Dying a thousand deaths: redundant pathways from different organelles to apoptosis and necrosis.

Cell death is an essential event in normal life and development, as well as in the pathophysiological processes that lead to disease. Although the literature on cell death has grown enormously in size and complexity, a pattern has emerged that each of several distinct organelles (plasma membrane, mitochondrion, nucleus, endoplasmic reticulum, lysosome) gives rise to signals that induce cell death. Most often these signals converge on mitochondria to initiate a common pathway to either caspase-dependent apoptosis or ATP depletion-dependent necrosis. This brief overview emphasizes the multiple and often redundant pathways between different organelles that lead ultimately to a cell's demise.