Nuclear division mechanisms in malaria-causing parasite
Despite being key to rapid proliferation of malaria-causing parasites in the human blood the mechanisms of cell division are still poorly understood. Our vision is to generate a cell biological and genetic framework, which details critical events during this atypical mode of nuclear division. The study of this highly dynamic and small scale process requires exquisite temporal and spatial resolution. Hence, we are using a combination advanced imaging techniques such as live cell, super-resolution and correlative light and electron microscopy to investigate key structural elements of the division machinery. Thereby we hope to uncover new targets within this essential pathway of the parasite’s life cycle.
1 | Organization and composition of the atypical plasmodial centrosomes (Caroline Sophie Simon)
Centrosomes are microtubule organizing centers and master regulators of mitosis. Studying their functionality and composition is critical to understand cell division. The plasmodial centrosomes, however, display a very distinct morphology when compared to any model organism. Based on the poor conservation of canonical centrosome proteins we speculate that divergent factors might govern mitosis in the parasite. We aim to build the first detailed working model for centrosome organization using advanced imaging methods such as STED nanoscopy. To uncover the centrosomal proteome we use in-vivo proximity labeling and mass spectrometry.
Figure 1 | STED nanoscopy of dividing parasite. Image acquired by RescueSTED showing late stage P. falciparum multinucleated parasite, which has infected a human red blood cell. DNA (blue) is stained by Hoechst and microtubules (green) are labeled with anti-Tubulin antibody. Confocal images and zoomed in region are shown on top. Scale bar, 1µm.
2 | Centrin function in malaria parasite division (Yannik Voß)
Centrins are conserved structural proteins involved in centrosome duplication in mammals. P. falciparum possesses four homologues of which two are specific for the phylum of this parasite. In model organisms centrins have been described as calcium-binding contractile elements with the potential to polymerize. We aim to investigate the function of those, likely essential, proteins by inducible knock-out strategies. We complement our in vivo studies with in-vitro biochemical assays using recombinant centrins to test for polymerization, post-translational modification, and interaction partners.
Figure 2 | Structure of PfCentrin1‑4. Schematic indicating the relative size of PfCentrin1‑4, as well as the position of the EF-hand domains (EFh), phosphorylation sites ℗ and acetylation sites (Ac) to scale. N‑terminus (N), C‑terminus © (Cobbold et al., 2016; Ganter et al., 2017; Treeck et al., 2011).
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