Peculiarities of host cholesterol transport to the unique intracellular vacuole containing
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Sehgal, A and Bettiol, SS and Pypaert, M and Wenk, MR and Kaasch, A and Blader, IJ and Joiner, KA and Coppens, I, Peculiarities of host cholesterol transport to the unique intracellular vacuole containing
Toxoplasma, Traffic, 6, (12) pp. 1125-1141. ISSN 1398-9219 (2005) [Refereed Article]
The intracellular protozoan Toxoplasma gondii is auxo-trophic for low-density lipoprotein (LDL)-derived cholesterol (C). We previously showed that T. gondii scavenges this essential lipid from host endolysosomal compartments and that C delivery to the parasitophorous vacuole (PV) does not require transit through host Golgi or encdoplasmic reticulum. In this study, we explore the itinerary of C from the host endolysosomes; to the PV. Labeled C incorporated into LDL is rapidly detected in intravacuolar parasites and partially esterified by the parasites. In contrast to diverse mammalian organelles, the post-endolysosomal transfer of to the PV does not involve the host plasma membrane as an intermediate. Nevertheless, the PV membrane is accessible to extracellular sterol acceptors, suggesting C trafficking from intracellular parasites to host plasma membrane. C movement to the PV requires temperatures permissive for vesicular transport, metabolic energy and functional microtubules Host caveolae vesicles and the sterol carrier protein-2 do not participate in this process. Proteolytic treatment of purified PV or free parasites abolishes C acquisition by the parasites. Altogether, these results support a vesicular transport system from host endolysosomes to the PV, and a requirement for PV membrane and parasite plasma membrane proteins in C delivery to T. gondii. Copyright © Blackwell Munksgaard 2005.
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