Mitoptosis: different pathways for mitochondrial execution.

Mitoptosis was described as a sort of mitochondrial death program. It could be associated with both necrosis and apoptosis, although degenerating mitochondria are also found in autophagic vacuoles. It was demonstrated that several molecules might contribute to the remodeling and rearrangement of mitochondrial membranes, leading to mitochondria rupture and disruption. Here, we hypothesize that, at least in T cells, two main pathways of mitoptosis can occur: an inner membrane mitoptosis (IMM), in which only the internal matrix and cristae are lost while the external mitochondrial envelope remains unaltered, and an outer membrane mitoptosis (OMM) where only swollen internal cristae are detected as remnants. We suggest that the study of these processes could provide useful insights not only to the field of cell death but also to the study of the pathogenic mechanisms of mitochondria-associated human diseases.