Microbiology

Parasite Palmitoylation

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Science  04 Oct 2013:
Vol. 342, Issue 6154, pp. 17
DOI: 10.1126/science.342.6154.17-c

The molecular mechanisms involved in the active invasion processes used by apicomplexan parasites such as Toxoplasma gondii to enter host cells are not well understood. Compounds that inhibit—or in some cases enhance—the infectivity of T. gondii parasites were recently identified in a chemical-genetic screen. How such small-molecule invasion enhancers might work, however, remains obscure. Child et al. have now been able to identify the molecular target of one class of small-molecule enhancers: a Toxoplasma enzyme, palmitoyl protein thioesterase-1 (TgPPT1). Inhibiting this thioesterase enhanced the invasive capacity of tachyzoites by increasing parasite motility and promoting secretion from micronemes, the parasite's invasion-associated organelles. TgPPT1 acts as a depalmitoylase, removing fatty acids that have been attached to proteins post-translationally. Thus, reversible palmitoylation within the parasite appears to play a key role in the invasion of host cells by T. gondii.

Nat. Chem. Biol. 9, 651 (2013).

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