Biology subjects

Wilcke, L.

Publications and source records attributed to Wilcke, L..

3 recordsLinked to original sources

bioRxiv2021

Global analysis of putative phospholipases in the malaria parasite Plasmodium falciparum reveals critical factors for parasite proliferation

For its replication within red blood cells, the malaria parasite is highly dependent on correctly regulated lipid metabolism. Enzymes involved in lipid metabolic processes are therefore potential drug targets. We here provide a functional analysis of the 20 putative phospholipases that are expressed by asexual blood stages of Plasmodium falciparum. We reveal a high level of redundancy among members of this group, but using conditional mislocalization and gene disruption techniques we show that the phosphoinositide-specific phospholipase C (PF3D7_1013500) has a previously unrecognized essential role in intracellular parasite maturation. In addition, we demonstrate that the patatin-like phospholipase PF3D7_1358000 localizes to the mitochondrion. Parasites lacking this enzyme display a severe growth phenotype and defects in mitochondrial morphogenesis and function leading to hypersensitivity towards proguanil and inhibitors of the mitochondrial electron transport chain including atovaquone. This demonstrates that regulated mitochondrial lipid homeostasis is necessary for mitochondrial function and coordinated division during parasite multiplication.

microbiology↗

bioRxiv2021

Identification of novel inner membrane complex and apical annuli proteins of the malaria parasite Plasmodium falciparum

The inner membrane complex (IMC) is a defining feature of apicomplexan parasites, which confers stability and shape to the cell, functions as a scaffolding compartment during the formation of daughter cells and plays an important role in motility and invasion during different life cycle stages of these single celled organisms. To explore the IMC proteome of the malaria parasite Plasmodium falciparum we applied a proximity-dependent biotin identification (BioID)-based proteomics approach, using the established IMC marker protein Photosensitized INA-Labelled protein 1 (PhIL1) as bait in asexual blood-stage parasites. Subsequent mass spectrometry-based peptide identification revealed enrichment of twelve known IMC proteins and several uncharacterized candidate proteins. We validated nine of these previously uncharacterized proteins by endogenous GFP-tagging. Six of these represent new IMC proteins, while three proteins have a distinct apical localization that most likely represent structures described as apical annuli in Toxoplasma gondii. Additionally, various Kelch13 interacting candidates were identified, suggesting an association of the Kelch13 compartment and the IMC in schizont and merozoite stages. This work extends the number of validated IMC proteins in the malaria parasite and reveals for the first time the existence of apical annuli proteins in P. falciparum. Additionally, it provides evidence for a spatial association between the Kelch13 compartment and the IMC in late blood-stage parasites.

cell biology↗

bioRxiv2020

Structure-based identification and functional characterization of an essential lipocalin in the malaria parasite Plasmodium falciparum

Proteins of the lipocalin family are known to bind small hydrophobic ligands and are involved in various physiological processes ranging from lipid transport to oxidative stress responses. The genome of the malaria parasite Plasmodium falciparum contains a single protein PF3D7_0925900 with a lipocalin signature. Using crystallography and small-angle X-ray scattering, we show that the protein has a tetrameric structure of typical lipocalin monomers, hence we name it P. falciparum lipocalin (PfLCN), the first lipocalin structurally and functionally characterized in a single-celled eukaryote. We show that PfLCN is expressed in the intraerythrocytic stages of the parasite and localizes to the parasitophorous and food vacuoles. Conditional knockdown of PfLCN impairs parasite development, which can be rescued by treatment with the radical scavenger Trolox or by temporal inhibition of hemoglobin digestion. This suggests a key function of PfLCN in counteracting oxidative stress induced cell damage during multiplication of parasites within red blood cells.

cell biology↗