Current efforts in the proteolysis targeting chimera (PROTAC) field mostly focus on choosing an appropriate E3 ligase for the target protein, improving the binding affinities towards the target protein and the E3 ligase, and optimizing the PROTAC linker. However, due to the large molecular weights of PROTACs, their cellular uptake remains an issue. Through comparing how different warhead chemistry, reversible noncovalent (RNC), reversible covalent (RC), and irreversible covalent (IRC) binders, affects the degradation of Bruton Tyrosine Kinase (BTK), we serendipitously discovered that cyano-acrylamide-based reversible covalent chemistry can significantly enhance the intracellular accumulation and target engagement of PROTACs and developed RC 1 as the first reversible covalent BTK PROTAC with a high target occupancy as its corresponding kinase inhibitor and effectiveness as a dual functional inhibitor/degrader, a novel mechanism-of-action for PROTACs. Importantly, this reversible covalent strategy is generalizable to improve other PROTACs, opening a new path to enhance PROTAC efficacy.

中文翻译：

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可逆共价化学增强PROTAC的细胞内积累和靶标参与

在蛋白水解靶向嵌合体（PROTAC）领域中的当前努力主要集中在为靶蛋白选择合适的E3连接酶，改善对靶蛋白和E3连接酶的结合亲和力以及优化PROTAC接头。然而，由于PROTAC的分子量大，它们的细胞摄取仍然是一个问题。通过比较不同的战斗部化学性质，可逆非共价（RNC），可逆共价（RC）和不可逆共价（IRC）结合剂如何影响Bruton酪氨酸激酶（BTK）的降解，我们偶然发现基于氰基丙烯酰胺的可逆共价化学物质可显着增强PROTAC的细胞内积累和靶标结合，并开发出RC 1作为首个可逆共价BTK PROTAC，具有较高的靶标占有率作为其相应的激酶抑制剂，并具有双重功能抑制剂/降解剂，PROTAC的新型作用机理。重要的是，这种可逆的共价策略可推广用于改善其他PROTAC，为增强PROTAC效力开辟了一条新途径。