The BUB (Budding Uninhibited by Benzimidazoles) family consists of cell division checkpoint proteins, primarily including BUB1 and BUB3. These proteins are predominantly located at the spindle checkpoint in cells, ensuring correct chromosome segregation. BUB proteins participate in controlling the cell cycle process by activating signaling pathways, playing a crucial role particularly in mitosis. Expression of BUB genes is typically upregulated during active mitosis. Specific mutations or dysregulation of expression can lead to abnormal cell division, closely associated with the development of various cancers.