Phenotypic Screens Identify Parasite Genetic Factors Associated with Malarial Fever Response in Plasmodium falciparum
            <i>piggyBac</i>
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Thomas, Phaedra; Sedillo, Jennifer L.; Oberstaller, Jenna; Li, Suzanne; Zhang, Min; Singh, Naresh; Wang, Chengqi C. Q.; Udenze, Kenneth O.; Jiang, Rays H. Y.; Adams, John

doi:10.1128/msphere.00273-16

Cited by 20 publications

(22 citation statements)

References 20 publications

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“…Although no consistent growth defect was observed upon deletion of any exported FIKK kinase after 120 hours under optimal cell culture conditions, a recent genetic screen indicated that disruption of some FIKKs may have a fitness defect over a longer time scale 69 , and some FIKKs were refractory to non-conditional gene deletion 70 . Additionally, FIKK9.3 has been implicated in providing some protection against elevated temperatures, suggesting it may be important during fever 71 .…”

Section: Discussionmentioning

confidence: 99%

An exported kinase family mediates species-specific erythrocyte remodelling and virulence in human malaria

et al. 2020

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Summary The most severe form of human malaria is caused by Plasmodium falciparum . Its virulence is closely linked to the increase in rigidity of infected erythrocytes and their adhesion to endothelial receptors, obstructing blood flow to vital organs. Unlike other human-infecting Plasmodium species, P. falciparum exports a family of 18 ‘FIKK’ serine/threonine kinases into the host cell, suggesting that phosphorylation may modulate erythrocyte modifications. We reveal substantial species-specific phosphorylation of erythrocyte proteins by P. falciparum , but not by Plasmodium knowlesi , which does not export FIKK kinases. By conditionally deleting all FIKK kinases combined with large-scale quantitative phosphoproteomics we identify unique phosphorylation fingerprints for each kinase, including phosphosites on parasite virulence factors and host erythrocyte proteins. Despite their non-overlapping target sites, a network analysis reveals that some FIKKs may act in the same pathways. Only deletion of the non-exported kinase FIKK8 resulted in reduced parasite growth, suggesting the exported FIKKs may instead support functions important for survival within the host. We show that one kinase, FIKK4.1, mediates both rigidification of the erythrocyte cytoskeleton and trafficking of the adhesin and key virulence factor PfEMP1 to the host cell surface. This establishes the FIKK family as important drivers of parasite evolution and malaria pathology.

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Section: Discussionmentioning

confidence: 99%

An exported kinase family mediates species-specific erythrocyte remodelling and virulence in human malaria

et al. 2020

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“…Increasing PI(3)P levels by ectopically expressing a human PI3K, Vps34, in P. falciparum confers similar resistance ( Mbengue et al, 2015 ). Intriguingly, a phenotypic screen using piggyBac mutagenesis showed a reduced heat tolerance in a pfkelch13 -upregulated P. falciparum mutant ( Thomas et al, 2016 ). If Pfkelch13 expression is inversely correlated with PI(3)P levels, the phenotype observed with the pfkelch13 -upregulated strain presents an intriguing possibility that PI(3)P may be connected to parasite fitness under heat stress ( Mbengue et al, 2015 ).…”

Section: Introductionmentioning

confidence: 99%

Phosphatidylinositol 3-phosphate and Hsp70 protect Plasmodium falciparum from heat-induced cell death

Pasaje

Srivastava

et al. 2020

eLife

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Phosphatidylinositol 3-phosphate (PI(3)P) levels in Plasmodium falciparum correlate with tolerance to cellular stresses caused by artemisinin and environmental factors. However, PI(3)P function during the Plasmodium stress response was unknown. Here, we used PI3K inhibitors and antimalarial agents to examine the importance of PI(3)P under thermal conditions recapitulating malarial fever. Live cell microscopy using chemical and genetic reporters revealed that PI(3)P stabilizes the digestive vacuole (DV) under heat stress. We demonstrate that heat-induced DV destabilization in PI(3)P-deficient P. falciparum precedes cell death and is reversible after withdrawal of the stress condition and the PI3K inhibitor. A chemoproteomic approach identified PfHsp70-1 as a PI(3)P-binding protein. An Hsp70 inhibitor and knockdown of PfHsp70-1 phenocopy PI(3)P-deficient parasites under heat shock. Furthermore, PfHsp70-1 downregulation hypersensitizes parasites to heat shock and PI3K inhibitors. Our findings underscore a mechanistic link between PI(3)P and PfHsp70-1 and present a novel PI(3)P function in DV stabilization during heat stress.

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“…This mutant carries a single transposon insertion in the 5’ UTR of k13 in the NF54 background. Studies utilizing QISeq verified the absence of other changes in the genomic background [ 23 , 24 ]. Given K13’s BTB and propeller domains structural similarity to the transcriptional regulator Keap1, we hypothesized that dysregulation of K13 will result in an altered transcriptome of functionally-connected genes.…”

Section: Introductionmentioning

confidence: 99%

Altered expression of K13 disrupts DNA replication and repair in Plasmodium falciparum

et al. 2018

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BackgroundPlasmodium falciparum exhibits resistance to the artemisinin component of the frontline antimalarial treatment Artemisinin-based Combination Therapy in South East Asia. Millions of lives will be at risk if artemisinin resistance (ART-R) spreads to Africa. Single non-synonymous mutations in the propeller region of PF3D7_1343700,“K13” are implicated in resistance. In this work, we use transcriptional profiling to characterize a laboratory-generated k13 insertional mutant previously demonstrated to have increased sensitivity to artemisinins to explore the functional role of k13.ResultsA set of RNA-seq and microarray experiments confirmed that the expression profile of k13 is specifically altered during the early ring and early trophozoite stages of the mutant intraerythrocytic development cycle. The down-regulation of k13 transcripts in this mutant during the early ring stage is associated with a transcriptome advance towards a more trophozoite-like state. To discover the specific downstream effect of k13 dysregulation, we developed a new computational method to search for differential gene expression while accounting for the temporal sequence of transcription. We found that the strongest biological signature of the transcriptome shift is an up-regulation of DNA replication and repair genes during the early ring developmental stage and a down-regulation of DNA replication and repair genes during the early trophozoite stage; by contrast, the expressions of housekeeping genes are unchanged. This effect, due to k13 dysregulation, is antagonistic, such that k13 levels are negatively correlated with DNA replication and repair gene expression.ConclusionOur results support a role for k13 as a stress response regulator consistent with the hypothesis that artemisinins mode of action is oxidative stress and k13 as a functional homolog of Keap1 which in humans regulates DNA replication and repair genes in response to oxidative stress.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-5207-7) contains supplementary material, which is available to authorized users.

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Phenotypic Screens Identify Parasite Genetic Factors Associated with Malarial Fever Response in Plasmodium falciparum piggyBac Mutants

Cited by 20 publications

References 20 publications

An exported kinase family mediates species-specific erythrocyte remodelling and virulence in human malaria

An exported kinase family mediates species-specific erythrocyte remodelling and virulence in human malaria

Phosphatidylinositol 3-phosphate and Hsp70 protect Plasmodium falciparum from heat-induced cell death

Altered expression of K13 disrupts DNA replication and repair in Plasmodium falciparum

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