Modulation of nuclear receptor interactions by ligands: Kinetic analysis using surface plasmon resonance
Modulation of nuclear receptor interactions by ligands: Kinetic analysis using surface plasmon resonance
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DOI：
10.1021/bi952283r
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发表时间：
1996-03-12
期刊：
影响因子：
2.9
通讯作者：
Freedman, LP
中科院分区：
文献类型：
--
作者：
Cheskis, B;Freedman, LP
许多核激素受体，包括人1，25-二羟基维生素D-3受体（VDR），与9-顺式-视黄酸受体（RXR）以同源二聚体或异源二聚体的形式协同结合DNA。由DNA和配体结合结构域内的残基介导的蛋白质-蛋白质相互作用有助于这种结合。我们先前已经报道了VDR和RXR的配体可以调节受体与DNA相互作用的亲和力[Cheskis，B.，和弗里德曼，L。P.（1994）Mol. Cell. 14，3329-3338]。为了更详细地研究这一点，我们在这里报告使用表面等离子体共振（SPR）来表征VDR和RXR在存在和不存在其同源配体的情况下的蛋白质-蛋白质和蛋白质-DNA相互作用的动力学。我们发现，1，25二羟维生素D-3结合有利于VDR-RXR异源二聚化，因此。复合物结合DNA。相反，配体降低溶液中的VDR同源二聚化和VDR-DNA相互作用的亲和力。9-顺式-视黄酸通过降低VDR-RXR异源二聚体形成的速率并同时通过增加RXR同二聚化的亲和力来减弱1，25-二羟基维生素D-3的刺激作用。因此，使用SPR，我们已经表明，这样的配体的主要作用是调节核受体二聚化在溶液中和DNA上。配体似乎动态地这样做，调节这些复合物的总体亲和力。因此，这种机制创造了一种快速和灵敏的方式来调节DNA结合，以响应配体浓度的变化。
Many nuclear hormone receptors, including the human 1,25-dihydroxyvitamin D-3 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 D-3 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 acid attenuates the stimulating effect of 1,25-dihydroxyvitamin D-3 by decreasing the rate of VDR-RXR heterodimer formation and simultaneously by increasing the affinity of RXR homodimerization. Thus, using SPR, we have shown that a major role for such ligands is to regulate nuclear receptor dimerization both in solution and on DNA. The ligands appear to do so dynamically, modulating the overall affinity of these complexes. This mechanism therefore creates a fast and sensitive way to regulate DNA binding in response to changes in ligand concentration.