Brefeldin A is widely used in biological research to study protein transport and secretion within cells. It inhibits protein secretion by disrupting the Golgi apparatus, making it a valuable tool for understanding intracellular trafficking pathways. Researchers use it to investigate the mechanisms of vesicle formation, endoplasmic reticulum (ER) to Golgi transport, and the role of specific proteins in these processes. Additionally, it is employed in cancer research to study apoptosis and cell cycle regulation, as it can induce cell death in certain cancer cell lines. Its ability to interfere with cellular processes also makes it useful in virology for examining viral replication and assembly.