Crucial mitochondrial impairment upon CDC48 mutation in apoptotic yeast.
Mutation in CDC48 (cdc48(S565G)), a gene essential in the endo-plasmic reticulum (ER)-associated protein degradation (ERAD) pathway, led to the discovery of apoptosis as a mechanism of cell death in the unicellular organism Saccharomyces cerevisiae. Elucidating Cdc48p-mediated apoptosis in yeast is of particular interest, because Cdc48p is the highly conserved yeast orthologue of human valosin-containing protein (VCP), a pathological effector for polyglutamine disorders and myopathies. Here we show distinct proteomic alterations in mitochondria in the cdc48(S565G) yeast strain. These observed molecular alterations can be related to functional impairment of these organelles as suggested by respiratory deficiency of cdc48(S565G) cells. Mitochondrial dysfunction in the cdc48(S565G) strain is accompanied by structural damage of mitochondria indicated by the accumulation of cytochrome c in the cytosol and mitochondrial enlargement. We demonstrate accumulation of reactive oxygen species produced predominantly by the cytochrome bc1 complex of the mitochondrial respiratory chain as suggested by the use of inhibitors of this complex. Concomitantly, emergence of caspase-like enzymatic activity occurs suggesting a role for caspases in the cell death process. These data strongly point for the first time to a mitochondrial involvement in Cdc48p/VCP-dependent apoptosis.
Braun
Ralf J
RJ
GSF-National Research Center for Environment and Health, Institute of Human Genetics, Ingolstaedter Landstrasse 1, Munich-Neuherberg D-85764, Germany.
Zischka
Hans
H
Madeo
Frank
F
Eisenberg
Tobias
T
Wissing
Silke
S
Büttner
Sabrina
S
Engelhardt
Silvia M
SM
Büringer
Dietmute
D
Ueffing
Marius
M
D000251:Adenosine Triphosphatases; D017209:Apoptosis; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D051336:Mitochondrial Membranes / Q000737:chemistry; D017382:Reactive Oxygen Species; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013347:Subcellular Fractions; D000074405:Valosin Containing Protein
D018797:Cell Cycle Proteins; D017382:Reactive Oxygen Species; D029701:Saccharomyces cerevisiae Proteins; D045304:Cytochromes c; D000251:Adenosine Triphosphatases; C000614177:CDC48 protein, S cerevisiae; C000614178:VCP protein, human; D000074405:Valosin Containing Protein