What is mitochondrial fragmentation?

Mitochondria are dynamic organelles capable of changing their organization and shape based on intracellular and extracellular signals. By balancing cycles of fusion and fission, mitochondria can regulate their morphology.

Mitochondrial fragmentation is the result of decreased fusion and increased fission in mitochondria. It is characterized by a large number of smaller mitochondria—as opposed to a network of highly interconnected and elongated mitochondria, which is the product of increased fusion.

Mitochondrial fragmentation is necessary for mitophagy, since smaller mitochondria are more easily engulfed by autophagosomes than larger ones and require less energy to be autophagocytosed. The fragmented state predominates during periods of high stress as well as before and after the release of apoptogenic factors, which signal for cell death.