Androgen receptor, allosteric sites (AR)

The **Androgen receptor (AR)** is a nuclear receptor transcription factor that governs gene expression in response to androgenic hormones, including testosterone and dihydrotestosterone. AR has a modular structure consisting of an N-terminal domain (NTD), a DNA-binding domain (DBD), a hinge region, and a C-terminal ligand-binding domain (LBD) with several known canonical and allosteric regulatory surfaces. Allosteric sites—such as BF-3 and other recently described surfaces—do not bind classical ligands but instead regulate receptor structure and function, potentially modulating AR activity in diseases such as prostate cancer and androgen insensitivity syndromes. Mutations at these sites, as well as their functional coupling with canonical coactivator binding pockets (like AF-2), alter receptor conformation and downstream transcriptional activity. These sites are considered attractive for drug discovery, offering alternatives to ligand-competitive antagonists, particularly in hormone-refractory cancers. Drugs targeting AR, including both classical anti-androgens and allosteric modulators, inhibit AR-driven gene expression, cell proliferation, and cancer growth. Key therapeutic challenges include resistance arising from AR mutation, amplification, and splice variation, as well as safety concerns involving disruption of normal androgen physiology.

Other names

NR3C4Androgen nuclear receptorTestosterone receptor

Antagonism of canonical ligand-binding domain (LBD) Allosteric modulation of non-canonical surface pockets, including BF-3 and other allosteric sites, affecting AR conformation and function Inhibition of receptor nuclear translocation or DNA binding