FIGURE 3.

p105 interacts with RelB in a distinct mode. A, cell extract from HeLa cells were used to immunoprecipitate RelB, p50, and RelA-bound p105 using RelB, p50, and RelA antibodies. The complexes were separated by SDS-PAGE followed by immunoblot with p105 antibody. B, in vitro GST pulldown experiments demonstrating the difference in the binding interaction between p100 CTD (IκBδ) and p105 CTD (IκBγ) with p52-RelB. Lane 8 demonstrates the lack of interaction of p105 CTD with p50/RelB versus the stable interaction between p100 CTD and p52-RelB (lane 10). Lanes 7 and 9 are positive controls of p105 CTD interacting with p50 and p100 CTD with p52, respectively. Lanes 1–6 show the inputs, and lanes 11–14 show the controls.