Figure 4. L4-33K is phosphorylated by DNA-PK in a DNA-independent manner.

GST-p53 (lanes 1–3) and His-tagged L4-33K (lanes 4–6), L4-22K (lanes 7–9) and L4-33Kds were incubated in the presence (+) and absence (−) of DNA-PK and γ³²P ATP in the presence (+) and absence (−) of the DNA-PK activator, linear double stranded DNA (dsDNA). Phosphorylated proteins, detected as ³²P-labelled, were resolved by SDS-PAGE in 12% gels and incorporation of radiolabelled phosphate visualised by autoradiography (upper panel). Equal loading of each lane was verified by CBB staining (lower panel).