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Archives of Industrial Biotechnology | Volume 2
May 14-15, 2018 | Montreal, Canada
World Yeast Congress
The mitochondrion is an organelle of which the most
important function is to provide energy to the cell
generated by oxidative phosphorylation catalyzed by
the respiratory enzymes. In humans, deregulation of
mitochondrial functions, particularly with regard to the
respiratory chain, is associated with several pathologies. The
activity of the respiratory enzymes may be modulated in
response to metabolic demand and various types of stress.
Several levels of regulation may be conceived, including
post-translational modifications such as phosphorylation.
The steadily increasing number of identified mitochondrial
phosphoproteins suggests that reversible protein
phosphorylation could be an important level of regulation
in mitochondria. However, this hypothesis cannot be tested
without quantitative data on variations in the abundance of
mitochondrial proteins and their level of phosphorylation
under different growth conditions. The yeast Saccharomyces
cerevisiae is a powerful tool for studying various energetic
and physiological states. We realized for the first time
a quantitative study of both protein abundance and
phosphorylation levels in yeast mitochondria under
respiratory (lactate) and fermentative (glucose or galactose)
conditions. Protein abundances were quantified using a
label-free method. The phosphoproteome was analyzed
quantitatively using the multiplex stable isotope dimethyl
labeling procedure. Label free quantitative analysis of
protein accumulation revealed significant variation of
176 mitochondrial proteins. We highlighted significant
differences of the proteome between the two fermentative
substrates.This study enlarges significantly the map of yeast
mitochondrial phosphosites as 670 phosphorylation sites
were identified, of which 214 were new and quantified.
Above all, we showed that 90 phosphosites displayed a
significant variation according to themedium. This proteomic
and phosphoproteomic study is the first extensive study
providing confident quantitative data on mitochondrial
phosphosites responses to different carbon substrates
in the yeast S. cerevisiae mitochondria. The significant
changes observed in the level of phosphorylation according
to the carbon substrate open the way to the study of the
regulation of mitochondrial proteins by phosphorylation
in fermentative and respiratory media. In addition, the
identification of a large number of new phosphorylation sites
show that the characterization of the yeast mitochondrial
phosphoproteome is not yet completed.
Speaker Biography
Lemaire Claire is expert in the biochemistry of membrane proteins. Her scientific
interests have always been focused on energy-transducing systems and in particular
those evolved in organelles. She began her career in the photosynthesis field on the
assembly and regulation of photosynthetic complexes (Institute of Physico-Chemical
Biology, Paris). She then joined the C.N.R.S. (French National Center for Scientific
Research) where she has acquired an excellent appreciation of the mitochondrial
system through the study of the biogenesis of respiratory complexes in yeast and
human using various biochemical and genetic approaches. These last years, she has
developed a new research project with her group focusing on the regulation of the
mitochondrial functions by post-translational modifications.
e:
Regulation of the mitochondrial functions by phosphorylation in the yeast Saccharomyces cerevisiae
Lemaire Claire
Paris-Saclay University, France