Phalloidin is a bicyclic heptapeptide toxin that binds to F-actin, a filamentous protein that is a crucial component of the cell's cytoskeleton. Its binding stabilizes the actin filaments, preventing their depolymerization. This action disrupts normal cellular function, leading to cell death, which is why phalloidin is highly toxic. While phalloidin itself is not absorbed from the gastrointestinal tract, it is often used as a tool in cell biology research to stain and visualize actin filaments.
