| 2004 |
CDPK4 is essential for cell cycle progression in male gametocytes of P. berghei; genetic disruption of CDPK4 blocks sexual reproduction and mosquito transmission. Xanthurenic acid (XA) triggers a rapid cytosolic calcium rise in gametocytes, and CDPK4 acts as the molecular switch translating this calcium signal into cellular response regulating male gametocyte cell cycle progression. |
Gene disruption in P. berghei; bioluminescent calcium sensor imaging; gametocyte activation assays |
Cell |
High |
15137943
|
| 2009 |
PfCDPK4 kinase activity requires its catalytic lysine residue (mutation to alanine abolishes phosphorylation). PfCDPK4 phosphorylation is activated by increased Ca2+ concentration, decreased temperature, and elevated pH (mimicking mosquito bloodmeal conditions). Its activity in the parasite is regulated by phospholipase C. PfCDPK4 is localized to the gametocyte periphery. The Junction Domain (JD) plays a pivotal role in PfCDPK4 regulation, with mapped regions interacting with both the kinase domain and the calmodulin-like domain. |
Active-site mutagenesis (K→A); in vitro phosphorylation assay with [γ-32P]ATP; phosphatase treatment; immunofluorescence localization; phospholipase C inhibition assay |
The Journal of biological chemistry |
High |
19307175
|
| 2009 |
PfCDPK4 is a calcium-activated kinase; its phosphorylation activity is eliminated by mutation of its putative catalytic lysine. PfCDPK4 is overexpressed in day 15 gametocytes exposed to xanthurenic acid or human serum and shows activation under conditions mimicking the mosquito bloodmeal (lower temperature, higher pH, elevated Ca2+). |
Recombinant protein purification; [γ-32P]ATP labeling; phosphatase treatment; active-site mutagenesis; western blot expression analysis |
Parasitology international |
Medium |
19666141
|
| 2011 |
Trifluoperazine non-competitively inhibits PfCDPK4 in the micromolar range by targeting its calmodulin-like domain, demonstrating that selective inhibition of PfCDPK4 can be achieved through this domain. |
In vitro enzyme inhibition assay with trifluoperazine and other calmodulin antagonists; kinetic analysis of inhibition mechanism |
Protein and peptide letters |
Medium |
21787279
|
| 2012 |
Bumped kinase inhibitors (BKIs) block microgametocyte exflagellation and oocyst/sporozoite formation by inhibiting CDPK4; the small serine gatekeeper residue in the CDPK4 active site confers selectivity over mammalian kinases. |
In vitro exflagellation assay; mosquito feeding experiments; mammalian cell proliferation assay; in vivo mouse pharmacokinetics |
The Journal of clinical investigation |
Medium |
22565309
|
| 2013 |
Chemical-genetic validation confirms that CDPK4 is the direct target of bumped kinase inhibitor compound 1294: P. falciparum parasites expressing a drug-resistant methionine gatekeeper mutant (S147M) at the CDPK4 active site show a shift in exflagellation EC50, and the small serine gatekeeper residue (S147) is responsible for BKI selectivity. |
Chemical-genetic validation: generation of P. falciparum S147M CDPK4 gatekeeper mutant parasites; exflagellation EC50 shift assay; pharmacokinetic analysis |
The Journal of infectious diseases |
High |
24123773
|
| 2014 |
Two structural features in the ATP-binding site of PfCDPK4 (including the small serine gatekeeper) can be exploited to obtain potent and selective inhibitors; pyrazolopyrimidine-based inhibitors of PfCDPK4 in vitro activity also block P. falciparum exflagellation without toxicity to human cells. |
In vitro PfCDPK4 kinase inhibition assay; P. falciparum exflagellation assay; cytotoxicity assay |
European journal of medicinal chemistry |
Medium |
24531197
|
| 2016 |
In P. berghei, CDPK4 is required for sporozoite invasion of hepatocytes and sporozoite motility; sporozoites carrying a deletion of CDPK4 are defective in hepatocyte invasion. Unlike PKG inhibition, CDPK4 genetic deletion does not significantly decrease merosome numbers, indicating distinct roles for CDPK4 and PKG in liver stage egress. |
CDPK4 gene deletion in P. berghei; hepatocyte invasion assay; sporozoite motility assay; specific kinase inhibitors; merosome counting |
Molecular microbiology |
High |
27425827
|
| 2017 |
In P. berghei, CDPK4 controls three cell cycle events during microgametogenesis: (1) a myristoylated isoform is activated by Ca2+ within 20 seconds of activation to initiate genome replication, acting via a SAPS-domain family protein involved in S-phase entry; (2) CDPK4 is required for mitotic spindle assembly, phosphorylating a microtubule-associated protein important for spindle formation; (3) a non-myristoylated isoform is essential for cytokinesis by activating flagellum motility, linked to phosphorylation of a flagellar protein. |
Analysis of isoform-specific mutants (myristoylation-site mutants); live imaging; phosphoproteomic analysis; identification of SAPS-domain protein as substrate; identification of microtubule-associated protein substrate; in vitro kinase assays |
eLife |
High |
28481199
|
| 2017 |
Phosphoproteomic analysis of P. berghei CDPK4 mutant gametocytes during the first minute of gametogenesis reveals distinct phosphoproteomic disruptions compared to SRPK1 mutants, consistent with CDPK4 controlling broad cell cycle phosphorylation events during male gametogenesis. CDPK4 mutants show disruptions in phosphorylation of proteins related to distinct cell cycle events. |
High-resolution time course phosphoproteomics of CDPK4 mutant vs. wild-type gametocytes; comparison with SRPK1 mutant phosphoproteome |
Cell reports |
Medium |
29141230
|
| 2018 |
In P. berghei, a synthetic negative genetic interaction exists between a hypomorphic allele of PKG and CDPK4 in controlling erythrocyte invasion; CDPK4 becomes critical when PKG-dependent calcium signals are attenuated, phosphorylating proteins important for stability of the inner membrane complex (IMC), which anchors the acto-myosin motor required for motility and invasion. This PKG–CDPK4 epistatic interaction is conserved in P. falciparum. |
Genetic interaction screen (294 kinase interactions in P. berghei); hypomorphic PKG allele combined with CDPK4 deletion; epistasis analysis; phosphoproteomic identification of IMC substrates; conservation validated in P. falciparum |
Nature communications |
High |
30315162
|
| 2020 |
In P. berghei, CDPK4 is required for optimal sporozoite motility and hepatocyte invasion; increased cGMP cannot compensate for loss of CDPK4 during sporozoite invasion (unlike CDPK1 and CDPK5). Chemical inhibition of CDPK4 in liver stages implicates it in merosome formation and/or release. |
Gene deletion of P. berghei CDPK4; sporozoite motility assay; hepatocyte invasion assay; cGMP modulation epistasis; chemical inhibition of CDPK4 in liver stages; merosome counting |
PLoS pathogens |
High |
32866196
|
| 2021 |
P. falciparum CDPK4 gene deletion causes severe defects in male gametogenesis and exflagellation (but not blood-stage growth or gametocyte development). Phosphoproteomic comparison of wild-type and Pfcdpk4 deletion late gametocytes identifies CDPK4-dependent phosphorylation events linked to DNA replication, mRNA translation, and cell motility. In vitro kinase assays identify putative direct substrates; notably, EB1 (End Binding protein 1) is hypophosphorylated in Pfcdpk4 parasites. |
Targeted gene deletion in P. falciparum; exflagellation assay; mass spectrometry-based phosphoproteomics; in vitro kinase substrate assays |
mBio |
High |
34724830
|
| 2022 |
In P. berghei male gametogenesis, CDPK4 is a non-canonical regulator of the bipartite microtubule-organising centre (MTOC) that coordinates mitosis with axoneme assembly; CDPK4 is required for the dynamic architecture of this MTOC. |
Ultrastructure expansion microscopy (U-ExM); Pan-ExM; 3D reconstruction; analysis of CDPK4 mutants |
PLoS pathogens |
Medium |
35077503
|
| 2023 |
PfCDPK4-dependent phosphorylation of EB1 (End Binding protein 1) was identified; EB1 is hypophosphorylated in Pfcdpk4 deletion gametocytes. EB1 loss-of-function (not CDPK4 itself) results in severe nuclear segregation defects in male gametogenesis, placing EB1 as a downstream effector of CDPK4 phosphorylation in male fertility. |
Comparative phosphoproteomics of Pfcdpk4 mutant gametocytes; EB1 gene deletion; male/female sterile genetic crosses; fluorescence microscopy |
mBio |
Medium |
37535401
|
| 2025 |
CDPK4 localizes to the cytoplasmic compartment (distinct from nuclear SRPK1 and MAP2) during P. berghei male gamete formation. Immunoprecipitation reveals CDPK4 interacts with key drivers of rapid DNA replication. Absence of CDPK4 results in severe defects in MTOC organisation and kinetochore segregation during endomitosis. |
Live-cell imaging (localization); immunoprecipitation (interacting partner identification); ultrastructure expansion microscopy; transmission electron microscopy of CDPK4 deletion mutants |
Life science alliance |
Medium |
40127922
|
| 2026 |
In P. berghei, a signaling cascade initiated by CDPK4 upon male gametocyte activation leads to phosphorylation of male-specific early-phosphorylated IDR-rich proteins (MPDs); MPD2 is required for microgamete release and oocyst formation, placing MPD2 as a downstream effector in the CDPK4-initiated phosphorylation cascade during male gametogenesis. |
Phosphoproteomic identification of early-phosphorylated proteins; gene disruption of MPD2 in P. berghei; genetic complementation with tagged MPD2; live-cell imaging; oocyst counting |
Frontiers in cellular and infection microbiology |
Medium |
42620507
|
| 2010 |
PvCDPK4 (Plasmodium vivax ortholog) is expressed at the mature schizont stage and localizes to the schizont by immunofluorescence; recombinant EF-hand domain is produced as a 34 kDa protein, and the protein has four EF-hand motifs for calcium binding. |
Molecular cloning; recombinant protein expression in E. coli; immunofluorescence assay by confocal microscopy |
The Korean journal of parasitology |
Low |
21234235
|