Open AccessInvestigation of bax‐induced release of cytochrome c from yeast mitochondria
Author(s) -
Priault Muriel,
Chaudhuri Bhabatosh,
Clow Angela,
Camougrand Nadine,
Ma Stéphen
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00198.x
Subject(s) - voltage dependent anion channel , cytochrome c , mitochondrion , mitochondrial apoptosis induced channel , inner membrane , bacterial outer membrane , apoptosome , microbiology and biotechnology , intermembrane space , translocase of the inner membrane , mitochondrial permeability transition pore , mitochondrial intermembrane space , biology , cytosol , inner mitochondrial membrane , cytochrome , mitochondrial membrane transport protein , biochemistry , saccharomyces cerevisiae , mitochondrial carrier , yeast , apoptosis , programmed cell death , enzyme , caspase , escherichia coli , gene
Recent studies that attempt to explore the action of pro‐ and anti‐apoptotic proteins of the bcl2 family demonstrate the crucial role of relocalization of cytochrome c from the mitochondrial intermembrane space to the cytosol. This early event of apoptosis can be mimicked in the yeast Saccharomyces cerevisiae following expression of bax. In mammalian mitochondria, the mechanism of relocalization is thought to involve the opening of the so‐called permeability transition pore. We show in this paper: (a) that bax‐induced release of cytochrome c in yeast does not involve any permeability transition of the inner mitochondrial membrane but involves a general alteration of the permeability of the outer mitochondrial membrane to macromolecules. This suggests that a permeability transition of the inner mitochondrial membrane is not an event required for the relocalization of cytochrome c in yeast. (b) The outer‐membrane voltage‐dependent anion channel (VDAC), a putative component of the permeability transition pore, is not involved in bax‐induced release of cytochrome c or in the prevention of this release by bcl‐x L . (c) Bax devoid of its C‐terminal putative hydrophobic α‐helix is as efficient as full‐length bax to allow the relocalization of cytochrome c , demonstrating this segment of the protein is not required for membrane‐targeting. (d) We finally observe that the action of bax on the outer mitochondrial membrane requires the presence of ATP both in vitro and in vivo , and it is shown that ATP directly increases the amount of bax inserted to mitochondria.