Affinage · Plasmodium

PF3D7_1423600

calcium-dependent protein kinase, putative

Annotated
2026-09-08
68 papers in source corpus 26 papers cited in narrative 25 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

PfCDPK1 (PF3D7_1423600) is a plant-like calcium-dependent protein kinase that couples Ca2+ signaling to the invasion and egress machinery of the malaria parasite, comprising an N-terminal kinase domain and a C-terminal calmodulin-like regulatory domain bearing four EF-hand motifs (PMID:8440720). Ca2+ binding (K0.5 ~15 µM) activates the enzyme, with EF-hand sites I and II being critical for the conformational change and catalytic activation while sites III and IV contribute minimally (PMID:8142371, PMID:7808482); activation additionally depends on the N-terminal extension and on autophosphorylation at sites positioned for kinase activation (PMID:22539638), and on Ca2+-dependent engagement of the junction (J) domain P3 region by the calmodulin-like domain, since P3 peptides or J-domain hydrophobic mutations abrogate activity, block microneme discharge, and block erythrocyte invasion (PMID:23204525). The kinase is targeted to parasite membranes—including the parasitophorous vacuole, tubovesicular system, and merozoite periphery/inner membrane complex—through dual acylation (myristoylation plus palmitoylation) and a basic cluster, with dynamic palmitoylation regulating membrane association during invasion (PMID:15491359, PMID:18768477, PMID:32003970). Functionally, PfCDPK1 phosphorylates glideosome/motor components MTIP and GAP45 (PMID:18768477, PMID:19549500), the egress protease PfSERA5 (which it also binds and activates) (PMID:29716996), and the PKA regulatory subunit PfPKA-R, thereby linking Ca2+/CDPK1 to cAMP/PKA signaling (PMID:28680058); it sits downstream of PfPKG in the cGMP cascade (PMID:26149123) and assembles into a phosphorylation-dependent Pf14-3-3I-scaffolded multiprotein signaling complex whose disruption blocks microneme secretion and invasion (PMID:32817103, PMID:32484216). In asexual blood stages of P. falciparum the kinase is essential/critical for merozoite egress and erythrocyte invasion (PMID:18454143, PMID:28680058), whereas in P. berghei CDPK1 is dispensable for erythrocytic and pre-erythrocytic development and is instead essential in the mosquito sexual stages, where it translationally activates repressed zygote mRNAs (PMID:22817984, PMID:24265753).

Mechanistic history

Synthesis pass · year-by-year structured walk · 18 steps
  1. 1993 High

    Establishing what class of enzyme this gene encodes was the first requirement; cloning and reconstitution showed it is a plant-like CDPK with an intramolecular Ca2+ sensor rather than a canonical kinase requiring separate calmodulin.

    Evidence Molecular cloning, recombinant expression in E. coli, and in vitro Ca2+-dependent kinase assay

    PMID:8440720

    Open questions at the time
    • Physiological substrates not identified
    • In vivo localization and stage expression not yet defined
  2. 1994 High

    How Ca2+ actually activates the kinase was resolved by dissecting the four EF-hands, showing that sites I and II drive the activating conformational change while III and IV are minor—defining the regulatory logic of the sensor domain.

    Evidence Site-directed mutagenesis of EF-hand motifs with circular dichroism, 45Ca2+ binding, autophosphorylation, and in vitro kinase assays; substrate preference for casein and histone H1

    PMID:7808482 PMID:8142371

    Open questions at the time
    • Casein/histone are generic in vitro substrates, not physiological targets
    • Mechanism linking Ca2+ binding to catalytic activation not resolved at structural level
  3. 1994 Medium

    Whether the kinase acts on host or parasite proteins and where it resides was addressed by fractionation and in vitro substrate profiling, pointing to membrane-organelle localization and possible host erythrocyte membrane targets.

    Evidence In vitro kinase assay with erythrocyte membrane proteins, calmodulin antagonist inhibition, immunoblotting, and subcellular fractionation

    PMID:7808482

    Open questions at the time
    • Host membrane phosphorylation not confirmed in vivo
    • Fractionation localization lacks organelle-level resolution
  4. 2004 High

    How a soluble kinase reaches its site of action was answered by identifying dual acylation plus a basic motif as the membrane-targeting determinant directing PfCDPK1 to the parasitophorous vacuole and tubovesicular system.

    Evidence Immunogold EM, GFP acylation-mutant localization, and in vitro myristoylation assay

    PMID:15491359

    Open questions at the time
    • Palmitoyl transferase responsible not identified here
    • Functional consequence of mistargeting on kinase activity not tested
  5. 2004 Medium

    The biophysical basis of Ca2+ sensitivity was quantified by showing the regulatory domain has a high-affinity C-lobe and weaker N-lobe, with the junction region tuning affinity, refining the model of autoinhibition release.

    Evidence NMR, Ca2+ titration, and CD on isolated J-CaM-LD constructs

    PMID:15126505

    Open questions at the time
    • Model built on isolated domain, not intact kinase
    • Single-lab biophysical study
  6. 2008 High

    The physiological substrate question was answered by identifying glideosome motor components MTIP and GAP45 as targets, connecting the kinase to the invasion motor, alongside genetic and chemical evidence for essentiality.

    Evidence In vitro kinase assays with MS phosphosite mapping, immunofluorescence, K252a/purine inhibitor treatment, and targeted disruption attempt

    PMID:18454143 PMID:18768477

    Open questions at the time
    • Functional consequence of MTIP/GAP45 phosphorylation on motor activity not defined
    • Gene-disruption essentiality inferred from failed knockout
  7. 2009 High

    The extent and consequence of GAP45 phosphorylation was mapped, revealing nine sites and demonstrating that phosphorylation alters GAP45's protease-accessibility, hinting at a structural regulatory effect.

    Evidence In vitro kinase assay, multi-protease digestion, IMAC enrichment, and nano-UPLC-MS/MS

    PMID:19549500

    Open questions at the time
    • In vivo occupancy of these nine sites unknown
    • Biological readout of altered protease sensitivity untested
  8. 2012 High

    Species-divergent roles emerged: in P. berghei CDPK1 is dispensable in blood/pre-erythrocytic stages but essential in mosquito sexual stages, where it was shown to translationally activate mRNAs repressed in the macrogamete.

    Evidence Conditional knockdown with polysome/translational and transcriptional profiling and mosquito transmission assays in P. berghei

    PMID:22817984 PMID:24265753

    Open questions at the time
    • Molecular mechanism of translational activation (direct targets) not defined
    • Whether P. falciparum CDPK1 shares this sexual-stage function untested
  9. 2012 Medium

    Whether GAP45 phosphorylation controls motor assembly was tested and answered negatively—phosphosite mutants assembled and localized normally—refocusing GAP45 phosphorylation's role away from assembly.

    Evidence GFP-tagging, phosphoserine-to-Ala/Asp mutagenesis, immunofluorescence, co-IP, and PLC-pathway/PfPKB comparisons

    PMID:22479457 PMID:22558243

    Open questions at the time
    • Actual function of GAP45 phosphorylation remains unresolved
    • Overlap with PfPKB activity complicates attribution to CDPK1 in vivo
  10. 2012 High

    The activation mechanism was refined by showing Ca2+-dependent CaM-LD binding to the J-domain P3 region drives activity, and that blocking this interaction pharmacologically stops microneme discharge and invasion—linking the activation switch to a druggable functional output.

    Evidence Peptide binding assays, J-domain mutagenesis, kinase assay, microneme secretion and invasion assays, purfalcamine/P3-peptide inhibition; MS mapping of autophosphorylation and NTE ATP-binding site

    PMID:22539638 PMID:23204525

    Open questions at the time
    • Structural basis of NTE ATP-binding site unresolved
    • Whether P3-region interaction is regulated in vivo not shown
  11. 2014 Medium

    Functional conservation and druggability were tested by heterologous complementation in Toxoplasma, showing PfCDPK1 rescues an egress defect only when membrane-localized and catalytically active, and that its activity is selectively inhibitable.

    Evidence Complementation in T. gondii TgCDPK3-null parasites, gatekeeper/membrane-motif mutagenesis, egress and drug-sensitivity assays

    PMID:24550330

    Open questions at the time
    • Rescue in a heterologous system may not reflect native P. falciparum egress role
    • Direct egress substrates in T. gondii context not identified
  12. 2015 Medium

    The upstream regulator was placed by phosphoproteomics identifying PfCDPK1 as a PfPKG target, positioning it downstream of PfPKG in the cGMP cascade controlling egress and invasion.

    Evidence Quantitative global phosphoproteomics with chemical and genetic PfPKG inhibition

    PMID:26149123

    Open questions at the time
    • Direct versus indirect phosphorylation by PfPKG not distinguished
    • Functional consequence of PKG-dependent phosphosites on CDPK1 untested
  13. 2016 High

    Conditional knockdown established PfCDPK1 as critical for P. falciparum invasion and, via phosphoproteomics, expanded its substrate set to IMC/motor proteins and PfPKA-R, revealing Ca2+/CDPK1–cAMP/PKA cross-talk.

    Evidence Conditional knockdown, comparative phosphoproteomics, in vitro kinase assay, PKA activity assay; CRISPR T145M gatekeeper mutant with compensatory kinase upregulation

    PMID:27923926 PMID:28680058

    Open questions at the time
    • Compensation by PKG/CDPK5/CDPK6 complicates loss-of-function interpretation
    • Which invasion phenotypes are direct CDPK1 effects not fully separated
  14. 2018 High

    A direct egress substrate was defined by showing PfCDPK1 binds and Ca2+-dependently phosphorylates PfSERA5, enhancing its protease activity, and that inhibiting this blocks merozoite egress.

    Evidence IP-MS, co-sedimentation, reciprocal co-IP, co-immunolocalization, in vitro kinase assay, purfalcamine treatment, and egress assay

    PMID:29716996

    Open questions at the time
    • In vivo requirement of the specific phosphosites for egress not genetically confirmed
  15. 2020 High

    How CDPK1 is organized into a signaling hub and how membrane engagement is dynamically controlled were addressed: Pf14-3-3I binds phospho-CDPK1 at a Mode-I motif to scaffold a multiprotein complex, and dynamic palmitoylation controls merozoite membrane localization, both required for microneme secretion and invasion.

    Evidence Co-IP, gel filtration, ELISA, SPR/ITC, MD simulation for 14-3-3I; acyl biotin exchange, CuAAC imaging, and 2-bromopalmitate treatment for palmitoylation

    PMID:32003970 PMID:32484216 PMID:32817103

    Open questions at the time
    • Full composition of the 14-3-3I-scaffolded complex not defined
    • Identity of the palmitoyl acyltransferase acting on CDPK1 unknown
  16. 2006 Low

    A candidate regulator was proposed by showing PfRKIP is a weak substrate that boosts CDPK1 autophosphorylation while dampening substrate phosphorylation, hinting at feedback modulation.

    Evidence Recombinant in vitro kinase and autophosphorylation assays

    PMID:17123645

    Open questions at the time
    • Single in vitro assay without in vivo validation of the regulatory interaction
    • Physiological relevance of RKIP modulation unknown
  17. 2022 Low

    A structural hypothesis for activation was generated computationally, proposing the CAD allosterically stabilizes the kinase active conformation via an αC–β3 salt bridge.

    Evidence Microsecond-scale MD simulation of modeled PfCDPK1 with and without the CAD

    PMID:35709874

    Open questions at the time
    • Purely computational, no experimental or structural validation
    • Salt-bridge mechanism not tested by mutagenesis in the intact kinase
  18. 2024 Low

    New potential regulatory links were reported: a Ca2+-dependent phosphatase PP7 co-IPs with PfCDPK1, and in P. berghei FBXO1-dependent ubiquitination shows interplay with CDPK1-dependent phosphorylation in egress/IMC processes.

    Evidence Co-immunoprecipitation for PP7; ubiquitinomic profiling with FBXO1 deletion in P. berghei

    PMID:36898988 PMID:39387582

    Open questions at the time
    • Single co-IP for PP7 without functional characterization on the CDPK1 side
    • FBXO1–CDPK1 mechanistic relationship not directly demonstrated for PF3D7_1423600

Open questions

Synthesis pass · forward-looking unresolved questions
  • The structural mechanism coupling Ca2+ binding to catalytic activation in the intact kinase, and the in vivo phosphosite requirements distinguishing which of CDPK1's many substrates are functionally essential for egress versus invasion, remain unresolved.
  • No experimental full-length structure of active/inactive states
  • Substrate-specific genetic dissection of egress versus invasion roles incomplete
  • Species divergence between P. falciparum (blood-stage essential) and P. berghei (sexual-stage essential) not mechanistically reconciled

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
GAP45 (SUBSTRATE) [#5, #7, #9, #12]MTIP (SUBSTRATE) [#5]PF14-3-3I (PHOSPHO-DEPENDENT SCAFFOLD) [#20]PFPKA-R / PFPKA (SUBSTRATE AND REGULATORY CROSS-TALK) [#16]PFPKG (UPSTREAM KINASE) [#15]PFRKIP/PFPE-PB1 (WEAK SUBSTRATE/CANDIDATE REGULATOR) [#19]PFSERA5 (BINDING PARTNER AND SUBSTRATE) [#18]PP7 PHOSPHATASE (CO-IP INTERACTOR) [#23]
Complex memberships
Glideosome/actomyosin motor complex (via GAP45/MTIP substrates) [#5, #7, #9]Pf14-3-3I-scaffolded multiprotein signaling complex (phosphorylation-dependent) [#20]

Evidence

Reading pass · 25 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1993 PfCDPK1 (PfCPK) was identified as a calcium-dependent protein kinase with an N-terminal kinase domain and C-terminal EF-hand calcium-binding domain (four EF-hand motifs). Recombinant protein expressed in E. coli exhibited Ca2+-dependent protein kinase activity, establishing it as a plant-like CDPK. Molecular cloning, sequence analysis, recombinant expression in E. coli, in vitro kinase assay The Journal of biological chemistry High 8440720
1994 PfCDPK1 has four EF-hand calcium-binding sites in its C-terminal domain. EF-hand sites I and II are crucial for both Ca2+-induced conformational change and enzymatic activation; site II mutations almost completely abolish kinase activity, site I mutations dramatically reduce Ca2+-sensitivity and activation. Sites III and IV have minor effects. The kinase is activated by Ca2+ (K0.5 = 15 µM) and undergoes autophosphorylation on serine and threonine residues. It preferentially phosphorylates casein and histone H1 in vitro. Site-directed mutagenesis of EF-hand motifs (Glu→Lys or Glu→Gln), circular dichroism, in vitro kinase assay, 45Ca2+ binding, autophosphorylation assay Biochemistry High 7808482 8142371
1994 Purified recombinant PfCDPK1 preferentially phosphorylates proteins of the host erythrocytic membrane in vitro but phosphorylates parasitic proteins only to a minor extent. Calmodulin antagonists (calmidazolium, trifluoperazine, W-7, ophiobolin A) inhibit kinase activation at higher concentrations than needed to inhibit calmodulin-mediated effects. The kinase is mainly expressed in ring and schizont stages and localizes predominantly to the parasitic membrane-organelle fraction and partially to the erythrocytic membrane. In vitro kinase assay with erythrocytic membrane proteins, calmodulin antagonist inhibition assay, immunoblotting with polyclonal antiserum, subcellular fractionation Molecular and biochemical parasitology Medium 7808482
2004 PfCDPK1 contains three N-terminal membrane-anchoring motifs: a myristoylation consensus sequence, a putative palmitoylation site, and a basic motif. The kinase is myristoylated both in vivo (endogenous) and in vitro. Dual acylation (myristoylation + palmitoylation) together with the basic cluster are required for correct targeting of PfCDPK1 to the parasitophorous vacuole and the tubovesicular system, as shown by immunogold electron microscopy and GFP mutagenesis experiments. Immunogold electron microscopy, GFP fusion mutagenesis (acylation site mutants), in vitro myristoylation assay, subcellular targeting experiments Molecular microbiology High 15491359
2004 The calmodulin-like domain (CaM-LD) of a Plasmodium CDPK (studied using spectroscopic/biophysical methods applicable to PfCDPK1 regulatory domain) is composed of two lobes with differing Ca2+ affinities: the C-lobe has two cooperatively interacting high-affinity sites (Kd ~5.6 nM) and the N-lobe has two weaker sites (Kd ~110 nM). The junction (J) region has an essential role in stabilizing the CaM-LD structure and dramatically increases Ca2+ affinity. A model is supported whereby the C-lobe interacts with the junction even at basal Ca2+ but kinase remains autoinhibited until the N-lobe weaker sites are filled. NMR spectroscopy, Ca2+ titration/binding measurements, circular dichroism, domain-construct analysis of isolated J-CaM-LD The Journal of biological chemistry Medium 15126505
2008 PfCDPK1 phosphorylates two components of the parasite motor complex (glideosome): myosin A tail domain-interacting protein (MTIP) at serine 47, and glideosome-associated protein 45 (GAP45) at two sites (one confirmed in parasite phosphopeptides). PfCDPK1 localizes to the periphery of P. falciparum merozoites by indirect immunofluorescence, consistent with its acting on MTIP and GAP45 at the inner membrane complex. Both PfCDPK1 activity and host cell invasion are inhibited by the kinase inhibitor K252a. In vitro kinase assay, indirect immunofluorescence, mass spectrometry-based phosphopeptide identification from parasite lysates, kinase inhibitor treatment The Journal of biological chemistry High 18768477
2008 PfCDPK1 is coexpressed with genes encoding the parasite motor complex. A targeted gene-disruption approach showed that pfcdpk1 appears essential for parasite viability in the erythrocytic stage, and treatment with 2,6,9-trisubstituted purine inhibitors of PfCDPK1 caused sudden developmental arrest at the late schizont stage in P. falciparum, suggesting a role in motility regulation during egress/invasion. Targeted gene disruption attempt, gene expression profiling, in vitro biochemical screen, compound treatment phenotypic assay Nature chemical biology Medium 18454143
2009 PfCDPK1 phosphorylates PfGAP45 at nine sites in vitro (Ser31, Ser89, Ser103, Ser109, Ser121, Ser149, Ser156, Thr158, Ser173) as identified by mass spectrometry after multi-protease digestion. Phosphorylation at adjacent sites Ser156 and Thr158 is mutually exclusive, and phosphorylation at these sites interferes specifically with proteolytic cleavage by chymotrypsin or trypsin respectively, demonstrating that phosphorylation alters the kinase substrate and protease substrate properties of GAP45. In vitro kinase assay (PfCDPK1 + PfGAP45), multi-protease digestion, Ga(III)-IMAC phosphopeptide enrichment, nano-UPLC-ESI-MS/MS Analytical biochemistry High 19549500
2012 In P. berghei, CDPK1 is expressed in all life stages and is indispensable during sexual mosquito stages. Knockdown of CDPK1 in sexual stages arrested zygote development and prevented mosquito transmission. Translational and transcriptional profiling of arrested parasites revealed that CDPK1 translationally activates mRNA species in the developing zygote that remain repressed (via 3' and 5' UTRs) in macrogametes, establishing a role for CDPK1 in translational activation of repressed mRNAs. Conditional knockdown, translational profiling (polysome analysis), transcriptional profiling, mosquito transmission assays Cell host & microbe High 22817984
2012 PfCDPK1 phosphorylates GAP45 in P. falciparum schizonts at specific serine residues. GAP45 is assembled early into the motor complex and transported to the developing inner membrane complex. Replacing phosphorylated serines with alanine or aspartate has no apparent effect on GAP45 assembly into the motor protein complex or its subcellular location, indicating phosphorylation by PfCDPK1 at these sites is not required for GAP45 assembly. GFP-tagging of GAP45 (internal), site-directed mutagenesis of phosphoserine residues, immunofluorescence, co-immunoprecipitation, in vitro phosphorylation PloS one Medium 22479457
2012 PfCDPK1 directly regulates the junction (J) domain: binding of the calmodulin-like domain (CaM-LD) to the P3 region (Leu356–Thr370) of the J domain occurs in a Ca2+-dependent manner. Site-directed mutagenesis of conserved hydrophobic residues in the J domain (F363A/I364A, L356A, F350A) abrogates PfCDPK1 functional activity. A P3 peptide specifically inhibits PfCDPK1 activity and blocks microneme discharge and erythrocyte invasion by P. falciparum merozoites. The PfCDPK1 inhibitor purfalcamine also blocks microneme discharge and erythrocyte invasion. In vitro binding assay (CaM-LD + J domain peptides), site-directed mutagenesis, in vitro kinase assay, microneme secretion assay, erythrocyte invasion assay, peptide inhibitor treatment The Journal of biological chemistry High 23204525
2012 PfCDPK1 autophosphorylates at multiple sites as detected by mass spectrometry, and some of these autophosphorylation sites are at strategic locations critical for kinase activation. The N-terminal extension (NTE) of PfCDPK1 is important for its activation, and unexpectedly an ATP-binding site was identified within the NTE. Mass spectrometry (autophosphorylation site identification), molecular modeling, site-directed mutagenesis, in vitro kinase assay FASEB journal Medium 22539638
2012 PfGAP45 is phosphorylated by PfCDPK1 at S89, S103, and S149 in response to phospholipase C and calcium signaling. PfPKB also phosphorylates GAP45 at the same sites. The phospholipase C pathway influences phosphorylation at S103 and S149. Phosphorylation of GAP45 at these sites is differentially regulated during parasite development but does not affect GAP45 localization or its association with the glideosome complex. In vitro kinase assay, phosphosite-specific mutagenesis, co-immunoprecipitation, immunofluorescence, PLC pathway inhibition PloS one Medium 22558243
2013 P. berghei CDPK1 is dispensable for erythrocytic stage invasion and intra-erythrocytic development, as well as for sporozoite invasion of hepatocytes, egress from hepatocytes, and the subsequent erythrocytic cycle. Targeted gene disruption of PbCDPK1 yielded viable erythrocytic-stage parasites; a conditional mutant confirmed CDPK1 is dispensable in pre-erythrocytic stages. PbCDPK1 plays an essential role only in mosquito sexual stages. Targeted gene disruption by homologous recombination, conditional knockdown, phenotypic assays (invasion, development, transmission) PloS one Medium 24265753
2014 PfCDPK1 expressed in Toxoplasma gondii TgCDPK3-null parasites rescues the egress defect, and this rescue requires both plasma membrane localization of PfCDPK1 and its kinase activity. PfCDPK1-expressing T. gondii shows increased sensitivity to purfalcamine (a PfCDPK1-specific inhibitor). Six of eight tested PfCDPK1 inhibitors selectively inhibited ionophore-induced egress in PfCDPK1-expressing strains, and gatekeeper residue determines selectivity of dasatinib and PLX-4720. Heterologous complementation in T. gondii, mutagenesis of gatekeeper residue and membrane-targeting motif, egress assay, drug sensitivity assay Antimicrobial agents and chemotherapy Medium 24550330
2015 PfCDPK1 is phosphorylated by PfPKG, as identified by quantitative global phosphoproteomics using chemical and genetic tools to inhibit PfPKG. This places PfCDPK1 downstream of PfPKG in the cGMP signaling cascade regulating parasite egress and invasion. Quantitative global phosphoproteomics, chemical inhibition of PfPKG, genetic tools (PfPKG-null parasites) Nature communications Medium 26149123
2016 PfCDPK1 is critical for erythrocyte invasion by P. falciparum merozoites, established by conditional knockdown. Comparative phosphoproteomics identified substrates of PfCDPK1 including proteins of the Inner Membrane Complex and glideosome-actomyosin motor assembly. PfCDPK1 phosphorylates PfPKA regulatory subunit (PfPKA-R) and regulates PfPKA activity, indicating cross-talk between Ca2+/CDPK1 and cAMP/PKA signaling pathways relevant to invasion. Conditional knockdown, comparative phosphoproteomics, in vitro kinase assay, PKA activity assay Nature communications High 28680058
2016 Introduction of a methionine gatekeeper substitution (T145M) in PfCDPK1 by CRISPR/Cas9 reduced transphosphorylation activity by 47%. In mutant parasites, reduced CDPK1 activity is compensated through the action of PKG (or a kinase under PKG regulation), as T145M parasites showed increased sensitivity to the PKG inhibitor compound 2. Transcript levels of CDPK5 and CDPK6 were significantly upregulated in T145M parasites, suggesting compensatory kinase upregulation. CRISPR/Cas9 genome editing, in vitro kinase assay, compound sensitivity assay (BKI-1294, compound 2), qRT-PCR mBio Medium 27923926
2018 PfCDPK1 physically interacts with and phosphorylates PfSERA5 (serine repeat antigen 5) in vitro in a Ca2+-dependent manner, enhancing its proteolytic activity. This interaction was confirmed by co-sedimentation, co-immunoprecipitation, and co-immunolocalization. A PfCDPK1 inhibitor (purfalcamine) blocked phosphorylation and activation of PfSERA5 in vitro and in schizonts, blocking merozoite egress, identifying PfSERA5 as a functional substrate of PfCDPK1 in the egress pathway. Immunoprecipitation + MS (identification of interaction), co-sedimentation, co-immunoprecipitation, co-immunolocalization, in vitro kinase assay, purfalcamine inhibitor treatment, egress assay The Journal of biological chemistry High 29716996
2006 The Plasmodium falciparum Raf kinase inhibitory protein ortholog (PfPE-PB1/PfRKIP) is phosphorylated by PfCDPK1 in vitro (though with ~7-fold lower specific activity than casein). The presence of PfRKIP in kinase assays greatly enhanced PfCDPK1 autophosphorylation (~5.5-fold) while diminishing substrate (casein) phosphorylation activity, suggesting PfRKIP acts as a regulator of PfCDPK1. Recombinant protein expression, in vitro kinase assay, autophosphorylation assay Molecular and biochemical parasitology Low 17123645
2020 Pf14-3-3I binds phosphorylated PfCDPK1 (via phosphorylation at the canonical Mode I-type motif 61KLGpS64) to mediate assembly of a multiprotein signaling complex in P. falciparum merozoites. This interaction was validated by co-immunoprecipitation, gel filtration chromatography, ELISA, surface plasmon resonance (binding affinity ~670 nM), and molecular dynamics simulation. The 14-3-3I/CDPK1 interaction is phosphorylation-dependent and marginally enhances CDPK1 functional activity. Disruption of the multiprotein complex (using a phospho-peptide derived from PKAr) inhibits microneme secretion and RBC invasion. Co-immunoprecipitation, gel filtration chromatography, quantitative phosphoproteomics, ELISA, surface plasmon resonance (SPR), isothermal titration calorimetry (ITC), molecular dynamics simulation, in vitro kinase assay, invasion/secretion assays mBio / The Biochemical journal High 32484216 32817103
2020 PfCDPK1 undergoes dynamic palmitoylation and localizes to the merozoite membrane in a palmitoylation-dependent manner, as demonstrated by acyl biotin exchange chemistry (ABE) and confocal imaging. Exposure of merozoites to low [K+] activates palmitoyl acyl transferase (PAT) activity, and PAT inhibition by 2-bromopalmitate blocks microneme secretion and RBC invasion, implicating dynamic palmitoylation of PfCDPK1 in regulation of its membrane association and function. Acyl biotin exchange (ABE) chemistry, copper-catalyzed alkyne-azide cycloaddition (CuAAC) imaging, confocal microscopy, PAT inhibitor treatment (2-bromopalmitate), microneme secretion and invasion assays ACS infectious diseases Medium 32003970
2022 In the absence of the CAD (calmodulin-like activation domain), the salt bridge between Glu116 (αC-helix) and Lys85 (β3-sheet) of the PfCDPK1 kinase domain breaks after 200 ns of MD simulation, resulting in an inactive kinase conformation. In the complete protein (with CAD), the salt bridge remains intact, revealing that the CAD domain allosterically stabilizes the active conformation of the kinase domain. This represents a novel CAD-mediated allosteric activation mechanism. Microsecond-scale molecular dynamics (MD) simulation of modeled PfCDPK1 structures (complete protein vs. kinase domain alone), in silico screening International journal of biological macromolecules Low 35709874
2024 PP7 (a Ca2+-dependent phosphatase) physically interacts with PfCDPK1, as identified by co-immunoprecipitation/interaction studies, consistent with a role for both proteins in calcium signaling pathways during blood-stage development. Co-immunoprecipitation (interaction identified in the context of PP7 function studies) mBio Low 39387582
2023 In P. berghei, SCFFBXO1-dependent ubiquitination and CDPK1-dependent phosphorylation show functional interplay: ubiquitinomic surveys identified FBXO1-dependent ubiquitination of proteins important for egress and IMC organization that overlap with CDPK1-regulated processes, and the study demonstrates an interplay between FBXO1-dependent ubiquitination and phosphorylation via CDPK1. Ubiquitinomic profiling (mass spectrometry), genetic deletion of FBXO1, phenotypic assays Nature communications Low 36898988

Source papers

Stage 0 corpus · 68 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2004 Protein kinases of the human malaria parasite Plasmodium falciparum: the kinome of a divergent eukaryote. BMC genomics 416 15479470
2004 Calcium and a calcium-dependent protein kinase regulate gamete formation and mosquito transmission in a malaria parasite. Cell 365 15137943
2010 A plant-like kinase in Plasmodium falciparum regulates parasite egress from erythrocytes. Science (New York, N.Y.) 243 20466936
2007 Heparan sulfate proteoglycans provide a signal to Plasmodium sporozoites to stop migrating and productively invade host cells. Cell host & microbe 208 18005753
2006 A calcium-dependent protein kinase regulates Plasmodium ookinete access to the midgut epithelial cell. Molecular microbiology 188 16430692
2008 Gene expression signatures and small-molecule compounds link a protein kinase to Plasmodium falciparum motility. Nature chemical biology 180 18454143
2009 A cyclic GMP signalling module that regulates gliding motility in a malaria parasite. PLoS pathogens 158 19779564
2008 The motor complex of Plasmodium falciparum: phosphorylation by a calcium-dependent protein kinase. The Journal of biological chemistry 147 18768477
2012 A Plasmodium calcium-dependent protein kinase controls zygote development and transmission by translationally activating repressed mRNAs. Cell host & microbe 143 22817984
2015 Phosphoproteomics reveals malaria parasite Protein Kinase G as a signalling hub regulating egress and invasion. Nature communications 136 26149123
2006 Plasmodium berghei calcium-dependent protein kinase 3 is required for ookinete gliding motility and mosquito midgut invasion. Molecular microbiology 127 16796674
2014 Pyrazoleamide compounds are potent antimalarials that target Na+ homeostasis in intraerythrocytic Plasmodium falciparum. Nature communications 104 25422853
2004 Export of Plasmodium falciparum calcium-dependent protein kinase 1 to the parasitophorous vacuole is dependent on three N-terminal membrane anchor motifs. Molecular microbiology 92 15491359
2012 Transmission of malaria to mosquitoes blocked by bumped kinase inhibitors. The Journal of clinical investigation 88 22565309
2017 PfCDPK1 mediated signaling in erythrocytic stages of Plasmodium falciparum. Nature communications 80 28680058
1993 Gene structure and expression of an unusual protein kinase from Plasmodium falciparum homologous at its carboxyl terminus with the EF hand calcium-binding proteins. The Journal of biological chemistry 80 8440720
2012 Characterization of Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK1) and its role in microneme secretion during erythrocyte invasion. The Journal of biological chemistry 79 23204525
2013 A specific inhibitor of PfCDPK4 blocks malaria transmission: chemical-genetic validation. The Journal of infectious diseases 78 24123773
2011 Structural and evolutionary divergence of eukaryotic protein kinases in Apicomplexa. BMC evolutionary biology 70 22047078
1994 Calcium-binding properties of a calcium-dependent protein kinase from Plasmodium falciparum and the significance of individual calcium-binding sites for kinase activation. Biochemistry 68 8142371
2012 Subcellular location, phosphorylation and assembly into the motor complex of GAP45 during Plasmodium falciparum schizont development. PloS one 55 22479457
2004 Evidence for differing roles for each lobe of the calmodulin-like domain in a calcium-dependent protein kinase. The Journal of biological chemistry 53 15126505
2022 Expansion microscopy of Plasmodium gametocytes reveals the molecular architecture of a bipartite microtubule organisation centre coordinating mitosis with axoneme assembly. PLoS pathogens 52 35077503
2005 Structure of the regulatory apparatus of a calcium-dependent protein kinase (CDPK): a novel mode of calmodulin-target recognition. Journal of molecular biology 48 16430916
1994 Plasmodium falciparum calcium-dependent protein kinase phosphorylates proteins of the host erythrocytic membrane. Molecular and biochemical parasitology 42 7808482
1997 Molecular cloning and characterization of a second calcium-dependent protein kinase of Plasmodium falciparum. Molecular and biochemical parasitology 40 9247932
2013 Substituted imidazopyridazines are potent and selective inhibitors of Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK1). Bioorganic & medicinal chemistry letters 39 23570789
2021 Plasmodium falciparum Calcium-Dependent Protein Kinase 4 is Critical for Male Gametogenesis and Transmission to the Mosquito Vector. mBio 38 34724830
2016 Reduced Activity of Mutant Calcium-Dependent Protein Kinase 1 Is Compensated in Plasmodium falciparum through the Action of Protein Kinase G. mBio 36 27923926
2014 Optimization of an imidazopyridazine series of inhibitors of Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK1). Journal of medicinal chemistry 36 24689770
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2020 Overlapping and distinct roles of CDPK family members in the pre-erythrocytic stages of the rodent malaria parasite, Plasmodium berghei. PLoS pathogens 22 32866196
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