ARIP3 enhances the sumoylation of AR and c-Jun in vitro. (A) Effect of ARIP3 on sumoylation of in vitro-translated AR. 35S-labeled, in vitro-translated AR was incubated with purified GST-SUMOGG-1 (in all reactions), GST-SAE1 plus GST-SAE2 (in all reactions), and GST-Ubc9 in the presence or absence of GST, GST-ARIP3, or GST-ARIP3Δ347-418 as indicated. Samples were resolved by SDS-PAGE and subjected to fluorography. (B) ARIP3 enhances the sumoylation of purified recombinant c-Jun. His-tagged c-Jun was incubated with GST-SUMOGG-1, GST-SAE1 plus GST-SAE2, and GST-Ubc9 in the presence of GST alone, GST-ARIP3, GST-ARIP3Δ347-418, GST-ARIP3(W383A), or GST-ARIP3Δ467-487 as indicated. Samples were resolved by SDS-PAGE and immunoblotted with the anti-His antibody. Arrowheads indicate sumoylated forms of proteins.