To determine the role of the capping triad on malaria parasite development, we utilized a chemical genetic approach employing a selective PKG inhibitor (compound 2, an imidazopyridine) and a transgenic parasite line expressing an engineered PKG allele (incorporating a threonine to glutamine substitution, T618Q) that confers inhibitor resistance [6–8,21]. Here, PRKG1 is linked to malaria.