Looking at nuclear receptors from a new angle.

Area of Science:

• Molecular Biology
• Structural Biology
• Biochemistry

Background:

• Nuclear receptors (NRs) are crucial transcription factors regulating gene expression.
• While DNA-binding and ligand-binding domains are well-characterized, their interaction mechanisms remain unclear.
• Understanding NR domain communication is key to deciphering their regulatory functions.

Purpose of the Study:

• To investigate the structural basis of communication between DNA- and ligand-binding domains in nuclear receptors.
• To elucidate the role of novel interaction surfaces in allosteric signaling.
• To reconcile conflicting structural data regarding receptor conformation.

Main Methods:

• X-ray crystallography of receptor dimers bound to DNA, ligands, and coactivator peptides.
• Structural analysis of DNA-bound receptor dimers in solution.
• Comparative analysis of distinct structural conformations.

Main Results:

• First crystal structures of NR dimers bound to DNA, ligand, and coactivator peptides revealed new interaction surfaces.
• These interfaces are proposed as pathways for allosteric signal transmission from DNA to the ligand-binding domain.
• Solution structures of DNA-bound dimers showed an extended conformation, contrasting with crystal data.

Conclusions:

• Novel interaction interfaces between NR domains facilitate allosteric communication.
• Contradictory structural data suggest conformational flexibility is essential for NR function.
• These findings provide insights into the dynamic mechanisms governing nuclear receptor activity.