Direct PKR-PKR interaction via aa 244 to 296. Increasing amounts (lanes 1 and 6, 10 ng; lanes 2 and 7, 20 ng; lanes 3 and 8, 30 ng; lanes 4 and 9, 40 ng; lanes 5 and 10, 50 ng) of purified bacterially expressed GST and GST-PKR(244–296) were subjected to SDS-PAGE and transferred to nitrocellulose. The filter was overlaid with radiolabeled PKR aa 1-to-242 (top), 244-to-551 (middle), or 296-to-551 probe (bottom) and subjected to autoradiography. Arrows indicate positions of GST fusion protein and GST alone.