Cyclin-dependent kinases (CDKs) are a family of enzymes that play a crucial role in regulating the cell cycle. They are activated by binding to specific proteins called cyclins, which help control the progression of cells through different phases, such as mitosis and interphase. Once activated, CDKs phosphorylate target proteins, leading to various cellular processes, including DNA replication and cell division. The activity of CDKs is tightly regulated to ensure proper cell cycle progression and prevent uncontrolled cell growth, which can lead to conditions like cancer.