(A) Structures of relatively non-selective compounds that were, historically, used to inhibit PI4KIIIα, including phenylarsine oxide (PAO), Wortmannin, and Pik93. The IC50 values of Wortmannin, PAO and Pik93 for PI4KIIIα are referenced here, respectively[44,86,87]. PAO and wortmannin are broad-spectrum lipid kinase inhibitors, targeting PI 3-kinases and PI4KIIIα/β, whose kinase domains share homology with those of PI 3-kinases. Pik93 is more selective, inhibiting PI4KIIIα/β, with a higher affinity for the β form. (B) Structures of the recently developed, highly selective PI4KIIIα inhibitors AL-9, A1, C1, F1 and G1 with their IC50 values. Values in the standard font were measured with the ADP-Glo assay, and values in bold were measured by γ32 ATP PI-kinase assays[44].