Non-steroid receptors
Thyroid hormone receptor (TR), vitamin D receptor, retinoic acid receptor (RAR), peroxisome proliferator-activated receptor (PPAR), and liver oxysterol receptor (LXR) are examples of receptors belonging to the nuclear receptor subgroup type II. These receptors are always localized in the nucleus regardless of the ligand binding status.
In contrast to the steroid receptors, they bind DNA as heterodimers, usually with
RAR. In contrast to the steroid receptors, ligand-free type II nuclear receptors form complexes repressor proteins (red TF). Ligand binding to the nuclear receptor causes dissociation of repressor protein and recruitment of activator proteins (green TF).
Other receptors from this group bind lipids, prostaglandins, non-steroidal drugs, fibrates and thiazolidinediones.
