FIG. 2.

RB C-pocket mutants do not inhibit c-Abl kinase activity. The indicated GST-RB C-terminal proteins purified from bacteria were incubated with in vitro-translated c-Abl. The c-Abl proteins from these incubations were then subjected to an immune-complex kinase assay, with a GST-CTD fusion protein as the substrate. Phosphorylated CTD was detected by autoradiography (A). The immune complex was also subjected to anti-Abl immunoblot analysis (B) to measure the relative amount of in vitro-translated c-Abl in each reaction. The amount of GST-RB protein present in each reaction mixture was visualized by amido black staining of the nitrocellulose membrane after transfer (C). See Fig. 1 for explanations of the RB fragments.