Enzymatic activity was measured according to a previously reported method 28 . Briefly, Lα-phosphatidylinositol (Avanti Polar Lipid), dissolved in 3% n-octylglucoside (Roche Diagnostics), was used as the lipid substrate for the PI(4)K activity assay. PvPI(4)K was assayed using Transcreener ADP2 FP detection kit (BellBrook) in a black, solid 384-well plate (Corning). EC50 values were calculated from two independent experiments performed in duplicate using GraphPad Prism software.