PIK-93 is a PI4KIIIβ inhibitor (IC50 at 19 nM). PIK-93 is the first reported PI4-kinase inhibitor, which is able to inhibit PI4KIIIβ at low-nanomolar range. In addition, PIK-93 also inhibits potently PI3Kγ in vitro (IC50 at 16 nM). PIK-93 inhibits p110α, p110β, p110δwith IC50 of 0.039, 0.59, 0.12 μM. PIK-93 also displays the typical hydrogen bonding to the backbone amide of Val882, and additional ones to the backbone carbonyl of Val882 and between its sulphonamide and Asp964.