PLK (Polo-like kinase) family includes several members, from PLK1 to PLK5, each with a kinase activity domain. These proteins are mainly localized in the cytoplasm and nucleus, regulating mitosis and DNA damage response. PLKs activate cell cycle progression, promote chromosome segregation, and organelle positioning, participating in crucial signaling pathways. Expression of PLK is higher in rapidly dividing cells, and mutations in these genes can lead to cell cycle dysregulation, associated with diseases like cancer.