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23 avril 2021: 1 événement

  • Département Biologie des Génomes

    Vendredi 23 avril 16:00-17:00 - Josh Beck - Iowa State University

    Transcending a self-imposed barrier : EXP2/PTEX function in transport across the Malaria parasite vacuole membrane (NOTE : CHANGE OF TIME)

    Résumé : Obligate intracellular malaria parasites undergo development in their hepatocyte and erythrocyte host cells within a vacuolar compartment that is the principal interface between host and parasite. To create a niche for survival in these remarkably diverse cell types, these parasites coordinate a range of transport activities at the vacuole membrane including import of nutrients and export of effector proteins. These processes are best characterized in the blood stage where an arsenal of hundreds of effector proteins are exported into the erythrocyte by the Plasmodium translocon of exported proteins (PTEX) to dramatically remodel this terminally differentiated host cell. PTEX is comprised of the AAA+ unfoldase HSP101 which is coupled to a membrane pore formed by EXP2 via a flange-like adaptor called PTEX150. In addition to its role in protein export, EXP2 also functions in small molecule transport across the vacuole membrane. In contrast to the blood stage, few exported proteins have been identified in the liver stage and the nature of the export machinery is unknown. Curiously, while EXP2 and PTEX150 are both expressed by liver stage parasites, previous studies could not detect HSP101 by fluorescence microscopy. Using a proximity-labeling proteomic strategy, we were similarly unable to detect HSP101 in the liver stage vacuole. These observations indicate major differences in the export machinery and raise the question of EXP2 and PTEX150 function during hepatocyte infection. We are currently using a combination of reverse genetic and proteomic strategies to dissect PTEX roles across blood and liver stages.
    Invited by Joana Santos

    Lieu : visio

    En savoir plus : Département Biologie des Génomes