FIG. 4.

Increased nuclear propensity of p50–c-Rel heterodimers. Left panels show the subcellular distribution of homodimers of GFP-p65 (first row), an NES-mutated GFP-p65 (second row), and GFP-c-Rel (third row) in the presence of HA-IκBαNESn (IκBα mutated in the N-terminal NES). Right panels show the distribution of heterodimers of these Rel proteins together with p50 in the presence of HA-IκBαNESn. In all cases, GFP fluorescence colocalized with anti-HA, indicating that IκBα was associated with the Rel homo- or heterodimers. All complexes were predominantly nuclear when the cells were treated with LMB for the last 3 h prior to harvest (data not shown). Results shown are from one of three independent experiments.