Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.
Novartis-Berkeley Translational Chemical Biology Institute, Berkeley, California 94720, United States.
ACS Chem Biol. 2023 Apr 21;18(4):897-904. doi: 10.1021/acschembio.3c00040. Epub 2023 Mar 20.
Targeted protein degradation (TPD) with proteolysis targeting chimeras (PROTACs), heterobifunctional compounds consisting of protein targeting ligands linked to recruiters of E3 ubiquitin ligases, has arisen as a powerful therapeutic modality to induce the proximity of target proteins with E3 ligases to ubiquitinate and degrade specific proteins in cells. Thus far, PROTACs have primarily exploited the recruitment of E3 ubiquitin ligases or their substrate adapter proteins but have not exploited the recruitment of more core components of the ubiquitin-proteasome system (UPS). In this study, we used covalent chemoproteomic approaches to discover a covalent recruiter against the E2 ubiquitin conjugating enzyme UBE2D─EN67─that targets an allosteric cysteine, C111, without affecting the enzymatic activity of the protein. We demonstrated that this UBE2D recruiter could be used in heterobifunctional degraders to degrade neo-substrate targets in a UBE2D-dependent manner, including BRD4 and the androgen receptor. Overall, our data highlight the potential for the recruitment of core components of the UPS machinery, such as E2 ubiquitin conjugating enzymes, for TPD, and underscore the utility of covalent chemoproteomic strategies for identifying novel recruiters for additional components of the UPS.
靶向蛋白降解（TPD）利用蛋白水解靶向嵌合体（PROTACs），这是一种由蛋白质靶向配体与 E3 泛素连接酶招募器连接而成的双功能化合物，已成为诱导靶蛋白与 E3 连接酶接近以泛素化和降解细胞中特定蛋白质的强大治疗模式。到目前为止，PROTACs 主要利用 E3 泛素连接酶或其底物衔接蛋白的招募，但没有利用泛素-蛋白酶体系统（UPS）的更多核心组件的招募。在这项研究中，我们使用共价化学蛋白质组学方法来发现一种针对 E2 泛素结合酶 UBE2D─EN67─的共价招募器，该招募器针对别构半胱氨酸 C111，而不影响蛋白质的酶活性。我们证明，这种 UBE2D 招募器可用于双功能降解剂中，以依赖 UBE2D 的方式降解新的底物靶标，包括 BRD4 和雄激素受体。总的来说，我们的数据强调了招募 UPS 机械的核心组件（如 E2 泛素连接酶）用于 TPD 的潜力，并强调了共价化学蛋白质组学策略在鉴定 UPS 其他组件的新型招募器方面的实用性。
