Dissection of the LXXLL Nuclear Receptor-Coactivator Interaction Motif Using Combinatorial Peptide Libraries: Discovery of Peptide Antagonists of Estrogen Receptors α and β

作者：Ching‐yi Chang, John D. Norris, Hanne Grøn, Lisa A. Paige, Paul T. Hamilton, Daniel J. Kenan, Dana M. Fowlkes, Donald Patrick McDonnell · 发表于：Molecular and Cellular Biology · 年份：1999 · DOI：10.1128/mcb.19.12.8226 · 被引用次数：366 · 研究领域：Estrogen and related hormone effects、Receptor Mechanisms and Signaling、Monoclonal and Polyclonal Antibodies Research

Recruitment of transcriptional coactivators following ligand activation is a critical step in nuclear receptor-mediated target gene expression. Upon binding an agonist, the receptor undergoes a conformational change which facilitates the formation of a specific coactivator binding pocket within the carboxyl terminus of the receptor. This permits the alpha-helical LXXLL motif within some coactivators to interact with the nuclear receptors. Until recently, the LXXLL motif was thought to function solely as a docking module; however, it now appears that sequences flanking the core motif may play a role in determining receptor selectivity. To address this issue, we used a combinatorial phage display approach to evaluate the role of flanking sequences in influencing these interactions. We sampled more than 10(8) variations of the core LXXLL motif with estradiol-activated estrogen receptor alpha (ERalpha) as a target and found three different classes of peptides. All of these peptides interacted with ERalpha in an agonist-dependent manner and disrupted ERalpha-mediated transcriptional activity when introduced into target cells. Using a series of ERalpha-mutants, we found that these three classes of peptides showed different interaction patterns from each other, suggesting that not all LXXLL motifs are the same and that receptor binding selectivity can be achieved by altering sequences flanking the LXXLL core motif. Most notable in this regard was the discovery of a peptide which, wh...