Signal transduction pathways involved in the cell response to cytotoxic saponins. Besides the known signaling pathways common to animal and plant cells, additional routes which still need to be verified are shown. CAT, catalase; MT s, metallothioneins; NFκB, nuclear transcription factorκB; NO, nitric oxide; PI3K, phosphatidylinositol-3-kinase; PRX, peroxiredoxin; ROS, Reactive Oxygen Species.