Introduction

Cell death pathways use genetically encoded and derived components to transduce specific death-inducing signals into a common phenotype associated with death. These signals often include steps that impinge on mitochondria as a means of initiating or amplifying the process. Because mitochondria are organelles that contain unshared lipid and protein components, this makes them ideal targets for specific integration into cell death pathways at defined steps because of the actions of proteins present in the cytosol that target and respond to these unique components. Mitochondria are the site of the cell's major energy-generating system that produces adenosine triphosphate (ATP), used to maintain vital cellular functions. By being involved in these two conflicting processes, a cell ensures that mitochondrial energy generation and cell death are generally exclusive events. This is compatible with cellular fate ensuring shut-down of anabolic processes and favoring dismantling of cellular architecture and function, thus making death proceed in a swift manner. Here we discuss the function of mitochondria in apoptosis and necrosis and how these roles affect other aspects of mitochondrial biology.