Modulation of Nuclear Receptor Interactions by Ligands: Kinetic Analysis Using Surface Plasmon Resonance†

TLDR: Cheskis et al. as discussed by the authors used surface plasmon resonance (SPR) to characterize the kinetics of both protein−protein and protein−DNA interactions by VDR and RXR in the presence and absence of their cognate ligands.

Abstract: Many nuclear hormone receptors, including the human 1,25-dihydroxyvitamin D3 receptor (VDR), bind cooperatively to DNA as either homodimers or heterodimers with the 9-cis-retinoic acid receptor (RXR). Protein−protein interactions mediated by residues within both the DNA- and ligand-binding domains contribute to this binding. We have previously reported that the ligands for VDR and RXR can modulate the affinity of the receptors' interaction with DNA [Cheskis, B., & Freedman, L. P. (1994) Mol. Cell. Biol. 14, 3329−3338]. To examine this in more detail, we report here the use of surface plasmon resonance (SPR) to characterize the kinetics of both protein−protein and protein−DNA interactions by VDR and RXR in the presence and absence of their cognate ligands. We find that 1,25 dihydroxyvitamin D3 binding favors both VDR−RXR heterodimerization and, as a result, DNA binding by the complex. Conversely, the ligand reduces VDR homodimerization in solution and the affinity of VDR−DNA interaction. 9-cis-Retinoic aci...