Potent acyl CoA synthetase 10 inhibitors disrupt triglyceride formation in P. falciparum

Identifying how small molecules that kill malaria parasites work can lead to new, “chemically validated” targets. Selections with three novel structurally-unrelated compounds (MMV665924, MMV019719 and MMV897615) revealed that compound-resistant parasites carried one of seven different mutations in the Plasmodium falciparum acyl-CoA synthetase (ACS) genes PfACS10 (PF3D7_0525100, M300I, A268D/V, F427L) and PfACS11 (PF3D7_1238800, F387V, D648Y, and E668K). We validated PfACS10 as a target of these compounds by allelic replacement and thermal proteome profiling. We demonstrated that PfACS10 is essential for parasite growth by conditional knockdown and shows increased compound susceptibility under low PfACS10 levels. Inhibition of PfACS10 leads to a reduction in triacylglycerols and a buildup of its lipid precursors. Allelic replacement of mutations in PfACS11 phenocopy the selected lines, however, conditional knockdown demonstrates that PfACS11 is not essential for parasite growth. Together, these results imply PfACS10 as the direct target and PfACS11 as mediating resistance.