Identification of Antimalarial Compounds that Inhibit Apicomplexan AP2 Proteins

Abstract

Plasmodium parasites are reliant on the Apicomplexan AP2 (ApiAP2) transcription factor family to regulate gene expression programs. The AP2 DNA binding domains have no homology to the human or mosquito hosts, making them potential drug targets. Using an in-silico screen to dock thousands of small molecules into the crystal structure of the AP2-EXP (Pf3D7_1466400) AP2 domain (PDB:3IGM), we identified compounds that interact with this domain. Four compounds were found to compete for DNA binding with AP2-EXP and at least one additional ApiAP2 protein. Our top ApiAP2 competitor compound perturbs the transcriptome of P. falciparum trophozoites and results in a decrease in abundance of log2 fold change > 2 for 50% (46/93) of AP2-EXP target genes identified. Additionally, two ApiAP2 competitor compounds have anti- Plasmodium activity against P. berghei mosquito stage parasites. In summary, we describe a novel set of antimalarial compounds that are targeted against the ApiAP2 family of proteins. These compounds may be used for future chemical genetic interrogation of ApiAP2 proteins or serve as starting points for a new class of antimalarial therapeutics.

AP2XII-2 coordinates transcriptional repression forToxoplasma gondiisexual commitment

“…Here we have begun unravelling one of the networks responsible for this process by placing the AP2XII-2-directed HDAC3/MORC complex above two genes that function in sexual stages, AP2X-10 and AAH1. In addition to utilizing a candidate-based approach as we have relied on for this study, the recent report highlighting inhibitors of AP2-family member activity may prove yet another tool for interrogating the role of AP2 factors in Toxoplasma developmental transitions (35).…”

DNA sequence context and the chromatin landscape differentiate sequence-specific transcription factor binding in the human malaria parasite,Plasmodium falciparum

“…We also investigated two additional TFs, PF3D7_1222600 (PfAP2-G) 83,94 and PF3D7_1466400 (PfAP2-EXP) 95 (Figure 1A). PfAP2-G and PfAP2-EXP were included in this study to dissect the mechanisms driving the overlap of in vivo binding sites through TFs that recognize divergent in vitro DNA motifs.…”

“…PfAP2-G and PfAP2-EXP were included in this study to dissect the mechanisms driving the overlap of in vivo binding sites through TFs that recognize divergent in vitro DNA motifs. Based on comparisons of published in vivo binding site data from chromatin immunoprecipitation followed by sequencing (ChIP-seq) studies, PfAP2-G and PfAP2-EXP recognize unique DNA motifs yet occupy a subset of overlapping genomic regions with PfAP2-I 83,95 . PfAP2-G (Gametocytogenesis) is a master regulator of sexual stage commitment and binds a GTAC DNA motif both in vitro and in vivo 43,83,94 .…”

“…PfAP2-G (Gametocytogenesis) is a master regulator of sexual stage commitment and binds a GTAC DNA motif both in vitro and in vivo 43,83,94 . PfAP2-EXP (Exported Proteins) recognizes a TGCATGCA DNA motif through in vitro and in vivo binding assays, including a high-resolution structural study 62,95,96 . While overlapping genomic binding sites have been reported for a number of TFs in P. falciparum 71,83,95,97 , the mechanisms that drive these shared binding events are not well understood.…”