Aspartyl protease 5 matures dense granule proteins that reside at the host-parasite interface in toxoplasma gondii

Abstract

Toxoplasma gondii infects approximately 30% of the world’s population, causing disease primarily during pregnancy and in individuals with weakened immune systems. Toxoplasma secretes and exports effector proteins that modulate the host during infection, and several of these proteins are processed by the Golgi-associated aspartyl protease 5 (ASP5). Here, we identify ASP5 substrates by selec-tively enriching N-terminally derived peptides from wild-type and Δasp5 parasites. We reveal more than 2,000 unique Toxoplasma N-terminal peptides, mapping to both natural N termini and protease cleavage sites. Several of these peptides mapped directly downstream of the characterized ASP5 cleavage site, ar..