Imaging of Selective Nuclear Receptor Modulator-Induced Conformational Changes in the Nuclear Receptor to Allow Interaction with Coactivator and Corepressor Proteins in Living Cells

Authors

  • Muhammad Awais Dr.,

    1. Department of Molecular Structure, Institute for Molecular Science, 38 Nishigonaka, Myodaiji, Okazaki, Japan
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  • Moritoshi Sato Dr.,

    1. Department of Chemistry, School of Science, The University of Tokyo and Japan Science and Technology (JST), Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Fax: (+81) 3-5841-8349
    2. PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama, Japan
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  • Yoshio Umezawa Prof.

    1. Department of Chemistry, School of Science, The University of Tokyo and Japan Science and Technology (JST), Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Fax: (+81) 3-5841-8349
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Abstract

Selective nuclear receptor modulators (SNRMs), which are used clinically for the treatment of NR-related diseases, display mixed agonistic/antagonistic activity in a tissue-selective manner depending on the cellular concentrations of coregulator proteins, that is, coactivators and corepressors. The molecular details of the SNRM function provided us with an idea for a rational method for the high-throughput screening of SNRMs in real time in intact living cells. We have developed genetically encoded fluorescent indicators based on the principle of ligand-induced coactivator and/or corepressor recruitment to NR ligand binding domain in single living cells. We demonstrated that an SNRM induces a distinct conformational change in the NR LBD, which is different from that induced by a full agonist or antagonist, but favorable for the recruitment of a coactivator or corepressor protein to the NR. The molecular details of an SNRM binding to a NR, and the subsequently induced conformational changes and recruitment of coregulator protein(s) are important features for the understanding of SNRM action in the living body. Our fluorescent indicators are capable of distinguishing among agonists, antagonists, and SNRMs, and can therefore serve as versatile molecular sensors that predict the pharmacological character of ligands, which is important for an accurate cure of a disease.

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