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Updated: May 30, 2025

Toxoplasma gondii Cyst Wall Formation in Activated Bone Marrow-derived Macrophages and Bradyzoite Conditions
Published on: August 12, 2010
Toxoplasma chitinase-like protein orchestrates cyst wall glycosylation to facilitate effector export and cyst
Yong Fu1, Tadakimi Tomita2, Louis M Weiss2,3
1Department of Molecular Microbiology, Washington University in St. Louis, School of Medicine, St. Louis, MO 63130.
Abstract:
Toxoplasma bradyzoites reside in tissue cysts that undergo cycles of expansion, rupture, and release to foster chronic infection. The glycosylated cyst wall acts as a protective barrier, although the processes responsible for formation, remodeling, and turnover are not understood. Herein, we identify a noncanonical chitinase-like enzyme TgCLP1 that localizes to micronemes and is targeted to the cyst wall after secretion. Genetic deletion of TgCLP1 resulted in a thickened cyst wall that decreased cyst turnover, blocked the export of virulence effectors into host cells, and resulted in failure to persist during chronic infection. Genetic complementation with a series of mutants revealed that the GH19 glycosidase domain was crucial for regulating glycosylation of several glycoproteins in the cyst wall. Overall, our findings reveal that TgCLP1 is a multifunctional survival factor that modifies glycoproteins within the cyst wall to modulate export of virulence effectors and regulate turnover of tissue cysts.
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