Figure 4

CRK9 interacts with cyclin B2. Recombinant GST-CRK9 was purified from transformed E. coli and incubated with the in vitro transcribed/translated HA-tagged cyclins E1 and B2, respectively. The GST protein complexes were bound to glutathione agarose, washed extensively, and analyzed by SDS PAGE followed by anti-HA Western blotting (top and central panels, as indicated) or total protein staining as loading controls (bottom panel). GST and glutathione beads without fused proteins attached served as negative controls.