Toxoplasma gondii Sequesters Lysosomes from Mammalian Hosts in the Vacuolar Space

Abstract

The intracellular compartment harboring Toxoplasma gondii satisfies the parasite's nutritional needs for rapid growth in mammalian cells. We demonstrate that the parasitophorous vacuole (PV) of T. gondii accumulates material coming from the host mammalian cell via the exploitation of the host endo-lysosomal system. The parasite actively recruits host microtubules, resulting in selective attraction of endo-lysosomes to the PV. Microtubule-based invaginations of the PV membrane serve as conduits for the delivery of host endo-lysosomes within the PV. These tubular conduits are decorated by a parasite coat, including the tubulogenic protein GRA7, which acts like a garrote that sequesters host endocytic organelles in the vacuolar space. These data define an unanticipated process allowing the parasite intimate and concentrated access to a diverse range of low molecular weight components produced by the endo-lysosomal system. More generally, they identify a unique mechanism for unidirectional transport and sequestration of host organelles. © 2006 Elsevier Inc. All rights reserved.