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Toxoplasma evacuoles: a two‐step process of secretion and fusion forms the parasitophorous vacuole
Author(s) -
Håkansson Sebastian,
Charron Audra J.,
Sibley L.David
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.12.3132
Subject(s) - rhoptry , vacuole , biology , microbiology and biotechnology , secretion , endoplasmic reticulum , vesicle , organelle , dense granule , exocytosis , lipid bilayer fusion , endosome , cytosol , cytoplasm , secretory pathway , toxoplasma gondii , apicomplexa , golgi apparatus , biochemistry , immunology , plasmodium falciparum , membrane , malaria , antibody , intracellular , enzyme
Rapid discharge of secretory organelles called rhoptries is tightly coupled with host cell entry by the protozoan parasite Toxoplasma gondii . Rhoptry contents were deposited in clusters of vesicles within the host cell cytosol and within the parasitophorous vacuole. To examine the fate of these rhoptry‐derived secretory vesicles, we utilized cytochalasin D to prevent invasion, leading to accumulation of protein‐rich vesicles in the host cell cytosol. These vesicles lack an internal parasite and are hence termed evacuoles. Like the mature parasite‐containing vacuole, evacuoles became intimately associated with host cell mitochondria and endoplasmic reticulum, while remaining completely resistant to fusion with host cell endosomes and lysosomes. In contrast, evacuoles were recruited to pre‐existing, parasite‐containing vacuoles and were capable of fusing and delivering their contents to these compartments. Our findings indicate that a two‐step process involving direct rhoptry secretion into the host cell cytoplasm followed by incorporation into the vacuole generates the parasitophorous vacuole occupied by Toxoplasma . The characteristic properties of the mature vacuole are likely to be determined by this early delivery of rhoptry components.