In a paper in Nature Communications, a team from Sun Yat-sen University and other centers in China and Australia uncover an inhibitor for a poisonous compound found in the Amanita phalloides death cap mushroom. The investigators identified a compound called indocyanine green (ICG) — a fluorescent iodide dye that has been used diagnostically for decades — that inhibits the STT3B catalytic enzyme behind alpha-amanitin toxicity with a CRISPR screen, drug screening experiments using thousands of compounds, and follow-up functional validation experiments in cell lines, organoids, and mouse models. "Together, by combining a genome-wide CRISPR screen for alpha-amanitin toxicity with an in silico drug screen and functional validation in vivo, our study highlights ICG as a STT3B inhibitor against the mushroom toxin," they report.