Uncoupled mitochondria quickly shorten along their long axis to form indented spheroids, instead of rings, in a fission-independent manner

Sci Rep. 2018 Jan 10;8(1):350. doi: 10.1038/s41598-017-18582-6.


Loss of mitochondrial membrane potential (ΔΨm) triggers dramatic structural changes in mitochondria from a tubular to globular shape, referred to as mitochondrial fragmentation; the resulting globular mitochondria are called swelled or ring/doughnut mitochondria. We evaluated the early period of structural changes during the ΔΨm loss-induced transformation after carbonyl cyanide m-chlorophenyl hydrazine (CCCP) administration using a newly developed correlative microscopic method combined with fluorescence microscopic live imaging and volume electron microscopy. We found that most mitochondria changed from a tubular shape to a globular shape without fusion or fission and typically showed ring shapes within 10 min after CCCP exposure. In contrast, most ring mitochondria did not have a true through hole; rather, they had various indents, and 47% showed stomatocyte shapes with vase-shaped cavities, which is the most stable physical structure without any structural support if the long tubular shape shortens into a sphere. Our results suggested that loss of ΔΨm triggered collapse of mitochondrial structural support mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Fibroblasts
  • HeLa Cells
  • Humans
  • Membrane Potential, Mitochondrial
  • Mice
  • Mitochondria / metabolism*
  • Mitochondria / ultrastructure*
  • Mitochondrial Dynamics*
  • Models, Biological
  • Reactive Oxygen Species / metabolism
  • Time-Lapse Imaging


  • Reactive Oxygen Species