This year the annual EMBL Conference ‘BioMalPar XIX: biology and pathology of the malaria parasite’ took place 23 – 25 May in a hybrid format. If you have been to BioMalPar before, you know how special this community is and that you wouldn’t want to miss the event!

One essential and always exciting part of the event is the poster sessions, as you get to discover what labs around the world are up to. Here we present you with the two best poster prize winners and acknowledge the honourable mentions. Also, if you would like to immerse yourself in more detail into what happened at the conference, you can read this detailed report written by MESA Correspondents Faith Hungwe (KTH Royal Institute of Technology, Karolinska Institute and Stockholm University, Sweden), Aaron Lartey (Noguchi Memorial Institute for Medical Research, Ghana) and Rinter Karimi (University of Glasgow, UK) who did a great job covering the sessions at the conference.

The phosphatase UIS2 is needed for protein export in malaria parasites

Presenter: Carolina Castro Peña

Abstract: Malaria blood stage parasites reside in a compartment termed the parasitophorous vacuole (PV) that is formed by the PV membrane (PVM). This compartment has critical roles in nutrient acquisition and the export of parasite proteins into the host cell. We previously identified the serine/threonine protein phosphatase UIS2 as the most prominent hit in a BioID of the PV compartment (Kosh-Naucke et al. 2018, PMID:*28784333). To understand the function of this protein we generated a diCre based conditional knock out. The uis2-KO parasites showed a severe growth defect indicating an important function of UIS2 for blood stage development. Phenotypic analyses revealed an export defect for all tested classes of exported proteins in the uis2-KO, while transport to the parasite plasma membrane or the PV was still intact, indicating a defect specific for protein export. Complementation of the uis2-KO with wild type reverted the phenotype while complementation with uis2 versions with mutations affecting critical phosphatase catalytic site residues did not, indicating that the phosphatase activity of UIS2 is needed for its function. In previous work, we found that UIS2 most likely is bound to the inner face of the PVM. However, we did not find evidence for proximity of UIS2 to the PTEX translocon components, as these were not significantly enriched in UIS2 DiQ-BioID experiments. Interestingly, UIS2 shares homology with the Toxoplasma gondii PV phosphatase GRA44, which is needed for effector export and associated with the translocon complex MYR, which is presumed absent in Plasmodium parasites. Hence, our work indicates that UIS2 has a similar function in both genera despite the absence of the MYR components in malaria parasites.

Due to the confidentiality of the unpublished data, we cannot share the poster.

Is mitochondrial respiration essential for male gametogenesis in P falciparum?

Presenter: Penny Sparkes

Abstract: Gametocytes are essential for human-to-mosquito transmission of Plasmodium. However, many aspects of their cell biology remain poorly understood, one of which is energy metabolism. Whereas asexual blood stage parasites rely on glycolysis for energy generation, gametocytes upregulate their tricarboxylic acid (TCA) cycle. This coincides with the enlargement of the gametocyte mitochondria into a complex, cristate structure. Both male and female gametocytes enlarge their mitochondrion in this way, but only the female gametocyte passes its mitochondrion onto the new zygote with males shedding theirs to become gametes. Mitochondrial respiration can result in the production of harmful reactive oxygen species which may affect the longevity of circulating gametocytes. Therefore, why does the male gametocyte invest in growing a large complex organelle only to discard it at the next developmental stage, particularly one that may damage the gametocyte during its long development in the human host?
Little is known about whether male and female gametocyte mitochondria differ in their structure and function. One barrier to studying sex differences in gametocytes is the lack of validated sex-specific tools. To meet this need, we raised an antibody to PF3D7_1325200 – a gene predicted to have specific expression in male gametocytes. By immunofluorescence, we confirm this gene is specific for male gametocytes. We used this new tool and functional mitochondrial labelling to address the following questions, i) does mitochondrial morphology and activity differ between males and females, ii) do male and female gametocytes show different responses to mitochondria-targeting drugs, iii) is mitochondrially produced ATP essential for male gametogenesis?

Due to the confidentiality of the unpublished data, we cannot share the poster.

Honourable mentions

Gala Ramon Zamorano, Bernhard Nocht Institute for Tropical Medicine, Germany

‘The protein landscape of the chromatin states in P. falciparum parasites’

James Thomas, London School of Hygiene and Tropical Medicine, United Kingdom

‘Unravelling the role of the apical membrane antigen-1 cytoplasmic domain during Plasmodium merozoite invasion of erythrocytes’

Prince Ubiaru, University of Glasgow, United Kingdom

‘Genetics of the interaction between Plasmodium falciparum and Anopheles  albimanus’

Shany Assaraf, The Hebrew University of Jerusalem, Israel

‘The uORF regulating pregnancy malaria encodes for a novel protein involved in ER Stress Response’

Yannick Daniel Höppner, Bernhard Nocht Institute for Tropical Medicine, Germany

‘Impact of longitudinally acquired host immunity on P. falciparum var gene expression’

David Anaguano-Pillajo, University of Georgia, USA

‘Plasmodium falciparum requires two rhoptries to invade host red blood cells’