Deciphering the allosteric control of androgen receptor DNA binding by its disordered N-terminal domain.

Abstract

The androgen receptor (AR) plays a pivotal role in male physiological development and is implicated in the pathogenesis of various diseases, including prostate cancer. Its N-terminal domain (NTD), characterized by intrinsic disorder, is essential for transcriptional activation. Despite its importance, the precise mechanisms by which the NTD regulates AR's DNA-binding activity remain incompletely understood. This research elucidates the allosteric control mediated by specific NTD subregions-the N-terminal region (NR) and the C-terminal region (CR)-over the DNA binding properties of a truncated AR construct comprising the DNA-binding and ligand-binding domains (ΔNTD-AR). Microscale Thermophoresis (MST) and single-molecule fluorescence imaging were employed to investigate these interactions. This study demonstrates that the NTD subregions exert differential modulatory effects on the kinetics and affinity of ΔNTD-AR binding to DNA. MST analyses indicated that CR reduces ΔNTD-AR DNA binding affinity concentration-dependently, whereas NR did not significantly alter affinity. Single-molecule investigations revealed NR accelerates dissociation, while CR markedly diminishes binding frequency and accelerates dissociation. Combined NR and CR exerted complex effects, synergistically reducing affinity at high concentrations and altering kinetics distinctively compared to individual subregions. Collectively, these results delineate distinct functional roles for the NR and CR subregions in allosterically modulating AR-DNA interactions. This detailed understanding of intrinsic AR regulation offers mechanistic insights into receptor function and highlights potential allosteric sites for therapeutic intervention.