Credit: Wanli Liu A vital intermediate in normal cell metabolism is also, in the right context, a trigger for cell death, according to a new study from Wanli Liu and Yonghui Zhang of Tsinghua University, and Yong Zhang of Peking University in Beijing, publishing 26th April 2021 in the open access journal PLOS biology. The discovery may contribute to a better understanding of the damage caused by stroke, and may offer a new drug target to reduce that damage. Farnesyl pyrophosphate (FPP) is an intermediate in the mevalonate pathway, a series of biochemical reactions in every cell that contributes to protein synthesis, energy production, and construction of cell membranes. During a search for regulators of immune cell function, the authors unexpectedly discovered that FPP, when present at high concentrations outside of cells, caused rapid and extensive death of cells. FPP carries both a highly charged phosphate head and a long hydrophobic hydrocarbon tail, and by altering each in turn, the researchers showed that both were necessary for the effect, suggesting that FPP might interact specifically with some complementary receptors.