Cryptosporidium uses multiple distinct secretory organelles to interact with and modify its host cell

Cryptosporidium is a leading cause of diarrheal disease in children and an important contributor to early childhood mortality. The parasite invades and extensively remodels intestinal epithelial cells, building an elaborate interface structure. How this occurs at the molecular level and the contributing parasite factors are largely unknown. Here, we generated a whole-cell spatial proteome of the Cryptosporidium sporozoite and used genetic and cell biological experimentation to discover the Cryptosporidium-secreted effector proteome. These findings reveal multiple organelles, including an original secretory organelle, and generate numerous compartment markers by tagging native gene loci. We show that secreted proteins are delivered to the parasite-host interface, where they assemble into different structures including a ring that anchors the parasite into its unique epicellular niche. Cryptosporidium thus uses a complex set of secretion systems during and following invasion that act in concert to subjugate its host cell. [Display omitted] •1,107 Cryptosporidium proteins were assigned to their cellular locations through the use of hyperLOPIT•Four distinct secretory organelles were shown to be discharged during host interaction•More than 150 putative Cryptosporidium effectors were identified Cryptosporidium is a leading cause of diarrheal disease, yet how the parasite modifies host enterocytes is unknown. Guérin et al. established and validated the spatial proteome of Cryptosporidium sporozoites and identified the content of multiple secretory organelles, providing a comprehensive set of putative virulence factors to understand host-parasite interaction.