Mitochondrial kiss-and-run: Interplay between mitochondrial motility and fusion-fission dynamics

Xingguo Liu, David Weaver, Orian Shirihai, György Hajnóczky

Research output: Contribution to journalArticlepeer-review

266 Scopus citations


Visualizing mitochondrial fusion in real time, we identified two classes of fusion events in mammalian cells. In addition to complete fusion, we observed transient fusion events, wherein two mitochondria came into close apposition, exchanged soluble inter-membrane space and matrix proteins, and re-separated, preserving the original morphology. Transient fusion exhibited rapid kinetics of the sequential and separable mergers of the outer and inner membranes, but allowed only partial exchange of integral membrane proteins. When the inner membrane fusion protein Opa1 level was lowered or was greatly elevated, transient fusions could occur, whereas complete fusions disappeared. Furthermore, transient fusions began from oblique or lateral interactions of mitochondria associated with separate microtubules, whereas complete fusions resulted from longitudinal merging of organelles travelling along a single microtubule. In contrast to complete fusion, transient fusions both required and promoted mitochondrial motility. Transient fusions were also necessary and sufficient to support mitochondrial metabolism. Thus, Opa1 expression and cytoskeletal anchorage govern a novel form of fusion that has a distinct function in mitochondrial maintenance.

Original languageEnglish
Pages (from-to)3074-3089
Number of pages16
JournalEMBO Journal
Issue number20
StatePublished - 1 Oct 2009
Externally publishedYes


  • Calcium
  • Cytoskeleton
  • Fusion
  • Mitochondria
  • Motility

ASJC Scopus subject areas

  • General Neuroscience
  • Molecular Biology
  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology


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