, fluorescence localization of CDPK1 and GAP45 in DHHC2-depleted parasites","journal":"eLife","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct evidence that DHHC2 depletion mislocalizes CDPK1; palmitoylation of CDPK1 by DHHC2 inferred from palmitome and proximity labeling rather than direct in vitro assay","pmids":["35775739"],"is_preprint":false,"attribution":[{"species":"Plasmodium yoelii","strain":""}]},{"year":2023,"finding":"FBXO1-dependent ubiquitination interplays with CDPK1-mediated phosphorylation in P. berghei; ubiquitinomic surveys show FBXO1-dependent ubiquitination of proteins important for egress and IMC organization, with an additional layer of regulation via CDPK1 phosphorylation.","method":"Ubiquitinomics (proteomics of FBXO1-dependent ubiquitinated proteins), co-immunoprecipitation, genetic disruption of FBXO1","journal":"Nature communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — interplay between FBXO1-ubiquitination and CDPK1-phosphorylation demonstrated at proteomic level but direct mechanistic link is not fully resolved","pmids":["36898988"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2024,"finding":"PP7 (protein phosphatase 7) interacts with CDPK1 in P. falciparum, as determined by co-immunoprecipitation, consistent with a role for CDPK1 in the calcium signaling network that PP7 participates in.","method":"Co-immunoprecipitation, conditional disruption of PP7, phosphoproteomics","journal":"mBio","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP demonstrating CDPK1-PP7 interaction; no functional consequence of the interaction directly tested","pmids":["39387582"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2025,"finding":"PfRKIP interacts with CDPK1 within P. falciparum parasites (confirmed by immunofluorescence and proximity biotinylation); PfRKIP regulates CDPK1 kinase activity; in the presence of a substrate, CDPK1 hyper-phosphorylates PfRKIP causing its dissociation from CDPK1, thereby allowing CDPK1 to trans-phosphorylate other substrates.","method":"ELISA (in vitro binding), immunofluorescence assay (co-localization in parasites), proximity biotinylation (TurboID), in vitro kinase assay, in silico docking and mutagenesis of PEBP domain","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — interaction validated by proximity biotinylation in situ and ELISA in vitro; regulatory mechanism demonstrated by kinase assay; single lab","pmids":["39842334"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"PF3D7_0217500 (CDPK1) is a calcium-directly-activated serine/threonine kinase whose EF-hand domain (sites I and II critical) activates the kinase domain intramolecularly via the junction domain; it is dually acylated (N-myristoylation + palmitoylation, the latter mediated by DHHC2) and membrane-targeted to the IMC/parasite plasma membrane periphery, where it phosphorylates motor complex components (MTIP-S47, GAP45 at multiple serines), PfSERA5 (promoting egress), the PKA regulatory subunit (modulating PKA activity), and likely RhopH3-S804 (regulating rhoptry secretion); CDPK1 itself is phosphorylated by PfPKG upstream, forms a Pf14-3-3I–PKA–CDPK1 multiprotein complex required for merozoite invasion, and is subject to translational repression by PfAlba1 in trophozoites; in P. falciparum it is essential for asexual blood-stage growth, microneme secretion, erythrocyte invasion, and gametogenesis, whereas in P. berghei blood and liver stages it is dispensable but required in mosquito sexual stages and for sporozoite motility."},"narrative":{"mechanistic_narrative":"PF3D7_0217500 (CDPK1) is a calcium-directly-activated serine/threonine protein kinase that coordinates the motility, secretory, and egress machinery driving Plasmodium erythrocyte invasion and sexual-stage development [PMID:8440720, PMID:28680058]. Its enzymatic activity is switched on intramolecularly: the C-terminal EF-hand/calmodulin-like domain binds Ca2+ (EF-hand sites I and II being decisive) and engages the junction domain P3 region to relieve autoinhibition and activate the kinase without calmodulin, a regulatory interface whose disruption blocks microneme discharge and invasion [PMID:8440720, PMID:8142371, PMID:23204525]. The protein is dually acylated through an N-terminal myristoylation-plus-palmitoylation-plus-basic-cluster module that targets it to the parasite membrane periphery; palmitoylation is dynamic and, in P. yoelii, is delivered by the IMC palmitoyl-acyl-transferase DHHC2, tying membrane localization to microneme secretion and invasion [PMID:15491359, PMID:32003970, PMID:35775739]. At its membrane location CDPK1 phosphorylates components of the glideosome actomyosin motor (MTIP at Ser47 and GAP45 at multiple serines) and the adhesin adaptor MTRAP, and phosphorylates PfSERA5 to enhance its protease activity and promote merozoite egress [PMID:18768477, PMID:19549500, PMID:29716996, PMID:27607074]. CDPK1 is embedded in a signalling network: it acts downstream of the cGMP-dependent kinase PfPKG, phosphorylates the PfPKA regulatory subunit, and assembles a phospho-dependent Pf14-3-3I–PfPKA-R complex required for microneme secretion and invasion [PMID:26149123, PMID:28680058, PMID:32817103, PMID:32484216]. Genetic ablation confirms CDPK1 is essential for P. falciparum asexual growth, invasion, and gametogenesis, whereas in P. berghei it is dispensable in blood and liver stages and required instead for sexual mosquito-stage development and optimal sporozoite motility [PMID:29311293, PMID:24265753, PMID:32866196, PMID:22817984].","teleology":[{"year":1993,"claim":"Establishing that CDPK1 is a bona fide calcium-activated kinase answered whether a single polypeptide could couple Ca2+ sensing to catalysis without an accessory calmodulin.","evidence":"Recombinant full-length protein in E. coli with Ca2+-dependent in vitro kinase assay","pmids":["8440720"],"confidence":"High","gaps":["No physiological substrates identified at this stage","Mechanism of intramolecular activation not resolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":1994,"claim":"Dissecting the four EF-hand motifs defined which Ca2+-binding sites drive the activating conformational change, localizing the regulatory switch to sites I and II.","evidence":"Site-directed mutagenesis of EF-hand motifs with in vitro kinase assay, CD, and 45Ca2+ binding; plus biochemical characterization of substrate preference, autophosphorylation, and membrane-fraction localization","pmids":["8142371","7808482"],"confidence":"High","gaps":["Structural basis of EF-hand-to-kinase coupling not defined","In vitro substrates (casein, histone) not physiological targets"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2004,"claim":"Identifying the N-terminal acylation/basic-cluster module answered how a soluble kinase is anchored to membranes and directed to secretory compartments.","evidence":"N-terminal mutagenesis, GFP reporter targeting, in vitro myristoylation, and immunogold EM in P. falciparum","pmids":["15491359"],"confidence":"High","gaps":["Enzyme responsible for palmitoylation not identified here","Functional consequence of membrane targeting not tested genetically"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2008,"claim":"Linking CDPK1 to the glideosome motor and demonstrating essentiality established its role in the invasion/egress machinery and validated it as a drug target.","evidence":"Failed gene disruption plus inhibitor phenotyping; in vitro phosphorylation of MTIP (Ser47) and GAP45 with MS site mapping, IFA localization, and invasion-blocking inhibitors","pmids":["18454143","18768477"],"confidence":"High","gaps":["Functional impact of motor-component phosphorylation not directly shown","Essentiality inferred from failed disruption rather than conditional knockout"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2009,"claim":"Comprehensive mapping of GAP45 phosphosites clarified the extent and regulatory logic of CDPK1 modification of a motor anchor.","evidence":"In vitro phosphorylation with nano-UPLC-MS/MS, IMAC enrichment, and synthetic phosphopeptide controls","pmids":["19549500"],"confidence":"High","gaps":["Physiological occupancy of these sites in parasites not established","Functional readout of individual sites absent"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"claim":"Defining the CamLD–junction domain P3 interaction resolved the structural mechanism of intramolecular autoinhibition and provided a peptide tool that blocks invasion.","evidence":"Junction-domain mutagenesis, CamLD–JD binding assay, P3 peptide inhibition, microneme and invasion assays; plus autophosphorylation/NTE mapping and GFP-localization/J-domain knockdown","pmids":["23204525","22539638","23548171"],"confidence":"High","gaps":["Full activated-state structure not solved","NTE ATP-binding site partly modeling-dependent"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"claim":"Genetic work in P. berghei revealed a stage-restricted essentiality and an unexpected role for CDPK1 as a translational activator in the developing zygote.","evidence":"Conditional knockdown in P. berghei sexual stages with ribosome footprinting, transcriptional profiling, and mosquito infection assays","pmids":["22817984"],"confidence":"High","gaps":["Molecular mechanism by which CDPK1 activates translation unknown","Direct RNA/ribosome targets of CDPK1 not defined"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2013,"claim":"A clean P. berghei conditional knockout established species-divergent essentiality: dispensable in blood and liver stages, essential only in mosquito sexual stages.","evidence":"Homologous-recombination disruption and conditional knockout with stage-specific phenotyping in P. berghei","pmids":["24265753"],"confidence":"High","gaps":["Basis for divergence from P. falciparum essentiality not explained","Redundant kinases masking blood-stage phenotype not identified"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2014,"claim":"Heterologous rescue of a T. gondii CDPK mutant demonstrated that CDPK1 function requires both membrane localization and kinase activity, and built a surrogate for inhibitor validation.","evidence":"Complementation of T. gondii TgCDPK3 mutant with membrane/kinase-dead mutagenesis and egress assays","pmids":["24550330"],"confidence":"High","gaps":["Native P. falciparum substrates driving egress in this assay not defined","Cross-species functional equivalence limits mechanistic inference"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2015,"claim":"Placing CDPK1 downstream of PfPKG and mapping PfAlba1 repression of CDPK1 mRNA situated the kinase within phospho- and translational-control cascades governing egress/invasion.","evidence":"Quantitative phosphoproteomics with PKG chemical/genetic perturbation; RIP-seq of PfAlba1-bound CDPK1 mRNA with translation-state analysis","pmids":["26149123","26415947"],"confidence":"Medium","gaps":["PfPKG phosphosite(s) on CDPK1 and their functional consequence not defined","Direct effect of PfAlba1 release on CDPK1 protein levels only correlative"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2016,"claim":"Gatekeeper mutation studies exposed pathway compensation, showing PKG-linked activity buffers reduced CDPK1 function.","evidence":"CRISPR/Cas9 T145M substitution with bumped-kinase and PKG inhibitor epistasis and RNA-seq of CDPK5/CDPK6","pmids":["27923926"],"confidence":"Medium","gaps":["Compensating kinase not directly demonstrated","Transcript upregulation not shown to restore function"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2017,"claim":"Conditional knockdown plus comparative phosphoproteomics confirmed the invasion requirement and revealed CDPK1–PKA crosstalk via phosphorylation of the PKA regulatory subunit.","evidence":"Inducible 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Plasmodium falciparum.","date":"2022","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/35709874","citation_count":1,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CDPK1","calcium-dependent protein kinase 1","PfCDPK1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"38915420","id":"PMC_38915420","title":"Amodiaquine drug pressure selects nonsynonymous mutations in pantothenate kinase 1, diacylglycerol kinase, and phosphatidylinositol-4 kinase in Plasmodium berghei ANKA.","date":"2023","source":"Open research Africa","url":"https://pubmed.ncbi.nlm.nih.gov/38915420","citation_count":1,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CDPK1","calcium-dependent protein kinase 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JoVE","url":"https://pubmed.ncbi.nlm.nih.gov/39651747","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["CDPK1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"40339062","id":"PMC_40339062","title":"Versatile Imidazole Scaffold with Potent Activity against Multiple Apicomplexan Parasites.","date":"2025","source":"ACS infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/40339062","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["calcium-dependent protein kinase 1","PfCDPK1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"41633918","id":"PMC_41633918","title":"Corrigendum to \"Plasmodium falciparum Raf kinase inhibitor is a lipid binding protein that interacts with and regulates the activity of PfCDPK1, an essential plant-like kinase required for red blood cell invasion\" [Biochem. Biophys. Res. Commun. 749 (2025) 151350].","date":"2026","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/41633918","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCDPK1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"42213905","id":"PMC_42213905","title":"Harnessing the Quinoline Scaffold toward Discovery and Development of Antimalarials.","date":"2026","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/42213905","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PfCDPK1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":34115,"output_tokens":8650,"usd":0.116047,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":16684,"output_tokens":6638,"usd":0.124685,"stage2_stop_reason":"end_turn"},"total_usd":0.240732,"stage1_batch_id":"msgbatch_01DbiymDmubkPpYvdbAu5a7V","stage2_batch_id":"msgbatch_012TbrWvMRH129T7PQ4SmvrJ","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1993,\n      \"finding\": \"CDPK1 (PfCPK) was shown to be a calcium-dependent serine/threonine protein kinase: recombinant full-length protein expressed in E. coli exhibited Ca2+-dependent kinase activity, demonstrating that the C-terminal EF-hand domain directly activates the N-terminal kinase domain without requiring calmodulin.\",\n      \"method\": \"Recombinant expression in E. coli, in vitro kinase assay with Ca2+ dependency\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro reconstitution of enzymatic activity with defined Ca2+ dependence, single lab but multiple biochemical validations\",\n      \"pmids\": [\"8440720\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"CDPK1 has four EF-hand calcium-binding sites; EF-hand sites I and II are crucial for both Ca2+-induced conformational change and enzymatic activation (mutation at site II nearly abolishes activity; site I mutations dramatically reduce Ca2+ sensitivity), while sites III and IV have minor effects.\",\n      \"method\": \"Site-directed mutagenesis of individual EF-hand motifs (Glu→Lys or Gln), in vitro kinase assay, circular dichroism, 45Ca2+ binding\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstitution with mutagenesis and multiple orthogonal biophysical readouts in a single study\",\n      \"pmids\": [\"8142371\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"Purified recombinant CDPK1 preferentially phosphorylates erythrocytic membrane proteins in vitro (with casein and histone H1 as exogenous substrates); the kinase undergoes autophosphorylation on serine and threonine residues; Ca2+ activation is partially replaceable by Mn2+ but not by Zn2+ or Mg2+; calmodulin antagonists inhibit activity; the protein is mainly expressed in ring and schizont stages and localizes to the parasitic membrane-organelle fraction.\",\n      \"method\": \"Protein purification, in vitro kinase assay, 45Ca2+ binding, autophosphorylation assay, subcellular fractionation, immunoblotting\",\n      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — purified recombinant enzyme characterized biochemically with multiple substrates and inhibitors; localization by fractionation\",\n      \"pmids\": [\"7808482\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"CDPK1 contains three N-terminal membrane-anchor motifs (a myristoylation consensus, a palmitoylation site, and a basic cluster); the protein is myristoylated both endogenously and in vitro; dual acylation plus the basic cluster are required for targeting to the parasitophorous vacuole, as shown by GFP reporter mutagenesis. Immunogold EM localized the endogenous protein to the parasitophorous vacuole and the tubovesicular system.\",\n      \"method\": \"N-terminal mutagenesis, GFP reporter targeting assays, in vitro translation/myristoylation assay, immunogold electron microscopy\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization by immunogold EM combined with mutagenesis and GFP reporter in same study\",\n      \"pmids\": [\"15491359\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"The Plasmodium falciparum RKIP ortholog (PfPE-PB1) is phosphorylated by CDPK1 in vitro (at ~7-fold lower specific activity than casein) and its presence enhances CDPK1 autophosphorylation ~5.5-fold while reducing CDPK1 trans-phosphorylation of casein, indicating PfRKIP acts as both a substrate and a regulator of CDPK1 activity.\",\n      \"method\": \"Recombinant protein purification, in vitro kinase assay (autophosphorylation and substrate phosphorylation)\",\n      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — rigorous in vitro biochemistry but single lab, single method, no in vivo validation\",\n      \"pmids\": [\"17123645\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"CDPK1 is expressed during late schizogony and in sporozoites; a targeted gene-disruption approach indicated CDPK1 is essential for parasite viability; treatment with 2,6,9-trisubstituted purine inhibitors of CDPK1 causes developmental arrest at late schizont stage, linking CDPK1 to regulation of parasite motility, egress, and invasion.\",\n      \"method\": \"Gene-disruption attempt, in vitro biochemical screen (20,000 compounds), compound treatment phenotyping\",\n      \"journal\": \"Nature chemical biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — essentiality supported by failed disruption and pharmacological phenocopy, but mechanistic link is indirect\",\n      \"pmids\": [\"18454143\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"CDPK1 phosphorylates two glideosome motor complex components—MTIP (primarily at serine 47) and GAP45 (at two sites, one confirmed in parasite lysates phosphopeptides)—in vitro; CDPK1 localizes to the periphery of merozoites by indirect immunofluorescence; the kinase inhibitor K252a inhibits both CDPK1 activity and host cell invasion.\",\n      \"method\": \"In vitro kinase assay with recombinant substrates, mass spectrometry phosphopeptide mapping, indirect immunofluorescence, inhibitor treatment\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct in vitro phosphorylation with site identification confirmed in parasite lysates, localization data, and functional inhibitor phenotype all in one study\",\n      \"pmids\": [\"18768477\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"CDPK1 phosphorylates GAP45 in vitro at nine sites (Ser31, Ser89, Ser103, Ser109, Ser121, Ser149, Ser156, Thr158, Ser173); phosphorylation at Ser156/Thr158 is mutually exclusive and alters susceptibility of adjacent sites to proteolytic cleavage.\",\n      \"method\": \"In vitro phosphorylation by recombinant CDPK1, nano-UPLC-MS/MS, Ga(III)-IMAC phosphopeptide enrichment, synthetic phosphopeptide controls\",\n      \"journal\": \"Analytical biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — rigorous MS-based site mapping with multiple proteases and synthetic peptide validation in single study\",\n      \"pmids\": [\"19549500\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"The C-terminal calmodulin-like domain (CamLD) of CDPK1 binds the P3 region (Leu356–Thr370) of the junction domain (JD) in a calcium-dependent manner; mutagenesis of conserved hydrophobic residues in the JD (F363A/I364A, L356A, F350A) abolishes kinase activity; a P3 peptide inhibits CDPK1 activity, blocks microneme discharge, and blocks erythrocyte invasion, directly linking the CamLD–JD interaction to CDPK1 regulation and invasion.\",\n      \"method\": \"Site-directed mutagenesis of JD, in vitro binding assay (CamLD–JD), peptide inhibition, microneme secretion assay, erythrocyte invasion assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis combined with direct binding evidence, functional peptide inhibition, and cellular invasion readout in one study\",\n      \"pmids\": [\"23204525\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"In P. berghei, CDPK1 is essential in sexual mosquito-stage parasites: knockdown caused developmental arrest and prevented mosquito transmission independently of its proposed role in motility. Translational and transcriptional profiling of arrested parasites revealed that CDPK1 translationally activates mRNA species in the developing zygote that in macrogametes remain repressed via their 3' and 5' UTRs.\",\n      \"method\": \"Conditional knockdown in P. berghei sexual stages, translational profiling (ribosome footprinting), transcriptional profiling, mosquito infection assays\",\n      \"journal\": \"Cell host & microbe\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockdown with multiple orthogonal omic readouts and phenotypic characterization across stages\",\n      \"pmids\": [\"22817984\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"CDPK1 tagged with GFP localizes to the parasite plasma membrane of replicating and invasive forms and young intracellular parasites; conditional inhibition via the CDPK1 auto-inhibitory J-domain fused to GFP (J-GFP-DD) specifically binds CDPK1 in vitro and causes arrest in early schizogony when expressed in vivo, pointing to an early schizont function.\",\n      \"method\": \"GFP tagging of endogenous CDPK1, live imaging, destabilization-domain knockdown, in vitro binding of J-GFP fusion to CDPK1, inducible J-GFP-DD expression in parasites\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct subcellular localization plus specific functional inhibition with cellular phenotype, multiple orthogonal approaches\",\n      \"pmids\": [\"23548171\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"CDPK1 phosphorylates GAP45 in vitro at S89, S103, and S149; this is regulated by PLC and calcium signaling; CDPK1 and PfPKB are both responsible for these GAP45 phosphorylation events; however, replacing these serine residues with alanine or aspartate had no apparent effect on GAP45 assembly into the motor complex or its subcellular localization.\",\n      \"method\": \"In vitro kinase assay, site-directed mutagenesis of GAP45 phosphosites, GFP tagging for localization, phosphorylation timing analysis in parasite development\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro kinase assay with site mapping; negative result for functional consequence of phosphorylation noted explicitly\",\n      \"pmids\": [\"22558243\", \"22479457\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Mass spectrometry revealed CDPK1 autophosphorylation at multiple sites; mutations in the regulatory/CAD domain affect both active and inactive kinase conformations; the N-terminal extension (NTE) of CDPK1 is important for activation and contains an ATP-binding site.\",\n      \"method\": \"Mass spectrometry (autophosphorylation site mapping), site-directed mutagenesis, molecular modeling\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — MS-based autophosphorylation mapping with mutagenesis, but single lab and the ATP-binding site in NTE relies partly on modeling\",\n      \"pmids\": [\"22539638\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"P. berghei CDPK1 is dispensable for erythrocytic invasion, intra-erythrocytic development, sporozoite invasion of hepatocytes, hepatocyte egress, and subsequent erythrocytic cycle (conditional knockout); CDPK1 in P. berghei is essential only in mosquito sexual stages.\",\n      \"method\": \"Homologous recombination gene disruption, conditional knockout (cKO), phenotypic characterization across life stages\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic disruption with stage-specific phenotyping; contradicts P. falciparum essentiality data—attributed to P. berghei specifically\",\n      \"pmids\": [\"24265753\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Expression of PfCDPK1 in Toxoplasma gondii TgCDPK3 mutant rescues calcium ionophore-induced egress defect; rescue requires both plasma membrane localization and kinase activity of CDPK1; this established a surrogate system where CDPK1-specific inhibitors could be functionally validated.\",\n      \"method\": \"Heterologous complementation in T. gondii, mutagenesis of kinase activity and membrane-targeting motifs, egress assay, pharmacological inhibition\",\n      \"journal\": \"Antimicrobial agents and chemotherapy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic complementation with structure-function mutagenesis and functional rescue readout\",\n      \"pmids\": [\"24550330\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"CDPK1 is phosphorylated by PfPKG (cGMP-dependent protein kinase), as shown by quantitative global phosphoproteomics using PKG chemical inhibition and genetic tools, positioning CDPK1 downstream of PfPKG in a signaling cascade regulating egress and invasion.\",\n      \"method\": \"Quantitative phosphoproteomics with PKG chemical inhibitor and conditional genetic tools\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — global phosphoproteomics with chemical and genetic PKG perturbation; replicated across two approaches in one study\",\n      \"pmids\": [\"26149123\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"CDPK1 mRNA is bound by PfAlba1 RNA-binding protein in trophozoites, repressing translation; release of CDPK1 mRNA from the PfAlba1 complex in mature stages correlates with protein synthesis, indicating PfAlba1-mediated translational repression of CDPK1 in trophozoites.\",\n      \"method\": \"RIP-seq (deep sequencing of affinity-purified PfAlba1-associated RNAs), overexpression of epitope-tagged PfAlba1, mRNA homeostasis and translation analysis\",\n      \"journal\": \"Genome biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct RIP-seq identification of CDPK1 mRNA as PfAlba1 target with correlation to translation state; single lab\",\n      \"pmids\": [\"26415947\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Reduced transphosphorylation activity of CDPK1 caused by the T145M gatekeeper mutation is compensated in the parasite through PKG activity (or a kinase under PKG regulation), with CDPK5 and CDPK6 transcripts significantly upregulated in T145M parasites.\",\n      \"method\": \"CRISPR/Cas9 gatekeeper substitution, bumped kinase inhibitor (BKI 1294) dose-response in vitro and in parasites, PKG inhibitor (C2) sensitivity testing, RNA-seq transcript quantification\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic engineering with pharmacological epistasis testing; compensatory pathway is inferred rather than directly demonstrated\",\n      \"pmids\": [\"27923926\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Conditional knockdown of CDPK1 established it is critical for host erythrocyte invasion; comparative phosphoproteomics identified CDPK1 substrates including Inner Membrane Complex proteins and glideosome-actomyosin motor components; CDPK1 phosphorylates the PfPKA regulatory subunit (PfPKA-R) and thereby regulates PfPKA activity in the parasite.\",\n      \"method\": \"Conditional knockdown (inducible), comparative phosphoproteomics, in vitro kinase assay, erythrocyte invasion assay\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional knockdown with phosphoproteomics and in vitro validation; PKA crosstalk supported by phosphorylation of PKA-R\",\n      \"pmids\": [\"28680058\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"PfCDPK1 interacts with PfSERA5 (immunoprecipitation, co-sedimentation, co-immunolocalization) and phosphorylates PfSERA5 in vitro in a Ca2+-dependent manner, enhancing its proteolytic activity; the CDPK1 inhibitor purfalcamine blocked PfSERA5 phosphorylation and activation both in vitro and in schizonts, blocking merozoite egress.\",\n      \"method\": \"Immunoprecipitation (anti-PfSERA5 followed by MS), co-sedimentation, co-immunolocalization, in vitro kinase assay, purfalcamine inhibitor treatment, egress assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — interaction identified by co-IP/MS and orthogonally confirmed by co-sedimentation and co-immunolocalization; functional consequence via inhibitor and egress phenotype\",\n      \"pmids\": [\"29716996\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"CDPK1 was successfully disrupted in P. falciparum only in a background with the T145M gatekeeper mutation (reduced activity); KO parasites show slow asexual growth, defects in both male and female gametogenesis, and cannot establish mosquito infection; complementation with full-length CDPK1 partially rescues asexual growth and mosquito infection; CDPK1 KO schizonts show elevated gametocyte-specific gene transcripts.\",\n      \"method\": \"CRISPR/Cas9 gene disruption, complementation, phenotypic analysis (growth rate, gametogenesis, mosquito infection), RNA-seq\",\n      \"journal\": \"PNAS\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — definitive KO with complementation across multiple life stages and orthogonal molecular readout (RNA-seq)\",\n      \"pmids\": [\"29311293\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CDPK1 is dynamically palmitoylated in P. falciparum merozoites and localizes to the merozoite membrane; exposure to low [K+] activates palmitoyl acyl transferase (PAT) activity, which is required for microneme secretion; the PAT inhibitor 2-bromopalmitate blocks microneme secretion and RBC invasion, linking dynamic palmitoylation of CDPK1 to its membrane localization and invasion function.\",\n      \"method\": \"Acyl biotin exchange (ABE) chemistry, copper-catalyzed alkyne-azide chemistry (CuAAC) imaging, confocal microscopy, pharmacological inhibition, microneme secretion assay, RBC invasion assay\",\n      \"journal\": \"ACS infectious diseases\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct demonstration of palmitoylation with localization imaging; functional link to invasion via PAT inhibitor, but the inhibitor is not CDPK1-specific\",\n      \"pmids\": [\"32003970\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CDPK1 phosphorylates MTRAP cytoplasmic tail domain in vitro, and this phosphorylation increases MTRAP affinity for aldolase ~10-fold, suggesting CDPK1-mediated phosphorylation dynamically modulates coupling of the actomyosin motor to surface adhesins during invasion.\",\n      \"method\": \"In vitro kinase assay (CDPK1 + MTRAP CTD), direct binding assay (MTRAP CTD vs. aldolase), single amino acid substitutions in MTRAP CTD\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — direct in vitro phosphorylation with binding consequence, but physiological phosphorylation of MTRAP by CDPK1 was not detected in tagged parasites\",\n      \"pmids\": [\"27607074\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CDPK1 is phosphorylated in a Ca2+-dependent manner in merozoites; Pf14-3-3I binds phosphorylated CDPK1 (at the canonical Mode I RXXpS motif centered on 61KLGpS64) and assembles a multiprotein signaling complex together with PfPKA-R; disruption of this complex with a competing phosphopeptide inhibits microneme secretion and RBC invasion.\",\n      \"method\": \"Quantitative phosphoproteomics (high/low K+ conditions), co-immunoprecipitation, gel filtration chromatography, ELISA, SPR, molecular dynamics simulation, phosphopeptide competition assay, invasion assay\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP and gel filtration for complex validation; phosphoproteomics for site identification; functional disruption with phosphopeptide; multiple orthogonal methods across two independent studies (pmids 32817103 and 32484216)\",\n      \"pmids\": [\"32817103\", \"32484216\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CDPK1 in P. berghei is required for optimal sporozoite motility and hepatocyte invasion; increased cGMP can compensate for loss of CDPK1 (and CDPK5) during sporozoite invasion but not for loss of CDPK4; CDPK1 expression is downregulated after sporozoite invasion.\",\n      \"method\": \"Conditional knockout (cKO) in P. berghei, sporozoite motility assay, hepatocyte invasion assay, cGMP supplementation rescue experiment\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic depletion with defined motility and invasion phenotypes; cGMP epistasis tested pharmacologically\",\n      \"pmids\": [\"32866196\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"CDPK1 is a candidate kinase for RhopH3 serine 804 phosphorylation; CDPK1 knockdown reduces RhopH3 secretion from the parasite, linking CDPK1 activity to rhoptry discharge during invasion.\",\n      \"method\": \"CRISPR-Cas9 phosphomutant (S804A) of RhopH3, conditional knockdown of CDPK1, rhoptry secretion assay\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — CDPK1 identified as candidate kinase based on knockdown effect on secretion; direct phosphorylation of RhopH3 by CDPK1 not directly demonstrated in vitro\",\n      \"pmids\": [\"33024030\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"DHHC2 palmitoyl-acyl-transferase, the major resident PAT of the P. yoelii inner membrane complex (IMC), palmitoylates CDPK1 and GAP45, and this palmitoylation is required for their IMC localization; depletion of DHHC2 leads to defective schizont segmentation.\",\n      \"method\": \"TurboID proximity labeling proteomics, IMC-proteome compilation, palmitome cross-referencing, conditional DHHC2 depletion, fluorescence localization of CDPK1 and GAP45 in DHHC2-depleted parasites\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct evidence that DHHC2 depletion mislocalizes CDPK1; palmitoylation of CDPK1 by DHHC2 inferred from palmitome and proximity labeling rather than direct in vitro assay\",\n      \"pmids\": [\"35775739\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium yoelii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"FBXO1-dependent ubiquitination interplays with CDPK1-mediated phosphorylation in P. berghei; ubiquitinomic surveys show FBXO1-dependent ubiquitination of proteins important for egress and IMC organization, with an additional layer of regulation via CDPK1 phosphorylation.\",\n      \"method\": \"Ubiquitinomics (proteomics of FBXO1-dependent ubiquitinated proteins), co-immunoprecipitation, genetic disruption of FBXO1\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — interplay between FBXO1-ubiquitination and CDPK1-phosphorylation demonstrated at proteomic level but direct mechanistic link is not fully resolved\",\n      \"pmids\": [\"36898988\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PP7 (protein phosphatase 7) interacts with CDPK1 in P. falciparum, as determined by co-immunoprecipitation, consistent with a role for CDPK1 in the calcium signaling network that PP7 participates in.\",\n      \"method\": \"Co-immunoprecipitation, conditional disruption of PP7, phosphoproteomics\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP demonstrating CDPK1-PP7 interaction; no functional consequence of the interaction directly tested\",\n      \"pmids\": [\"39387582\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PfRKIP interacts with CDPK1 within P. falciparum parasites (confirmed by immunofluorescence and proximity biotinylation); PfRKIP regulates CDPK1 kinase activity; in the presence of a substrate, CDPK1 hyper-phosphorylates PfRKIP causing its dissociation from CDPK1, thereby allowing CDPK1 to trans-phosphorylate other substrates.\",\n      \"method\": \"ELISA (in vitro binding), immunofluorescence assay (co-localization in parasites), proximity biotinylation (TurboID), in vitro kinase assay, in silico docking and mutagenesis of PEBP domain\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — interaction validated by proximity biotinylation in situ and ELISA in vitro; regulatory mechanism demonstrated by kinase assay; single lab\",\n      \"pmids\": [\"39842334\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"PF3D7_0217500 (CDPK1) is a calcium-directly-activated serine/threonine kinase whose EF-hand domain (sites I and II critical) activates the kinase domain intramolecularly via the junction domain; it is dually acylated (N-myristoylation + palmitoylation, the latter mediated by DHHC2) and membrane-targeted to the IMC/parasite plasma membrane periphery, where it phosphorylates motor complex components (MTIP-S47, GAP45 at multiple serines), PfSERA5 (promoting egress), the PKA regulatory subunit (modulating PKA activity), and likely RhopH3-S804 (regulating rhoptry secretion); CDPK1 itself is phosphorylated by PfPKG upstream, forms a Pf14-3-3I–PKA–CDPK1 multiprotein complex required for merozoite invasion, and is subject to translational repression by PfAlba1 in trophozoites; in P. falciparum it is essential for asexual blood-stage growth, microneme secretion, erythrocyte invasion, and gametogenesis, whereas in P. berghei blood and liver stages it is dispensable but required in mosquito sexual stages and for sporozoite motility.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PF3D7_0217500 (CDPK1) is a calcium-directly-activated serine/threonine protein kinase that coordinates the motility, secretory, and egress machinery driving Plasmodium erythrocyte invasion and sexual-stage development [#0, #18]. Its enzymatic activity is switched on intramolecularly: the C-terminal EF-hand/calmodulin-like domain binds Ca2+ (EF-hand sites I and II being decisive) and engages the junction domain P3 region to relieve autoinhibition and activate the kinase without calmodulin, a regulatory interface whose disruption blocks microneme discharge and invasion [#0, #1, #8]. The protein is dually acylated through an N-terminal myristoylation-plus-palmitoylation-plus-basic-cluster module that targets it to the parasite membrane periphery; palmitoylation is dynamic and, in P. yoelii, is delivered by the IMC palmitoyl-acyl-transferase DHHC2, tying membrane localization to microneme secretion and invasion [#3, #21, #26]. At its membrane location CDPK1 phosphorylates components of the glideosome actomyosin motor (MTIP at Ser47 and GAP45 at multiple serines) and the adhesin adaptor MTRAP, and phosphorylates PfSERA5 to enhance its protease activity and promote merozoite egress [#6, #7, #19, #22]. CDPK1 is embedded in a signalling network: it acts downstream of the cGMP-dependent kinase PfPKG, phosphorylates the PfPKA regulatory subunit, and assembles a phospho-dependent Pf14-3-3I–PfPKA-R complex required for microneme secretion and invasion [#15, #18, #23]. Genetic ablation confirms CDPK1 is essential for P. falciparum asexual growth, invasion, and gametogenesis, whereas in P. berghei it is dispensable in blood and liver stages and required instead for sexual mosquito-stage development and optimal sporozoite motility [#20, #13, #24, #9].\",\n  \"teleology\": [\n    {\n      \"year\": 1993,\n      \"claim\": \"Establishing that CDPK1 is a bona fide calcium-activated kinase answered whether a single polypeptide could couple Ca2+ sensing to catalysis without an accessory calmodulin.\",\n      \"evidence\": \"Recombinant full-length protein in E. coli with Ca2+-dependent in vitro kinase assay\",\n      \"pmids\": [\"8440720\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No physiological substrates identified at this stage\", \"Mechanism of intramolecular activation not resolved\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 1994,\n      \"claim\": \"Dissecting the four EF-hand motifs defined which Ca2+-binding sites drive the activating conformational change, localizing the regulatory switch to sites I and II.\",\n      \"evidence\": \"Site-directed mutagenesis of EF-hand motifs with in vitro kinase assay, CD, and 45Ca2+ binding; plus biochemical characterization of substrate preference, autophosphorylation, and membrane-fraction localization\",\n      \"pmids\": [\"8142371\", \"7808482\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of EF-hand-to-kinase coupling not defined\", \"In vitro substrates (casein, histone) not physiological targets\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Identifying the N-terminal acylation/basic-cluster module answered how a soluble kinase is anchored to membranes and directed to secretory compartments.\",\n      \"evidence\": \"N-terminal mutagenesis, GFP reporter targeting, in vitro myristoylation, and immunogold EM in P. falciparum\",\n      \"pmids\": [\"15491359\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Enzyme responsible for palmitoylation not identified here\", \"Functional consequence of membrane targeting not tested genetically\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Linking CDPK1 to the glideosome motor and demonstrating essentiality established its role in the invasion/egress machinery and validated it as a drug target.\",\n      \"evidence\": \"Failed gene disruption plus inhibitor phenotyping; in vitro phosphorylation of MTIP (Ser47) and GAP45 with MS site mapping, IFA localization, and invasion-blocking inhibitors\",\n      \"pmids\": [\"18454143\", \"18768477\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional impact of motor-component phosphorylation not directly shown\", \"Essentiality inferred from failed disruption rather than conditional knockout\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Comprehensive mapping of GAP45 phosphosites clarified the extent and regulatory logic of CDPK1 modification of a motor anchor.\",\n      \"evidence\": \"In vitro phosphorylation with nano-UPLC-MS/MS, IMAC enrichment, and synthetic phosphopeptide controls\",\n      \"pmids\": [\"19549500\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological occupancy of these sites in parasites not established\", \"Functional readout of individual sites absent\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Defining the CamLD–junction domain P3 interaction resolved the structural mechanism of intramolecular autoinhibition and provided a peptide tool that blocks invasion.\",\n      \"evidence\": \"Junction-domain mutagenesis, CamLD–JD binding assay, P3 peptide inhibition, microneme and invasion assays; plus autophosphorylation/NTE mapping and GFP-localization/J-domain knockdown\",\n      \"pmids\": [\"23204525\", \"22539638\", \"23548171\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full activated-state structure not solved\", \"NTE ATP-binding site partly modeling-dependent\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Genetic work in P. berghei revealed a stage-restricted essentiality and an unexpected role for CDPK1 as a translational activator in the developing zygote.\",\n      \"evidence\": \"Conditional knockdown in P. berghei sexual stages with ribosome footprinting, transcriptional profiling, and mosquito infection assays\",\n      \"pmids\": [\"22817984\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism by which CDPK1 activates translation unknown\", \"Direct RNA/ribosome targets of CDPK1 not defined\"],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"A clean P. berghei conditional knockout established species-divergent essentiality: dispensable in blood and liver stages, essential only in mosquito sexual stages.\",\n      \"evidence\": \"Homologous-recombination disruption and conditional knockout with stage-specific phenotyping in P. berghei\",\n      \"pmids\": [\"24265753\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Basis for divergence from P. falciparum essentiality not explained\", \"Redundant kinases masking blood-stage phenotype not identified\"],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Heterologous rescue of a T. gondii CDPK mutant demonstrated that CDPK1 function requires both membrane localization and kinase activity, and built a surrogate for inhibitor validation.\",\n      \"evidence\": \"Complementation of T. gondii TgCDPK3 mutant with membrane/kinase-dead mutagenesis and egress assays\",\n      \"pmids\": [\"24550330\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Native P. falciparum substrates driving egress in this assay not defined\", \"Cross-species functional equivalence limits mechanistic inference\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Placing CDPK1 downstream of PfPKG and mapping PfAlba1 repression of CDPK1 mRNA situated the kinase within phospho- and translational-control cascades governing egress/invasion.\",\n      \"evidence\": \"Quantitative phosphoproteomics with PKG chemical/genetic perturbation; RIP-seq of PfAlba1-bound CDPK1 mRNA with translation-state analysis\",\n      \"pmids\": [\"26149123\", \"26415947\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"PfPKG phosphosite(s) on CDPK1 and their functional consequence not defined\", \"Direct effect of PfAlba1 release on CDPK1 protein levels only correlative\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Gatekeeper mutation studies exposed pathway compensation, showing PKG-linked activity buffers reduced CDPK1 function.\",\n      \"evidence\": \"CRISPR/Cas9 T145M substitution with bumped-kinase and PKG inhibitor epistasis and RNA-seq of CDPK5/CDPK6\",\n      \"pmids\": [\"27923926\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Compensating kinase not directly demonstrated\", \"Transcript upregulation not shown to restore function\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Conditional knockdown plus comparative phosphoproteomics confirmed the invasion requirement and revealed CDPK1–PKA crosstalk via phosphorylation of the PKA regulatory subunit.\",\n      \"evidence\": \"Inducible knockdown, comparative phosphoproteomics, in vitro kinase assay, and invasion assay in P. falciparum\",\n      \"pmids\": [\"28680058\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional output of PfPKA-R phosphorylation on invasion not fully dissected\", \"Which substrates are direct versus indirect remains partly open\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Definitive P. falciparum disruption (only tolerated on a low-activity background) and complementation quantified requirements across asexual growth and gametogenesis; PfSERA5 was defined as an egress-promoting substrate.\",\n      \"evidence\": \"CRISPR/Cas9 disruption with complementation and RNA-seq; co-IP/co-sedimentation/co-immunolocalization of PfSERA5 with in vitro phosphorylation and egress assays\",\n      \"pmids\": [\"29311293\", \"29716996\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism coupling CDPK1 loss to elevated gametocyte transcripts unclear\", \"PfSERA5 phosphosite(s) not mapped\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Multiple 2020 studies integrated CDPK1 into a membrane-anchored signalling hub—dynamic palmitoylation, MTRAP phosphorylation, a 14-3-3I/PKA-R complex, and RhopH3-linked rhoptry discharge—while P. berghei work defined a sporozoite-motility role.\",\n      \"evidence\": \"ABE/CuAAC palmitoylation imaging with PAT inhibitor and invasion assays; in vitro MTRAP-CTD phosphorylation/aldolase binding; phosphoproteomics, reciprocal co-IP, gel filtration, SPR and phosphopeptide competition for the Pf14-3-3I–PKA-R complex; RhopH3-S804 phosphomutant with CDPK1 knockdown; P. berghei cKO with cGMP epistasis\",\n      \"pmids\": [\"32003970\", \"27607074\", \"32817103\", \"32484216\", \"33024030\", \"32866196\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological MTRAP phosphorylation by CDPK1 not detected in tagged parasites\", \"Direct phosphorylation of RhopH3-S804 by CDPK1 not shown in vitro\", \"PAT inhibitor used is not CDPK1-specific\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}, {\"species\": \"Plasmodium yoelii\", \"strain\": \"\"}, {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identifying DHHC2 as the IMC palmitoyl-acyl-transferase acting on CDPK1 connected the acylation-dependent localization to a specific enzyme and to schizont segmentation.\",\n      \"evidence\": \"TurboID IMC proteomics, palmitome cross-referencing, and conditional DHHC2 depletion with CDPK1 localization in P. yoelii\",\n      \"pmids\": [\"35775739\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct in vitro palmitoylation of CDPK1 by DHHC2 not demonstrated\", \"Species-specific relevance to P. falciparum not tested\"],\n      \"attribution\": [{\"species\": \"Plasmodium yoelii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Characterizing the PfRKIP–CDPK1 relationship in parasites established a substrate-dependent regulatory loop in which hyperphosphorylation releases PfRKIP to permit trans-phosphorylation of other substrates.\",\n      \"evidence\": \"ELISA binding, IFA co-localization, TurboID proximity biotinylation, in vitro kinase assay, and PEBP-domain docking/mutagenesis in P. falciparum (building on earlier in vitro identification of PfRKIP as substrate/regulator)\",\n      \"pmids\": [\"39842334\", \"17123645\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo consequence of PfRKIP regulation on invasion/egress not established\", \"Single-lab regulatory model\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CDPK1 phosphorylation events are spatiotemporally integrated with dephosphorylation and ubiquitination during the invasion/egress cycle remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Functional consequence of the CDPK1–PP7 interaction untested\", \"Direct mechanistic link between FBXO1-dependent ubiquitination and CDPK1 phosphorylation not resolved\", \"Ordering of substrate phosphorylation events during a single invasion cycle unknown\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}, {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004674\", \"supporting_discovery_ids\": [0, 2, 6, 7, 18, 19]},\n      {\"term_id\": \"GO:0005509\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"GO:0009931\", \"supporting_discovery_ids\": [0, 1, 8]},\n      {\"term_id\": \"GO:0046872\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0020002\", \"supporting_discovery_ids\": [6, 10, 21]},\n      {\"term_id\": \"GO:0020008\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [10, 21]},\n      {\"term_id\": \"GO:0032993\", \"supporting_discovery_ids\": [2, 3, 26]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0044409\", \"supporting_discovery_ids\": [5, 6, 18, 20, 24]},\n      {\"term_id\": \"GO:0019722\", \"supporting_discovery_ids\": [15, 17, 24, 28]},\n      {\"term_id\": \"GO:0006935\", \"supporting_discovery_ids\": [6, 22, 24]}\n    ],\n    \"complexes\": [\n      \"Pf14-3-3I–PfPKA-R–CDPK1 phospho-dependent multiprotein complex [#23]\"\n    ],\n    \"partners\": [\n      \"PfSERA5 (interactor and substrate) [#19]\",\n      \"Pf14-3-3I (binds phospho-CDPK1) [#23]\",\n      \"PfPKA-R (substrate/complex member) [#18, #23]\",\n      \"PfPKG (upstream kinase) [#15]\",\n      \"PfAlba1 (RNA-binding repressor of CDPK1 mRNA) [#16]\",\n      \"PfRKIP/PfPE-PB1 (substrate and regulator) [#4, #29]\",\n      \"PP7 protein phosphatase (co-IP) [#28]\",\n      \"DHHC2 palmitoyl-acyl-transferase [#26]\"\n    ],\n    \"other_free_text\": [\n      \"Substrates/phosphotargets: MTIP (Ser47), GAP45 (multiple serines), MTRAP cytoplasmic tail, PfSERA5, PfPKA-R, and candidate RhopH3-Ser804 [#6, #7, #11, #22, #18, #19, #25]\",\n      \"Activity requires Ca2+-dependent CamLD–junction domain (P3) intramolecular interaction; EF-hand sites I and II are decisive [#1, #8]\",\n      \"Membrane targeting via N-terminal myristoylation + palmitoylation + basic cluster; palmitoylation is dynamic [#3, #21]\",\n      \"Species divergence: essential in P. falciparum asexual growth/invasion/gametogenesis; dispensable in P. berghei blood/liver stages but required for mosquito sexual stages and sporozoite motility [#20, #13, #24, #9]\",\n      \"FBXO1-dependent ubiquitination interplays with CDPK1 phosphorylation in P. berghei egress/IMC regulation (Low confidence) [#27]\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_0217500","name":null,"product":"calcium-dependent protein kinase 1","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_0314200","name":null,"product":"calcium-dependent protein kinase 1","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_0403400","name":null,"product":"calcium-dependent protein kinase 1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"CDPK1","evaluation":null}