Growth yield homeostasis in respiring yeast is due to a strict mitochondrial content adjustment.
In living cells, growth is the result of coupling between substrate catabolism and multiple metabolic processes taking place during net biomass formation and cell property maintenance. A crucial parameter for growth description is its yield, i.e. the efficiency of the transformation from substrate consumption to biomass formation. Using numerous yeast strains growing on different respiratory media, we have shown that the growth yield is identical regardless of the strain, growth phase, and respiratory substrate used. This homeostasis is the consequence of a strict linear relationship between growth and respiratory rates. Moreover, in all conditions tested, the oxygen consumption rate was strictly controlled by the cellular content of respiratory chain compounds in such a way that, in vivo, the steady state of oxidative phosphorylation was kept constant. Thus, the growth yield homeostasis depends on the tight adjustment of the cellular content of respiratory chain compounds to the growth rate. Any process leading to a defect in this adjustment allows an energy waste and consequently an energy yield decrease.
Devin
Anne
A
Institute of Biochemistry and Genetics of the Cell, CNRS Unité Mixte de Recherche 5095-Université Bordeaux 2, 1 Rue Camille Saint Saëns, 33077 Bordeaux Cedex, France.
Dejean
Laurent
L
Beauvoit
Bertrand
B
Chevtzoff
Cyrille
C
Avéret
Nicole
N
Bunoust
Odile
O
Rigoulet
Michel
M
D000255:Adenosine Triphosphate / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism; D006706:Homeostasis; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013816:Thermodynamics
D003580:Cytochromes; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D010100:Oxygen