Poster Presentation Lorne Infection and Immunity 2013

Functional analysis and characterisation of the Plasmodium translocon of exported proteins (PTEX) in rodent malaria parasites (#115)

Kathryn Mifsud 1 , Ming Kalanon 1 , Scott Chisholm 1 , Silvia Haase 1 , Angelika Sturm 2 , Dean Goodman 2 , Geoff McFadden 2 , Tania de Koning-Ward 1
  1. Deakin University, Waurn Ponds, VIC, Australia
  2. School of Biosciences, University of Melbourne, Parkville, Victoria, Australia

Central to malaria parasite erythrocytic growth is the translocation of hundreds of its proteins beyond an encasing vacuole into the host cell where they play key roles in virulence and survival.  The Plasmodium Translocon of EXported proteins (PTEX) resides at the parasitophorous vacuole membrane, the interface between the parasite and its host cell, and is predicted to facilitate the passage of parasite exported proteins across the membrane. To investigate the parasites mechanism of protein export and to elucidate the functional role of PTEX in pathogenesis, we are characterising the five components that make up the PTEX complex in the rodent malaria, Plasmodium berghei.   We show that four of the five PTEX components could not be genetically disrupted in P. berghei, in keeping with the pivotal role this machinery is postulated to have in protein export.  In contrast, the component TRX2, a putative thioredoxin like protein, could be targeted by gene disruption and the phenotype of the P. berghei TRX2 knock-out parasite will be presented.  Whilst this indicates that TRX2 is not essential in parasite survival, it suggests that TRX2 plays a regulatory role in PTEX mechanism.  In addition, we have epitope-tagged the PTEX components in P. berghei, which will enable us to characterise these proteins across the malaria life cycle when protein export occurs, including in gametocytes and hepatocytes.