ABSTRACT:
Protein arginine methyltransferases (PRMTs) play critical roles in
Plasmodium falciparum
, a protozoan causing the deadliest form of malaria, making them potential targets for novel antimalarial drugs. Here, we screened 11 novel PRMT inhibitors against
P. falciparum
asexual growth and found that onametostat, an inhibitor for type II PRMTs, exhibited strong antimalarial activity with a half-maximal inhibitory concentration (IC
50
) value of 1.69 ± 0.04 µM.
In vitro
methyltransferase activities of purified PfPRMT5 were inhibited by onametostat, and a shift of IC
50
to onametostat was found in the
PfPRTM5
disruptant parasite line, indicating that PfPRTM5 is the primary target of onametostat. Consistent with the function of PfPRMT5 in mediating symmetric dimethylation of histone H3R2 (H3R2me2s) and in regulating invasion-related genes, onametostat treatment led to the reduction of H3R2me2s level in
P. falciparum
and caused the defects on the parasite’s invasion of red blood cells. This study provides a starting point for identifying specific PRMT inhibitors with the potential to serve as novel antimalarial drugs.