Hsp70 and Hsp40 inhibit an inter-domain interaction necessary for transcriptional activity in the androgen receptor

Nat Commun. 2019 Aug 8;10(1):3562. doi: 10.1038/s41467-019-11594-y.

Abstract

Molecular chaperones such as Hsp40 and Hsp70 hold the androgen receptor (AR) in an inactive conformation. They are released in the presence of androgens, enabling transactivation and causing the receptor to become aggregation-prone. Here we show that these molecular chaperones recognize a region of the AR N-terminal domain (NTD), including a FQNLF motif, that interacts with the AR ligand-binding domain (LBD) upon activation. This suggests that competition between molecular chaperones and the LBD for the FQNLF motif regulates AR activation. We also show that, while the free NTD oligomerizes, binding to Hsp70 increases its solubility. Stabilizing the NTD-Hsp70 interaction with small molecules reduces AR aggregation and promotes its degradation in cellular and mouse models of the neuromuscular disorder spinal bulbar muscular atrophy. These results help resolve the mechanisms by which molecular chaperones regulate the balance between AR aggregation, activation and quality control.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Androgens / metabolism*
  • Animals
  • Gene Knock-In Techniques
  • HEK293 Cells
  • HSP40 Heat-Shock Proteins / metabolism*
  • HSP70 Heat-Shock Proteins / metabolism*
  • Humans
  • Ligands
  • Male
  • Mice
  • Mice, Transgenic
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Aggregates
  • Protein Domains
  • Protein Multimerization
  • Receptors, Androgen / chemistry
  • Receptors, Androgen / genetics
  • Receptors, Androgen / metabolism*
  • Solubility

Substances

  • AR protein, human
  • Androgens
  • DNAJA2 protein, human
  • HSP40 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins
  • HSPA1A protein, human
  • Ligands
  • Protein Aggregates
  • Receptors, Androgen