(A) Kinase assays were performed using material precipitated with PSKH2 from HEK-293T cells in the presence of ATP-γ-S. Protein phosphorylation as a consequence of kinase activity was detected using an antibody with specificity towards thiophosphate esters (Thio-P), and is compared with precipitations from cells overexpressing EGFP, WT PSKH2, or ‘canonical’ amino acid changing variants of PSKH2 in the absence or (B) presence of the indicated polypeptide substrate. PKA, Aurora A (AURA) and casein kinase 2 (CK2) were used as positive controls for auto- and substrate phosphorylation.