Ao Yangsiqi, Yang Fuxian, Li Jieping, Gong Xiaoqing, Liu Huimin, Wu Yilin, Zhu Ping, Xu Yanhua, Li Na, Xu Rui, Guo Yaqiong, Sibley L David, Xiao Lihua, Feng Yaoyu
State Key Laboratory for Animal Disease Control and Prevention, Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA.
Microbiol Res. 2025 Nov;300:128284. doi: 10.1016/j.micres.2025.128284. Epub 2025 Jul 19.
The parasite Cryptosporidium modulates the host cell cytoskeleton and microvilli during invasion and development. Identification of effector molecules and their targets is essential for understanding parasite-host interactions and pathogenesis. Here, we examined seven mucin glycoproteins (MUC1-MUC7) located on chromosome 2 of Cryptosporidium parvum using gene tagging. These small proteins are expressed in different secretory organelles including dense granules (DG), small granules (SG), and the rhoptry (ROP), and all but one are exported to the cytoplasm or microvilli of infected cells. Mutational studies of MUC5 revealed that its N-terminus contains a host cell targeting motif with a critical leucine residue at position 39. Immunoprecipitation and mutational studies showed that MUC5 interacts with the host cytoskeleton via its Px(P/A)xPR motifs and the SH3 domain of CD2AP. Deletion of MUC5 reduced the pathogenicity of a virulent isolate. These findings demonstrate the export of multiple Cryptosporidium DG and SG proteins into host cells and microvilli, and reveal a novel molecular mechanism by which Cryptosporidium effectors modulate the host cytoskeleton.
寄生虫隐孢子虫在入侵和发育过程中会调节宿主细胞的细胞骨架和微绒毛。鉴定效应分子及其靶点对于理解寄生虫与宿主的相互作用及发病机制至关重要。在此，我们使用基因标签研究了位于微小隐孢子虫2号染色体上的七种黏蛋白糖蛋白（MUC1 - MUC7）。这些小蛋白在不同的分泌细胞器中表达，包括致密颗粒（DG）、小颗粒（SG）和棒状体（ROP），除一种外，其余均被转运至受感染细胞的细胞质或微绒毛中。对MUC5的突变研究表明，其N端含有一个宿主细胞靶向基序，在第39位有一个关键的亮氨酸残基。免疫沉淀和突变研究表明，MUC5通过其Px(P/A)xPR基序和CD2AP的SH3结构域与宿主细胞骨架相互作用。缺失MUC5会降低强毒株的致病性。这些发现证明了多种隐孢子虫DG和SG蛋白可转运至宿主细胞和微绒毛中，并揭示了隐孢子虫效应分子调节宿主细胞骨架的一种新分子机制。
