Apicomplexan Pore-Forming Toxins

Pore-forming toxins (PFTs) are released by one cell to directly inflict damage on another cell. Hosts use PFTs, including members of the membrane attack complex/perforin protein family, to fight infections and cancer, while bacteria and parasites deploy PFTs to promote infection. Apicomplexan parasites secrete perforin-like proteins as PFTs to egress from infected cells and traverse tissue barriers. Other protozoa, along with helminth parasites, utilize saposin-like PFTs prospectively for nutrient acquisition during infection. This review discusses seminal and more recent advances in understanding how parasite PFTs promote infection and describes how they are regulated and fulfill their roles without causing parasite self-harm. Although exciting progress has been made in defining mechanisms of pore formation by PFTs, many open questions remain to be addressed to gain additional key insights into these remarkable determinants of parasitic infections.