Poster Presentation Lorne Infection and Immunity 2013

Characterising a hypothetical component of the Plasmodium translocon of exported proteins (PTEX) in malaria parasites (#109)

Scott Chisholm 1 , Ming Kalanon 1 , Kathryn Matthews 1 , Catherine Nie 2 , Brendan Crabb 2 , Paul Gilson 2 , Tania de Koning-Ward 1
  1. Deakin University, Waurn Ponds, VIC, Australia
  2. Burnet Institute, Prahran, VIC, Australia

Plasmodium parasites extensively remodel their host erythrocytes by exporting hundreds of their proteins across their parasitophorous vacuole membrane (PVM) into the host cell. This process allows the parasite to acquire its nutrients and prevent clearance from its human host. The mechanism by which parasites export these proteins across the PVM has not been determined; however it is believed that the Plasmodium translocon of exported proteins (PTEX) may act in facilitating this process. One identified putative component of this translocon, PTEX88, has no conserved domains predictive of function, and with no reagents available, little is known about this protein. Knockout studies have shown that PTEX88 is essential for parasite survival. In order to gain insight into how PTEX88 may function within translocation machinery, we have generated reagents to PTEX88 in P. falciparum, including peptide antibodies and a parasite line expressing PTEX88 with an epitope tag. We have used these reagents to gain a basic understanding of PTEX88, such as the expression profile, localisation and its interacting partners. Furthermore, PTEX is conserved in the rodent malaria species P. berghei, and similar reagents to the P. berghei PTEX88 homologue have been generated in order to determine whether PTEX88 functions in a similar way in this species, which exports a much smaller number of proteins. Our data shows interaction of PTEX88 with known PTEX components, by immunofluorescence and immunoprecipitation experiments. We have also shown that PTEX88 has also shown similar expression profiles to other PTEX components, further strengthening the case that PTEX88 may be functioning within this complex. Further analysis is required to confirm the interaction of PTEX88 within this complex, and what role it may be playing in the process of protein export.