FIG. 6.

Phosphorylation of Gro/TLEs by protein kinase CK2. Lysates from either Drosophila S2 (A and B) or human Jurkat (C) cells were subjected to immunoprecipitation with anti-Gro (A and B, lanes 1 to 3), anti-Gro/TLE1 (C, lanes 1 and 2), or control (C, preim. serum, lane 3) antibodies. Immunoprecipitates were extensively washed, followed by incubation with [γ-³²P]ATP in the presence or absence of purified protein kinase CK2, as indicated. Samples were then subjected to SDS-PAGE, transfer to nitrocellulose, and autoradiography. In panel B, autoradiography was followed by Western blotting with anti-Gro antibodies. Gro/TLEs were phosphorylated in vitro by purified protein kinase CK2.