Fu Yong, Tomita Tadakimi, Weiss Louis M, West Christopher M, Sibley L David
Department of Molecular Microbiology, Washington University in St. Louis, School of Medicine, St. Louis, MO 63130.
Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461.
Proc Natl Acad Sci U S A. 2025 Feb 4;122(5):e2416870122. doi: 10.1073/pnas.2416870122. Epub 2025 Jan 29.
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.
缓殖子存在于组织包囊中，这些包囊经历扩张、破裂和释放的循环以促进慢性感染。糖基化的包囊壁起到保护屏障的作用，尽管负责其形成、重塑和更新的过程尚不清楚。在此，我们鉴定出一种非典型的几丁质酶样酶TgCLP1，它定位于微线体，并在分泌后靶向包囊壁。TgCLP1的基因缺失导致包囊壁增厚，包囊更新减少，阻断了毒力效应子向宿主细胞的输出，并导致在慢性感染期间无法持续存在。对一系列突变体的基因互补研究表明，GH19糖苷酶结构域对于调节包囊壁中几种糖蛋白的糖基化至关重要。总体而言，我们的研究结果表明，TgCLP1是一种多功能生存因子，可修饰包囊壁内的糖蛋白，从而调节毒力效应子的输出并调控组织包囊的更新。
