A cytochrome c-GFP fusion is not released from mitochondria into the cytoplasm upon expression of Bax in yeast cells

FEBS Lett. 2000 Apr 14;471(2-3):235-9. doi: 10.1016/s0014-5793(00)01404-6.

Abstract

To study Bax-induced release of cytochrome c in vivo, we have expressed a cytochrome c-GFP (green fluorescent protein) fusion in Saccharomyces cerevisiae cells null for the expression of the endogenous cytochrome. We show here that cytochrome c-GFP is efficiently localised to mitochondria and able to function as an electron carrier between complexes III and IV of the respiratory chain. Strikingly, while natural cytochrome c is released into the cytoplasm upon expression of Bax, the cytochrome c-GFP fusion is not. Nevertheless, cells co-expressing Bax and the cytochrome c-GFP fusion die, indicating that mitochondrial release of cytochrome c is not essential for cell death to occur in yeast. The failure to release cytochrome c-GFP is presumed to arise from increased bulk due to the GFP moiety. We propose that in intact yeast cells, Bax-induced release of cytochrome c into the cytoplasm occurs through a selective pore and not as a consequence of the non-specific breakage of the mitochondrial outer membrane.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Biological Transport / drug effects
  • Blotting, Western
  • Cytochrome c Group / chemistry
  • Cytochrome c Group / genetics
  • Cytochrome c Group / metabolism*
  • Cytochromes c*
  • Cytoplasm / drug effects
  • Cytoplasm / enzymology
  • Cytoplasm / metabolism*
  • Doxycycline / pharmacology
  • Electron Transport
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Gene Deletion
  • Gene Expression / drug effects
  • Green Fluorescent Proteins
  • Intracellular Membranes / chemistry
  • Intracellular Membranes / drug effects
  • Intracellular Membranes / metabolism
  • Lasers
  • Luminescent Proteins / chemistry
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Microscopy, Confocal
  • Mitochondria / chemistry
  • Mitochondria / drug effects
  • Mitochondria / enzymology
  • Mitochondria / metabolism*
  • Molecular Weight
  • Nystatin / pharmacology
  • Permeability / drug effects
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-bcl-2*
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / cytology*
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins*
  • Spheroplasts / cytology
  • Spheroplasts / drug effects
  • Spheroplasts / genetics
  • Spheroplasts / metabolism
  • Time Factors
  • bcl-2-Associated X Protein

Substances

  • CYC1 protein, S cerevisiae
  • Cytochrome c Group
  • Fungal Proteins
  • Luminescent Proteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • bcl-2-Associated X Protein
  • Nystatin
  • Green Fluorescent Proteins
  • Cytochromes c
  • Doxycycline