Modulation of human nuclear receptor LRH-1 activity by phospholipids and SHPOrtlund, E.A., Lee, Y., Solomon, I.H., Hager, J.M., Safi, R., Choi, Y., Guan, Z., Tripathy, A., Raetz, C.R.H., McDonnell, D.P., Moore, D.D., Redinbo, M.R.
(2005) Nat Struct Mol Biol 12: 357-363
- PubMed: 15723037
- DOI: https://doi.org/10.1038/nsmb910
- Primary Citation of Related Structures:
- PubMed Abstract:
The human nuclear receptor liver receptor homolog 1 (hLRH-1) plays an important role in the development of breast carcinomas. This orphan receptor is efficiently downregulated by the unusual co-repressor SHP and has been thought to be ligand-independent. We present the crystal structure at a resolution of 1.9 A of the ligand-binding domain of hLRH-1 in complex with the NR box 1 motif of human SHP, which we find contacts the AF-2 region of hLRH-1 using selective structural motifs. Electron density indicates phospholipid bound within the ligand-binding pocket, which we confirm using mass spectrometry of solvent-extracted samples. We further show that pocket mutations reduce phospholipid binding and receptor activity in vivo. Our results indicate that hLRH-1's control of gene expression is mediated by phospholipid binding, and establish hLRH-1 as a novel target for compounds designed to slow breast cancer development.
Department of Chemistry, Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, 27599, USA.