Proteintranslokation über die Membran der parasitophoren Vakuole im Plasmodium falciparum-infizierten Erythrozyten

The parasite Plasmodium falciparum modifies its host cell during the erythrocytic development via export of proteins, which secure its survival within the erythrocyte. During this process, proteins have to cross a cellular compartment called parasitophorous vacuole, whose membrane isolates the parasite from its host cell. Since the transport of proteins across the parasitophorous vacuolar membrane is an object of intense research, only limited information is provided concerning the mechnism. Despite the signal mediation via HT/PEXEL nothing is known about how proteins traverse the membrane. Since a few years ago the assumption exists that this process involves a translocator-mediated process, which was analysed in detail within this work. In doing so an in vitro assay, based on Ansorge et al. (1996), was optimised to investigate the translocation of the glycophorine-binding protein across the PVM. Using this assay, it was shown that trypsin-sensitive proteins, which were accessible for the protease on the cytosolic side of the PVM, and soluble protein components of the host mediate the translocation across the PVM. Furthermore it was shown that hydrolysis of ATP as an energy equivalent for the translocation process is needed. Even though the involved protein components were not clearly identified, the results indicate a general mechanism in apicomlexan parasites which allows parasitism of different host cells. The aspects of parasite protein export into the host cell investigated within this work support the assumption of the existence of a protein translocator within the PVM and also provide an assay useful for reliable investigation of aspects of the translocation mechanism in future studies.