Fig. 1. Interaction between c-Abl and Hdm2 in vitro and in vivo. (A) 293 cells were transfected with the indicated expression plasmids (5 µg each). Twenty-four hours post-transfection, cell extracts were subjected to immunoprecipitation using anti-c-Abl antibody (ABL-148) followed by western blotting using anti-Hdm2 (SMP14) (I). The expression level of Hdm2 in the transfected cells was monitored by blotting with anti-Hdm2 antibody (SMP14) (II), and that of c-Abl using anti-c-Abl antibody (ABL-148) (III). (B) Radioactively labeled ([³⁵S]methionine) Mdm2 and c-Abl were incubated in vitro before being subjected to immunoprecipitation using anti-Hdm2 antibody (2A10). The amount of bound c-Abl was detected by exposure to film. As a control, unlabeled c-Abl was used (lane 5). The amount of input for each protein is shown (lanes 1 and 2).