Cyclin-dependent kinases (CDKs) are activated by cyclins, which play important roles in dictating the actions of CDK/cyclin complexes. Cyclin binding influences the substrate specificity of these complexes in addition to their susceptibility to inhibition or degradation. CDK/cyclin complexes are best known to promote cell cycle progression in the mitotic cell cycle but are also crucial for important cellular processes not strictly associated with cellular division. This chapter primarily explores the understudied topic of CDK/cyclin complex functionality during the DNA damage response. We detail how CDK/cyclin complexes perform dual roles both as targets of DNA damage checkpoint signaling as well as effectors of DNA repair. Additionally, we discuss the potential CDK-independent roles of cyclins in these processes and the impact of such roles in human diseases such as cancer. Our goal is to place the spotlight on these important functions of cyclins either acting as independent entities or within CDK/cyclin complexes which have attracted less attention in the past. We consider that this will be important for a more complete understanding of the intricate functions of cell cycle proteins in the DNA damage response.

细胞周期蛋白依赖性激酶 (CDK) 被细胞周期蛋白激活，其在决定 CDK/细胞周期蛋白复合物的作用中起重要作用。除了它们对抑制或降解的敏感性之外，细胞周期蛋白结合还会影响这些复合物的底物特异性。众所周知，CDK/细胞周期蛋白复合物可促进有丝分裂细胞周期中的细胞周期进程，但对于与细胞分裂不严格相关的重要细胞过程也至关重要。本章主要探讨 DNA 损伤反应过程中 CDK/细胞周期蛋白复合物功能的未充分研究的主题。我们详细介绍了 CDK/细胞周期蛋白复合物如何作为 DNA 损伤检查点信号传导的目标以及 DNA 修复的效应物发挥双重作用。此外，我们讨论细胞周期蛋白在这些过程中的潜在 CDK 独立作用以及这些作用在人类疾病（如癌症）中的影响。我们的目标是将焦点放在细胞周期蛋白作为独立实体或 CDK/细胞周期蛋白复合物中的这些重要功能上，这些功能过去很少受到关注。我们认为这对于更全面地了解细胞周期蛋白在 DNA 损伤反应中的复杂功能非常重要。