FIG. 15.

Model for transcriptional activation of nuclear hormone receptors by NRC. The LXXLL-1 motifs of NRC dimers interact with the hydrophobic grooves of ligand-bound receptor homo- or heterodimers. This results in a conformational change in NRC which may expose an activation domain(s), which leads to transcriptional activation. The finding that NRC interacts with CBP in the apparent absence of ligand (Fig. 14A) suggests that a preformed complex of NRC and CBP binds receptors. This model does not exclude the possibility that other factors or metabolic processes influence the association of hNRC with CBP.