“…NRs are a superfamily of ligand-dependent transcriptional factors containing n N-terminal transactivation domain, a flexible hinge region, and a C-terminal ligand-binding domain (LBD) [6,8,13]. NRs are classified mainly into two types according to their subcellular distribution in the absence of a ligand and their mechanisms: Type I steroid receptors, including the estrogen receptor (ER), androgen receptor (AR), progesterone receptor (PR), and glucocorticoid receptor (GR); and Type II nonsteroid receptors, including the thyroid receptor (TR alpha and beta), retinoic acid receptor (RAR alpha, beta, and gamma), retinoid X receptor (RXR), vitamin D receptor (VDR), peroxisome proliferator-activated receptor (PPAR alpha, beta, and gamma), liver X receptor (LXR), farnesoid X receptor (FXR), and pregane X receptor (PXR), [6,14,15]. In the absence of a ligand, the type I NR forms inactive complexes with chaperone proteins in the cytoplasm, whereas type II NR, regardless of the ligand-binding status, is located in the nucleus and binds to the DNA response elements of its target genes along with corepressors [6,14,16].…”