Brefeldin A (BFA) is a lactone antibiotic and a specific inhibitor of protein trafficking. Brefeldin A blocks the transport of secreted and membrane proteins from endoplasmic reticulum to Golgi apparatus^[1][2]. Brefeldin A is also an autophagy and mitophagy inhibitor^[3]. Brefeldin A is a CRISPR/Cas9 activator^[5]. Brefeldin A inhibits HSV-1 and has anti-cancer activity^[5]. IC50 & Target: Autophagy^[3], CRISPR/Cas9^[5] In Vitro: Brefeldin A (BFA) treatment for 15 h or 40 h, causes dramatic swelling of the Endoplasmic Reticulum (ER) and shifts its localization to the periphery of normal rat kidney (NRK) cells. Prolonged Brefeldin A treatment results in marked disruption of the MT and actin cytoskeleton^[1]. ADP-ribosylation of BARS is mediated by formation of a conjugate between Brefeldin A and ADPR. BARS shows BAC binding when incubated with the medium from the BFA-treated CD38⁺ HeLa cells^[3]. Brefeldin A induces anchorage-independent cell death in MDA-MB-231 breast cancer cells, inhibits the formation of MDA-MB-231 colonies in 3D and 2D cultures and inhibits the migration and MMP 9 (Matrix Metallopeptidase 9) activity of MDA-MB-231^[2].