FIGURE 6.

ATF3 via its basic region binds to the RING finger of MDM2. A, GST-MDM2 fusion proteins were immobilized on glutathione-agarose and incubated with in vitro translated ATF3 protein. After extensive washes, bound proteins were eluted, subjected to SDS-PAGE, and detected by immunoblotting. The lower panel shows Coomassie Blue staining of the fusion proteins. B, GST-ATF3 fusion proteins were immobilized and incubated with in vitro translated MDM2 as in A. The bound MDM2 protein was detected by immunoblotting. The lower panel shows Ponceau S staining of the blot.