Download MendeleyStructural and biochemical basis for selective repression of the orphan nuclear receptor liver receptor homolog 1 by small heterodimer partner.
Li, Y., Choi, M., Suino, K., Kovach, A., Daugherty, J., Kliewer, S.A., Xu, H.E.(2005) Proc Natl Acad Sci U S A 102: 9505-9510
- PubMed: 15976031
- DOI: https://doi.org/10.1073/pnas.0501204102
- Primary Citation of Related Structures:
1ZGY, 1ZH7 - PubMed Abstract:
The functional interaction between the orphan nuclear receptors small heterodimer partner (SHP) and liver receptor homolog 1 (LRH-1), where SHP binds to LRH-1 and represses its constitutive transcriptional activity, is crucial for regulating genes involved in cholesterol homeostasis. Here, we report structural and biochemical analyses of the LRH-1/SHP interaction. The crystal structure and modeling studies of the LRH-1 ligand-binding domain bound to either of the two LXXLL-related motifs of SHP show that the receptor undergoes conformational changes to accommodate the SHP docking and reveal key residues that determine the potency and selectivity of SHP binding. Through a combination of mutagenesis and binding studies, we demonstrate that only the second SHP LXXLL motif is required for repressing LRH-1, and this motif displays a strong preference for binding to LRH-1 over the closely related receptor steroidogeneic factor 1 (SF-1). Structural comparisons indicate that this binding selectivity is determined by residues flanking the core LXXLL motifs. These results establish a structural model for understanding how SHP interacts with LRH-1 to regulate cholesterol homeostasis and provide new insights into how nuclear receptor/coregulator selectivity is achieved.
Organizational Affiliation:
Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Avenue, Grand Rapids, MI 49503, USA.
