Spatio-temporal organization of the mitochondrial phase of apoptosis

Signaling cascades often utilize highly ordered interactions between intracellular organelles to propagate a particular signal throughout the cell. In many apoptotic paradigms, the stress signal is delivered to the mitochondria, and mitochondria release to the cytosol several apoptotic factors, which in turn, trigger execution of the program of cell suicide. Although intermitochondrial communication has been shown to give rise to regenerative phenomena such as Ca2+ release waves and depolarization waves, it has not been elucidated whether mitochondria interact with each other during apoptosis and whether the postmitochondrial phase of apoptosis displays a coordinated response throughout the cell. The objective of this review is to draw attention to recent observations that shed some light onto the subcellular spatio-temporal organization of the apoptotic machinery.