Pro-apoptotic effect of maize lipid transfer protein on mammalian mitochondria

To assess the effect of lipids and lipid exchange in the pro-apoptotic release of cytochrome c, we investigated the ability of a plant lipid transfer protein (LTP) to initiate the apoptotic cascade at the mitochondrial level. The results show that maize LTP is able to induce cytochrome c release from the intermembrane space of mouse liver mitochondria without significant mitochondrial swelling, similarly to mouse full-length Bid. This effect is influenced by the presence of specific lipids, since addition of lysolipids like lysophosphatidylcholine strongly stimulates the LTP-induced release of cytochrome c while it is inhibited by removal of endogenous free lipids with a complete suppression of the LTP-induced release of cytochrome c. The results are discussed in light of the possible role of lipid exchange in apoptosis.