IC50 values (± Standard Error, logEC50) were determined for staurosporine, wortmannin, CC004731 and CC004733 for the mitotic kinases Nek2, Nek6, Nek7, Aurora A, Plk1 and Cdkl/Cyclin B in a biochemical kinase assay. >400 μM denotes no inhibition at 400 μM inhibitor, the highest concentration used in the assay.