Fig 8.

The 156R splice product of E1B-55K is also phosphorylated by CK2α but not by the holoenzyme. The indicated GST-E1B and GST-April fusion proteins were incubated either with recombinant CK2α or CK2 holoenzyme together with radioactive [γ-³²P]ATP for 30 min at 30°C. Where indicated, CK2α batches were incubated for 15 min in 20 μM DMAT together with substrates at room temperature prior to starting the in vitro kinase reaction. Kinase assay products were analyzed by SDS-PAGE, and the gels were Coomassie stained (“safe stain,” lower panels) and then vacuum dried for autoradiography on X-ray films (top panels). Additional control lanes were omitted due to clarity. Segments are from the same autoradiograph. The autoradiograph represents one of at least three independent experiments.