Apicomplexan Parasites Co-Opt Host Calpains to Facilitate Their Escape from Infected Cells

Abstract

Let Me Out Apicomplexan parasites like Plasmodium falciparum , which causes malaria, and Toxoplasma gondii , which cause toxoplasmosis, replicate inside animal host cells. In order for infections to spread successfully within the host from cell to cell, daughter parasites after replication need to be able to escape from their incubator cell. In the course of studies intended to elucidate the functions of proteases during parasite infection, Chandramohanadas et al. (p. 794 , published online 2 April) noted that host cell calpain is the only protease present at the right time and place to facilitate the egress of malaria parasites from infected red blood cells. Parasite egress from infected resealed erythrocytes was prevented when calpain was removed. Moreover, T. gondii was unable to escape efficiently from murine fibroblast knockouts lacking a calpain regulatory subunit.