Sterol regulatory element-binding proteins (SREBPs) play a crucial role in lipid biosynthesis. In a recent study, researchers identified a novel cleavage enzyme of SREBP-1c, a key player in fatty acid biosynthesis. Moreover, the team unveiled, for the first time, that the biosynthesis process of fatty acid in the liver is activated by saturated fatty acids and inhibited by polyunsaturated fatty acids, providing new insights into the intricate workings of this cleavage system.