Plasmodium SEY1 is a novel druggable target that contributes to imidazolopiperazine mechanism of action.

The precise mode of action of ganaplacide (KAF156), a phase III antimalarial candidate, remains elusive. Here we employ omics-based methods with the closely related chemical analog, GNF179, to search for potential targets. Ranking potential targets derived from chemical genetics and proteomic affinity chromatography methodologies identifies , or Synthetic Enhancement of YOP1, which is predicted to encode an essential dynamin-like GTPase implicated in homotypic fusion of endoplasmic reticulum (ER) membranes. We demonstrate that GNF179 decreases SEY1 melting temperature. We further show that GNF179 binds to recombinant SEY1 and subsequently inhibits its GTPase activity, which is required for maintaining ER architecture. Using ultrastructure expansion microscopy, we find GNF179 treatment changes parasite ER and Golgi morphology. We also confirm that is an essential gene in . These data suggest that may contribute to the mechanism of action of imidazolopiperazines and is a new and attractive druggable target.