Genetic ablation of plasmoDJ1, a multi-activity enzyme, attenuates parasite virulence and reduces oocyst production

Malaria parasites must respond to stresses and environmental signals to perpetuate efficiently during their multi-stage development in diverse environments. To gain insights into the parasite’s stress response mechanisms, we investigated a conserved Plasmodium protein, which we have named plasmoDJ1 based on the presence of a putative cysteine protease motif of the DJ-1/PfpI superfamily, for its activities, potential to respond to stresses, and role in parasite development. PlasmoDJ1 is expressed in all intraerythrocytic stages and ookinetes. Its expression was increased 7-9 times upon heat shock and oxidative stress due to H2O2 and artemisinin; its expression in a stress sensitive E. coli mutant conferred tolerance against oxidative stress, indicating that plasmoDJ1 has potential to sense and/or protect from stresses. Recombinant plasmoDJ1 efficiently neutralized H2O2, facilitated renaturation of denatured citrate synthase, and showed protease activity, indicating that plasmoDJ1 is a multi-activity protein. Mutation of the catalytic cysteine, but not other residues, reduced H2O2-neutralization activity by ~90% and significantly decreased chaperone and protease activities, indicating that these activities are intrinsic to plasmoDJ1. The plasmoDJ1 gene knockout in P. berghei ANKA attenuated virulence and reduced oocyst production, suggesting a major role of plasmoDJ1 in parasite development, which most likely depends on its multiple activities.
Source: BJ Cell - Category: Biochemistry Authors: Tags: BJ Cell Source Type: research