Cell Biology

Stripped and Eliminated

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Science  22 Sep 2006:
Vol. 313, Issue 5794, pp. 1705
DOI: 10.1126/science.313.5794.1705a

Protozoan parasites such as Plasmodium and Toxoplasma invade host cells and divide within a parasitophorous vacuole. The vacuolar membrane is modified by the invading parasite in order to forestall its fusion with host endocytic and degradative organelles (lysosomes). Ling et al. have examined how mouse macrophages, after being infected by T. gondii, can break through this parasite-constructed defensive wall. Cells from mice lacking an interferon-γ-inducible p47 GTPase (IGTP) failed to eliminate the pathogen. In contrast, in wild-type cells the parasitophorous vacuole membrane was disrupted during the degradation process, and the parasite plasma membrane was stripped away. The parasite was then engulfed by a double-membrane autophagosome, which fused with lysosomes, leading to destruction of the parasite. Recently, IGTPs have been shown to play a similar role in the elimination of intracellular Mycobacterium in mice and in humans (Singh et al., Reports, 8 September 2006, p. 1438). — SMH

J. Exp Med. 203, 2063 (2006).

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