The myxoma poxvirus protein, M11L, prevents apoptosis by direct interaction with the mitochondrial permeability transition pore

Helen Everett, Michele Barry, Xuejun Sun, Siow Fong Lee, Christine Frantz, Luc G. Berthiaume, Grant McFadden, R. Chris Bleackley

Research output: Contribution to journalArticle

87 Scopus citations


M11L, an antiapoptotic protein essential for the virulence of the myxoma poxvirus, is targeted to mitochondria and prevents the loss of mitochondrial membrane potential that accompanies cell death. In this study we show, using a cross-linking approach, that M11L physically associates with the mitochondrial peripheral benzodiazepine receptor (PBR) component of the permeability transition (PT) pore. Close association of M11L and the PBR is also indicated by fluorescence resonance energy transfer (FRET) analysis. Stable expression of M11L prevents the release of mitochondrial cytochrome c induced by staurosporine or protoporphyrin IX (PPIX), a ligand of the PBR. Transiently expressed M11L also prevents mitochondrial membrane potential loss induced by PPIX, or induced by staurosporine in combination with PK11195, another ligand of the PBR. Myxoma virus infection and the associated expression of early proteins, including M11L, protects cells from staurosporine- and Fas-mediated mitochondrial membrane potential loss and this effect is augmented by the presence of PBR. We conclude that M11L regulates the mitochondrial permeability transition pore complex, most likely by direct modulation of the PBR.

Original languageEnglish (US)
Pages (from-to)1127-1139
Number of pages13
JournalJournal of Experimental Medicine
Issue number9
StatePublished - Nov 4 2002
Externally publishedYes



  • Apoptosis
  • Mitochondria
  • PK11195
  • Poxviridae
  • Protoporphyrin IX

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Cite this