The 26S proteasome is involved in degrading and regulating the majority of proteins in eukaryotic cells, which requires a sophisticated balance of specificity and promiscuity. In this Review, we discuss the principles that underly substrate recognition and ATP-dependent degradation by the proteasome. We focus on recent insights into the mechanisms of conventional ubiquitin-dependent and ubiquitin-independent protein turnover, and discuss the plethora of modulators for proteasome function, including substrate-delivering cofactors, ubiquitin ligases and deubiquitinases that enable the targeting of a highly diverse substrate pool. Furthermore, we summarize recent progress in our understanding of substrate processing upstream of the 26S proteasome by the p97 protein unfoldase. The advances in our knowledge of proteasome structure, function and regulation also inform new strategies for specific inhibition or harnessing the degradation capabilities of the proteasome for the treatment of human diseases, for instance, by using proteolysis targeting chimera molecules or molecular glues.

26S 蛋白酶体参与降解和调节真核细胞中的大多数蛋白质，这需要特异性和混杂性的复杂平衡。在这篇综述中，我们讨论了蛋白酶体对底物识别和 ATP 依赖性降解的原理。我们重点介绍了对常规泛素依赖性和泛素非依赖性蛋白质周转机制的最新见解，并讨论了蛋白酶体功能的大量调节剂，包括底物递送辅因子、泛素连接酶和去泛素酶，它们能够靶向高度多样化的底物库。此外，我们总结了我们对 p97 蛋白去折叠酶在 26S 蛋白酶体上游的底物加工的理解的最新进展。我们对蛋白酶体结构、功能和调节知识的进步也为特异性抑制或利用蛋白酶体的降解能力治疗人类疾病的新策略提供了信息，例如，通过使用靶向嵌合体分子或分子胶的蛋白水解。