Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.
Novartis-Berkeley Center for Proteomics and Chemistry Technologies, Berkeley, California 94720, United States.
J Am Chem Soc. 2022 Jan 19;144(2):701-708. doi: 10.1021/jacs.1c03980. Epub 2022 Jan 7.
Proteolysis-targeting chimeras (PROTACs), heterobifunctional compounds that consist of protein-targeting ligands linked to an E3 ligase recruiter, have arisen as a powerful therapeutic modality for targeted protein degradation (TPD). Despite the popularity of TPD approaches in drug discovery, only a small number of E3 ligase recruiters are available for the >600 E3 ligases that exist in human cells. Here, we have discovered a cysteine-reactive covalent ligand, EN106, that targets FEM1B, an E3 ligase recently discovered as the critical component of the cellular response to reductive stress. By targeting C186 in FEM1B, EN106 disrupts recognition of the key reductive stress substrate of FEM1B, FNIP1. We further establish that EN106 can be used as a covalent recruiter for FEM1B in TPD applications by demonstrating that a PROTAC linking EN106 to the BET bromodomain inhibitor JQ1 or the kinase inhibitor dasatinib leads to the degradation of BRD4 and BCR-ABL, respectively. Our study showcases a covalent ligand that targets a natural E3 ligase-substrate binding site and highlights the utility of covalent ligand screening in expanding the arsenal of E3 ligase recruiters suitable for TPD applications.
蛋白水解靶向嵌合体（PROTACs）是一种由靶向蛋白配体与 E3 连接酶招募物连接而成的杂双功能化合物，已成为靶向蛋白降解（TPD）的一种强大治疗模式。尽管 TPD 方法在药物发现中很受欢迎，但在人类细胞中存在的 >600 种 E3 连接酶中，只有少数 E3 连接酶招募物可用。在这里，我们发现了一种半胱氨酸反应性共价配体 EN106，它靶向 FEM1B，这是一种最近被发现的 E3 连接酶，是细胞对还原应激反应的关键组成部分。通过靶向 FEM1B 的 C186，EN106 破坏了 FEM1B 对关键还原应激底物 FNIP1 的识别。我们通过证明将 EN106 与 BET 溴结构域抑制剂 JQ1 或激酶抑制剂 dasatinib 连接的 PROTAC 分别导致 BRD4 和 BCR-ABL 的降解，进一步证实了 EN106 可作为 TPD 应用中 FEM1B 的共价招募物。我们的研究展示了一种靶向天然 E3 连接酶-底物结合位点的共价配体，并强调了共价配体筛选在扩展适用于 TPD 应用的 E3 连接酶招募物武器库方面的实用性。
