Proteolytic cleavage of Opa1 stimulates mitochondrial inner membrane fusion and couples fusion to oxidative phosphorylation Academic Article uri icon


MeSH Major

  • GTP Phosphohydrolases
  • Membrane Fusion
  • Mitochondrial Membranes
  • Oxidative Phosphorylation
  • Proteolysis


  • Mitochondrial fusion is essential for maintenance of mitochondrial function. The mitofusin GTPases control mitochondrial outer membrane fusion, whereas the dynamin-related GTPase Opa1 mediates inner membrane fusion. We show that mitochondrial inner membrane fusion is tuned by the level of oxidative phosphorylation (OXPHOS), whereas outer membrane fusion is insensitive. Consequently, cells from patients with pathogenic mtDNA mutations show a selective defect in mitochondrial inner membrane fusion. In elucidating the molecular mechanism of OXPHOS-stimulated fusion, we uncover that real-time proteolytic processing of Opa1 stimulates mitochondrial inner membrane fusion. OXPHOS-stimulated mitochondrial fusion operates through Yme1L, which cleaves Opa1 more efficiently under high OXPHOS conditions. Engineered cleavage of Opa1 is sufficient to mediate inner membrane fusion, regardless of respiratory state. Proteolytic cleavage therefore stimulates the membrane fusion activity of Opa1, and this feature is exploited to dynamically couple mitochondrial fusion to cellular metabolism.

publication date

  • April 2014



  • Academic Article



  • eng

PubMed Central ID

  • PMC4018240

Digital Object Identifier (DOI)

  • 10.1016/j.cmet.2014.03.011

PubMed ID

  • 24703695

Additional Document Info

start page

  • 630

end page

  • 41


  • 19


  • 4