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A cytochrome c –GFP fusion is not released from mitochondria into the cytoplasm upon expression of Bax in yeast cells
Author(s) -
Roucou Xavier,
Prescott Mark,
Devenish Rodney J,
Nagley Phillip
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01404-6
Subject(s) - cytochrome c , green fluorescent protein , cytoplasm , mitochondrion , cytochrome , cytochrome c1 , biology , microbiology and biotechnology , cytochrome b , yeast , saccharomyces cerevisiae , mitochondrial apoptosis induced channel , coenzyme q – cytochrome c reductase , biochemistry , chemistry , mitochondrial dna , gene , enzyme
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.